Final Report Summary - INTELLI-FLUE (Intelligent combustion management of flue gases for solid fuel domestic heating systems)
Executive Summary:
Having commenced in February 2011, the Intelli-Flue project set about the development of a novel energy recovery system, combined with a state of the art protective flue liner. The project lasted for a duration of 2 years.
The vast majority of European homeowners live in a property that has an operational chimney. A large number of consumers assume that a functional chimney, used regularly over a number of years, will represent little or no threat to their safety. The unfortunate reality is that poor chimney maintenance can be the cause of significant injury or even death, due to the threat of chimney fires. There is currently a noticeable lack of awareness amongst consumers, and as a result, chimney integrity is not questioned until after a fire.
Processed and poor quality solid fuels produce highly corrosive flue gases that significantly reduce the lifetime of flue liners. Such fuels are often marketed as being highly reliable, more efficient and cheaper than seasoned alternatives. Additional risk is posed by increased flue gas temperatures from high efficient solid fuel stoves, flue liners are failing to reduce serious chimney fires.
The Intelli-Flue project has been conducted by a highly committed consortium consisting of 6 Small to Medium Sized Enterprises (SMEs), supported by 3 European research institutes. Each member has contributed whole heartedly towards the development of the Intelli-Flue solution. When combined, the expertise within the consortium has aided the project to move towards a commercially viable solution, overcoming a variety of technical challenges within the lifetime of the project.
The Intelli-Flue solution provides a solution to address the issue of highly corrosive flue gases and elevated flue gas temperatures by developing a protective ceramic liner, with increased durability performance, alongside a novel heat recovery system. This will enable domestic stoves, old and new, to burn efficiently, harnessing any waste heat for use as a source of domestic heat. Additional benefits include limitation of flue gas temperatures, and thus the risk of chimney fires. The combination will enable homeowners to continue to use solid safely without risking the building and its occupants.
The Intelli-Flue products can save money. It is not a luxury item. The Heat Exchanger saves the end user money on the most expensive part of any household expenditure, heating. The Intelli-Flue liner has the potential to save our customers money on their home insurance policies. Maintenance costs could be reduced, and lifespan of the product substantially increased. Intelli-Flue promotes solid fuels as alternatives to oil and gas for the purposes domestic heating. With concerns over energy supply set to continue, Intelli-Flue will help Europe to better utilise solid fuel resources and diversify our energy mix, assisting the European Community to meet EU energy targets.
Project Context and Objectives:
The Intelli-Flue project consortium was successful in obtaining funding support from the European Commission, within the funding programme Research for the Benefit of SMEs, to support our ambitious, yet highly innovative development project. The project commenced during January 2011, and lasted for a period of 2 years. During this time, we have set out to investigate the proposed objectives, through a combined effort of our consortium members. The Intelli-Flue consortium consists of 6 SMEs, representing 5 EU member states. This transnational approach has been of significant value to the consortium, with regular interaction taking place between all parties, a number of business opportunities, external to the project have already been explored. The consortium has employed the services of 3 research performers, UK Materials Research Institute, Ikerlan and Aachen University. Throughout the project, the technical contribution made by our researchers has enabled the SME supply chain to focus heavily upon the commercial elements of the project, detailing production plans and exploitation strategies that will see the Intell-Flue product taken to market following a successful delivery of the initial research project. The consortium is buoyed by the results provided within the first stage, and has consequently submitted an application for a follow-on project, which would address the demonstration and fine tuning of the Intelli-Flue product. If successfully granted, this project would be financed under the European Commission’s ‘Demonstration Activity’ funding.
The history behind the development of the Intelli-Flue concept is the result of a wide variety of contributions from industry leaders within the field of chimney maintenance, insurance and building services.
With concerns over energy supply set to continue, consumers are looking for sustainable, price resilient alternatives to oil and gas. At present, the most likely candidates to provide an alternative are solid fuels such as biomass (wood). It is possible that even coal can be considered following the latest new findings within the UK and across Europe. European countries are promoting the better utilisation of solid fuel resources in an attempt to diversify our energy mix to meet pre-set EU energy targets. Solid fuel stove burners have potential to achieve 75-80% combustion efficiency enabling solid fuels such as wood, energy crop and coal to be viable domestic heating alternatives to oil and gas. As a consequence, solid fuel stoves’ sales are on the increase; however, with increased domestic solid fuel use there has been an increase in stove/chimney related serious house fires. It should be considered, however, that the efficiency of the vast majority of stoves on the market today is heavily limited. This could be due to poor installation, unfavourable fuel selection and less than optimal operating conditions. Market knowledge within the consortium suggests that the level of efficiency provided by most stoves is closer to 35/50%.
The quality of the fuel being combusted is a major contributory factor to chimney related fires. At Thatched Owners Group Ltd (TOG) we are seeing unseasoned/poor quality fuels and in particular, processed solid fuels producing highly corrosive flue gases that are significantly reducing the lifetime of flue liners (sulphur and chlorine mixtures from condensates reacting with moisture to produce acidic complexes). In some instances corrosion has resulted in rapid failure within 5 years or less, despite manufacturers claims of a life of 25 years. As steel has a high thermal conductivity, it is subject to rapid cooling when the fire in the stove is dying out, promoting condensates to form which lead to corrosion attack on the metal.
The proposed concept will not only enable the consumer to increase the level of safety, and efficiency within their home but also contribute towards the following EU policies:
European Energy Consumers Charter
Energy Performance of Buildings
EU Biomass Action Plan
Kyoto-Target CO2 Plan
Chimney safety is currently a well debated topic at pan European level, with legislation under review across the majority of the EU27. Intelli-Flue can contribute towards improved safety measures, and represents a cost effective solution for a real life problem. To compound the problem, high-efficiency solid fuel burners (secondary/tertiary burn) coupled with consumers purchasing stoves based on grandeur and size means today’s installed stoves are over-specified. Increased flue gas temperatures lead to the potential for heat transmission through the chimney to the building and any combustible materials used in the building construction (e.g. wood timbers and/or thatch).
Intelli-Flue originally set out to develop a solution for a flexible ceramic flue liner that enables easy installation at an acceptable cost for the end-user. This would prevent the corrosion problems presented towards metal flue liners when poor quality, corrosive solid fuel is used for domestic heating. A solution that aims to reduce fire risk to a building and its occupants will also address higher flue gas temperatures from today’s highly efficient stoves. Following initial stages of research and development, the consortium discovered that the development of a pre-impregnated liner, comprising of a flexible ceramic liner, would not prove to be a commercially viable option. This idea was hampered significantly by the mid/long term storage process of the liner, the transportation methods available and the curing process required following installation into the chimney. The project therefore made a deviation, still maintaining the original objective to create a refractory ceramic formulation with much improved properties compared to those available on the market today. This would then be applied in situ.
The second component of the Intelli-Flue product is a state of the art energy recovery system. It is suggested that up to 75% of the heat energy produced within a stove is lost to the flue. This energy represents lost potential which is deemed useless. Our heat recovery system will provide the opportunity to recirculate this energy within the home’s domestic heating system. The Intelli-Flue project will deliver improvements in both thermal efficiency to be achieved by the stove as well as user comfort and assurance. Current solutions are haunted by the fact that they are either not aesthetically pleasing, or they require constant operator attendance. In today’s modern era, this is not acceptable, nor commercially viable. Substantial efforts have also been made in order to ensure maximum safety performance within the system, providing reassurance to the end user that the risk of overheating is minimised. This is aided by the development of a comprehensive combustion control system within the project. Combined, the project was setting out to achieve actual thermal efficiency for the stove of up to 90%.
The integration of the Intelli-Flue heat exchanger module will also assist in limiting the temperatures of which the flue liner shall be exposed. This will be possible due to the fact that energy is transferred to alternative uses such as heating rather than direct exhaust through the chimney.
In summary, the Intelli-Flue technology is made up of 3 core developments (areas of research focus), each presenting their own objectives that needed to be achieved within the lifetime of the project. A summary of these and their associated objectives can be found below:
Heat Recovery System
Develop fumes/water heat exchanger designed to limit flue gas temperatures to a max. 750°C.
Develop an air damper to modify and establish the potential for adaptive combustion control.
Establish waste heat recovery performance characteristics.
Integrate a waste heat recovery system and liner to evaluate energy recovery performance. Deliver 70% heat exchanger efficiency.
Textile Flue Liner
Define liner construction to limit heat transfer from the flue gases to brickwork/surrounding structures to a maximum of 175°C.
Develop liner flexibility (bend radii of 60º) to reduce installation time by 50% compared to current ceramic/clay systems.
Deliver 650°C liner operation (operating limit of 750°C) for 4 hours. Contain a flue fire 1100°C for a minimum of 30 minutes [BS EN 13063 part 1].
Ceramic Cement Formulation
Develop ceramic-cement formulation to deliver corrosion performance for acidic (pH2.5) flue environments.
Develop ceramic-cement formulation to cope with temperature cycling (5°C to 750°C) and for impregnation into the inner surface liner.
The Intelli-Flue project has sought to produce a cost effective, responsible solution to meet the challenge of improving the safety and viability of domestic heating via the use of solid fuels. The project has developed a range of novel innovations which represent a valuable commercial opportunity for each of the SME consortium members. These are summarised by the following:
• Textile Liner Design
• Textile Manufacturing Process
• Heat Exchanger Design
• Ceramic Cement Formulation
• Combustion Control System
The use of poor quality fuels on domestic stoves represents an extremely harsh environment for the surrounding features. For example, the temperatures produced within a domestic stove can reach in excess of 600 °C, with acidic gasses reaching extremes of pH2 in some cases. This is caused as a result of the sulphur and chlorine gasses given off by a range of fuels. It is therefore imperative that the Intelli-Flue liner system is capable of operating within these conditions. Such temperatures pose a significant threat to external structures, for example exterior brickwork, wooden beams or straw thatch, which when exposed to such temperatures can have a tendency to catch fire. This poses a significant risk to habitants and surrounding homes. We have therefore ensured that the textile liner incorporated within our system limits the heat transfer from the interior layer to the exterior fabric, with the resulting exterior temperature being less than 175 °C.
The Intelli-Flue liner will deliver the following characteristics:
• Corrosion resistant lining – abrasion resistant surface (for sweeping) that will contain flue gases at elevated temperatures and in a highly corrosive environment.
• Highly insulating liner – minimise heat transfer to the chimney and surrounding structures.
• Flexible circular liner construction – deliver uniform insulation (no seam or ‘weak point’ for heat to be conducted through) and introduce easy installation.
Project Results:
1. DESIGN AND SPECIFICATION
1.1 HEAT RECOVERY SYSTEM
Heat energy provided into the home through combustion of the wood/fuel is generally provided through radiation. Small quantities of heat are also provided by the natural process of convection. Most stoves, when in operation, are able to return a thermal efficiency rate of up to 50%. The Intelli-Flue consortium can therefore conclude that the heat energy lost to the chimney is significant and should not be ignored.
User comfort is also of paramount importance for any such technology entering the domestic heating market. Throughout the project this has been at the forefront of discussion, and where possible acted upon to be incorporated into our final design. Domestic stoves are generally viewed as being simple heating systems, with a manual method of controlling thermal power. This is typically achieved through varying the wood feed rate and/or adjusting the chimney’s draught level. Stoves within the global market today can also be noted as having very little potential for heat recovery. Existing systems require continuous human attendance, which in a modern era is becoming increasingly inconvenient.
Within Deliverable 1.3 (D1.3) the targeted requirements for the heat recovery system were presented. A summary of these identified objectives is provided within Table 1.
Table 1. Heat Recovery System Objectives
Objective Comments
Provide a high level of thermal efficiency.
Increase the level of thermal efficiency above 70%.
To be available at reasonable cost. I.e. provide a payback period of less than 10 years.
Consider production costs/manufacturing methods to ensure a cost viable solution.
To meet the required EN standards for stove operation.
Obtain feedback from expertise within the project consortium.
To maintain an aesthetically pleasing design.
Adhere to pre-set size requirements. Ensure presentation is in parallel with existing stoves on the market today.
A joint collaboration between AIC (SME) and Ikerlan (RTD) has led to the successful development of a Heat Recovery System adhering to the preset project objectives. A core component of this system, which has undergone extensive development work within the project, is the Heat Exchanger system. A key area of novelty that was presented within the initial Intelli-Flue design was the notion that a heat exchanger system could be applied to a domestic stove, utilising the excess heat that would be ordinarily lost to the flue.
The main design specifications for the Intelliflue HE were defined as the following:
• The HE must be cost effective (simple design).
• Maximum allowed dimensions: 400 mm height (max 600 mm, including top and bottom conical sections), 225 mm outside diameter, allowing for a 150 mm flue pipe connection on top and bottom).
• Should not weigh more than 20 kg.
• Minimum heat transfer from the fuel to the water: 2.5 kW, with 60 ºC water inlet temperature.
• No fumes condensation is permitted.
• The system should be aesthetically pleasing, and easy to perform cleaning maintenance.
• System efficiency range between 70% and 80%.
• The level of pressure drop throughout the HE unit should be below 10 Pa, as the minimum allowed draught in the chimney is 13 Pa (at nominal firepower). Moreover, the heat transferred to the water should be significantly higher than 2 kW to make it possible to rise the overall stove’s efficiency from 50% to 70%.
The provision of increased thermal efficiency is reliant upon the control of a range of variable parameters, which were considered in depth throughout the project. These are demonstrated within Table 2. Having successfully identified these, it was then necessary to incorporate their consideration within our future testing and analysis.
Table 2. Variable Parameters for Consideration
Parameter Dependent Factor Action
Level of Fume Flow Stove’s combustible load Define constant loading value
Fuel Description (I.e. seasoned or unseasoned) Select constant fuel
Fuel Shape Define regular branding/source of fuel throughout the project.
Fumes Inlet Temperature Test Stove’s Efficiency Level Use of single stove for testing.
Water Flow Rate Use of pump or natural draught Investigation of most appropriate solution during project.
Water Inlet Temperature Efficiency of the Heat Transfer System within the Home Transfer heat to a standard water tank during testing.
The expected temperature for the heat exchanger’s (HE) water inlet will be highly dependent upon the home’s heat transfer system. As a guide the following temperatures were identified:
- 25-30 ºC, for radiant floor
- 30-35 ºC, for fan-cooling (air) based heating
- 45-50 ºC, for low temperature radiators, and
- 60-65 ºC, for high temperature radiators.
This temperature must be taken in to consideration, due to the fact that the efficiency that can be provided by the HE is directly linked to this information. Should the temperature of the inlet differ significantly, the other factors become unknown. We would therefore be unable to predict the efficiency of the system to an accurate level. This is of even more importance in solid fuel stoves as supposed to alternative domestic heating appliances, for example, boilers or water heating tanks. This is due to the fact that in boilers, the average fume temperature is higher than 1000°C. However, it is thought that in the case of a stove, the expected temperature of the fumes entering the HE will normally remain less than 550°C. As a general rule, within a correctly functioning heat exchanger, the higher the inlet water temperature, the lower the HE efficiency measurement.
Having assessed these requirements, a number of alternative designs were produced for the desired HE. Table 3 presents a summary of 5 designs assessed as part of the development process. Comparisons were made between each individual design, with conclusions drawn based on their theoretical performance. Initial testing was conducted on a software basis (CAD); this was able to assist in identifying which designs should be taken forward to the production phase.
Table 3. Summary of Potential HE Designs
Version 1
Three rows of tubes with 25, 35 and 45 tubes (a total of 105 fumes tubes).
Tube geometry:
Tube length = 120 mm
Central fumes bypass tube.
Results from the CFD analysis:
Heat transferred = 3.27 kW
Pressure drop in fumes = 2.0 Pa
Mean outlet fumes temperature = 100°C.
Conclusion:
The HE is oversized. High risk of condensation
Water side design not analysed
Version 2
One single row of 36 tubes in a single circumference.
Tube geometry:
a=7 mm; b=5 mm; c=34 mm: d=41mm
Tube length = 120 mm
Central fumes bypass tube
Results from the CFD analysis:
Heat transferred = 1.96 kW
Pressure drop in fumes = 8.7 Pa
Mean outlet fumes temperature = 221 ºC
Conclusion:
HE is clearly undersized, and this tube tube’s geometry is not manufactured by AIC
Water side design not analyzed
Version 3
One single row with 23 tubes in a single circumference. Longer and thinner HE.
Tube geometry:
a=7 mm; b=5 mm; c=34 mm: d=41mm
Tube Length = 190 mm (120 mm modelled)
Central fumes bypass tube
Results from the CFD analysis:
Heat transferred = 1.46 kW (2,31kW for a 190mm long tube)
Pressure drop in fumes = 13.5 Pa
Mean outlet fumes temperature = 275 ºC
Conclusion:
Heat transfer nearly sufficient but fumes pressure drop too high.
Version 4
One single row with 32 tubes in a single circumference. Bigger cross-section tubes.
Tube geometry:
a=7 mm; b=5 mm; c=54 mm: d=64mm
Tube Length = 150 mm
No fumes bypass tube (tube blocked)
Results from the CFD analysis:
Heat transferred = 2.21 kW
Pressure drop in fumes = 1.8 Pa
Mean outlet fumes temperature = 183 ºC
Conclusion:
Valid design, from the “fumes side”. Version suggested to AIC for the final HE’s CAD design.
Water side design not analyzed
Version 5
One row with 36 tubes at two different radii defined in the HE.
Tube geometry:
a=7 mm; b=5 mm; c=54 mm: d=64mm
Tube length = 150 mm
No fumes bypass tube: acting as a water distributor
Results from the CFD analysis:
Heat transferred = = 2.95 kW
Pressure drop in fumes = 1.7 Pa
Mean outlet fumes temperature = 116 ºC
Conclusion:
Good parameters agreement. Heat transfer higher than specified (2,5 kW). HE’s final design, from AIC, for the 3D CFD modeling (water and fumes side).
The designs were then assessed according to their performance against a variety of parameters. Namely these observations were against Heat Transfer (kW), Temperature of Outlet fumes (°C) and risk of condensation. The results provided following this assessment can be found within Table 4.
Table 4. Analysis of Proposed Heat Exchanger Unit Designs
Both versions 4 and 5 were able to successfully demonstrate the required characteristics. Taking the above results into consideration, along with a number of detailed conversations between AIC and the remainder of the project consortium, the most appropriate design to be explored further was Version 5. This was due its superior level of heat transfer of 2.95kW in comparison to version 4’s 2.21kW.
Figure 1 shows the preliminary CAD design of the HE, based on the results of the CFD modeling. This is then followed by Figure 2, demonstrating the AIC produced version of the first phase HE.
Figure1. Computational Image of First Phase HE (Version 5)
Figure 2. Photographs following production of the first Heat Exchanger prototype.
As there are many parameters affecting the stove and HE’s efficiency, several tests have been designed within the project, in order to check the performance of the system. The system was tested rigorously, utilising a range of conditions to obtain a clear view of the overall performance.
Tests were defined as follows:
Preliminary Stove Testing (Phase 1) –Such tests were designed to measure the stove’s efficiency under different wood load conditions (reference tests). This test was also repeated with different damper positions to check the influence of this parameter against the wood burning rate.
Combined Stove and Heat Exchanger Testing (Phase 2) – These tests would measure the total system efficiency under similar conditions as in the previously tested during phase 1. The overall purpose was to identify the operating efficiency of the HE system. As with phase 1, such tests were replicated by alternating the position of the damper component. Changes in the rate of wood burning were then assessed.
The first phase of testing, conducted with a purposely built heat exchanger unit, was undertaken with differing results. It was decided that improvements could be made surrounding the level of condensing created by the fumes and carbonaceous emissions. These processes were having the unfortunate effect of producing undesired tar and fouling within the HE. The most pleasing elements of the phase 1 tests were related to the thermal efficiency achieved, which was able to reach up to 80% during certain experiments. The resulting recommendations were summarized as follows:
• The HE must be re-sized: The first sample was oversized, with the dimensions of the fume tubes above the required level. This led to unacceptable levels of fouling. The removal of dimples within the fume tubes was suggested. The decision was also taken to utilize fewer tubes. Should this option be taken, the width of the fume tube would be increased.
• The damper feasibility is not clear: Significant drops in the level of fume pressure, along with severe cooling of the fumes within the HE significantly hampers the stove’s draught and combustion rate. Closing the damper had little effect. It was recommended that the damper could be removed for the purposes of combustion control.
• Cold Ignition of the wood is highly labour intensive, and can result in fumes/gasses entering the room where the stove is based. Potential options to explore included reducing the water volume within the HE.
• The current HE’s cleaning procedure is time consuming and excessive. Fume tubes were judged to be too small in terms of width, and along with dimples, reduced access to the required areas.
• Incorporation of a Fumes bypass would reduce ignition problems and fouling activity. Inclusion of a fume bypass was therefore recommended.
These recommendations were considered by AIC, with the support of Ikerlan following which a second version of the heat exchanger unit was produced. The final heat exchanger design is summarised within Figure 3.
Figure 3. Photographs of Phase 2 Updated Heat Exchanger
The HE’s main differing features are as follows:
• 15 fumes tubes, with 62 *11 mm2 dimensions (59*8 mm2 cross-section), and 175 mm length. Hydraulic diameter: 91 mm
• Total HE height: 386 mm
• HE’s active part height (between flanges): 290 mm
• Total cross-section in the 15 tubes: 6.500 mm2 (5.300 mm2, in the former HE1)
• Total heat exchanging surface: 195.200 mm2 (194.700 mm2 in the former HE1)
• Total HE weight: 13 kg.
The dimples (indents) within the tubes, used during the production of the first phase HE, were removed for the second phase model, this decision was taken in order to reduce the tendency to fouling within the fume tubes.
The second phase heat exchanger demonstrates three sections, each one with 5 fume tubes (right), and three fumes by-pass sections (left). Each section occupies 60 º of the HE top circular cover.
Our design then seeks a damper system installed above the HE. This is integrated with 2 mm space and connected to a step motor. As a result, this will prevent fumes passing by blocking the passage through the HE tubes or fume bypass. Partial blockage is also possible if required. Figure 4 shows the described damper actuator, enabling full or partial blockage of the tubes when required.
Figure 4. Damper actuator with the described modifications.
Finally, a window for visual access to the damper, as well as the supporting frame for the stepper motor, were added to the new HE’s top cover (Figure 5.)
Figure 5. New HE’s top cover with a window for visual access to the damper position
1.2 TEXTILE LINER
A core feature of the Intelli-Flue technology is the textile which will make up the chimney flue lining structure. Intelli-Flue is not solely about reducing expenditure on a financial level, but also promoting safety for European homeowners. This will be achieved through limiting the thermal energy transferred to the chimney walls to a maximum of 150°C, thereby significantly reducing the risk of fire. A primary danger of existing metallic (steel) flue lining systems is the level of heat that is transferred towards the surrounding structures. In some cases temperatures can reach up to 350°C, generated by flue gasses that can establish temperatures of up to 600°C. Assuming that this is the case we can assume a heat transfer rate of between 58 and 60%.
In order to meet the Standard Assessment Procedures (SAP), solid fuel stove burners have improved their combustion efficiencies during past decade, by using secondary and tertiary burners, which has significantly increased the amount of heat produced, and hence, the temperatures that the chimney liner is exposed to. Consequently, excessive heat is being transferred to the brickwork and surrounding building structures. The problems cannot be negated by operating stoves at lower temperature (inefficient combustion) as this will increase residue/condensate build-up in the flue which will further increase the risk of chimney fire.
The project objectives were therefore defined to seek a solution which enables the following:
• To limit heat transfer from the flue gases to brickwork or surrounding structure
• Thermal and mechanical sustainability for the temperature cycling of 5 °C to 750°C
• Liner flexibility (bend radii of 60 °C) to reduce installation time by 50 %
• Around 50 years of corrosion performance of flue-liner
Furthermore, the liner should:
The general system specifications will bring the following:
• Flue diameter: 155 mm inner diameter i.e. ¾ of store cross-section and a maximum outer diameter of 185 mm.
• Chimney is considered to have a square cross-section with sides of 225 mm and reduces to 200 mm at bends.
• Flue length of 10m is considered as the necessary length for the Domolab (test house) building. Bends with 40 º maximum. For a typical two story house flue length of 10 m and a maximum bend angle of 45 º.
• Pressure drop in the chimney: Natural draught not lower than 3 Pa under any conditions (according to the EN-13240). This is the pressure difference that needs to be retained to achieve no draught when stove is not lit.
• Typical life-time for existing ceramic flue liners is 25-30 years
• Operating liner temperature: 600 °C
• Outside liner temperature: 150 °C
• Flue’s thermal Insulation: Commercial double tube chimney with thermal insulation in between the tubes.
• Specflue’s ceramic liner has a ceramic layer thickness of 4 mm and can be used as a starting value.
The proposed flue liner is composed of four layers. As shown in figure 1, the innermost layer is made of a ceramic material and a three dimensional textile.
Figure 6. Cross-Sections of the Proposed Flue Liner Design
Primary Testing Procedure
The temperature cycle specifications for the liner testing are the following:
• Test 30 min @ 1100 °C: protect building in case of chimney fire, mechanical stability, Liner is replaced afterwards
• Test 4 h @ 750 °C is for max. operating temperature of 600 °C (Test name T600)
• Test 4 h @ 600 °C is for max. operating temperature of 450 °C (Test name T450)
Initial testing included a computational fluid-thermodynamics analysis which was carried out to assess the performance of the proposed flue liner design.
In order to understand how thermal characteristics of flue liner material affect the temperature distribution in the chimney, two types of analyses were carried out. The boundary conditions for the first analysis was defined by the industry standard conditions for testing to assess the capability of the flue liner to maintain integrity over a period of four hours while the flue gases are at 750oC.(Figure 5)
The second scenario was defined based on operational conditions where the exhaust gases were maintained at 100oC to represent the temperature at the outlet of the heat exchanger when it is operational.
When the exhaust gases were maintained at 750oC over a 4 hour period the temperature in the brick wall remained just below 150oC - thus complying with the safety requirement.
In the computational model an air gap was implemented between the outer wall of the flue liner and the brick wall. This results in a considerable reduction in the temperature of the wall. However, in practice, maintaining an air gap is not always possible unless the liner is specifically designed to maintain the air gap. It is therefore expected that the temperature distribution will be higher than predicted in figure 5.
When the backing insulation material was changed the resultant temperature distribution was similar for ceramic fibre and Rockwool and the highest chimney wall temperature with each material only showed a difference of about 1.6oC. With Microporous as the insulation material, it reduced the chimney wall temperature by about a further 10oC compared with the other two materials.
The temperature distribution through the brick wall under normal operational conditions with heat exchanger turned on and after a period of four hours is depicted in figure 6. The computational results show that the temperature of the brick wall remains below 30oC. Reduction in temperature across the flue liner is higher with when the backing insulation is Microporous when compared to Ceramic Fibre and Rock Wool.
Figure 7 – Temperature Distribution Along the Center-line in the Chimney after 4hrs Exhaust Temperature at 750oC
Figure 8 – Temperature Distribution Along the Centre-line in the Chimney after 4hrs Exhaust Temperature at 100oC
Computational fluid-thermodynamic calculations were carried out on a proposed flue liner design in order to analyse the performance characteristics with respect to geometry, materials and layer composition. The initial computational model composed of a thin section of a flue liner and chimney walls with an air gap between the two. It was found that this air gap to play a significant role in reducing the heat transfer from the flue gases in to the wall. The reflective layer however was found to be of low significance with regards to its effectiveness as a thermal barrier.
The computational tests carried out to investigate the thermal performance by varying the tri-layer combination thicknesses showed that a 1mm reduction of the air gap between the textile layer outer surface and the outer surface of the ceramic layer to cause a temperature drop of about 16oC across the flue liner. Whereas increasing the air component within the textile layer which is considered as a composition of air and e-glass showed an improvement of only about 0.3oC – 0.4oC in the chimney wall.
One of the baseline criteria for assessing thermal performance was the ability of the flue liner to maintain the chimney wall temperature below 150oC over a period of four hours while the flue gases are at 750oC representing the industry standard flue liner test conditions. The tests carried out showed that the proposed design is capable of satisfying this requirement. When the flue gasses were maintained at a standard operating temperature of 600oC, with all the tri-layer combinations the highest temperature in the chimney wall remained below 100oC.
1.3 CERAMIC FORMULATION
The Intelli-Flue project has pursued the objective to increase the consortium’s level of understanding surrounding the rheological and mechanical behaviors of ceramic materials. This was done with the view that this research could be applied in order to develop a suitable inner lining material which would be applied to the textile liner. It was important that the behavioral characteristics that could be attained would meet the necessary parameters in order to satisfy performance expectations within a domestic chimney environment. The preset criteria for the ceramic formulation were defined as follows:
• To maintain performance within a temperature cycling environment (5°C to 750°C).
• To develop a satisfactory level of impregnation between the ceramic material and the inner surface liner.
• Deliver 50 year anti-corrosion performance.
The project set out originally in order to develop a flexible ceramic material which would be applied to the textile liner prior to application. However, the first period of the project saw the undertaking of a number of analysis and testing exercises which determined that this may not be possible. The principle reasoning behind this was that the storage and hence workability of the ceramic (limited to 14 days) and the transportation complications that would be incurred through such an approach. The decision was therefore made that an in situ application method would be explored.
It was therefore necessary that research was directed towards a ceramic formulation which could provide the correct workability which could be applied following installation of the textile liner. Different methods of ceramic application process would be assessed for their viability. The three methods identified within this project are manual pasting, pouring and spraying.
2. MATERIALS, COMPONENTS AND STRUCTURE
2.1 HEAT RECOVERY SYSTEM
The Intelli-Flue heat recovery system is comprised of 3 ‘sub systems’ which when combined are able to provide a complete solution. The 3 elements to be considered are the heat recovery, closed circuit and control systems. Figure 9 clearly shows how these are combined within the prototype set up.
Figure 9. Demonstration of the Sub System Lay Out
The Heat Recovery System is the main sub system in its own right. The heat from the fumes is then transferred directly to the water circuit. The system specifications are detailed as follows:
1. The heat exchanger, with the fumes damper, the stepper-motor support frame and the windows in its top cover providing access for mechanical cleaning
2. The stepper-motor: 42 mm, 44 N*cm 0.9 deg. 2.8 V, from RS
3. The mechanical damper rotation system
4. The connector of the stepper-motor with the mechanical damper rotation system, allowing for some misalignments of the motor axis and rotation system axis: Double Loop Couplings with Steel Hubs
5. Double Loop Couplings with Steel Hubs
6. The outlet fumes temperature sensor, placed downstream the fumes damper and in a “radial” location: presently a K type TC, but could be substituted by a NTC with the range 0-300 ºC.
7. The inlet water temperature sensor, placed in the top water connector: presently a T type TC, but could be substituted by a NTC with the range 0..120 ºC
8. The outlet fumes overheating thermal switch (On-Off), located downstream the fumes damper and in a “radial” location
The water overheating switch (On-Off), located in the top water connector.
The next sub system to be considered is the Closed Circuit system. This component is responsible for the integration of the Intelli-Flue technology towards a domestic heating system. The general purpose is to make the transfer of heat energy into the house possible, whilst eliminating the risk of cold water entering the heat exchanger during the stove ignition process. This would have significant negative impact through the production of condensation and tar occurring within the fumes tubes. The proposed system will include:
1. Metallic supporting panel, to make the closed circuit system installation easier.
2. Circulation water pump: UPS 15-30 130
3. Circular Expansion Vessel
4. Hydraulic connection circuit-expansion vessel
5. Safety Valve
6. Air Purge
7. Water Pressure Gauge
8. Circuit Draining Tap
9. Thermostatic Three-Way Valve, with 60 ºC set-point.
10. Flexible high temperature hoses connecting the HE with the closed circuit system.
11. High temperature flexible tube for the potential water vapour discharge from the safety valve to the drainage system.
12. Raccords and copper tubes.
Finally, the control and automation system will provide sufficient monitoring opportunity for the end user of the Intelli-Flue system. This will consist of a multi-functional display unit, enabling full control within an aesthetically pleasing manner. Typical inclusions within the planned system will also include, but may not be limited to the following:
1. A multi-function display
2. A reset button for resetting the accumulated stove’s working hours.
3. A yellow pilot: for an “alarm situation” indication
4. A buzzer, for “severe alarm situation” indication
5. A battery based, independent safety system for activating the buzzer in case of an alarm situation (even under mains blackout). Connected to the thermal switches.
6. Cables for connecting the sensors and actuators in the previous subsystems
Table 5 outlines the performance of the Intelli-Flue Heat Recovery system against those plans originally set out within the end user requirements. As can be seen on the table, all the values obtained with the system developed are significantly better than the values initially specified for the process variables.
Only the diameter finally defined is longer than initially specified, but this is largely compensated by the reduction on the other HE dimensions, and the significantly lower HE weight.
Table 5. Comparison of Performance against Initial Targets for the Heat Recovery System.
VARIABLE SPECIFIED VALUE REAL VALUE IN TESTS
Maximum allowed HE height 600 mm 386 mm
Maximum allowed HE diameter 225 mm 300 mm
Maximum allowable HE weight 20 kg 15 kg
“HE+ stove” efficiency range 70-80 % 79 ºC
HE’s minimum thermal efficiency (with 50% eff. stove) 25 % 35 %
Minimum average fumes-water heat transfer rate 2.5 kW 3.5 kW
Maximum operating fumes temperature in the chimney 300 ºC 200 ºC
Natural draught, in the chimney > 3 Pa > 10 Pa
Pollutant emissions, CO, in fumes (at 13% O2) < 1.0 % < 0.8 %
2.2 TEXTILE LINER
The performance of the chosen textile will have a direct impact upon the overall performance of the Intelli-Flue liner. Each layer is required to contribute the desired characteristics such as temperature performance, flexibility, memory shape and structural credibility. An array of potential textile materials was considered throughout the design phase. Table 6 highlights those potential options considered, along with their performance characteristics.
Table 6. Analysis of Possible Fibre Materials
Having successfully conducted this analysis, the potential combinations of materials were discussed. As originally highlighted within Deliverable 1.1 these were defined as follows:
• AR-glass fibre with PTFE fibre, this can be the best combination because both of them have good corrosion resistant properties, good working temperature and also by combining both of them low tenacity of the PTFE fibre can be compensated.
• S 2 glass fibre definitely has better properties than AR-glass fibre but it is expensive. S 2 glass fibre can be combined with p-Aramid fibre; this combination is also good combination by exhibiting the properties very near to the requirements.
• PBI fibre with PBO fibre, both fibre material exhibits good corrosion resistant, fire resistant and good working range. The tenacity of PBI material will be compensated by PBO material.
• PI fibre with Polyester fibre, this combination has good working temperature range, corrosion resistance but their tenacity is not good. This combination is chosen because PI fibre is expensive and Polyester fibre is cheaper one so the price can be compensated.
The planned deviation from a pre impregnated liner, to in situ ceramic application means that the liner construction must be favourable towards spray application. The structure of the textile liner contains three single parts. The nonwoven on the inside of the liner allows a closed textile surface. That`s important for the in-situ application of the spraying system. The ceramic application needs this element as a base structure.
The second part is the 3D-spacer fabric which creates an air gap with a thickness of 10 mm. This provides a good functional insulation. A braiding or another nonwoven surface completes the structure on the outside. This textile element provides a fixation of the geometrical shape and protects the textile liner during the injection process into the chimney.
The final construction for the proposed Intelli-Flue liner is summarised as follows:
• Internal basalt 3D fabric with vertical stubs
• Double layer of Basalt non-woven material.
• 25 mm X 25 mm basalt geogrid with bitumen coating
• Glass Overbraiding
If required, the vertical flexibility of the liner can be adjusted through changing the dimensioning of the geogrid. This is likely to improve the performance of the liner in terms of reducing the risk of any potential ‘kinks’ forming during the installation process. This is especially necessary for installation in complex chimney stacks. It is suggested that when horizontal stiffening is closely spaced, this will provide greater flexibility in the liner. Hence, in the case of Intelli-Flue, it would be possible to change the existing style of geogrid from a square to a rectangle with closer horizontal stiffening as compared to the existing geogrid (i.e less than 25mm) and further vertical stiffening (i.e greater than 25mm).
2.3 CERAMIC FORMULATION
The resulting ceramic formulation is accompanied with an easy handling and processing technique which will maximise the efficiency at which this material can be applied. The material can be transported and stored in a ‘dry mix’ state, to which water can be added, along with the required accompanying liquid state components. This is then mixed with the use of a paddle mixer, or equivalent for a short period of time, before being applied by the chosen method.
Within the Intelli-Flue project, the consortium has been able to define that the most appropriate method of application will be spray. However, it is clear that there is still a proportion of further development work that will be required in order to fine tune this application process. The spray head to be used will need to be matched in terms of capability against consistency of the mixture, viscosity and flow rate. This will maximise the mechanical bond between the ceramic and the inner textile liner.
The chosen ceramic formulation selection was the result of an extensive analysis of over 30 samples. The Intelli-Flue project has clearly demonstrated the potential and capability in terms of performance for the ceramic formulation. The chosen sample has undergone extensive testing within a real life chimney environment, showing no signs of cracking, corrosion resistance or void development.
The project has also made significant attempts to produce an integrated solution, attempting to coat the textile liner with the chosen ceramic slurry. Three application methods have been explored within the project, manual pasting, pouring and spray application. Out of those tested, it would appear that spray application is likely to be the most viable application method within a commercial environment. However, the process for completing this is still under investigation within the consortium. The mechanical bond between the ceramic and the textile is judged to be of an appropriate standard. However, ensuring an even layer of ceramic across the entire length of the liner is proving challenging. This will be investigated further following completion of the project.
It should be stated, however, that the development of a suitable formulation has been successfully achieved, and it has been confirmed that spray application is possible with the consistency of the ceramic slurry developed. We therefore propose that with a small quantity of further development work, we can succeed in the development of an acceptable solution for introduction into the commercial market.
Potential Impact:
1. INTRODUCTION
Once introduced into the commercial arena, Intelli-Flue will have the potential to generate a substantial positive impact, both commercial and technical. The overall technology represents a number of sound technological advances, which when combined with the commercial potential, create an exciting opportunity for our consortium members, and a valuable solution for our target customers. In order to truly assess the socioeconomic impact created, it has been necessary to pay special attention to the quantitative and qualitative measurement of impact.
Table 2. demonstrates the sales forecast that has been created for the Intelli-Flue technology. This forecast is based solely on new system installations.
Table 2. Sales forecast for the Intelli-Flue Technology
Year Number of Intelli-Flue Systems Projected to be Sold (entire system) Size of Market (Number of Units Sold per Annum) Total Market Penetration (%) Revenue Achieved (€m) Planned Profit (€m)
2014 400 2,000,000 0.02 1.32 0.25
2015 2050 2,050,000 0.1 6.76 2.60
2016 6303 2,101,250 0.3 20.79 4.87
2017 8615 2,153,781 0.4 28.42 7.22
2018 11038 2,207,625 0.5 36.42 10.00
*Assumptions:
A market growth rate of 2.5% per annum.
Intelli-Flue selling price €3,300
We anticipate that the Intelli-Flue product has great potential to assist our consortium members in growing their own business. In addition, our network organisations (to be identified to aid installation throughout Europe) will also have the opportunity to pursue growth. The additional revenue to be attained by the consortium as a whole will lead to the creation of up to 75 new jobs. This assumes 1 new post generated per €100,000 profit generated. Furthermore, there will be an additional 30 new jobs created within our network partners/suppliers (Assuming a minimum of 2 people per member state, within the 15 largest markets for Intelli-Flue.) These forecasts are assuming a very conservative market penetration level, only 0.5% within the 5 years post project. It is therefore highly likely that these figures can be exceeded, and the commercial performance of the Intelli-Flue technology improved even further.
Figure 1. Sales Forecast for the Intelli-Flue Technology
Figure 2. Revenue Forecast for the Intelli-Flue Technology
The forecasts provided take into consideration that full commercialisation will take place in 2014, and then project the following 5 years’ sales. It has been assumed that total profit available from the sale of a single unit will increase with the economies of scale available through mass production. In summary, profit per unit will vary between 5% (2014) and 20% (2018). Sales and revenue forecasts are demonstrated graphically within Figure 1 and Figure 2 respectively.
3.3 Unique Selling Points to Provide Commercial Success
Both components of the Intelli-Flue technology (Liner and Heat Recovery system) have defined unique offerings that set them apart from competitive products.
3.3.1 Flexible Textile Liner System
• Reduced Insurance Premiums
The Intelli-Flue system provides potential to significantly reduce insurance premiums – Insurance companies have been taking measures to reduce the risk of paying out by using premiums or high insurance quotes for properties that have not used industry approved fitters/installer and are deemed to be at risk.
Specialist insurance firms for thatch houses currently provide a variety of incentives for customers using certain installers/technologies/equipment which can reduce the overall risk of fire caused by poor chimney maintenance. For example, NFU mutual will provide discounts on insurance premiums if Magma Fire Stop or Thatch Firewall has been installed during the past 5 years. Such schemes provide customers with an incentive to take up new technologies, designed to reduce the overall risk to the insurance provider. Some Insurance companies will no longer pay out for chimney fire damage unless the flue has been swept and maintained by a professional chimney sweep who can issue a valid certificate of sweeping recognised by the insurance companies themselves.
The Intelli-Flue consortium will seek to open discussions with underwriters in a bid to offer similar incentives through installation of the proposed system. This will not only increase the market potential for Intelli-Flue, but also assist towards reducing the overall number of claims made due to chimney fires. Affordability is also improved for the end customer.
• Ease of Installation
The ease of installation for the Intelli-Flue technology is significantly improved compared to that of competing pre-fabricated flue liners. We anticipate that the entire installation of the Intelli-Flue system will take place within 1 working day. This is comparable to existing single-wall, flexible steel flue liners, which are less than ideal solutions as previously stated within this report. Cost of installation will be lower (liner and installation will cost approximately €1600) thereby representing improved value to the final customer.
3.3.2 Heat Recovery System
• Improved Energy Efficiency
Generally speaking, the efficiency of domestic stoves is well below 50%, with most stoves reaching a maximum of 30% efficiency during general use. This is due to the high level of heat energy lost up through the flue. Our latest project results have suggested that we can improve this through implementation of the Intelli-Flue technology towards 85%. This will lead towards significant cost savings for the customer, reducing their overall energy bill. It is our intention to strive towards a total payback period, covering the cost of installation, of 5 years. This will be reliant upon the reduction of manufacturing cost through incorporating economies of scales as the demand for the Intelli-Flue product increases. However, as a consortium, we feel that this is achievable nonetheless.
Thatched Owners Group represents over 1 million homeowners throughout Europe. During a recent survey it was reported that only 2% of stove owners had their stove connected to a boiler system. Of those who did not, an overwhelming majority responded positively towards the Intelli-Flue product suggesting that it may be of interest, and something that they would be prepared to explore further. Payback period and overall bill reduction were considered as two things that were most important to potential customers. This feedback is extremely complementary towards our technology, and sets a sound target audience for the technology in the short term future.
Our consortium members represent leading organisations, working at the top of their industry. Their client base spans the majority of European member states, and their supply chains create an array of organisations, including multinationals, medium and micro enterprises. Combined, Intelli-Flue is demonstrating the combination of transnational commerce, encouraging interaction between small, medium and large enterprises.
Within this Final Report, our consortium has taken the opportunity assess the impact of our technology, taking into consideration the thoughts of our partners, their customers and the surrounding stakeholders.
As outlined within our original funding application, our project consortium has always maintained that there is a clear need for an efficient heat recovery system for operation within a domestic environment.
We propose that the monitoring of the socioeconomic impact should be a continuous activity, and that this can take place at regular intervals (every 6 months) following the completion of the project.
2. DEMONSRATING SOCIAL IMPACT
Intelli-Flue has the potential to deliver a series of wider benefits throughout the European Community. The following section will seek to analyse these and provide a summary of the potential impact.
2.1 Providing a Contribution towards Decreased Levels of Fuel Poverty
Levels of fuel poverty throughout Europe are increasing. Typical fuel poverty is demonstrated when the home is cold, thereby presenting an unhealthy environment for the habitants, or when fuel debts accumulate. This is a topic that is currently debated at a high level across Europe, stimulated by increasing fuel prices and falling levels of disposable income within European households. It is suggested that within the United Kingdom, approximately 10% of households have fallen in to the category of fuel poverty; a similar statistic is echoed in Spain, Germany, Netherlands and Sweden. Even high levels, in excess of 20% are found in Poland and Lithuania with the highest level of fuel poverty registered in Portugal where 1 in 3 homes are detailed as struggling to heat their homes.
In 2000, the UK introduced the Warm Homes and Energy Conservation Act. This represents a parliamentary passed target for the reduction of the level of fuel poverty. This strategy included improving the energy efficiency of homes, seeking to reduce overall fuel consumption and therefore reduce levels of vulnerability to fuel poverty. Results were initially positive, reducing the number of households in fuel poverty during a period when energy prices were stable. However, since 2004, this trend has reversed due to fuel price increases. This is evidence that there remains very little tangible support for those households attempting to tackle fuel poverty. However, in 2013, the UK remains the only country to present such a measure. European households are struggling to maintain a comfortable living environment, caused by a lack of heating and lighting within the home. A major concern is that this occurs in line with a period when Europe seems to be susceptible to some of the most extreme winter weather conditions witnessed for a number of decades.
There are a range of health impacts that can be witnessed by habitants living in cold homes. This is supported by the Marmot Team Review (2011) which states that there is a direct link between poor health and living in a cold home. Fuel poverty places extreme pressure upon the lives of a range of people. It is not only related to physical illness but also mental health. This is thought to be caused by the financial trauma that is implied upon households attempting to tackle the rising debt and other problems associated with fuel poverty.
2.2 Seeking to Achieve Increased Levels of Fuel Security in Europe
European media sources are continuously promoting the vulnerability of European citizens due to the instability of the energy markets. Prices are fluctuating on a regular basis, with the general trend indicating price rises.
A resulting scenario is that consumers are increasingly prepared to consider alternative sources of heating and/or lighting within their homes. One such solution which is proving increasingly popular is the use of solid fuel burning stoves. This is reducing the dependency from homeowners on the most common forms of heating such as gas central heating/oil. Dependency on such fuels, produced through utilisation of finite resources, has produced a detrimental effect upon our surrounding environment, following decades of excessive and increasing levels of use. It is true that there are still supplies of oil and natural gas in existence, but the rate at which their use is rising, far exceeds the rate at which new supplies are being identified. Should the level at which the European Community, and indeed the Global economy is utilising such finite resources continue to rise, statistics suggest that both oil and gas reserves could be extinct by 2068.
In summary, we can confirm that the level of fuel security throughout Europe is put at risk through the following occurances:
Exhaustion of Energy Source – Oil and gas reserves are a limited resource, and their levels are falling. In addition, 90% of world reserves are controlled by firms based within the Middle East and Eurasia.
Economic Risk – Energy products are subject to extreme fluctuations in price. Supply and demand can cause prices to rise suddenly in short spaces of time, which can significantly impact the energy market suppliers in Europe, with price rises being passed on to the end consumer.
Geopolitical Risk - Government decisions to suspend deliveries of oil and gas because of policy, war, and/or terrorism can put supplies under significant threat. This has become over more apparent during the past 2 years with a number of uprisings threatening the supply to certain parts of Europe.
By improving the safety of solid fuel combustion and enhancing the efficiency of solid fuel combustion through energy recovery, Intelli-Flue will encourage Europe to increased solid fuel usage helping Europe to meet renewable energy targets by offsetting current dependence on oil and gas.
It should be noted that the positive impact of the Intelli-Flue technology is not only restricted to the monetary benefits available to the consortium and the end user, but also safety. We propose that the installation of an Intelli-Flue unit can substantially decrease the level of risk presented to a home relating to chimney fires. The severance and likelihood of chimney fires is often not considered by many households to be high. However, recent figures are stating otherwise, with the level of chimney fires increasing heavily during the past decade. It is thought that approximately 200,000 domestic fires per annum are the result of a chimney defect. Taking this into consideration, each and every European household with an operating chimney should seek to have regular maintenance checks conducted by a qualified chimney engineer. A report provided by the European Federation of Chimney Sweeps suggests that a survey conducted in 2010 indicated over 1 million defects in already existing chimneys, with a further 117,000 faults in newly built ones. Such faults represented a substantial risk towards fire safety. Such levels are not acceptable.
The Thatched Owners Group, coordinator of the Intelli-Flue project, has an existing relationship with the UK Fire Service. They have conducted a range of ‘road shows’ which promote regular chimney maintenance, and its effect on reducing the risk of chimney fire.
2.3 Preservation of European Heritage and Culture
The market potential for the Intelli-Flue technology is further enhanced by the fact that applications reach out to not only domestic homes, but also commercial buildings and historical sites (manor houses, heritage sites, period homes etc.) The perceived need for such a solution is further enhanced by the fact that a number of high profile heritage properties have suffered from the effects of a chimney related fire during 1992 alone ; Christianborg Palace Church, Copenhagen, Windsor Castle, Berkshire, England and Redoutensal, Hofborg Palace, Vienna.
Listed, period homes and heritage sites are in particular danger given the use of thatch and timber as traditional building materials. Given the significant number of heritage buildings and historic towns across Europe the potential for loss from chimney related fires is significant. We propose that wherever possible, this risk should be reduced.
2.4 Pursuing Confidence in Alternative Technologies
Consumers often demonstrate a degree of reluctance before pursuing the uptake of a new technology, especially those which require significant investment, substantial structural work and are untested within the market. Intelli-Flue has therefore taken careful steps to overcome these barriers and present a solution which encourages take up by the final customer.
There is currently a large amount of research being conducted, as well as product development activities which is seeking the introduction of new technologies which support the reduction in energy expenditure within European households. However, it is fair to suggest that considerable effort will be required in order to bridge the gap between product development and introduction into the marketplace. We maintain the opinion that the Intelli-Flue technology represents a novel solution to a highly publicised market need within the European Community.
Manufacturers must seek to encourage consumers to invest in alternative technologies, as well as allowing for the installation within their home.
There is also an ancillary argument which calls for the support of European governments in introducing such technologies to the market. This can come in the form of subsidies or grants and/or incentive schemes which promote the demand for new products. This can also act as a valuable marketing tool in promoting the technology to a wider audience. Recent efforts have taken place in the form of ‘Energy Smart Meters’ and ‘Solar/Photovoltaic Panels.’ Uptake has been promoted through the use of preferential rates/pricing strategies; however, impact in overall consumption has been so far been limited.
Intelli-Flue represents something different; no longer does the focus have to remain upon cost and ‘green’ credentials. We have now created a third dimension which could be considered to be the most important of all, that is increased safety to the end user. As the level of sales for solid fuel stoves continues to rise, the importance of safety and chimney maintenance will be of paramount importance. Intelli-Flue can have a leading role to play in the mission to improve the level of chimney condition and safety over the coming 5 years. Through being affordable, easy to install, and able to be retrofit to existing chimneys, our solution overcomes many of the barriers presented by existing attempts to lure customers towards alternative green technologies.
3. DEMONSTRATING ECONOMIC IMPACT
3.1 Progress through Collaboration
The Intelli-Flue technology is the result of a successful collaboration between a consortium of commercial partners on a pan European level. The transnational approach to this project has enabled varied points of view to be taken into consideration, incorporating a variety of cultures and legislative patterns represented by those countries involved within the project. It could also be suggested that this has allowed for a more thorough assessment of the market need.
It should be well publicised that the results so far created by the Intelli-Flue project are the result of a productive collaboration. Furthermore, there have been a range of indirect benefits that have been made available to the project consortium. The networking opportunities presented within the project have led to a number of commercial transactions for those involved, some within the consortium and some further afield within the European business community. The knowledge generated within the project has also enabled the further development of existing products within a number of consortium member’s product portfolio. This will lead to a unique offering which can provide a competitive advantage, benefiting the project consortium member even further.
If replicated, we propose that this could have a positive impact on the wider EU business community. There have been many studies conducted in relation to the impact that collaboration can have towards creativity and innovation. The bringing together of different levels of expertise, the inclusion of personnel from different hierarchy levels as well as representation from a range of industries, has enabled the project consortium to engage in a number of productive and thought provoking conversations throughout the project. The result from this is a large proportion of valuable knowledge exchange between partners, allowing for application not only within the Intelli-Flue technology but also within their individual businesses.
Such collaborations offer an array of networking opportunities, which enable those involved to maximise their benefit through being associated with the project. The success of the Intelli-Flue project has the potential to increase the appeal of European Commission financed partnerships which in turn could lead to an increased throughput of novel technologies for the future.
3.2 Direct Benefits for the Intelli-Flue Consortium
A clear commercial business case has been set up within the Intelli-Flue consortium, ensuring direct economic benefit to the consortium members. The impact of this benefit, however, will be realised on a wider scale, as suppliers, customers and the surrounding environment realise clear advantages within the short/midterm (up to 5 years post project).
Our data is calculated assuming that the current level of sales for domestic stoves totals 2 million units per annum. This figure is expected to increase steadily has consumers seek a cheaper alternative to gas/oil based central heating. For the purposes of illustration, based on our consortium knowledge of the market, we propose an annual growth rate of 2.5%. The Intelli-Flue consortium has therefore made a conservative target to achieving a market penetration rate of 0.1% within the first 24 months of production. This represents sales of 2450 units. It is important to note that this figure only relates to new stove installations. In addition, a target has been set to achieve a further 2000 sales through retrofit systems to existing chimney/stoves. It is thought that these targets are achievable based on the networks possessed by the project consortium, along with the extensive marketing and dissemination techniques to be conducted alongside the launch of the Intelli-Flue technology. These are detailed within the project’s Dissemination and Use Plan.
Assuming an average sale price of €3,300 for an entire system, this will represent total revenue in excess of €2million generated from the Intelli-Flue product within the first 24 months post project. The consortium has taken into consideration that revenue and profit levels will be affected by the fluctuation in price of raw materials/manufacturing costs.
The project consortium can also benefit through a number of additional ‘bolt’ on services that will be sold in partnership with the Intelli-Flue technology. For example, a comprehensive, after sales service package. It is already planned that these services will be offered by TOG in partnership with CICO for UK installations. Discussions with European network partners are also on going.
As take up of the technology proceeds, and identification of future Intelli-Flue branded products becomes available, it is thought that further commercial benefit can be realized. We therefore suggest that the commercial figures projected are somewhat conservative, and certainly achievable within the timescales provided.
List of Websites:
www.intelli-flue.eu
Having commenced in February 2011, the Intelli-Flue project set about the development of a novel energy recovery system, combined with a state of the art protective flue liner. The project lasted for a duration of 2 years.
The vast majority of European homeowners live in a property that has an operational chimney. A large number of consumers assume that a functional chimney, used regularly over a number of years, will represent little or no threat to their safety. The unfortunate reality is that poor chimney maintenance can be the cause of significant injury or even death, due to the threat of chimney fires. There is currently a noticeable lack of awareness amongst consumers, and as a result, chimney integrity is not questioned until after a fire.
Processed and poor quality solid fuels produce highly corrosive flue gases that significantly reduce the lifetime of flue liners. Such fuels are often marketed as being highly reliable, more efficient and cheaper than seasoned alternatives. Additional risk is posed by increased flue gas temperatures from high efficient solid fuel stoves, flue liners are failing to reduce serious chimney fires.
The Intelli-Flue project has been conducted by a highly committed consortium consisting of 6 Small to Medium Sized Enterprises (SMEs), supported by 3 European research institutes. Each member has contributed whole heartedly towards the development of the Intelli-Flue solution. When combined, the expertise within the consortium has aided the project to move towards a commercially viable solution, overcoming a variety of technical challenges within the lifetime of the project.
The Intelli-Flue solution provides a solution to address the issue of highly corrosive flue gases and elevated flue gas temperatures by developing a protective ceramic liner, with increased durability performance, alongside a novel heat recovery system. This will enable domestic stoves, old and new, to burn efficiently, harnessing any waste heat for use as a source of domestic heat. Additional benefits include limitation of flue gas temperatures, and thus the risk of chimney fires. The combination will enable homeowners to continue to use solid safely without risking the building and its occupants.
The Intelli-Flue products can save money. It is not a luxury item. The Heat Exchanger saves the end user money on the most expensive part of any household expenditure, heating. The Intelli-Flue liner has the potential to save our customers money on their home insurance policies. Maintenance costs could be reduced, and lifespan of the product substantially increased. Intelli-Flue promotes solid fuels as alternatives to oil and gas for the purposes domestic heating. With concerns over energy supply set to continue, Intelli-Flue will help Europe to better utilise solid fuel resources and diversify our energy mix, assisting the European Community to meet EU energy targets.
Project Context and Objectives:
The Intelli-Flue project consortium was successful in obtaining funding support from the European Commission, within the funding programme Research for the Benefit of SMEs, to support our ambitious, yet highly innovative development project. The project commenced during January 2011, and lasted for a period of 2 years. During this time, we have set out to investigate the proposed objectives, through a combined effort of our consortium members. The Intelli-Flue consortium consists of 6 SMEs, representing 5 EU member states. This transnational approach has been of significant value to the consortium, with regular interaction taking place between all parties, a number of business opportunities, external to the project have already been explored. The consortium has employed the services of 3 research performers, UK Materials Research Institute, Ikerlan and Aachen University. Throughout the project, the technical contribution made by our researchers has enabled the SME supply chain to focus heavily upon the commercial elements of the project, detailing production plans and exploitation strategies that will see the Intell-Flue product taken to market following a successful delivery of the initial research project. The consortium is buoyed by the results provided within the first stage, and has consequently submitted an application for a follow-on project, which would address the demonstration and fine tuning of the Intelli-Flue product. If successfully granted, this project would be financed under the European Commission’s ‘Demonstration Activity’ funding.
The history behind the development of the Intelli-Flue concept is the result of a wide variety of contributions from industry leaders within the field of chimney maintenance, insurance and building services.
With concerns over energy supply set to continue, consumers are looking for sustainable, price resilient alternatives to oil and gas. At present, the most likely candidates to provide an alternative are solid fuels such as biomass (wood). It is possible that even coal can be considered following the latest new findings within the UK and across Europe. European countries are promoting the better utilisation of solid fuel resources in an attempt to diversify our energy mix to meet pre-set EU energy targets. Solid fuel stove burners have potential to achieve 75-80% combustion efficiency enabling solid fuels such as wood, energy crop and coal to be viable domestic heating alternatives to oil and gas. As a consequence, solid fuel stoves’ sales are on the increase; however, with increased domestic solid fuel use there has been an increase in stove/chimney related serious house fires. It should be considered, however, that the efficiency of the vast majority of stoves on the market today is heavily limited. This could be due to poor installation, unfavourable fuel selection and less than optimal operating conditions. Market knowledge within the consortium suggests that the level of efficiency provided by most stoves is closer to 35/50%.
The quality of the fuel being combusted is a major contributory factor to chimney related fires. At Thatched Owners Group Ltd (TOG) we are seeing unseasoned/poor quality fuels and in particular, processed solid fuels producing highly corrosive flue gases that are significantly reducing the lifetime of flue liners (sulphur and chlorine mixtures from condensates reacting with moisture to produce acidic complexes). In some instances corrosion has resulted in rapid failure within 5 years or less, despite manufacturers claims of a life of 25 years. As steel has a high thermal conductivity, it is subject to rapid cooling when the fire in the stove is dying out, promoting condensates to form which lead to corrosion attack on the metal.
The proposed concept will not only enable the consumer to increase the level of safety, and efficiency within their home but also contribute towards the following EU policies:
European Energy Consumers Charter
Energy Performance of Buildings
EU Biomass Action Plan
Kyoto-Target CO2 Plan
Chimney safety is currently a well debated topic at pan European level, with legislation under review across the majority of the EU27. Intelli-Flue can contribute towards improved safety measures, and represents a cost effective solution for a real life problem. To compound the problem, high-efficiency solid fuel burners (secondary/tertiary burn) coupled with consumers purchasing stoves based on grandeur and size means today’s installed stoves are over-specified. Increased flue gas temperatures lead to the potential for heat transmission through the chimney to the building and any combustible materials used in the building construction (e.g. wood timbers and/or thatch).
Intelli-Flue originally set out to develop a solution for a flexible ceramic flue liner that enables easy installation at an acceptable cost for the end-user. This would prevent the corrosion problems presented towards metal flue liners when poor quality, corrosive solid fuel is used for domestic heating. A solution that aims to reduce fire risk to a building and its occupants will also address higher flue gas temperatures from today’s highly efficient stoves. Following initial stages of research and development, the consortium discovered that the development of a pre-impregnated liner, comprising of a flexible ceramic liner, would not prove to be a commercially viable option. This idea was hampered significantly by the mid/long term storage process of the liner, the transportation methods available and the curing process required following installation into the chimney. The project therefore made a deviation, still maintaining the original objective to create a refractory ceramic formulation with much improved properties compared to those available on the market today. This would then be applied in situ.
The second component of the Intelli-Flue product is a state of the art energy recovery system. It is suggested that up to 75% of the heat energy produced within a stove is lost to the flue. This energy represents lost potential which is deemed useless. Our heat recovery system will provide the opportunity to recirculate this energy within the home’s domestic heating system. The Intelli-Flue project will deliver improvements in both thermal efficiency to be achieved by the stove as well as user comfort and assurance. Current solutions are haunted by the fact that they are either not aesthetically pleasing, or they require constant operator attendance. In today’s modern era, this is not acceptable, nor commercially viable. Substantial efforts have also been made in order to ensure maximum safety performance within the system, providing reassurance to the end user that the risk of overheating is minimised. This is aided by the development of a comprehensive combustion control system within the project. Combined, the project was setting out to achieve actual thermal efficiency for the stove of up to 90%.
The integration of the Intelli-Flue heat exchanger module will also assist in limiting the temperatures of which the flue liner shall be exposed. This will be possible due to the fact that energy is transferred to alternative uses such as heating rather than direct exhaust through the chimney.
In summary, the Intelli-Flue technology is made up of 3 core developments (areas of research focus), each presenting their own objectives that needed to be achieved within the lifetime of the project. A summary of these and their associated objectives can be found below:
Heat Recovery System
Develop fumes/water heat exchanger designed to limit flue gas temperatures to a max. 750°C.
Develop an air damper to modify and establish the potential for adaptive combustion control.
Establish waste heat recovery performance characteristics.
Integrate a waste heat recovery system and liner to evaluate energy recovery performance. Deliver 70% heat exchanger efficiency.
Textile Flue Liner
Define liner construction to limit heat transfer from the flue gases to brickwork/surrounding structures to a maximum of 175°C.
Develop liner flexibility (bend radii of 60º) to reduce installation time by 50% compared to current ceramic/clay systems.
Deliver 650°C liner operation (operating limit of 750°C) for 4 hours. Contain a flue fire 1100°C for a minimum of 30 minutes [BS EN 13063 part 1].
Ceramic Cement Formulation
Develop ceramic-cement formulation to deliver corrosion performance for acidic (pH2.5) flue environments.
Develop ceramic-cement formulation to cope with temperature cycling (5°C to 750°C) and for impregnation into the inner surface liner.
The Intelli-Flue project has sought to produce a cost effective, responsible solution to meet the challenge of improving the safety and viability of domestic heating via the use of solid fuels. The project has developed a range of novel innovations which represent a valuable commercial opportunity for each of the SME consortium members. These are summarised by the following:
• Textile Liner Design
• Textile Manufacturing Process
• Heat Exchanger Design
• Ceramic Cement Formulation
• Combustion Control System
The use of poor quality fuels on domestic stoves represents an extremely harsh environment for the surrounding features. For example, the temperatures produced within a domestic stove can reach in excess of 600 °C, with acidic gasses reaching extremes of pH2 in some cases. This is caused as a result of the sulphur and chlorine gasses given off by a range of fuels. It is therefore imperative that the Intelli-Flue liner system is capable of operating within these conditions. Such temperatures pose a significant threat to external structures, for example exterior brickwork, wooden beams or straw thatch, which when exposed to such temperatures can have a tendency to catch fire. This poses a significant risk to habitants and surrounding homes. We have therefore ensured that the textile liner incorporated within our system limits the heat transfer from the interior layer to the exterior fabric, with the resulting exterior temperature being less than 175 °C.
The Intelli-Flue liner will deliver the following characteristics:
• Corrosion resistant lining – abrasion resistant surface (for sweeping) that will contain flue gases at elevated temperatures and in a highly corrosive environment.
• Highly insulating liner – minimise heat transfer to the chimney and surrounding structures.
• Flexible circular liner construction – deliver uniform insulation (no seam or ‘weak point’ for heat to be conducted through) and introduce easy installation.
Project Results:
1. DESIGN AND SPECIFICATION
1.1 HEAT RECOVERY SYSTEM
Heat energy provided into the home through combustion of the wood/fuel is generally provided through radiation. Small quantities of heat are also provided by the natural process of convection. Most stoves, when in operation, are able to return a thermal efficiency rate of up to 50%. The Intelli-Flue consortium can therefore conclude that the heat energy lost to the chimney is significant and should not be ignored.
User comfort is also of paramount importance for any such technology entering the domestic heating market. Throughout the project this has been at the forefront of discussion, and where possible acted upon to be incorporated into our final design. Domestic stoves are generally viewed as being simple heating systems, with a manual method of controlling thermal power. This is typically achieved through varying the wood feed rate and/or adjusting the chimney’s draught level. Stoves within the global market today can also be noted as having very little potential for heat recovery. Existing systems require continuous human attendance, which in a modern era is becoming increasingly inconvenient.
Within Deliverable 1.3 (D1.3) the targeted requirements for the heat recovery system were presented. A summary of these identified objectives is provided within Table 1.
Table 1. Heat Recovery System Objectives
Objective Comments
Provide a high level of thermal efficiency.
Increase the level of thermal efficiency above 70%.
To be available at reasonable cost. I.e. provide a payback period of less than 10 years.
Consider production costs/manufacturing methods to ensure a cost viable solution.
To meet the required EN standards for stove operation.
Obtain feedback from expertise within the project consortium.
To maintain an aesthetically pleasing design.
Adhere to pre-set size requirements. Ensure presentation is in parallel with existing stoves on the market today.
A joint collaboration between AIC (SME) and Ikerlan (RTD) has led to the successful development of a Heat Recovery System adhering to the preset project objectives. A core component of this system, which has undergone extensive development work within the project, is the Heat Exchanger system. A key area of novelty that was presented within the initial Intelli-Flue design was the notion that a heat exchanger system could be applied to a domestic stove, utilising the excess heat that would be ordinarily lost to the flue.
The main design specifications for the Intelliflue HE were defined as the following:
• The HE must be cost effective (simple design).
• Maximum allowed dimensions: 400 mm height (max 600 mm, including top and bottom conical sections), 225 mm outside diameter, allowing for a 150 mm flue pipe connection on top and bottom).
• Should not weigh more than 20 kg.
• Minimum heat transfer from the fuel to the water: 2.5 kW, with 60 ºC water inlet temperature.
• No fumes condensation is permitted.
• The system should be aesthetically pleasing, and easy to perform cleaning maintenance.
• System efficiency range between 70% and 80%.
• The level of pressure drop throughout the HE unit should be below 10 Pa, as the minimum allowed draught in the chimney is 13 Pa (at nominal firepower). Moreover, the heat transferred to the water should be significantly higher than 2 kW to make it possible to rise the overall stove’s efficiency from 50% to 70%.
The provision of increased thermal efficiency is reliant upon the control of a range of variable parameters, which were considered in depth throughout the project. These are demonstrated within Table 2. Having successfully identified these, it was then necessary to incorporate their consideration within our future testing and analysis.
Table 2. Variable Parameters for Consideration
Parameter Dependent Factor Action
Level of Fume Flow Stove’s combustible load Define constant loading value
Fuel Description (I.e. seasoned or unseasoned) Select constant fuel
Fuel Shape Define regular branding/source of fuel throughout the project.
Fumes Inlet Temperature Test Stove’s Efficiency Level Use of single stove for testing.
Water Flow Rate Use of pump or natural draught Investigation of most appropriate solution during project.
Water Inlet Temperature Efficiency of the Heat Transfer System within the Home Transfer heat to a standard water tank during testing.
The expected temperature for the heat exchanger’s (HE) water inlet will be highly dependent upon the home’s heat transfer system. As a guide the following temperatures were identified:
- 25-30 ºC, for radiant floor
- 30-35 ºC, for fan-cooling (air) based heating
- 45-50 ºC, for low temperature radiators, and
- 60-65 ºC, for high temperature radiators.
This temperature must be taken in to consideration, due to the fact that the efficiency that can be provided by the HE is directly linked to this information. Should the temperature of the inlet differ significantly, the other factors become unknown. We would therefore be unable to predict the efficiency of the system to an accurate level. This is of even more importance in solid fuel stoves as supposed to alternative domestic heating appliances, for example, boilers or water heating tanks. This is due to the fact that in boilers, the average fume temperature is higher than 1000°C. However, it is thought that in the case of a stove, the expected temperature of the fumes entering the HE will normally remain less than 550°C. As a general rule, within a correctly functioning heat exchanger, the higher the inlet water temperature, the lower the HE efficiency measurement.
Having assessed these requirements, a number of alternative designs were produced for the desired HE. Table 3 presents a summary of 5 designs assessed as part of the development process. Comparisons were made between each individual design, with conclusions drawn based on their theoretical performance. Initial testing was conducted on a software basis (CAD); this was able to assist in identifying which designs should be taken forward to the production phase.
Table 3. Summary of Potential HE Designs
Version 1
Three rows of tubes with 25, 35 and 45 tubes (a total of 105 fumes tubes).
Tube geometry:
Tube length = 120 mm
Central fumes bypass tube.
Results from the CFD analysis:
Heat transferred = 3.27 kW
Pressure drop in fumes = 2.0 Pa
Mean outlet fumes temperature = 100°C.
Conclusion:
The HE is oversized. High risk of condensation
Water side design not analysed
Version 2
One single row of 36 tubes in a single circumference.
Tube geometry:
a=7 mm; b=5 mm; c=34 mm: d=41mm
Tube length = 120 mm
Central fumes bypass tube
Results from the CFD analysis:
Heat transferred = 1.96 kW
Pressure drop in fumes = 8.7 Pa
Mean outlet fumes temperature = 221 ºC
Conclusion:
HE is clearly undersized, and this tube tube’s geometry is not manufactured by AIC
Water side design not analyzed
Version 3
One single row with 23 tubes in a single circumference. Longer and thinner HE.
Tube geometry:
a=7 mm; b=5 mm; c=34 mm: d=41mm
Tube Length = 190 mm (120 mm modelled)
Central fumes bypass tube
Results from the CFD analysis:
Heat transferred = 1.46 kW (2,31kW for a 190mm long tube)
Pressure drop in fumes = 13.5 Pa
Mean outlet fumes temperature = 275 ºC
Conclusion:
Heat transfer nearly sufficient but fumes pressure drop too high.
Version 4
One single row with 32 tubes in a single circumference. Bigger cross-section tubes.
Tube geometry:
a=7 mm; b=5 mm; c=54 mm: d=64mm
Tube Length = 150 mm
No fumes bypass tube (tube blocked)
Results from the CFD analysis:
Heat transferred = 2.21 kW
Pressure drop in fumes = 1.8 Pa
Mean outlet fumes temperature = 183 ºC
Conclusion:
Valid design, from the “fumes side”. Version suggested to AIC for the final HE’s CAD design.
Water side design not analyzed
Version 5
One row with 36 tubes at two different radii defined in the HE.
Tube geometry:
a=7 mm; b=5 mm; c=54 mm: d=64mm
Tube length = 150 mm
No fumes bypass tube: acting as a water distributor
Results from the CFD analysis:
Heat transferred = = 2.95 kW
Pressure drop in fumes = 1.7 Pa
Mean outlet fumes temperature = 116 ºC
Conclusion:
Good parameters agreement. Heat transfer higher than specified (2,5 kW). HE’s final design, from AIC, for the 3D CFD modeling (water and fumes side).
The designs were then assessed according to their performance against a variety of parameters. Namely these observations were against Heat Transfer (kW), Temperature of Outlet fumes (°C) and risk of condensation. The results provided following this assessment can be found within Table 4.
Table 4. Analysis of Proposed Heat Exchanger Unit Designs
Both versions 4 and 5 were able to successfully demonstrate the required characteristics. Taking the above results into consideration, along with a number of detailed conversations between AIC and the remainder of the project consortium, the most appropriate design to be explored further was Version 5. This was due its superior level of heat transfer of 2.95kW in comparison to version 4’s 2.21kW.
Figure 1 shows the preliminary CAD design of the HE, based on the results of the CFD modeling. This is then followed by Figure 2, demonstrating the AIC produced version of the first phase HE.
Figure1. Computational Image of First Phase HE (Version 5)
Figure 2. Photographs following production of the first Heat Exchanger prototype.
As there are many parameters affecting the stove and HE’s efficiency, several tests have been designed within the project, in order to check the performance of the system. The system was tested rigorously, utilising a range of conditions to obtain a clear view of the overall performance.
Tests were defined as follows:
Preliminary Stove Testing (Phase 1) –Such tests were designed to measure the stove’s efficiency under different wood load conditions (reference tests). This test was also repeated with different damper positions to check the influence of this parameter against the wood burning rate.
Combined Stove and Heat Exchanger Testing (Phase 2) – These tests would measure the total system efficiency under similar conditions as in the previously tested during phase 1. The overall purpose was to identify the operating efficiency of the HE system. As with phase 1, such tests were replicated by alternating the position of the damper component. Changes in the rate of wood burning were then assessed.
The first phase of testing, conducted with a purposely built heat exchanger unit, was undertaken with differing results. It was decided that improvements could be made surrounding the level of condensing created by the fumes and carbonaceous emissions. These processes were having the unfortunate effect of producing undesired tar and fouling within the HE. The most pleasing elements of the phase 1 tests were related to the thermal efficiency achieved, which was able to reach up to 80% during certain experiments. The resulting recommendations were summarized as follows:
• The HE must be re-sized: The first sample was oversized, with the dimensions of the fume tubes above the required level. This led to unacceptable levels of fouling. The removal of dimples within the fume tubes was suggested. The decision was also taken to utilize fewer tubes. Should this option be taken, the width of the fume tube would be increased.
• The damper feasibility is not clear: Significant drops in the level of fume pressure, along with severe cooling of the fumes within the HE significantly hampers the stove’s draught and combustion rate. Closing the damper had little effect. It was recommended that the damper could be removed for the purposes of combustion control.
• Cold Ignition of the wood is highly labour intensive, and can result in fumes/gasses entering the room where the stove is based. Potential options to explore included reducing the water volume within the HE.
• The current HE’s cleaning procedure is time consuming and excessive. Fume tubes were judged to be too small in terms of width, and along with dimples, reduced access to the required areas.
• Incorporation of a Fumes bypass would reduce ignition problems and fouling activity. Inclusion of a fume bypass was therefore recommended.
These recommendations were considered by AIC, with the support of Ikerlan following which a second version of the heat exchanger unit was produced. The final heat exchanger design is summarised within Figure 3.
Figure 3. Photographs of Phase 2 Updated Heat Exchanger
The HE’s main differing features are as follows:
• 15 fumes tubes, with 62 *11 mm2 dimensions (59*8 mm2 cross-section), and 175 mm length. Hydraulic diameter: 91 mm
• Total HE height: 386 mm
• HE’s active part height (between flanges): 290 mm
• Total cross-section in the 15 tubes: 6.500 mm2 (5.300 mm2, in the former HE1)
• Total heat exchanging surface: 195.200 mm2 (194.700 mm2 in the former HE1)
• Total HE weight: 13 kg.
The dimples (indents) within the tubes, used during the production of the first phase HE, were removed for the second phase model, this decision was taken in order to reduce the tendency to fouling within the fume tubes.
The second phase heat exchanger demonstrates three sections, each one with 5 fume tubes (right), and three fumes by-pass sections (left). Each section occupies 60 º of the HE top circular cover.
Our design then seeks a damper system installed above the HE. This is integrated with 2 mm space and connected to a step motor. As a result, this will prevent fumes passing by blocking the passage through the HE tubes or fume bypass. Partial blockage is also possible if required. Figure 4 shows the described damper actuator, enabling full or partial blockage of the tubes when required.
Figure 4. Damper actuator with the described modifications.
Finally, a window for visual access to the damper, as well as the supporting frame for the stepper motor, were added to the new HE’s top cover (Figure 5.)
Figure 5. New HE’s top cover with a window for visual access to the damper position
1.2 TEXTILE LINER
A core feature of the Intelli-Flue technology is the textile which will make up the chimney flue lining structure. Intelli-Flue is not solely about reducing expenditure on a financial level, but also promoting safety for European homeowners. This will be achieved through limiting the thermal energy transferred to the chimney walls to a maximum of 150°C, thereby significantly reducing the risk of fire. A primary danger of existing metallic (steel) flue lining systems is the level of heat that is transferred towards the surrounding structures. In some cases temperatures can reach up to 350°C, generated by flue gasses that can establish temperatures of up to 600°C. Assuming that this is the case we can assume a heat transfer rate of between 58 and 60%.
In order to meet the Standard Assessment Procedures (SAP), solid fuel stove burners have improved their combustion efficiencies during past decade, by using secondary and tertiary burners, which has significantly increased the amount of heat produced, and hence, the temperatures that the chimney liner is exposed to. Consequently, excessive heat is being transferred to the brickwork and surrounding building structures. The problems cannot be negated by operating stoves at lower temperature (inefficient combustion) as this will increase residue/condensate build-up in the flue which will further increase the risk of chimney fire.
The project objectives were therefore defined to seek a solution which enables the following:
• To limit heat transfer from the flue gases to brickwork or surrounding structure
• Thermal and mechanical sustainability for the temperature cycling of 5 °C to 750°C
• Liner flexibility (bend radii of 60 °C) to reduce installation time by 50 %
• Around 50 years of corrosion performance of flue-liner
Furthermore, the liner should:
The general system specifications will bring the following:
• Flue diameter: 155 mm inner diameter i.e. ¾ of store cross-section and a maximum outer diameter of 185 mm.
• Chimney is considered to have a square cross-section with sides of 225 mm and reduces to 200 mm at bends.
• Flue length of 10m is considered as the necessary length for the Domolab (test house) building. Bends with 40 º maximum. For a typical two story house flue length of 10 m and a maximum bend angle of 45 º.
• Pressure drop in the chimney: Natural draught not lower than 3 Pa under any conditions (according to the EN-13240). This is the pressure difference that needs to be retained to achieve no draught when stove is not lit.
• Typical life-time for existing ceramic flue liners is 25-30 years
• Operating liner temperature: 600 °C
• Outside liner temperature: 150 °C
• Flue’s thermal Insulation: Commercial double tube chimney with thermal insulation in between the tubes.
• Specflue’s ceramic liner has a ceramic layer thickness of 4 mm and can be used as a starting value.
The proposed flue liner is composed of four layers. As shown in figure 1, the innermost layer is made of a ceramic material and a three dimensional textile.
Figure 6. Cross-Sections of the Proposed Flue Liner Design
Primary Testing Procedure
The temperature cycle specifications for the liner testing are the following:
• Test 30 min @ 1100 °C: protect building in case of chimney fire, mechanical stability, Liner is replaced afterwards
• Test 4 h @ 750 °C is for max. operating temperature of 600 °C (Test name T600)
• Test 4 h @ 600 °C is for max. operating temperature of 450 °C (Test name T450)
Initial testing included a computational fluid-thermodynamics analysis which was carried out to assess the performance of the proposed flue liner design.
In order to understand how thermal characteristics of flue liner material affect the temperature distribution in the chimney, two types of analyses were carried out. The boundary conditions for the first analysis was defined by the industry standard conditions for testing to assess the capability of the flue liner to maintain integrity over a period of four hours while the flue gases are at 750oC.(Figure 5)
The second scenario was defined based on operational conditions where the exhaust gases were maintained at 100oC to represent the temperature at the outlet of the heat exchanger when it is operational.
When the exhaust gases were maintained at 750oC over a 4 hour period the temperature in the brick wall remained just below 150oC - thus complying with the safety requirement.
In the computational model an air gap was implemented between the outer wall of the flue liner and the brick wall. This results in a considerable reduction in the temperature of the wall. However, in practice, maintaining an air gap is not always possible unless the liner is specifically designed to maintain the air gap. It is therefore expected that the temperature distribution will be higher than predicted in figure 5.
When the backing insulation material was changed the resultant temperature distribution was similar for ceramic fibre and Rockwool and the highest chimney wall temperature with each material only showed a difference of about 1.6oC. With Microporous as the insulation material, it reduced the chimney wall temperature by about a further 10oC compared with the other two materials.
The temperature distribution through the brick wall under normal operational conditions with heat exchanger turned on and after a period of four hours is depicted in figure 6. The computational results show that the temperature of the brick wall remains below 30oC. Reduction in temperature across the flue liner is higher with when the backing insulation is Microporous when compared to Ceramic Fibre and Rock Wool.
Figure 7 – Temperature Distribution Along the Center-line in the Chimney after 4hrs Exhaust Temperature at 750oC
Figure 8 – Temperature Distribution Along the Centre-line in the Chimney after 4hrs Exhaust Temperature at 100oC
Computational fluid-thermodynamic calculations were carried out on a proposed flue liner design in order to analyse the performance characteristics with respect to geometry, materials and layer composition. The initial computational model composed of a thin section of a flue liner and chimney walls with an air gap between the two. It was found that this air gap to play a significant role in reducing the heat transfer from the flue gases in to the wall. The reflective layer however was found to be of low significance with regards to its effectiveness as a thermal barrier.
The computational tests carried out to investigate the thermal performance by varying the tri-layer combination thicknesses showed that a 1mm reduction of the air gap between the textile layer outer surface and the outer surface of the ceramic layer to cause a temperature drop of about 16oC across the flue liner. Whereas increasing the air component within the textile layer which is considered as a composition of air and e-glass showed an improvement of only about 0.3oC – 0.4oC in the chimney wall.
One of the baseline criteria for assessing thermal performance was the ability of the flue liner to maintain the chimney wall temperature below 150oC over a period of four hours while the flue gases are at 750oC representing the industry standard flue liner test conditions. The tests carried out showed that the proposed design is capable of satisfying this requirement. When the flue gasses were maintained at a standard operating temperature of 600oC, with all the tri-layer combinations the highest temperature in the chimney wall remained below 100oC.
1.3 CERAMIC FORMULATION
The Intelli-Flue project has pursued the objective to increase the consortium’s level of understanding surrounding the rheological and mechanical behaviors of ceramic materials. This was done with the view that this research could be applied in order to develop a suitable inner lining material which would be applied to the textile liner. It was important that the behavioral characteristics that could be attained would meet the necessary parameters in order to satisfy performance expectations within a domestic chimney environment. The preset criteria for the ceramic formulation were defined as follows:
• To maintain performance within a temperature cycling environment (5°C to 750°C).
• To develop a satisfactory level of impregnation between the ceramic material and the inner surface liner.
• Deliver 50 year anti-corrosion performance.
The project set out originally in order to develop a flexible ceramic material which would be applied to the textile liner prior to application. However, the first period of the project saw the undertaking of a number of analysis and testing exercises which determined that this may not be possible. The principle reasoning behind this was that the storage and hence workability of the ceramic (limited to 14 days) and the transportation complications that would be incurred through such an approach. The decision was therefore made that an in situ application method would be explored.
It was therefore necessary that research was directed towards a ceramic formulation which could provide the correct workability which could be applied following installation of the textile liner. Different methods of ceramic application process would be assessed for their viability. The three methods identified within this project are manual pasting, pouring and spraying.
2. MATERIALS, COMPONENTS AND STRUCTURE
2.1 HEAT RECOVERY SYSTEM
The Intelli-Flue heat recovery system is comprised of 3 ‘sub systems’ which when combined are able to provide a complete solution. The 3 elements to be considered are the heat recovery, closed circuit and control systems. Figure 9 clearly shows how these are combined within the prototype set up.
Figure 9. Demonstration of the Sub System Lay Out
The Heat Recovery System is the main sub system in its own right. The heat from the fumes is then transferred directly to the water circuit. The system specifications are detailed as follows:
1. The heat exchanger, with the fumes damper, the stepper-motor support frame and the windows in its top cover providing access for mechanical cleaning
2. The stepper-motor: 42 mm, 44 N*cm 0.9 deg. 2.8 V, from RS
3. The mechanical damper rotation system
4. The connector of the stepper-motor with the mechanical damper rotation system, allowing for some misalignments of the motor axis and rotation system axis: Double Loop Couplings with Steel Hubs
5. Double Loop Couplings with Steel Hubs
6. The outlet fumes temperature sensor, placed downstream the fumes damper and in a “radial” location: presently a K type TC, but could be substituted by a NTC with the range 0-300 ºC.
7. The inlet water temperature sensor, placed in the top water connector: presently a T type TC, but could be substituted by a NTC with the range 0..120 ºC
8. The outlet fumes overheating thermal switch (On-Off), located downstream the fumes damper and in a “radial” location
The water overheating switch (On-Off), located in the top water connector.
The next sub system to be considered is the Closed Circuit system. This component is responsible for the integration of the Intelli-Flue technology towards a domestic heating system. The general purpose is to make the transfer of heat energy into the house possible, whilst eliminating the risk of cold water entering the heat exchanger during the stove ignition process. This would have significant negative impact through the production of condensation and tar occurring within the fumes tubes. The proposed system will include:
1. Metallic supporting panel, to make the closed circuit system installation easier.
2. Circulation water pump: UPS 15-30 130
3. Circular Expansion Vessel
4. Hydraulic connection circuit-expansion vessel
5. Safety Valve
6. Air Purge
7. Water Pressure Gauge
8. Circuit Draining Tap
9. Thermostatic Three-Way Valve, with 60 ºC set-point.
10. Flexible high temperature hoses connecting the HE with the closed circuit system.
11. High temperature flexible tube for the potential water vapour discharge from the safety valve to the drainage system.
12. Raccords and copper tubes.
Finally, the control and automation system will provide sufficient monitoring opportunity for the end user of the Intelli-Flue system. This will consist of a multi-functional display unit, enabling full control within an aesthetically pleasing manner. Typical inclusions within the planned system will also include, but may not be limited to the following:
1. A multi-function display
2. A reset button for resetting the accumulated stove’s working hours.
3. A yellow pilot: for an “alarm situation” indication
4. A buzzer, for “severe alarm situation” indication
5. A battery based, independent safety system for activating the buzzer in case of an alarm situation (even under mains blackout). Connected to the thermal switches.
6. Cables for connecting the sensors and actuators in the previous subsystems
Table 5 outlines the performance of the Intelli-Flue Heat Recovery system against those plans originally set out within the end user requirements. As can be seen on the table, all the values obtained with the system developed are significantly better than the values initially specified for the process variables.
Only the diameter finally defined is longer than initially specified, but this is largely compensated by the reduction on the other HE dimensions, and the significantly lower HE weight.
Table 5. Comparison of Performance against Initial Targets for the Heat Recovery System.
VARIABLE SPECIFIED VALUE REAL VALUE IN TESTS
Maximum allowed HE height 600 mm 386 mm
Maximum allowed HE diameter 225 mm 300 mm
Maximum allowable HE weight 20 kg 15 kg
“HE+ stove” efficiency range 70-80 % 79 ºC
HE’s minimum thermal efficiency (with 50% eff. stove) 25 % 35 %
Minimum average fumes-water heat transfer rate 2.5 kW 3.5 kW
Maximum operating fumes temperature in the chimney 300 ºC 200 ºC
Natural draught, in the chimney > 3 Pa > 10 Pa
Pollutant emissions, CO, in fumes (at 13% O2) < 1.0 % < 0.8 %
2.2 TEXTILE LINER
The performance of the chosen textile will have a direct impact upon the overall performance of the Intelli-Flue liner. Each layer is required to contribute the desired characteristics such as temperature performance, flexibility, memory shape and structural credibility. An array of potential textile materials was considered throughout the design phase. Table 6 highlights those potential options considered, along with their performance characteristics.
Table 6. Analysis of Possible Fibre Materials
Having successfully conducted this analysis, the potential combinations of materials were discussed. As originally highlighted within Deliverable 1.1 these were defined as follows:
• AR-glass fibre with PTFE fibre, this can be the best combination because both of them have good corrosion resistant properties, good working temperature and also by combining both of them low tenacity of the PTFE fibre can be compensated.
• S 2 glass fibre definitely has better properties than AR-glass fibre but it is expensive. S 2 glass fibre can be combined with p-Aramid fibre; this combination is also good combination by exhibiting the properties very near to the requirements.
• PBI fibre with PBO fibre, both fibre material exhibits good corrosion resistant, fire resistant and good working range. The tenacity of PBI material will be compensated by PBO material.
• PI fibre with Polyester fibre, this combination has good working temperature range, corrosion resistance but their tenacity is not good. This combination is chosen because PI fibre is expensive and Polyester fibre is cheaper one so the price can be compensated.
The planned deviation from a pre impregnated liner, to in situ ceramic application means that the liner construction must be favourable towards spray application. The structure of the textile liner contains three single parts. The nonwoven on the inside of the liner allows a closed textile surface. That`s important for the in-situ application of the spraying system. The ceramic application needs this element as a base structure.
The second part is the 3D-spacer fabric which creates an air gap with a thickness of 10 mm. This provides a good functional insulation. A braiding or another nonwoven surface completes the structure on the outside. This textile element provides a fixation of the geometrical shape and protects the textile liner during the injection process into the chimney.
The final construction for the proposed Intelli-Flue liner is summarised as follows:
• Internal basalt 3D fabric with vertical stubs
• Double layer of Basalt non-woven material.
• 25 mm X 25 mm basalt geogrid with bitumen coating
• Glass Overbraiding
If required, the vertical flexibility of the liner can be adjusted through changing the dimensioning of the geogrid. This is likely to improve the performance of the liner in terms of reducing the risk of any potential ‘kinks’ forming during the installation process. This is especially necessary for installation in complex chimney stacks. It is suggested that when horizontal stiffening is closely spaced, this will provide greater flexibility in the liner. Hence, in the case of Intelli-Flue, it would be possible to change the existing style of geogrid from a square to a rectangle with closer horizontal stiffening as compared to the existing geogrid (i.e less than 25mm) and further vertical stiffening (i.e greater than 25mm).
2.3 CERAMIC FORMULATION
The resulting ceramic formulation is accompanied with an easy handling and processing technique which will maximise the efficiency at which this material can be applied. The material can be transported and stored in a ‘dry mix’ state, to which water can be added, along with the required accompanying liquid state components. This is then mixed with the use of a paddle mixer, or equivalent for a short period of time, before being applied by the chosen method.
Within the Intelli-Flue project, the consortium has been able to define that the most appropriate method of application will be spray. However, it is clear that there is still a proportion of further development work that will be required in order to fine tune this application process. The spray head to be used will need to be matched in terms of capability against consistency of the mixture, viscosity and flow rate. This will maximise the mechanical bond between the ceramic and the inner textile liner.
The chosen ceramic formulation selection was the result of an extensive analysis of over 30 samples. The Intelli-Flue project has clearly demonstrated the potential and capability in terms of performance for the ceramic formulation. The chosen sample has undergone extensive testing within a real life chimney environment, showing no signs of cracking, corrosion resistance or void development.
The project has also made significant attempts to produce an integrated solution, attempting to coat the textile liner with the chosen ceramic slurry. Three application methods have been explored within the project, manual pasting, pouring and spray application. Out of those tested, it would appear that spray application is likely to be the most viable application method within a commercial environment. However, the process for completing this is still under investigation within the consortium. The mechanical bond between the ceramic and the textile is judged to be of an appropriate standard. However, ensuring an even layer of ceramic across the entire length of the liner is proving challenging. This will be investigated further following completion of the project.
It should be stated, however, that the development of a suitable formulation has been successfully achieved, and it has been confirmed that spray application is possible with the consistency of the ceramic slurry developed. We therefore propose that with a small quantity of further development work, we can succeed in the development of an acceptable solution for introduction into the commercial market.
Potential Impact:
1. INTRODUCTION
Once introduced into the commercial arena, Intelli-Flue will have the potential to generate a substantial positive impact, both commercial and technical. The overall technology represents a number of sound technological advances, which when combined with the commercial potential, create an exciting opportunity for our consortium members, and a valuable solution for our target customers. In order to truly assess the socioeconomic impact created, it has been necessary to pay special attention to the quantitative and qualitative measurement of impact.
Table 2. demonstrates the sales forecast that has been created for the Intelli-Flue technology. This forecast is based solely on new system installations.
Table 2. Sales forecast for the Intelli-Flue Technology
Year Number of Intelli-Flue Systems Projected to be Sold (entire system) Size of Market (Number of Units Sold per Annum) Total Market Penetration (%) Revenue Achieved (€m) Planned Profit (€m)
2014 400 2,000,000 0.02 1.32 0.25
2015 2050 2,050,000 0.1 6.76 2.60
2016 6303 2,101,250 0.3 20.79 4.87
2017 8615 2,153,781 0.4 28.42 7.22
2018 11038 2,207,625 0.5 36.42 10.00
*Assumptions:
A market growth rate of 2.5% per annum.
Intelli-Flue selling price €3,300
We anticipate that the Intelli-Flue product has great potential to assist our consortium members in growing their own business. In addition, our network organisations (to be identified to aid installation throughout Europe) will also have the opportunity to pursue growth. The additional revenue to be attained by the consortium as a whole will lead to the creation of up to 75 new jobs. This assumes 1 new post generated per €100,000 profit generated. Furthermore, there will be an additional 30 new jobs created within our network partners/suppliers (Assuming a minimum of 2 people per member state, within the 15 largest markets for Intelli-Flue.) These forecasts are assuming a very conservative market penetration level, only 0.5% within the 5 years post project. It is therefore highly likely that these figures can be exceeded, and the commercial performance of the Intelli-Flue technology improved even further.
Figure 1. Sales Forecast for the Intelli-Flue Technology
Figure 2. Revenue Forecast for the Intelli-Flue Technology
The forecasts provided take into consideration that full commercialisation will take place in 2014, and then project the following 5 years’ sales. It has been assumed that total profit available from the sale of a single unit will increase with the economies of scale available through mass production. In summary, profit per unit will vary between 5% (2014) and 20% (2018). Sales and revenue forecasts are demonstrated graphically within Figure 1 and Figure 2 respectively.
3.3 Unique Selling Points to Provide Commercial Success
Both components of the Intelli-Flue technology (Liner and Heat Recovery system) have defined unique offerings that set them apart from competitive products.
3.3.1 Flexible Textile Liner System
• Reduced Insurance Premiums
The Intelli-Flue system provides potential to significantly reduce insurance premiums – Insurance companies have been taking measures to reduce the risk of paying out by using premiums or high insurance quotes for properties that have not used industry approved fitters/installer and are deemed to be at risk.
Specialist insurance firms for thatch houses currently provide a variety of incentives for customers using certain installers/technologies/equipment which can reduce the overall risk of fire caused by poor chimney maintenance. For example, NFU mutual will provide discounts on insurance premiums if Magma Fire Stop or Thatch Firewall has been installed during the past 5 years. Such schemes provide customers with an incentive to take up new technologies, designed to reduce the overall risk to the insurance provider. Some Insurance companies will no longer pay out for chimney fire damage unless the flue has been swept and maintained by a professional chimney sweep who can issue a valid certificate of sweeping recognised by the insurance companies themselves.
The Intelli-Flue consortium will seek to open discussions with underwriters in a bid to offer similar incentives through installation of the proposed system. This will not only increase the market potential for Intelli-Flue, but also assist towards reducing the overall number of claims made due to chimney fires. Affordability is also improved for the end customer.
• Ease of Installation
The ease of installation for the Intelli-Flue technology is significantly improved compared to that of competing pre-fabricated flue liners. We anticipate that the entire installation of the Intelli-Flue system will take place within 1 working day. This is comparable to existing single-wall, flexible steel flue liners, which are less than ideal solutions as previously stated within this report. Cost of installation will be lower (liner and installation will cost approximately €1600) thereby representing improved value to the final customer.
3.3.2 Heat Recovery System
• Improved Energy Efficiency
Generally speaking, the efficiency of domestic stoves is well below 50%, with most stoves reaching a maximum of 30% efficiency during general use. This is due to the high level of heat energy lost up through the flue. Our latest project results have suggested that we can improve this through implementation of the Intelli-Flue technology towards 85%. This will lead towards significant cost savings for the customer, reducing their overall energy bill. It is our intention to strive towards a total payback period, covering the cost of installation, of 5 years. This will be reliant upon the reduction of manufacturing cost through incorporating economies of scales as the demand for the Intelli-Flue product increases. However, as a consortium, we feel that this is achievable nonetheless.
Thatched Owners Group represents over 1 million homeowners throughout Europe. During a recent survey it was reported that only 2% of stove owners had their stove connected to a boiler system. Of those who did not, an overwhelming majority responded positively towards the Intelli-Flue product suggesting that it may be of interest, and something that they would be prepared to explore further. Payback period and overall bill reduction were considered as two things that were most important to potential customers. This feedback is extremely complementary towards our technology, and sets a sound target audience for the technology in the short term future.
Our consortium members represent leading organisations, working at the top of their industry. Their client base spans the majority of European member states, and their supply chains create an array of organisations, including multinationals, medium and micro enterprises. Combined, Intelli-Flue is demonstrating the combination of transnational commerce, encouraging interaction between small, medium and large enterprises.
Within this Final Report, our consortium has taken the opportunity assess the impact of our technology, taking into consideration the thoughts of our partners, their customers and the surrounding stakeholders.
As outlined within our original funding application, our project consortium has always maintained that there is a clear need for an efficient heat recovery system for operation within a domestic environment.
We propose that the monitoring of the socioeconomic impact should be a continuous activity, and that this can take place at regular intervals (every 6 months) following the completion of the project.
2. DEMONSRATING SOCIAL IMPACT
Intelli-Flue has the potential to deliver a series of wider benefits throughout the European Community. The following section will seek to analyse these and provide a summary of the potential impact.
2.1 Providing a Contribution towards Decreased Levels of Fuel Poverty
Levels of fuel poverty throughout Europe are increasing. Typical fuel poverty is demonstrated when the home is cold, thereby presenting an unhealthy environment for the habitants, or when fuel debts accumulate. This is a topic that is currently debated at a high level across Europe, stimulated by increasing fuel prices and falling levels of disposable income within European households. It is suggested that within the United Kingdom, approximately 10% of households have fallen in to the category of fuel poverty; a similar statistic is echoed in Spain, Germany, Netherlands and Sweden. Even high levels, in excess of 20% are found in Poland and Lithuania with the highest level of fuel poverty registered in Portugal where 1 in 3 homes are detailed as struggling to heat their homes.
In 2000, the UK introduced the Warm Homes and Energy Conservation Act. This represents a parliamentary passed target for the reduction of the level of fuel poverty. This strategy included improving the energy efficiency of homes, seeking to reduce overall fuel consumption and therefore reduce levels of vulnerability to fuel poverty. Results were initially positive, reducing the number of households in fuel poverty during a period when energy prices were stable. However, since 2004, this trend has reversed due to fuel price increases. This is evidence that there remains very little tangible support for those households attempting to tackle fuel poverty. However, in 2013, the UK remains the only country to present such a measure. European households are struggling to maintain a comfortable living environment, caused by a lack of heating and lighting within the home. A major concern is that this occurs in line with a period when Europe seems to be susceptible to some of the most extreme winter weather conditions witnessed for a number of decades.
There are a range of health impacts that can be witnessed by habitants living in cold homes. This is supported by the Marmot Team Review (2011) which states that there is a direct link between poor health and living in a cold home. Fuel poverty places extreme pressure upon the lives of a range of people. It is not only related to physical illness but also mental health. This is thought to be caused by the financial trauma that is implied upon households attempting to tackle the rising debt and other problems associated with fuel poverty.
2.2 Seeking to Achieve Increased Levels of Fuel Security in Europe
European media sources are continuously promoting the vulnerability of European citizens due to the instability of the energy markets. Prices are fluctuating on a regular basis, with the general trend indicating price rises.
A resulting scenario is that consumers are increasingly prepared to consider alternative sources of heating and/or lighting within their homes. One such solution which is proving increasingly popular is the use of solid fuel burning stoves. This is reducing the dependency from homeowners on the most common forms of heating such as gas central heating/oil. Dependency on such fuels, produced through utilisation of finite resources, has produced a detrimental effect upon our surrounding environment, following decades of excessive and increasing levels of use. It is true that there are still supplies of oil and natural gas in existence, but the rate at which their use is rising, far exceeds the rate at which new supplies are being identified. Should the level at which the European Community, and indeed the Global economy is utilising such finite resources continue to rise, statistics suggest that both oil and gas reserves could be extinct by 2068.
In summary, we can confirm that the level of fuel security throughout Europe is put at risk through the following occurances:
Exhaustion of Energy Source – Oil and gas reserves are a limited resource, and their levels are falling. In addition, 90% of world reserves are controlled by firms based within the Middle East and Eurasia.
Economic Risk – Energy products are subject to extreme fluctuations in price. Supply and demand can cause prices to rise suddenly in short spaces of time, which can significantly impact the energy market suppliers in Europe, with price rises being passed on to the end consumer.
Geopolitical Risk - Government decisions to suspend deliveries of oil and gas because of policy, war, and/or terrorism can put supplies under significant threat. This has become over more apparent during the past 2 years with a number of uprisings threatening the supply to certain parts of Europe.
By improving the safety of solid fuel combustion and enhancing the efficiency of solid fuel combustion through energy recovery, Intelli-Flue will encourage Europe to increased solid fuel usage helping Europe to meet renewable energy targets by offsetting current dependence on oil and gas.
It should be noted that the positive impact of the Intelli-Flue technology is not only restricted to the monetary benefits available to the consortium and the end user, but also safety. We propose that the installation of an Intelli-Flue unit can substantially decrease the level of risk presented to a home relating to chimney fires. The severance and likelihood of chimney fires is often not considered by many households to be high. However, recent figures are stating otherwise, with the level of chimney fires increasing heavily during the past decade. It is thought that approximately 200,000 domestic fires per annum are the result of a chimney defect. Taking this into consideration, each and every European household with an operating chimney should seek to have regular maintenance checks conducted by a qualified chimney engineer. A report provided by the European Federation of Chimney Sweeps suggests that a survey conducted in 2010 indicated over 1 million defects in already existing chimneys, with a further 117,000 faults in newly built ones. Such faults represented a substantial risk towards fire safety. Such levels are not acceptable.
The Thatched Owners Group, coordinator of the Intelli-Flue project, has an existing relationship with the UK Fire Service. They have conducted a range of ‘road shows’ which promote regular chimney maintenance, and its effect on reducing the risk of chimney fire.
2.3 Preservation of European Heritage and Culture
The market potential for the Intelli-Flue technology is further enhanced by the fact that applications reach out to not only domestic homes, but also commercial buildings and historical sites (manor houses, heritage sites, period homes etc.) The perceived need for such a solution is further enhanced by the fact that a number of high profile heritage properties have suffered from the effects of a chimney related fire during 1992 alone ; Christianborg Palace Church, Copenhagen, Windsor Castle, Berkshire, England and Redoutensal, Hofborg Palace, Vienna.
Listed, period homes and heritage sites are in particular danger given the use of thatch and timber as traditional building materials. Given the significant number of heritage buildings and historic towns across Europe the potential for loss from chimney related fires is significant. We propose that wherever possible, this risk should be reduced.
2.4 Pursuing Confidence in Alternative Technologies
Consumers often demonstrate a degree of reluctance before pursuing the uptake of a new technology, especially those which require significant investment, substantial structural work and are untested within the market. Intelli-Flue has therefore taken careful steps to overcome these barriers and present a solution which encourages take up by the final customer.
There is currently a large amount of research being conducted, as well as product development activities which is seeking the introduction of new technologies which support the reduction in energy expenditure within European households. However, it is fair to suggest that considerable effort will be required in order to bridge the gap between product development and introduction into the marketplace. We maintain the opinion that the Intelli-Flue technology represents a novel solution to a highly publicised market need within the European Community.
Manufacturers must seek to encourage consumers to invest in alternative technologies, as well as allowing for the installation within their home.
There is also an ancillary argument which calls for the support of European governments in introducing such technologies to the market. This can come in the form of subsidies or grants and/or incentive schemes which promote the demand for new products. This can also act as a valuable marketing tool in promoting the technology to a wider audience. Recent efforts have taken place in the form of ‘Energy Smart Meters’ and ‘Solar/Photovoltaic Panels.’ Uptake has been promoted through the use of preferential rates/pricing strategies; however, impact in overall consumption has been so far been limited.
Intelli-Flue represents something different; no longer does the focus have to remain upon cost and ‘green’ credentials. We have now created a third dimension which could be considered to be the most important of all, that is increased safety to the end user. As the level of sales for solid fuel stoves continues to rise, the importance of safety and chimney maintenance will be of paramount importance. Intelli-Flue can have a leading role to play in the mission to improve the level of chimney condition and safety over the coming 5 years. Through being affordable, easy to install, and able to be retrofit to existing chimneys, our solution overcomes many of the barriers presented by existing attempts to lure customers towards alternative green technologies.
3. DEMONSTRATING ECONOMIC IMPACT
3.1 Progress through Collaboration
The Intelli-Flue technology is the result of a successful collaboration between a consortium of commercial partners on a pan European level. The transnational approach to this project has enabled varied points of view to be taken into consideration, incorporating a variety of cultures and legislative patterns represented by those countries involved within the project. It could also be suggested that this has allowed for a more thorough assessment of the market need.
It should be well publicised that the results so far created by the Intelli-Flue project are the result of a productive collaboration. Furthermore, there have been a range of indirect benefits that have been made available to the project consortium. The networking opportunities presented within the project have led to a number of commercial transactions for those involved, some within the consortium and some further afield within the European business community. The knowledge generated within the project has also enabled the further development of existing products within a number of consortium member’s product portfolio. This will lead to a unique offering which can provide a competitive advantage, benefiting the project consortium member even further.
If replicated, we propose that this could have a positive impact on the wider EU business community. There have been many studies conducted in relation to the impact that collaboration can have towards creativity and innovation. The bringing together of different levels of expertise, the inclusion of personnel from different hierarchy levels as well as representation from a range of industries, has enabled the project consortium to engage in a number of productive and thought provoking conversations throughout the project. The result from this is a large proportion of valuable knowledge exchange between partners, allowing for application not only within the Intelli-Flue technology but also within their individual businesses.
Such collaborations offer an array of networking opportunities, which enable those involved to maximise their benefit through being associated with the project. The success of the Intelli-Flue project has the potential to increase the appeal of European Commission financed partnerships which in turn could lead to an increased throughput of novel technologies for the future.
3.2 Direct Benefits for the Intelli-Flue Consortium
A clear commercial business case has been set up within the Intelli-Flue consortium, ensuring direct economic benefit to the consortium members. The impact of this benefit, however, will be realised on a wider scale, as suppliers, customers and the surrounding environment realise clear advantages within the short/midterm (up to 5 years post project).
Our data is calculated assuming that the current level of sales for domestic stoves totals 2 million units per annum. This figure is expected to increase steadily has consumers seek a cheaper alternative to gas/oil based central heating. For the purposes of illustration, based on our consortium knowledge of the market, we propose an annual growth rate of 2.5%. The Intelli-Flue consortium has therefore made a conservative target to achieving a market penetration rate of 0.1% within the first 24 months of production. This represents sales of 2450 units. It is important to note that this figure only relates to new stove installations. In addition, a target has been set to achieve a further 2000 sales through retrofit systems to existing chimney/stoves. It is thought that these targets are achievable based on the networks possessed by the project consortium, along with the extensive marketing and dissemination techniques to be conducted alongside the launch of the Intelli-Flue technology. These are detailed within the project’s Dissemination and Use Plan.
Assuming an average sale price of €3,300 for an entire system, this will represent total revenue in excess of €2million generated from the Intelli-Flue product within the first 24 months post project. The consortium has taken into consideration that revenue and profit levels will be affected by the fluctuation in price of raw materials/manufacturing costs.
The project consortium can also benefit through a number of additional ‘bolt’ on services that will be sold in partnership with the Intelli-Flue technology. For example, a comprehensive, after sales service package. It is already planned that these services will be offered by TOG in partnership with CICO for UK installations. Discussions with European network partners are also on going.
As take up of the technology proceeds, and identification of future Intelli-Flue branded products becomes available, it is thought that further commercial benefit can be realized. We therefore suggest that the commercial figures projected are somewhat conservative, and certainly achievable within the timescales provided.
List of Websites:
www.intelli-flue.eu