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Development of Thermal Storage Application for HVAC solutions based on Phase Change Materials

Final ReportSummary - HESTOR (Development of Thermal Storage Application for HVAC solutions based on Phase Change Materials)

The overall aim of the HESTOR project is to develop a novel HPCM-based thermal storage unit (TSU) system for enabling optimised performance and enhanced energy cost savings in HVAC systems. More specifically, the scientific and technological goals of the project are:

- to develop, design and construct the architecture for HPCM TSU, enabling improved storage performance and more effective heat exchange;
- to develop effective packaging solution for HPCMs by choosing type of materials, manufacturing technology and optimal surface size of packages / containers;
- to develop suitable control unit architecture with programmable user interface for the TSU system;
- to reduce power consumption of the HVAC system during peak demand and take advantage of less expensive nighttime energy leading to higher cost efficiency.

These objectives will be achieved through the following steps:

- Modelling the thermo-physical properties and phase change behaviour of HPCM
- Choosing the best options for given circumstances (need for heating or cooling)
- Researching the best-performing HPCMs containerisation materials enabling large surface area and strength, flexibility, temperature resistance, UV stability, thermal conductivity, compatibility and stability of the container
- Development of the architecture for thermal storage unit: the configuration of PCM containers
- Control unit design enabling the most effective recycling of warm or cool air in different out-door conditions.

While the validation of the fully functional prototype continues post project, initial results are the following:

- TES efficiency of 87 % in summer conditions and 77 % in winter conditions
- Power consumption during peak demand is reduced by 40 % in the prototype but could be reduced up to 80 % - 100 % with different configuration and size of the storage tank and with different set-point temperature use
- Reduction of CO2 emissions since when off-peak electricity is used, marginal power plants are avoided.

Project context and objectives:

In industrialised countries, 35 - 40 % of total primary energy is consumed by heating, ventilating and cooling of buildings. In Europe, 30 % of energy use is accounted for room and water heating alone1. From more than 480 M toe energy used in households and services annually, approximately 32 % is used in the service sector and 62 % is used in the residential sector. In service buildings, approximately 68 % of energy is utilised in room conditioning (heating and cooling) and the remaining fraction is used for lighting, hot water, etc. Therefore energy consumption due to ventilation corresponds to approximately 22 % of the energy delivered to the building and is generally seen as an area for significant savings. Complete adaptation of current building standards can achieve a reduction in electric energy consumption and therefore an increase in energy performance of buildings. Moreover, half of the projected increase in energy needed for air conditioning - expected to double by 2020 - could be saved through higher standards for equipment.

The EU has adopted three Framework Directives directly impacting the heating ventilating and air conditioning (HVAC) industry: the Energy Performance of Buildings Directive (EPBD), the Eco-design Directive for Energy Using Products (EuP) and the Energy Labelling Directive (ELD). The goal of EPBD and its impact on the HVAC sector as a whole is improving the energy efficiency of buildings.

Article 9 of the EPBD, according to which the 'member countries take the necessary action to ensure the regular inspection of air conditioning systems with a rated output of more than 12 kW in order to reduce energy consumption and limit carbon dioxide emissions', is especially relevant for cooling and air conditioning installations. This inspection involves an examination of the efficiency of the system and its dimensions in relation to the cooling requirements of buildings.

All three Directives establish a framework under which manufacturers of energy-consuming products will, at the design stage, be obliged to reduce the energy consumption and other negative environmental impacts occurring throughout the product life. The objective of all given Directives is to promote sustainable development and integration of environmental goals into both competitiveness and consumer issues (i.e. the Lisbon Strategy objectives). Experts from the EC's Directorate-General for Energy and Transport have revealed that 30 product groups have been selected for the regulations in respect of eco-design. The first regulations were adopted in February 2009. The regulations automatically apply to all member states and all products in the EU market must comply with these requirements. HVAC related product groups include boilers, water heaters, fans, pumps, air-conditioners etc are also covered by these regulations.

The most effective way to improve the performance of heat pump technology is coupling the pump with efficient and low-cost thermal energy storage (TES) system. However, the integration of existing TES solutions with HVAC systems is not a cost-effective solution compared to HVAC systems using primary energy due to large investments in initial capital costs for the end user and therefore market expects more suitable solutions with return of investments less than five years. The use of primary energy from the other hand has to be reduced in order to cut CO2 emission. Existing thermal storage solutions using solids or liquids require several times more mass and volume than phase change materials (PCM). The purpose of HESTOR project is the development of thermal storage unit (TSU) for HVAC solutions with optimised performance permitting enhanced energy cost savings in the use in business, public and industrial premises.

In the HESTOR project dynamic hybrid PCM (HPCM) will be used as a TES medium enabling the achievement of at least a 1.5 times higher energy storage capacity compared to existing solutions.

The system will consist of an insulated tank that contains macro-capsule packaged PCM in it. PCM packages will be thin carbon-reinforced plastic or metal alloy containers with high surface area in order to overcome the poor thermal conductivity of the PCM. The change in volume of the PCM has to be taken into account when designing PCM packages. In our system, warm air (or some other heat transfer medium) melts the phase change material hence cooling the air flowing through the material. If the temperature of the environment decreases, cold air initialises the crystallisation in the PCM and the released latent heat warms the air flowing through the PCM container. Our planned Control Unit system will enable the maintenance of the inner environment of TSU at a desired temperature.

By using organic PCMs such as salt hydrates or paraffins in combination with thickening agents / highly water absorbing materials it should be possible to overcome the long term stability issues of PCM. Major research aims of the project will be to develop a HPCM packaging solution with suitable thermo-physical properties and large surface area, researching the suitable packaging material, and development of the packaging architecture.

In brief, the scientific and technological goals of the HESTOR project are:

- to develop, design and construct the architecture for HPCM TSU, enabling improved storage performance and more effective heat exchange;
- to develop effective packaging solution for HPCMs by choosing type of materials, manufacturing technology and optimal surface size of packages / containers;
- to develop suitable control unit architecture with programmable user interface for the TSU system;
- to reduce power consumption of the HVAC during peak demand and take advantage of less expensive night time energy leading to higher cost efficiency.

Project results:

The main final results generated during the HESTOR project are as follows:

- HESTOR macroencapsulation technique and capsule design (PCM capsulation and configuration);
- HESTOR Thermal Storage Unit design and architecture;
- HESTOR Control Unit design, software and components solution;
- Integrated HESTOR system.

A brief description of findings under each project result are given below.

HESTOR macroencapsulation technique and capsule design

The main work towards this result consisted of the:

- modelling of the thermo-physical properties and phase change behaviour of HPCM in different determined circumstances; determining the properties and functions of PCMs used in TSU;
- researching the materials and macro encapsulation opportunities to be used in development of macro-containers;
- development of PCM capsulation technique for HESTOR TSU.

Some significant conclusions that were drawn from the research are listed as follows:

- The main advantage of latent heat storage is the high storage density in small temperature intervals.
- Variety of metal and plastic encapsulations are available in the market.
- Encapsulation can add mechanical stability to the system.
- Plastic containers have good compatibility with salt hydrate.
- Low thermal conductivity of the plastic encapsulation can reduce the heat transfer.

HESTOR Thermal Storage Unit design and architecture

In TSU development some essential requirements needed to be taken into account:

a) the PCM is charged at night and discharged during the day taking advantage of the low tariff overnight electricity;
b) salt hydrate PCM;
c) Nordic and Mediterranean climate conditions.

The TES unit was designed and configured to fit the purpose of the prototype, i.e. proof of concept and validation. The design of the unit will therefore need to be further adapted to requirements of real life capacities.

III HESTOR control unit design, software and components solution

The control unit was designed in a way to meet the functional and scientific measurement requirements in order to ensure high quality results from the validation process.

The main data to be measured were as follows:

- PCM tanks:
i. Inlet heat transfer fluid temperature
ii. PCM temperature
iii. Outlet heat transfer fluid temperature
iv. Heat transfer fluid temperatures inside the tank
v. Mass flow rate for each tank.

- Air handling unit (AHU):
i. Supply air temperature
ii. Outside air temperature
iii. Extract air temperature
iv. Return air temperature
v. Air temperatures before coils
vi. Air flow rate.

- Room:
i. Inside temperature.

The automation of the system was carried out with Carel pCO3 which is a microprocessor-based electronic controller widely used in the HVAC industry.

Work cycle optimality was also taken into consideration during the design and automation of the control unit. In the set-up of the controller, one should ideally avoid a situation where 100 % of the storage capacity is achieved in the midst of the period of inexpensive electricity since as a result, the compressor will switch off. As heat losses always occur, this may lead to the necessity of switching on the compressor again while its operating mode may no longer remain completely within the period of inexpensive electricity. Therefore, the controller should be set up in a way that the maximum storage capacity is achieved as much towards the end of the period of inexpensive electricity as possible. Such a set-up is not relevant for the prototype but will be important for the final product where real life capacities are reached.

IV Integrated HESTOR system

The validation of the fully functional HESTOR prototype in summer and winter conditions gave the following initial results:

- Power consumption during peak demand is reduced 40 % in the prototype but could be reduced up to 80 % - 100 % with different configuration and size of the storage tank and with different set-point temperature use.
- TES efficiency was measured at 87 % in summer conditions and 77 % in winter conditions but these can be further improved with better insulation.
- Pay-back time for commercial product was calculated to be around 4.5 years in case of use of salt hydrates as PCM and 13.6 years in case of use of paraffin as PCM.
- Reduction of CO2 emissions as when off-peak electricity is used, marginal power plants are avoided.

However, further validation is in progress and these results will be published in February - March 2013.

Potential impact:

Objectives

The main objectives of the HESTOR dissemination strategy is:

(a) raising awareness of the project, the consortium and project results; and
(b) supporting exploitation strategy and post project activities.

The ultimate goal of all dissemination activities is the use of foreground be it the final production of the HESTOR solution or application of results in other fields to create innovative solutions and generate business growth.

Target audience

The target audience of dissemination are the potential customers for the innovative solution, i.e. first and foremost the European HVAC industry and heat pump installation companies. TEINSA is leading the dissemination and exploitation activities in Southern Europe and TRV Kliima in Northern Europe. The primary markets that the SMEs will initially focus on are Spain and Estonia due to established client base of both TRV Kliima and TEINSA. Therefore, majority of project results' dissemination activities will take place in those countries to support exploitation efforts including establishing a business case to secure further funding necessary in order to take the HESTOR solution to market. After further post project validation, a more wide scale dissemination will take place, in particular in Scandinavia, Southern Europe and the UK.

Spain

TEINSA has identified the customers that could potentially be interested in the HESTOR solution. These companies are all already aware of the project and its objectives and TEINSA has made a commitment to disseminate, promote and offer the project results in these companies as soon as final validation results have been published.

As TEINSA has also published project information on its website (see http://www.teinsa.net online), there are many other companies which will indirectly learn about the project and its results as well.

Estonia

TRV Kliima has identified customers in Estonia that have displayed interest in the project and its results. The main clients would be facilities' administrators and maintainers and they can be best reached in two ways: via designers and real estate maintainers.

They can be reached via existing customer base or their association AEFAM (see http://www.ekhhl.ee/?id=551 online).

TRV Kliima has made a commitment to disseminate and promote the project results in these companies as soon as final validation results have been published.

All these companies, both in Spain and Estonia, will be addressed when sharing publishable material relating to the validation results. Furthermore, feedback will be asked from them in order to gain information on market potential and areas of improvement to turn the prototype into a successful marketable solution.

Content of dissemination

The content of dissemination is agreed upon by the consortium partners and needs to be approved by the exploitation board. This applies to dissemination activities during the project and post project. The terms of this process are regulated in more detail in the consortium agreement.

The main results subject to dissemination include:

- PCM capsulation and configuration
- TSUt architecture
- control unit design
- integrated HESTOR system.

In addition, raising awareness and promotion of PCM as an effective means for energy efficiency will be incorporated in the dissemination activities.

Sensitive information subject to potential IPR protection will not be disseminated until decision with regard to level of sensitivity and means of protection have been made by the exploitation board.

Medium of dissemination

Digital media is the focal point of the dissemination efforts. Vehicles of communication include the project website, company websites, association newsletters and in the future also social media to share project related information, news and events. Publishable materials include articles, posters (electronic and on paper), presentations and audio-visual media.

In addition to digital media, partners will participate in relevant conferences and seminars and use existing business relations to disseminate results and raise awareness of the project.

Implementation

Project website (see http://www.hestor.eu online) has been used as a means to share project materials and events where partners have participated in. It will remain updated post project to maintain web presence of the project and to continue dissemination and obtain feedback from target audience. Once final results are obtained and confirmed, a press release will be prepared and diffused in digital media, including the project website.

Exploitation manager will lead the post project dissemination activities from the SMEs' side. To reach potential customers in Estonia, TRV Kliima will attend local conferences such as Estbuild 2013 (see http://www.fair.ee/eestiehitab/ online). International conferences to be taken into consideration include Chillventa 2013.

In addition to carrying out dissemination activities in support of exploitation efforts, raising general awareness of the project and the importance of its objectives in current economic environment and increasing energy costs is also very important. The consortium will make a special effort in diffusing knowledge generated in this project in the format suitable for general public (such as videos introducing project concept and results) in order to display how EC funds have been used and what societal benefits could arise from such research and development. Therefore, RTD partners will support this goal by also participating in dissemination activities especially through universities to reach young people. UdL will carry out its activities through its own university and EII will help disseminate knowledge from Estonia's side where energy efficiency is an important discussion point at the moment.

Publishable materials

All publishable materials created by consortium partners will need to receive approval from Exploitation Board prior to disclosure. These materials will also include the following sentence to acknowledge the funding from the FP7 programme: 'The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7 2007-2013) under grant agreement No. 262285'.

The main publishable materials created during the project are:

- HESTOR poster I (results 1-2)
- HESTOR poster II (results 3-4 and validation results; will be finalised in February 2013)
- scientific articles
- flyers, presentations.

More publication of scientific and technical articles are planned on various project results (some are listed above), all of which will be either shared or provided a link for on the project website.

Exploitation of results

At current stage of the project where initial validation of the prototype has been completed, building a strong business case is the next necessary step. While results of the validation have been positive, especially in the area of energy efficiency, further improvements need to be made considering some challenges that the prototype validation process revealed. FMEA analysis also helped point out further possible weaknesses of the prototype which will be addressed in the refinement of the prototype design. In brief, building a strong business case will require three steps:

a) additional validation of the prototype with data gathered over a longer period of time and various conditions to achieve higher confidence levels and credibility of data;
b) cost / benefit analysis considering the final validation results;
c) further refinement of the system design taking into account experience and knowledge gathered in validation process, FMEA analysis and real life power / capacity levels and requirements.

After the business case has been built, further demonstration activities are necessary to show the HESTOR system functioning in real life conditions at real power and capacity levels. This would be necessary validation in order to fully convince customers of the benefits the system can bring.

Building a business case with the abovementioned three steps will be undertaken as follows:

- Refinement of the system design
Following the validation results and FMEA analysis, further refinement of the system design will be carried out by the SMEs using their own resources and know-how obtained in this project. Such refinement is necessary as current prototype was designed for proof of concept. Final design will need to be slightly modified so that it would be suitable for application in real life conditions. The main focus of refinement will be the reconfiguration of the containers, including possible modifications of the dimensions, size, shape.
- Additional validation
It has been agreed upon that UdL will carry out further validation after the project and will share the results with the SMEs. This validation will take place in Lleida, Spain. Validation will be done in co-operation with the Exploitation Manager, TRV Kliima. Validation will be carried out with partners' own resources.
- Cost-benefit analysis
Once additional validation results are obtained, a detailed cost-benefit analysis will be performed in order to complete the business case for HESTOR. Cost-benefit analysis will be ordered in Estonia from a qualified and neutral third party by the exploitation manager. For cost-benefit analysis, available funding from Enterprise Estonia (funding scheme: Innovatsooni osak) will be used.

Further demonstration activities and the concrete funding options to be explored will be more clearly defined in the next four months. However, with the exploitation manager from Estonia, funding schemes from this country will be explored first and foremost. With other SMEs from the UK and Spain, funding opportunities from these countries can also be analysed.

EU also offers interesting funding schemes that will be taken into consideration. The Eureka Eurostars Programme could be a suitable means to proceed after business case has been completed. The next application submission deadline is 4 April 2013.

Responsibilities

The post project exploitation and commercialisation efforts, including carrying out the funding strategy will be led by the exploitation manager and will include all SMEs. Further validation will be performed by UdL. Exploitation manager will also lead the refinement of the system design, based on know-how obtained in the project and feedback received from potential customers. Exploitation manager will also be responsible for preparation of applications for funding for demonstration and other activities to take the HESTOR solution to market.

Location

Further validation will take place in Lleida, Spain. Cost-benefit analysis will be ordered using funding from Estonia. Refinement of the HESTOR system design will be carried out in Estonia. Funding for demonstration activities will be applied first and foremost in Estonia but also at European level. In terms of commercialisation efforts, the primary target markets are Spain and Estonia.

Methods and resources

As mentioned above, the main resources used to carry out the activities related to fundraising as well as building the business case for HESTOR are a mix of partners' own resources (people and funds) as well as funding schemes available on a national and European level. Principal funding schemes considered for demonstration and exploitation activities are ones offered by national programmes as well as the Eureka Eurostars programme.

Socio-economic impact

The overall socio-economic impact of HESTOR system reaching the market is significant and this not only in terms of reducing energy consumption during peak demand but also providing real cost savings to the end-user. Already in the first demo prototype, power consumption during peak demand is reduced 40 %. However, this could be reduced up to 80 % - 100 % with different configuration and size of the storage tank and with different set-point temperature use. With rising energy prices and PCM market forecast to become more competitive in the upcoming years (i.e. PCM should become less expensive), the HESTOR solution will become truly attractive as the pay-back time will significantly decrease. With current prices, the HESTOR solution is projected to have a pay-back time of 4,5 years or 13,6 years, depending on the type of PCM used. Further development of the system as foreseen can decrease this pay-back time even more.

Increasing energy prices are a major concern for many, especially in the context of uncertain economic environment. Therefore, HESTOR system could have a major impact for small businesses, individuals and others who are most vulnerable to this.

Project website:
http://www.hestor.eu

Project co-ordinator:
Mr Roland Jung
Roland.Jung@trv.ee