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Innovative high efficiency phase change fluid based heat engine

Innovative high efficiency phase change fluid based heat engine

Final Report Summary - UP-THERM (Innovative high efficiency phase change fluid based heat engine)

Executive Summary:
Recent studies on the total CHP market report that:
- Growing demand for onsite power generation makes CHP the most suitable distributed power generation technology for industries and commercial enterprises. This because CHP not only generates onsite power but also satisfies heating and cooling requirements at reasonable costs;
- Increasing prices of fuel, such as natural gas and coal, has made customers shift towards new power generation technologies such as CHP, that increases efficiency while minimizing costs;
- It is estimated that with recurrent increase in the cost of electricity, micro-CHP can ideally help consumers save about 60% of their electricity bills;
- Large customer groups in the industrial and commercial segment are moving towards greater use of CHP technology, which would pave the way for significant market growth globally by 2017.
The overall market situation saw Germany and Italy leaders of the combined heat and power (CHP) market in Europe in 2013; Japan and South Korea were market leaders in the Asia-Pacific (APAC) region; and the United States led CHP market in North America. These countries are expected to continue their dominance during the forecast period. In terms of application:
i) industrial segment was the largest revenue contributor in the market with 55.2%, followed by
ii) institutional segment with 17.3%,
iii) the residential segment with 15.7%, and
iv) the commercial segment with 11.9%
Specifically, facilitation for the take-up of the results in the field of CHP generation is expected by:
1 – Government incentives, subsidies, emissions legislation and loan programmes implemented in North America, Europe and Asia actually promote the installation of CHP equipment. Legislation, in particular the one related to CHP and energy efficiency, prove positive steps towards this direction.
2 – Increased electricity prices have lead to the growing demand for technologies potentially improving the efficiency of fuel conversion, this because of the rapid and significant increase in prices that resulted in high generation costs and electricity bills.
3 – Environmental concerns has led regulators of major countries to implement strict policies to reduce harmful effects on the atmosphere, and a high number of regulatory measures, such as carbon credits and renewable portfolio standards, are meant to protect the environment in the long term. Such measures are expected to guide the growth of the global CHP market and have a moderate effect through the forecast period (2013 -2017).
4 – Increasing popularity of CHP systems lays in the fact that distributed energy generation can meet the growing demand for generation capacity, responding to the possible shortage of power predicted for the next future (losses, phasing out of nuclear power, etc.).
On the other side, barriers to the take-up of CHP generation lay in the following aspects:
1, 2 – Volatility of prices for natural gas has led end users to withhold investments into CHP equipment until more favourable political-economic scenario is in place. Additionally, the rising cost of gas and the resulting poor spark spread has not only cancelled prospective projects, but has also caused a number of existing projects to shut down. Recession fears and the shortage of capital threaten new project initiations, inducing weaker demand for CHP systems especially from smaller companies.
3 – Procurement of electricity at cheaper rates in one of the key challenges impacting the market penetration of CHP systems. This is highly prevalent in countries that have a well-developed power infrastructure.
4 – Finally, there is a social challenge raising from the lack of knowledge about the benefits of implementing a CHP system. Potential customers have to be educated about the savings in energy costs and improvements in energy efficiency through training, active media campaigning and other initiatives.
According to this analysis, the mentioned opportunities and threats can be also referred to the introduction of the Up-THERM technology in the CHP market for residential applications. Basing on these needs, the project coordinator TEP Energy Solution started a technological survey on innovative solutions, running into the heat engine configuration developed by University of Twente and described in the following paragraphs.
After the involvement of ENCONTECH B.V partner of UT in the heat engine idea development, NOON ENERGY and EFICEN, all the partners agree that this configuration could be the right solutions to solve their needs and give them a competitive advantage in worldwide market. To this end, they decided to develop a specific project for technology implementation and a first prototype fabrication: this is the genesis of Up-THERM project.
The main objective of the project is to perform a fundamental study of the novel heat engines and to demonstrate a prototype of the engine which is suitable as a prime mover for micro-CHP and mini-CHP systems. The main innovative character of the project is determined by the conceptual approach toward technological solution of the challenging problems of heat engines with external heat supply. This approach includes the use of working fluids changing phase, with crucial benefits: the working fluid, being incompressible, decreases remarkably dead volumes and their influence on the efficiency; there will be a substantial reduction of the dead volume permits using of external heat exchangers and thus to solve the scale up problem; heat transfer can be improved because of the boiling and condensation processes, and additionally engines with liquid working fluid can be made much safer since in operation volume of gas/vapor phase is smaller whereas out of operation a high-pressure gas phase can be absent at all.
The main objective of the project can be subdivided into the following tasks:
• To quantitatively study the shortcoming of the conventional and novel regenerative type heat engines.
• To perform a fundamental research of thermodynamics, heat transfer and fluid mechanical issues of the novel engines.
• Construction and testing of an engine prototype to prove the viability of the new engine concept.
This study should provide the technological know-how which will permit to develop an engine which could be used as a prime mover for micro- and mini-CHP applications with the following targets:
- Electric power output: 1-3 kW with a possibility of scaling up to few MW.
- Fuel or heat source: natural gas and concentrated solar thermal power.
- Thermal efficiency: not less than 40% of the Carnot efficiency, i.e. higher than 0.4 (1-TC/TH) where TC and TH are the temperatures of the cooler and heater, respectively.
- Engine cost in mass production: several times less than the cost of the available Stirling type engines of the same power (200-500 €/kW versus 2.500 – 4.500 €/kW).
- Projected maintenance free interval: 50.000 hour.
- Environmentally safe working fluid, such as water, air, carbon dioxide. Applicable for micro-CHP systems for houses.

Project Context and Objectives:
Up-THERM project main scope is to develop an innovative heat engine configuration, based on a regenerative heat converter with dense working fluids, being a simple and economical alternative to the state-of-the-art types of heat engines. Being an external combustion engine, the converter can use heat of any grade and origination, from fossil combustion and bio fuels, solar energy, to a low grade heat typical of Organic Rankine Cycle (ORC) engines.
Various safe and environmentally friendly liquid working fluids such as water or carbon dioxide can be used in the engine. The engine is noiseless and its operation is based on a unique cycle having the same efficiency as Carnot cycle and very simple, reliable and inexpensive design. As a result, cost per kW is much lower compared with that for contemporary IC, Stirling and Rankine engines.

The main S&T objectives of the Up-THERM are:
1. To quantitatively study and design the novel regenerative type heat engines.
2. To perform a fundamental research of thermodynamics, heat transfer and fluid mechanical issues of the novel engines, selecting the best engine fluid.
3. To fabricate and test an engine prototype to prove the viability of the new engine concept.

One of the objectives of the project is that of demonstrating the feasibility of the innovative heat engine configuration proposed by the SME Encontech. To reach this objective, the Up-THERM Consortium established a set of strategic objectives, of quantitative targets and of operative goals to be achieved with the new heat engine technology. In particular:
Strategic Objectives
S.O.1. Implementing a novel thermal converter, able to be efficiently fed by low temperature heat and by sustainable sources as solar, geothermal energy, biomass and waste heat.
S.O.2. Reducing drastically micro-CHP cost, penetrating a growing market currently stopped by the too expensive systems price.
S.O.3. Boosting the SMEs competitiveness, making available a revolutionary product to be proposed at a competitive cost.
S.O.4. Promoting the technology concept among the key audience and primary stakeholders, disseminating the key message that micro-CHP systems have huge potentialities in the European market thanks to a cost reduction and an energy efficiency enhancement.

Operative Objectives
O.O.1. To select the best engine working fluid.
O.O.2. To model the engine by means of a rigorous design tool, assessing the engine behavior within wide operating ranges.
O.O.3. To define the system functioning strategy.
O.O.4. To design the complete CHP system.
O.O.5. To fabricate and test a 1-3 kWel prototype, in order to demonstrate the feasibility and to assess the “on field” performance.
O.O.6. To evaluate the technology industrialization potentialities and to plan the market exploitation.

Starting from the structure of the project work plan, the specific objectives of each WP are reassumed below:

WP1 (REQUIREMENTS): The objective of this WP is the definition of the Up-THERM requirements and specifications which take into account all the regulatory, economic and technological perspectives relevant for the CHP applications.
WP2 (ENGINE MODELLING): The work package foresees the dynamic modelling of the thermodynamic cycle undergone by the working fluid inside the heat engine, and the main objective of this activity is the validation of the model that can be used for engineering design purposes.
WP3 (WORKING FLUID DESIGN): WP3 aims at applying an existing, integrated molecular-based platform to the problem of the computer-aided optimisation of the Up-THERM system (platform developed by ICON). The main objective of the WP is that of identifying a series of optimal working fluids for the new heat engine maximising its performance across a range of operational conditions.
WP4 (REGENERATOR DESIGN): The purpose of this WP is that of characterizing the regenerators, which are crucial parts of the engine, performing fundamental studies for working fluids with phase change.
WP5 (ENGINE EXECUTIVE DESIGN): Evaluations of different technical solutions and engine strengths calculations in this WP had the final aim of identifying the optimal executive design of the engine itself, which will be then manufactured and assembled.
WP6 (CHP PROTOTYPING): The main objective of this WP is that of implementing the CHP plant on the base of the executive designs made available in WP5, together with the development of a dedicated control system for the plant operation.
WP7 (PROTOTYPE TESTING): The start-up of the plant will be performed in WP7, and the tests phase planned in the DoW will be initiated, with the final aim of validating the Up-THERM technology and of verifying the effective engine performance against requirements.
WP8 (DISSEMINATION, EXPLOITATION AND TRAINING):WP8 is devoted to the definition of an exploitation route with all the partners, of an ownership agreement and strategy for the protection of the IPRs generated during the project, and to the realization and implementation of a dissemination plan for promoting the results obtained.
WP9 (CONSORTIUM MANAGEMENT): The Consortium Management WP has the main aim of carrying out the supervision of all the project activities, through specific tasks such as work planning, progress monitoring and re-scheduling in case of deviations, organization of general and technical meetings and communication with the REA (see sections in the following of this report).

Project Results:
The activities carried out in the project (M1 – M26 ) were mostly devoted to the achievement of the following results, from a technical point of view:
1. The Up-THERM requirements and specifications matrix has been defined, the user and system requirements tables have been organized in two different Deliverables, D1.2 and D1.3;
2. A detailed, high-fidelity dynamic model of the heat engine under study in the project, to be used for engineering and design purposes, has been developed, see D2.1;
3. The application of an existing, integrated molecular-based platform to the problem of computer-aided optimisation for the Up-THERM system has been assessed, see D3.1;
4. In parallel to the step above, a rigorous modelling of the engine regenerator was started, and provided first interesting simulation results.

1. The conclusion of the work initiated in P1 on the engine modelling and on the working fluid design carried out by the RTD ICON (WP2 – WP3);
2. The completion of the characterization of regenerators for working fluids with phase change, carried out at a lab scale by the RTD UT (WP4);
3. The performance of the design activities leading to the engine final drawings and manufacturing, led by the RTD performer UT under WP5;
4. The implementation of the complete Up-THERM CHP plant and control system development, carried out in P2 by the RTD LABOR (WP6) and the start-up and testing sessions activities (WP7);
5. A detailed set of dissemination actions and the definition of an exploitation plan agreed with all the partner SMEs; this work included communication related to the project, IP protection issues and training/know-how transfer activities (WP8).

From the point of view of the Management activities, the following actions have been performed during the whole project lifetime:
1. The preparation of the First and Second Periodic Report and of the related financial statements;
2. The creation of a Final Report showing all the developments carried out within the project framework;
3. The preparation of an agreed version of the Consortium Agreement, signed by all partners;
4. The submission of all the planned Deliverables for the project, and the supervision on their technical contents, on the base of what was originally planned in the DoW;
5. The planning and organization of general Project Meetings with all the partners, and the verification of the technical developments obtained by the RTDs in accordance to what is foreseen from the funding scheme, with an internal review procedure by the SMEs partners;
6. The management and coordination of internal technical meetings at WP level in order to monitor the status of the activities and to validate the results achieved;
7. The application of a contingency plan aiming at reaching the project goals and at recovering delays induced in the activities by unexpected technical difficulties with the prototype;
8. The preparation of official documents for the Amendment request for extending the project duration from M24 to M26;
9. The management of the overall communication flow during the project lifetime and of the relations between the partners to encourage collaborative atmosphere and fruitful work conditions for the obtainment of all the project objectives.

As illustrated in the work plan scheme, the project activities can be thought as structured in 3 main phases:
o Phase 1: Requirements/specifications identification and thermodynamic analysis → Activities performed in Period 1;
o Phase 2: Design of the working fluid, of the regenerator and of the heat engine → Activities performed in Period 1 and 2;
o Phase 3: Prototyping and testing of the Up-THERM CHP plant → Activities performed in Period 2;

The main results of each WP can be summarized as follows:

WP1 --------
In WP1, an evaluation of the potential application scenario for residential micro-CHP and an analysis of the market size in the different countries were delivered. The regulatory framework and the competition situation were also discussed. From a technical point of view, the most important user requirements for the operation of the device were outlined, from which it was clear that in domestic applications, any new technology like the Up-THERM one should be compatible with the central heating of the building. The technical choices related to the preliminary layout and the control system of the micro-CHP were also defined in this WP (see D1.3).

WP2 --------
The Up-THERM modelling framework from Task 2.1 was extended, refined and validated. In particular, the nonlinearities in the Up-THERM engine model were examined. Moreover, in order to get a better understanding of the heat transfer processes, small-scale experiments were planned and carried out in Task 2.2. The temperature profile along the displacer cylinder wall was measured. It was shown from the resulting experimental data that the shape of the temperature profile used in the engine model is an excellent qualitative representation of that expected in the actual device. Further validation of the model framework was undertaken against experimental data that was obtained at the Boreskov Institute of Catalysis (BIC) in Novosibirsk, Russia, by using an engine similar to the Up-THERM heat engine but with a different load.
Hence, a parametric study was undertaken as part of Task 2.3 followed by first-stage, manual attempt a local multi-parametric optimisation.

WP3 ---------
The sub-models for the prime mover parts were derived in this work package, as well as the details of the development of the SAFT-VR Mie thermodynamic equation of state as a methodology for working-fluid property prediction, with specific reference to the Up-THERM heat engine. A software tool linking the results from the fluid-property calculation with the dynamic model of the heat engine has also been developed, and with the aid of the GUI and SAFT-VR Mie, parametric studies were carried out on the current design of the Up-THERM heat engine to determine the best working fluid(s) and operating conditions for different heat sources.

In order to design a regenerator for the Up-THERM engine both simulations and experiments were performed in this WP. In the experimental setup a regeneration efficiency of 82% is achieved, where the theoretical maximum lies at 90%. This result can be considered as promising as the major part recoverable heat is actually recovered, i.e. 91.1% of the theoretical maximum.
A simulation is performed for the same pressure and temperature as measured during the experiments. The results of this simulations show excellent agreement with experiments based on the efficiency. Simulations for different parameters of the current regenerator design shows in which direction a better performing regenerator can be found. To obtain an efficiency higher than for the current design is unfeasible without increasing the total length of the regenerator. For the Up-THERM engine an appropriate set of regenerator parameters is suggested such that the internal volume and the amount of regenerator material is significantly reduced, while a similar performance is maintained.

WP5 ------
The executive drawings of the engine were produced in this WP. The partner SME ECT proposed a number of new engine concepts. From these concepts, as first step, the simplest one, which corresponds to the engine described in the project proposal (and which does not differ cardinally from the available engines) was selected. The main reason was to have a simple engine that would permit to study the basic engine processes and performance. One of the advantages of the engine is that different regenerators can be accommodated in the engine. An important advantage of the selected concept is that it resolves the problem of engine sealing and piston wear which is common for Stirling type engines. According to these drawings, the final Up-THERM engine was manufactured and integrated in a complete CHP plant for the testing.

WP6 ------
The work done under this WP led to the production of executive drawings for the final CHP plant including the novel Up-THERM engine. The system was designed to use natural gas as an input, so that a commercial boiler was used for the generation of heat. The complete plant layout, with heat exchangers, pipes, valves and the control system, was designed and then components were purchased for final assembly and preliminary testing at LABOR. Together with the hardware modules, the software for driving the control unit was created, debugged and tested in order to verify that all the parameters under study could be accurately measured. The plant was then started-up and the functioning of all the stages of the Up-THERM process verified.

WP7 -----
The testing session performed on the final micro-CHP plant was aimed at demonstrating the efficiency of the overall system under different operating conditions, driven through the control system integrated on the plant itself. The functioning of the prototype was verified against the requirements set at the beginning of the project, with the final aim of demonstrating the performance of the novel Up-THERM engine. The results of such tests were included in the final technical assessment report of the project.

WP8 -----
Effective and intense dissemination work was performed to duly promote the Up-THERM project to the external audience of stakeholders and end-users. These activities were mostly carried out by the SMEs, with the support, in some specific cases, of the RTDS (training sessions and scientific publications). Several materials for dissemination were created and diffused, and different contacts were established with the external to disseminate the project, as will be detailed in the WPs’ description in this report.

Taking into consideration the Milestones table as included in the Description of Work, we can state that:
a) MS1 – Engine Specifics was achieved at M3;
b) The thermodynamic model of the new Up-THERM engine was developed and used for an estimation of the engine performance (MS2 achieved at M12);
c) The working fluid selection for the engine was done with the aim of optimising the overall performance of the Up-THERM engine (MS3 achieved at M12);
d) The final, executive design of the engine was delivered and the engine manufactured for subsequent integration with the whole CHP plant (MS4 achieved at M20);
e) A test session was performed on the plant to verify and demonstrate the efficiency of the Up-THERM system with respect to currently available solutions (MS5 achieved at M26).

As a general consideration, and following the summary of the achieved results for the period above, we can state that:
o The project has achieved most of the strategic and operative goals set in the DoW, with some deviations with respect to the original work plan, that have been faced timely and with success.

o The technological choices and strategic decisions for the optimal execution of the project’s activities and research have been always presented and agreed to the SMEs within the Consortium; their involvement in the development of the project work has been precious and always encouraged;
o Delays were assessed in the course of the project that needed attention from the Management Board and the application of a contingency plan; the prompt reaction of the partners in managing the critical aspects of the research led to the fulfillment of the Consortium obligations towards the REA and to the satisfaction of the beneficiary SMEs for what concerns the expected results of the project, results that will foresee an engineering activity in a post-project phase with the final aim of introducing the Up-THERM technology in the target market (details in the Final PUDK).


------ Definition of requirements and specifications ---------
THE ACTUAL MICRO-CHP SCENARIO: Combined heat and power (CHP) technology was widely applied for many years in all activities characterized by high electric and thermal demands fairly constant and predictable, such as in the industrial sector. Since the most feasible applications (in terms of both primary energy saving and economic profit) for CHP in the industry scenario were already exploited, today the most interesting opportunity for CHP market diffusion seems to be in the residential sector. But the currently available CHP technologies for domestic application, which are based on internal combustion engines, do not have the characteristics of high efficiency, low cost, silent operation, low pollutant emissions and reduced maintenance, to render the CHP a real option to replace or integrate the traditional household boiler. The main micro-CHP systems currently available are based on ICE (internal combustion engine), MGT (micro gas turbine), FC (fuel cell), MRC (micro Rankine cycle), Stirling and TPV (thermo-photovoltaic) technologies. The latter three technologies are external combustion systems (thus, pollutant emission levels are comparable to those of boilers), characterized by high reliability, low noise, and potentially high values of the overall CHP efficiency.
Internal combustion engines are the most well-established technology for small- and micro-CHP applications. For residential application, the electric efficiency range is from 20% to 26%, with a potential CHP efficiency up to 90%. The range of power vary from a few kW to several MW.
The fuel usable in the ICE may be gaseous (very frequently natural gas, but also biogas) or liquid (mainly diesel but also vegetable oils derived from biomass) depending on the specific implementation. Reciprocating internal combustion engines are classified by their method of ignition: compression ignition (Diesel) engines and spark ignition (Otto) engines.
From a mechanical point of view in domestic applications the engine commonly used have a single-cylinder configuration which is cheaper and simpler than a multi-cylinder. A problem related to this configuration is the irregularity of torque. Furthermore, ICE needs some auxiliary systems like a lubrication system, an electronic control of fuel injection and flue-gas cleaning devices.
There are 3 sources, where usable waste heat can be derived from a reciprocating internal combustion based cogeneration system: exhaust gas, engine jacket cooling water, and with smaller amounts of heat recovery, lube oil cooling water. Heat from the engine jacket cooling water accounts for up to 30% of the energy input while the heat recovered from the engine exhaust represents 30–50%. Thus, by recovering heat from the cooling systems and exhaust, approximately 70–80% of the energy derived from the fuel is utilized to produce both electricity and useful heat. The primary pollutants associated with reciprocating internal combustion engines are nitrogen oxides (NOx), carbon monoxide (CO), and volatile organic compounds (VOCs—unburned, non-methane hydrocarbons). Other pollutants like sulfur oxides (SOx) and particulate matter are primarily dependent on the type of the fossil fuel and type of the engine used.

Gas turbines are a well-established technology for micro-CHP applications with electric power outputs higher than 30 kW. The major technical factors that challenge the development of micro turbines of a few kW are related to the small-scale effects (e.g. large fluid dynamics, heat and mechanical percentage losses) and costs. Studies to increase the MGT electric efficiency focus on ceramic materials and hybrid power plants consisting of an MGT integrated with a solid oxide fuel cell.
The MTG on the market present a power size ranging from 30 to 200 kWe with an electrical efficiency of 25÷30 % about. MTGs are often fed by natural gas but some of them are fuelled by LPG, biogas, propane, diesel oil and coal oil. Micro-turbines offer a number of advantages when compared to reciprocating internal combustion based cogeneration systems. These include compact size, low weight, small number of moving parts and lower noise. In addition, micro-turbine based cogeneration systems have high-grade waste heat, low maintenance requirements (but require skilled personnel), low vibration and short delivery time.
Due to their simple construction and few moving parts, micro-turbine systems have the potential for lower maintenance costs than that of reciprocating internal combustion engines. Normally, scheduled maintenance is carried out every 6000÷8000 operative hours, with maintenance costs in the 0.006–0.01 $/kWh range (0.0044-0.0074 €/kWh). An overhaul is required every 20,000–40,000 h depending on the product developers, design, and service. A total lifetime is estimated about 60000 ÷ 80000 hours.

The micro-CHP systems based on Rankine cycles (which use water or an organic fluid as the working fluid) with a power size up to 10 kW, which are mostly available on the market at a prototype level only, have an electric power size ranging from 1 kW to 10 kW and a corresponding thermal power size ranging from 8 kW to 44 kW. For this reason, they may represent a good alternative to household boilers. The electric efficiency ranges from 6% to 19%, with a potential overall CHP efficiency always higher than 90%.
The working fluid of MCR can be water but, more often, an organic fluid is used. In this case, the cycle is called Organic Rankine Cycle (ORC). The MCR for residential applications, although already available from some manufacturers, are still not very common. Therefore, it is difficult to estimate the actual costs of investment and maintenance costs, as well as the effective useful life. If we consider a turbo-generator with a power size of more kW the cost is about 900÷ 1600 € / kW (specific cost increases while power size decrease, the total cost of a system, including the boiler, pipes and civil works, is estimated to be about 4 times the cost of the turbo-generator).

Stirling engines are beginning to stage a comeback to the market since the development of the modern ‘free piston’ Stirling engines. The technology is not fully developed yet, and it is not widely used; however, it has good potentiality because of its ability to attain high efficiency, fuel flexibility, low emissions, low noise/vibration levels and good performance at partial load.
Unlike reciprocating internal combustion engines, the heat supply is from external sources, allowing the use of a wide range of energy sources including fossil fuels such as oil or gas, and renewable energy sources like solar or biomass. Since the combustion process takes place outside the engine, it is a well-controlled continuous combustion process. Stirling engines have low wear and long maintenance free operating periods, and are quieter and smoother than reciprocating internal combustion engines.
The micro-CHP Stirling systems available on the market with an electric power size of up to 10 kW, which are mostly prototypes, have an electric power size ranging from 1 kW to 9 kW and a corresponding thermal power size from 5 kW to 25 kW, which may also represent a good alternative to household boilers. The electric efficiency ranges from 13% to 28% with the CHP efficiency higher than 80%, which may even go beyond 95%. Other alternatives to the micro-CHP technology can be considered TPV generators and fuel cells.
The engines proposed combine most of advantages of the newest heat engines, great simplicity, quite simple operation and use of heat sources such as solar energy, waste heat, biomass derived products. Mechanical energy generated can be converted not only to electricity but can also be used for compression of gases, pumping of liquids, driving of coolers and heat pumps, etc. Respect to the overview of the currently available solutions, the main advantages of the Up-THERM technology are expected to be:
• very simple design;
• low costs;
• long lifetime;
• high reliability;
• compactness and great fuel flexibility;
• small energy losses and therefore higher energy efficiency compared to the available systems is expected in micro and mini power ranges.
The study performed in the project identified the technological know-how allowing to develop an engine which could be used as a prime mover for micro- and mini-CHP applications with the following target performance:
• Electric power output: 1-3 kW
• Fuel or heat source: natural gas (with the possibility to use biomass or heat from a solar concentrator)
• Thermal efficiency: not less than 40% of the Carnot efficiency, i.e. higher than 0.4(1-Tc/TH)
• Projected maintenance free interval: 50000 hour.
• Environmentally safe working fluid, such as water (the engine can work also with organic fluids)

USER REQUIREMENTS: The Deliverable produced in WP1 of the project on user requirements had the final purpose of collecting and organizing the requirements coming from the potential end-users representing the application scenario described and selected in D1.1. Given the high commercial interest of the Consortium SMEs, our attention in this document was focused on the needs and interests of the players of this sector, collected on the base of the possible use cases.
ECT, in collaboration with NE, EFICEN and the support of LABOR identified the user requirements focusing on the use case scenarios identified and described in D1.1. These user requirements are distinct from system requirements in that they do not imply any particular solution but simply state the problem or challenge for which the users require a solution. This task represented an important analytical effort to understand the actual needs of the sector, in order to guide the search for and the assessment of possible solutions without focusing on any particular solution too early. An important purpose of the user requirements is to have technology independent criteria to guide the search for, assessment and selection of candidates for technological solutions and there subsequent evaluation irrespective of their concrete implementation.
For the purpose of the project, as mentioned above, we have taken into consideration only the application identified in Deliverable D1.1 , which best fits the strategic interests declared by the beneficiary SMEs in the Up-THERM Consortium, that is, decentralized micro-combined heat and power production in residential sector.

This choice was due to two main reasons. The first is related to the potential market all over the Europe countries which justifies the strong interest of the SME. In Europe the largest part of energy consumption is due to the residential and the tertiary sector. The second is due to the technical characteristics which the prototype will have that make it suitable for domestic application. These characteristics are the rated power both for electric and thermal output, great reliability and simplicity, low operative costs (due to the possibility to use not fine fuel as biomass , more cheap than natural gas), low start-up cost and an easy implementation in domestic facilities. The target markets in Europe for this application are detached or semi-detached houses with a floor area and therefore an energy demand slightly greater than the average value for the considered countries. This kind of dwelling justifies better than the others a possible investment of a household for a micro CHP-system. From the technical point of view, in contrast to the available micro-CHP, the new system is expected to be the most suitable in the micro power range of about 1 kW.
Residential sector has a wide range of dwellings. Only some of them represent a good market for the micro CHP application. Their characteristics are summarized here:
• Habitable > 120 m2
• Mono or bi-family unit
• Parted from other buildings
• Average degree days : from 2000 to 3000 dd
• Total thermal energy for heating and DHW (domestic hot water) from 15000 kWh/y to 30000 kWh/y
• Total electric energy from about 3000 kWh/y to 5000 kWh/y if we consider the use of air conditioning system.

Defining user requirements – the needs of the stakeholders who will directly interact with or benefit from the system to be developed – is without doubt one of the most difficult challenges in building complex systems. When it comes to defining user requirements for any research project, it is essential to use models to document and analyze the requirements. Following good requirements modeling practices is a key to success in the requirements development, since it can accelerate the phase of engaging the end-users and stakeholders who should provide the relevant information, and thus allowing for the gathering of highly complete, clear and consistent user requirements.
According to these suggestions, the Up-THERM Consortium proceeded in an iterative way in the development of the User Requirements, and developed the related deliverables further until the definition of the SMEs’ needs and interests will be completed.
The Consortium was able to draft the indications on how a novel engine for micro CHP system should work, and how should this provide an advancement with respect to the existing micro CHP system. The requirements analysis included 4 types of activities:
1) Identifying the various types of requirements from various sources including project documentation, business process documentation, and stakeholder interviews.
2) Analyzing requirements to be sure they are clear, complete, consistent and unambiguous.
3) Recording and organizing these requirements in a document.
4) Receiving feedback from the customers.
The results of these activities were extensively reported in D1.2.

SYSTEM REQUIREMENTS: The work performed during WP1 to elaborate and organize the system requirements had the final aim of assessing a complete, consistent and clear set of requirements through which the different components of the system could be outlined, and the related specifications gathered for the system implementation during the project. As introduced in the User Requirements deliverable (D1.2) the information collected did not specify a concrete implementation direction, but provided measurable criteria for judging whether any given specification meets the fixed requirements. The first step was then to select a coherent subset of requirements from D1.2 that Up-THERM will address. This selection depended both on the project’s feasibility evaluation regarding different technological options and on the prioritization of requirements by the users. For the four sub-systems of the Up-THERM device, requirements have been organized as:
• Th.In.Req.i (Thermal energy input)
• En.Req.i (Engine)
• El.Out.Req.i (Electric energy output)
• Th.Out.Req.i (Thermal energy output)
Firstly, each requirement was classified as Critical, Wanted, Preferable or Wished. A requirement tagged as Critical represents the perception that it is a necessary one. Preferable requirement reflects the perception that it is something that it would be better to implement. Then a priority level was assigned (High/Medium/Low) with the scope of helping developers to make trade-offs between features just in case of conflicts. This methodology allowed to minimize the number of difficult choices requiring a direct comparison between users/customers and designers/developers. For each requirement, users and developers should agree on what it is necessary to be in place at a given time.

The technical choices made in D1.3 show the layout of the micro-CHP system and of its control system. The main characteristics to select in the preliminary layout were related to the steam generator (which we named simply as boiler), the engine parameters and the working temperature of the heating system. The features for the control system were related to the control concept heat-led, electricity-led or price-based (demand response).

-------- Engine modelling and working fluid design ----------
Up-THERM ENGINE MODELLING: Under WP2, Task T2.1 the heat engine was split into suitable components, or compartments. For each component the dominant physical process (fluid flow or thermal) was modelled dynamically. These sub-models were then combined to form a model framework for the thermodynamic cycle of the Up-THERM heat engine.
During Task 2.1 two components of the heat engine were confirmed as being crucial for the modelling of the engine. These two components are the heat exchangers (this was already suspected ahead of the project) and also a valving arrangement that is formed and governed by the design and relative motion of the piston within the displacer cylinder. This action is inherently nonlinear, whereas the thermal processes mentioned above can be modelled either linearly or nonlinearly. Although the proposal description for Work Package 2, and the resulting Description of Work for the Up-THERM project, explicitly suggest the linearised modelling of the Up-THERM engine, ICON decided that the work in this work package would not only consider the linear equivalent processes as stated therein, but would go well beyond this, thus extending the initial scope of work to include the development of a dynamic nonlinear model of the engine. To obtain the nonlinear model of the Up-THERM heat engine, the linear sub-models of these two components were replaced by nonlinear sub-models. The development of both linearised and nonlinear descriptions of the processes that take place in these two components allows the capture in more detail of the operation of the device, and a more realistic prediction of ultimate performance.
As a general consideration, the heat engine in the Up-THERM project belongs to a class of unsteady vapour-phase heat engines referred to as “two-phase thermofluidic oscillators” (TFOs). When a steady temperature difference is applied across a TFO, the working fluid within this device experiences sustained pressure and temperature oscillations, while undergoing phase change. During the heat addition (evaporation) phase of the cycle the working fluid is evaporated and the mass of vapour within the device increases. This leads to an increase in pressure, due to the higher specific volume of the vapour phase, and a subsequent positive displacement stroke into a load. Conversely, during the heat rejection (condensation) phase the vapour mass decreases and the pressure decreases, leading to a suction stroke. The displacer and liquid pistons in the device, as well as any other interconnected components, are used to transfer these pressure and volume oscillations to the load at one end of the device. Ultimately, these alternating changes (oscillations) in pressure/volume can be harnessed to drive a generator at the load, where work can be extracted.
A schematic of the engine is shown below. On the left hand side is the displacer cylinder which consists of a gas spring at the top and the hot heat exchanger below it. Below that is the cold heat exchanger. It is formed of loops filled with cold water running around the cylinder. In the displacer cylinder is the displacer piston which is connected to a mechanical spring. The mechanical spring is fixed to two points in the displacer cylinder. The piston forms with the displacer cylinder a valve, which closes and opens alternately. On the right hand side is the working cylinder with a gas spring at the top. Displacer and working cylinder are connected by the connection tube. In the connection tube is the load, formed of a solid piston with a connection to a device outside the engine.
The engine is filled with working fluid. The gas spring in the working cylinder comprises air. The working cylinder, connection tube, and displacer cylinder are filled with liquid working fluid. The gas spring in the displacer cylinder (above the displacer piston) comprises working fluid in the vapour phase.

MODELLING APPROACH: one example of a Thermofluidic Oscillator (TFO) is the “Non-Inertive-Feedback Thermofluidic Engine” (NIFTE) (Markides and Smith 2011, Solanki et al. 2012, Solanki et al. 2013). A modelling framework for the NIFTE was developed previously and the efficiency and frequency have been calculated for this model. The results were compared to experimentally acquired data.
The Liquid Stirling Engine (LSE), owned and developed by Encontech, is another example for a TFO. Given the similarity between these two class of devices, the development of the model for the Up-THERM has followed the same approach that was used to model the thermodynamic cycle of the NIFTE. In the Up-THERM project, the LSE is used as a basis for the modelling framework that ICON is developing as part of Work Package WP2. One particular prototype of this technology is also currently being tested at the Boreskov Institute of Catalysis (BIC) in Novosibirsk, Russia (A. Samoilov 2013).
In the chosen approach, a set of suitable, first-order linearised and spatially lumped, ordinary differential equations (sub-models) are derived for every component (displacer piston, connection tube, heat exchangers, etc.), each describing the dominant thermal (ΔT-s) or fluid flow (ΔP-u) process taking place in that component.
Analogies are drawn such that the differential equations governing the dynamic processes are represented by passive electrical elements (resistors Ri, capacitors Ci, inductors Li); resistors are used to describe heat transfer or viscous drag, inductors represent the inertia of oscillating fluid columns or pistons, and capacitors describe hydrostatic pressure and vapour compressibility.
OUTPUT OF THE MODEL: The model is capable of producing a number of important outputs. On entering relevant device parameters, and external conditions applied to the device, the framework is then able to evaluate operation (oscillation) frequency, the amplitude of important variables (pressures, flow rates, displacements) as well as a range of performance indicators, such as the useful power output, the heat input, the exergetic efficiency, and the thermal efficiency. Additionally the state variables can be plotted as a function of time, which allows inspection not only of the amplitudes of oscillation of important variables such as pressures, but also of the phase differences between these variables.
In the modelling approach used in ICON’s work, the Up-THERM heat engine was segregated into its key single components and/or compartments. The dominant process in each component/compartment was described by using first-order linearised and spatially lumped ordinary differential equations. Analogies were drawn such that the differential equations governing the dynamic processes are represented by passive electrical components (resistors, inductors, and capacitors). The single components were then interconnected in the same way as in the physical device.

REFINEMENT AND VALIDATION OF THE MODEL: The modelling of the nonlinear valve that is formed between the displacer cylinder and the piston inside the cylinder has been further investigated in WP2. Initially, and as reported in our previous interim report, the valve was modelled using a Heaviside step function. Instead of the Heaviside step function an approximation of this function can be used.
From experimental results that were obtained at the University of Twente (UT) it was suggested that the equalisation of pressures below and above the valve is almost instantaneous after the opening of the valve. That implies that a step function can be considered as a suitable model for the valve. This is also in agreement with the project partners from UT.
The model was further extended by adding the slide-bearing segment of the piston. In the slide-bearing segment, the fluid flow flows through two thin channels, which are separated from the piston. The piston moves through a third channel and is in (almost) no contact with the fluid.
The Up-THERM model was validated against two sets of data, both generated at the Boreskov Institute of Catalysis (BIC) in Novosibirsk, Russia. The engine that is being used at BIC is similar to the engine being developed as part of the Up-THERM project.

MODEL WITH AND WITHOUT LOAD: The difference between the two engines compared in this work was in the description of the load. Therefore, in the first step of the validation process the model framework was validated against experimental data without a load. This means that in this step the load was omitted in the model.
The engine comprises the displacer cylinder with the displacer piston, hot and cold heat exchanger, connection tube, and working cylinder with gas spring. In this case, the heat input to the engine is only used to overcome losses in the engine (e.g. friction), as no work is extracted during operation.
In a second step the load that is being employed at BIC was modelled and incorporated into the Up-THERM model framework. This allowed operational and performance predictions from the models to be compared directly to data from BIC. The load comprised a check valve that allowed fluid flow only in one direction. A second valve was placed in parallel to the check valve whose resistance could be regulated such that different load variations could be applied. This valve also contained a check valve.

EXPERIMENTAL SETUP: In the course of this WP, ICON conducted small-scale experiments with the aim of getting a better understanding of the heat transfer processes that take place at the top of the displacer cylinder in the Up-THERM heat engine.
Specifically, the temperature profile along the cylinder wall was of interest. The cylinder was constantly heated at the top by an electrical heater and cooled at the bottom by a stream of water. A pneumatic actuator moved the piston vertically within the cylinder. Inside the cylinder pentane evaporated when the liquid-vapour interface was in contact with the hot surfaces, and condensed when then interface was in contact with cold surfaces.
The experiments cannot be considered as prototyping of the engine as only one part of the engine is represented in the experiments. Therefore, the results that were obtained from the experiments had to be carefully examined and evaluated. The knowledge from this evaluation could then be transferred to the engine model and included in the framework.
As mentioned before, only one part of the engine was represented in the experiments. The components which were included were:
• Heater/cooler
• Displacer cylinder
• Piston

RESULTS OF THE 3 MEASUREMENTS CYCLES: In Work Package 2/Task 2.2 the Up-THERM modelling framework from Task 2.1 was extended, refined and validated. In particular, the nonlinearities in the Up-THERM engine model were examined. These are the valve, which is formed between the piston and the walls of the displacer cylinder, and the temperature profile imposed by the heat source and sink on the heat exchanger walls at the top of the same cylinder. A further additional nonlinearity arises externally to the Up-THERM device, in the hydraulic load, which comprises non-return flow valves.
Moreover, in order to get a better understanding of the heat transfer processes, small-scale experiments were planned and carried out in Task 2.2. The temperature profile along the displacer cylinder wall was measured. It was shown from the resulting experimental data that the shape of the temperature profile used in the engine model is an excellent qualitative representation of that expected in the actual device.
Further validation of the model framework was undertaken against experimental data that was obtained at the Boreskov Institute of Catalysis (BIC) in Novosibirsk, Russia, by using an engine similar to the Up-THERM heat engine but with a different load. This attempt consisted of several steps. In a first step the engine was operated without a load. In this configuration the pressure amplitudes were described well by the engine model. The second step involved including a load in both physical and model systems.
Experiments were undertaken at two different backpressures: 5 bar and 9 bar.
It was observed that the general trend of the pressure amplitudes was described well by the model, although the height of the amplitudes differed.
The validation serves as proof that the engine model framework is capable of semi-qualitatively describing the pressure oscillations in the engine well. The frequency which was calculated by the model was higher than that observed in the experiments, which may be due to the operating conditions employed in the tests at BIC, or the intricacies of the BIC engine that may not be entirely as described by the engines being designed for the Up-THERM application.
Having further developed our Up-THERM model and attempted to validate this with experiments and data supplied by BIC, an effort to perform an early-stage engineering design of the Up-HERM heat engine cycle was made. Hence, a parametric study was undertaken as part of Work Package 2/Task 2.3 followed by first-stage, manual attempt a local multi-parametric optimisation. Three physical dimensions, namely the height of the gas spring and the diameters of the connection tube and liquid column in the displacer cylinder, were identified as those parameters with the greatest influence on the Up-THERM engine performance. It was shown that by making combined changes to the values of these three physical dimensions, the power output and the efficiency could be influenced very significantly. This led to power outputs of the order of 12 kW and thermal efficiencies of about 0.8%.

USE OF THE SAFT METHODOLOGY: In WP3, the partner ICON developed a design tool capable of bringing together: (1) accurately calculated thermodynamic properties of a working fluid specified by the designer undergoing the thermodynamic cycle in the Up-THERM heat engine; along with (2) the description and predictions of the operation and performance of the Up-THERM engine. Therefore the aims of Work Package 3 were to: (1) develop a computer-based tool for the design of the Up-THERM engine that is based on the dynamic model of the Up-THERM developed in Work Package 2; and to add to this (2) a capability of using different working fluids (including mixtures), based on a world-leading thermodynamics property prediction tool, Statistical Associated Fluid Theory (SAFT).
In light of this, the SAFT-VR Mie equation of state, an advanced version of SAFT, was used by the ICON team to develop molecular-based thermodynamic models for members of the straight chained alkane homologous series. The calculations from SAFT-VR Mie have been validated against the available experimental data available from the National Institute of Standards and Technology (NIST) thermodynamic database. The SAFT-VR Mie equation of state is used to calculate the fluid properties necessary for the operation of the heat engine.
A large number of working fluids are available for deployment in typical heat engines, the permutations of these working fluids increases exponential when mixtures of working fluids are considered. Hydrocarbons have been proven efficient as working in low to medium temperature heat recovery engines such as Organic Rankine Cycles and solar engines (Angelino and Colonna Di Paliano, 1998; Wang et al., 2010). The molecular models described in WP3 reports were used for the calculation of the thermophysical properties of the alkanes considered. The thermophysical properties of interest (for the operation of the Up-THERM engine) include the saturation temperatures and pressures; the saturation densities and volumes of the liquid and vapour phases; the enthalpies of evaporation; the entropies of evaporation; and the heat capacity ration of the vapour phase.

THE UP-THERM ENGINE SIMULATION PLATFORM: The engine simulation platform is a graphical user interface that consolidates the working fluid properties calculated with SAFT-VR Mie with the dynamic model of the Up-THERM heat engine. The thermodynamic properties of the single (and mixture) working fluids derived with SAFT are stored in a property database; the Simulator accesses this database for the necessary working fluid properties and passes it on to the engine program whenever the dynamic simulation of the heat engine is required.
The Simulator contains various options for designing the choice of the working fluid; the engine operating conditions; the temperatures of the heat source and heat sink; and the physical (both external and internal) description of the heat engine. On successful completion of the Simulation, the Simulator extracts the results and performance indicators from the program and provides options for the output format of the results; either in graphical or numerical such that the user can access and store results in the preferred format.
The input section enables the user to supply all the necessary information required as inputs to the engine program. This comprises the working fluid design, the heat exchanger specifications, the engine operating conditions, the internal and external description of the engine and a characterisation of the engine load. The output section contains the options for running a single simulation or a parametric simulation, the display of the simulation results and options for plotting and exporting the results.

WORKING FLUID DESIGN: the selection of the working fluid to be used for the engine simulations can be selected. The single working fluids presently available at present are water and the alkanes from butane to decane, while working fluid mixtures of butane and decane are also available. Selecting either of ‘Single Working Fluid’ or ‘Working Fluid Mixture’ enables the user to select from the list of single working fluids or to select from the list of butane composition in the fluid mixture respectively.
The physical design of the engine components also serve as inputs to the programs. Thus the user can also edit these dimensions. Once the working fluid is designed and the necessary engine parameters are entered, the Simulator is ready to run the engine program. When the user selects the Simulator buttons, the Simulator checks the inputs for errors and consistency; it returns to the user if there are any errors that would prevent the successful completion of the simulation, otherwise, it would use the values set by the user for the simulation.
The key performance indicators of the Up-THERM heat engine are displayed in the ‘Engine Output’ section of the user interface. This contains the values of the engine’s oscillation frequency, power output, thermal and exergetic efficiencies. A drop down list is also provided for visualising the pressure-volume variation in the heat exchanger and in the load. It should be noted that the present engine contains undefined loads thus, the resistances and inductances of the load have been set at arbitrary values.

COMPARISON OF WORKING FLUIDS: The procedures earlier described pertain to the case when a single simulation case is selected by clicking on the ‘Single Run’ push-button. The parametric simulation button however provides the facility to enable the user to investigate the effects of variations in the operating conditions on the Up-THERM engine. One may decide to investigate the response of the heat engine to varying operating pressures, choice of working fluid, engine dimension and piston characteristics etc. selecting the ‘Parametric’ push-button opens the parametric simulator dialog screen. In summary, having successfully developed the SAFT-VR Mie methodologies and the GUI link between its result and the dynamic model of the Up-THERM heat engine, further studies will be carried out (in-line with the definition of Task 3.2 in the Description of Work) to design an optimal working fluid for the engine at some specified operating condition. This will involve a parametric study of a number of known potential working fluids and the mixtures of the most promising selections. This approach would then be expanded to design intelligent working fluids for the engine that would enable the engine to operate efficiently over a varied heat source temperature.

------ Regenerator design and testing --------
REGENERATOR DESIGN: In the course of WP4, the design of the regenerator of the Up-THERM engine was developed by UT. To this end, the performance of the regenerator is studied both theoretically and experimentally. This research will lead to a tool that can predict the regenerators efficiency based on several geometrical design parameters and the operating conditions.
In the Up-THERM project a novel heat engine is developed based on a dense working fluid. It is considered as a simpler and cheaper alternative for existing machines in the power range up to 1 MW. An important part of this engine is the regenerator, where during a cycle heat of the working fluid is temporally stored and later used for heating of the fluid. During the cycle of operation cold fluid enters the heating circuit. It flows through the regenerator, where heat from the solid matrix is transferred to the fluid. The temperature will gradually increase in the axial direction.
By achieving a high level of regeneration the overall efficiency of the Up-THERM engine is increased. An accurate model describing the heat transfer and phase transition phenomena is needed to assist in designing a regenerator for the Up-THERM engine. The theoretical study on the regenerator within the Up-THERM engine was presented, which led to a numerical tool to predict the efficiency as function of several geometrical parameters and operating conditions.

The experimental setup for the tests was created to assist in the design of the regenerator for the Up-THERM engine. By evaluating experimentally the heat transfer rate and/or the regenerator's efficiency the design parameters can be chosen such that the performance of the engine is optimized. In order to provide some more background on the working principle of the regenerator its functioning is described first.
During the cycle of operation cold fluid enters the heating circuit. It flows through the regenerator, where heat from the solid matrix in transferred to the fluid. The temperature will gradually increase along the axial direction. As the fluid exits the regenerator some additional heat is provided by the heater in order to have a fluid at the high temperature, , which will be maximally 400 Cº. During the other part of the cycle hot fluid enters the regenerator where it is now cooled down by the solid matrix. Gradually, the temperature decreases along the flow direction and at the exit of the regenerator the fluid is further cooled to the low temperature, , which will be the ambient temperature.

• Downward motion - During downward motion of the piston, which is precisely controlled by a hydraulic actuator, cold fluid is forced through the heating circuit, where it is heated and expanded. This causes the pressure to rise. When the pressure inside the system reaches a value above that of the high pressure accumulator, fluid will also flow to the load system, where it performs work.
• Upward motion - After reaching the lowest position, the piston will move up again and high pressure, hot liquid is forced through the external heating circuit towards the cold part of the test setup. Now the fluid is cooled and the density increased, causing a decrease in pressure. As soon as the pressure drops below the pressure of the low pressure accumulator, fluid from the load system flows back into the `engine’.
• Operating conditions - The maximal operating conditions are 400° C and 150 bar. Such conditions are relatively easy as no high temperature metal alloys are needed and standard piping can be used. These conditions allow for an interesting temperature and pressure range for CO2, which will be the working substance. Using CO2 provides certain benefits compared to water. Thermodynamically, it is more interesting to use CO2 as a higher level of regeneration is possible. It also circumvents the problem of air bubble entrainments that is experienced when using water as working fluid. In a well-ventilated room CO2 is not hazardous.
• Determining the efficiency - Both the pressure and the temperature of the fluid will be monitored during an experiment. It is assumed that the pressure drop over the regenerator is limited, such that the pressure measured at the cold side of the regenerator can be used to determine the state of the fluid at the hot end. The temperature and pressure data provide the increase in enthalpy of fluid while flowing through the regenerator. Comparing this increase in enthalpy to the total gainable enthalpy increase provides the efficiency of the regenerator.

Measurement data collected from the test setup mostly consisted of temperatures, pressures, flow rates and electrical power input.

• Temperatures - The temperature is measured at multiple locations on the outside of the regenerator as well as in the flow on both exits using thermocouples. Furthermore, the temperature inside the channel of the heater and cooler was monitored to control the temperatures in both heat exchangers to fixed values. K-type thermocouples with a diameter of 2 mm are used, which have a typical accuracy of 1-2°C.
• Pressures - The pressure is measured in the cold part of the test setup using a pressure transducer (Hydrotechnik, up to 250 bar). The pressure in the accumulators will be measured using analog manometers. Fast fluctuations can be captured using this sensor; up to 10 kHz with an accuracy typically within 2%.
• Volume flow - After the check valve on the high pressure side of the load system a volume flow meter (water-flow meter, Hydrotecknik QT200, 0.10L/min) is installed. Together with the prescriber motion of the piston the flow rates in the setup can be determined.

• Electrical power - The power dissipated by the electrical heater is monitored by measuring the voltage and the current applied to the heater. This metering device is connected in between the controller and the heater.

The design of the test setup has been finalized and all parts are ordered. With the exception of the regenerator all parts are ready. The regenerator outer shell is currently being manufactured as well as the first insert that will be used for preliminary tests. When the last parts are ready the setup will be assembled and filled with liquid CO2 and test can begin.

EXPERIMENTAL STUDY ON THE REGENERATOR: The experimental setup in which the regenerator of the Up-THERM engine is tested is described in D4.3. The schematic overview of the setup is depicted below. The main function of the setup is to create an alternating flow through the regenerator with a high pressure during the heating phase and a low pressure during the cooling phase. In this way the flow through the regenerator in the actual heat engine is mimicked. Both the temperature and the pressure can be set to realistic values that correspond to actual applications.

RESULTS OF TESTS ON THE REGENERATOR: Within the time span of the Up-THERM project, UT managed to perform an actual regenerator experiment with high pressure (100 bar) at elevated temperature (100°C). First, the actual settings were discussed. Subsequently, the raw data were shown and interpreted and finally, the regenerator efficiency was determined from the raw data.
Several constraints of different type limit the maximum operating temperature and pressure.
The pressure is limited to 150 bar for safety reasons. During operation water from the low pressure accumulator will be displaced into the high pressure accumulator, raising the pressure in the high pressure accumulator. To be sure that the maximum pressure is not exceeded the initial pressure of both accumulators is set to 95 bar. The temperature of the heater cannot exceed 200 °C. The sealing between the heater and the cylinder is ensured by a Viton O-ring which is rated up to this temperature. In order to be on the save side, the electrical heaters on the outside of the aluminium element are set to this maximum temperature of 200 °C.
The cold temperature of the system is determined by the temperature of the tap water. During the experiments this was 13 °C. The operating frequency was set to 1 Hz. The stroke of the piston was set to 17 mm. Due to the unavailability of the proper sealing material a larger stroke resulted in too much leakage of CO2, which would affect the measurements.

• Downward stroke - A clear oscillatory behaviour of the pressure inside the setup can be observed. This pressure fluctuates between pressure of the high and low pressure accumulators. During the downward stroke, e.g. 0.0 < time < 0.5 the CO2 is displaced from the cold space of the engine through the cooler, regenerator and the heater into the hot space. The expansion causes the pressure of the CO2 to increase up to the pressure of the high pressure accumulator. As soon as this pressure is overcome CO2 is displaced into the load circuit and a peak in the flow rate is observed. The CO2 pressure remains fairly constant during this stage.
• Upward stroke - During the upward stroke, e.g. 0.5 < time < 1.0 the hot CO2 is displaced into the regenerator and the cooler, where its density decreases. The pressure of the system decreases and as soon as this pressure drops below the pressure of the low pressure accumulator CO2 flows back from the load circuit into the engine.
• Temperatures - During the downward stroke cold CO2 enters the regenerator. Inlet temperature decreases to 23 °C. The temperature at the outlet also decreases from 100 °C to approx. 65 °C. The rather constant temperature difference between the inlet and outlet is the part that is being regenerated. The CO2 has to be heated up to the maximum temperature of 100 °C and a significant fraction of this heating is done by in the regenerator. During the downward stroke a similar behaviour is observed for the cooling of the CO2. First the CO¬2 temperature at the inlet is increasing up to the maximum temperature of 100 °C. The CO2 is not completely cooled down to the lowest temperature, but also here a significant portion of the heat exchange is performed in the regenerator.
The temperature at the inlet of the regenerator is not immediately the temperature equal to the extreme temperature. First CO2 at a temperature equal to the exit temperature from the previous half period enters the regenerator. Then the temperature increases rapidly to the temperature of the (interior of the) heater.
Efficiency - In order to determine the efficiency of the regenerator the enthalpy gained by the CO2 inside the regenerator must be compared with the maximum enthalpy difference between the cold and hot conditions. During the downward stroke (e.g. 0.0 < time < 0.5) CO2 with a specific enthalpy corresponding with the lower black line enters the regenerator from the cold side. At the same moment CO2 with a specific enthalpy corresponding to the upper black line flows out of the regenerator on the hot end. This increase in specific enthalpy is indicated by the black upward arrow. When the regeneration would be ideal, and the temperature at the exit would be equal to the maximum temperature of 100 °C, the increase in specific enthalpy would be as indicated by the grey upward arrow. The instantaneous efficiency is therefore defined as the ratio of the length of the two arrows. During the upward stroke (e.g. 1.5 < time < 2.0) the efficiency is defined similar. The actual decrease in specific enthalpy is indicated by the black downward arrow and the maximal decrease by the grey downward arrow. The efficiency is here also defined by the ratio of the two.
At the beginning of a heating stage the efficiency is almost equal to 100% as hot CO2 which has just entered the regenerator now leaves the regenerator. The efficiency then drops rapidly but seems to stabilize at a value of about 73%.
It is clear that a considerable amount of heat can be regenerator with the currently used regenerator design. With a regeneration of 82%, 82% less energy input is required from the heater, compared to running the engine without a regenerator. The results obtained so far are quite satisfactory for the first Up-THERM engine design. In order to be able to improve the design, the simulation program can be used.

CONCLUSIONS: In the experimental setup a regeneration efficiency of 82% is achieved, where the theoretical maximum lies at 90%. This result can be considered as promising as the major part recoverable heat is actually recovered, i.e. 82/90=91.1% of the theoretical maximum.
The pressures obtained in the setup are representative for realistic applications. The temperature in the regenerator is only moderate since higher temperatures are foreseen in the actual application. However, it is expected that the current results can be extrapolated to higher temperature.

----- Up-THERM engine design and manufacturing ----------
SKETCHES OF THE ENGINE COMPONENTS: The initial design of the Up-THERM engine has been drafted in D5.1 produced by UT. This indicates:
• Mechanical output (purple)
o In this design piston is connected to a shaft using a ‘Skotch yoke’ mechanism, which turns the linear motion of the piston in to rotation of the shaft.
• Hot compartment (red)
o The hot compartment in located above the piston. The heat is supplied through the steel cylinder wall. The fluid flows through the narrow gap between the cylinder and the piston from the regenerator to the hot compartment and vice-versa. The long narrow gap is used to separate the hot compartment from the rest of the engine, limiting heat transfer by conduction, and to have a rather large area available for heating up the fluid along its way up.
• Regenerator (yellow)
o The middle part of the piston contains a hollow space which is reserved for the regenerator. Here, a custom made regenerator can be placed.
• Cold compartment (pale blue)
o All the working fluid located below the regenerator is considered to be cold. It is cooled by an external cooling circuit indicated in dark blue.
• Displacer and piston (green)
o The piston is build out of two parts. The top part contains two hollow compartments. The function of the upper compartment is to minimize the heat transport by conduction through the piston. The lower compart is for the regenerator. The top part has two different diameters. The upper part has a slightly smaller diameter than the lower part such that separation between the cylinder and the top part of the piston is large enough for the working fluid to flow from the regenerator to the hot compartment. The lower part of the piston and the cylinder have such a tight clearance that it prevents the working fluid from flowing along the piston in this section. The bottom part of the piston is connected to the top part by a flexible connection such that it does not transfer transversal forces. The bottom is connected to the shaft in order to extract work from the system.
• Sealings are located at several placed to keep the working fluid in place.
o Sliding seals: Just below regenerator. This seal is exposed to the highest temperature, as the working fluids exiting the regenerator in an upwards stroke is not necessarily cooled down fully by the regenerator.
o Standard seals are installed between the different parts that form the cylinder. All these sealings are exposed to moderate temperatures only.
The proposed design allows for flexibility, which is desirable at this stage of the project, where only limited time was available for testing engine concepts. The internal heating circuit can be bypassed by using different connection ports from the cylinder. The top of the cylinder can be connected to the bottom port and the ports near the connection between the two piston parts. This allows for the use of an external heating circuit in case the internal heating system is limiting the heat input. In this case the internal regenerator is replaced by a solid block preventing the flow through the piston and thereby forcing it through the external circuit.

ENGINE STRENGTH CALCULATIONS: Since the Up-THERM engine will be subject to high temperatures and pressures adequate strength calculations are required. Besides the calculated maximum allowable pressure for given temperatures also the details of the strength calculations are presented in the related Deliverable.
As the engine cylinder is the only designed part exposed to internal pressure of the working fluid, this part will be subject of the strength calculations. Although the regenerator and the heat exchangers are also exposed to the same internal pressure, no detailed strength calculation is required for these parts. The use of standard tubing which are rated for pressures above the maximum working pressure makes these calculations redundant. The design assessment was performed according to the Pressure Equipment Directive (PED) 97/23/EG.
The maximum allowable pressure in the UpTHERM engine is 100 bar (10 MPa) when the maximum temperature is 400°C.
The Up-THERM engine cylinder is classified for Risk Category SEP (Sound Engineering Practice). The volume of the cylinder amounts 0.35 liters. The associated maximum operating pressure at these volumes is equal to 200 barg. Equipment classified according to the charts in Annex B as ‘SEP’ will be required simply to be designed and manufactured according to ‘sound engineering practice’. SEP equipment will need to be accompanied by adequate instructions for use and must bear markings to permit identification of the manufacturer or authorized representative established within the Community. CE marking must not be affixed to SEP equipment.
The results of the Finite Element Analysis are shown below (the distribution of the equivalent stress, i.e. a representative single valued stress for a multi-dimensional stress). The global extreme values of the maximum and minimum principal stresses as well as equivalent stresses are provided; a linear static calculation is used the stresses for both load cases are the same. However, the deformations are somewhat different due to the different elasticity moduli.
The above calculations provide the stresses inside the engine cylinder. To determine if these stresses are not too high the maximum equivalent stress is compared to the maximum allowable stress. This ratio or safety factor should be well above unity, which is the case at both temperatures.

PRODUCTION DRAWINGS: The executive drawings of the engine are presented in the related deliverable submitted in P2. An overview of the engine is provided, where all different parts are labeled. The complete system overview including also the load circuit and the heater is also presented.
Encontech B.V. proposed a number of new engine concepts [Glushenkov M, Kronberg A. Heat to mechanical energy converter. PCT/EP2012/064094, 18.07.2012. International Publication Number WO 2014/012586 A1]. From these concepts, as first step, the simplest one, which corresponds to the engine described in the project proposal (and which does not differ cardinally from the available engines) was selected. The main reason was to have a simple engine that would permit to study the basic engine processes and performance. One of the advantages of the engine is that different regenerators can be accommodated in the engine. An important advantage of the selected concept is that it resolves the problem of engine sealing and piston wear which is common for Stirling type engines.
The sliding valve and the executive design of the Up-THERM engine are shown in the Deliverables. Finally, an engine manual was produced in D5.5 showing the main functionalities and operation instructions of the system.

-------- Design and implementation of the final prototype -----
The main result of the work carried out under WP6 by the RTD performer LABOR is the creation of a simplified layout for the micro-CHP which can be used in a real, domestic application. From the left in the scheme prepared for the project we have represented a boiler, which is used to feed heat to the engine in agreement with the definition of cogeneration. Then with flue gas we can recovery the waste heat and use it to cover the heating demand. Here to feed heat to the engine we use an intermediate heat exchange between primary heat source and the engine hot part. This intermediate heat exchange is made by a thermal oil circuit. This configuration allows to use different kinds of heat sources (as said before for future application we can use biomass, or solar concentrator). The rest of the boiler seems like a normal domestic boiler. In the middle of the figure is represented the engine, here the cooler is fed with water from the domestic heating circuit. It is placed between the output of heating circuit and the input of the boiler.
The complete layout used for the Up-THERM experimental set up is also reported in the output documents generated in this WP.
This represents the final stage of the experimental setup, but it comes through 3 different steps:
1. First preliminary step: Only boiler before modifications and unit heater are mounted. In this way we can adjust the boiler to work with gas propane acting on gas valve.
2. Second step: Layout is like the final layout presented before, without the engine. Here we intend to investigate the behaviour of the boiler modified using the two plate heat exchanger to simulate the behaviour of an engine that absorbs and releases heat.
3. Final step: The final layout is used to evaluate how the engine exchanges with the rest of the circuit and to measure the response of the engine in terms of energy generated.

As widely described in D6.1 the intention of the partners was that of separating the description of the plant components depending on the circuits they belong to. This allows to make a structural and functional differentiation of the components used for the Up-THERM experimental setup.
The plant boiler has the main function of providing the primary heat source to the whole cogeneration system. This role might be undertaken by several devices making use of very different technologies and structural classification. For the project purposes, we opted for the use of a heat source that might own the complete set of features listed below:
1. Widely diffused at a commercial level,
2. Ease of use,
3. Safety during use,
4. Low cost,
5. Use of different gases, and ease of finding and storing them,
6. Easily modifiable
All these requirements led us to the selection of a domestic gas boiler; specifically, among the several different types of boiles on the market, we have selected those that could be more easily modified and adapted for the Up-THERM purposes. Among them, in addition, we decided to use a condensing boiler to respect one of the initial project requirements.
We therefore decided to opt for boilers holding simpler configurations, higher performance in terms of efficiency and lower emissions; the selected boiler was a unit from Immergas EOLO EXTRA 24kW HP. We must then specify that the boiler was adapted to be fed by propane instead of methane, as we did not have the possibility to connect it to the distribution lines in our premises.

The external exchanger for the water circuit is a unit heater. The coil is manufactured from steel tube. The fins are pressed from aluminium sheet, bonded onto the tubes. The fan and motor assembly is made up of three components: the fan, the motor and the safety guard, which also acts as the main support. The standard motor fitted is a hermetically sealed motor which is maintenance free. The motors are supplied as standard for a three phase 230/400V 50Hz supply, with 4/6 pole two speed (protection IP55).

This part of the plant represents the core of the heat adduction system for the engine developed by the partner UT in the project. Our decision to make use of diathermic oil was proposed by the RTDs from the University of Twente, as the methods used in their past experimental trials for heating the external cylinder of the engine were not satisfactory, and not easily adjustable. The use of an exchanger making the heat spatial distribution and the heating time continuity homogeneous on the surface of the cylinder was the starting point for us to develop the rest of the Up-THERM plant.

The pump has to be able to work at high temperatures and for that here is used a magnetic driven pump. The thermal oil at high temperatures never gets in touch with the mechanical parts of the pump. The coupling is due to a coaxial magnetic joint. The model of the pump is MPUMPS T MAG-M1. All the circuit is made of stainless steel AISI 316. Pipes have an external diameter of about 20 mm and a thickness of 1.5 mm. For the valves we use needle valve with insulation and seal made of graphite.

This part of the experimental setup is meant to simulate a load connected to the engine pressure plug and to measure its performance as an output. Operatively, this can substitute the system of conversion of hydraulic pressure into electric energy, as shown in the operative layout of the Up-THERM plant.

As mentioned in the previous project documents, this exchanger is part of the engine. In order to reduce the heat transfer resistance the exchanger was welded around the hot cylinder of the engine. It is composed by 9 longitudinal fins that are made of stainless steel 316 as the cylinder. The fins have a double role, to guide the thermal oil flow up, down and around the cylinder, and to increase the heating surface. Then the cylinder and the fins are enclosed in a tubular jacket that is welded only on the cylinder in order to reduce the dispersion of heat between jacket and fins. This jacket is made of steel 316.

------ CHP Testing ---------
According to the workplan, approximately 1 month (M25) of the project was used by LABOR to pre-test all the components mounted on the final CHP prototype, assembled at the RTD premises in Rome. During this phase, important sessions of tests were carried out on the plant to verify its proper functioning without the inclusion of the Up-THERM engine. This activity was conducted in 2 phases:
o The first step foresees the presence of the boiler before its modification for the final test, and the inclusion of the heating unit used only to release the generated heat;
o The second part of the tests was performed using the gas boiler modified with the integration of the thermal oil circuit, still without the integration of the engine; this allowed us to pre-test the overall system and to eventually solve technical problems before the inclusion of the Up-THERM engine for the final phase of the tests.
Both parts of the tests confirmed that the overall system works under the mechanical, hydraulic and electronics point of view. The control system was also checked to verify that data acquisition runs smoothly, that measurements are duly performed and that proper control of the whole process is carried out. The UI has been assessed to work fully, as expected, this completing the start-up and verification task under WP7.
The third step of the tests plan foresees the tests with the engine to verify how it is capable to exchange heat with the rest of the system and to measure its response, assessing the final performance against requirements. Several days of tests were performed, but we are presenting only data related to the final phase in order to more easily summarize the information coming from relevant sessions. LABOR has in fact performed the first 2 steps of the tests as from the scheme above in order to assess the performance of the overall system without the engine, to be sure that its functioning could be properly investigated and to avoid any false result coming from a potentially underperforming surrounding environment, which however proved appropriate and duly performing.
This activity involved all the partners who promptly supported the tests phase and gave active contribution on how to possibly solve some of the technical difficulties managed during this stage. The final results of the tests allowed the partners to make specific considerations on the novel technology represented by the Up-THERM engine, which are reported in D7.1.
As already mentioned in D6.1 for the final test phase we used a specific experimental layout, reported in the figures of our previous reports. The valves represented in the layout are used to calibrate the heat exchange before and during the tests. For the final phase where the engine is coupled with the rest of the circuit we use the V1 and V2 to exclude the heat exchanger SP1 from the overall process.

As said before, the first phase is used to calibrate the gas valve of the boiler. To do this we used the digital manometer “TESTO mod.510”. With the use of this instrument measuring the pressure before and after the gas valve we were able to convert the burner for the use of propane and we could calibrate this at about 20 kW with a mass flow rate of about 1,6 kg/h of propane using the data from datasheet.
Then in the second phase we tested the boiler modified and the thermal oil circuit. During these tests we set control parameters in order to have a stable behaviour of the overall system. After some cycles of tests a good agreement between this parameter and the functionality of the system is reached.
Before the final phase of test the engine is tested in order to avoid any problems related to the sealing of the water. For this reason, this was filled with helium up to 60 bar. After the replacement of three o-ring the engine showed a good seal and it was mounted on the test bench. Here it was filled with water from the valve placed near the high pressure accumulator, which is discharger at this stage.
In order to fill the circuit and the engine and remove the air inside it we fed the water from the valve and a constant flow was extracted from the head of the engine. After some minutes we stopped to feed water and closed the circuit. Then we charged the accumulator with an external tank of helium at a pressure of about 35 bar. The engine heater is flanged with the rest of the thermal oil circuit that is filled with the working fluid and the same is for the cooler with the water circuit of the boiler. After the purge of the air from these two circuits the system was ready for the tests.

A complete set of graph is provided to give an overview of the parameters and behaviour of the system. The first graph from the left shows the trade of the temperatures of thermal oil. From this graph we can see that for this test in a first moment a discontinuous behaviour of the system must be forced in order to investigate its flexibility and reactivity.
In the range from 0 to about 1300 s it is possible to see a very good reactivity of the of the system that is able to change the temperature of thermal oil in a reasonable time without overheating, experienced in other tests before this.
Another problem can be represented by unexpected burner’s turning off. To avoid this, in the range between 400 and 700 s we performed a test of this condition. Here when the thermal oil is at high temperature we turn off the burner for about 300 seconds. This is clearly visible from the graph that represents the heating power, where power goes almost to zero. After this period of inactivity the burner is turned on and the thermal oil increases its temperature still to the maximum value observed that is about 339°C. Finally, thermal oil is maintained at this condition for about 1 minute (the second peak in the graph).
After this test that investigated the dynamic behaviour, a long period of activity is forced, during which the operative conditions are maintained stable. The range of time considered is between 1500 and 2300 seconds. In this period we can consider the components working in steady state condition. The outlet temperature from SOD exchanger is maintained at about 307°C, while at the inlet the temp. is 271°C with a total heat exchanged of about 9000W.
Then, after this period of stable operative conditions to test the safety controls implemented in the software we force the shut down of the system. At the time 2357 s the thermal oil is forced to exceed the maximum operative temperature that we set at 340°C. After this the shutdown process starts and rapidly brings down the temperature to the value named “temp_pump_off” set in the control system.
About the graph to the right that shows the heating power, we can note that the power generated by the SOD exchanger is mostly released by the exchanger SP2, while the heat exchanged by the heater of the engine is only a little part. Now if we look at the parameters related to the engine cooler are reported, it is possible to notice that a very small amount of heat here is discharged. This reasonably means that the 2 kW exchanged from the gauges TS1 and TS2 (here labelled as Q_SP1) are basically due to heat dispersions.
The effect of a heat dispersion is also due to the high heating resistance inside the heater where probably the water does not evaporate as expected. Another graph where it is possible to see this dispersion of heat.
Here the total heat flux generated by the boiler
, and the heat released by the unit heater
are reported. In the range considered between 1500 and 2300 seconds the exchangers works in steady state condition and for this reason these two amounts of heat flux should be equal. Instead there is a difference that represents the heating dispersion, this effect being quantified and represented in one of the figures. In this figure there is also a comparison between the difference of the two heats explained before and the heating flux measured for the engine heater, here represented as
. The comparison shows a good agreement between these heating fluxes and confirms the effect of the dispersions.
From this consideration we cannot expect a good behaviour of the engine measured by PS1,2 and FLM3. For this test the counterpressure given by the accumulator ACC is regulated during the test from the 35 bar to 3 bar. The graph shows a stable pressure for all the pressure levels both for PS1 and PS2, while we expect an oscillating behaviour as indicated by the study conducted previously in the project from our RTD partners.
Of course at the same time no flow rate is registered and the values reported in the graph are due only to the mechanical vibration. This noise can be avoided introducing a dumper that can absorb vibrations introduced by pump P1 mounted not so far from the flowmeter. But we should note that the noise introduced by the vibration has a peak of about 0.11 l/min, while we expect a flow rate with a peak of about 2.6 l/min if we consider a frequency for the stroke of the engine of 1 Hz.

The tests conducted on the prototype confirmed that the engine heater demonstrates high flexibility during its use, reaching most of the expected results in terms of quantity and quality of the heat transferred.
The system is capable to feed, in a continuous mode, around 9.000W at a temperature of approximately 307°C. These values must be compared with the data coming from the model initially developed during the design phase. We report here the results of this comparison.
The final tests carried out on the micro-CHP plant of the project, as reported in this document, show the occurrence of technical problems on the engine, that did not provide the expected results in terms of performance and efficiency. This led to difficulties in coupling the engine heater - for heat adduction, and the engine cooler – meant for its recovery, to the engine to verify its functioning conditions.
As anticipated in our partners’ experimental tests report (D5.5 – Engine Manual), the complete procedure to degas the motor and to fill it with water was accurately followed before starting any kind of test on it. In addition, specific machining of the engine was necessary during the plant implementation phase to feed it with suitable heating to induce its start-up; this extra-effort was widely discussed in D6.1 where a workshop activity was described to show mechanical adjustments which were needed to establish proper heating conditions over the engine top.
Pressure and temperature conditions were always kept in the range suggested by the RTD partner UT who developed the core of the plant, the engine itself, and according to the experimental trials performed during WP5; despite this, its start-up and functioning could not be revealed by the acquisition system and neither vibrations nor responses in terms of pressure oscillating behavior could be assessed.
From the tests performed, a scarce performance of the engine in absorbing and releasing heat was assessed. As suggested by our partners in the course of their studies on the engine, some adjustments to the system might be taken into account in the future after the end of the project – see Final PUDK and the plan for a post-project research phase - to improve the engine geometry and fully demonstrate its value during operation. Some key suggestions are summarized below (please also refer to D5.5 for further detail):
- Replace water with other working fluid and determine optimal operating conditions. These conditions include: temperatures of the heater and cooler, amount of working fluid in the engine (or initial pressure).
- Determine optimal cycle which depends on the engine load (e.g. hydraulic circuit with accumulators or hydraulic cylinder with a crank gear).
- Develop a heater corresponding to the heat source and the engine operating parameters.
- To develop a regenerator corresponding to the engine cycle.
- If water is replaced with other working fluid with higher compressibility the dead volume of the cold space should be reduced.
However, despite the technical and experimental difficulties that were overcome in the course of the final phase of the project to test the plant, and despite the overall engine performance initially verified during WP5 must be confirmed (efficiency ~7% and mechanical output in the range 20-30 W), we can state that the work done on the plant gave several positive returns.
As a conclusive remark, we can in fact state that the project has led to promising results as it allowed to deeply investigate a field which is only partially or insufficiently treated in other research projects. The Up-THERM research has given the Consortium the possibility to acquire data, information, theoretical and practical knowledge which proves useful for the development of a micro-CHP system potentially taking advantage of non-fossil energy sources (biomass, solar concentrators, etc.). An environmentally friendly working fluid was also selected for the project – i.e water – and the whole system was fuelled by propane, as mentioned in our past reports.
As a result of the tests carried out from M24 to M26 of the project, we can surely state they highlighted limits but also strengths of the technology, to be taken into account for the future developments on the system, planned by the partners after the end of the research project. Additionally, the development of a small-scale boiler equipped with an integrated circuit working with diathermic oil proves to be a good result from a technical point of view, as there is no other documented example of such device for this power range. Finally, the experimental setup developed during the Up-THERM project lifetime has been assessed to be of interest for additional sperimentation thanks to its modularity and its potential adaptability to future versions of the engine in the power range of 0.5- 1.5 kW, thus perfectly fitting micro-cogeneration projects needs.

--------- Dissemination, exploitation and IPR management --------
DISSEMINATION ASPECTS IN UP-THERM: The Final PUDK, which reassumes the main outcomes of the activities performed by the partners in the course of the project, contains the following information:
o Dissemination of Knowledge. An overview of the stakeholders’ groups for the project was presented, meaning the “groups or individual that can affect or can be affected by the achievements of the project”; the dissemination strategy adopted in the project and its goals was detailed, including the type of message to be spread and the possible tools supporting the diffusion of the message; finally, the dissemination plan and work, which shows the roles and activities that each partner carried out for a complete and widespread diffusion of the news related to the project was included in this part of the document.
o Exploitation strategy. This part of the PUDK Deliverable includes a market overview demonstrating the real necessity for new technologies such the one proposed in the project; the concrete exploitation strategy and plan adopted by the SMEs (revised and made definitive in this final version), and the investigation of which exploitable knowledge has been generated during the course of the project that can be used by the owners to their best advantage; The IPR Management approach is detailed in this section, and A revised business plan respect to the one drafted in the DoW is presented, which includes all the steps that the Consortium sees as necessary for reaching a final commercializable product.
o Training activity. This part of the document shows how the transfer of knowledge from the RTDs to the SMEs was managed in the project and what methods were proposed for training the companies on the Up-THERM plant functioning.
STAKEHOLDERS: Equally crucial to having the dissemination message defined and agreed is having clear to whom we want to disseminate the results of the project. Our intention is in fact that of reaching a considerable number of individuals or companies who can be interested in the innovation proposed in Up-THERM.
To this end, a stakeholders analysis was performed. A stakeholder is any person or organization, who can be positively or negatively impacted by, or cause an impact on the actions of a company, government, or organization. Types of stakeholders are:
• Primary stakeholders: are those ultimately affected, either positively or negatively, by an organization's actions;
• Secondary stakeholders: are the ‘intermediaries’, that is, persons or organizations who are indirectly affected by an organization's actions;
• Key stakeholders: (who can also belong to the first 2 groups) have significant influence upon or importance within an organization.
In Up-THERM, the main categories addressed by the dissemination action of the Consortium will be the primary stakeholders and the key ones, when they do not coincide. This is mainly due to the fact that the project aims at developing a micro-CHP (Electrical Power < 3 kW) able to exploit low temperature feedstock with high efficiency (25% at least in case of natural gas fuelled engine) and low cost (cost target = 650 - 1000 €/kW), thus communication will represent a tool by which the approach with the market will be favoured.
In the case of Up-THERM, we can summarize this group of companies as follows:
KEY AUDIENCE - In this category we will include public & private energy efficiency promoting organizations
The public and private organizations which promote the energy efficiency technology solutions should show interest on an innovative technology able to promote the application of CHP technology in small power size applications, mainly in the domestic sector. Presently, cogeneration units have a wide diffusion for medium and large applications (Power > 200 kW), while in the domestic, small offices, small commercial sectors the low conversion efficiency and the high costs are stopping the CHP technology installations. Developing competitive solutions to improve the small size CHP efficiency and to reduce its cost perfectly fit the energy efficiency context.
PRIMARY AUDIENCE - The primary audience for the Up-THERM dissemination will be mostly constituted by:
1- Companies in distributed electricity production;
2- Energy efficiency companies, Energy Service Companies (ESCo);
3- CHP manufacturers;
4- CHP installers;
5- Municipalities;
6- End-users as markets, offices, sport centres, hotels, etc.

As aforementioned, the energy efficiency associations are surely a key audience to be contacted in order to disseminate the Up-THERM project results. The interest on energy efficiency technology is continuously rising in the last years for a series of crucial reasons:
1- the increasing cost of energy;
2- the growing feeling of pollutions problems due to an excessive use of fossil fuel (pollutants and GreenHouse Gases emissions);
3- The perception of risks in fuel availability, for political problems and for the absence of new oilfield discovery.
In the first part of the project, the Up-THERM Participants identified the most important Associations in the energy efficiency and cogeneration sectors to be contacted in order to promote the project results. The SMEs decided to contact the Associations in the second part of the project, after the regenerator will be designed (WP4) and during the engine executive design (WP5).
COMPANIES’ NETWORK: As anticipated, companies potentially interested in the Up-THERM project results are of different sectors:
1- Companies in distributed electricity production;
2- Energy efficiency companies, Energy Service Companies (ESCo);
3- CHP manufacturers;
4- CHP installers;
5- Municipalities;
6- End-users as markets, offices, sport centres, hotels, etc..
It is clear that a specific message should be formulated for companies of each sector. This is a target for the second part of the project, when the Up-THERM concept will be clearly demonstrated and quantitatively assessed. In the first part, each SME Participants contacted some specific companies among their Customers and Suppliers, to advise them of the project start-up and of the research targets.
To do this, the SME Participants and RTD Performers took advantage of the participation at congresses and fairs to disseminate among the energy efficiency and CHP operators the Up-THERM message, and additionally published and created ad hoc scientific materials supporting the diffusion of the project results among such a specialized and professional group of players in the CHP sector.

EXPLOITATION ASPECTS IN UP-THERM: Following internal discussions held within the Consortium in the second period of the project on the basis of the most recent results on the prototype and on the commercial interests of the beneficiaries, the SMEs have decided to validate and confirm the exploitation strategy outlined in the Description of Work, substantially validating and confirming the approach. However, additional efforts will be necessary to further improve the performance of the system and obtain a more mature technology that can be then exploited commercially. Specifically:
• ECT will be the owner of the engine design. The project started from the ECT innovation on the engine and the rights to this background, as reported in the Consortium Agreement, is free of charge during the project. The possibility to apply a licensing fee will be discussed at the of the project, if needed. ECT will be exclusive engine producer for the CHP plant, to be commercialized with TEP and EFICEN.
• TEP and EFICEN will have the exclusive right to install Up-THERM natural gas fuelled CHP units. They will divide the European market (TEP in Italy, Germany, France and East Europe, EFICEN in Spain, Portugal and Northern Europe). The two SMEs will approach the extra-European market together, by signing a commercial agreement.
• NE will share the ownership of solar energy driven Up-THERM system with ECT (80% NE – 20% ECT) and will have the exclusive right to install Up-THERM solar driven CHP units in Europe.
The following agreements, to be signed after the end of the project, will be subject to the technology validation and on the positive assessment of its performance:
o TEP – EFICEN for market division;
o TEP – EFICEN for joint commercial exploitation in the extra-European countries;
o TEP – EFICEN – ECT for the CHP units supply;
o NE – ECT for solar driven CHP unit production and commercialization.

According to the initial strategy outlined in the DoW, the first applications to be developed will be the solar energy driven and the natural gas driven one. This because two markets had been identified as possible for the Up-THERM CHP plant, the one for domestic applications and the one related to solar energy systems.
However, as detailed in the next sections, the solar driven application is still under evaluation on behalf of the Consortium, and an accurate analysis of the modifications to be done to the plant for such a scenario was post-poned by the partners to a second round of activities (named “post-project phase” in this document). The main application scenario for the technology developed during the 26 months was then maintained as the one for domestic/residential buildings.

ROADMAP FOR THE COMMERCIALIZATION OF THE UP-THERM SYSTEM: From the analysis carried out on the state of development (intended at M26), we can state that the main output of our research project is represented by the Up-THERM CHP plant – holding prototypal character - that is now properly working and capable of producing an electrical output. In this sense, even if ambitious, the scientific and technological objectives of the research are to be considered as achieved.
However, results on the engine efficiency and on the overall unit capacity in terms of power still need to be improved; this in the view of obtaining a more attractive and mature technology, ready to work in a real environment.

For this reason, the SMEs – supported by their partner RTDs – have decided to draft a POST-PROJECT PLAN, which describes, at a very high level, the work to be done after the end of the project to reach more desirable results in terms of output power capacity.

BUSINESS PLAN FOR THE BENEFICIARIES - As anticipated in the previous sections, the outcomes of the project will need to be further validated and improved with the final purpose of delivering a technology which is mature enough to be introduced in the micro-CHP market for the residential application (see roadmap outlined in this document planned to reach such a result).
What is available at the moment we write is therefore a tentative revision of the initial business plan included in the Description of Work taking into account such an intermediate research step. We are describing, in this paragraph, the expected benefits that the Up-THERM solution will bring to each single SME of the Consortium. Some key assumptions were included in the Final PUDK to comment the financial figures reported in the document.

1 In the financial plan we will take into account only the short-term objectives, meaning the ones set for the period 2017 – 2020, i.e. the moment in which the CHP system will be ready for the market according to the post-project plan drafted in this Final PUDK.
2 The 4 SMEs of the Consortium will produce and sell the final system and related services according to their consolidated business model.
3 The following plan is set among the partners:
• 33% of the produced systems will be used by TEP for their ESCO activity;
• 33% of the produced systems will be used by EFICEN for their ESCO activity;
• The remaining 33% will generate revenues from direct selling by NE;
• ECT will produce the 100% of the engines needed for the CHP plant sold or installed by the partners.
4 The ESCO model will be applied by TEP and EFICEN in different geographical areas, divided for the two companies on the base of their existing, consolidated network.
5 The expected price for the final product is approximately 3.600€. Revenues generated by the energy savings with the system are estimated as ranging between 500-650€ per year for the companies using the ESCO business model.
6 Total revenues for the whole Up-THERM new business is calculated as the sum of the single SMEs’ revenues for the year.
7 A realistic short-therm sales objective has been set to slightly more than 1.100 units in the years 2017- 2020, according to the numbers and figures drafted in the PUDK in relation to the micro-CHP market in the EU-27 (market share of 1,15% in 2020).

The business plan figures are attached to this report (see attachment).

TRAINING: The Up-THERM SME Participants are well aware of the necessity to receive materials and information regarding the functioning, operation and maintenance of the CHP unit developed in the course of the project from the research performers. Thus, a specific task (T8.3) is devoted to the know-how transfer, since the technology transfer from the research centres to the final beneficiaries – the SMEs – is a crucial aspect of the project. For what concerns the training materials, the RTDs in the Consortium decided to implement a presentation to be shared with the SMEs to transfer them all the knowledge on the engine and on the final developed CHP plant regarding its functioning, operation and maintenance aspects. An overview of the presentation was included in D8.5 where further details about this activity have been provided.
Should there be any necessity, on behalf of the SMEs, to receive assistance or to know more about the plant after the end of the project, the following plan was agreed: 1) the RTDs will provide assistance via email, phone, or web in case of malfunctions or requests for additional information up to 1 year after the official end of the project; 2) despite the plant start-up or operation prove extremely simple and accessible to technical personnel and the user interface is immediate, a user manual could be created in case of need by the SMEs to have the full set of instructions laid down in written.

Potential Impact:
The purpose of Up-THERM project is to create business opportunities for the SMEs proposers involved.
The development of an innovative heat engine, characterized by high efficiency even at low power (< 3 kW) and by low cost (200 – 500 €/kW, vs. 3500 €/kW of Stirling engine) thanks to its simplicity and to the use of a dense working fluid, would boost the SMEs competitiveness in their own markets. Specifically:
o TEP Energy Solution is an Energy Service Company (ESCo), always looking for competitive and efficient technologies to be proposed for Third Party Financing (TPF). The application of Up-THERM engine in micro-CHP systems could constitute a business opportunity, perfectly fit with the SME need since it would assure a quick Return of the Investment;
o ENCONTECH BV is a Dutch engineering company, expert in engine design and development. It is the initiator of the Up-THERM technical idea together with University of Twente and it is looking for partners to further develop the Up-THERM engine up to a CHP prototype. The exploitation of Up- THERM technology would allow to develop a competitive product with many potential applications, promoting the company in the European market;
o NOON ENERGY is a Spanish small company developing an innovative Stirling engine specifically designed and optimized to run on concentrated sunlight. Currently, the Stirling engine is suspended in the mirror’s focal point and converts the intense heat into clean electricity. Developing an innovative heat engine, with a cost much lower than Stirling, will make more cost-competitive the NE technology, opening a more extended market;
o EFICEN RESEARCH is a Spanish energy efficiency technologies company. TEP and EFICEN will jointly commercialize the Up-THERM CHP system across Europe, dividing the market and proposing TPF schemes specifically formulated for each European country.

The responsible research partner for the development of this result was ICON (WP3).
ICON applied an existing, integrated molecular-based platform to the problem of the computer-aided optimisation of the Up-THERM system while taking into account explicitly the molecular design of the working fluid. The platform is based on a combination of fundamental thermodynamic modelling and advanced numerical solution techniques, and allows the integration of models across different scales so that molecular-level models of working fluid properties can be used at the system scale. ICON also identified a series of optimal working fluids, or working fluid mixtures, for the Up-THERM heat engine, which maximise performance across a range of operational conditions (e.g. temperature availability to the device). In this case, optimal performance is defined by a high efficiency, a high power output, a low cost and a low environmental and safety impact.
The second exploitable result of the Up-THERM project is the design of the innovative high efficiency and low cost engine, based on the ECT concept. The executive design production was fulfilled during the activities of WP2 – Engine modelling (performed by ICON), WP4 – Regenerator design (UT) and WP5 – Engine Executive design (UT).
ECT proposed a number of new engine concepts. From these concepts, the simplest one, which corresponds to the engine described in the project proposal was selected. The main reason was to have a simple engine that would permit to study the basic engine processes and performance. One of the advantages of the engine is that different regenerators can be accommodated in the engine. An important advantage of the selected concept is that it resolves the problem of engine sealing and piston wear which is common for Stirling type engines.

The last result is the final prototype of Up-THERM CHP, which was fabricated during WP6 and tested in WP7 at LABOR’s facilities in Rome. The plant includes not only the Up-THERM engine developed by UT but also a set of valves, heat exchangers, pipings, sensors and general components allowing to verify the functioning of the engine and providing it the necessary amount of heat. Photos and details on the plant were included in D6.1 (CHP executive design) and in D6.2 (concerning the control system developed to drive the overall process). The prototype fabrication was planned to be performed between M19-M22 and its testing carried out from M20 to the end of the project (M26). As detailed in the Deliverables related to the plant, the system was implemented using 2 different layouts: one without the engine (to test the functioning of the surrounding components) and one including the engine (to verify the efficiency of the Up-THERM core technology in generating output power in the range required by the domestic application, i.e. 1-3kW).

Target market of Up-THERM project is the micro CHP (< 50 kWel), which is considered to be a “disruptive technology” having a potential capacity of similar order of magnitude to the existing nuclear generating capacity in the emerging liberalized European energy markets. Micro-CHP is expected to provide an overall installed generating capacity exceeding 60 GWel in EU15. Following such market potential and considering an average installed cost of 1500 - 2000 €/kW, the overall market potential for micro-CHP can be estimated to range in 90-120 billions of Euro.
As Up-THERM technology soundness will be demonstrated thanks to the 3 kW micro-CHP prototype testing on field, TEP, ECT and EFICEN will organize the production of the micro-CHP units, fed by natural gas, to be installed by TEP Energy Solution and EFICEN. The two ESCos will divide the European market but they jointly propose the solution with a horizontal partnership strategy.
At the same time, NE and ECT will scale-up the Up-THERM prototype and demonstrate the feasibility and reliability of solar driven 12 kWel CHP system, opening a new market.
Following internal discussions held within the Consortium in the 2nd period of the project on the basis of the most recent results on the prototype and on the commercial interests of the beneficiaries, the SMEs have decided to validate and confirm the exploitation strategy outlined in the Description of Work, substantially validating and confirming the approach.
• ECT will be the owner of the engine design. The project started from the ECT innovation on the engine and the rights to this background, as reported in the Consortium Agreement, is free of charge during the project. The possibility to apply a licensing fee will be discussed at the of the project, if needed. ECT will be exclusive engine producer for the CHP plant, to be commercialized with TEP and EFICEN.
• TEP and EFICEN will have the exclusive right to install Up-THERM natural gas fuelled CHP units. They will divide the European market (TEP in Italy, Germany, France and East Europe, EFICEN in Spain, Portugal and Northern Europe). The two SMEs will approach the extra-European market together, by signing a commercial agreement.
• NE will share the ownership of solar energy driven Up-THERM system with ECT (80% NE – 20% ECT) and will have the exclusive right to install Up-THERM solar driven CHP units in Europe.
The following agreements, to be signed after the end of the project, will be subject to the technology validation and on the positive assessment of its performance:
o TEP – EFICEN for market division;
o TEP – EFICEN for joint commercial exploitation in the extra-European countries;
o TEP – EFICEN – ECT for the CHP units supply;
o NE – ECT for solar driven CHP unit production and commercialization.
According to the initial strategy outlined in the DoW, the first applications to be developed will be the solar energy driven and the natural gas driven one. This because two markets had been identified as possible for the Up-THERM CHP plant, the one for domestic applications and the one related to solar energy systems.
However, the solar driven application is still under evaluation on behalf of the Consortium, and an accurate analysis of the modifications to be done to the plant for such a scenario was post-poned by the partners to a second round of activities (named “post-project phase” in the PUDK Deliverable). The main application scenario for the technology developed during the 26 months was then maintained as the one for domestic/residential buildings.

List of Websites:
The implementation of a public project website has been foreseen in Up-THERM project with the purpose of raising awareness of its technological content and of the innovative solution proposed in it.
The project web site is one of the most versatile dissemination tools. It is meant to inform stakeholders (and others) about the project, findings to date, resources that have been created and upcoming events/activities related to the sector. As a dissemination vehicle, it also include the publicity that the project has generated, journal articles, press releases and presentations at conferences led by the project partners with the intention of spreading the interest in the Up-THERM technology.
For its intrinsic features, the Up-THERM website is one of the most important assets for the dissemination of the project. During the design and test phase of the website one of the goal has been the definition of the key message to be communicated through the site and the way to communicate it. Particular attention was paid to the “receivers” (the end users), especially to what they need to know about the project and how the message should be communicated. The project website can be found at the following link:
Starting from the comments received in the 1st assessment report at M9, the Consortium has modified the website and added updates to the information reported in it in the course of the Second Reporting Period. In particular, major changes related to:
1. Modification of the public website address: the contents and the structure of the website were shifted to the more visible link: This was possible through the purchase of the new domain and its upgrade, that granted the possibility to have access to additional services among which the activation of a statistical analysis on the visits to the webpage.
2. Updates to the website pages contents: following the request of updating the materials and the contents included on the website, and following the withdrawal of ALENCO from the project, the partners have agreed to correct, update and improve this communication tool in the course of Period 2. The following changes have been made:
o Home Page layout improved,
o News Page updated with all the General and Technical meetings held during the project with their dates and venues,
o News Page updated including events where the Up-THERM project was disseminated,
o Consortium page corrected (participation of ALENCO removed from the text),
o Redirect to the LinkedIn showcase included in the Home,
o Downloads page updated with the relevant dissemination materials created in P2 (brochure, press releases, poster),
o Private area updated with all the Deliverables produced in the project, the meeting minutes, the scientific publications and any other confidential information on the technical aspects of the project (executive designs, system layout, etc.).
The Project Coordinator contacts are hereby reported for any enquiry or information on the project.
Eng. Caterina Dentoni Litta (TEP Energy Solution) – Email:
Phone: +39 06 64824058

Project information

Grant agreement ID: 605826


Closed project

  • Start date

    1 September 2013

  • End date

    31 October 2015

Funded under:


  • Overall budget:

    € 1 481 256,18

  • EU contribution

    € 1 081 641,40

Coordinated by: