Building sector accounts for more than 60% of total energy consumption in the world, while the share of domestic buildings is about 20-40%. The energy consumed is mostly utilised for heating, cooling and ventilation purposes, contributing massively to fossil fuels consumption and thus CO2 emissions. Combined heat and power (CHP) systems generate electricity and harness the heat by-product for heating of buildings. Currently CHP systems deliver a combined efficiency of up to 80%, residential and small business bills can be reduced by 20-40%, and carbon production can be reduced by 30%. They also offer fuel flexibility, and being an independent system, reduce demand on centralised power supply and distribution systems. The current roadmap for UK CHP implementation will, by 2030, yield primary energy savings of 85-86TWh/a with a savings of 10-14Mt/a. The mCHP market is currently served by Stirling, ICE, and ORC systems, all of which have significant issues that limit wide mCHP installations. The proposed ECHP system will lead to significant energy savings (greater than 40%), CO2 emissions reduction and will be approximately 30% more efficient than current mCHP systems due to unique geometry and control system applied to the highly efficient Ericsson cycle. The ECHP will use Helium, eliminating the need for HFCs. Being an external heat engine allows the use of a variety of fuels from gas, petrol, diesel, biogas, biomass, etc. The small size and silent, vibration free operation allows renovating existing building stock where the system could be installed in constrained boiler spaces. If successful, the entirely new class of mCHP will be ideally suited for new and existing UK buildings and have: (a) high efficiency; (b) low maintenance; (c) silent and low vibration; (d) HFC free; (e) compact design; (f) implementation of a simple, consumer friendly GUI interface allowing optimal system control; and (g) use external heat source, allowing a wide variety of fuels. The proposed ECHP system is expected to have the following technical advantages: a system incorporating optimised compressor and expander geometry to approach isothermal operation, computer control of individual rotor motor-generators to optimise cycle efficiency and quicker start to operation times, system integration of combustion chamber, expander, recuperator, and compressor for maximum efficiency, and an optimized control algorithm with GUI control to create a mCHP suitable for demonstration of the theory and research development. Research will begin with description of the theoretical concept in relation to the ideal Ericsson cycle. System components will be modelled, to include various geometries. Using developed computer analysis programs and CFD, rotor design, porting, and recuperator component designs will be optimised as individual components then as an integrated system. Computer simulation models will be used to predict the thermal and electrical performance of the ECHP system. This process will perform an optimisation study of the system by taking into account the influence of different parameters of the ECHP system and power output efficiency. Changes to the parameters and components will be evaluated as required. Only when the feasibility of the system is proven, components will be fabricated and electronic control hardware/software will be developed. The components and then the complete systems will be evaluated. A lab scale 3kW ECHP will be fabricated and evaluated. The outputs of this research will validate the theoretical modelling, significantly increase the body of knowledge of external heat engines and determine the technical feasibility of the proposed concept which aims to surpass current systems efficiencies and approach Carnot efficiency.

Potential Impact:
The impact arising from the project is likely to have significant benefits in the following areas: industries, nation, researchers and their institutions. This is specifically described as below.
Government: By tackling the techno-economic barrier to mCHP systems, this project will therefore contribute significantly to the UK development of low carbon energy, and thus to meeting the UK obligations to reduce GHG emissions. Currently the growth in mCHP applications is hampered by the lack of availability of a highly efficient, low cost, HFC free systems that allow simple retrofitting into older buildings or easy integration into new buildings. The widespread application of the proposed novel system can contribute significantly to the UK Government's target for progressively reducing carbon emissions by 2050 to 20% of the 1990 level. The proposed ECHP system will lead to significant energy savings (greater than 40%) and CO2 emissions reduction and hence it will create an opportunity to use the heat otherwise wasted in power generation to provide heat for the end user and eliminate transmission losses and infrastructure costs, which in turn will increase the UK's energy independence and greatly reduce GHG emissions. This project will therefore contribute to the growth in the nations' industrial economy, accessing the UK's building and energy technology market, thus creating employment opportunities and improving its strategic role in UK economy.
Industrially: The project will create UK manufacturing opportunities for the development and production of a completely new class of mCHP system. The follow-on development of other applications of the heat engine will create very large worldwide markets for the UK.
Socially: The project will demonstrate to domestic consumers, house builders, industry and local authorities the potential for mCHP systems in the reduction of their heating and electricity costs and hence improving their standard of living. The key features, i.e., low cost, high efficiency, low maintenance, ease of production and installation, will stimulate the mCHP market, increasing the strategic role in the UK economy and, importantly, creating more employment. The work will also help more broadly in enhancing public awareness that energy savings and reduction in GHG emissions is possible if technologies are properly developed
Project consortium: The fundamental research established during the project will be progressed towards exploitation via the effective actions of the industrial and governmental organisations involved in the project, directly supported by the academic organisations. Findings and social-technical reports will be generated and fully assessed by the industry, Nottingham City Council (NCC), supporting companies (Spirax Sarco Ltd, Geo Green Power Ltd., EPS Ltd) and the UK academic institutions. These parties will contribute to the reports that will then be published to enable other interested stakeholders to understand the benefits of the approach. These reports will also be communicated through the relevant national standardisation bodies for consideration of conversion into the national legal documents. UNOTT will be the prime recipient of the project results and learning. The academic participant will benefit in terms of improved research profile and exposure to the commercialisation atmosphere. The successful implementation of the project is expected to create manufacturing opportunities for the manufacturers of heat exchangers, compressors, motors-generators and environmental engineering companies.