The proposed project aims to investigate a high-performance, low energy refrigeration system for refrigeration in general and for food transport vehicles in particular. The proposed system is based on the integration of a trans-critical CO2 mechanical driven compression cycle and a compact ejector cooling system. The system will be driven by heat rejected from the vehicle exhaust system and heat recovered from the CO2 gas in the mechanical compression cycle. The ejector evaporator replaces the ambient air in the CO2 mechanical compression cycle, by utilizing the cooling effect produced in the ejector cycle to provide sub-cooling of the high-pressure CO2 fluid below ambient temperature. This is thought to help improve the performance of the CO2 cycle. The ejector cycle is integrated in a way to enhance sub-cooling of the high pressure gas, but not to limit the overall system performance to that of the ejector cycle. The system could be operated using two working fluids i.e., CO2 for the mechanical compression cycle and an environmentally friendly working fluid e.g., water or methanol. The proposed system is efficienct, compact and requires minimal energy to operate, features which make the system particulary suitable for applications in transport vehcles. The research programme will involve:1. Thermodynamics and energy transfer analysis of the combined CO2 mechanical compressor -ejector refrigeration system2. Computer modelling for components sizing and performance analysis of the combined refrigeration system.3. Laboratory evaluation of the performance of the system components;4. Analysis of the environmental impact of application of the system.Development of the proposed system would enable refrigeration to be provided for food storage in food transport vehicle with minimum energy consumption owing to utilisation of the waste heat and improvement of the performance of the CO2 mechanical compression cycle. The improved system performance would reduce energy consumption in this sector and also reduce the impact of the global warming attributed to the use of HFC refrigerants.

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.

Air conditioning (AC) is one of the major energy systems applied globally with a market size of around £80 billion per annum. Current AC technologies require large amounts of electrical or thermal energy, accounting for 20% global electricity consumption and resulting in 1,100 mega-tons of carbon emission. The project aims to establish a scientific foundation for a pioneering, near-zero-carbon and all-climate-adaptive AC system. Compared to existing AC technologies (i.e. mechanical vapour compression, absorption, and adsorption types), the new AC system leads to over 80%-90% energy bills saving, and near-zero carbon emission. Unlike existing evaporative cooling AC systems which only suit arid climates, the new AC will be all-climate-adaptive. Novelties of the research lie in: (1) The best performing sorption, diffusion, air-tight and light-absorptive materials will be identified and/or refined; (2) A unique sorption/desorption bed comprising an air-flow-interactive sorption layer and a light-absorptive desorption layer will be developed; (3) A bespoke natural light harvesting configuration to deliver a controlled light radiation into the desorption layer surface; (4) The latest Fractal theory in the first attempt to a multi-medium/sized porous block instead of the traditional single medium/sized porous block; (5) A unique multiple-scale light simulation model, which integrate a non-sequential ray tracing method for simulating the macro-scale light and a finite-difference time-domain method for simulating the light-moisture interaction on the porous desorption surface; (6) A novel 'life-cycle-cooling-cost' oriented optimisation method. The project research programme includes: (1) Screening, refinement, characterisation and selection of the sorption/desorption materials, and determination of the composition/combination methods of the selected materials; (2) Establishment of the theoretical foundation for the light collection/transmission/distribution and light-moisture interaction and conduction of associated computer simulation modelling; (3) Establishment of the theoretical foundation and computer models for moisture adsorption, permeation, diffusion and vaporisation within the porous 'moisture-breathing' bed, and optimisation of the structure of the 'moisture-breathing' bed; (4) Optimisation of the integrated operation between the light-driven 'moisture-breathing' bed and dew point air cooler using the 'life-cycle-cooling-cost' oriented method; and investigation of the AC's building integration approach; and (5) Construction/testing of the AC prototype (including microbial hazard control) and validation/refinement of the integrated AC computer model. The proposed research will be carried out by a cross-university and multi-disciplinary team comprising Prof. Xudong Zhao of UHULL who is the world-class academic specialised in heating, cooling, renewable energy and energy efficiency, Prof. Semali Perera of Bath who is a leading scientist specialised in porous sorption/desorption materials, Prof. Barry Crittenden who is a Fellow of Royal Academy of Engineering specialising in adsorption and membranes, Dr Carmelo Herdes who is specialized in molecular simulations, experiments and characterization of sorption/desorption materials and molecular transport with industrial relevance, Prof. Brad Gilbon of UHULL who is an internationally recognised optical scientist, Prof. Jeanette Rotchell of UHULL who is a leading scientist specialised in environmental biology, Dr. Xiaoli Ma of UHULL who has expertise in renewable energy and dew point cooling, and Dr. Zishang Zhu of UHULL who is specialised in integrating renewable energy system into buildings. The project team will be supported by FIVE UK industrial/governmental organisations.