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A NOVEL TRI-GENERATION SYSTEM POWERED BY SOLAR ENERGY

Final Report Summary - ANTSPSE (A NOVEL TRI-GENERATION SYSTEM POWERED BY SOLAR ENERGY)


1) A summary description of the project objectives
The project aimed to develop a tri-generation technology that can be used to provide decentralized electricity, heating and cooling, and powered by solar energy. The trigeneration is achieved by integration of steam engine with desiccant cooling/heating technology. The desiccant cooling/heating system uses an innovative membrane technology to maximise heat and mass transfer between the air and the desiccant solution, and also eliminates the carryover issue associated with liquid desiccant systems.
The research investigated electricity output, heat and mass transfer properties through theoretical and experimental measures. A small scale prototype was designed and constructed and tested under a range of conditions.

2) A description of the work performed since the beginning of the project
The specific objectives of the project and the corresponding implementations are presented below:
• CLFR performance simulation and optimum design
The comprehensive optimization evaluation for the LFR concentrator involved the development of a geometrical optical design, optical performance simulations using ray trace technique and theoretical thermal performance assessments. The effects of various parameters on the optical and thermal efficiencies of the LFR concentrator were considered with dimensionless parametrical analysis. For a small scale LFR concentrator system with aperture half width limited to 1,100mm, the optimum optical design was determined to be a focal length of 2,200mm and the prototype and experiment of the LFR concentrator have been performed.
At same time, a novel Semi-Parabolic Linear Fresnel Reflector (SPLFR) Solar Concentrator is proposed which is formed by linear plate mirrors whose edges located at a parabolic line. The solar radiation flux distribution on the absorber pipe of evacuated pipe absorber after concentrating by SPLFR concentrator shows that the maximum flux locates symmetrically at the two edges of pipe, the centre of pipe is lower comparing with the edge flux and the radiation density distribution on the absorber vertical section is almost symmetry and the peak intensity is located at the upper surface near the pipe horizontal axis, and the uniformity of radiation distribution is stronger for the focus length 3000mm compared with that of focus length 1700mm.
• Reflector coating laboratory testing
Two kinds of glasses coated TiO2 with different thickness measured proportionally by surface electrical resistances 7Ω and 14Ω have been made and their cleaning properties been evaluated under the daylight. Their clearing efficiencies are 80.76 and 58.14 respectively.
• System performance simulation
Commercial Computerized Fluid Dynamic (CFD) modelling has been carried out to investigate the performance of LFR evacuated tubular absorber and liquid desiccant cooling. The simulation results reveal that the heating by the nonuniform radiation distribution on the absorber enhances the heat transfer from the pipe wall to the working fluid and the Nu number is higher than that of pipe flow in the lamina flow and transition regime.
A thermohydrodynamic modelling has been developed for a cascaded Organic Rankine Cycle (ORC) system with a scroll expander. The simulation results show the efficiency of two-stage ORC system is 38.9% higher than that of single stage system when R245fa is used as the working fluid and the specific work of single stage ORC system with R245fa increases linearly with the degree of superheat.
• Construction, testing and monitoring of a prototype trigeneration system
A small-scale prototype has been constructed and the experimental data included pressures, temperatures, working fluid flow rate and electric load voltage and current, cooling efficiency have been collected to investigate the performance of trigeneration system. The expected results have been obtained.
• Economic and environmental benefits
The potential economic and environmental benefits of the proposed trigeneration system have been analysed. The payback period of the solar energy system has been estimated for some selected locations.
• Dissemination and exploitation
The novel design concept of the multifunctional solar trigeneration system based on use of
ORC has been presented at several conferences and seminars. The research activities of this
project have also generated a number of research articles. A patent application has been prepared to protect the technological concept and details of the structure design.

3) A description of the main results achieved so far
The main results achieved so far are listed as follows and also shown in the attached document of figures:
• Ray-tracing and thermal performance simulation of the LFR has been carried out to optimize its geometry for a small scale LFR concentrator considering the optical and thermal efficiencies. At same time, a novel SPLFR concentrator was proposed and its performance was compared with that of general LFR.
• Three key components, LFR, ORC system and Desiccant-Evaporator cooling system have been numerical simulated and fabricated.
• A small-scale prototype has been constructed and tested.
• Marie Curie Actions has been also acknowledged in 2 published journal papers and one conference paper by the incoming fellow and the host researcher. In addition, one conference presentation about the project has been made and 2 research papers have been submitted to international journals.

4) the expected final results and their potential impact and use (including the socio-economic impact and the wider societal implications of the project so far).
This project is expected to provide a novel multifunctional generation system for electricity, heating, cooling/dehumidification applications. The fundamental research has been carried out and a small-scale prototype has been constructed and tested through this fellowship project. The testing results are promising and will be continuously disseminated widely to attract potential commercial interest. Development of tri-generation system using renewable energy sources is the fundamental approach to meet the EU target in cutting CO2 emissions. The proposed multifunctional generation systems are suitable for decentralized energy supply and HVAC as well, so they may play an important role in promoting solar energy applications to make a significant contribution to the EU target in cutting CO2 emissions, and hence the quality of life both within the EU and globally would be improved. Results would be of great value to industries of power generation, air conditioning and solar thermal energy. The proposed technology has the potential to find a large market both in the EU and worldwide, and would therefore bring economic benefit to EU industry. Manufacturing and application of the proposed technology would also create new job opportunities in the EU.