Investigation On The Heating,power And Cooling Tri-generation Performance For The Household Roll-bond Photovoltaic Thermal Heat Pump System

Solar energy as a clean and renewable energy resource,provides a new way to solve the problem of energy shortage and environmental pollution from building sector,by the realization of its high efficient in-depth utilization and its integration with buildings.The building has the diversified energy demand and distributed energy supply forms includes heating in winter,cooling in summer,year-round power supply and domestic hot water.At present,the solar photo-thermal utilization and photovoltaic technology are both inefficient and single forms of energy utilization.The large area of solar panels is also a huge waste of land resources.Moreover,the cooling demand of buildings in summer still cannot be met with low cost and high efficiency.Therefore,this paper focuses on the further improvement of the solar energy comprehensive utilization efficiency,as well as to meet the various energy demand of the buildings at the same time.The long-wave radiant refrigeration,roll-bond heat transfer and heat pump technology are integrated into the process of comprehensive utilization of solar energy,to solve the two "integration" problems from building sector,namely,"the integration of photovoltaic and photo-thermal",and "the integration of solar heating and cooling".Therefore,on the basis of the in-depth analysis of research progress in this field and the above key problems that need to be solved,this paper proposed the roll-bond PVT unit and PVT heat pump poly-generation system.The following research works was carried out by combining theoretical analysis,experimental research and performance simulation.(1)This paper proposed the roll-bond PVT heat pump poly-generation system and the roll-bond evaporation/condensation PVT unit.The working principles of the system under various operating conditions were introduced.And the structure design method and working principles of the novel PVT unit were discussed.Moreover,based on the analysis of productivity characteristics of the system,the performance evaluation method was proposed.(2)The experimental research was carried out on the roll-bond PVT heat pump system and the roll-bond evaporation/condensation PVT unit.The optimization design and construction of the PVT heat pump experimental platform was illustrated,as well as the error analysis method of the experiment system.Through analysis,it was found that the test error of the photovoltaic and heating performance parameters of the experiment system were less than 5%,while the test error of the refrigeration performance parameters was less than 10%.(3)Based on the research requirements for the poly-generation operation mode of the roll-bond PVT heat pump system in summer and the test platform,the experimental research on the system poly-generation performance and operating characteristics was carried out.The results showed that,under natural working conditions in summer,the average photovoltaic efficiency was 13.6%,the average heating COPt of the system in the daytime was 6.16,while the average cooling COPc in the nighttime was 2.8.Compared with the conventional PV modules with same rated power,the power generation capacity of the PVT unit is increased by 10?15%.(4)The photovoltaic and heating co-generation performance as well as the operating characteristics of the experimental system in the transition and winter season was studied.The results showed that the average photovoltaic efficiency was 11.9%and the average heating COPt was 5 under the natural operating conditions in the transition season.While in winter,the average photovoltaic efficiency was 10.3%and average heating COPt was 4.4.Furthermore,the system could run steadily in each season and operation mode for a long time.(5)By means of mathematical modeling and theoretical analysis,this paper established the heat transfer model of the PVT unit as well as the mathematical model of other main components of the heat pump system.Then the experimental verification was carried out for the theoretical results.The results showed that the relative errors between the theoretical solution and the experimental results were all within 11%,which provided a theoretical basis for the system performance simulation analysis and techno-economic evaluation.(6)Based on the energy demand and energy supply form of the residential buildings with different scale,the household type PVT heat pump system was proposed.The simulation analysis for the system performance was carried out.By analyzing the influence of environmental parameters on the poly-generation performance of the system under different working conditions,the regional applicability of the proposed system was explored.On the basis of experiment and simulation results,the technical economy of the household roll-bond PVT heat pump system was analyzed,along with the discussion of the influence factors on the system economy.Then the economic operation mode of applying the system in north China was proposed.The research results showed that compared with the conventional energy supply system,the household roll-bond PVT heat pump system had a considerable annual net income with a payback period of 3-4 years.