Research On Performance Of Double-loop Photovoltaic Photothermal Hybrid Heat Pump Hot Water System

In order to improve the solar photovoltaic loop heat pipe hot water system at higher temperature conditions,the photoelectric and photothermal efficiency of the system is low,this paper improves the solar photovoltaic collector/evaporator,combined with the advantages of high performance water source heat pump,design A dual-loop photovoltaic solar thermal composite heat pump hot water system is presented.The system provides part of the electricity while meeting the hot water demand in daily life,which helps to achieve the goal of building energy saving and emission reduction.In this paper,through the combination of theoretical analysis and simulation,the operating characteristics of the improved system are analyzed,the operating performance of the two systems before and after the improvement in the subtropical climate zone is studied,and the effects of the structure and operating parameters on the system performance are analyzed.Based on seasonal energy analysis,the socio-economic benefits of the system and its feasibility in the climate zone are further discussed.The research content of this article includes the following aspects:(1)In view of the unfavorable working conditions caused by the excessively high operating temperature of the solar photovoltaic loop heat pipe hot water system,the photovoltaic and solar thermal efficiency is reduced.The compound method and operation control strategy of the improved system are determined,and the main components of the system are selected and parameterized.(2)In order to study the operating performance of the system,based on the first law of thermodynamics,the mathematical model of solar photovoltaic loop heat pipe operation mode and solar photovoltaic loop heat pipe + water natural circulation heat storage mode was established,and the calculation program was written with Visual Basic 6.0;Based on the transient simulation software TRNSYS,a simulation model of the solar-assisted water source heat pump operating mode was established.(3)Based on the built model,the simulation and comparative analysis of the performance of the two systems before and after the improvement of the solar photovoltaic collector/evaporator under typical daily operating conditions and throughout the summer operating conditions.Different degrees of improvement;analysis of the effect of different photovoltaic coverage and water natural circulation heat storage starting temperature on system performance,the results show that the smaller the photovoltaic coverage and the lower the starting temperature,the more beneficial it is to improve the system's photoelectric,photothermal performance;The social-economic benefits of the system before and after the solar photovoltaic heat collector/evaporator structure show that the improved system has good energy-saving benefits,environmental benefits,and economic benefits.The results prove that the improved system has better performance and is more suitable for application and promotion in subtropical regions.