| Under the background of advocating energy structure reform and striving to achieve carbon peak and carbon neutral,China has been promoting the development of renewable energy.Solar photovoltaic thermal heat pump system is a new energy-saving and environment-friendly heating and cooling system,which makes full use of solar energy,air energy and space cooling energy.China has a vast territory,and there are differences in building load and meteorological conditions in different regions.Solar PVT module and heat pump system are greatly affected by the changes of outdoor meteorological conditions.In order to promote the use of PVT heat pump technology in different regions,comprehensive and accurate outdoor meteorological parameters are needed to guide the design and equipment selection of PVT heat pump system.The traditional heat pump air-conditioning system is designed statically according to its nominal operating conditions,ignoring the influence of outdoor meteorological parameters on its capacity performance.However,the capacity of PVT heat pump system is closely related to the solar radiation intensity,outdoor air temperature and other meteorological parameters,and it needs to be combined with energy storage technology.Therefore,this paper will focus on the nominal working condition of PVT heat pump system,the reasonable value of outdoor design working condition parameters,and the determination of heat pump capacity.First of all,in order to study the operation performance of PVT heat pump system under different working conditions,this paper introduces and analyzes the system composition,operation mode and working principle.On this basis,the performance simulation mathematical model of the system is established,and the accuracy of the model is verified.In addition,combined with the design requirements and performance evaluation methods of heat pump products,based on repeated experimental data,investigation of domestic and foreign heat pump standards and theoretical analysis,the nominal heating and cooling conditions of PVT heat pump products are proposed.Secondly,based on the mathematical model of heating and cooling cycle of PVT heat pump system,the influence of outdoor air temperature,solar radiation intensity and wind speed on its heating performance and the influence of outdoor air temperature and wind speed on its refrigeration performance are simulated and analyzed;Then,the representative cities in different thermal zones of buildings in China are selected as the objects,and the outdoor meteorological distribution characteristics of each region are analyzed statistically.By using the above simulation model,the differences of capacity results between the single point working condition design and the hourly working condition design on the design day are compared and analyzed.It is expounded that the hourly outdoor design working condition on the design day in winter should be given in the heating selection design of PVT heat pump system The necessity of outdoor design parameters of various regions is given in refrigeration type selection design.Finally,referring to the statistical method of outdoor meteorological parameters of air conditioning in current national specifications and standards,the reasonable selection method of outdoor design parameters of solar PVT heat pump in winter and summer is proposed,and the outdoor design parameters of PVT heat pump system in 31 provinces and cities of China are calculated.Reasonable system optimization design is helpful to improve economy and equipment utilization.Finally,in order to further standardize and simplify the engineering design process,this paper puts forward the selection method of engineering application design of refrigeration type and heating type PVT heat pump equipment.Based on the principle of system energy saving and economy,using the mathematical model of refrigeration cycle and heating cycle of solar PVT heat pump system,the refrigeration type and heating type PVT heat pump system is compiled based on Matlab GUI development environment Design and selection software of heating PVT heat pump system.The capacity performance of heating and cooling per unit capacity of PVT heat pump system under different operating conditions and modes is calculated by using the above design and selection software,and the economic analysis is carried out by taking a building in Dalian as an example.The results show that the lower the outlet temperature of chilled water,the shorter the payback period;The shorter the operation time,the longer the payback period;For the PVT heat pump system selected according to the user’s refrigeration demand,the payback period of investment is much shorter than that of considering only refrigeration when the heat,power and cooling triple unit is selected.With the shortening of operation time,the payback period of investment of the system is decreasing.For the PVT heat pump system selected according to the heat load demand of users,the payback period decreases with the increase of the designed outlet water temperature,and increases with the shortening of the operation time;For the PVT heat pump system selected according to the heat demand,the payback period of investment is shorter than that of thermal power unit when the thermal power unit is selected.Therefore,in order to meet the needs of users for the design and selection of heat pump system,priority should be given to the heat,electricity and cold cogeneration units.This paper defines the nominal conditions of heating and cooling of solar PVT heat pump system,and provides a reference for the standard formulation of PVT heat pump unit.According to the distribution characteristics of climate conditions in China,a reasonable method to determine the outdoor design parameters is proposed.The outdoor design parameters of 31 provinces and cities in China in winter and summer are calculated,which provides reference data for the application and promotion of solar PVT heat pump system. |
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