Research On Heating Performance Of Split Solar Heat Pump Hot Water System

In the process of using traditional solar water heater in low solar radiation area,due to the instability of solar radiation and insufficient radiation intensity,the water heater cannot heat water to the target temperature,and cannot provide hot water for residential users stably and efficiently.In view of this problem,this paper designs and establishes a split solar heat pump hot water system,the hot water system gives priority to use the solar natural circulation device to preheat the water storage tank,after the preheating is over,if the temperature does not meet the requirements,then use the heat pump device for heating to produce hot water.Firstly,according to the environmental parameters of Hanzhong area and the water load of rural single family residential buildings,the heat load of the system was determined and the main components of the system were selected and calculated.According to the selection results,a split solar heat pump hot water system was built.Secondly,the heating experiments of tap water with different capacities were carried out,and the influence of daily cumulative solar radiation and ambient temperature on the heating performance of the split solar heat pump hot water system and the power consumption of the system were studied under different working modes.Based on the experimental data,the prediction model of the system was established,and the heat loss analysis of the system was carried out.The results show that the influence of the analysis variables on the heating termination temperature.When the initial heating water temperature,the average ambient temperature and the heating water capacity are unchanged,the heating termination temperature increases by 1.45℃for every 1MJ·m^-2increase in daily cumulative solar radiation.Analyze the influence of variables on the power consumption of the system.When the heating initial water temperature and the heating water capacity are unchanged,the power consumption of the system is reduced by 0.023k Wh for every 1℃increase in the average ambient temperature.The influence of variables on the average COP of the system is analyzed.When the initial heating water temperature and the heating water capacity are unchanged,the average COP increases by 0.0658 when the average ambient temperature increases by 1℃.When the system runs under different working conditions,the heat loss of the solar plate collector has a large proportion,and the heat loss in the heat storage water tank can not be ignored.Finally,the multiple linear regression prediction model is used to calculate the energyconsumption of the system under three operating modes in different climate zones,and the annual running time distribution of the system is summarized.The results show that the maximum operation time of the system in Hetian was 133 days,while the minimum operation time in Chengdu was 77 days.Under the solar preheating+heat pump heating mode,the longest operation time of the system in Chengdu is 271 days,and the power consumption of the heat pump unit is 227.8k Wh,while the shortest operation time is 221 days in Lanzhou,and the power consumption of the heat pump unit is 235.7k Wh.Under the single heating mode of the heat pump,the longest operation time of the system in Lanzhou is 65 days,and the power consumption of the heat pump unit is 122.8k Wh,while the shortest operation time in Chengdu is 3 days,and the power consumption of the heat pump unit is 21.7k Wh.