Research On Solar Energy Combined With Air Source Heat Pump Energy Supply System For Rural Residential Buildings In Jiaozuo City

Building energy consumption has always been one of the important components of China’s energy consumption.With the continuous progress of urbanization,energy saving of rural buildings is gradually receiving more and more attention.In order to improve the current unreasonable energy structure and reduce air pollution in rural areas,China has implemented policies such as "coal-to-electricity" and "coal-to-gas" in northern villages and towns.Nonetheless,the "coal-to-gas" is not so practical due to its high cost.By contrast,the air source heat pump with high energy efficiency ratio in the "coal-to-electricity" is more popular for heating in winter.However,the heating performance of single air source heat pump in cold areas may be affected by some conditions such as frost,which leads to high heating energy consumption and unsatisfactory heating effects.This paper proposes a single-tank solar energy combined with air source heat pump energy supply system for rural residential buildings,which can not only be controlled for heating and air cooling,but also make the tank provide hot water for residents at any time.This system helps to make full use of the heating and cooling capacity of the air source heat pump.In this paper,a simulation model of the compound system is built for performance simulation to verify the applicability of the system.In addition,the effects of collector area,tank volume,tank controlling temperature and collector tilt angle on system performance are determined for economic optimization of the system.And then different systems including the system before and after optimization,the single air source heat pump system,and the compound system with the collector area designed for domestic hot water load are compared and analyzed from the view of economy.Finally,this paper also analyzes the impact of changes in demand and price on the system.From this study,the results can be concluded as follows.Firstly,under the conditions in this study,the compound system has a relatively good performance throughout the year,with an average PER of 1.14 in heating season and 1.08 in year,and the residents’ demand of domestic hot water can be met with the solar collector system alone in the transition season.Increasing the heat collector area and lowering the supply temperature of the fan coil will result in improved performance of the composite system,and increased tank volume increases solar fraction,but has little impact on system PER.Furthermore,8.9% reduction in annual costs after optimization.The adjustment of the building domestic hot water demand found that the annual cost of the system using domestic hot water design collector area is lower compared to using the heating load design.From the perspective of tariff,when the collector cost is less than 200 yuan per square meter,the annual cost of the system with heating load design collector area is cheaper than the system with domestic hot water load,and when the collector cost is over 200 yuan per square meter per square meter,the result is opposite.When the tariff is adjusted,the lower the price of tariff,the greater the advantage of the annual cost of the collector area taken according to the domestic hot water load.