Study On Matching Characteristics Of Solar Air Energy Heat Pump System

With the rapid growth of China’s economy,the energy consumption of building air conditioning and heating is increasing rapidly,and the problems such as energy shortage and environmental pollution caused by burning traditional fossil energy for heating are becoming increasingly prominent.The task of developing and utilizing clean and renewable energy is extremely urgent.Solar energy and air energy are two kinds of inexhaustible renewable energy,which have been highly valued and favored in recent years.Air source heat pump has the advantages of small size and high efficiency,which can replace coal-fired central heating and plays an important role in the heat pump application market.At present,solar assisted air source heat pump system is a common air source heat pump system,which combines the advantages of solar energy system and air source heat pump.It solves the problem that a single solar energy system can not guarantee heat supply in the case of insufficient solar radiation.However,in the course of the experiment,it is found that the heat pump unit is greatly affected by the outdoor environment,such as dry bulb temperature and solar radiation intensity,and the initial unit design makes the components of the unit can not match it during operation.Based on this,this paper studies the matching characteristics of different components of the unit under static and dynamic conditions,and designs the optimal unit parameters to maximize the system performance of the heat pump unit as much as possible.In order to achieve high efficiency and stability during the operation of the unit,it is necessary to adjust the electronic expansion valve.However,the research on the operation strategy of solar / air energy heat pump under the influence of solar radiation is not involved.In this paper,based on the study of the matching characteristics of various components,combined with experiments,the operation strategy of electronic expansion valve under the influence of solar radiation is studied.The research on the operation strategy of electronic expansion valve under the influence of solar radiation shows that under the same outdoor environmental conditions,the opening of EEV reaches the maximum value of about 52%.In order to ensure the efficient operation of the unit,the opening can not be blindly increased in the process of EEV regulation and control,it should be kept at the critical value as far as possible,and attention should be paid to the phenomenon of overshoot in EEV design.Affected by solar radiation,the EEV regulation range of SIASHP is 12.5% higher than that of conventional units.According to this characteristic,the SIASHP unit can also maintain stable operation without failure when the solar radiation intensity is within the range of 0-450 W/㎡;when the solar radiation intensity reaches the 450 W/ ㎡,the EEV opening of the SIASHP unit will fluctuate,resulting in unstable operation of the unit,so when the solar radiation intensity is greater than the 450 W/㎡,the EEV opening can be automatically adjusted within the range of 20%-80% through automatic detection of solar radiation intensity.Therefore,in the design of the unit,the automatic control device should synthesize the superheat and the solar radiation intensity to adjust the EEV.When the solar radiation is lower than the 450 W/㎡,it can be adjusted by detecting the superheat.When the solar radiation intensity is greater than 450 W/㎡,the solar radiation intensity is detected to regulate the EEV opening.