Study Of A Solar Ejector And Indirect Evaporation Coupled Cooling System

With the rapid development of society and the continuous advancement of human civilization,energy shortages and environmental pollution are becoming more and more important.It is of great significance to use environmentally friendly and clean renewable energy sources for air-conditioning applications.On the basis of previous studies on the composite cooling of solar-ejector cooling and other cooling systems,this paper presents a solar-ejector and indirect evaporation coupled cooling system.Based on the performance characteristics of the two subsystems in the coupled system,the semi-arid region of Lanzhou,Gansu Province was selected.The city conducts the following research on the coupling system for the study site:1.A solar energy ejector and indirect evaporation coupled cooling system was constructed.The indirect evaporative cooling sub-system adopts an evaporative condenser and an indirect evaporative cooler in one form.When the jet refrigeration subsystem operates,it functions as a condenser.A calculation model of the system-related components was established.The thermodynamicanalysis of the system working process was combined with the chart to design the operation strategy of the coupling system.From 8:00 to 13:00 in the morning,the indirect evaporative cooling subsystem provides cooling for the air-conditioned room;from 14:00 to 18:00,the solar-injection refrigeration subsystem provides cooling for the air-conditioned room to achieve the best operating state and maximum coupling system.Degree of energy conservation;2.According to the basic structure and working principle of the ejector,based on three laws and gas dynamics,the calculation model of the ejector is established.The injection coefficient and ejector structure under design conditions are calculated by using the injector design program written in the Fortran language.size;3.Based on the climatic characteristics of Lanzhou region,the TRNSYS software was used to calculate the hourly cooling load of the office room during the cooling season,and the solar collector system was simulated.The direct evaporative cooler and the indirect evaporative cooler were compared with the solar energy from three aspects respectively.The suitability of cooling when the ejector cooling system is coupled.The results show that: 1)Under the premise of ensuring the indoor temperature,after the indirect evaporative cooler is cooled,the relative humidity of the indoor air is between 45% and 60%,and the comfort level can meet the first-grade standard,and the direct evaporative cooler provides After cooling,the relative humidity is above 60%,in the second-degree comfort range,and the comfort level is low;2)The indirect evaporative cooler can run longer than the direct evaporative cooler,effectively reducing the operating time of the injection refrigeration subsystem,thereby reducing The area of the heat collector greatly reduces the initial investment of the system;3)The air quality of the indirect evaporative cooler after cooling is higher,and the indoor air quality is good,which is conducive to the improvement of the staff'sphysical health and work efficiency.That is,the coupling of indirect evaporative cooling with the injection refrigeration system is more appropriate;4.Study the influence of outdoor weather parameters on the performance of the two subsystems in different time periods.The results show that the lower the wet bulb temperature is,the lower the air temperature of the indirect evaporative cooling subsystem is,the smaller the required air supply volume is,the larger the cooling capacity and the lower the energy consumption;the greater the solar irradiance,the more the converted heat energy is,The greater the cooling capacity of the solar ejector cooling subsystem.Based on this,a reasonable allocation of the operating time of the two subsystems,giving full play to their cooling advantages and achieving continuous cooling of the system;5.An evaporative condenser was proposed for the solar injection refrigeration subsystem,and the effects of different types of condensers on the performance of the jet refrigeration subsystem were compared.The results show that when the refrigerant flows through the evaporative condenser,the condensation temperature is the lowest,the corresponding injection coefficient and refrigeration capacity are the maximum,and the thermal performance coefficient of the system is higher;6.Analysis of the cooling capacity,power consumption,and overall performance of the coupled system on a typical day and throughout the cooling season.The results show that: the maximum daily indirect evaporative cooling subsystem is 17.72,the maximum solar injection subsystem is 10.8,and the average ejector refrigeration subsystem is small.Therefore,increasing the operating time of the indirect evaporative cooling subsystem is beneficial to improve the system's synthesis.Coefficient of performance;the cooling rate of the entire cooling season for the cooling load to meet the rate of 100%,in which the indirect evaporative cooling subsystem cooling capacity of 100.04 kWh,can provide 47% of the cooling capacity for air-conditioned rooms;the same coolingcapacity conditions,the traditional The power consumption of the compression system is 635.05 kWh,and the coupled system consumes 126.37 kWh,which can save 80% of the energy.The daily average comprehensive performance coefficient of the coupled system is about 13 which is much higher than that of the traditional compression refrigeration system,showing excellent working performance and development.potential.