Simulation And Experimental Study Of Solar Absorption Refrigeration System

With the rapid development of the global economy,the demand for energy in the world is increasing day by day.However,the traditional fossil energy,coal,oil and natural gas are non-renewable.Overexploitation and utilization are depleting fossil energy.Therefore,the development of new energy technology is an important measure to replace conventional fossil fuels.The solar energy resource of our country is very rich.And solar energy,as a clean and pollution-free renewable energy,has the characteristics of unrestricted distribution,consistent energy grade and building energy consumption demand.At present,solar energy systems have been widely used in daily life,such as solar water heaters have been widely used throughout our country.Chlorofluorocarbons(CFC)and hydrofluorocarbons(HCFC)refrigerants used in compressed refrigerators can cause ozone layer destruction and threaten the living environment of human beings.The research on solar lithium bromide absorption refrigeration system conforms to the environmental protection concept of sustainable development.Firstly,the mathematical model of solar lithium bromide absorption refrigeration system is established and simulated.1)The thermal properties of lithium bromide solution are fitted and calculated.The model of absorption refrigeration machine is established based on MATLAB.The simulation of lithium bromide absorption refrigeration system driven by solar energy with heat boiler is carried out with TRNSYS.Research shows:(1)For Tianjin,when the inclination of the vacuum tube collector is 45 degrees and the area of the collector is 70 square meters,the performance of the solar collector system is the best.(2)If the refrigeration system can run continuously throughout the year,the required auxiliary heat source needs 800 hours to open,heat required for auxiliary heat source is 19200 kW,total heat requirement of refrigeration system for the whole year is 2798 kW,and 68.6% of the solar energy guaranteed rate corresponding to the solar collector system.2)Based on TRNSYS and the meteorological data in Tianjin,the operation of a 60 square meter residential solar driven refrigeration system on a typical summer day is simulated and calculated,The results show that under the condition that the solar collector provides heat source,the cooling capacity generated by the operation of the refrigeration system can meet the cooling load demand of the building in summer.On the basis of simulation calculation,the economy and environmental protection of absorption refrigeration system driven by solar energy and boiler are analyzed.The results show that the carbon emission of absorption refrigeration is 84792.5 kg less than vapor compression refrigeration(R22)and reduces carbon emissions by 40%,when the unit operates at full load and the auxiliary heat source opens at 800 hours per year.An experimental platform for lithium bromide absorption refrigeration system driven by solar energy and boiler is built.By studying the influence of external parameters on performance of lithium bromide absorption refrigeration system driven by solar energy and boiler,it is concluded that with the increase of inlet temperature of heat source water,the refrigeration capacity increases and the COP increases;with the increase of inlet temperature of cooling water,the refrigeration capacity decreases and COP decreases;with the increases of outlet temperature of chilled water,the refrigeration capacity increase and COP increase.The increase of cooling water flow has the same effect on the performance of refrigerators as the decrease of cooling water temperature;with the increase of cooling water flow has little effect on the refrigeration capacity and COP of refrigerators.In order to verify the validity of the simulation model,the simulation results are compared with the experimental results.The results show that the error between the experimental values and the simulation values is less than 10%.The simulation results can provide reference for the engineering application of the lithium bromide absorption refrigeration system driven by solar energy and boiler.