System Simulation And Optimization Of Absorption Refrigerating System Driven By Solar Heat Source

With the rapid development of society,the energy consumption of air-conditioning is increasing day by day.It has become an important issue for the moment about how to reduce the energy consumption of building and improve the quality of life.Solar absorption refrigerating machine is widely concerned with the reason that it can use low grade energy,environmental care and good cooling effect.Considering the efficiency of the solar collector,it is the best choice for the residential application to select the single effect LiBr-H₂O absorption chiller.Air-cooled system shows the superiority in the application of residential solar cooling with the characteristics of saving water,space and maintenance cost,but there are high crystallization risk and miniaturization difficulty.Therefore,it is of great significance to optimize it.In this paper,the simulation and application are studied about the air-cooled single effect absorption chiller with adiabatic evaporator and absorber.Avoid the heat change between the cooling water and chilled water by introducing the adiabatic flash process,reduce the chilled water circulating pump and the evaporator tube in the traditional water cooling system;The traditional absorber is replaced by the adiabatic absorber with precooled exchanger,the absorption heat is discharged by the supercool,and mass transfer occurs only in the absorber.In this way,it can increase COP and cooling capacity and also reduce power consumption with smaller size and lower material cost.The system simulation model of the novel air-cooling chiller is designed by using Aspen Plus software whose cooling capacity is 5kW,the results were analyzed about the effects of evaporation temperature,temperature,condensing temperature and the results were analyzed about the effects of evaporation temperature,temperature,condensing temperature,flow rate and concentration of the weak solution on the system.With the increase of the evaporation temperature from 5?to 15?,the COP increased from 0.61 to 0.82,and the cooling capacity increased from 1.5kW to 8.8kW,when the evaporation temperature increased from 5?to 11?,the COP increased a lot from 0.61 to 0.78,which increased by 27.3%,from 11?to 15?,the COP increased by 5.1%.The deflated range of the single effect LiBr refrigerator is between0.03⁰.06,when the condensing temperature is set to 35?,the lowest temperature is 78?,the maximum can't exceed 86?,when the condensing temperature is set to 40?,the lowest temperature is 83 C,the maximum can't exceed 90?,when the condensing temperature is set to 45?,the lowest temperature is 89?,the maximum can't exceed 98?;With the increase of flow rate and concentration of weak solution,the COP of the system tends to decrease,while the change of temperature is opposite.When the concentration of weak solution increased from 56.5%to 59.9%,the cooling capacity only decreased by 0.045kW,less than 1%,and the COP decreased from 0.712 to 0.705;The influence is analyzed about the mutual compensation on each parameter,the increase of evaporation temperature by 3.7?can compensate for the temperature difference between the hot water about 10?.Through the result analysis and comparison with the water cooling system,we know that the variation of each parameter has the same influence on the system,and the most obvious difference are the generating temperature and the flow rate of the weak solution.At the temperature of 35?,40?and 45?,the lowest temperature of water-cooling system and air-cooling system are 82.5?/77?,89.9?,/83?,95.5?,/89?respectively,the highest temperature is 90.1?/84?,96.3?/90?,102.5?/98?respectively,the temperature range is7.6?/7?,6.4?/7?and 7?/9?,and the highest and lowest temperature of water-cooling system is higher than that of air-cooling system,and the difference is between 4.5-7?,the flow rate of weak solution of the air-cooling system is 6.3%larger than that of the water-cooled chilled water system.The refrigeration building model is set up by using Trnsys software,the maximum cooling load in the cooling season is 37.089kW so the needed effective collector area of the evacuated tube collector is 138.25m².The application situation is analyzed about the novel air-cooled chiller in the expert villa,when solar energy is sufficient,the average temperature of the supply and return water about chilled water?refrigerant?in the summer can reach9.31?and 14.72?,the temperature difference is 5.41?,which can meet the indoor cooling demand.