Experimental Study On A Integrated System Of Refrigerant Pump And Vapor Compression Based On Utilization Of Natural Cold Energy

With the fast development of IT industry,the number of data centers is increasing,and also energy consumption of data centers is becoming more.The energy consumption of air conditioning system account for approximately 40% of the total energy consumption for data centers,and the potential savings are huge.The energy consumption of air conditioning system could be effectively reduced with the use of natural cold energy in winter and transition seasons.In this paper,an integrated refrigeration system of refrigerant pump and vapor compression based on utilization of natural cold energy was designed.The thermal performance of vapor compression cycle and refrigerant pump-driving cycle were compared based on the pressure-enthalpy diagram,and the refrigerant volume and system pressure drop of refrigerant pump-driving cycle were calculated.The experimental prototype of the integrated refrigeration system was set up after refitting the existing split air conditioner,the operating performance of which under different experimental conditions was studied.The refrigerating capacity of refrigerant pump-driving cycle increased firstly and then decreased with the increase of input frequency for refrigerant pump,and the refrigerating capacity was the largest when the input frequency was 20 Hz.The refrigerating capacity could be effectively regulated by adjusting the air volume for indoor unit.With the increase of ambient temperature,the refrigerating capacity and energy efficiency ratio(EER)for pump-driving cycle decreased,and the rangeability of evaporating temperature was less than that of condensing temperature.In addition,the system pressure drop of refrigerant pump-driving cycle decreased with the increase of ambient temperature.It was found that the EER of pump-driving cycle was much stronger than that of vapor compression cycle by comparing the experimental results.If the ambient temperature was below-3?,100% target refrigerating capacity could be supplied by pump-driving cycle,and it could meet 80% and 50% target refrigerating capacity when the ambient temperature was below 3.2 ? and 12 ?,respectively.Finally,the energy-saving effect and applicability of the integrated refrigeration system were studied in different climate zones in China,and it was found that the system had a good energy saving effect.The main achievement of this study is to provide theoretical support and technological reserve for promotion of the integrated refrigeration system of refrigerant pump and vapor compression in data centers,advancing energy savings for data centers.