Theoretical Calculation And Experimental Study On Performance Of Sensible Cooling Air Conditioner In Telecommunications Base Stations

With the development and widely using of refrigeration and air conditioning equipment, the air conditioning system has been one of systems with the most energy comsumption in the world. This large energy consumption demonstrates the significant potential for energy savings. The matching with throttle device and refrigerant charge has great influence on the energy comsumption of air conditioning system. This papers presents some analyses on the effects of different lengths of capillary, thermal expansion valve(TXV) openings and refrigerant charge on performance of sensible cooling air conditioner in telecommunications base stations by theoretical calculation and experimental study.The air cooling air conditioner by sensiable cooling is a special air conditioner of cabinet whose refrigerating capacity is 400 W. This paper presents a steady model about the special air conditioner of cabinet. A lumped model for the compressor and distributed models for the condenser, evaporator and helical capillary tube are developed. The models are solved by method of sequential module. The performance of the refrigeration systerm is analyzed when the the length of capillary tube and refrigerant charge are varied. The research results indicate that the optimal combination of the length of capillary tube and refrigerant charge can make the refrigerating capacity and COP optimal. The optimal combination is 0.14 m and 120 g. The refrigerating capacity and COP are improved by 5.3% and 8.8% comparing to the combination which is 0.12 m and 160 g. Finally, a tested is conducted in the enthalpy difference laboratory. The test results are compared with calculation. The maximum relative error between the calculation and experiment is 7.43%. These research results can be used to design the products and analyze the performance of the special air conditioner of cabinet.The effects of the different TXV openings and refrigerant charge on the performance of a water cooling air conditioner by sensiable cooling whose refrigerating capacity is 5500 W is studied by experiment. The results show that the refrigerating capacity varies from 2000 W to 5500 W and it firstly increases then decreases with the increasing refrigerant charge and constant TXV opening. The optimal refrigerant charge is different from the different TXV openings. When the TXV opening is one sixth of full openings and refrigerant charge is 1900 g, the performance of system is optimal. Evaluated by carlbosch criterion, the air cooler works under the condition of dry cooling. The research results are helpful to guide the performance of products optimization.