| Because of the significant advantage, the multi-spilt air-conditioning systems havebecome dominated for commercial and residential buildings in recent years. At presentthe research about low part load performance for multi-spilt air-conditioning systems isnot sufficient enough. In this paper the mathematical model is built for simulating thesystem performance. Based on the simulation results, the system performanceparameters are calculated and analyzed, and the theoretical reference has been offeredfor designing and application of the inverter multi-spilt air-conditioning system.The research object of this paper is the multi-spilt air-conditioning system K-1which was installed in school of Environmental and Municipal Engineering of Xi’anUniversity of Architecture and Technology. The mathematical model of the invertercompressor, condenser, electronic expansion valve and evaporator are established inMATLAB and SIMULINK programming language. A thermodynamic model of theair-conditioned room is also built. Further more, based on the mutual couplingrelationship analysis of the various component parameters, the system numericalsimulation model is established. Finally the performances of the multi-spiltair-conditioning system are studied and analyzed when the system is running in partialload conditions.The performance characteristics and EER in the system are studied and comparedunder part load rate16%and24%. Compared to operation with one single indoor unit,the system performance would be different with two indoor units opening at the sametime. And its EER value is2.18, slightly higher than the system with a single indoor unitwhich EER is2.14.When the outside air temperature is changed form31℃to39℃, the performance on part load rate16%is also studied. The condensing pressure and refrigerant flow bothincrease with the rise of outdoor air temperature. The actual power of invertercompressor increases from1.34kW to2.12kW. At the same time, refrigeration capacityper unit decreases, but actual capacity of the system increases from3.4kW to4.47kW.Finally, the energy efficiency ratio value reduces from2.43to2.07, with the increase ofoutdoor air temperature. Compared to operation with one single indoor unit, the actualcapacity of the system with two indoor units at the same time has increased35%, and a33%increase in the total power consumption of the inverter compressor.The performance characteristics and EER in the system are studied under thecontinuous operation with one single indoor unit. The refrigeration capacity and theactual power of inverter compressor of multi-spilt air-conditioning system decrease afterincreasing over time, and the EER increases after the first drop. |
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