Variable evaporating temperature control strategy for VRV system under part load conditions in cooling mode

Control strategy is key technology for efficient and reliable operation of air conditioning system. Although VRV research is booming in recent years, the general control strategy of VRV system is still to regulate refrigerant flow rate while keeping evaporating temperature or discharge pressure constant during cooling or heating process. In this paper, a novel control strategy with variable evaporating temperature is explored under part load conditions. Based on running point determined by original control strategy, the new strategy further reduces running frequency under the same part load conditions. Correspondingly, energy consumption reduces and evaporating temperature rises. Theoretical analysis proves its feasibility of energy saving. Further experimental results show that the novel control strategy would help to improve VRV system energy efficiency and reduce cooling energy consumption especially for part load conditions lower than 50%.