Electronic expansion valve control during the start-up of refrigeration system

The parameters of refirigeration system change largely and rapidly during the start-up. If the electronic expansion valve is used as throttle device, the control strategy is different from that of stable operation. The performance of thermostatic expansion valve during the start-up was analyzed. It is found that the superheat may be zero for a long time. A new index, Zero Superheat Time, was put forward, and applied to the electronic expansion valve control. Further, the control strategy of electronic expansion valve to improve the Zero Superheat Time during the start-up was put forward. The test results show that it works well.