Patent ID: 11927379
Assignee: XI'AN JIAOTONG UNIVERSITY
Field: Thermal processes and apparatus (Mechanical engineering)
Classification: CPC F  Y | IPC F

Claim 7:
8. The control method claim 6, comprising:
accurately assessing a defrosting effect of the CO2 heat pump system based on measurement values of the evaporation fin temperature sensor and an evaporation pressure sensor; and determining that a frost layer on the CO2 evaporator has been eliminated as long as one of following three conditions is met, exiting the defrosting mode, and restarting a normal heating process, wherein the following three conditions lie in that: a temperature of evaporation fins of a unit exceeds a setting defrosting ending temperature; an evaporation pressure of the unit exceeds a setting defrosting ending pressure; and an accumulated defrosting time of the unit reaches a maximum setting defrosting time; and
when the defrosting mode exits, returning the opening degree of the electronic expansion valve to a memory value of a last normal operation, closing the defrosting solenoid valve, returning the opening degree of the waterway two-way regulating valve to a memory value of a last normal operation, and starting the fan of the CO2 evaporator to a memory rotating speed of the last normal operation, in such a manner that an effective pressure difference is established as soon as possible in the system, and the system is recovered to a normal heating state.