Device for quick-defrosting without compressor stop of the evaporator in an air-water heat pump and for running the heat pump at extremely low evaporative temperature and extremely low voltages

摘要

The present invention relates to a heat pump. It comprises a cooling medium circuit consisting of a compressor (101), a condenser (102), a cooling medium supply (103), an expansion valve (104) and an evaporator (105). A control unit (106) which controls its function is also associated with the circuit. The heat pump comprises a by-pass channel (200) by-passing at least the cooling medium supply (103) and the expansion valve (104), and having a by-pass valve (201) provided in the by-pass channel (200). Alternatively, the by-pass channel (200) by-passes also the condenser (102). The bypass valve (201) is configured to be operated externally between its three alternative positions, fully closed, fully open and open to a reduced extent, respectively, corresponding to the three alternative operation modes of the heat pump, normal operation, defrosting operation and power reduce operation. A control unit operates the bypass valve (201) between its three alternative positions.