Patent ID: 7617694

Claim:
A method for controlling a super-heating degree in a heat pump system, comprising: operating the heat pump system; receiving a low pressure at a low pressure part of a compressor, a high pressure at a high pressure part of the compressor, and a discharging temperature of the compressor; computing an absorption temperature of the compressor by adding a stored absorption super-heating degree value at the low pressure part to a saturated temperature value of a refrigerant at the low pressure part; computing a reversible compression point which would result from a reversible compressing process being performed on a refrigerant at the absorption temperature; computing a present discharging super-heating degree from a difference between a reversible compression temperature at the reversible compression point and the received discharging temperature of the compressor; and controlling the system so that the present discharging super-heating degree of the compressor remains within a predetermined range.