PURPOSE: To avoid a dangerous state of a compressor to be broken due to returning of liquid by a method wherein a difference between a temperature of refrigerant detected by a central temperature sensor and a temperature of gaseous refrigerant detected by a gas pipe temperature sensor is applied as a degree of over-heating and an indoor expansion valve is operated to open when this degree of over-heating becomes large and opened when the degree of over-heating is deceased.
CONSTITUTION: A central temperature sensor 11 detects a temperature of refrigerant (t2) near a central part of an indoor heat exchanger 7, and a gas pipe temperature sensor 12 detects a temperature (t). A degree of over-heating t3-t2 is calculated by an over-heating degree calculating means 15a with t2 being applied as a saturation gas temperature. An indoor side expansion valve 8 is operated such that this valve is opened when this over-heating degree is increased and the valve is closed when the over-heating degree is decreased. Accordingly, even in the case that non-azeotropic mixture is used as the refrigerant, it is possible to perform a proper control of the indoor side expansion valve 8 during cooling operation, so that the operation performs a liquid compression by returning liquid to the compressor 1 and further it is possible to avoid dangerous state in which the compressor 1 is broken.
| JPS5773356 | REFRIGERATION SYSTEM |
| JPH1123076 | SUCTION PIPE OF FREEZER |
| JP3903766 | EJECTOR |
KURACHI MASAO
KITAYAMA HIROSHI
KANEKO TAKASHI
