Daikin Industries, Ltd.

Daiken Industries, Ltd.

Shigeto Tanaka

Noriyasu Kawakatsu

Hisaaki Takaoka

Makoto Ikemiya

Takashi Sugimoto

Kenji Tanimoto

Akira Horikawa

A refrigerant circuit is configured, which includes an electric compressor, a condenser, an expansion mechanism, an evaporator, a hot gas introduction path connecting the electric compressor and the evaporator together, and a switching valve for controlling a flow of refrigerant in the hot gas introduction path. In addition, a fan is provided. In a defrosting cycle for introducing refrigerant into the evaporator through the hot gas introduction path to defrost the evaporator, if the pressure of the condenser is equal to or lower than a predetermined threshold, the fan forms an air flow from a radiator to the condenser.

Trailer refrigerating apparatus

The refrigeration system has an energy saving operation mode performing: a first action in which a compressor () and an internal fan () are driven while the cooling capacity of an evaporator () is regulated; a second action in which, when the blow-off-side air temperature in a cold storage is kept at a set value in the first action, the cooling capacity of the evaporator () is increased to lower the blow-off-side air temperature to a lower limit temperature of a desired temperature range containing the set value and the compressor () and the internal fan () are then stopped; and a third action in which, when the blow-off-side air temperature after the second action rises to an upper limit temperature of the desired temperature range, the first action is restarted. Furthermore, the energy saving operation mode is configured so that when the suction-side air temperature in the cold storage after the second action rises to a limit value, the internal fan () is activated at a lower air flow rate than in the first action.

Refrigeration system having an energy saving operation

When during a first action of a refrigeration system the internal cold storage temperature is held at a desired temperature by an evaporator, the refrigeration system performs a second action of increasing the cooling capacity of the evaporator to decrease the internal cold storage temperature. When during the second action the internal cold storage temperature reaches a minimum temperature Tmin, the refrigeration system stops a compressor and performs a third action. When during the third action the internal cold storage temperature reaches a maximum temperature Tmin, the refrigeration system drives the compressor and performs the first action.

Refrigeration system

If the degree of opening of an electronic expansion valve () continues to remain below a specified degree of opening or if the degree of superheat of an evaporator () continues to remain above a predetermined degree of superheat, it is determined that the refrigerant circulation amount is in short supply in the water-cooled operation mode, and an air-cooled condenser fan () is tuned on.

If the degree of opening of an electronic expansion valve () is kept below a specified degree of opening or if the degree of superheat of refrigerant at an evaporator () side is kept above a specified degree of superheat, the amount of circulating refrigerant is judged to be insufficient. Thus, the volume of an air delivered by an evaporator fan () is reduced.

A refrigeration circuit ( ) sequentially connected to a compressor ( ), a condenser ( ), an electric expansion valve ( ), an evaporator ( ), and an intake proportional valve ( ). When the freezing capability of the refrigeration device is to be suppressed, a control means ( ) will restrict the intake proportional valve ( ) in order to place refrigerant in a discharge side of the evaporator ( ) in a wet saturated steam state, and the electric expansion valve ( ) will be set to an aperture such that the refrigerant in the interior of the evaporator ( ) will be placed in the wet saturated steam state.

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Osaka, Japan

Shigeto Tanaka