Refrigeration – Automatic control – Preventing – removing or handling atmospheric condensate
Patent
1995-06-15
1997-11-25
Tanner, Harry B.
Refrigeration
Automatic control
Preventing, removing or handling atmospheric condensate
62156, 62278, F24F 1102, F25B 4702
Patent
active
056899645
DESCRIPTION:
BRIEF SUMMARY
This invention relates to an operation control device for air conditioner, and particularly relates to measures for controlling the start of defrosting operation.
There is a conventional air conditioner in which a compressor, a four-way selector valve, a thermal-source-side heat exchanger, an expansion valve for heating provided together with a non-return valve, an expansion valve for cooling provided together with a non-return valve, and a used-side heat exchanger are sequentially connected, as disclosed in the Japanese Patent Application Laid-Open Gazette No.61-114042. This air conditioner performs defrosting operation when a fin of the thermal-source-side heat exchanger is frosted in heating operation.
Further, before starting the defrosting operation, the air conditioner deactivates a used-side fan and performs heat storage in the used-side heat exchanger with high-pressure refrigerant. Then, with the refrigerant thus heated, the air conditioner performs the defrosting operation in a cooling cycle so as to complete it with efficiency for a short time.
In the above control of defrosting operation, however, since the heat storage is executed only with the used-side fan deactivated before the start of defrosting operation and the expansion valves are fully opened, the defrosting operation is started with liquid refrigerant stored in the thermal-source-side heat exchanger. Thus, an amount of heat of condensation is not only used for dissolving frost but also dissipated into low-temperature refrigerant such as liquid refrigerant.
As a result, not only the amount of heat of condensation is not effectively used for dissolving frost but also a part of the thermal-source-side heat exchanger in which liquid refrigerant is stored is not used as an area for condensation of gas refrigerant, thereby presenting the problems of low defrosting performance and long-time defrosting operation.
In view of the foregoing problems this invention has been made. An object of this invention is to use the amount of heat of condensation of refrigerant only for dissolution of frost while increasing an area for condensation of refrigerant, thereby enhancing defrosting performance and reducing a defrosting time.
To achieve the above object, measures instituted in this invention are so composed as to fully close an expansion mechanism before defrosting operation is executed.
More specifically, as shown in FIG. 1, a measure instituted in the invention premises an air conditioner comprising a refrigerant circuit (9) in which a compressor (1), a thermal-source-side heat exchanger (3) having a thermal-source-side fan (3f), an expansion mechanism (5) freely adjustable in opening and a used-side heat exchanger (6) having a used-side fan (6f) are sequentially connected and which is operable in at least heating cycle operation.
Further, there is provided defrosting requiring means (11) for outputting a defrosting requiring signal to require defrosting operation.
Furthermore, there is provided refrigerant recovering means (12) for fully closing the opening of the expansion mechanism (5) with the refrigerant circuit (9) in a heating cycle when the defrosting requiring means (11) outputs a defrosting requiring signal, thereby recovering refrigerant.
In addition, there are provided completion determining means (14) for determining whether the recovery of refrigerant by the refrigerant recovering means (12) is completed and defrosting executing means (15) for executing defrosting operation when the completion determining means (14) outputs a completion signal that the recovery of refrigerant is completed.
A measure instituted in the invention further comprises heat-storage operating means (13) for deactivating the used-side fan (6f) when the defrosting requiring means (11) outputs a defrosting requiring signal, thereby implementing heat storage in the used-side heat exchanger.
A measure instituted in the invention is so composed that the refrigerant circuit (9) is reversibly operable between cooling cycle operation and heating cycle operation and
REFERENCES:
patent: 4688392 (1987-08-01), Fujimoto et al.
patent: 4901534 (1990-02-01), Nakatsuno et al.
patent: 4979371 (1990-12-01), Larson
Kawakita Hiroyuki
Takagi Satoshi
Tsutsumi Hideki
Brackett Jr. Tim L.
Daikin Industries Ltd.
Ferguson Jr. Gerald J.
Tanner Harry B.
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