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US 6,244,057 B1Granted
Air conditioner
AssigneeHitachi, Ltd.
InventorsYasutaka Yoshida, Susumu Nakayama, Koji Naito, Satoru Yoshida, Hiroshi Takenaka
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AssigneeHitachi, Ltd.
InventorsYasutaka Yoshida, Susumu Nakayama, Koji Naito, Satoru Yoshida, Hiroshi Takenaka
Estimating the term…
An air conditioner comprising a refrigerant forward path branching on a discharge side of a compressor in an outdoor unit, one of the branched portions being defined by connecting a first four-way valve, a first outdoor heat exchanger and a first outdoor expansion valve to one another in this order, and the other of the branched portions being defined by connecting a second four-way valve, a second outdoor heat exchanger and a second outdoor expansion valve in this order, the path extending to an indoor unit from the respective outdoor expansion valves through a liquid-side piping, and returning to the outdoor unit from the indoor unit through a gas-side piping to branch, one of the branched portions being connected to the first four-way valve via a check valve placed in communication in a forward direction and the other of the branched portions being connected to the second four-way valve, the air conditioner being controlled such that, when heating operation is switched to defrosting operation, the second four-way valve is switched if a pressure difference between discharge pressure and suction pressure of the compressor is equal to or above a predetermined value, and the first four-way valve is switched after a gas-side pressure of the second outdoor heat exchanger has risen, whereby the four-way valves are prevented from being made inoperative due to short-circuit between high pressure side and low pressure side.
An air conditioner provided with an indoor unit or units having an indoor expansion valve and an indoor heat exchanger and an outdoor unit having a compressor, a first outdoor heat exchanger, a second outdoor heat exchanger, a first four-way valve and a second four-way valve, the air conditioner comprising:
An air conditioner provided with an indoor unit or units having an indoor expansion valve and an indoor heat exchanger and an outdoor unit having a compressor, a first outdoor heat exchanger and a second outdoor heat exchanger, the air conditioner comprising:
An air conditioner provided with an indoor unit or units having an indoor expansion valve and an indoor heat exchanger and an outdoor unit having a compressor, a first outdoor heat exchanger and a second outdoor heat exchanger, the air conditioner comprising:
In an air conditioner comprising an outdoor unit, an indoor unit or units connected to said outdoor unit by a liquid-side piping and a gas-side piping, and a forward circulating path for a refrigerant, said outdoor unit being constructed such that one of pipes branching on the discharge side of a drive frequency variable type compressor is connected to a first four-way valve, a first outdoor heat exchanger and a first outdoor expansion valve in this order, the other of the pipes is connected to a second four-way valve, a second outdoor heat exchanger and a second outdoor expansion valve in this order, and outflowing sides of the said respective outdoor expansion valves join together to be connected to said liquid-side piping, and said indoor unit or units being constructed such that an indoor expansion valve and an indoor heat exchanger are connected in this order from said liquid piping side, and that one of pipes, which return to said outdoor unit from said gas-side piping connected to said indoor heat exchanger and branches, is connected to said first four-way valve via a check valve in communication in a forward direction, and the other of the pipes is connected to said second four-way valve, the refrigerant flowing along the forward circulating path at the time of cooling and defrosting operations and flowing in a direction reverse to the forward circulating path at the time of heating operation, the improvement comprising means for sensing discharge pressure of said compressor, means for sensing suction pressure of said compressor, means for sensing gas-side pressures of said respective outdoor heat exchangers, and a four-way valve control device for operating said first and second four-way valves on the basis of detected values of said respective pressures, and wherein said four-way valve control device controls, when heating operation is switched over to defrosting operation, to first switch said second four-way valve if a pressure difference between said compressor discharge pressure and said compressor suction pressure is equal to or above a predetermined value, and to switch said first four-way valve after the gas-side pressure of said second outdoor heat exchanger has risen.
Dependencies are inferred from the claim text.