Refrigerating and air-conditioning apparatus for use in a defrosting operation

Patent metadata

Field	Value
Publication number	US-9797648-B2
Application number	US-201114344339-A
Country	US
Kind code	B2
Filing date	Sep 13, 2011
Priority date	Sep 13, 2011
Publication date	Oct 24, 2017
Grant date	Oct 24, 2017

Abstract

A refrigerating and air-conditioning apparatus performs, even during a heating operation under air conditions leading to formation of frost, a defrosting operation while simultaneously continuing a heating operation and that improves comfort through heating by ensuring an appropriate amount of ventilation. A plurality of refrigeration cycles that are capable of independently performing a heating operation and a defrosting operation, are provided. A ventilation damper of an indoor unit in which a refrigeration cycle that performs a defrosting operation is installed is closed during a defrosting operation, and a ventilation damper of an indoor unit in which a refrigeration cycle that performs a heating operation is installed is controlled to achieve a required amount of ventilation corresponding to the indoor ventilation state.

First claim

The invention claimed is:

1. A refrigerating and air-conditioning apparatus for use in a defrosting operation comprising:
a plurality of refrigeration cycles that each include a compressor, a four-way valve, an outdoor heat exchanger, a pressure reducing device, and an indoor heat exchanger, the compressor, the four-way valve, the outdoor heat exchanger, the pressure reducing device, and the indoor heat exchanger being connected to one another, the plurality of refrigeration cycles being configured to independently perform a heating operation and a defrosting operation;
a plurality of indoor units in each of which the indoor heat exchanger for respective one of the refrigeration cycles is disposed, and that each include an indoor fan for taking in outside air through a ventilation port and blowing the air into a room and a ventilation damper that opens and closes the ventilation port; and
a controller that controls the ventilation damper of each of the indoor units,
wherein
the plurality of indoor units are installed in a same room,
the controller, when at least one of the refrigeration cycles performs defrosting operation and another at least one of the refrigeration cycles perform the heating operation, renders the ventilation damper to be in a closed state during the defrosting operation, and controls the ventilation damper of the indoor unit that performs the heating operation, and
wherein the controller is configured to,
activate a second refrigeration cycle of the plurality of refrigeration cycles from a stopped condition to start the heating operation,
start the defrosting operation in a first refrigeration cycle of the plurality of refrigeration cycles after the second refrigeration cycle is activated to start the heating operation,
terminate the defrosting operation and stop the compressor of the first refrigeration cycle after terminating the defrosting operation, and
cause the second refrigeration cycle to continue the heating operation even after the first refrigeration cycle terminates the defrosting operation.

2. The refrigerating and air-conditioning apparatus for use in a defrosting operation of claim 1 ,
wherein the controller is configured to
perform the heating operation in a third refrigeration cycle and a fourth refrigeration cycle of the plurality of refrigeration cycles,
start the defrosting operation in the third refrigeration cycle, while keeping the fourth refrigeration cycle in the heating operation,
terminate the defrosting operation of the third refrigeration cycle, and
cause the third refrigeration cycle to stop after performing the defrosting operation.

3. The refrigerating and air-conditioning apparatus for use in a defrosting operation of claim 1 ,
wherein the controller is configured to
perform a preliminary heating operation to ensure a time-averaged required heating capacity, including a period during which the defrosting operation is being performed, by controlling the refrigeration cycle that is to perform a defrosting operation to control a heating capacity before performing the defrosting operation, and
start the defrosting operation after termination of the preliminary heating operation.

4. The refrigerating and air-conditioning apparatus for use in a defrosting operation of claim 1 ,
wherein the controller is configured to control the four-way valve to cause a refrigerant to flow in a direction opposite a direction in which a refrigerant flows during the heating operation, as the defrosting operation.

5. The refrigerating and air-conditioning apparatus for use in a defrosting operation of claim 4 ,
wherein the controller, in the defrosting operation, is configured to
stop the indoor fan of the indoor unit of a refrigeration cycle that is to perform the defrosting operation, and
stop an outdoor fan for blowing air to an outdoor heat exchanger that is to be subjected to defrosting.

6. The refrigerating and air-conditioning apparatus for use in a defrosting operation of claim 1 ,
wherein the controller, in the defrosting operation, is configured to
operate the indoor fan of the indoor unit of a refrigeration cycle that is to perform the defrosting operation, when a heating load is smaller than or equal to a predetermined value, and
stop the indoor fan of the indoor unit when the heating load is greater than the predetermined value.

7. The refrigerating and air-conditioning apparatus for use in a defrosting operation of claim 1 , further comprising:
an outside air temperature detecting sensor,
wherein the controller, in the defrosting operation, is configured to
operate an outdoor fan that blows air to the outdoor heat exchanger that is to be subjected to defrosting when an outside air temperature detected by the outside air temperature detecting sensor is at or above a predetermined value, and
stop the outdoor fan that blows air to the outdoor heat exchanger that is to be subjected to defrosting when the outside air temperature detected by the outside air temperature detecting sensor is below the predetermined value.

8. The refrigerating and air-conditioning apparatus for use in a defrosting operation of claim 1 , further comprising an outside air temperature detecting sensor,
wherein when an outside air temperature detected by the outside air temperature detecting sensor is at or above a predetermined value, as the defrosting operation, the controller stops the compressor and operates an outdoor fan that blows air to the outdoor heat exchanger that is to be subjected to defrosting.

9. The refrigerating and air-conditioning apparatus for use in a defrosting operation of claim 1 , further comprising:
a bypass pipe that branches off between the indoor heat exchanger and the pressure reducing device and that reaches a suction side of the compressor via a flow control unit; and
an internal heat exchanger that exchanges heat between a refrigerant between the indoor heat exchanger and the pressure reducing device and a refrigerant that has passed through the flow control unit in the bypass pipe,
wherein in the heating operation, part of the refrigerant between the indoor heat exchanger and the pressure reducing device is caused to flow into the bypass pipe and to be depressurized by the flow control unit, and after the depressurized refrigerant is subjected to heat exchange with the refrigerant between the indoor heat exchanger and the pressure reducing device in the internal heat exchanger, the depressurized refrigerant that has been subjected to heat exchange is injected to a compression chamber of the compressor.

10. The refrigerating and air-conditioning apparatus for use in a defrosting operation of claim 1 , wherein
the plurality of refrigeration cycles are configured to not start to perform the defrosting operation
during a period in which at least one of the plurality of refrigeration cycles is performing a defrosting operation, or
during a predetermined period of time after returning from the defrosting operation to a heating operation.

11. The refrigerating and air-conditioning apparatus for use in a defrosting operation of claim 1 , wherein
when at least one of the refrigeration cycles performs the defrosting operation and another at least one of the refrigeration cycles performs the heating operation, the controller is configured to control the ventilation damper of the indoor unit that performs the heating operation to achieve a required amount of ventilation corresponding to the indoor ventilation state.

Assignees

• Ishikawa Tomotaka
• Nomoto So
• Mitsubishi Electric Corp

Inventors

• Ishikawa Tomotaka
• Nomoto So

Classifications

• F25B2313/0233

  in parallel arrangements · CPC title

• B60H2001/00961

  comprising means for defrosting outside heat exchangers · CPC title

• B60H1/00899

  Controlling the flow of liquid in a heat pump system (controlling the properties of the refrigerant liquid, e.g. pressure or temperature, B60H1/3204) · CPC title

• B60H2001/00942

  comprising a plurality of heat exchangers, e.g. for multi zone heating or cooling · CPC title

• F24F1/0003

  characterised by a split arrangement, wherein parts of the air-conditioning system, e.g. evaporator and condenser, are in separately located units · CPC title