Air conditioning system including pressure control device and bypass valve

Patent metadata

Field	Value
Publication number	US-9605885-B2
Application number	US-201313826552-A
Country	US
Kind code	B2
Filing date	Mar 14, 2013
Priority date	Mar 14, 2013
Publication date	Mar 28, 2017
Grant date	Mar 28, 2017

Abstract

An air conditioning system includes: first and second utilization side heat exchangers and a heat source side heat exchanger respectively connected in series; a compressor connected between the first utilization side heat exchanger and the heat source side heat exchanger; an expansion valve connected between the first utilization side heat exchanger and the second utilization side heat exchanger; a pressure control device connected between the second utilization side heat exchanger and the heat source side heat exchanger; and a bypass valve connected between the expansion valve and the heat source side heat exchanger. The bypass valve provides a variable amount of liquid refrigerant flowing from the expansion valve to the heat source side heat exchanger. The pressure control device and the bypass valve cooperate with each other to keep a temperature of the compressor below a maximum allowable temperature predetermined for the compressor.

First claim

What is claimed is:

1. An air conditioning system, comprising:
first and second utilization side heat exchangers and a heat source side heat exchanger respectively connected in series;
a compressor connected between the first utilization side heat exchanger and the heat source side heat exchanger;
an expansion valve connected between the first utilization side heat exchanger and the second utilization side heat exchanger, the expansion valve comprising first and second expansion valves connected in series;
a bypass valve connecting piping at an outlet of the heat source side heat exchanger with piping between the first expansion valve and the second expansion valve during a defrost system operation; and
a pressure control device connected between the second utilization side heat exchanger and the heat source side heat exchanger; and,
wherein
the pressure control device is configured to maintain refrigerant that flows from the second utilization side heat exchanger to the heat source side heat exchanger at a predefined pressure,
the bypass valve is configured to make refrigerant from the expansion valve bypass the second utilization side heat exchanger and the pressure control device, and
the pressure control device and the bypass valve are configured in cooperation with each other to keep a temperature of the compressor below a maximum allowable temperature predetermined for the compressor.

2. The air conditioning system according to claim 1 , further comprising:
a temperature sensing device configured to detect an outdoor air temperature, wherein
the bypass valve is further configured to be opened when the air temperature detected by the temperature sensing device is lower than a predetermined value.

3. The air conditioning system according to claim 1 , further comprising:
a temperature sensing device configured to detect an outdoor air temperature, wherein
the bypass valve is further configured to provide a variable amount of refrigerant flowing therethrough, and be controlled in opening degree thereof, based on the air temperature detected by the temperature sensing device.

4. The air conditioning system according to claim 1 , further comprising:
a temperature sensing device configured to detect a temperature of the refrigerant discharged from the compressor that is correlated with the temperature of the compressor,
wherein the bypass valve is further configured to be controlled based on the temperature of the refrigerant detected by the temperature sensing device.

5. The air conditioning system according to claim 1 , further comprising:
a pressure sensing device configured to detect a pressure of the refrigerant discharged from the compressor that is correlated with the temperature of the compressor,
wherein the bypass valve is further configured to provide a variable amount of refrigerant flowing therethrough, and to be controlled in an opening degree thereof, based on the pressure of the refrigerant detected by the pressure sensing device.

6. The air conditioning system according to claim 1 , further comprising:
a controller including a central processing unit (CPU) that is configured to control the air conditioning system under normal system operation during which the refrigerant flows from the heat source side heat exchanger through the compressor to the first utilization side heat exchanger, and to control the air conditioning system under defrost system operation during which the refrigerant flows in reverse.

7. The air conditioning system according to claim 6 , further comprising:
a four-way valve that can be selectively switched between the normal system operation and the defrost system operation, wherein
during the normal system operation, the four-way valve is configured to connect an outlet of the compressor and the first utilization side heat exchanger and an inlet of the compressor and the heat source side heat exchanger, and during the defrost system operation, the four-way valve is configured to connect the outlet of the compressor and the heat source side heat exchanger and the inlet of the compressor and the first utilization side heat exchanger.

8. The air conditioning system according to claim 1 , wherein, during normal system operation,
the first utilization side heat exchanger is configured to operate as a heating unit,
the second utilization side heat exchanger is configured to operate as a cooling unit, and
the heat source side heat exchanger is configured to operate as a cooling unit.

9. An air conditioning system, comprising:
first and second utilization side heat exchangers and a heat source side heat exchanger respectively connected in series;
a compressor connected between the first utilization side heat exchanger and the heat source side heat exchanger;
an expansion valve connected between the first utilization side heat exchanger and the second utilization side heat exchanger, the expansion valve comprising first and second expansion valves connected in series;
a bypass valve connecting piping at an outlet of the heat source side heat exchanger with piping between the first expansion valve and the second expansion valve during a defrost system operation; and
a pressure control device connected between the second utilization side heat exchanger and the heat source side heat exchanger
wherein
the pressure control device is configured to maintain refrigerant that flows from the second utilization side heat exchanger to the heat source side heat exchanger at a predefined pressure, and
the bypass valve is configured to provide a variable amount of liquid refrigerant flowing from the expansion valve to the heat source side heat exchanger.

10. The air conditioning system according to claim 9 , wherein
during a defrost system operation, the bypass valve is configured to provide refrigerant flowing from the heat source side heat exchanger to the expansion valve.

11. The air conditioning system according to claim 9 , further comprising:
a controller including a central processing unit (CPU) that is in communication with the air conditioning system, wherein the controller is configured to control the bypass valve to provide the variable amount of refrigerant to the heat source side heat exchanger.

12. The air conditioning system according to claim 10 , further comprising:
a controller including a central processing unit (CPU) that is in communication with the air conditioning system, wherein
the controller is configured to control the bypass valve to provide the refrigerant that flows from the heat source side heat exchanger to the expansion valve.

13. A controller including a central processing unit (CPU) that is in communication with an air conditioning system, the air conditioning system including:
first and second utilization side heat exchangers and a heat source side heat exchanger, respectively connected in series;
a compressor connected between the first utilization side heat exchanger and the heat source side heat exchanger;
an expansion valve connected between the first utilization side heat exchanger and the second utilization side heat exchanger, the expansion valve comprising first and second expansion valves connected in series;
a bypass valve connecting piping at an outlet of the heat source side heat exchanger with piping between the first expansion valve and the second expansion valve during a defrost system operation; and
a pressure control device connected between the second utilization side heat exchanger and the heat source side heat exchanger,
and
the CPU being configured to execute instructions to cause, during normal system operation:
the pressure

Assignees

• Hatanaka Kensaku
• Shinozaki Kazuyoshi
• Bush Joseph Paul
• Flynn Peter Christian
• Mitsubishi Electric Corp

Inventors

• Hatanaka Kensaku
• Shinozaki Kazuyoshi
• Bush Joseph Paul
• Flynn Peter Christian

Classifications

• F25B2313/0234

  in series arrangements · CPC title

• F25B49/02 Primary

  for compression type machines, plants or systems · CPC title

• F25B2313/0231

  with simultaneous cooling and heating · CPC title

• F25B2313/02322

  during defrosting · CPC title

• F25B2313/02741

  using one four-way valve · CPC title