Temperature control apparatus and method of operating the same

• US 6,910,341 B2
• Filed: 09/26/2003
• Issued: 06/28/2005
• Est. Priority Date: 09/26/2003
• Status: Expired due to Term

• Current Assignee: Thermo King Corporation (Trane Technologies plc)
• Original Assignee: Thermo King Corporation (Trane Technologies plc)
• Inventors: Srichai, Panaya Robert, Mohs, William Francis, Ludwig, Bradley Michael
• Primary Examiner(s): Tapolcai, William E.
• Application Number:
  US10/672,776
• Publication Number:
  US 20050066671A1
• Time in Patent Office: 641 Days
• Field of Search: 621/59, 621/74, 621/964, 622/08, 622/09
• US Class Current: 62/115
• CPC Class Codes: B60H 1/00914 where the flow direction of the refrigerant does not change and there is a bypass of the condenser
• CPC Class Codes: B60H 1/3213 for increasing the efficiency in a vehicle heat pump
• CPC Class Codes: B60H 2001/00961 comprising means for defrosting outside heat exchangers
• CPC Class Codes: F25B 2327/001 of the internal combustion type
• CPC Class Codes: F25B 2400/0403 for the condenser
• CPC Class Codes: F25B 2400/0411 for the expansion valve or capillary tube
• CPC Class Codes: F25B 2400/16 Receivers
• CPC Class Codes: F25B 2400/19 Pumping down refrigerant from one part of the cycle to another part of the cycle, e.g. when the cycle is changed from cooling to heating, or before a defrost cycle is started
• CPC Class Codes: F25B 27/00 Machines, plants or systems, using particular sources of energy F25B30/06 takes precedence
• CPC Class Codes: F25B 2700/21172 at the inlet
• CPC Class Codes: F25B 2700/21173 at the outlet
• CPC Class Codes: F25B 40/00 Subcoolers, desuperheaters or superheaters
• CPC Class Codes: F25B 41/20 Disposition of valves, e.g. of on-off valves or flow control valves expansion valves F25B41/31
• CPC Class Codes: F25B 47/022 hot gas defrosting
• CPC Class Codes: F25B 49/02 for compression type machines, plants or systems
• CPC Class Codes: F25D 11/003 Transport containers

Abstract

A temperature control unit and a method of operating a temperature control unit. The temperature control unit including a refrigeration circuit enclosing a refrigerant and having a compressor, a condenser, and an evaporator coil. The method including providing a first flow path extending through the compressor, the condenser, and the evaporator, providing a second flow path extending through the compressor and the evaporator, the second flow path bypassing a section of the refrigeration circuit, directing refrigerant through the first flow path during operation in a cooling mode, directing refrigerant through the second flow path during operation in a heating mode, and recovering refrigerant from the section of the refrigeration circuit during operation in a recovery cycle.

Claims

1. A method of operating a temperature control unit, the temperature control unit including a refrigeration circuit housing a refrigerant and having a compressor, a condenser, and an evaporator coil, the method comprising:

providing a first flow path extending through the compressor, the condenser, and the evaporator;

providing a second flow path extending through the compressor and the evaporator, the second flow path bypassing a section of the refrigeration circuit;

directing refrigerant through the first flow path during operation in a cooling mode;

directing refrigerant through the second flow path during operation in a heating mode; and

recovering refrigerant from the section of the refrigeration circuit during operation in a recovery cycle;

wherein the temperature control unit defines an air inlet and an air outlet and the method further comprises;

providing an efficiency range;

measuring an air inlet temperature;

measuring an air outlet temperature;

calculating a temperature change between the air inlet temperature and the air outlet temperature; and

initiating the recovery cycle when the temperature change is outside the efficiency range.

2. The method of claim 1, wherein the section of the refrigeration circuit includes the condenser.

3. The method of claim 1, wherein the refrigeration circuit includes a receiver tank, and wherein recovering refrigerant from the section of the refrigeration circuit during operation in the recovery cycle includes directing refrigerant through the first flow path to increase pressure in the receiver tank.

4. The method of claim 1, wherein recovering refrigerant from the section of the refrigeration circuit during operation in the recovery cycle includes interrupting the flow of refrigerant through the second flow path and directing refrigerant through the first flow path.

5. A method of operating a temperature control unit, the temperature control unit defining an air inlet and an air outlet and including a refrigeration circuit enclosing a refrigerant and having a compressor, a condenser, and an evaporator coil positioned between the air inlet and the air outlet, the method comprising:

providing an efficiency range;

providing a first flow path extending through the compressor, the condenser, and the evaporator;

providing a second flow path extending through the compressor and the evaporator, the second flow path bypassing a section of the refrigeration circuit;

measuring an air inlet temperature;

measuring an air outlet temperature;

calculating a temperature change between the air inlet temperature and the air outlet temperature; and

initiating a recovery cycle when the temperature change is outside the efficiency range, the recovery cycle removing substantially all of the refrigerant from the section of the refrigeration circuit.

6. The method of claim 5, further comprising directing refrigerant through the first flow path during operation in a cooling mode, and directing refrigerant through the second flow path during operation in a heating mode.

7. The method of claim 5, wherein the section of the refrigeration circuit includes the condenser.

8. The method of claim 5, wherein the refrigeration circuit includes a receiver tank, and wherein recovering refrigerant from the section of the refrigeration circuit during operation in the recovery cycle includes directing refrigerant through the first flow path to increase the pressure in the receiver tank.

9. The method of claim 5, wherein recovering refrigerant from the section of the refrigeration circuit during operation in the recovery cycle includes interrupting the flow of refrigerant through the second flow path and directing refrigerant through the first flow path.

10. A method of operating a temperature control unit, the temperature control unit including a refrigeration circuit enclosing a refrigerant and including a compressor, a condenser, and an evaporator coil, the method comprising:

providing a first flow path extending through the compressor, the condenser, and the evaporator;

providing a second flow path extending through the compressor and the evaporator, the second flow path bypassing a section of the refrigeration circuit;

directing refrigerant through the first flow path during operation in a cooling directing refrigerant through the second flow path during operation in a heating mode; and

interrupting the heating mode and removing refrigerant from the section of the refrigeration circuit;

wherein the temperature control unit defines an air inlet and an air outlet and the method further comprises;

providing an efficiency range;

measuring an air inlet temperature;

measuring an air outlet temperature; and

calculating a temperature change between the air inlet temperature and the air outlet temperature; and

wherein interrupting the heating mode and removing refrigerant from the section of the refrigeration circuit includes removing refrigerant from the section of the refrigeration circuit when the temperature change is outside the efficiency range.

11. The method of claim 10, wherein removing refrigerant from the section of the refrigeration circuit includes directing refrigerant through the first flow path.

12. The method of claim 10, wherein the refrigeration circuit includes a receiver tank, and wherein removing refrigerant from the section of the refrigeration circuit includes directing refrigerant through the first flow path to increase pressure in the receiver tank.

13. A temperature control unit comprising:

a refrigeration circuit having a refrigerant and including a compressor, a condenser, an evaporator coil, and a valve;

a first flow path extending through the compressor, the condenser, the evaporator, and the valve;

a second flow path extending through the compressor, the evaporator, and the valve, the second flow path bypassing a section of the refrigeration circuit, the valve having a first orientation, in which refrigerant is directed along the first flow path, and a second orientation, in which refrigerant is directed along the second flow path;

a controller in communication with the valve and operable to move the valve between the first orientation and the second orientation, the controller moving the valve toward the first orientation to remove refrigerant from the section of the refrigeration circuit during operation in a recovery cycle;

an air inlet and an air outlet, the evaporator coil being arranged between the air inlet and the air outlet;

a first temperature sensor positioned adjacent to the air inlet to record an inlet temperature, the first temperature sensor being in communication with the controller; and

a second temperature sensor positioned adjacent to the air outlet to record an outlet temperature, the second temperature sensor being in communication with the controller, the controller calculating a difference between the inlet temperature and the outlet temperature and initiating the recovery cycle when the difference between the inlet temperature and the outlet temperature is outside a predetermined range.

14. The temperature control apparatus of claim 13, wherein the temperature control apparatus is operable in a cooling mode and a heating mode, and wherein the controller moves the valve to the first orientation during operation in the cooling mode and moves the valve to the second orientation during operation in the heating mode.