Vapor compression type refrigeration apparatus including leak detection and method for detecting refrigerant leaks

• US 20020139128A1
• Filed: 04/02/2002
• Published: 10/03/2002
• Est. Priority Date: 04/03/2001
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Suzuki, Takahisa, Tahara, Toshihiro, Nobuta, Tetsuji, Tsunooka, Tatsuo
• Granted Patent: US 6,681,582 B2
• Time in Patent Office: Days
• US Class Current: 62/129
• CPC Class Codes: B60H 1/3225 characterised by safety arrangements, e.g. compressor anti-seizure means or by signalling devices
• CPC Class Codes: F25B 2500/222 Detecting refrigerant leaks
• CPC Class Codes: F25B 2500/24 Low amount of refrigerant in the system
• CPC Class Codes: F25B 2700/1931 Discharge pressures
• CPC Class Codes: F25B 2700/2104 of an indoor room or compartment
• CPC Class Codes: F25B 2700/2106 of fresh outdoor air
• CPC Class Codes: F25B 2700/21173 at the outlet
• CPC Class Codes: F25B 49/005 of safety devices F25B49/02 and F25B49/04 take precedence
• CPC Class Codes: G01M 3/002 by using thermal means

Abstract

A vapor compression type refrigeration apparatus is provided, in which refrigerant leakage is detected at an early stage. A temperature difference related to the theoretical heat dissipation of the condenser is compared with the actual temperature difference in heat dissipation (temperature difference between the condensation temperature and the outside-air temperature) of the condenser to determine whether there is a refrigerant leak.

Claims

1. A vapor compression type refrigeration apparatus having a refrigeration circuit, the apparatus comprising:

a compressor;

a condenser, wherein the condenser cools high-temperature, high-pressure refrigerant compressed with the compressor;

a decompressor;

an evaporator for evaporating low-temperature, low-pressure refrigerant decompressed with the decompressor; and

means for determining the amount of refrigerant remaining in the refrigeration circuit by comparing an actual parameter related to actual heat dissipation in the condenser and a theoretical parameter related to heat dissipation in the condenser.

2. The apparatus of claim 1, wherein the means for determining the amount of refrigerant remaining in the refrigeration circuit comprises:

actual heat dissipation parameter calculation means for calculating an actual parameter related to actual heat dissipation;

theoretical heat dissipation parameter calculation means for calculating a theoretical parameter related to heat dissipation in the condenser based on data provided when a normal level of refrigerant exists in the refrigeration circuit; and

remaining refrigerant amount determination means for determining the amount of refrigerant remaining in the refrigeration circuit by comparing the parameter calculated by the actual heat dissipation parameter calculation means and the parameter calculated by the theoretical heat dissipation parameter calculation means.

3. The vapor compression type refrigeration apparatus according to claim 2, wherein the actual parameter and the theoretical parameter each represent a temperature difference between a temperature related to the temperature of refrigerant in the condenser and the temperature of cooling air sent to the condenser.

4. The vapor compression type refrigeration apparatus according to claim 2, wherein the actual parameter and theoretical parameter each represent a temperature difference in cooling air across the condenser.

5. The vapor compression type refrigeration apparatus according to claim 2, wherein the theoretical parameter is calculated based on the suction pressure of the compressor.

6. The vapor compression type refrigeration apparatus according to claim 2, wherein the theoretical parameter is calculated based on a specific enthalpy change of refrigerant in the condenser.

7. The vapor compression type refrigeration apparatus according to claim 2, wherein the theoretical parameter is calculated based on the suction pressure of the compressor, and the theoretical parameter is calculated based on a specific enthalpy change of refrigerant in the condenser.

8. The vapor compression type refrigeration apparatus according to claim 1, wherein the theoretical parameter is calculated based on the suction pressure of the compressor.

9. The vapor compression type refrigeration apparatus according to claim 1, wherein the theoretical parameter is calculated based on a specific enthalpy change of refrigerant in the condenser.

10. The vapor compression type refrigeration apparatus according to claim 1, wherein the theoretical parameter is calculated based on the suction pressure of the compressor, and the theoretical parameter is calculated based on a specific enthalpy change of refrigerant in the condenser.

11. The vapor compression type refrigeration apparatus according to claim 1, wherein the compressor is a variable-capacity type compressor that can vary its discharge capacity so that its discharge rate is directed to a predetermined value.

12. The vapor compression type refrigeration apparatus according to claim 11, wherein the theoretical parameter is calculated based on the smaller of a refrigerant flow rate calculated based on 100% compressor capacity and a maximum flow rate determined at least based on the discharge pressure of the compressor.

13. The vapor compression type refrigeration apparatus according to claim 1, wherein the compressor is a variable-capacity type compressor that can vary its discharge capacity based on the pressure difference across a throttle installed in the refrigerant circuit.

14. The apparatus of claim 1, wherein the means for determining the amount of refrigerant remaining in the refrigeration circuit comprises:

actual heat dissipation parameter calculation means for calculating an actual parameter related to actual heat dissipation;

theoretical heat dissipation parameter calculation means for calculating a theoretical parameter related to heat dissipation in the condenser based on a physical quantity related to an evaporation temperature of refrigerant in the evaporator when a normal level of refrigerant exists in the refrigeration circuit; and

remaining refrigerant amount determination means for determining the amount of refrigerant remaining in the refrigeration circuit by comparing the parameter calculated by the actual heat dissipation parameter calculation means and the parameter calculated by the theoretical heat dissipation parameter calculation means.

15. The vapor compression type refrigeration apparatus according to claim 14, wherein the actual parameter and the theoretical parameter each represent a temperature difference between a temperature related to the temperature of refrigerant in the condenser and the temperature of cooling air sent to the condenser.

16. The vapor compression type refrigeration apparatus according to claim 14, wherein the actual parameter and theoretical parameter each represent a temperature difference in cooling air across the condenser.

17. The vapor compression type refrigeration apparatus according to claim 14, wherein the theoretical parameter is calculated based on the suction pressure of the compressor.

18. The vapor compression type refrigeration apparatus according to claim 14, wherein the theoretical parameter is calculated based on a specific enthalpy change of refrigerant in the condenser.

19. The vapor compression type refrigeration apparatus according to claim 14, wherein the theoretical parameter is calculated based on the suction pressure of the compressor, and the theoretical parameter is calculated based on a specific enthalpy change of refrigerant in the condenser.

20. A vapor compression type refrigeration apparatus having a refrigeration circuit, the apparatus comprising:

a compressor;

a condenser, wherein the condenser cools high-temperature, high-pressure refrigerant compressed with the compressor;

a decompressor;

an evaporator for evaporating low-temperature, low-pressure refrigerant decompressed with the decompressor; and

means for determining an amount of refrigerant remaining in the refrigeration circuit by comparing an actual parameter related to actual heat absorption in the evaporator and a theoretical parameter related to heat absorption in the evaporator.

21. A method of detecting a shortage of refrigerant in a refrigeration circuit comprising determining the amount of refrigerant remaining in the refrigeration circuit by comparing an actual parameter related to actual heat dissipation in a condenser and a theoretical parameter related to heat dissipation in the condenser.

22. The method according to claim 21 including:

calculating an actual parameter related to actual heat dissipation;

calculating a theoretical parameter related to heat dissipation in the condenser; and

determining the amount of refrigerant remaining in the refrigeration circuit by comparing the actual heat dissipation parameter and the theoretical heat dissipation parameter.

23. The method according to claim 22, wherein the theoretical parameter is based on data provided when a normal level of refrigerant exists in the refrigeration circuit.

24. The method according to claim 22, wherein the theoretical parameter is based on a physical quantity related to an evaporation temperature of refrigerant in an evaporator when a normal level of refrigerant exists in the refrigeration circuit.