Refrigeration system

• US 20100064723A1
• Filed: 09/08/2006
• Published: 03/18/2010
• Est. Priority Date: 09/09/2005
• Status: Active Grant

• Current Assignee: Daikin Industries Ltd
• Original Assignee: Daikin Industries Ltd
• Inventors: Kawakatsu, Noriyasu
• Granted Patent: US 7,886,549 B2
• Time in Patent Office: Days
• US Class Current: 62/507
• CPC Class Codes: F25B 2339/047 Water-cooled condensers
• 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 2600/111 of condenser fans
• CPC Class Codes: F25B 2600/21 Refrigerant outlet evaporator temperature
• CPC Class Codes: F25B 2600/2513 Expansion valves
• CPC Class Codes: F25B 49/027 Condenser control arrangements
• CPC Class Codes: F25B 6/04 arranged in series
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

If the degree of opening of an electronic expansion valve (14) continues to remain below a specified degree of opening or if the degree of superheat of an evaporator (15) continues to remain above a predetermined degree of superheat, it is determined that the refrigerant circulation amount is in short supply in the water-cooled operation mode, and an air-cooled condenser fan (21) is tuned on.

Claims

1. A refrigeration system comprising:

(a) a refrigerant circuit in which a compressor, an air-cooled condenser, a water-cooled condenser, an electronic expansion valve, and an evaporator are connected and through which a refrigerant is circulated to operate a refrigeration cycle and (b) an air-cooled condenser fan for supplying air to the air-cooled condenser,

the refrigeration system being so configured as to operate selectively either (i) in an air-cooled operation mode in which the refrigerant is passed through the air-cooled condenser in a state with the air-cooled condenser fan turned on and through the water-cooled condenser in a state with the supply of cooling water stopped, or (ii) in a water-cooled operation mode in which the refrigerant is passed through the air-cooled condenser in a state with the air-cooled condenser fan turned off and through the water-cooled condenser in a state with the supply of cooling water provided,

the degree of opening of the electronic expansion valve either being regulated in response to the degree of superheat of the refrigerant leaving the evaporator or being forcibly decreased if the high pressure of the refrigerant circuit becomes higher than a specified pressure,

wherein the refrigeration system includes controller means which turns on the air-cooled condenser fan if it is determined during the water-cooled operation mode that the amount of circulation of the refrigerant through the refrigerant circuit is in short supply.

2. The refrigeration system of claim 1, wherein the controller means determines that the refrigerant circulation amount is in short supply if the degree of superheat of the refrigerant leaving the evaporator continues to remain above a specified degree of superheat for a predetermined period of time, and then turns on the air-cooled condenser fan.

3. The refrigeration system of claim 1, wherein the controller means determines that the refrigerant circulation amount is in short supply if the degree of opening of the electronic expansion valve continues to remain below a specified degree of opening for a predetermined period of time, and then turns on the air-cooled condenser fan.

4. The refrigeration system of claim 1, wherein the compressor is formed by a compressor of the scroll type.