Evaporator liquid preheater for reducing refrigerant charge

Patent metadata

Field	Value
Publication number	US-2016178243-A1
Application number	US-201514789910-A
Country	US
Kind code	A1
Filing date	Jul 1, 2015
Priority date	Jul 1, 2014
Publication date	Jun 23, 2016
Grant date	—

Abstract

A system and method for reducing the refrigerant charge in a refrigeration system by preheating the liquid refrigerant before it is introduced to the evaporator inlet. When refrigerant liquid is introduced to the evaporator inlet, a portion of the refrigerant liquid vaporizes. This refrigerant vapor displaces refrigerant liquid at the inlet of the evaporator. As more refrigerant vapor is introduced, the amount of liquid inside the evaporator is reduced. A heat exchanger is placed before the liquid refrigerant inlet of the evaporator to generate more vapor when the refrigerant enters the evaporator.

First claim

1 . A liquid overfeed refrigeration system comprising:
a refrigerant evaporator, a refrigerant compressor, a refrigerant condenser, an expansion device, and a refrigerant pre-heater situated before the inlet of the refrigerant evaporator and configured to heat liquid refrigerant before it enters the evaporator to a temperature that is 10% to 80% of the difference between an operating temperature of the evaporator and an operating temperature of the condenser, wherein said pre-heater reduces a ratio of refrigerant charge to refrigeration capacity by at least 10%.

2 . A refrigeration system according to claim 1 , wherein said refrigerant pre-heater is a heat exchanger.

3 . A refrigeration system according to claim 2 , wherein a heat source for said pre-heater heat exchanger is warm refrigerant liquid from said refrigerant condenser.

4 . A refrigeration system according to claim 1 , further comprising a separator element configured to separate liquid and vapor refrigerant leaving said evaporator.

5 . A refrigeration system according to claim 1 , further comprising an evaporator feed pump located upstream of the evaporator.

6 . A refrigeration system according to claim 1 , further comprising a defrost system.

7 . A refrigeration system according to claim 1 , wherein said evaporator, compressor, condenser, expansion device and pre-heater are connected in a refrigerant flow path.

8 . A refrigeration system comprising:
a refrigerant evaporator having an inlet and an outlet, a liquid/vapor separator having an inlet, a vapor outlet and a liquid outlet; a refrigerant compressor having an inlet and an outlet; a refrigerant condenser having an inlet and an outlet, an expansion device having an inlet and an outlet, and a refrigerant pre-heater, having an inlet and an outlet situated before the inlet of the refrigerant evaporator; wherein said evaporator, separator, compressor, condenser, preheater, and expansion device are connected in one or more refrigerant flow paths via refrigerant line.

9 . A refrigeration system according to claim 8 , wherein said system is a liquid overfeed system.

10 . A method for reducing the refrigerant charge of a refrigeration system evaporator comprising preheating liquid refrigerant prior to introduction of the liquid refrigerant to an inlet of said evaporator inlet.

11 . A method according to claim 9 , further comprising measuring a property of said refrigerant at an inlet of said evaporator and adjusting an amount of said preheating based on said measured property.

12 . A method according to claim 10 , wherein said pre-heating the refrigerant prior to introduction of the refrigerant to the evaporator inlet reduces the refrigerant charge per ton of refrigeration capacity by 10% or greater.

13 . A method according to claim 12 , wherein said pre-heating the refrigerant prior to introduction of the refrigerant to the evaporator inlet reduces the refrigerant charge per ton of refrigeration capacity by 30% or greater.

14 . A method according to claim 10 , comprising heating said liquid refrigerant to convert 10% to 30% refrigerant vapor.

Assignees

• Evapco Inc

Inventors

• Derosier Greg

Classifications

• F25B40/06

  Superheaters · CPC title

• F25B6/04 Primary

  arranged in series · CPC title

• F25B2700/21151

  at the suction side of the compressor · CPC title

• F25B2400/23

  Separators · CPC title

• F25B2400/05

  Compression system with heat exchange between particular parts of the system · CPC title