Refrigerant control system and method

Patent metadata

Field	Value
Publication number	US-2016305697-A1
Application number	US-201615195860-A
Country	US
Kind code	A1
Filing date	Jun 28, 2016
Priority date	Jul 31, 2009
Publication date	Oct 20, 2016
Grant date	—

Abstract

A refrigeration system is provided, such as for use with chillers. The system uses a tube-side condenser, such as a microchannel condenser, along with a shell-side evaporator such as a falling film evaporator. A flash tank economizer is disposed between the condenser and the evaporator, and an inlet valve to the flash tank is controlled based upon subcooling of condensate from the condenser. The vapor exiting the flash tank may be fed via an economizer line to a system compressor. Liquid phase refrigerant combined with some gas phase refrigerant exits the flash tank and is directed through an orifice before entering the evaporator.

First claim

1 . A heating, ventilating, air conditioning or refrigeration system comprising:
a condenser configured to condense refrigerant vapor into a condensate; a flash tank configured to receive the refrigerant condensate and to at least partially vaporize the refrigerant; an evaporator configured to receive refrigerant from the flash tank and to vaporize the refrigerant; a compressor configured to receive condensate vapor from the evaporator and to compress the refrigerant vapor for return to the condenser; an electronically controlled flash tank feed valve disposed between the condenser and the flash tank, configured to control flow of condensate from the condenser to the flash tank; and a control system coupled to the flash tank feed valve and configured to regulate opening and closing of the feed valve based upon subcooling of the condensate.

2 . The system of claim 1 , comprising pressure and temperature sensors disposed to sense pressure and temperature of the condensate, the control system being coupled to the pressure and temperature sensors and configured to receive signals from the sensors representative of pressure and temperature and to compute condensate subcooling based upon the signals for control of the flash tank feed valve.

3 . The system of claim 1 , comprising an orifice disposed between the flash tank and the evaporator for regulating flow of condensate from the flash tank to the evaporator.

4 . The system of claim 3 , wherein the orifice is a fixed orifice.

5 . The system of claim 3 , wherein the orifice is a variable orifice.

6 . The system of claim 1 , wherein the system is configured to permit a flow stream of refrigerant from the flash tank to the evaporator that includes liquid and vapor phase refrigerant.

7 . The system of claim 6 , wherein the flow stream is primarily liquid phase refrigerant as measured by mass.

8 . The system of claim 1 , wherein the control system is coupled to the compressor and detects or controls a parameter of the compressor representative of compressor capacity, and wherein control of the flash tank feed valve is also based upon the parameter of the compressor representative of capacity.

9 . The system of claim 8 , wherein the parameter is compressor speed.

10 . The system of claim 1 , wherein the evaporator is a shell-side evaporator.

11 . The system of claim 10 , wherein the evaporator is a falling film evaporator.

12 . The system of claim 10 , wherein the evaporator is a flooded evaporator.

13 . The system of claim 10 , wherein the evaporator is a hybrid of flooded and falling film type evaporators.

14 . The system of claim 1 , wherein the condenser is a microchannel tube condenser.

15 . The system of claim 1 , wherein the condenser is a tube and fin condenser.

16 . A heating, ventilating, air conditioning or refrigeration system comprising:
a condenser configured to condense refrigerant vapor into a condensate; a flash tank configured to receive the refrigerant condensate and to at least partially vaporize the refrigerant; a shell-side evaporator configured to receive refrigerant from the flash tank and to vaporize the refrigerant; a compressor configured to receive condensate vapor from the evaporator and to compress the refrigerant vapor for return to the condenser; an electronically controlled flash tank feed valve disposed between the condenser and the flash tank, configured to control flow of condensate from the condenser to the flash tank; an orifice disposed between the flash tank and the evaporator, configured to regulate flow of refrigerant from the flash tank to the evaporator; a pressure sensor configured to sense pressure of the condensate from the condenser and to produce a pressure signal representative thereof; a temperature sensor configured to sense temperature of the condensate from the condenser and to produce a temperature signal representative thereof; and a control system coupled to the pressure and temperature sensors and configured to receive the pressure and temperature signals and to compute subcooling of the condensate, the control system also coupled to the flash tank feed valve and configured to regulate opening and closing of the feed valve based upon subcooling of the condensate.

17 . The system of claim 16 , wherein the condenser is a microchannel tube condenser, and wherein the orifice is a fixed orifice.

18 . The system of claim 16 , wherein the condenser is a tube and fin condenser, and wherein the orifice is a fixed orifice.

19 . The system of claim 16 , wherein the condenser is a microchannel condenser, and wherein the orifice is a variable orifice.

20 . The system of claim 16 , wherein the condenser is a tube and fin condenser, and wherein the orifice is a variable orifice.

Assignees

• Johnson Controls Tech Co

Inventors

• Kopko William L
• Federman Israel
• Kulankara Satheesh
• Graybill Andrew John

Classifications

• F25B2339/024

  Evaporators with refrigerant in a vessel in which is situated a heat exchanger · CPC title

• F25B1/10

  with multi-stage compression (with cascade operation F25B7/00) · CPC title

• F25B2700/195

  of the condenser · CPC title

• F28F1/022

  with multiple channels · CPC title

• F28D21/0017

  Flooded core heat exchangers (in large body of fluid F28D1/0206) · CPC title