Transcritical refrigerant vapor system with capacity boost

Patent metadata

Field	Value
Publication number	US-9360237-B2
Application number	US-201214112596-A
Country	US
Kind code	B2
Filing date	Apr 3, 2012
Priority date	Apr 21, 2011
Publication date	Jun 7, 2016
Grant date	Jun 7, 2016

Abstract

A refrigerant vapor compression system and method of operation are disclosed wherein the first ( 30 a ) and second ( 30 b ) compression stages of a two stage compression device are selectively configurable in a first arrangement and a second arrangement. In the first arrangement, the first and second compression stages operate in a series refrigerant flow relationship. In the second arrangement, the first and second compression stages ( 30 a ), ( 30 b ) operate in a parallel refrigerant flow relationship.

First claim

We claim:

1. A refrigerant vapor compression system comprising: a first refrigerant heat rejection heat exchanger having a refrigerant inlet and a refrigerant outlet; a second refrigerant heat rejection heat exchanger having a refrigerant inlet and a refrigerant outlet; a refrigerant compression device having a first compression stage and a second compression stage; a branch refrigerant line connecting a refrigerant inlet of the first compression stage to a refrigerant inlet of the second compression stage; a flow control device in the branch refrigerant line; the first and second compression stages and the first and second refrigerant heat rejection heat exchangers selectively configurable in a first arrangement wherein the first and second compression stages operate in a series refrigerant flow relationship and the second refrigerant heat rejection heat exchanger functions as an intercooler for cooling refrigerant passing from the first compression stage to the second compression stage, the flow control device closed in the first arrangement, and in a second arrangement wherein the first and second compression stages operate in a parallel refrigerant flow relationship and the second refrigerant heat rejection heat exchanger functions as a gas cooler for cooling refrigerant passing from the first compression stage, the flow control device open in the second arrangement.

2. A system as recited in claim 1 wherein in the second arrangement, the first rejection heat rejection heat exchanger functions as a gas cooler for cooling refrigerant passing from the second compression stage only.

3. A system as recited in claim 1 wherein in the second arrangement, the first rejection heat rejection heat exchanger functions as a gas cooler for cooling refrigerant passing from both the first compression stage and the second compression stage.

4. A refrigerant vapor compression system comprising: a refrigerant compression device having a first compression stage and a second compression stage; a first refrigerant heat rejection heat exchanger having a refrigerant inlet and a refrigerant outlet; a second refrigerant heat rejection heat exchanger having a refrigerant inlet and a refrigerant outlet; a first refrigerant line in refrigerant flow communication with a refrigerant discharge outlet of the second compression stage, the first refrigerant heat rejection heat exchanger disposed in the first refrigerant line; a second refrigerant line connecting a refrigerant discharge outlet of the first compression stage in refrigerant flow communication with a refrigerant inlet of the second compression stage, the second refrigerant heat rejection heat exchanger disposed in the second refrigerant line between the first compression stage and the second compression stage; a third refrigerant line connecting the second refrigerant line in refrigerant flow communication with the first refrigerant line, the third refrigerant line tapping into the second refrigerant line at a location; a flow control valve interdisposed in the second refrigerant line downstream with respect to refrigerant flow of the location, said flow control valve being selectively positionable between an open position and a closed position; and a check valve disposed in third refrigerant line, said check valve operative to allow refrigerant flow to pass through the third refrigerant line from the second refrigerant line to the first refrigerant line and to prevent refrigerant flow through the third refrigerant line from the first refrigerant line to the second refrigerant line.

5. A method for operating a refrigerant vapor compression system having a compression device having a first compression stage and a second compression stage, the method comprising the steps of: selectively arranging the first compression stage and the second compression stage in a series flow relationship with respect to refrigerant flow in a first mode of operation; and selectively arranging the first compression stage and the second compression stage in a parallel flow relationship with respect to refrigerant flow in a second mode of operation; wherein a branch refrigerant line connects a refrigerant inlet of the first compression stage to a refrigerant inlet of the second compression stage and a flow control device is positioned in the branch refrigerant line; wherein in the first mode of operation the flow control device is closed and in the second mode of operation the flow control device is open.

6. The method as recited in claim 5 further comprising the steps of:
passing a flow of refrigerant discharging from said second compression stage through a first refrigerant heat rejection heat exchanger; and
passing a flow of refrigerant discharging from said first compression stage through a second refrigerant heat rejection heat exchanger.

7. The method as recited in claim 6 further comprising the step of:
passing the flow of refrigerant having traversed the second refrigerant heat rejection heat exchanger to an inlet of said second compression stage in the first mode of operation.

8. The method as recited in claim 6 further comprising the step of:
passing the flow of refrigerant having traversed the second refrigerant heat rejection heat exchanger through the first refrigerant heat rejection heat exchanger thereby bypassing the second compression stage in the second mode of operation.

9. The method as recited in claim 5 wherein the second mode of operation comprises operation of the refrigerant vapor compression system in a boosted capacity non-economized mode.

10. The method as recited in claim 5 wherein the first mode of operation comprises operation of the refrigerant vapor compression system in an economized mode.

11. The method as recited in claim 5 further comprising the step of operating the refrigerant vapor compression system for refrigerating air from a cargo space of a refrigerated container for transporting perishable goods.

12. The method as recited in claim 11 further comprising the steps of:
selectively arranging the first compression stage and the second compression stage in a series flow relationship with respect to refrigerant flow when the refrigerant vapor compression system is operating in an economized mode in a first stage of pulldown of a temperature within the cargo space; and
selectively arranging the first compression stage and the second compression stage in a parallel flow relationship with respect to refrigerant flow when the refrigerant vapor compression system is operating in a boosted capacity non-economized mode in a second stage of pulldown of a temperature within the cargo space.

Assignees

• Huff Hans-Joachim
• Carrier Corp

Inventors

• Huff Hans-Joachim

Classifications

• F25B2400/075

  with parallel compressors · CPC title

• F25B2400/072

  Intercoolers therefor · CPC title

• F25B2400/23

  Separators · CPC title

• F25B6/04

  arranged in series · CPC title

• F25B1/10 Primary

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