Refrigerant distribution apparatus and methods for transport refrigeration system

Patent metadata

Field	Value
Publication number	US-9909786-B2
Application number	US-201113576051-A
Country	US
Kind code	B2
Filing date	Mar 7, 2011
Priority date	Mar 8, 2010
Publication date	Mar 6, 2018
Grant date	Mar 6, 2018

Abstract

A method for distributing a refrigerant charge level in a refrigerant vapor compression system includes restarting a stopped refrigerant compression device in a first mode; operating a primary expansion device independent of refrigerant heat absorption heat exchanger superheat; comparing a condition at a refrigerant reservoir to a prescribed condition; wherein when the condition is below the prescribed condition for a prescribed interval, operating the primary expansion device to control the refrigerant heat absorption heat exchanger superheat; and transitioning the refrigerant vapor compression system to a second mode.

First claim

We claim:

1. A method for distributing a refrigerant charge level in a refrigerant vapor compression system, the refrigerant vapor compression system having a refrigerant circuit including a refrigerant compression device, a refrigerant heat rejection heat exchanger downstream of said compression device, a refrigerant reservoir downstream of the heat rejection heat exchanger, a refrigerant heat absorption heat exchanger downstream of said refrigerant reservoir, and a primary expansion device disposed in the refrigerant circuit downstream of said refrigerant heat rejection heat exchanger and upstream of said refrigerant heat absorption heat exchanger, said method comprising:
operating the refrigerant compression device at a speed;
stopping the refrigerant compression device;
after the refrigerant compression device has stopped, restarting the refrigerant compression device in a first mode;
in the first mode, setting the primary expansion device to a prescribed degree of opening;
in the first mode, comparing a condition at the refrigerant reservoir to a prescribed condition;
in the first mode, in response to the condition being below the prescribed condition for a prescribed time interval transitioning the refrigerant vapor compression system to a second mode, the second mode comprising operating the primary expansion device to control the refrigerant heat absorption heat exchanger superheat;
wherein the condition is a pressure condition and the prescribed condition is a prescribed pressure threshold;
wherein the prescribed pressure threshold is a critical refrigerant pressure.

2. The method of claim 1 , wherein, in the first mode, in response to the condition being above the prescribed condition:
pulsing an economizer solenoid valve in a refrigerant vapor line coupling the refrigerant reservoir to an intermediate port of the refrigerant compression device.

3. The method of claim 1 , wherein, in the first mode, in response to the condition being above the prescribed condition:
pulsing a liquid injection valve in a liquid injection line between the refrigerant reservoir and an inlet port of the refrigerant compression device.

4. The method of claim 1 , wherein the refrigerant vapor compression system is configured to use C0 2 refrigerant.

5. The method of claim 1 , wherein setting the primary expansion device to a prescribed degree of opening includes increasing an opening of the primary expansion device by a set amount.

6. The method of claim 1 , wherein the second mode is an economized mode.

7. A method for distributing a refrigerant charge level in a refrigerant vapor compression system, the refrigerant vapor compression system having a refrigerant circuit including a refrigerant compression device, a refrigerant heat rejection heat exchanger downstream of said compression device, a refrigerant reservoir downstream of the heat rejection heat exchanger, a refrigerant heat absorption heat exchanger downstream of said refrigerant reservoir, and a primary expansion device disposed in the refrigerant circuit downstream of said refrigerant heat rejection heat exchanger and upstream of said refrigerant heat absorption heat exchanger, said method comprising:
operating the refrigerant compression device at a speed;
stopping the refrigerant compression device;
after the refrigerant compression device has stopped, restarting the refrigerant compression device in a first mode;
in the first mode, setting the primary expansion device to a prescribed degree of opening;
in the first mode, comparing a condition at the refrigerant reservoir to a prescribed condition;
in the first mode, in response to the condition being below the prescribed condition for a prescribed time interval transitioning the refrigerant vapor compression system to a second mode, the second mode comprising operating the primary expansion device to control the refrigerant heat absorption heat exchanger superheat;
further comprising sensing pressure at the refrigerant reservoir using a sensor, wherein the condition is a supercritical condition of the refrigerant in the refrigerant reservoir, wherein the refrigerant vapor compression system is configured to use C0 2 refrigerant.

8. The method of claim 7 , wherein the second mode is an economized mode.

9. The method of claim 7 , wherein prior to operating in the first mode, operating the refrigerant compression device with an unload service valve open; and draining refrigerant from the refrigerant reservoir using a downstream refrigerant flow control device.

10. The method of claim 7 , wherein setting the primary expansion device to a prescribed degree of opening includes increasing an opening of the primary expansion device by a set amount.

Assignees

• Liu Lucy Yi
• Duraisamy Suresh
• Hofsdal Gilbert B
• Huff Hans Joachim
• Patriak Michal
• Carrier Corp

Inventors

• Liu Lucy Yi
• Duraisamy Suresh
• Hofsdal Gilbert B
• Huff Hans Joachim
• Patriak Michal

Classifications

• B60H1/3228

  characterised by refrigerant circuit configurations · CPC title

• F25B2700/19

  Pressures · CPC title

• F25B2500/26

  characterised by the startup of the refrigeration cycle · CPC title

• F25B2700/21173

  at the outlet · CPC title

• F25B2600/0261

  external to the compressor · CPC title