Free cooling refrigeration system

Patent metadata

Field	Value
Publication number	US-11199356-B2
Application number	US-201013388262-A
Country	US
Kind code	B2
Filing date	Aug 12, 2010
Priority date	Aug 14, 2009
Publication date	Dec 14, 2021
Grant date	Dec 14, 2021

Abstract

A refrigeration system includes a chiller with an integrated free cooling system and refrigeration system. In certain embodiments, the chiller may be a single package unit with all equipment housed within the same support frame. The chiller may generally include three modes of operation: a first mode that employs free cooling, a second mode that employs free cooling and implements a refrigeration cycle, and a third mode that uses the free cooling system provide additional cooling capacity for the refrigeration system. The free cooling system includes an independent loop configured to transfer heat from a cooling fluid circulating within the free cooling system to the ambient air.

First claim

The invention claimed is:

1. A cooling system comprising:
a free cooling system;
a circuit of the free cooling system configured to receive a first cooling fluid from a cooling fluid loop and pass the first cooling fluid through a first heat exchanger along the circuit and back to the cooling fluid loop, wherein the first heat exchanger is configured to facilitate heat transfer from the first cooling fluid to a second cooling fluid;
a first refrigeration system configured to circulate a first refrigerant through a second heat exchanger;
an independent loop of the free cooling system configured to circulate the second cooling fluid from the first heat exchanger to the second heat exchanger and from the second heat exchanger to a first air-to-liquid heat exchanger, wherein the first air-to-liquid heat exchanger is configured to transfer heat from the second cooling fluid to ambient air and the second heat exchanger is configured to facilitate heat transfer from the first refrigerant to the second cooling fluid;
a third heat exchanger configured to receive the first cooling fluid from the cooling fluid loop, the first refrigerant, and a second refrigerant, wherein the first cooling fluid, the first refrigerant, and the second refrigerant are separate from one another in the third heat exchanger, and wherein the third heat exchanger is configured to receive the first cooling fluid from the cooling fluid loop in a first mode of system operation and in a second mode of system operation;
a second refrigeration system configured to circulate the second refrigerant from the third heat exchanger to a second air-to-liquid heat exchanger, wherein the second air-to-liquid heat exchanger is configured to transfer heat from the second refrigerant to the ambient air;
a first valve disposed along the cooling fluid loop and configured to selectively direct the first cooling fluid to bypass the free cooling system in the first mode of system operation and to sequentially direct the first cooling fluid from a cooling load to the first heat exchanger along the circuit of the free cooling system, from the first heat exchanger along the circuit of the free cooling system to the third heat exchanger, and from the third heat exchanger back to the cooling load in the second mode of system operation;
a second valve disposed along the independent loop and configured to enable a flow of the second cooling fluid through the first air-to-liquid heat exchanger in a first position and to block the flow of the second cooling fluid through the first air-to-liquid heat exchanger in a second position; and
a controller configured to adjust the second valve between the first position and the second position based on feedback received from an ambient temperature sensor.

2. The cooling system of claim 1 , wherein the second cooling fluid comprises a freeze-protected fluid.

3. The cooling system of claim 1 , wherein the second refrigeration system is a vapor-compression cycle.

4. The cooling system of claim 3 , wherein the second refrigeration system comprises:
a compressor configured to compress the second refrigerant;
the second air-to-liquid heat exchanger configured to receive and to condense the compressed second refrigerant; and
an expansion device configured to reduce pressure of the condensed second refrigerant before the second refrigerant enters the third heat exchanger.

5. The cooling system of claim 1 , wherein the first refrigeration system is a vapor-compression cycle configured to absorb heat from the first cooling fluid.

6. The cooling system of claim 1 , wherein the third heat exchanger comprises a three-fluid heat exchanger.

7. The cooling system of claim 1 , comprising a third valve disposed along the independent loop of the free cooling system and configured to selectively direct the second cooling fluid to the second heat exchanger in a first free cooling mode of operation and to bypass the second heat exchanger in a second free cooling mode of operation.

8. The cooling system of claim 1 , comprising an expansion tank disposed along the independent loop and configured to receive the second cooling fluid from the second valve, the first air-to-liquid heat exchanger, or both, wherein the expansion tank is configured to enable storage and thermal expansion of the second cooling fluid in the independent loop.

9. A refrigeration system comprising:
a free cooling system;
a heat exchanger;
a circuit of the free cooling system configured to circulate a first cooling fluid from a first cooling fluid loop through the heat exchanger to facilitate heat exchange between the first cooling fluid and a second cooling fluid and back to the first cooling fluid loop;
an independent loop of the free cooling system configured to circulate the second cooling fluid through the heat exchanger, wherein the independent loop circulates the second cooling fluid through an air-to-liquid heat exchanger configured to transfer heat from the second cooling fluid to ambient air;
a refrigeration loop configured to circulate a refrigerant through the heat exchanger on a high-pressure side of the refrigeration loop and a condenser disposed downstream of the heat exchanger, the refrigeration loop comprising an evaporator configured to form a direct heat exchange relationship between the refrigerant in the refrigeration loop upstream of the heat exchanger and the first cooling fluid directed sequentially from the heat exchanger to the evaporator, wherein the circuit of the free cooling system is configured to circulate the first cooling fluid directly from the heat exchanger to the evaporator through an uninterrupted conduit; and
a controller configured to selectively direct the first cooling fluid to bypass the free cooling system based on a sensed temperature of ambient air.

10. The refrigeration system of claim 9 , wherein the first cooling fluid has a first freezing point temperature, and wherein the second cooling fluid comprises a solution with a second freezing point temperature lower than the first freezing point temperature.

11. The refrigeration system of claim 9 , comprising a control valve disposed along the first cooling fluid loop, wherein the controller is configured to operate the control valve to selectively direct the first cooling fluid to bypass the free cooling system during certain modes of operation.

12. The refrigeration system of claim 11 , wherein the controller is configured to operate an additional control valve to selectively direct the second cooling fluid to the heat exchanger and bypass the air-to-liquid heat exchanger.

13. The refrigeration system of claim 11 , wherein the controller is configured to selectively direct the first cooling fluid to the free cooling system based on the sensed temperature of the ambient air.

14. The refrigeration system of claim 9 , wherein the controller is configured to selectively direct the second cooling fluid to bypass the air-to-liquid heat exchanger based on a sensed temperature of the first cooling fluid, the second cooling fluid, or both.

15. The refrigeration system of claim 9 , wherein the heat exchanger comprises a three-fluid heat exchanger.

16. The refrigeration system of claim 9 , wherein the heat exchanger is configured to receive the second cooling fluid into a shell side and configured to receive the first cooling fluid and the refrigerant into respective tubes.

Assignees

• Kopko William L
• Yanik Mustafa K
• Johnson Controls Tech Co

Inventors

• Kopko William L
• Yanik Mustafa K

Classifications

• F25B41/00

  Fluid-circulation arrangements · CPC title

• F25B2400/06

  Several compression cycles arranged in parallel · CPC title

• F25B25/005

  using primary and secondary systems · CPC title

• F25D16/00 Primary

  Devices using a combination of a cooling mode associated with refrigerating machinery with a cooling mode not associated with refrigerating machinery · CPC title