US-20260126223-A1 - HYDRONIC FREE COOLING CHILLER WITH SUBCOOLING

US20260126223A1US 20260126223 A1US20260126223 A1US 20260126223A1US-20260126223-A1

Abstract

A cooling system includes a refrigeration circuit and a coolant circuit for cooling a working fluid to meet a cooling demand. The coolant circuit is thermally coupled to the refrigeration circuit. A free cooling circuit is in selective thermal communication with the refrigeration circuit and is in selective thermal communication with the coolant circuit.

Inventors

Michel Grabon
Alexis GUY

Assignees

CARRIER CORPORATION

Dates

Publication Date: 20260507
Application Date: 20251105

Claims (20)

1 . A cooling system comprising: a refrigeration circuit; a coolant circuit for cooling a working fluid to meet a cooling demand, the coolant circuit being thermally coupled to the refrigeration circuit; and a free cooling circuit in selective thermal communication with the refrigeration circuit and in selective thermal communication with the coolant circuit.
2 . The cooling system of claim 1 , wherein the refrigeration circuit includes a heat rejection heat exchanger and the free cooling circuit includes a first heat exchanger positioned directly adjacent to the heat rejection heat exchanger.
3 . The cooling system of claim 2 , further comprising a fan operable to move a flow of air across the first heat exchanger and the heat rejection heat exchanger in series, the first heat exchanger being upstream from the heat rejection heat exchanger relative to the flow of air.
4 . The cooling system of claim 2 , wherein the free cooling circuit includes a subcooler heat exchanger and the free cooling circuit is thermally coupled to the refrigeration circuit at the subcooler heat exchanger.
5 . The cooling system of claim 4 , wherein the first heat exchanger and the subcooler heat exchanger are arranged in series relative to a flow of free cooling fluid within the free cooling circuit.
6 . The cooling system of claim 4 , wherein the subcooler heat exchanger is arranged downstream from the heat rejection heat exchanger relative to a flow of refrigerant circulating through the refrigeration circuit.
7 . The cooling system of claim 4 , wherein the free cooling circuit includes a main return conduit and a first free cooling bypass conduit arranged in parallel, the first free cooling bypass conduit being fluidly connected to an inlet of the subcooler heat exchanger.
8 . The cooling system of claim 7 , further comprising: a second free cooling bypass conduit fluidly connecting an outlet of the subcooler heat exchanger to the main return conduit; a valve disposed within the main return conduit; and another valve disposed within the second free cooling bypass conduit.
9 . The cooling system of claim 8 , wherein the inlet of the first free cooling bypass conduit is fluidly connected to the main return conduit upstream from the valve and the outlet of the second free cooling bypass conduit is fluidly connected to the main return conduit downstream from the valve.
10 . The cooling system of claim 1 , wherein the free cooling circuit includes a second heat exchanger, the free cooling circuit being thermally coupled to the coolant circuit at the second heat exchanger.
11 . A cooling system comprising: a refrigeration circuit; a coolant circuit thermally coupled to the refrigeration circuit; and a free cooling circuit in selective fluid communication with the coolant circuit and in selective thermal communication with the refrigeration circuit.
12 . The cooling system of claim 11 , wherein the refrigeration circuit includes a heat absorbing heat exchanger, the coolant circuit being thermally coupled the refrigeration circuit at the heat absorbing heat exchanger.
13 . The cooling system of claim 12 , wherein both an inlet of the free cooling circuit and an outlet of the free cooling circuit are fluidly connected to the coolant circuit upstream from the heat absorbing heat exchanger.
14 . The cooling system of claim 13 , further comprising at least one valve operable to control a flow of fluid from the coolant circuit to the free cooling circuit.
15 . The cooling system of claim 11 , wherein the refrigeration circuit includes a heat rejecting heat exchanger and the free cooling circuit includes a first heat exchanger positioned directly adjacent to the heat rejecting heat exchanger, the first heat exchanger being arranged in series with the heat rejecting heat exchanger relative to an air flow.
16 . The cooling system of claim 15 , wherein the free cooling circuit includes a subcooler heat exchanger, the free cooling circuit being thermally coupled the refrigeration circuit at the subcooler heat exchanger, wherein the first heat exchanger and the subcooler heat exchanger are arranged in series relative to a flow of fluid within the free cooling circuit.
17 . The cooling system of claim 16 , wherein the free cooling circuit further comprises a first free cooling bypass conduit extending between and fluidly connecting an outlet of the first heat exchanger and an inlet of the subcooler heat exchanger.
18 . The cooling system of claim 17 , wherein the free cooling circuit further comprises a second free cooling bypass conduit extending between and fluidly connecting an outlet of the subcooler heat exchanger and an inlet of the first heat exchanger.
19 . The cooling system of claim 18 , wherein the free cooling circuit further comprises at least one valve operable to fluidly separate the free cooling circuit from the coolant circuit, wherein when the free cooling circuit is fluidly separate from the coolant circuit, the flow of fluid at the outlet of the subcooler heat exchanger is returned directly to the inlet of the first heat exchanger via the second free cooling bypass conduit.
20 . The cooling system of claim 18 , wherein the free cooling circuit further comprises an auxiliary pump to circulate the fluid between the first heat exchanger and the subcooler heat exchanger.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. provisional patent application Ser. No. 63/716,973, filed Nov. 6, 2024, and also claims the benefit of U.S. provisional patent application Ser. No. 63/877,429, filed Sep. 8, 2025, the entire contents of which are incorporated herein by reference. BACKGROUND Exemplary embodiments pertain to cooling systems, and more particularly, to a cooling system capable of performing free cooling. Cooling systems are known for various purposes, such as for cooling of data centers. Such cooling systems can use one or more refrigeration circuits to provide mechanical cooling. It has also been known to supplement or replace mechanical cooling with free cooling, e.g., by cooling of a coolant fluid in heat exchange with outside air. Some systems use a separate free cooling circuit with a low temperature coolant fluid such as glycol, which then exchanges heat with a water circuit that is used for providing cooling within a building, e.g., for a data center. The coils of the free cooling circuit may be arranged directly adjacent to the coils used when a cooling system is operated in a mechanical mode. The coils used to perform free cooling are not activated when the system is operating in the mechanical mode. As a result, the coils used to perform the free cooling create an air side resistance that impacts unit efficiency and capacity when operating in the mechanical mode. BRIEF DESCRIPTION According to an embodiment, a cooling system includes a refrigeration circuit and a coolant circuit for cooling a working fluid to meet a cooling demand. The coolant circuit is thermally coupled to the refrigeration circuit. A free cooling circuit is in selective thermal communication with the refrigeration circuit and is in selective thermal communication with the coolant circuit. In addition to one or more of the features described above, or as an alternative, in further embodiments the refrigeration circuit includes a heat rejection heat exchanger and the free cooling circuit includes a first heat exchanger positioned directly adjacent to the heat rejection heat exchanger. In addition to one or more of the features described above, or as an alternative, in further embodiments a fan is operable to move a flow of air across the first heat exchanger and the heat rejection heat exchanger in series. The first heat exchanger is upstream from the heat rejection heat exchanger relative to the flow of air. In addition to one or more of the features described above, or as an alternative, in further embodiments the free cooling circuit includes a subcooler heat exchanger and the free cooling circuit is thermally coupled to the refrigeration circuit at the subcooler heat exchanger. In addition to one or more of the features described above, or as an alternative, in further embodiments the first heat exchanger and the subcooler heat exchanger are arranged in series relative to a flow of free cooling fluid within the free cooling circuit. In addition to one or more of the features described above, or as an alternative, in further embodiments the subcooler heat exchanger is arranged downstream from the heat rejection heat exchanger relative to a flow of refrigerant circulating through the refrigeration circuit. In addition to one or more of the features described above, or as an alternative, in further embodiments the free cooling circuit includes a main return conduit and a first free cooling bypass conduit arranged in parallel, the first free cooling bypass conduit being fluidly connected to an inlet of the subcooler heat exchanger. In addition to one or more of the features described above, or as an alternative, in further embodiments a second free cooling bypass conduit fluidly connects an outlet of the subcooler heat exchanger to the main return conduit, a valve is disposed within the main return conduit, and another valve is disposed within the second free cooling bypass conduit. In addition to one or more of the features described above, or as an alternative, in further embodiments the inlet of the first free cooling bypass conduit is fluidly connected to the main return conduit upstream from the valve and the outlet of the second free cooling bypass conduit is fluidly connected to the main return conduit downstream from the valve. In addition to one or more of the features described above, or as an alternative, in further embodiments the free cooling circuit includes a second heat exchanger and the free cooling circuit is thermally coupled to the coolant circuit at the second heat exchanger. According to an embodiment, a cooling system includes a refrigeration circuit and a coolant circuit thermally coupled to the refrigeration circuit. A free cooling circuit is arranged in selective fluid communication with the coolant circuit and is arranged in selective thermal communication with the refrigeration circuit. In addition to one or more of the features described a