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EP-4741740-A2 - HYDRONIC FREE COOLING CHILLER WITH SUBCOOLING

EP4741740A2EP 4741740 A2EP4741740 A2EP 4741740A2EP-4741740-A2

Abstract

A cooling system (20) includes a refrigeration circuit (22) and a coolant circuit (40) for cooling a working fluid to meet a cooling demand. The coolant circuit (40) is thermally coupled to the refrigeration circuit (22). A free cooling circuit (50) is in selective thermal communication with the refrigeration circuit (22) and is in selective thermal communication with the coolant circuit (40).

Inventors

  • GRABON, MICHEL
  • GUY, Alexis

Assignees

  • Carrier Corporation

Dates

Publication Date
20260513
Application Date
20251105

Claims (15)

  1. A cooling system (20) comprising: a refrigeration circuit (22); a coolant circuit (40) 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 (50) in selective thermal communication with the refrigeration circuit and in selective thermal communication with the coolant circuit.
  2. The cooling system (20) of claim 1, wherein the refrigeration circuit (22) includes a heat rejection heat exchanger (26) and the free cooling circuit includes a first heat exchanger (52) positioned directly adjacent to the heat rejection heat exchanger, and optionally wherein the cooling system further comprises a fan (58) operable to move a flow of air across the first heat exchanger (52) and the heat rejection heat exchanger (26) in series, the first heat exchanger being upstream from the heat rejection heat exchanger relative to the flow of air.
  3. The cooling system (20) of claim 2, wherein the free cooling circuit (50) includes a subcooler heat exchanger (60) and the free cooling circuit is thermally coupled to the refrigeration circuit (22) at the subcooler heat exchanger.
  4. The cooling system (20) of claim 3, wherein the first heat exchanger (52) and the subcooler heat exchanger (60) are arranged in series relative to a flow of free cooling fluid within the free cooling circuit (50), and/or wherein the subcooler heat exchanger (60) is arranged downstream from the heat rejection heat exchanger (26) relative to a flow of refrigerant circulating through the refrigeration circuit.
  5. The cooling system (20) of claim 3 or 4, wherein the free cooling circuit (50) includes a main return conduit (62) and a first free cooling bypass conduit (64) arranged in parallel, the first free cooling bypass conduit being fluidly connected to an inlet of the subcooler heat exchanger (60).
  6. The cooling system (20) of claim 5, further comprising: a second free cooling bypass conduit (68) fluidly connecting an outlet of the subcooler heat exchanger (60) to the main return conduit (62); a valve disposed within the main return conduit; and another valve disposed within the second free cooling bypass conduit, optionally, wherein the inlet of the first free cooling bypass conduit (64) is fluidly connected to the main return conduit (62) upstream from the valve and the outlet of the second free cooling bypass conduit (68) is fluidly connected to the main return conduit downstream from the valve.
  7. The cooling system (20) of any preceding claim, wherein the free cooling circuit (50) includes a second heat exchanger (54), the free cooling circuit being thermally coupled to the coolant circuit (40) at the second heat exchanger.
  8. A cooling system (220) comprising: a refrigeration circuit (222); a coolant circuit (240) thermally coupled to the refrigeration circuit; and a free cooling circuit (250) in selective fluid communication with the coolant circuit and in selective thermal communication with the refrigeration circuit.
  9. The cooling system (220) of claim 8, wherein the refrigeration circuit (222) includes a heat absorbing heat exchanger (230), the coolant circuit (240) being thermally coupled the refrigeration circuit at the heat absorbing heat exchanger.
  10. The cooling system (220) of claim 9, wherein both an inlet of the free cooling circuit (250) and an outlet of the free cooling circuit are fluidly connected to the coolant circuit (240) upstream from the heat absorbing heat exchanger (230), and optionally wherein the cooling system (220) further comprises at least one valve operable to control a flow of fluid from the coolant circuit (240) to the free cooling circuit (250).
  11. The cooling system (220) of claims 8, 9 or 10, wherein the refrigeration circuit (222) includes a heat rejecting heat exchanger (226) and the free cooling circuit (250) includes a first heat exchanger (252) 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.
  12. The cooling system (220) of claim 11, wherein the free cooling circuit (250) includes a subcooler heat exchanger (260), the free cooling circuit being thermally coupled the refrigeration circuit at the subcooler heat exchanger, wherein the first heat exchanger (252) and the subcooler heat exchanger are arranged in series relative to a flow of fluid within the free cooling circuit.
  13. The cooling system (220) of claim 12, wherein the free cooling circuit (250) further comprises a first free cooling bypass conduit (264) extending between and fluidly connecting an outlet of the first heat exchanger (252) and an inlet of the subcooler heat exchanger (260).
  14. The cooling system (220) of claim 13, wherein the free cooling circuit (250) further comprises a second free cooling bypass conduit (268) extending between and fluidly connecting an outlet of the subcooler heat exchanger (260) and an inlet of the first heat exchanger (252).
  15. The cooling system (220) of claim 14, wherein the free cooling circuit (250) further comprises at least one valve operable to fluidly separate the free cooling circuit from the coolant circuit (240), 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 (260) is returned directly to the inlet of the first heat exchanger (252) via the second free cooling bypass conduit (268), and/or wherein the free cooling circuit (250) further comprises an auxiliary pump (266) to circulate the fluid between the first heat exchanger (252) and the subcooler heat exchanger (260).

Description

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 a first aspect of the invention a cooling system is provided, the 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. Optionally, 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. Optionally, the cooling system comprises 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 may be upstream from the heat rejection heat exchanger relative to the flow of air. Optionally, 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. Optionally, 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. Optionally, the subcooler heat exchanger is arranged downstream from the heat rejection heat exchanger relative to a flow of refrigerant circulating through the refrigeration circuit. Optionally, 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. Optionally, the cooling system comprises: 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. Optionally, 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. Optionally, 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 a second aspect of the invention a cooling system is provided, the 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. Optionally, the refrigeration circuit includes a heat absorbing heat exchanger and the coolant circuit is thermally coupled the refrigeration circuit at the heat absorbing heat exchanger. Optionally, 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. Optionally, at least one valve is operable to control a flow of fluid from the coolant circuit to the free cooling circuit. Optionally, 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 is arranged in series with the heat rejecting heat exchanger relative to an air flow. Optionally, the free cooling circuit includes a subcooler heat exchanger and the free cooling circuit is thermally coupled the refrigeration circuit at the subcooler heat exchanger. The first heat exchanger and the subcooler heat exchanger may be