EP4653781A1

EP4653781A1 - Water chiller thermal storage

Info

Publication number: EP4653781A1
Application number: EP25177337.0A
Authority: EP
Inventors: Vishnu Sishtla; Jin Zhu
Original assignee: Carrier Corp
Current assignee: Carrier Corp
Priority date: 2024-05-21
Filing date: 2025-05-19
Publication date: 2025-11-26
Also published as: CN120991490A; US20250362060A1

Abstract

A chiller system (20) includes a compressor (22), a condenser (28), an expansion device (32), and an evaporator (30) operably coupled to form a closed fluid loop having a fluid circulating therethrough. A flow of a cooling fluid (W) is arranged in a heat transfer relationship with the fluid at the condenser. An energy transfer device is located downstream from the condenser relative to the flow of the cooling fluid. The energy transfer device is arranged in fluid communication with a third fluid (C) and at least a portion of the heat from the fluid is transferred to the third fluid at the energy transfer device.

Description

BACKGROUND

Exemplary embodiments of the present disclosure relate to the art of condensers, and more particularly, to a water chiller system having various means for removing heat from the water of the water chiller system.
Chiller refrigeration systems are known and include a heat exchanger where refrigerant of the system is cooled and condensed by an external water flow. The heat removed from the refrigerant by the external water flow is then exhausted or dumped outside of the system at a cooling tower. Such a system makes an inefficient use of this heat. It is therefore desirable to repurpose the heat removed at the condenser to improve the overall efficiency of the system.

BRIEF DESCRIPTION

According to an aspect, there is provided a chiller system including a compressor, a condenser, an expansion device, and an evaporator operably coupled to form a closed fluid loop having a fluid circulating therethrough. A flow of a cooling fluid is arranged in a heat transfer relationship with the fluid at the condenser. An energy transfer device is located downstream from the condenser relative to the flow of the cooling fluid. The energy transfer device is arranged in fluid communication with a third fluid and at least a portion of the heat from the fluid is transferred to the third fluid at the energy transfer device.
The energy transfer device may be a thermal storage device containing a phase change material.
The phase change material may be selected from ice, wax, and salt.
Optionally, the energy transfer device is a heat exchanger and the cooling fluid and the third fluid are arranged in a heat transfer relationship at the heat exchanger.
Optionally, a bypass conduit is arranged in parallel with the energy transfer device.
Optionally, a valve is operable to control a flow of the cooling fluid through the bypass conduit to achieve a demanded temperature downstream from the energy transfer device.
The condenser and the energy transfer device may be part of a second closed loop through which the cooling fluid is configured to circulate.
A pump may be provided for moving the cooling fluid through the second closed loop.
A cooling tower may contain cooling fluid. Optionally, the cooling tower is arranged in fluid communication with the condenser and a fan operable to move another fluid across the cooling tower to remove heat from the cooling fluid.
Optionally, a component for further heating the third fluid is arranged at a location downstream from an outlet of the energy transfer device.
The third fluid may be water and the downstream component may be a water heater.
The chiller system may be a water-cooled chiller system.
According to an aspect, there is provided a method of operating a chiller system including circulating a fluid through a closed loop including a compressor, a condenser, an expansion device, and an evaporator, removing heat from the fluid within the closed loop via a cooling fluid, and transferring at least a portion of the heat removed from the fluid to a third fluid at an energy transfer device.
Optionally, the condenser and the energy transfer device are part of a second closed loop through which the cooling fluid is configured to circulate. Optionally, the cooling fluid provided at an outlet of the energy transfer device is returned to the condenser.
The method may comprise cooling the cooling fluid provided at the outlet of the energy transfer device prior to returning the cooling fluid to the condenser.
Cooling the cooling fluid provided at the outlet of the energy transfer device may include moving an external gas across the cooling fluid via at least one fan at a cooling tower to remove heat from the cooling fluid.
The method may comprise heating the third fluid to a demanded temperature at a component.
The component may be located downstream from an outlet of the energy transfer device.
The chiller system may be a water-cooled chiller system.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:

FIG. 1 is a schematic diagram of an existing water-cooled chiller system;
FIG. 2 is a schematic diagram of a water-cooled chiller system including an energy transfer device; and
FIG. 3 is a schematic diagram of another water-cooled chiller system including an energy transfer device.

DETAILED DESCRIPTION

A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.
With reference now to FIG. 1, an example of an existing vapor compression system 20, and more particularly a chiller system, having a closed fluid loop within which a refrigerant R or other fluid circulates is provided. As shown, the vapor compression system 20 includes a compressor 22 having a suction port (inlet) 24 and a discharge port (outlet) 26. The vapor compression system 20 further includes a first, heat rejection heat exchanger 28, for example a condenser. The vapor compression system 20 additionally includes a second, heat absorption heat exchanger 30, for example an evaporator, located downstream from the heat rejection heat exchanger 28. Further, an expansion device 32 is located along the fluid flow path downstream of the compressor 22 and upstream of the evaporator heat absorption heat exchanger. As shown, the expansion device 32 may be located at a position along the fluid loop between the heat rejection heat exchanger 28 and the heat absorption heat exchanger 30.
At the heat rejection heat exchanger 28, the refrigerant is arranged in a thermal or heat transfer relationship with a cooling fluid W. In the illustrated-non-limiting embodiment, the cooling fluid W is water. Accordingly, the heat rejection heat exchanger 28 may be a refrigerant-water heat exchanger where the refrigerant is cooled by an external flow of water. In such embodiments, the vapor compression system of FIG. 1 may be referred to herein as a water-cooled chiller. The flow of cooling fluid W may be delivered from a source 36, such as a cooling tower for example, located directly adjacent to the heat rejection heat exchanger 28, or alternatively, located remotely from the heat rejection heat exchanger 28, such as at a different location within a building being conditioned by the vapor compression system 20 for example. As shown, a pump 38 may be used to circulate a flow of cool cooling fluid W from the cooling tower 36 to the heat rejection heat exchanger 28 and also to return a flow of heated cooling fluid W to the cooling tower 36 from the heat rejection heat exchanger 28. Within the cooling tower 36, the cooling fluid W may be cooled via a flow of an external gas driven by at least one fan 40, such as an airflow for example, before being returned to the heat rejection heat exchanger 28. Although the cooling fluid W is illustrated and described herein water, it should be understood that any other suitable fluid may be used as the cooling fluid W.
With reference now to FIGS. 2 and 3, the heat removed from the vapor compression system 20 by the flow of cooling fluid W may be repurposed via an energy transfer device as will be described in more detail below. In an embodiment, shown in FIG. 2, the energy transfer device includes at least one thermal storage device 50 disposed along the closed loop defining the flow path of the cooling fluid W. Although only a single thermal storage device 50 is illustrated and described herein, it should be appreciated that in other embodiments, the vapor compression system 20 may include a plurality of thermal storage devices arranged in parallel or in series relative to the flow of cooling fluid W. In the illustrated, non-limiting embodiment, the thermal storage device 50 is arranged downstream from the heat rejection heat exchanger 28 and upstream from the cooling tower 36, such as directly downstream from the heat rejection heat exchanger 28 for example. However, embodiments where the thermal storage device 50 is arranged at another location within the closed loop defining the flow path of the cooling fluid W are also contemplated herein.
In an embodiment, the thermal storage device 50 is filled with a phase change material P, such as wax, salt, or water for example. However, any suitable phase change material P is contemplated herein. The phase change material P within the thermal storage device 50 may function as a heat sink. As previously noted, the cooling fluid W output from the heat rejection heat exchanger 28 is hot. In operation, from the outlet of the heat rejection heat exchanger 28, all or at least a portion of the cooling fluid W is provided to the thermal storage device 50. The cooling fluid W may be configured to pass over or flow across the thermal storage device 50, or alternatively, or in addition, may flow through one or more passages that extend through the body of phase change material P within the thermal storage device 50. In embodiments where the phase change material P is a cool material, heat from the cooling fluid W is transferred to the phase change material. Over time, this heat may, but need not, cause the phase change material P to change phases, such as from a solid to a liquid, or from a liquid to a gas for example. As a result of this heat absorption, the cooling fluid W provided at the outlet 54 of the thermal storage device 50 is cooler than the cooling fluid W provided at the inlet 52 of the thermal storage device 50. The at least partially cooled cooling fluid W may then be provided to the cooling tower 36 where further heat may be removed from the cooling fluid W is needed, such as via a flow of an external gas driven by the fan 40 for example. The cooled cooling fluid W is then returned to the heat rejection heat exchanger to repeat the cycle.
As shown, a bypass conduit 60 may extend from a location upstream from the inlet 52 of the thermal storage device 50 to a location downstream from the outlet 54 of the thermal storage device 50. A valve V may be arranged within the bypass conduit 60 to control a flow therethrough. A portion of the cooling fluid W may be allowed to flow through the bypass conduit 60 to achieve a warmer temperature downstream from the thermal storage device 50 than if all of the cooling fluid were provided to the thermal storage device 50.
As shown, a third fluid C may be arranged in thermal communication with the thermal storage device 50. In an embodiment, the third fluid C is another fluid associated with the building being conditioned by the vapor compression system 20. For example, the third fluid C may be a flow of water provided from a water source and to be delivered to a downstream component 70, such as a water heater or boiler. However, it should be understood that any suitable third fluid that is typically heated before being delivered to a load of the building is also within the scope of the disclosure.
As shown, the third fluid C delivered to the thermal storage device 50 may be arranged in a heat transfer relationship with the phase change material P at the thermal storage device 50. More specifically, the third fluid C is operable as a heat sink and removes heat from the phase change material P. Accordingly, the flow of the third fluid C output from the thermal storage device 50 is heated relative to the flow of the third fluid C provided to the thermal storage device 50. From the thermal storage device 50, the heated third fluid C may be provided to the downstream water heater, illustrated schematically at 70, before being delivered to a load of the building. The temperature of the third fluid C provided to the water heater 70 from the thermal storage device 50 is warmer than if the third fluid C had been provided directly from the water source to the water heater 70. Accordingly, the heat and energy required to heat the third fluid C at the water heater 70 to a demanded temperature is less when the third fluid has been at least partially preheated via the thermal storage device 50.
With reference now to FIG. 3, in other embodiments, the energy transfer device includes a heat exchanger 80 disposed along the closed loop defining the flow path of the cooling fluid W such that the cooling fluid W may be cooled at the heat exchanger 80. In the illustrated, non-limiting embodiment, the heat exchanger 80 is arranged downstream from the heat rejection heat exchanger 28 and upstream from the cooling tower 36, such as directly downstream from the heat rejection heat exchanger 28 for example. However, embodiments where the heat exchanger 80 is arranged at another location within the closed loop defining the flow path of the water are also contemplated herein. Further, it should be understood that a heat exchanger having any suitable configuration is contemplated herein.
Similar to the previous embodiment, a bypass conduit 60 may extend from a location upstream from an inlet 82 of the heat exchanger 80 to a location downstream from an outlet 84 of the heat exchanger 80. A valve V may be arranged within the bypass conduit 60 to control a flow therethrough. A portion of the cooling fluid W may be allowed to flow through the bypass conduit 60 to achieve a warmer temperature downstream from the heat exchanger 80 than if all of the cooling fluid W were provided to the heat exchanger 80.
The cooling fluid W is arranged in a thermal heat transfer relationship with the third fluid C at the heat exchanger 80. As previously described, the third fluid C may be another fluid associated with the building being conditioned by the vapor compression system 20, such as water for example. The heat exchanger 80 may be located downstream from a source of the third fluid C and upstream from a component operable to heat the third fluid C prior to being delivered to a load of the building.
All or at least a portion of the hot cooling fluid W output from the heat rejection heat exchanger 28 is provided to a first flow path of the heat exchanger 80 via a first inlet 82. Simultaneously, a flow of the third fluid C is provided to a second flow path of the heat exchanger 80 via a second inlet 86. As both fluids W, C move through the heat exchanger 80, the third fluid C functions as a heat sink and absorbs heat from the cooling fluid W. Accordingly, the cooling fluid W provided at the first outlet 84 of the heat exchanger 80 is cooler than the cooling fluid provided to the first inlet 82 of the heat exchanger 80. The at least partially cooled cooling fluid W may then be provided to the cooling tower 36 where further heat may be removed therefrom, such as via a flow of an external gas driven by the fan 40 for example. The cooled cooling fluid W is then returned to the heat rejection heat exchanger to repeat the cycle.
The third fluid C provided at the second outlet 88 of the heat exchanger 80 is hotter than the third fluid C provided at the second inlet 86 of the heat exchanger 80. This heated third fluid C may be provided to the downstream water heater 70, illustrated schematically at 70. The temperature of the third fluid C provided to the water heater 70 from the heat exchanger 80 is warmer than if the third fluid C had been provided directly from the water source to the water heater 70. Accordingly, the heat and energy required to heat the third fluid C at the water heater 70 to a demanded temperature is reduced when the third fluid has been at least partially preheated via the heat exchanger 80.
Redirecting the heat removed from a refrigerant at a heat rejection heat exchanger to another fluid that is being heated reduces the overall energy, and therefore the cost, associated with heating the fluid.
The term "about" is intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and/or groups thereof.
While the present disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims.

Claims

A chiller system (20) comprising:
a compressor (22), a condenser (28), an expansion device (32), and an evaporator (30) operably coupled to form a closed fluid loop having a fluid circulating therethrough;

a flow of a cooling fluid (W) arranged in a heat transfer relationship with the fluid at the condenser; and

an energy transfer device located downstream from the condenser relative to the flow of the cooling fluid, the energy transfer device being arranged in fluid communication with a third fluid (C), wherein at least a portion of the heat from the fluid is transferred to the third fluid at the energy transfer device.
The chiller system (20) of claim 1, wherein the energy transfer device is a thermal storage device (50) containing a phase change material (P).
The chiller system (20) of claim 2, wherein the phase change material (P) is selected from ice, wax, and salt.
The chiller system (20) of claim 1, wherein the energy transfer device is a heat exchanger (80), the cooling fluid (W) and the third fluid (C) being arranged in a heat transfer relationship at the heat exchanger.
The chiller system (20) of any of claims 1-4, further comprising a bypass conduit (60) arranged in parallel with the energy transfer device, optionally wherein the chiller system comprises a valve (V) operable to control a flow of the cooling fluid through the bypass conduit to achieve a demanded temperature downstream from the energy transfer device.
The chiller system (20) any of claims 1-5, wherein the condenser (28) and the energy transfer device are part of a second closed loop through which the cooling fluid (W) is configured to circulate, optionally wherein the chiller system comprises a pump (38) for moving the cooling fluid through the second closed loop.
The chiller system (20) of any of claims 1-6, further comprising a cooling tower (36) containing the cooling fluid (W), the cooling tower being arranged in fluid communication with the condenser (28) and a fan (40) operable to move another fluid across the cooling tower to remove heat from the cooling fluid.
The chiller system (20) of any of claims 1-7, further comprising a component (70) for further heating the third fluid (C) arranged at a location downstream from an outlet of the energy transfer device.
The chiller system (20) of any of claims 1-8, wherein the third fluid (C) is water and the downstream component (70) is a water heater.
The chiller system (20) of any of claims 1-9, wherein the chiller system is a water-cooled chiller system.
A method of operating a chiller system (20) comprising:
circulating a fluid through a closed loop including a compressor (22), a condenser (28), an expansion device (32), and an evaporator (30);

removing heat from the fluid within the closed loop via a cooling fluid (W); and

transferring at least a portion of the heat removed from the fluid to a third fluid (C) at an energy transfer device.
The method of claim 11, wherein the condenser (28) and the energy transfer device are part of a second closed loop through which the cooling fluid (W) is configured to circulate, the method further comprising returning the cooling fluid provided at an outlet (54; 84) of the energy transfer device to the condenser.
The method of claim 12, further comprising further cooling the cooling fluid (W) provided at the outlet (54; 84) of the energy transfer device prior to returning the cooling fluid to the condenser (28),
optionally wherein the further cooling the cooling fluid (W) provided at the outlet (54; 84) of the energy transfer device includes moving an external gas across the cooling fluid via at least one fan (40) at a cooling tower (36) to remove heat from the cooling fluid.
The method of any of claims 11-13, further comprising further heating the third fluid (C) to a demanded temperature at a component (70), optionally wherein the component is located downstream from an outlet of the energy transfer device.
The method of any of claims 11-14, wherein the chiller system is a water-cooled chiller system.