Water Chiller Thermal Storage

This application claims the benefit of U.S. provisional patent application Ser. No. 63/650,126, filed May 21, 2024, the entire contents of which are incorporated herein by reference.

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.

According to an embodiment, a chiller system includes 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.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments the energy transfer device is a thermal storage device containing a phase change material.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments the phase change material is selected from ice, wax, and salt.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, 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.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, a bypass conduit is arranged in parallel with the energy transfer device.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, 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.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the condenser and the energy transfer device are part of a second closed loop through which the cooling fluid is configured to circulate.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, a pump is provided for moving the cooling fluid through the second closed loop.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, a cooling tower contains cooling fluid. 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.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, a component for further heating the third fluid is arranged at a location downstream from an outlet of the energy transfer device.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the third fluid is water and the downstream component is a water heater.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the chiller system is a water-cooled chiller system.

According to an embodiment, a method of operating a chiller system includes 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.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the condenser and the energy transfer device are part of a second closed loop through which the cooling fluid is configured to circulate. The cooling fluid provided at an outlet of the energy transfer device is returned to the condenser.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, cooling the cooling fluid provided at the outlet of the energy transfer device prior to returning the cooling fluid to the condenser.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, cooling the cooling fluid provided at the outlet of the energy transfer device includes moving an external gas across the cooling fluid via at least one fan at a cooling tower to remove heat from the cooling fluid.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, further heating the third fluid to a demanded temperature at a component.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the component is located downstream from an outlet of the energy transfer device.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the chiller system is a water-cooled chiller system.

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, an example of an existing vapor compression system, 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 systemincludes a compressorhaving a suction port (inlet)and a discharge port (outlet). The vapor compression systemfurther includes a first, heat rejection heat exchanger, for example a condenser. The vapor compression systemadditionally includes a second, heat absorption heat exchanger, for example an evaporator, located downstream from the heat rejection heat exchanger. Further, an expansion deviceis located along the fluid flow path downstream of the compressorand upstream of the evaporator heat absorption heat exchanger. As shown, the expansion devicemay be located at a position along the fluid loop between the heat rejection heat exchangerand the heat absorption heat exchanger.

At the heat rejection heat exchanger, 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 exchangermay be a refrigerant-water heat exchanger where the refrigerant is cooled by an external flow of water. In such embodiments, the vapor compression system ofmay be referred to herein as a water-cooled chiller. The flow of cooling fluid W may be delivered from a source, such as a cooling tower for example, located directly adjacent to the heat rejection heat exchanger, or alternatively, located remotely from the heat rejection heat exchanger, such as at a different location within a building being conditioned by the vapor compression systemfor example. As shown, a pumpmay be used to circulate a flow of cool cooling fluid W from the cooling towerto the heat rejection heat exchangerand also to return a flow of heated cooling fluid W to the cooling towerfrom the heat rejection heat exchanger. Within the cooling tower, the cooling fluid W may be cooled via a flow of an external gas driven by at least one fan, such as an airflow for example, before being returned to the heat rejection heat exchanger. 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, the heat removed from the vapor compression systemby 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, the energy transfer device includes at least one thermal storage devicedisposed along the closed loop defining the flow path of the cooling fluid W. Although only a single thermal storage deviceis illustrated and described herein, it should be appreciated that in other embodiments, the vapor compression systemmay 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 deviceis arranged downstream from the heat rejection heat exchangerand upstream from the cooling tower, such as directly downstream from the heat rejection heat exchangerfor example. However, embodiments where the thermal storage deviceis 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 deviceis 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 devicemay function as a heat sink. As previously noted, the cooling fluid W output from the heat rejection heat exchangeris hot. In operation, from the outlet of the heat rejection heat exchanger, all or at least a portion of the cooling fluid W is provided to the thermal storage device. The cooling fluid W may be configured to pass over or flow across the thermal storage device, 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. 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 outletof the thermal storage deviceis cooler than the cooling fluid W provided at the inletof the thermal storage device. The at least partially cooled cooling fluid W may then be provided to the cooling towerwhere further heat may be removed from the cooling fluid W is needed, such as via a flow of an external gas driven by the fanfor example. The cooled cooling fluid W is then returned to the heat rejection heat exchanger to repeat the cycle.

As shown, a bypass conduitmay extend from a location upstream from the inletof the thermal storage deviceto a location downstream from the outletof the thermal storage device. A valve V may be arranged within the bypass conduitto control a flow therethrough. A portion of the cooling fluid W may be allowed to flow through the bypass conduitto achieve a warmer temperature downstream from the thermal storage devicethan if all of the cooling fluid were provided to the thermal storage device.

As shown, a third fluid C may be arranged in thermal communication with the thermal storage device. In an embodiment, the third fluid C is another fluid associated with the building being conditioned by the vapor compression system. 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, 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 devicemay be arranged in a heat transfer relationship with the phase change material P at the thermal storage device. 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 deviceis heated relative to the flow of the third fluid C provided to the thermal storage device. From the thermal storage device, the heated third fluid C may be provided to the downstream water heater, illustrated schematically at, before being delivered to a load of the building. The temperature of the third fluid C provided to the water heaterfrom the thermal storage deviceis warmer than if the third fluid C had been provided directly from the water source to the water heater. Accordingly, the heat and energy required to heat the third fluid C at the water heaterto a demanded temperature is less when the third fluid has been at least partially preheated via the thermal storage device.

With reference now to, in other embodiments, the energy transfer device includes a heat exchangerdisposed 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. In the illustrated, non-limiting embodiment, the heat exchangeris arranged downstream from the heat rejection heat exchangerand upstream from the cooling tower, such as directly downstream from the heat rejection heat exchangerfor example. However, embodiments where the heat exchangeris 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 conduitmay extend from a location upstream from an inletof the heat exchangerto a location downstream from an outletof the heat exchanger. A valve V may be arranged within the bypass conduitto control a flow therethrough. A portion of the cooling fluid W may be allowed to flow through the bypass conduitto achieve a warmer temperature downstream from the heat exchangerthan if all of the cooling fluid W were provided to the heat exchanger.

The cooling fluid W is arranged in a thermal heat transfer relationship with the third fluid C at the heat exchanger. As previously described, the third fluid C may be another fluid associated with the building being conditioned by the vapor compression system, such as water for example. The heat exchangermay 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 exchangeris provided to a first flow path of the heat exchangervia a first inlet. Simultaneously, a flow of the third fluid C is provided to a second flow path of the heat exchangervia a second inlet. As both fluids W, C move through the heat exchanger, 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 outletof the heat exchangeris cooler than the cooling fluid provided to the first inletof the heat exchanger. The at least partially cooled cooling fluid W may then be provided to the cooling towerwhere further heat may be removed therefrom, such as via a flow of an external gas driven by the fanfor 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 outletof the heat exchangeris hotter than the third fluid C provided at the second inletof the heat exchanger. This heated third fluid C may be provided to the downstream water heater, illustrated schematically at. The temperature of the third fluid C provided to the water heaterfrom the heat exchangeris warmer than if the third fluid C had been provided directly from the water source to the water heater. Accordingly, the heat and energy required to heat the third fluid C at the water heaterto a demanded temperature is reduced when the third fluid has been at least partially preheated via the heat exchanger.

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.