AIR CONDITIONING SYSTEM WITH ICE STORAGE
An air conditioning system includes a condenser and an evaporator configured to remove thermal energy from a water flow through the evaporator via a refrigerant flow through the evaporator. A refrigerant conduit is configured to convey a refrigerant flow through the evaporator and the condenser. An ice storage tank is fluidly connected to the refrigerant conduit such that the refrigerant flow is flowable through the ice storage tank to transfer thermal energy between the refrigerant flow and a volume of frozen water disposed in the ice storage tank.
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The subject matter disclosed herein relates to air conditioning systems. More specifically, the subject disclosure relates ice storage systems for air conditioning systems.
Ice storage is used in air conditioning systems, for example, chiller systems, to take advantage of the large energy content of a volume of frozen water. A traditional ice storage system for an air conditioning system 100 is shown in
Such a system operates in many different modes depending on cooling requirements. In brine cooling mode, also called vapor compression mode, the chiller 100 operates as a conventional chiller. The valves 116 are closed and/or opened so that the brine flow bypasses the ice storage tank 114 and flows through the evaporator 110. In this mode, the evaporator 110 cools the brine flow to about 7 degrees Celsius and the brine is flowed to a chiller 118 to cool a desired space. When the system 100 is operating in ice storage mode, such as when there is not a need to cool the desired space, the air conditioning system 100 flows the brine not to the chiller 118, but to the ice storage tank 114. During this mode, the brine is cooled to −5 degrees to −10 degrees Celsius by the evaporator 110 and freezes water in the ice storage tank 114 thus storing cooling energy in the ice storage tank 114. During operation of the air conditioning system 100 in ice cooling mode, the refrigerant loop 102 is not operating. Brine is circulated through the ice storage tank 114 to cool the brine flow which is then flowed to the chiller 118 to cool the desired space.
Use of the ice storage tank 114 in conjunction with the chiller 118 allows a size of the chiller 118 and allows the air conditioning system 100 to take advantage of lower nighttime electricity costs by using ice storage mode.
Circulation of brine through the ice storage tank 114, however, reduces thermal efficiency of the air conditioning system 100 versus a system utilizing water routed through the chiller 118, since brine has poor heat transfer characteristics when compared to water. Further, inclusion of the brine loop 112 makes the air conditioning system 100 layout complicated due to the valves 116 and other components required to direct the brine flow through the system when operating in the various modes.
BRIEF DESCRIPTION OF THE INVENTIONAccording to one aspect of the invention, an air conditioning system includes a condenser and an evaporator configured to remove thermal energy from a water flow through the evaporator via a refrigerant flow through the evaporator. A refrigerant conduit is configured to convey a refrigerant flow through the evaporator and the condenser. An ice storage tank is fluidly connected to the refrigerant conduit such that the refrigerant flow is flowable through the ice storage tank to transfer thermal energy between the refrigerant flow and a volume of frozen water disposed in the ice storage tank.
According to another aspect of the invention, a method of operating an air conditioning system includes urging a refrigerant flow along a refrigerant pathway and through a compressor. The refrigerant flow is conveyed through a condenser disposed along the refrigerant pathway and at least a portion of the refrigerant flow is flowed through an ice storage tank via an ice tank pathway. A volume of water disposed in the ice storage tank is frozen via the refrigerant flow thus storing cooling energy in the ice storage tank.
According to yet another aspect of the invention, a method of operating an air conditioning system includes conveying a refrigerant flow through a refrigerant conduit to an ice storage tank, the ice storage tank containing a volume of frozen water therein. Thermal energy is transferred from the refrigerant flow to the volume of frozen water, thereby cooling the refrigerant flow. The refrigerant flow is urged from the ice storage tank to an evaporator and a water flow is conveyed to the evaporator via a water pathway. Thermal energy is transferred from the water flow to the refrigerant flow via the evaporator, thereby cooling the water flow. The water flow is conveyed to a chiller to cool a desired space via the chiller.
These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.
The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.
DETAILED DESCRIPTION OF THE INVENTIONShown in
The air conditioning system 200 operates in a variety of modes depending on cooling requirements of the space 224. Shown in
Illustrated in
The stored cooling energy in the ice storage tank 212 is utilized when the system 200 is operated in ice cooling mode illustrated in
The system 200 can also be operated in a dual water cooling and ice cooling mode. In this mode, as shown in
While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
Claims
1. An air conditioning system comprising:
- a condenser;
- an evaporator configured to remove thermal energy from a water flow through the evaporator via a refrigerant flow through the evaporator;
- a refrigerant conduit configured to convey a refrigerant flow through the evaporator and the condenser; and
- an ice storage tank fluidly connected to the refrigerant conduit such that the refrigerant flow is flowable through the ice storage tank to transfer thermal energy between the refrigerant flow and a volume of frozen water disposed in the ice storage tank.
2. The air conditioning system of claim 1, wherein the ice storage tank is disposed external to a chiller of the air conditioning system.
3. The air conditioning system of claim 1, further comprising a pump configured to urge the refrigerant flow from the ice storage tank to the evaporator.
4. The air conditioning system of claim 1, further comprising an ice tank conduit extending through the ice storage tank configured to convey the refrigerant flow through the ice storage tank.
5. The air conditioning system of claim 4, wherein the ice tank conduit is connected to the refrigerant conduit via one or more valves.
6. The air conditioning system of claim 5, wherein opening the one or more valves allows the refrigerant flow to flow through the ice storage tank.
7. The air conditioning system of claim 1, wherein the water flow is urged from the evaporator to a chiller to cool a desired space.
8. A method of operating an air conditioning system comprising:
- urging a refrigerant flow along a refrigerant pathway and through a compressor;
- conveying the refrigerant flow through a condenser disposed along the refrigerant pathway;
- flowing at least a portion of the refrigerant flow through an ice storage tank via an ice tank pathway; and
- freezing a volume of phase change material disposed in the ice storage tank via the refrigerant flow thus storing cooling energy in the ice storage tank.
9. The method of claim 8, wherein a refrigerant flow temperature is about −3.0 to −7.0 degrees Celsius below a freezing point of the phase change material.
10. The method of claim 8, further comprising opening at least one valve between the refrigerant pathway and the ice tank pathway to allow the refrigerant flow to flow to the ice storage tank.
11. The method of claim 8, further comprising:
- flowing at least a portion of the refrigerant flow from the condenser to an evaporator;
- transferring thermal energy from a water flow to the refrigerant flow thus cooling the water flow, the water flow flowing through the evaporator via a water pathway;
- conveying the water flow to a chiller via the water pathway; and
- cooling a desired space via the chiller.
12. A method of operating an air conditioning system comprises:
- conveying a refrigerant flow through a refrigerant conduit to an ice storage tank, the ice storage tank containing a volume of frozen phase change material therein;
- transferring thermal energy from the refrigerant flow to the volume of frozen phase change material, thereby cooling the refrigerant flow;
- urging the refrigerant flow from the ice storage tank to an evaporator;
- conveying a water flow to the evaporator via a water pathway;
- transferring thermal energy from the water flow to the refrigerant flow via the evaporator, thereby cooling the water flow; and
- conveying the water flow to a chiller to cool a desired space via the chiller.
13. The method of claim 12, wherein a temperature of the ice storage tank is lower than a refrigerant temperature, thus the refrigerant flow is conveyed to the ice storage tank via thermal forces.
14. The method of claim 12, wherein the refrigerant flow is urged from the ice storage tank to the evaporator via a pump.
15. The method of claim 12, wherein the refrigerant flow bypasses a compressor, a condenser, and/or an expansion valve disposed along the refrigerant pathway.
16. The method of claim 12, wherein a refrigerant flow temperature is about −3.0 to −7.0 degrees Celsius below a freezing point of the phase change material.
Type: Application
Filed: Feb 25, 2011
Publication Date: Jun 19, 2014
Applicant: Carrier Corporation (Farmington, CT)
Inventors: Michel Grabon (Bressolles), Didier Da Costa (Lyon)
Application Number: 13/992,549
International Classification: F25C 5/18 (20060101);