阅读说明：本技术 冷却设备、冷却方法和冷却系统 (Cooling apparatus, cooling method, and cooling system ) 是由 查世彤 于 2019-06-06 设计创作，主要内容包括：本公开涉及一种冷却设备、冷却系统和冷却方法。所述冷却设备包括闪蒸箱、中温载荷部、低温载荷部、第一压缩机、第二压缩机和排出器。闪蒸箱存储制冷剂。中温载荷部使用来自闪蒸箱的制冷剂来将中温载荷部附近的空间冷却到第一温度。低温载荷部使用来自闪蒸箱的制冷剂来将低温载荷部附近的空间冷却到第二温度,该第二温度低于该第一温度。第一压缩机压缩来自低温载荷部的制冷剂。第二压缩机压缩来自中温载荷部的制冷剂。在除霜循环期间,排出器将来自第一压缩机的制冷剂和来自第二压缩机的制冷剂的混合物引到低温载荷部。该混合物使该低温载荷部除霜。闪蒸箱接纳该混合物。(The present disclosure relates to a cooling apparatus, a cooling system, and a cooling method. The cooling equipment comprises a flash tank, a medium-temperature load part, a low-temperature load part, a first compressor, a second compressor and an ejector. The flash tank stores refrigerant. The intermediate-temperature load section cools a space near the intermediate-temperature load section to a first temperature using a refrigerant from the flash tank. The low-temperature load portion cools a space near the low-temperature load portion to a second temperature, which is lower than the first temperature, using refrigerant from the flash tank. The first compressor compresses the refrigerant from the low-temperature load portion. The second compressor compresses the refrigerant from the intermediate-temperature load portion. During the defrost cycle, the ejector directs a mixture of refrigerant from the first compressor and refrigerant from the second compressor to the low temperature load portion. The mixture defrosts the low temperature load portion. A flash tank receives the mixture.)

1. A cooling apparatus, comprising:

a flash tank configured to store a refrigerant;

a medium-temperature load section configured to cool a space near the medium-temperature load section to a first temperature using refrigerant from the flash tank;

A low-temperature load portion configured to cool a space near the low-temperature load portion to a second temperature using refrigerant from the flash tank, the second temperature being lower than the first temperature;

A first compressor configured to compress the refrigerant from the low-temperature load portion;

A second compressor configured to compress the refrigerant from the middle temperature load portion; and

An ejector configured to direct a mixture of refrigerant from the first compressor and refrigerant from the second compressor to the low temperature load portion during a defrost cycle, the mixture defrosting the low temperature load portion, the flash tank further configured to receive the mixture.

2. the cooling apparatus of claim 1, further comprising a valve configured to direct a portion of the mixture from the flash tank to the second compressor.

3. The cooling apparatus of claim 1, further comprising a valve configured to direct a portion of the refrigerant from the first compressor to the second compressor when a pressure of the refrigerant from the first compressor exceeds a threshold.

4. The cooling apparatus of claim 1, further comprising a valve configured to direct refrigerant from the second compressor to the ejector during the defrost cycle and to direct refrigerant from the second compressor to a high side heat exchanger after the defrost cycle ends.

5. the cooling apparatus of claim 1, further comprising a second cryogenic load configured to cool a space near the second cryogenic load using refrigerant from the flash tank, the second compressor further configured to compress refrigerant from the second cryogenic load, the ejector further configured to direct the mixture to the second cryogenic load during a second defrost cycle.

6. The cooling apparatus of claim 1, further comprising a valve configured to stop flow of the refrigerant from the flash tank to the low temperature load portion during the defrost cycle.

7. the cooling apparatus of claim 1, wherein the ejector is further configured to direct the mixture to the intermediate temperature load during a third defrost cycle.

8. A method of cooling, the method comprising:

Storing refrigerant with a flash tank;

cooling a space near the intermediate-temperature load part to a first temperature by means of an intermediate-temperature load part using a refrigerant from the flash tank;

Cooling, with a cryogenic load section, a space near the cryogenic load section to a second temperature using refrigerant from the flash tank, the second temperature being lower than the first temperature;

Compressing the refrigerant from the low-temperature load portion by means of a first compressor;

compressing the refrigerant from the intermediate-temperature load portion by means of a second compressor;

introducing a mixture of refrigerant from the first compressor and refrigerant from the second compressor to the low temperature load portion via an ejector during a defrost cycle, the mixture defrosting the low temperature load portion; and

Receiving the mixture via the flash tank.

9. The cooling method of claim 8, further comprising directing a portion of the mixture from the flash tank to the second compressor via a valve.

10. The cooling method of claim 8, further comprising directing a portion of the refrigerant from the first compressor to the second compressor via a valve when a pressure of the refrigerant from the first compressor exceeds a threshold.

11. The cooling method of claim 8, further comprising directing refrigerant from the second compressor to the ejector during the defrost cycle via a valve and directing refrigerant from the second compressor to a high side heat exchanger after the defrost cycle ends.

12. The cooling method of claim 8, further comprising:

Cooling, by a second low-temperature load portion, a space near the second low-temperature load portion using the refrigerant from the flash tank;

Compressing the refrigerant from the second low-temperature load portion by the second compressor; and

During a second defrost cycle, directing the mixture to the second low temperature load with the ejector.

13. The cooling method according to claim 8, further comprising stopping a flow of the refrigerant from the flash tank to the low temperature load portion by means of a valve during the defrost cycle.

14. The cooling method of claim 8, further comprising directing the mixture to the intermediate temperature load portion via the ejector during a third defrost cycle.

15. A cooling system, the cooling system comprising:

A high-side heat exchanger configured to remove heat from a refrigerant;

a flash tank configured to store refrigerant from the high-side heat exchanger;

A medium-temperature load section configured to cool a space near the medium-temperature load section to a first temperature using refrigerant from the flash tank;

A low-temperature load portion configured to cool a space near the low-temperature load portion to a second temperature using refrigerant from the flash tank, the second temperature being lower than the first temperature;

a first compressor configured to compress the refrigerant from the low temperature load portion;

A second compressor configured to compress the refrigerant from the middle temperature load portion; and

An ejector configured to direct a mixture of refrigerant from the first compressor and refrigerant from the second compressor to the low temperature load portion during a defrost cycle, the mixture defrosting the low temperature load portion, the flash tank further configured to receive the mixture.

16. The cooling system of claim 15, further comprising a valve configured to direct a portion of the mixture from the flash tank to the second compressor.

17. The cooling system of claim 15, further comprising a valve configured to direct a portion of the refrigerant from the first compressor to the second compressor when a pressure of the refrigerant from the first compressor exceeds a threshold.

18. The cooling system of claim 15, further comprising a valve configured to direct refrigerant from the second compressor to the ejector during the defrost cycle and to direct refrigerant from the second compressor to the high side heat exchanger after the defrost cycle ends.

19. The cooling system of claim 15, further comprising a second cryogenic load configured to cool a space near the second cryogenic load using refrigerant from the flash tank, the second compressor further configured to compress refrigerant from the second cryogenic load, the ejector further configured to direct the mixture to the second cryogenic load during a second defrost cycle.

20. the cooling system of claim 15, further comprising a valve configured to stop the flow of refrigerant from the flash tank to the low temperature load portion during the defrost cycle.

21. The cooling system of claim 15, wherein the ejector is further configured to direct the mixture to the medium temperature load during a third defrost cycle.

Technical Field

The present disclosure generally relates to a cooling system.

Background

The cooling system may circulate a refrigerant to cool various spaces. For example, a refrigeration system may circulate a refrigerant to cool a space near or around a refrigerated load. After the refrigerant absorbs heat, the refrigerant may be circulated back to the refrigeration load to defrost the refrigeration load.

disclosure of Invention

The cooling system circulates a refrigerant to cool various spaces. For example, refrigeration systems circulate a refrigerant to cool a space near or around a refrigerated load. These load portions include metal components (such as coils) that carry the refrigerant. As the refrigerant passes through these metal parts, frost and/or ice may accumulate on the exterior of these metal parts. The ice and/or frost reduces the efficiency of the load portion. For example, as frost and/or ice accumulates on the load portion, the refrigerant within the load portion may become more difficult to absorb heat outside the load portion. Typically, ice and frost accumulate on the load in the low temperature portion of the system (e.g., the freezer).

In prior systems, one way to address frost and/or ice accumulation on the load portion is to circulate the refrigerant back to the load portion after the refrigerant has absorbed heat from the load portion. Typically, the discharge from the cryogenic compressor is recycled back to the cryogenic load to defrost the load. In this way, the heated refrigerant passes through frost and/or ice accretion and defrosts the load portion. This process of circulating hot refrigerant through a frosted and/or iced load is referred to as hot gas defrost. Existing cooling systems with hot gas defrost cycles use a stepper valve and large piping at the discharge of the cryogenic compressor to regulate the pressure of the hot gas used to defrost the load section. These components take up space and increase the footprint of the cooling system.

The present disclosure contemplates a refrigeration system that can perform hot gas defrost without having to use a stepper valve at the cryogenic compressor discharge to increase the pressure of the hot gas used to defrost the load section. The cooling system directs refrigerant at the medium temperature compressor discharge to the load section to defrost the load section. In this manner, the cost and footprint of the system is reduced in certain embodiments. Certain embodiments of the cooling system are described below.

According to one embodiment, there is provided a cooling apparatus including a flash tank, a medium temperature load section, a low temperature load section, a first compressor, a second compressor, and an ejector. The flash tank stores refrigerant. The intermediate-temperature load section cools a space near the intermediate-temperature load section to a first temperature using a refrigerant from the flash tank. The low-temperature load portion cools a space near the low-temperature load portion to a second temperature, which is lower than the first temperature, using refrigerant from the flash tank. The first compressor compresses the refrigerant from the low-temperature load portion. The second compressor compresses the refrigerant from the intermediate-temperature load portion. The ejector directs a mixture of refrigerant from the first compressor and refrigerant from the second compressor to the low temperature load portion during a defrost cycle. The mixture defrosts the low temperature load portion. A flash tank receives the mixture.

According to another embodiment, there is provided a cooling method including: storing refrigerant with a flash tank; and cooling the space near the intermediate-temperature load part to a first temperature by means of the intermediate-temperature load part using the refrigerant from the flash tank. The method further comprises the following steps: cooling a space near the low temperature load portion to a second temperature using refrigerant from the flash tank by the low temperature load portion, the second temperature being lower than the first temperature; and compressing the refrigerant from the low-temperature load portion by means of the first compressor. The method further comprises the following steps: compressing the refrigerant from the intermediate-temperature load portion by a second compressor; and introducing a mixture of the refrigerant from the first compressor and the refrigerant from the second compressor to the low-temperature load portion via the ejector during the defrost cycle. The mixture defrosts the low temperature load portion. The method also includes receiving the mixture through a flash tank.

according to yet another embodiment, a cooling system is provided that includes a high side heat exchanger, a flash tank, a medium temperature load, a low temperature load, a first compressor, a second compressor, and an ejector. The high side heat exchanger removes heat from the refrigerant. The flash tank stores refrigerant. The intermediate-temperature load section cools a space near the intermediate-temperature load section to a first temperature using a refrigerant from the flash tank. The low-temperature load portion cools a space near the low-temperature load portion to a second temperature, which is lower than the first temperature, using refrigerant from the flash tank. The first compressor compresses the refrigerant from the low-temperature load portion. The second compressor compresses the refrigerant from the intermediate-temperature load portion. The ejector directs a mixture of refrigerant from the first compressor and refrigerant from the second compressor to the low temperature load portion during a defrost cycle. The mixture defrosts the low temperature load portion. A flash tank receives the mixture.

Certain embodiments may provide one or more technical advantages. For example, one embodiment reduces the size of the piping used in existing cooling systems. As another example, an embodiment eliminates a stepper valve for an existing cooling system. As yet another example, an embodiment reduces the amount of refrigerant in the cooling system and reduces the energy used by the cooling system. Some embodiments may include none, some, or all of the above technical advantages. One or more other technical advantages may be readily apparent to one skilled in the art from the figures, descriptions, and claims included herein.

drawings

for a more complete understanding of this disclosure, reference is now made to the following descriptions taken in conjunction with the accompanying drawing, in which:

FIG. 1 illustrates an example cooling system;

FIG. 2 illustrates an example cooling system; and is

FIG. 3 is a flow chart illustrating a method of operating the example cooling system of FIG. 2.

Detailed Description

embodiments of the present disclosure and its advantages are best understood by referring to figures 1 through 3 of the drawings, like numerals being used for like and corresponding parts of the various drawings.

The cooling system circulates a refrigerant to cool various spaces. For example, refrigeration systems circulate a refrigerant to cool a space near or around a refrigerated load. These load portions include metal components (such as coils) that carry the refrigerant. As the refrigerant passes through these metal parts, frost and/or ice may accumulate on the exterior of these metal parts. The ice and/or frost reduces the efficiency of the load portion. For example, as frost and/or ice accumulates on the load portion, the refrigerant within the load portion may become more difficult to absorb heat outside the load portion. Typically, ice and frost accumulate on the load in the low temperature portion of the system (e.g., the freezer).

in prior systems, one way to address frost and/or ice buildup on the load portion is to circulate the refrigerant back to the load portion after the refrigerant has absorbed heat from the load portion. Typically, the discharge from the cryogenic compressor is recycled back to the cryogenic load to defrost the load. In this way, the heated refrigerant passes through frost and/or ice accretion and defrosts the load portion. This process of circulating hot refrigerant through a frosted and/or iced load is referred to as hot gas defrost.

Existing cooling systems with hot gas defrost cycles use a stepper valve to establish the discharge pressure for hot gas defrost. For example, a stepper valve may increase the pressure of the refrigerant from 28 bar to 40 bar. After the hot gas is used to defrost the load, the gas is pumped to a flash tank, which typically stores refrigerant at 36 bar. A small pressure differential between the hot gas supply and the flash tank (e.g., 40-36 bar-4 bar) results in the need for large piping to limit the pressure drop across the hot gas/refrigerant lines. If the pressure drop across the hot gas/refrigerant is too great, the pressure at the flash tank may catch up with the pressure at the stepper valve and the flow of hot gas may reverse and/or stop. Large piping increases the material cost of the refrigeration system and it increases the amount of space occupied by the refrigeration system.

the present disclosure contemplates a refrigeration system that can perform hot gas defrost without having to use a stepper valve at the cryogenic compressor discharge to increase the pressure of the hot gas used to defrost the load section. The cooling system directs refrigerant at the medium temperature compressor discharge to the load section to defrost the load section. In this manner, the cost and footprint of the system is reduced in certain embodiments. In some embodiments, the cooling system reduces the amount of refrigerant in the cooling system and reduces the energy used by the cooling system. The cooling system will be described using fig. 1 to 3. Fig. 1 will describe an existing cooling system with hot gas defrost. Fig. 2 and 3 depict a cooling system with improved hot gas defrost.

FIG. 1 illustrates an example cooling system 100. As shown in fig. 1, system 100 includes high side heat exchanger 105, flash tank 110, medium temperature load section 115, low temperature load section 120, medium temperature compressor 125, low temperature compressor 130, and valve 135. By operating the valve 135, the system 100 allows hot gas to circulate to the low temperature load portion 120 to defrost the low temperature load portion 120. After defrosting the low temperature load 120, hot gas and/or refrigerant is circulated back to the flash tank 110.

The high-side heat exchanger 105 removes heat from the refrigerant. As heat is removed from the refrigerant, the refrigerant is cooled. The present disclosure contemplates the high side heat exchanger 105 operating as a condenser, a fluid cooler, and/or a gas cooler. When operating as a condenser, the high-side heat exchanger 105 cools the refrigerant so that the state of the refrigerant changes from gas to liquid. When operating as a fluid cooler, the high side heat exchanger 105 cools the liquid refrigerant and the refrigerant remains liquid. When operating as a gas cooler, the high-side heat exchanger 105 cools the gaseous refrigerant and the refrigerant remains as a gas. In some configurations, the high-side heat exchanger 105 is arranged so that the heat removed from the refrigerant can be discharged into the air. For example, the high-side heat exchanger 105 may be disposed on a roof so that heat removed from the refrigerant may be discharged into the air. As another example, the high-side heat exchanger 105 may be arranged outside the building and/or on a side of the building.

The flash tank 110 stores the refrigerant received from the high-side heat exchanger 105. The present disclosure contemplates a flash tank 110 that stores refrigerant in any state, such as, for example, liquid and/or gaseous. The refrigerant leaving the flash tank 110 is supplied to the low temperature load portion 120 and the medium temperature load portion 115. In some embodiments, flash gas and/or gaseous refrigerant is released from flash tank 110. By releasing the flash gas, the pressure within flash tank 110 may be reduced.

The system 100 includes a low temperature portion and a medium temperature portion. The low temperature section operates at a lower temperature than the medium temperature section. In some refrigeration systems, the low temperature portion may be a refrigeration system and the medium temperature system may be a conventional refrigeration system. In a grocery store setting, the low temperature portion may include a freezer for holding frozen food items, and the medium temperature portion may include a refrigerated shelf for holding products. The refrigerant flows from the flash tank 110 to the low and medium temperature portions of the refrigeration system. For example, the refrigerant flows to the low temperature load portion 120 and the medium temperature load portion 115. When the refrigerant reaches low temperature load portion 120 or medium temperature load portion 115, the refrigerant removes heat from the air around low temperature load portion 120 or medium temperature load portion 115. As a result, the air is cooled. The cooled air may then be circulated, such as, for example, by a fan, to cool a space, such as, for example, a freezer and/or a refrigerated shelf. As the refrigerant passes through the low temperature load portion 120 and the medium temperature load portion 115, the refrigerant may change from a liquid state to a gaseous state as it absorbs heat.

When the refrigerant passes through low temperature load portion 120 and medium temperature load portion 115, the refrigerant cools the metal components of low temperature load portion 120 and medium temperature load portion 115. For example, the metal coils, plates, components of the low and medium temperature load portions 120, 115 may cool as the refrigerant passes through them. The components may become so cold that the vapors in the air outside of the components condense and eventually freeze or frost onto the components. As ice or frost accumulates on these metal components, the refrigerant in these components may become more difficult to absorb heat from the air outside of these components. In essence, frost and ice act as a thermal barrier. As a result, the more ice and frost that accumulates, the more the efficiency of the cooling system 100 decreases. The cooling system 100 may use the heated refrigerant to defrost these metal components.

The refrigerant flows from the low temperature load portion 120 and the medium temperature load portion 115 to the compressors 125 and 130. The present disclosure contemplates a system 100 that includes any number of cryogenic compressors 130 and intermediate temperature compressors 125. The low temperature compressor 130 and the middle temperature compressor 125 compress the refrigerant to increase the pressure of the refrigerant. As a result, heat in the refrigerant may become concentrated and the refrigerant may become a high-pressure gas. The low temperature compressor 130 compresses the refrigerant from the low temperature load part 120 and transmits the compressed refrigerant to the medium temperature compressor 125. The medium temperature compressor 125 compresses a mixture of refrigerants from the low temperature compressor 130 and the medium temperature load part 115. The medium temperature compressor 125 then sends the compressed refrigerant to the high side heat exchanger 105.

The valve 135 may be opened or closed to circulate the refrigerant from the low temperature compressor 130 back to the low temperature load portion 120. The refrigerant may be heated after absorbing heat from the low temperature load part 120 and compressed by the low temperature compressor 130. The hot refrigerant and/or hot gas is then circulated through the metal components of the low temperature load portion 120 to defrost those components. Thereafter, the hot gas and/or refrigerant is circulated back to flash tank 110.

Valve 135 comprises a step valve that increases the pressure of the hot gas and/or refrigerant so that it can be cycled back to low temperature load portion 120 to defrost low temperature load portion 120. For example, the stepper valve may increase the pressure of the hot gas and/or refrigerant from 28 bar to 40 bar. A stepper valve is required so that the pressure of the hot gas and/or refrigerant can be increased above the pressure of flash tank 110 (e.g., the pressure of flash tank 110 can be 36 bar). In this manner, the hot gas and/or refrigerant may be at a sufficiently high pressure to be circulated back into flash tank 110.

In this example, the pressure difference between the hot gas and/or refrigerant and flash tank 110 may be about 4 bar, as the stepper valve increases the pressure of the refrigerant to 40 bar and flash tank 110 is maintained at 36 bar. This 4 bar pressure differential is small and results in the system 100 requiring large piping to limit the pressure drop of the hot gas and/or refrigerant as it defrosts the cryogenic load 120 and then travels to the flash tank 110. If the pressure drop across the hot gas and/or refrigerant lines is too great, the pressure at the flash tank 110 may overcome the pressure at the stepper valve and the flow of hot gas and/or refrigerant may reverse and/or stop. The large piping results in increased cost and larger footprint for the system 100.

The present disclosure contemplates a cooling system that can perform hot gas defrost without having to use a stepper valve and/or large piping to regulate the pressure of the hot gas. The system uses refrigerant at the discharge of the medium temperature compressor to perform hot gas defrost. In this manner, the cost and/or footprint of the cooling system is reduced in certain embodiments. An embodiment of the cooling system is described below using fig. 2 and 3.

FIG. 2 illustrates an example cooling system 200. As shown in fig. 2, the system 200 includes a high side heat exchanger 105, a flash tank 110, a medium temperature load section 115, low temperature load sections 120A and 120B, a medium temperature compressor 125, a low temperature compressor 130, valves 205, 210, and 215, a valve 220, a valve 225, an ejector 230, valves 235, 240, and 245, a valve 250, and a controller 255. The system 200 can perform hot gas defrost on one or more of the medium temperature load 115, the low temperature load 120A, and the low temperature load 120B without the use of stepper valves. In this manner, in certain embodiments, the system 200 has a reduced cost and/or footprint relative to existing systems.

Generally, the high side heat exchanger 105, flash tank 110, medium temperature load section 115, low temperature load section 120A, low temperature load section 120B, medium temperature compressor 125, and low temperature compressor 130 operate similarly as they do in the system 100. For example, the high-side heat exchanger 105 removes heat from the refrigerant. The flash tank 110 stores refrigerant. The medium temperature load portion 115, the low temperature load portion 120A, and the low temperature load portion 120B cool the space near these load portions using a refrigerant. The low temperature compressor 130 compresses the refrigerant from the low temperature load portions 120A and 120B. The medium temperature compressor 125 compresses the refrigerant from the medium temperature load portion 115. These components operate together to cool the space near the load portion.

Between flash tank 110, medium temperature load section 115, low temperature load section 120A, and low temperature load section 120B, system 200 includes valves 205, 210, and 215. Valves 205, 210, and 215 control the flow of refrigerant from flash tank 110 to medium temperature load portion 115, low temperature load portion 120A, and low temperature load portion 120B. For example, when valve 205 is open, refrigerant flows from flash tank 110 to medium temperature load portion 115. When the valve 205 is closed, the refrigerant from the flash tank 110 cannot flow to the medium-temperature load portion 115. As another example, when valve 210 is open, refrigerant from flash tank 110 can flow to low temperature load portion 120A. When the valve 210 is closed, the refrigerant from the flash tank 110 cannot flow to the low temperature load portion 120A. As yet another example, when valve 215 is open, refrigerant from flash tank 110 can flow to low temperature load portion 120B. When the valve 215 is closed, the refrigerant from the flash tank 110 cannot flow to the low temperature load portion 120B.

One or more of valves 205, 210, and 215 may be opened when one or more of medium temperature load portion 115, low temperature load portion 120A, and low temperature load portion 120B is operating. One or more of valves 205, 210, and 215 may be closed when one or more of medium temperature load portion 115, low temperature load portion 120A, and low temperature load portion 120B is not operating. For example, when the mid-temperature load portion 115, the low-temperature load portion 120A, and/or the low-temperature load portion 120B are in a defrost cycle, their respective valves 205, 210, and 215 are closed. After the defrost cycle is complete, one or more of valves 205, 210, and 215 may be reopened to continue operation of medium temperature load portion 115, low temperature load portion 120A, and/or low temperature load portion 120B.

the valves 205, 210, and 215 are used to cool the refrigerant entering the load portions 115, 120A, and 120B. Valves 205, 210, and 215 may receive refrigerant from any component of system 200, such as, for example, high side heat exchanger 105 and/or flash tank 110. Valves 205, 210, and 215 reduce the pressure and therefore the temperature of the refrigerant. Valves 205, 210, and 215 reduce the pressure of the refrigerant from the inflow valves 205, 210, and 215. The temperature of the refrigerant may then decrease as the pressure decreases. As a result, the refrigerant entering valves 205, 210, and 215 may be cooler when exiting valves 205, 210, and 215. The refrigerant leaving the valve 205 is supplied to the load portion 115. The refrigerant leaving valve 210 is supplied to load portion 120A. The refrigerant leaving the valve 215 is supplied to the load portion 120B.

Valve 220, valve 225, drain 230, valve 235, valve 240, and valve 245 control one or more defrost cycles of system 200. During each defrost cycle, one or more of the medium temperature load portion 115, the low temperature load portion 120A, and the low temperature load portion 120B are defrosted. The mixture of hot gases discharged from the intermediate temperature compressor 125 and the low temperature compressor 130 is directed to the load section being defrosted. The mixture defrosts the load and is directed back to flash tank 110. In this manner, in certain embodiments, one or more defrost cycles may be performed without the use of a stepper valve.

Valve 220 controls the flow of refrigerant between the low temperature compressor 130 and the medium temperature compressor 125. In certain embodiments, the valve 220 is a check valve that allows refrigerant to flow from the low temperature compressor 130 to the medium temperature compressor 125 if the pressure of the refrigerant exceeds a threshold value. The threshold may be an internal pressure threshold of the valve 220. When the pressure of the refrigerant does not exceed the threshold value, the valve 220 prevents the refrigerant from flowing from the low temperature compressor 130 to the medium temperature compressor 125. Alternatively, the refrigerant flows from the low temperature compressor 130 to the ejector 230. When the pressure of the refrigerant exceeds the internal pressure threshold of the valve 220, the valve 220 opens and a portion of the refrigerant from the low temperature compressor 130 flows to the medium temperature compressor 125. Even if the valve 220 is opened, a portion of the refrigerant from the low temperature compressor 130 may continue to flow to the ejector 230.

valve 225 controls the flow of refrigerant from the medium temperature compressor 125. In certain embodiments, valve 225 is a three-way valve. Valve 225 receives refrigerant from the intermediate temperature compressor 125. The valve 225 then directs the refrigerant to either the high side heat exchanger 105 or the ejector 230. During the defrost cycle, valve 225 directs refrigerant to drain 230. After the defrost cycle is complete, the valve 225 directs the refrigerant to the high side heat exchanger 105. In certain embodiments, the valve 225 may direct a portion of the refrigerant to the ejector 230 and a portion to the high side heat exchanger 105.

during the defrost cycle, the ejector 230 directs a mixture of refrigerant from the low temperature compressor 130 and refrigerant from the medium temperature compressor 125 to valves 235, 240, and/or 245. In certain embodiments, the ejector 230 recovers the throttling energy, reducing the process of ejecting the boost. As previously discussed, this process increases the pressure of some of the refrigerant from the cryogenic compressor 130 so that the refrigerant can flow to the flash tank 110.

Valves 235, 240, and 245 control the flow of hot gases to the medium temperature load section 115, low temperature load section 120A, and low temperature load section 120B. During the defrost cycle, one or more of valves 235, 240, and 245 are opened to allow hot gas to flow to one or more of medium temperature load 115, low temperature load 120A, and low temperature load 120B. For example, during the first defrost cycle, valve 235 may be opened to allow hot gas flow from ejector 230 to low temperature load portion 120B. The hot gases defrost the low temperature load section 120B and flow to the flash tank 110. After the first defrost cycle is complete, valve 235 may be closed to prevent hot gas flow to low temperature load portion 120B. During the second defrost cycle, valve 240 may be opened to allow hot gas from ejector 230 to flow to low temperature load portion 120A. The hot gases defrost the low temperature load section 120A and flow to the flash tank 110. After the second defrost cycle is complete, the valve 240 may be closed to prevent hot gas flow to the low temperature load portion 120A. During the third defrost cycle, valve 245 is opened to allow hot gas to flow from the ejector 230 to the medium temperature load 115. The hot gas defrosts the medium temperature load 115 and flows to flash tank 110. After the first defrost cycle is complete, the valve 245 may be closed to prevent hot gas flow to the medium temperature load section 115.

As previously mentioned, when a defrost cycle is performed on a load, the corresponding valve 205, 210, or 215 for that load is closed to prevent refrigerant from flowing from the flash tank 110 to that load. Using the foregoing example, during the first defrost cycle, valve 215 may be closed to prevent refrigerant from flowing from flash tank 110 to low temperature load 120B. During the second defrost cycle, valve 210 may be closed to prevent refrigerant from flowing from flash tank 110 to low temperature load portion 120A. During the third defrost cycle, valve 205 may be closed to prevent refrigerant from flowing from flash tank 110 to medium temperature load 115.

Flash tank 110 receives hot gas for defrosting the load section. Flash tank 110 may discharge the hot gases along with the flash gas in flash tank 110. Valve 250 controls the flow of flash gas and/or hot gas from flash tank 110 and thus controls the internal pressure of flash tank 110. When the valve 250 is opened more, it increases the flow of hot and/or flash gas from the flash tank 110 to the medium temperature compressor 125 and the flash tank pressure decreases. When valve 250 is open less, it reduces the flow of flash gas and/or hot gas, which may cause the flash tank pressure to increase. The intermediate temperature compressor 125 compresses the flash gas and/or hot gas and directs the compressed hot gas and/or flash gas to a valve 225.

Controller 255 includes a processor 260 and a memory 265. The present disclosure contemplates that processor 260 and memory 265 are configured to perform the functions of controller 255 as described herein. Generally, the controller 255 controls the valves 205, 210, 225, 235, 240, and 245 to control one or more defrost cycles.

processor 260 is any electronic circuit including, but not limited to, a microprocessor, an Application Specific Integrated Circuit (ASIC), an application specific instruction set processor (ASIP), and/or a state machine that is communicatively connected to memory 265 and controls the operation of controller 255. Processor 260 may be 8-bit, 16-bit, 32-bit, 64-bit, or any other suitable architecture. Processor 260 may include: an Arithmetic Logic Unit (ALU) to perform arithmetic and logical operations; a processor register that supplies operands to the ALU and stores a result of the ALU operation; and a control unit that fetches instructions from memory and executes them by directing the coordinated operation of the ALUs, registers, and other components. Processor 260 may include other hardware and software for controlling and processing information. Processor 260 executes software stored on memory 265 to perform any of the functions described herein. Processor 260 controls the operation and management of controller 255 by processing information received from the various components of system 200. Processor 260 may be a programmable logic device, a microcontroller, a microprocessor, any suitable processing device, or any suitable combination of the preceding. Processor 260 is not limited to a single processing device and may include multiple processing devices.

Memory 265 may store data, operating software, or other information for processor 260, either permanently or temporarily. Memory 265 may include any one or combination of volatile or non-volatile local or remote devices suitable for storing information. For example, memory 265 may include Random Access Memory (RAM), Read Only Memory (ROM), magnetic storage devices, optical storage devices, or any other suitable information storage device or combination of devices. The software represents any suitable set of instructions, logic, or code embodied in a computer-readable storage medium. For example, the software may be embodied in the memory 265, a magnetic disk, an optical disk, or a flash drive. In particular embodiments, the software may include applications that may be executed by processor 260 to perform one or more of the functions of controller 255 as described herein.

in certain embodiments, the controller 255 determines when to activate a defrost cycle. Controller 255 may make this determination based on any suitable criteria. For example, the controller 255 may activate a defrost cycle when it determines that a sufficient amount of ice and/or frost has accumulated on the load portion. As another example, the controller 255 may activate a defrost cycle based on a timer such that the load portion periodically undergoes a defrost cycle. The controller 255 may use any number of temperature sensors, pressure sensors, moisture/humidity sensors, ice/frost sensors, and/or timers to determine when to activate the defrost cycle.

For example, the controller 255 may use a temperature sensor, a moisture/humidity sensor, or an ice/frost sensor to determine that ice or frost has accumulated on the low-temperature load portion 120A. In response, the controller 255 closes the valve 210 and adjusts the valve 225 to direct the refrigerant to the ejector 230. Controller 255 then opens valve 240 such that exhaust from ejector 230 flows to low temperature load portion 120A. The discharge defrosts the low temperature load 120A and flows to the flash tank 110. After the defrost cycle is completed, the controller 255 closes the valve 240 and adjusts the valve 225 to introduce the refrigerant to the high side heat exchanger 105. The controller 255 then opens the valve 210 so that the low temperature load portion 120A can resume operation. The controller 255 performs a similar process to defrost the middle temperature load part 115 and the low temperature load part 120B.

In this manner, the system 200 performs hot gas defrost without having to use a stepper valve. As a result, in certain embodiments, the system 200 uses less energy and/or less refrigerant than existing systems that perform hot gas defrost. As a result, the cost and footprint of the system 200 is reduced in some embodiments.

The present disclosure may relate to refrigerant from particular components of the system 200 (e.g., refrigerant from a medium temperature compressor, refrigerant from a low temperature compressor, refrigerant from a flash tank, etc.). When such terms are used, the disclosure does not limit the refrigerant described to coming directly from a particular component. The present disclosure contemplates that the refrigerant comes from a particular component (e.g., a medium temperature compressor), even though other intervening components may exist between the particular component and the destination of the refrigerant. For example, the intermediate temperature load portion receives refrigerant from the flash tank even if an expansion valve is present between the flash tank and the intermediate temperature load portion.

FIG. 3 is a flow chart illustrating a method 300 of operating the example cooling system 200 of FIG. 2. In particular embodiments, various components of system 200 perform the steps of method 300. In this manner, in some embodiments, the amount of energy and/or refrigerant in the cooling system is reduced. Additionally, in certain embodiments, the cost and footprint of the system is reduced.

The high side heat exchanger begins to remove heat from the refrigerant in step 305. In step 310, the flash tank stores the refrigerant. In step 315, the middle temperature load part cools the first space using the refrigerant. In step 320, the low temperature load portion cools the second space using the refrigerant. In step 325, the cryogenic compressor compresses a refrigerant for cooling the second space. In step 330, the medium temperature compressor compresses a refrigerant for cooling the first space.

in step 335, it is determined whether a hot gas defrost cycle should be activated. In some embodiments, a controller comprising a hardware processor and memory performs step 335. For example, the controller may detect whether ice and/or frost is accumulated on the load portion. The controller may activate a defrost cycle if the controller determines that ice and/or frost is accumulated on the load portion. The controller may determine not to activate the defrost cycle if the controller determines that ice and/or frost is not accumulated on the load portion or if an insufficient amount of ice or frost is accumulated on the load portion. In step 340, if the controller determines that the defrost cycle should not be activated, the medium temperature compressor compresses the compressed refrigerant for cooling the second space. The refrigerant may then be directed to a high side heat exchanger.

If the controller determines that the defrost cycle should be activated, the ejector directs a mixture of compressed refrigerant used to cool the first space and compressed refrigerant used to cool the second space to a load (such as, for example, a low temperature load) used to cool the second space. The mixture then defrosts the load portion. In step 350, the mixture is directed to a flash tank after it has been used to defrost the load portion.

Modifications, additions, or omissions may be made to method 300 depicted in fig. 3. The method 300 may include more, fewer, or other steps. For example, the steps may be performed in parallel or in any suitable order. Although discussed as system 200 (or components thereof) performing this step, any suitable component of system 200 may perform one or more steps of the method.

modifications, additions, or omissions may be made to the systems and devices described herein without departing from the scope of the disclosure. The components of the system and apparatus may be integral or separate. Further, the operations of the system and apparatus may be performed by more, fewer, or other components. Additionally, the operations of the systems and devices may be performed using any suitable logic comprising software, hardware, and/or other logic. As used in this document, "each" refers to each member of a group or each member of a subgroup of a group.

While the present disclosure includes several embodiments, a myriad of changes, variations, alterations, transformations, and modifications may be suggested to one skilled in the art, and it is intended that the present disclosure encompass such changes, variations, alterations, transformations, and modifications as fall within the scope of the appended claims.