CN111226080A

CN111226080A - System and method for cleaning a chiller system

Info

Publication number: CN111226080A
Application number: CN201880067201.XA
Authority: CN
Inventors: 马克克雷·威廉·蒙泰思; 杰伊·艾伯特·科勒; 大卫·安德鲁·布雷萧; 安德鲁·迈克尔·韦尔奇
Original assignee: Johnson Controls Technology Co
Current assignee: Johnson Controls Technology Co
Priority date: 2017-08-23
Filing date: 2018-08-23
Publication date: 2020-06-02
Also published as: JP2020531785A; KR20200041961A; EP3673216A1; WO2019040768A1; US20200355413A1; JP2022009384A; KR20220011794A

Abstract

The present disclosure relates to a heating, ventilation, air conditioning and refrigeration (HVAC & R) system (14) including a refrigerant loop and a purge system (80) configured to purge the HVAC & R system of non-condensable gases. The cleaning system includes: a liquid pump (84) configured to draw a first refrigerant flow from an evaporator (38); a controllable expansion valve (86) configured to receive the first refrigerant stream from the liquid pump and reduce a temperature of the first refrigerant stream; and a purge heat exchanger (88) including a purge coil (108). The purge coil is configured to receive the first refrigerant stream from the controllable expansion valve, the chamber of the purge heat exchanger is configured to draw a mixture of the non-condensable gas and a second refrigerant stream from a condenser (34), and the purge heat exchanger is configured to separate the non-condensable gas from the second refrigerant stream using the first refrigerant stream.

Description

System and method for cleaning a chiller system

Background

The present application relates generally to washing systems for air conditioning and refrigeration applications.

Chiller systems or vapor compression systems utilize a working fluid, such as a refrigerant, that changes phase between vapor, liquid, and combinations thereof in response to exposure to different temperatures and pressures associated with operation of the vapor compression system. In a low pressure chiller system, some components of the low pressure chiller system operate at a lower pressure than the surrounding atmosphere. Due to the pressure differential, non-condensable gases (NCG), such as ambient air, may migrate into these low pressure components, which may cause the low pressure cooler system to be inefficient. Thus, the low pressure chiller system can be purged of NCG for more efficient operation. However, conventional cleaning systems for removing NCGs can be costly, require excessive maintenance, and can be inefficient.

Disclosure of Invention

In an embodiment of the present disclosure, a heating, ventilation, air conditioning and refrigeration (HVAC & R) system includes: a refrigerant loop; a compressor disposed along the refrigerant loop; an evaporator disposed along the refrigerant loop; and a condenser disposed along the refrigerant loop. The compressor is configured to circulate a refrigerant through the refrigerant loop, the evaporator is configured to place the refrigerant in heat exchange relationship with a first cooling fluid, and the condenser is configured to place the refrigerant in heat exchange relationship with a second cooling fluid. The HVAC & R system also includes a purging system configured to purge the HVAC & R system of non-condensable gases (NCGs). The cleaning system includes: a liquid pump configured to draw a first flow of refrigerant from the evaporator; a controllable expansion device configured to receive the first refrigerant stream from the liquid pump and reduce a temperature of the first refrigerant stream; and cleaning the heat exchanger. The purge heat exchanger includes a purge coil. The purge coil is configured to receive the first refrigerant stream from the controllable expansion device, the chamber of the purge heat exchanger is configured to draw a mixture comprising the non-condensable gas and a second refrigerant stream from the condenser, and the purge heat exchanger is configured to separate the non-condensable gas in the mixture from the second refrigerant stream in the mixture using the first refrigerant stream.

In another embodiment of the present disclosure, a heating, ventilation, air conditioning and refrigeration (HVAC & R) system includes: a refrigerant loop; a compressor disposed along the refrigerant loop; an evaporator disposed along the refrigerant loop; and a condenser disposed along the refrigerant loop. The compressor is configured to circulate a refrigerant through the refrigerant loop, the evaporator is configured to place the refrigerant in heat exchange relationship with a first cooling fluid, and the condenser is configured to place the refrigerant in heat exchange relationship with a second cooling fluid. The HVAC & R system also includes a purging system configured to purge the HVAC & R system of non-condensable gases (NCGs). The purge system includes a purge heat exchanger configured to separate a mixture drawn from the condenser using a first refrigerant stream of the refrigerant drawn from the evaporator. The mixture includes the NCG from the condenser and a second refrigerant stream of the refrigerant. Separating the mixture comprises separating the NCG from the second refrigerant stream. The washing system also includes one or more thermoelectric assemblies configured to remove thermal energy from the second refrigerant stream.

In another embodiment of the present disclosure, a heating, ventilation, air conditioning and refrigeration (HVAC & R) system includes: a refrigerant loop; a compressor disposed along the refrigerant loop; an evaporator disposed along the refrigerant loop; and a condenser disposed along the refrigerant loop. The compressor is configured to circulate a refrigerant through the refrigerant loop, the evaporator is configured to place the refrigerant in heat exchange relationship with a first cooling fluid, and the condenser is configured to place the refrigerant in heat exchange relationship with a second cooling fluid. The HVAC & R system also includes a purging system configured to purge the HVAC & R system of non-condensable gases (NCGs). The cleaning system includes one or more adsorption chambers configured to receive a mixture including the refrigerant and the NCG from the condenser and configured to separate the refrigerant from the NCG. The cleaning system also includes a pump configured to draw the mixture from the condenser.

In yet another embodiment of the present disclosure, a heating, ventilation, air conditioning and refrigeration (HVAC & R) system includes a purge system configured to purge a vapor compression system of non-condensable gases (NCGs). The purge system includes a pump configured to draw a mixture of vapor refrigerant and the NCG from a condenser of the vapor compression system. The purge system further includes a purge heat exchanger configured to receive the mixture from the pump and place the mixture in heat exchange relationship with a flow of refrigerant drawn from the vapor compression system to condense the vapor refrigerant in the mixture and separate the NCG from the vapor refrigerant in the mixture. The pump is configured to increase the pressure of the mixture to cause the NCG to flow from the purge heat exchanger to atmosphere via a pressure differential between the NCG and atmosphere.

Drawings

FIG. 1 is a perspective view of an embodiment of a building in a commercial environment that may utilize a heating, ventilation, air conditioning and refrigeration (HVAC & R) system in accordance with an aspect of the present disclosure;

FIG. 2 is a perspective view of an embodiment of an HVAC & R system according to one aspect of the present disclosure;

FIG. 3 is a schematic diagram of an embodiment of the HVAC & R system of FIG. 2, according to an aspect of the present disclosure;

FIG. 4 is a schematic diagram of an embodiment of the HVAC & R system of FIG. 2, according to an aspect of the present disclosure;

FIG. 5 is a schematic diagram of an embodiment of the HVAC & R system of FIG. 2, according to an aspect of the present disclosure;

FIG. 6 is a schematic diagram of an embodiment of the HVAC & R system of FIG. 2, according to an aspect of the present disclosure;

FIG. 7 is a schematic diagram of an embodiment of the HVAC & R system of FIG. 2, according to an aspect of the present disclosure;

FIG. 8 is a schematic diagram of an embodiment of the HVAC & R system of FIG. 2, according to an aspect of the present disclosure; and is

FIG. 9 is a schematic diagram of an embodiment of the HVAC & R system of FIG. 2, according to an aspect of the present disclosure.

Detailed Description

Embodiments of the present disclosure include a washing system that may improve washing efficiency in heating, ventilation, air conditioning, and refrigeration (HVAC & R) systems. For example, in certain low pressure HVAC & R systems, the evaporator may draw in non-condensable gases (NCGs), such as ambient air from the atmosphere, due to the pressure differential between the evaporator and the atmosphere. The NCG may travel through the HVAC & R system and eventually collect within the condenser. The NCG may be detrimental to the overall performance of the HVAC & R system and should therefore be removed. Thus, the presently disclosed embodiments may effectively purge the HVAC & R system of NCGs. To this end, the HVAC & R system may include a purge system that may direct a first refrigerant flow from the evaporator to the additional heat exchanger and then separate the NCG with the first refrigerant flow from a second refrigerant flow of the HVAC & R system that may have accumulated within the condenser by condensing the second refrigerant flow to separate the NCG from the second refrigerant flow. Thereafter, the NCG may be pumped or otherwise released to the atmosphere. Additionally or in the alternative, the purging system may utilize one or more other systems in addition to the additional heat exchanger for purging the HVAC & R system of NCGs. For example, the cleaning system may also utilize one or more thermoelectric assemblies and/or adsorption chambers. In particular, the one or more thermoelectric assemblies may help to reduce the temperature of the refrigerant directed from the evaporator, thereby helping the heat exchange process within the additional heat exchanger. Additionally, the one or more adsorption chambers may filter refrigerant from the NCG by utilizing an adsorbent material having an electrochemical affinity for the refrigerant that will adsorb the refrigerant and allow the NCG to flow from the HVAC & R system. Additionally, in certain embodiments, the purge system may utilize a vapor pump to draw the NCG and the second refrigerant stream from the condenser and deliver the NCG and the second refrigerant stream to the additional heat exchanger. That is, the vapor pump may increase its pressure as the NCG and second refrigerant stream are delivered to the additional heat exchanger. Due to the higher pressure, the second refrigerant flow may condense at a higher temperature in the additional heat exchanger, thereby reducing the load on the washing system.

Turning now to the drawings, FIG. 1 is a perspective view of an embodiment of an environment for a heating, ventilation, air conditioning and refrigeration (HVAC & R) system 10 in a building 12 for a typical commercial environment. HVAC & R system 10 may include a vapor compression system 14 that supplies a cooling liquid that may be used to cool building 12. The HVAC & R system 10 may also include a boiler 16 for supplying warm liquid to heat the building 12, and an air distribution system that circulates air through the building 12. The air distribution system may also include an air return duct 18, an air supply duct 20, and/or an air handler 22. In some embodiments, the air handler 22 may include a heat exchanger connected to the boiler 16 and the vapor compression system 14 by a conduit 24. The heat exchanger in the air handler 22 may receive heated liquid from the boiler 16 or cooled liquid from the vapor compression system 14, depending on the mode of operation of the HVAC & R system 10. The HVAC & R system 10 is shown with a separate air handler on each floor of the building 12, but in other embodiments the HVAC & R system 10 may include an air handler 22 and/or other components that may be shared between two or more floors.

Fig. 2 and 3 are embodiments of a vapor compression system 14 that may be used in the HVAC & R system 10. The vapor compression system 14 may circulate refrigerant through a circuit beginning with a compressor 32. The circuit may also include a condenser 34, an expansion valve or device 36, and a liquid cooler or evaporator 38. Vapor compression system 14 can further include a control panel 40 (e.g., a controller) having an analog-to-digital (a/D) converter 42, a microprocessor 44, a non-volatile memory 46, and/or an interface board 48.

Some examples of fluids that may be used as refrigerants in vapor compression system 14 are Hydrofluorocarbon (HFC) -based refrigerants (e.g., R-410A, R-407, R-134a, Hydrofluoroolefins (HFO)), "natural" refrigerants (like ammonia (NH)₃) R-717, carbon dioxide (CO)₂) R-744), or a hydrocarbon-based refrigerant, water vapor, a refrigerant having a low Global Warming Potential (GWP), or any other suitable refrigerant. In some embodiments, the vapor compression system 14 may be configured to efficiently utilize a refrigerant having a normal boiling point at one atmosphere pressure of about 0 degrees celsius or 32 degrees fahrenheit or above, also referred to as a low pressure refrigerant relative to a medium pressure refrigerant such as R-134a or a high pressure refrigerant such as R-410A. As used herein, "normal boiling point" may refer to the boiling point temperature measured at one atmosphere of pressure。

In some embodiments, vapor compression system 14 may use one or more of a Variable Speed Drive (VSD)52, a motor 50, a compressor 32, a condenser 34, an expansion valve or device 36, and/or an evaporator 38. The motor 50 can drive the compressor 32 and can be powered by a Variable Speed Drive (VSD) 52. In certain embodiments, the compressor 32 may utilize magnetic bearings. The VSD52 receives Alternating Current (AC) power having a particular fixed line voltage and fixed line frequency from an AC power source and provides power having a variable voltage and frequency to the motor 50. In other embodiments, the motor 50 may be powered directly by an AC or Direct Current (DC) power source. The motor 50 may include any type of motor that may be powered by a VSD or directly from an AC or DC power source, such as a switched reluctance motor, an induction motor, an electronically commutated permanent magnet motor, or another suitable motor.

The compressor 32 compresses a refrigerant vapor and delivers the vapor to the condenser 34 through a discharge passage. In some embodiments, the compressor 32 may be a centrifugal compressor. The refrigerant vapor delivered by the compressor 32 to the condenser 34 may transfer heat to a cooling fluid (e.g., water or air) in the condenser 34. The refrigerant vapor may condense to a refrigerant liquid in the condenser 34 due to heat transfer with the cooling fluid. Refrigerant liquid from the condenser 34 may flow through an expansion device 36 to an evaporator 38. In the embodiment illustrated in fig. 3, the condenser 34 is water cooled and includes a tube bundle 54 connected to a cooling tower 56 that supplies a cooling fluid to the condenser.

The refrigerant liquid delivered to the evaporator 38 may absorb heat from another cooling fluid, which may or may not be the same cooling fluid used in the condenser 34. The refrigerant liquid in the evaporator 38 may undergo a phase change from refrigerant liquid to refrigerant vapor. As shown in the illustrated embodiment of fig. 3, the evaporator 38 may include a tube bundle 58 having a supply line 60S and a return line 60R connected to a cooling load 62. A cooling fluid (e.g., water, ethylene glycol, calcium chloride brine, sodium chloride brine, or any other suitable fluid) of the evaporator 38 enters the evaporator 38 via a return line 60R and exits the evaporator 38 via a supply line 60S. Evaporator 38 may reduce the temperature of the cooling fluid in tube bundle 58 via heat transfer with a refrigerant. The tube bundle 58 in the evaporator 38 can include a plurality of tubes and/or a plurality of tube bundles. In any event, the refrigerant vapor exits the evaporator 38 and returns to the compressor 32 through a suction line to complete the cycle.

Fig. 4 is a schematic diagram of the vapor compression system 14 with an intermediate circuit 64 coupled between the condenser 34 and the expansion device 36. The intermediate circuit 64 may have an inlet line 68 fluidly connected directly to the condenser 34. In other embodiments, the inlet line 68 may be indirectly fluidly connected to the condenser 34. As shown in the illustrated embodiment of fig. 4, the inlet line 68 includes a first expansion device 66 positioned upstream of an intermediate vessel 70. In some embodiments, the intermediate vessel 70 may be a flash tank (e.g., a flash intercooler). In other embodiments, the intermediate vessel 70 may be configured as a heat exchanger or "surface economizer". In the illustrated embodiment of fig. 4, the intermediate vessel 70 functions as a flash tank, and the first expansion device 66 is configured to reduce the pressure of (e.g., expand) the refrigerant liquid received from the condenser 34. During the expansion process, a portion of the liquid may evaporate, and thus, the intermediate container 70 may be used to separate the vapor from the liquid received from the first expansion device 66. Additionally, the intermediate container 70 may provide for further expansion of the refrigerant liquid as the refrigerant liquid experiences a pressure drop upon entering the intermediate container 70 (e.g., due to a rapid increase in volume upon entering the intermediate container 70). Vapor in the intermediate vessel 70 may be drawn by the compressor 32 through a suction line 74 of the compressor 32. In other embodiments, the vapor in the intermediate vessel may be drawn to an intermediate stage (e.g., not a suction stage) of the compressor 32. The liquid collected in the intermediate container 70 may be at a lower enthalpy than the refrigerant liquid exiting the condenser 34 due to expansion in the expansion device 66 and/or the intermediate container 70. Liquid from the intermediate vessel 70 may then flow into line 72 through the second expansion device 36 to the evaporator 38.

In some embodiments, the evaporator 38 may function at a pressure lower than ambient pressure when the vapor compression system 14 is in operation. Thus, the NCG may be drawn into the evaporator 38 and move through the compressor 32 to accumulate in the condenser 34. These NCGs may cause the vapor compression system 14 to operate inefficiently. Accordingly, the vapor compression system 14 may include features for purging the vapor compression system 14 of NCGs.

For example, as seen in fig. 5, the vapor compression system 14 may include a purge system 80. The purge system 80 is configured to remove NCG (such as ambient air) from the vapor compression system 14 by utilizing refrigerant from the vapor compression system 14. To this end, in certain embodiments, the purge system 80 may include a flash tank 82, a liquid pump 84, a controllable expansion device 86, a purge heat exchanger 88, a pump 90 (e.g., a vacuum pump and/or a vapor pump), an ejector 94, and one or more shut-off valves 96, such as solenoid valves.

First, it should be noted that in the following description, the refrigerant may be referred to as having a low temperature, a medium temperature, and/or a high temperature and/or a low pressure, a medium pressure, and/or a high pressure. Indeed, the description of low, medium and high temperature/low pressure, medium pressure and high pressure of the refrigerant refers to the relative pressure/temperature values of the same refrigerant within the vapor compression system 14 and/or the purge system 80. In other words, the vapor compression system may use a single refrigerant type that may have different pressure values throughout the vapor compression system 14 and/or the purge system 80.

In some embodiments, the vapor compression system 14 may utilize a controller 81 to control certain operational aspects of the purge system 80. The controller 81 may be any device employing a processor 83 (which may represent one or more processors), such as an application specific processor. The controller 81 may also include a memory device 85 for storing instructions executable by the processor 83 for performing the method and control actions described herein for the washing system 80. Processor 83 may include one or more processing devices, and memory 85 may include one or more tangible, non-transitory machine-readable media. By way of example, such machine-readable media can comprise RAM, ROM, EPROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, etc., or any other medium which can be used to carry or store desired program code in the form of machine-executable instructions or data structures and which can be accessed by the processor 83 or by any general purpose or special purpose computer or other machine with a processor.

To this end, the controller 81 may be communicatively coupled to one or more components of the washing system 80 via a communication system 87. In some embodiments, the communication system 87 may communicate over a wireless network (e.g., wireless local area network [ WLAN ], wireless wide area network [ WWAN ], near field communication [ NFC ]). In some embodiments, the communication system 87 may communicate over a wired network (e.g., local area network [ LAN ], wide area network [ WAN ]). For example, as shown in fig. 5 and 6, the controller 81 may be in communication with many elements of the washing system 80, such as pumps, valves, expansion devices, and other components. In some embodiments, the functions of controller 81 and control panel 40 (fig. 3 and 4) as described herein may be controlled by a single controller. In some embodiments, the single controller may be the control panel 40 or the controller 81.

As shown in fig. 5, the liquid pump 84 may draw refrigerant (e.g., a first refrigerant flow) from the evaporator 38 through a conduit 98. The refrigerant drawn from the evaporator 38 may have an intermediate pressure (e.g., about 5psia) and an intermediate temperature (e.g., about 40 degrees fahrenheit). In some embodiments, the refrigerant may be a two-phase mixture comprising a majority of refrigerant liquid and a portion of refrigerant vapor. Thus, in some embodiments, the refrigerant may first flow to the flash tank 82 to separate the two-phase mixture before flowing to the liquid pump 84. Indeed, in some embodiments, the purge system 80 may not utilize the flash tank 82. Within the flash tank 82, the two-phase mixture may separate, wherein due to the density difference, refrigerant liquid accumulates at the bottom of the flash tank 82 and refrigerant vapor accumulates at the top of the flash tank 82. The liquid pump 84 may then draw refrigerant liquid from the bottom of the flash tank 82 through conduit 100. As the refrigerant travels from the flash tank 82 to the pump 84, the refrigerant may have a moderate temperature (e.g., about 40 degrees fahrenheit) and a moderate pressure (e.g., about 5 psia). Accumulated refrigerant vapor in the flash tank 82 may be drawn to the evaporator 38 through a conduit 102. Specifically, the refrigerant vapor from the flash tank 82 may flow to a low pressure or outlet side of the evaporator 38. For example, a pressure differential between the low pressure side of the evaporator 38 and the flash tank 82 may draw refrigerant vapor from the flash tank 82 into the suction side of the evaporator 38. Indeed, the conduit 102 may be designed (e.g., sized, shaped, textured, etc.) such that refrigerant flowing through the conduit 102 is maintained at a sufficiently high pressure to flow into the evaporator 38. The refrigerant vapor may have an intermediate temperature (e.g., about 40 degrees fahrenheit) and an intermediate pressure (e.g., about 5psia) as it flows from the flash tank 82 to the evaporator 38.

The pump 84 may force refrigerant liquid through a conduit 104 to the controllable expansion device 86. The refrigerant liquid may have a medium temperature (e.g., about 45 degrees fahrenheit) and a high pressure (e.g., about 16psia) as it travels from the liquid pump 84 to the controllable expansion device 86. In practice, the refrigerant liquid exiting the liquid pump 84 may have a higher pressure and temperature relative to the refrigerant entering the liquid pump 84. In addition, the controller 81 may send one or more liquid pump signals to the liquid pump 84 to control the mass flow rate of refrigerant through the liquid pump 84.

As the refrigerant travels through the controllable expansion device 86, the controllable expansion device 86 may reduce the pressure, and therefore also the temperature, of the refrigerant. In some embodiments, the controllable expansion device 86 may be disposed vertically above the purge heat exchanger 88. After exiting the controllable expansion device 86, the refrigerant may travel through a conduit 106 to a purge coil 108 of the purge heat exchanger 88 due at least in part to the height difference between the controllable expansion device 86 and the purge heat exchanger 88. The refrigerant may have a low temperature (e.g., about 6 degrees fahrenheit) and a low pressure (e.g., about 3.5psia) as it travels from the controllable expansion device 86 to the purge heat exchanger 88. Further, in some embodiments, some portion of the refrigerant may evaporate as refrigerant vapor as the controllable expansion device 86 reduces the pressure of the refrigerant.

As discussed in further detail below, the refrigerant may exchange heat with a mixture of refrigerant vapor (e.g., the second refrigerant stream) and the NCG drawn from the condenser 34 or from another portion of the system as the refrigerant travels through the purge coil 108 of the purge heat exchanger 88. As described above, due to the vapor compression system 14 being at a low pressure relative to ambient pressure when operating, the NCG may be drawn into the evaporator 38 and travel through the vapor compression system 14 to accumulate in the condenser 34. Specifically, NCG may accumulate in a portion of the condenser 34. Thus, a mixture of NCG and refrigerant vapor can be drawn from that portion of the condenser 34. Generally, during normal operation, the portion of NCG accumulation may be substantially below the discharge baffle, near the middle of the condenser 34, near the outlet of the condenser 34, near the top of the condenser 34, or any combination thereof.

In some embodiments, the NCG that has accumulated in the condenser 34 may be mixed with the refrigerant vapor. The mixture of NCG and refrigerant vapor may be drawn through conduit 114 into purge heat exchanger 88 (such as a chamber of purge heat exchanger 88). Due to the pressure differential between the condenser 34 and the purge heat exchanger 88, a mixture of NCG and refrigerant vapor may be drawn into the purge heat exchanger 88. Further, in certain embodiments, the mixture of NCG and vapor may be drawn into the purge heat exchanger 88 due to a partial vacuum created in the purge heat exchanger 88 by condensation within the purge heat exchanger 88.

As the NCG and refrigerant vapor mixture contacts the low temperature surfaces of the purge coil 108, the refrigerant vapor will condense into a refrigerant liquid and create a partial vacuum within the purge heat exchanger 88, thereby drawing more of the NCG and refrigerant vapor mixture from the condenser 34 through conduit 114. Further, as the mixture of NCG and refrigerant vapor enters the purge heat exchanger 88 and the refrigerant vapor condenses into refrigerant liquid, the refrigerant liquid will collect at the bottom of the purge heat exchanger 88. Indeed, due at least in part to the density difference between the condensed refrigerant liquid and the NCG, the NCG will collect toward the top of the purge heat exchanger 88, while the condensed refrigerant liquid will collect at the bottom of the purge heat exchanger 88. Thus, as more refrigerant vapor in the mixture of NCG and refrigerant vapor condenses within the purge heat exchanger 88, the level of refrigerant liquid within the purge heat exchanger 88 will rise.

As described in further detail below, once the level of refrigerant liquid has reached a predetermined threshold in the purge heat exchanger 88, the refrigerant liquid will be discharged through conduit 115 to the condenser 34, the evaporator 38, or both, and the NCG will be pumped by pump 90 out of the purge heat exchanger 88 through conduit 116. In some embodiments, the purge heat exchanger 88 may be disposed vertically above the condenser 34 and the evaporator 38. In this manner, refrigerant liquid may flow to the condenser 34, the evaporator 38, or both, due at least in part to the difference in elevation of the purge heat exchanger 88 relative to the condenser 34 and the evaporator 38. In some embodiments, the condenser 34 may be disposed vertically above the evaporator 38, thereby allowing the refrigerant liquid to flow more easily from the purge heat exchanger 88 to the evaporator 38 than to the condenser 34. In addition, pump 90 may vent the NCG to atmosphere, as shown by arrow 117.

In some embodiments, the cleaning heat exchanger 88 may include one or more sensors 119, which may include one or more temperature sensors, pressure sensors, weight sensors, liquid level sensors, ultrasonic sensors, or any combination thereof. For example, one sensor 119 of the one or more sensors 119 may measure a level of refrigerant liquid within the purge heat exchanger 88 and send data regarding the level to the controller 81. If the liquid level approaches, matches, and/or exceeds a predetermined liquid level threshold, the controller 81 may send a signal to one or more of the shutoff valves 96 to allow refrigerant liquid to drain to the condenser 34, the evaporator 38, or both, as described above. Similarly, the controller 81 may send a signal to one or more of the pump 90 and/or the shut-off valve 96 to release the NCG to the atmosphere through the pump 90.

In some embodiments, the controller 81 may determine whether a large or predetermined amount of NCG is present within the condenser 34 before allowing the mixture of NCG and refrigerant vapor to enter the purge heat exchanger 88, such as by activating one or more of the shutoff valves 96. To determine whether a large or predetermined amount of NCG is present within the condenser 34, another sensor 119 of the one or more sensors 119 may measure one or more parameters related to the performance of the vapor compression system 14 and send data indicative of the one or more parameters to the controller 81 for analysis and processing. Specifically, the controller 81 may determine the performance of the vapor compression system 14 based on one or more parameters. If the controller 81 determines that the performance of the vapor compression system 14 is below a predetermined threshold, the controller 81 may allow the condenser 34 to be purged by opening the appropriate shutoff valve and allowing the mixture of NCG and refrigerant vapor to flow from the condenser 34 to the purge heat exchanger 88, as described above. In some embodiments, the controller 81 may purge the condenser 34 based on a predetermined schedule, as described above.

Additionally or in the alternative, one of the sensors 119 may measure the saturation temperature and the actual temperature within the condenser 34 and send data indicative of the saturation temperature and the actual temperature to the controller 81 for analysis and processing. The controller 81 may then determine whether the saturation temperature substantially matches the actual temperature. If the saturation temperature does not substantially match the actual temperature, the controller 81 may allow the condenser 34 to be purged by opening the appropriate shutoff valve 96 and allowing the mixture of NCG and refrigerant vapor to flow from the condenser 34 to the purge heat exchanger 88, as described above.

Further, as described above, the refrigerant traveling through the purge coil 108 of the purge heat exchanger 88 may exchange heat with the mixture of refrigerant vapor and NCG drawn from the condenser 34. More specifically, the refrigerant traveling through the purge coil 108 may absorb thermal energy from the mixture of refrigerant vapor and NCG and undergo a phase change from liquid to vapor and exit the purge coil 108 through conduit 118 to the ejector 94. In practice, the refrigerant vapor exiting the purge coil 108 may be superheated vapor having a moderate temperature (e.g., about 30 degrees fahrenheit) and a low pressure (e.g., about 3.5 degrees psia).

The refrigerant entering the purge coil 108 may be at a sufficiently low temperature in order to condense the refrigerant vapor drawn from the condenser 34. To this end, another sensor 119 of the one or more sensors 119 may measure the temperature of the refrigerant entering the wash coil 108 and send data indicative of the temperature of the refrigerant to the controller 81 for analysis and processing. In this manner, the controller 81 may control (e.g., further open and/or close) the controllable expansion device 86 to adjust the temperature of the refrigerant flowing into the purge coil 108 to achieve a sufficiently low temperature.

After exiting the wash coil 108, the refrigerant vapor may be pulled into the ejector 94 due to a pressure differential relative to the flow of refrigerant vapor that may enter the ejector 94 from the condenser 34 through the conduit 120. The ejector 94 may also help to pull the refrigerant through the expansion device 86 and the purge coil 108. More specifically, high pressure refrigerant vapor from the condenser 34 may enter the ejector 94 through the nozzle 122 and increase in flow rate and decrease in pressure as it flows through the nozzle 122. In this manner, the now low pressure refrigerant vapor exiting the nozzle 122 may draw refrigerant vapor from the purge coil 108, thereby mixing the high pressure refrigerant vapor from the condenser 32 with the refrigerant vapor from the purge coil 108 within the ejector 94. As the refrigerant vapors mix within the ejector 94, they will travel through the ejector 94 and exit through the diffusion cone 124 of the ejector 94. In addition, the refrigerant vapor will mix as it travels through the ejector 94, which may result in a reduction in velocity and a reduction in pressure. As the refrigerant vapor moves through the diffusion cone 124, the diffusion cone 124 will further reduce the flow rate of the refrigerant vapor exiting the ejector 94 and increase the pressure. The refrigerant vapor exiting the ejector 94 may then be delivered to the low pressure side of the evaporator 38 via conduit 126. More specifically, the refrigerant vapor exiting the ejector 94 is drawn into the evaporator 38 due to a pressure differential relative to the low pressure refrigerant within the evaporator 38. In particular, the refrigerant flowing from the ejector 94 to the evaporator 38 may be at a moderate temperature (e.g., about 40 degrees Fahrenheit) and a moderate pressure (e.g., about 5 psia).

As described above, the embodiment described with respect to fig. 5 may be utilized when the vapor compression system 14 is in operation. Indeed, when in operation, the low pressure within the vapor compression system 14 may draw in ambient air and/or other non-condensable gases. However, when the vapor compression system 14 is not operating, the vapor compression system 14 may still contain a certain amount of residual NCG, particularly in the upper portion of the condenser 34. However, when the vapor compression system 14 is not operating, the ejector 94 may not draw high pressure refrigerant from the condenser 34 to pull refrigerant from the purge coil 108 because the pressure level of the refrigerant within the vapor compression system 14 may level when the vapor compression system 14 is not operating. Thus, as shown in fig. 6, the cleaning system 80 may utilize the thermoelectric assembly 150 and/or the adsorption chamber 152 to clean the vapor compression system 14 from residual NCG.

For example, as shown in fig. 6, when the vapor compression system 14 is not operating, the liquid pump 84 may draw refrigerant from the evaporator 38 through a conduit 100. The liquid pump 84 may then pump the refrigerant through the conduit 104 via the controllable expansion valve 86 to the purge coil 108 of the purge heat exchanger 88. As it travels from the liquid pump 84 to the cleaning coil 108, the temperature of the refrigerant may decrease as the thermoelectric assembly 150 absorbs heat from the refrigerant and releases heat to the surrounding atmosphere. Specifically, the thermoelectric assembly 150 may utilize a power source 154 to induce an electrical gradient within the thermoelectric assembly 150. The power supply 154 may be any suitable power supply, including but not limited to: an electrical grid, a battery, a solar panel, a generator, a gas engine, the vapor compression system 14, or any combination thereof. The thermoelectric assembly 150 may convert the electrical gradient into a thermal gradient through a thermoelectric effect or a Peltier-Seebeck (Peltier-Seebeck) effect. In particular, the thermoelectric assembly 150 may utilize a thermal gradient to absorb heat from the refrigerant flowing from the liquid pump 84 to the cleaning coil 108.

In the current embodiment, the thermoelectric assembly 150 is disposed on the conduit 104 between the liquid pump 84 and the controllable expansion valve 86 and is configured to absorb heat from the refrigerant as the refrigerant flows through the conduit 104. However, in some embodiments, the thermoelectric assembly 150 may be disposed on the conduit 106 between the controllable expansion valve 106 and the wash coil 108 and may be configured to absorb heat from the refrigerant as the refrigerant flows through the conduit 106. In some embodiments, conduits 104 and/or 106 may be thermally insulated. Specifically, the thermoelectric assembly 150a or the thermoelectric module in the thermoelectric assembly 150 may include a thermal paste 156, a thermoelectric device 158, a heat sink 160, and a fan 162. For example, the thermoelectric assembly 150a is coupled to a conduit (such as conduit 104 and/or conduit 106) by thermal glue 156, which may be coupled to a first side of the thermoelectric device 158. The second side of the thermoelectric device 158 is coupled to a heat sink 160, which in turn is coupled to a fan 162. The thermoelectric assembly 150 may include any suitable number of individual thermoelectric assemblies 150a or thermoelectric modules. For example, in some embodiments, the cleaning system 80 may include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or any other suitable number of thermoelectric assemblies 150 a. In some embodiments, a conduit coupled with the thermoelectric assembly 150 (such as conduit 104 and/or conduit 106) may include internal fins 161 to facilitate heat transfer to the thermoelectric assembly 150.

As the thermoelectric assembly 150 absorbs heat from the refrigerant, the refrigerant may become subcooled. Accordingly, the controllable expansion valve 86 may be fully or substantially open (e.g., as indicated by the controller 81) such that no or a minimal amount of refrigerant evaporates (e.g., the refrigerant remains subcooled) before reaching the purge coil 108. As the subcooled refrigerant travels through purge coil 108, the subcooled refrigerant may exchange heat with a mixture of NCG and refrigerant vapor that may have been pulled into purge heat exchanger 88 from condenser 34, as described above with reference to fig. 5. However, unlike the embodiment described above in fig. 5, it should be noted that in some embodiments, the subcooled refrigerant traveling through purge coil 108 may be sufficiently subcooled such that the subcooled refrigerant remains substantially (if not entirely) in a liquid state while traveling through purge coil 108 and absorbs heat from the mixture of NCG and refrigerant vapor. In some embodiments, the fluid pump 84 may force the subcooled refrigerant through the purge coil 108 at a high flow rate (e.g., as indicated by the controller 81) such that the subcooled refrigerant remains in a liquid state and absorbs heat from the NCG and refrigerant vapor mixture substantially, if not entirely, while traveling through the purge coil 108. In some embodiments, to ensure that the refrigerant remains in a liquid state as it travels through the wash coil 108, the controller 81 may send a signal to one or more of the shut-off valves 96 and the liquid pump 84 such that the thermoelectric assembly 150 is in heat exchange relationship with the refrigerant for an extended period of time, thereby further reducing the temperature of the refrigerant before it flows into the wash coil 108.

Due at least in part to the liquid state of the refrigerant within the purge coil 108, head pressure and/or gravity may enable the refrigerant to flow back through the conduit 163 to the evaporator 38. Further, as described above, the refrigerant vapor in the mixture of NCG and refrigerant vapor pulled from the condenser 34 may condense and accumulate at the bottom of the purge heat exchanger 88 and eventually return to the condenser 34 and/or the evaporator 38 once the refrigerant level reaches a predetermined threshold within the purge heat exchanger 88.

As also shown in fig. 6, in some embodiments, the purge system 80 may utilize an adsorbent chamber 152 to purge the vapor compression system 14 of ambient air or other non-condensable gases. For example, in some embodiments, the NCG gas/refrigerant vapor pulled by the pump 90 from the purge heat exchanger 88 may contain some portion of the refrigerant vapor as well as the NCG. Therefore, the adsorption chamber 152 can remove the refrigerant vapor portion sucked by the pump 90 before discharging the NCG into the atmosphere. To illustrate, the pump 90 may pump a mixture (or "mixture") of NCG and refrigerant vapor through the conduit 164 to one or more of the adsorption chambers 152. As the mixture traverses one of the adsorbent chambers 152, the mixture may pass through the modifying material 166 of the adsorbent chamber 152 and, due to the properties of the modifying material 166 and the refrigerant vapor, the refrigerant vapor may be adsorbed or drawn into and/or onto the modifying material 166. For example, the electrochemical properties facilitate adsorption, as described herein. Furthermore, as the mixture traverses the adsorption chamber 152, the NCG may not be adsorbed into the modifying material 166, also due at least in part to the properties of the NCG and modifying material 166. Thus, the NCG may pass through the modified material 162 and continue through the air outlet valve 168, as shown by arrow 170, for discharge into the atmosphere.

As the modifying material 166 adsorbs the refrigerant, the modifying material 166 eventually becomes saturated with the refrigerant and may no longer be effective at adsorbing additional refrigerant. Accordingly, a heater 169, such as an immersion heater, an external cable heater, or a ribbon heater, may be activated to provide thermal energy to the modification material 166. The modifying material 166 transfers thermal energy to the refrigerant. Over time, the thermal energy applied to the refrigerant will cause the bonding of the modifying material 166 and the refrigerant to be overcome, causing the modifying material 166 to release the refrigerant in a vapor state. Once released from the modifying material 166, the refrigerant vapor may have a high pressure relative to the pressure within the evaporator 38 such that the refrigerant vapor flows to the evaporator 38 through the conduit 170. In some embodiments, the adsorption chamber 152 may utilize a vacuum pump to create a pulling force at the outlet of the adsorption chamber 152. The pulling force may be stronger than the electrochemical bonding of the modifying material 166 and the refrigerant, such that the refrigerant is pulled from the modifying material 166.

In some embodiments, the inlet valve 166 may allow the mixture to flow to only certain adsorbent chambers 152 at a time. In this manner, the adsorbent chamber 152 may continue to receive and filter the mixture, as described above. For example, the controller 81 may control the shut-off valve 96 to allow one or more particular ones of the adsorbent chambers 152 to filter the mixture. Once a particular adsorbent chamber 152 becomes saturated with refrigerant, the controller 81 may stop the flow of the mixture to the particular adsorbent chamber 152 and allow the mixture to flow to a different adsorbent chamber 152. Once the controller 81 has stopped the flow to a particular adsorption chamber 152, the controller may activate the heater 169 associated with the particular adsorption chamber 152 to allow the refrigerant vapor to flow to the evaporator 38, as described above. In fact, different adsorbent chambers 152 may continue to filter the mixture as a particular adsorbent chamber 152 is heated. Once a particular adsorption chamber 152 is not sufficiently saturated with refrigerant, the controller 81 may once again activate one or more of the shut-off valves 96 to allow the mixture to flow to the particular adsorption chamber 152. To this end, the cleaning system 80 may include 1, 2, 3, 4, 5, 6, or any other suitable number of individual adsorbent chambers 152 to allow for continuous filtration of the mixture. Further, it should be noted that the embodiments discussed herein with respect to fig. 6, specifically the thermoelectric assembly 150 and/or the adsorption chamber 152, may be utilized if the vapor compression system 14 is operating or if the vapor compression system 14 is not operating.

In certain embodiments, as shown in fig. 7, the purge system 80 may utilize a pump 202, such as a reciprocating/membrane oil-free vapor pump, disposed upstream of the purge heat exchanger 88, configured to increase the pressure of the mixture prior to the mixture entering the purge heat exchanger 88. In this manner, the temperature at which the refrigerant vapor in the mixture condenses within the purge heat exchanger 88 is increased, thereby reducing the load on the purge system 80. In addition, the purge system 80 may include a solenoid valve 204, an injector 206 (such as injector 94), a purge heat exchanger 88 (which may be a shell and tube heat exchanger), and one or more shut-off valves 96.

Generally, the purge system 80 may utilize refrigerant from the vapor compression system 14 to purge the vapor compression system 14 of NCG. In other words, the refrigerant from the vapor compression system 14 may be used as a cooling source for condensing the mixture of refrigerant and NCG within the purge system 80. For example, the purge system 80 may draw a mixture of NCG and vapor refrigerant from the condenser 34. The mixture is then pumped to a purge heat exchanger 88 where the vapor refrigerant condenses, thereby separating the refrigerant in the mixture from the NCG in the mixture. In particular, to condense the vapor refrigerant, the mixture is placed in heat exchange relationship with refrigerant drawn from downstream of the expansion device 36 of the vapor compression system 14. The condensed refrigerant is then discharged to the condenser 34, and the NCG is released to the atmosphere.

To further illustrate, the pump 202 may draw the mixture of vapor refrigerant and NCG from the condenser 34 through conduit 203. In certain embodiments, the mixture drawn from the condenser 34 may be approximately 94 ° F and 26 psi. The pump 202 may increase the pressure of the mixture as it is pumped from the condenser 34 and delivered through the conduit 205 to the purge heat exchanger 88. In certain embodiments, the pump 202 may increase the pressure of the mixture by about 50 psi. For example, after passing through the pump 202, the mixture may be about 160 ° F and 76psi, and may be superheated steam at a flow rate of about 10lbm/hr (pounds mass per hour). Due to the increased pressure, the refrigerant vapor within the mixture will condense at the higher heat exchange temperature within the purge heat exchanger 88, as described above. That is, as the pump 202 increases the pressure of the mixture, the condensation temperature of the vapor refrigerant correspondingly increases, and thus the vapor refrigerant will condense with less cooling. In certain embodiments, the pump 202 may increase the pressure of the mixture such that the vapor refrigerant may condense at approximately 43 ° F within the purge heat exchanger 88. In certain embodiments, the pump 202 may include two pumps 199 arranged in series with each other. In this way, the load is split or split between the two pumps 199, which may result in less stress on the individual pumps 199, thereby resulting in less maintenance on the pumps 199.

As the purge heat exchanger 88 condenses the vapor refrigerant to liquid refrigerant, the liquid refrigerant may collect in the base of the purge heat exchanger 88. As discussed above, once the liquid refrigerant reaches the threshold volume within the purge heat exchanger 88, the controller 81 may operate the shutoff valve 96 to discharge the liquid refrigerant from the purge heat exchanger 88 to the condenser 34 via conduit 207. In certain embodiments, the liquid refrigerant may be continuously discharged to the condenser 34. In certain embodiments, the liquid refrigerant discharged from the purge heat exchanger 88 may be a subcooled liquid at about 160 ° F and 76 psi.

Further, when the refrigerant and NCG are separated within the purge heat exchanger 88, the NCG may be released to the atmosphere through the solenoid valve 204 via conduit 209. For example, the pump 202 may increase the pressure of the mixture entering the purge heat exchanger 88 such that the pressure of the NCG separated from the refrigerant in the mixture is greater than atmospheric pressure. Thus, the pressure differential between the NCG in the purge heat exchanger 88 and the atmosphere may drive the NCG through the solenoid valve 204 and to the atmosphere. In some embodiments, once the liquid level within the purge heat exchanger 88 reaches a threshold, the controller 81 may activate the solenoid valve 204 to release the NCG to the atmosphere. In certain embodiments, the controller 81 may prevent the mixture from entering the purge heat exchanger 88, such as by actuating one or more of the shut-off valves 96 and/or deactivating the pump 202, prior to releasing the NCG through the solenoid valve 204. In this manner, purge system 80 may ensure that substantially all of the vapor refrigerant in the mixture within purge heat exchanger 88 has condensed, thereby preventing the release of vapor refrigerant through solenoid valve 204.

As discussed above, the vapor refrigerant and the NCG in the mixture may separate within the purge heat exchanger 88 as the vapor refrigerant condenses to liquid refrigerant. In particular, to condense the vapor refrigerant, the mixture may be placed in heat exchange relationship with liquid refrigerant drawn from the vapor compression system 14. More specifically, liquid refrigerant may be drawn from the vapor compression system 14 refrigerant loop downstream of the expansion device 36 via conduit 211. As discussed herein, the refrigerant drawn from the refrigerant loop of the vapor compression system 14 at a location downstream of the expansion device 36 and used to condense the vapor refrigerant in the mixture may be referred to as "expanded refrigerant". The expanded refrigerant may be substantially liquid and/or may contain some flash gas.

To condense the vapor refrigerant in the mixture within the purge heat exchanger 88, the expanded refrigerant may be routed through tubes 210 of the purge heat exchanger 88. As the expanded refrigerant travels through the tubes 210 of the purge heat exchanger 88, the expanded refrigerant may exchange heat with the mixture. In particular, the expanding refrigerant may absorb heat from the mixture. Thus, as the expanded refrigerant exits the tubes 210 of the purge heat exchanger 88, the expanded refrigerant may be a superheated vapor. For example, the expanded refrigerant may exit the purge heat exchanger 88 at about 43 ° F and 9psi with a flow rate of about 8.5 lbm/hr.

To draw the expanded refrigerant through the tubes 210 of the purge heat exchanger 88, the purge system 80 may utilize an ejector 206. The injector 206 may function similar to the injector 94, as described above. For example, the ejector 206 may utilize a pressure differential to draw expanded refrigerant through a tube 210 of the purge heat exchanger 88 and through a conduit 212. Specifically, the ejector 206 may utilize refrigerant drawn through a conduit 213 fluidly coupled to a location along a refrigerant loop of the vapor compression system 14 directly downstream of the compressor 32, such as between the compressor 32 and the condenser 34. The ejector 206 may function with increased performance due at least in part to the low pressure differential between the expanded refrigerant flowing through the tube 210 and the refrigerant drawn from the refrigerant loop downstream of the compressor 32. For example, the pressure of the expanded refrigerant drawn from tube 210 may be between about 8psi and 9psi, and the pressure of the refrigerant drawn downstream from compressor 32 may be about 26 psi. The ejector 206 may then pass the combined refrigerant to the evaporator 38 via conduit 215. Further, liquid refrigerant may flow from the purge heat exchanger 88 to the evaporator 38 due at least in part to a height difference between the purge heat exchanger 88 and the evaporator 38. Additionally or in the alternative, liquid refrigerant may flow from the purge heat exchanger 88 to the condenser 34 due at least in part to a height difference between the purge heat exchanger 88 and the condenser 34.

Further, in certain embodiments, such as the embodiment illustrated in fig. 8, the purge system 80 may utilize a liquid pump 222 (such as liquid pump 84) to draw refrigerant from the evaporator 38 to condense vapor refrigerant in the mixture within the purge heat exchanger 88. Additionally, the purge system 80 may utilize a pump 202 (such as a reciprocating/membrane oil-free vapor pump), a solenoid valve 204, a purge heat exchanger 88 (which may be a direct contact heat exchanger), the pump 202, a liquid pump 222, and one or more shutoff valves 96 to purge the vapor compression system 14 of NCG.

Generally, the purge system 80 may utilize refrigerant drawn from the vapor compression system 14 to purge the vapor compression system 14 of NCG. For example, the purge system 80 may draw NCG from the condenser 34, which may be mixed with vapor refrigerant. The mixture of NCG and vapor refrigerant is then pumped to a purge heat exchanger 88 where the vapor refrigerant condenses, thereby separating the refrigerant in the mixture from the NCG in the mixture. In particular, to condense the vapor refrigerant, the mixture is placed in heat exchange relationship with the refrigerant, which may be drawn from the evaporator 38 or from a location along the refrigerant loop of the vapor compression system 14 upstream of the expansion device 36. The condensed refrigerant in the purge heat exchanger 88 is then discharged to the evaporator 38 and/or the condenser 34, and the NCG is released to the atmosphere.

To further illustrate, the pump 202 may draw a mixture of refrigerant vapor and NCG from the condenser 34 through conduit 203. In certain embodiments, the mixture drawn from the condenser 34 may be approximately 94 ° F and 26 psi. The pump 202 may increase the pressure of the mixture as it is pumped from the condenser 34 and delivered through the conduit 205 to the purge heat exchanger 88. In certain embodiments, the pump 202 may increase the pressure of the mixture by about 50 psi. In particular, after passing through the pump 202, the mixture may be superheated steam. For example, the mixture may be about 160 ° F and 76psi with a flow rate of about 10lbm/hr (pounds mass per hour). In this manner, the refrigerant vapor will condense at the higher heat exchange temperature within the purge heat exchanger 88. That is, as the pump 202 increases the pressure of the mixture, the condensation temperature of the refrigerant correspondingly increases, and thus condenses with less cooling.

Once pumped into the purge heat exchanger 88, the mixture may exchange heat with refrigerant drawn from the evaporator 38 and/or upstream of the expansion device 36. More specifically, the liquid pump 222 may draw liquid refrigerant from a bottom or flooded section of the evaporator 38 through a conduit 223, increase the pressure of the liquid refrigerant, and deliver the liquid refrigerant to the purge heat exchanger 88 through a conduit 225 to exchange heat with the mixture. The liquid refrigerant drawn from the evaporator 38 may be approximately 43 ° F and 9psi, and may be a subcooled liquid. The liquid pump 222 may increase the pressure of the liquid refrigerant, such as to about 76psi, and may deliver the liquid refrigerant in a subcooled state to the purge heat exchanger 88 at about 30 lbm/hr. Further, it should be noted that the output pressure of the mixture through pump 202 may substantially match the output pressure of the liquid refrigerant exiting liquid pump 222. In practice, the pump 202 may deliver the mixture to the purge heat exchanger 88 at about 160F and 76psi, with a flow rate of about 10 lbm/hr.

In some embodiments, liquid pump 222 may draw liquid refrigerant from upstream of expansion valve 36, as discussed above. In such embodiments, the liquid pump 222 may function with increased efficiency due to the reduced pressure differential. For example, the liquid refrigerant upstream of the expansion device 36 may be at a higher pressure than the liquid refrigerant of the evaporator 38. Thus, to match the pressure output of the pump 202, the liquid pump 222 may have to work less if the liquid pump 222 is pumping liquid refrigerant drawn upstream from the expansion device 36.

The liquid refrigerant drawn from the evaporator 38 and/or upstream from the expansion device 36 may be supplied to the purge heat exchanger 88 by a spray system 224, which may include a spray system and a sprayer housing configured to disperse the liquid refrigerant throughout the interior volume of the purge heat exchanger 88. As the liquid refrigerant mixes with the mixture of vapor refrigerant and NCG, the vapor refrigerant in the mixture may condense into liquid refrigerant, which may then form a pool of liquid refrigerant at the bottom of the purge heat exchanger 88. The liquid refrigerant may then be discharged to the evaporator 38, as shown, via conduit 226. For example, as discussed above, once the liquid refrigerant reaches a threshold volume within the purge heat exchanger 88, the controller 81 may operate the shut-off valve 96 to drain the liquid refrigerant to the evaporator 38. In certain embodiments, the liquid refrigerant may be continuously discharged to the evaporator 38 and/or to the condenser 34. In certain embodiments, the liquid refrigerant discharged from the purge heat exchanger 88 may be a subcooled liquid at about 132 ° F and 76 psi.

Further, when the refrigerant and NCG in the mixture are separated within the purge heat exchanger 88, the NCG may be released to the atmosphere through the solenoid valve 204. For example, the pump 202 may increase the pressure of the mixture of vapor refrigerant and NCG such that the pressure of the NCG within the purge heat exchanger 88 is greater than atmospheric pressure. Thus, the pressure differential between the NCG in purge heat exchanger 88 and the atmosphere may drive the NCG to flow through solenoid valve 204 to the atmosphere. In some embodiments, once the level of the purge heat exchanger 88 reaches a threshold, the controller 81 may activate the solenoid valve 204 to release the NCG to the atmosphere. In certain embodiments, the controller 81 may prevent the mixture from entering the purge heat exchanger 88, such as by actuating one or more shut-off valves and/or deactivating the pump 202, prior to releasing the NCG through the solenoid valve 204. In this manner, purge system 80 may ensure that substantially all of the vapor refrigerant in the mixture within purge heat exchanger 88 has condensed, thereby preventing the release of vapor refrigerant through solenoid valve 204. Further, liquid refrigerant may flow from the purge heat exchanger 88 to the evaporator 38 due at least in part to a height difference between the purge heat exchanger 88 and the evaporator 38. Additionally or in the alternative, liquid refrigerant may flow from the purge heat exchanger 88 to the condenser 34 due at least in part to a height difference between the purge heat exchanger 88 and the condenser 34.

As discussed above, in certain embodiments, the pump 202 may include two pumps 199 arranged in series. In this way, the load is split between the two pumps 199, which may result in less stress being induced on each individual pump 199, thereby resulting in less maintenance on the pumps 199. Similarly, in certain embodiments, the liquid pump 222 may include two liquid pumps 227 arranged in series. In this way, the load is split between the two liquid pumps 227, which may result in less stress being induced on each individual liquid pump 227, thereby resulting in less maintenance on the liquid pumps 227.

Additionally, the embodiment discussed above with reference to fig. 8 may be utilized when the vapor compression system 14 is shut down. Indeed, although discussed with reference to the embodiment of fig. 8, the purge system 80 does not necessarily take advantage of the conditions created by the vapor compression system 14 during operation. That is, the pump 202 and the liquid pump 222 may induce a pressure utilized by the function of the purge system 80 to purge the vapor compression system 14 of NCG.

Further, in certain embodiments, as shown in fig. 9, the purge system 80 may draw refrigerant from the refrigerant loop of the vapor compression system 14 upstream of the expansion device 36 to condense vapor refrigerant in the mixture. In particular, the purge system 80 may utilize a second expansion device 230 to expand the refrigerant to an intermediate pressure between the pressures of the condenser 34 and the evaporator 38, such that the pressure differential drives the refrigerant through the tubes 210 of the purge heat exchanger 88. In addition, the purge system 80 may utilize a pump 202, a purge heat exchanger 88 (such as a shell and tube heat exchanger), a solenoid valve 204, and a three-way valve 228 to remove NCG that may have accumulated in the condenser 34, as discussed above.

Generally, the purge system 80 may utilize refrigerant drawn from the vapor compression system 14 to purge the vapor compression system 14 of NCG. For example, the purge system 80 may draw NCG from the condenser 34, possibly in admixture with vapor refrigerant. The mixture is then pumped to a purge heat exchanger 88 where the vapor refrigerant condenses, thereby separating the refrigerant in the mixture from the NCG in the mixture. For example, to condense the vapor refrigerant, the mixture is placed in heat exchange relationship with refrigerant drawn upstream of the expansion device 36. The condensed refrigerant is then discharged to the condenser 34, and the NCG is released to the atmosphere.

To further illustrate, the pump 202 may draw a mixture of refrigerant vapor and NCG from the condenser 34 through conduit 203. In certain embodiments, the mixture drawn from the condenser 34 may be approximately 94 ° F and 26 psi. The pump 202 may increase the pressure of the mixture as it is pumped from the condenser 34 and delivered through the conduit 205 to the purge heat exchanger 88. In certain embodiments, the pump 202 may increase the pressure of the mixture by about 50 psi. For example, after passing through the pump 202, the mixture may be superheated steam at 160 ° F and 76psi with a flow rate of about 10lbm/hr (pounds mass per hour). In this manner, the refrigerant vapor within the mixture may more readily condense within the purge heat exchanger 88. That is, as the pump 202 increases the pressure of the mixture, the condensation temperature of the refrigerant correspondingly increases, and thus condenses with less cooling.

As the purge heat exchanger 88 condenses the vapor refrigerant to liquid refrigerant, the liquid refrigerant may collect in the base of the purge heat exchanger 88. As discussed above, once the liquid refrigerant reaches a threshold volume within the purge heat exchanger 88, the controller 81 may operate the shut-off valve 96 to drain the liquid refrigerant to the condenser 34 via conduit 207. In certain embodiments, the liquid refrigerant may be continuously discharged to the condenser 34. In certain embodiments, the liquid refrigerant discharged from the purge heat exchanger 88 may be a subcooled liquid at about 160 ° F and 76 psi.

Further, when the vapor refrigerant in the mixture and the NCG are separated within the purge heat exchanger 88, the NCG may be released to the atmosphere through the solenoid valve 204 via conduit 209. For example, the pump 202 may raise the pressure of the mixture of NCG and vapor refrigerant such that the pressure of the NCG within the purge heat exchanger 88 is greater than atmospheric pressure. Thus, the pressure differential between the NCG in purge heat exchanger 88 and the atmosphere may drive the NCG to flow through solenoid valve 204 to the atmosphere. In some embodiments, once the internal pressure of the purge heat exchanger 88 reaches a threshold, the controller 81 may activate the solenoid valve 204 to release the NCG to atmosphere. In certain embodiments, the controller 81 may block the mixture from entering the purge heat exchanger 88, such as by actuating one or more shut-off valves 96 and/or deactivating the pump 202, prior to releasing the NCG through the solenoid valve. In this manner, purge system 80 may ensure that substantially all of the vapor refrigerant in the mixture within purge heat exchanger 88 has condensed, thereby preventing the release of vapor refrigerant through solenoid valve 204.

To condense the vapor refrigerant in the mixture, the purge system 80 may place the mixture in heat exchange relationship with the liquid refrigerant in the purge heat exchanger 88. Liquid refrigerant may be drawn from the refrigerant loop of the vapor compression system 14 at a location upstream of the expansion device 36 and through the three-way valve 228. Liquid refrigerant drawn from the refrigerant loop may be expanded to an intermediate pressure via a second expansion device 230 before entering the purge heat exchanger 88. In particular, the intermediate pressure may be higher than the pressure of the evaporator 38 and lower than the pressure of the condenser 34. For example, the intermediate pressure may be between about 9psi and 26 psi. As another example, the intermediate pressure may be about 10psi to 12psi, and the pressure of the evaporator 38 may be about 9 psi. Thus, liquid refrigerant may flow through tubes 210 of purge heat exchanger 88, evaporate, and flow to evaporator 38 through conduit 238 due at least in part to the pressure differential between the vapor refrigerant and evaporator 38. For example, after exiting the purge heat exchanger 88, the vapor refrigerant may be about 52 ° F and 11psi, while the refrigerant in the evaporator 38 may be about 9 psi. Further, vapor refrigerant may flow from the purge heat exchanger 88 to the evaporator 38 due at least in part to the height difference between the purge heat exchanger 88 and the evaporator 38. Additionally or in the alternative, vapor refrigerant may flow from the purge heat exchanger 88 to the condenser 34 due at least in part to a height difference between the purge heat exchanger 88 and the condenser 34.

Further, as shown in fig. 5-9 c, in some embodiments, pumps, such as liquid pump 84, pump 90, pump 202, and/or liquid pump 222, may be powered by one or more motors 180, which may be any suitable motor. In some embodiments, the controller 81 may control the pump by communicating with one or more motors 180. In some embodiments, the one or more motors 180 may receive power from a power source 154, which may be similar to the power source 154 used to power the thermoelectric assembly 150.

Accordingly, the present disclosure relates to systems and methods for purging a low pressure HVAC & R system (e.g., chiller system, vapor compression system) of NCGs that may enter the HVAC & R system during operation. Specifically, the purging system may purge the HVAC & R system of NCGs by utilizing refrigerant drawn from the HVAC & R system. In other words, the first refrigerant stream of the HVAC & R system mixed with the NCG may be purged of the NCG by condensing the first refrigerant stream and separating the first refrigerant stream from the NCG using the second refrigerant stream of the HVAC & R system as a cooling source. The disclosed embodiments are cost effective relative to conventional purging methods and enable HVAC & R systems to purge NCGs without using an additional refrigerant loop with additional refrigerant.

Although only certain features and embodiments have been illustrated and described, many modifications and changes may occur to those skilled in the art (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters (e.g., temperatures, pressures, etc.), mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited in the claims. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention. Furthermore, in an effort to provide a concise description of the exemplary embodiments, all features of an actual implementation may not have been described (i.e., those unrelated to the presently contemplated best mode of carrying out the invention, or those unrelated to enabling the invention). It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made. Such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure, without undue experimentation.

Claims

1. A heating, ventilation, air conditioning and refrigeration (HVAC & R) system comprising:

a refrigerant loop;

a compressor disposed along the refrigerant loop, wherein the compressor is configured to circulate a refrigerant through the refrigerant loop;

an evaporator disposed along the refrigerant loop, wherein the evaporator is configured to place the refrigerant in heat exchange relationship with a first cooling fluid;

a condenser disposed along the refrigerant loop, wherein the condenser is configured to place the refrigerant in heat exchange relationship with a second cooling fluid; and

a purging system configured to purge the HVAC & R system of non-condensable gases, the purging system comprising:

a liquid pump configured to draw a first flow of refrigerant from the evaporator;

a controllable expansion valve configured to receive the first refrigerant stream from the liquid pump and reduce a temperature of the first refrigerant stream; and

a purge heat exchanger comprising a purge coil, wherein the purge coil is configured to receive the first refrigerant stream from the controllable expansion valve, wherein a chamber of the purge heat exchanger is configured to draw a mixture comprising the non-condensable gases and a second refrigerant stream from the condenser, and wherein the purge heat exchanger is configured to separate the non-condensable gases in the mixture from the second refrigerant stream in the mixture using the first refrigerant stream.

2. The HVAC & R system of claim 1, comprising an ejector configured to receive the first refrigerant flow from the purge coil, wherein the ejector is configured to increase a pressure of the first refrigerant flow with the second refrigerant flow from the condenser.

3. The HVAC & R system of claim 2, wherein the evaporator is configured to receive the second refrigerant flow and the first refrigerant flow discharged from the ejector.

4. The HVAC & R system of claim 1, wherein the purge system further comprises a pump configured to remove the non-condensable gases in the mixture from the purge heat exchanger.

5. The HVAC & R system of claim 1, wherein the purging system further comprises a conduit configured to flow the first refrigerant flow from the liquid pump to the controllable expansion valve, and wherein one or more thermoelectric assemblies are coupled to the conduit and configured to remove thermal energy from the first refrigerant flow flowing through the conduit.

6. The HVAC & R system of claim 5, wherein each of the one or more thermoelectric assemblies is configured to remove thermal energy of the first refrigerant flow by converting an electrical gradient into a thermal gradient.

7. The HVAC & R system of claim 1, wherein the purging system further comprises one or more adsorbent chambers configured to receive the mixture from the purging heat exchanger, and wherein each adsorbent chamber of the one or more adsorbent chambers is configured to separate the non-condensable gases in the mixture from the second refrigerant stream in the mixture.

8. The HVAC & R system of claim 7, wherein the one or more adsorbent chambers are configured to vent the non-condensable gases in the mixture to the atmosphere and to flow the second refrigerant stream in the mixture to the evaporator.

9. The HVAC & R system of claim 1, wherein the liquid pump is configured to draw the first flow of refrigerant from the evaporator through a flash tank, wherein the first flow of refrigerant drawn from the evaporator comprises a refrigerant liquid and a refrigerant vapor, and wherein the flash tank is configured to separate the refrigerant liquid from the refrigerant vapor.

10. The HVAC & R system of claim 9, wherein the flash tank is configured to flow the refrigerant liquid to the liquid pump and to flow refrigerant vapor to the evaporator.

11. The HVAC & R system of claim 1, wherein the purge heat exchanger is configured to flow the second refrigerant stream of the mixture into the condenser, the evaporator, or both.

12. A heating, ventilation, air conditioning and refrigeration (HVAC & R) system comprising:

a refrigerant loop;

a compressor disposed along the refrigerant loop and configured to circulate a refrigerant through the refrigerant loop;

an evaporator disposed along the refrigerant loop and configured to place the refrigerant in heat exchange relationship with a first cooling fluid;

a condenser disposed along the refrigerant loop and configured to place the refrigerant in heat exchange relationship with a second cooling fluid; and

a purging system configured to purge the HVAC & R system of non-condensable gases (NCGs), the purging system comprising:

a purge heat exchanger configured to separate a mixture drawn from the condenser with a first refrigerant stream of the refrigerant drawn from the evaporator, wherein the mixture comprises the NCG from the condenser and a second refrigerant stream of the refrigerant, and wherein separating the mixture comprises separating the NCG from the second refrigerant stream; and

one or more thermoelectric assemblies configured to remove thermal energy from the second refrigerant stream.

13. The HVAC & R system of claim 12, wherein the purge system further comprises a liquid pump configured to draw the first flow of refrigerant from the evaporator and push the first flow of refrigerant through the one or more thermoelectric components to the purge heat exchanger.

14. The HVAC & R system of claim 13, wherein the purging system further comprises a conduit configured to flow the first refrigerant flow from the liquid pump to the purging heat exchanger, and wherein the one or more thermoelectric assemblies are coupled to the conduit.

15. The HVAC & R system of claim 14, wherein each of the one or more thermoelectric assemblies comprises:

a thermal paste configured to couple the thermoelectric assembly to the conduit;

a thermoelectric assembly coupled to the thermal gel and configured to remove thermal energy from the first refrigerant flow by converting an electrical gradient to a thermal gradient;

a heat sink coupled to the thermoelectric assembly; and

a fan coupled to the heat sink.

16. The HVAC & R system of claim 12, wherein the purge heat exchanger comprises a purge coil configured to receive the first refrigerant stream.

17. The HVAC & R system of claim 12, wherein the purge system further comprises a pump configured to remove the NCG from the purge heat exchanger.

18. The HVAC & R system of claim 12, wherein the purge heat exchanger is configured to flow the second refrigerant stream to the condenser, the evaporator, or both.

19. The HVAC & R system of claim 12, wherein the purging system further comprises one or more adsorption chambers configured to receive at least a portion of the mixture from the purging heat exchanger, and wherein the one or more adsorption chambers are configured to separate the second refrigerant stream from the NCG by adsorbing the second refrigerant stream.

20. A heating, ventilation, air conditioning and refrigeration (HVAC & R) system comprising:

a refrigerant loop;

one or more adsorption chambers configured to receive the NCG from the purge heat exchanger, wherein the one or more adsorption chambers are configured to separate the NCG from remaining refrigerant.

21. The HVAC & R system of claim 20, wherein each of the one or more adsorption chambers comprises a modifying material configured to adsorb the remaining refrigerant and allow the NCG to pass through the one or more adsorption chambers.

22. The HVAC & R system of claim 21, wherein each of the one or more adsorbent chambers comprises a heater configured to heat the property-modifying material to expel the remaining refrigerant from the property-modifying material.

23. The HVAC & R system of claim 20, wherein the evaporator is configured to receive the remaining refrigerant from the one or more adsorption chambers.

24. The HVAC & R system of claim 20, wherein the one or more adsorbent chambers are configured to vent the NCG to the atmosphere.

25. The HVAC & R system of claim 20, wherein the purging system further comprises:

a pump configured to draw the NCG from the purge heat exchanger, wherein the one or more adsorption chambers are configured to receive the NCG from the pump;

a liquid pump configured to draw the first refrigerant flow from the evaporator;

a controllable expansion valve configured to receive the first refrigerant flow from the liquid pump and reduce a pressure of the first refrigerant flow; and

a purge coil of the purge heat exchanger configured to receive the first refrigerant flow from the controllable expansion valve; wherein the chamber of the purge heat exchanger enables the mixture to exchange heat with the first refrigerant flow within the purge coil.

26. The HVAC & R system of claim 25, wherein the purging system further comprises one or more thermoelectric assemblies configured to remove thermal energy from the first refrigerant stream exiting the liquid pump by converting an electrical power gradient to a thermal gradient.

27. A heating, ventilation, air conditioning and refrigeration (HVAC & R) system comprising:

a purge system configured to purge a vapor compression system of non-condensable gases (NCGs), the purge system comprising:

a pump configured to draw a mixture from a condenser of the vapor compression system, the mixture comprising vapor refrigerant and the NCG; and

a purge heat exchanger configured to receive the mixture from the pump and place the mixture in heat exchange relationship with a flow of refrigerant drawn from the vapor compression system to condense the vapor refrigerant in the mixture and separate the NCG from the vapor refrigerant in the mixture,

wherein the pump is configured to increase the pressure of the mixture to cause the NCG to flow from the purge heat exchanger to atmosphere via a pressure differential between the NCG and atmosphere.

28. The HVAC & R system of claim 27, comprising a liquid pump configured to draw the flow of refrigerant from the vapor compression system and provide the flow of refrigerant to the purge heat exchanger.

29. The HVAC & R system of claim 28, wherein the purge heat exchanger is a direct contact heat exchanger.

30. The HVAC & R system of claim 27, comprising an expansion device disposed along a conduit extending from a refrigerant loop of the vapor compression system to the purge heat exchanger, wherein the conduit and the expansion device are configured to supply the refrigerant flow to the purge heat exchanger.

31. The HVAC & R system of claim 30, wherein the expansion device is configured to reduce a pressure of the refrigerant stream to cause the refrigerant stream to flow through the purge heat exchanger and back to the vapor compression system via a second pressure differential between the refrigerant stream and an evaporator of the vapor compression system.

32. The HVAC & R system of claim 27, comprising an ejector configured to draw the flow of refrigerant from the purge heat exchanger and direct the flow of refrigerant to an evaporator of the vapor compression system.