KR100766157B1 - Vapor compression system and method - Google Patents

Abstract

The vapor compression system 10 includes an evaporator 16, a compressor 12 and a condenser 14 interconnected in a closed loop system. According to one embodiment, the multifunction valve 18 is configured to receive liquefied heat transfer fluid from the condenser 14 and hot steam from the compressor 12. The saturated steam line is sized to connect the outlet of the multifunction valve 18 to the inlet of the evaporator 16 and change the heat transfer fluid present in the multifunction valve 18 into saturated steam prior to delivery to the evaporator 16. . By detecting the temperature of the heat transfer fluid returning to the compressor 12 via the suction line 30 connecting the outlet of the evaporator 16 to the inlet of the compressor 12, the multifunction valve 18 transfers heat through the valve 18. Regulate the flow of fluid. The opening and closing separation passage in the multifunction valve 18 allows the steam compression system to operate in the defrost mode by flowing hot steam through the evaporator 16 and the saturated steam line 28 in the forward flow process, thereby defrosting the system. Reduces time and improves overall system performance

Description

Vapor Compression System and Method {VAPOR COMPRESSION SYSTEM AND METHOD}

The present invention relates to a vapor compression system, and more particularly to a machine controlled vapor compression system using a forward-flow defrost cycle.

In a closed loop vapor compression cycle, the heat transfer fluid releases heat and changes state from vapor to liquid, absorbs heat during evaporation and changes state from liquid to vapor in the evaporator. Conventional vapor compression vapor compression systems include a compressor for delivering a heat transfer fluid, such as freon, to a condenser, where heat is released as the vapor condenses into a liquid. The liquid flows through the liquid line to the thermal expansion valve, where the heat transfer fluid is volumetrically expanded. The heat transfer fluid exiting the thermal expansion valve is a low dry liquid vapor mixture. As used herein, the term “low dry liquid vapor mixture” refers to a low pressure heat transfer fluid in a liquid state with a small amount of flash gas, which cools the remaining heat transfer fluid when the heat transfer fluid continues to be supercooled. The expanded heat transfer fluid is then transferred to the evaporator, where the liquid refrigerant absorbs heat and evaporates at low pressure, changing its state from liquid to vapor. The heat transfer fluid, which is presently in the vapor state, is delivered rearward to the compressor via a suction line. Occasionally, the heat transfer fluid is discharged from the evaporator in superheated steam rather than steam.

In one aspect, the efficiency of the vapor compression cycle is determined by the system's ability to maintain the heat transfer fluid as a high pressure liquid upon exit from the condenser. The cooled high pressure fluid must remain liquid over a long refrigerant line extending between the condenser and the thermal expansion valve. Proper operation of the thermodynamic expansion valve depends on the volume of liquid heat transfer fluid passing through the valve. Since the high pressure liquid passes through the orifice of the thermal expansion valve, a pressure drop is formed in the fluid when the fluid is expanded through the valve. At low pressure, the fluid cools additional amounts in the form of small amounts of flash gas and cools most of the heat transfer fluid in liquid form. As used herein, the term "flash" refers to the pressure drop of an expansion valve, such as a thermal expansion valve, when some liquid passing through the valve rapidly changes to gas and cools the remaining heat transfer fluid in liquid form to a corresponding temperature. Gas "is used.

The low dry liquid vapor mixture is moved to the beginning of the cooling coil in the evaporator. As the fluid proceeds through the coil, it initially reaches a point where it absorbs a small amount of heat, the temperature of the fluid increases to a high temperature, and forms a high-dry liquid vapor mixture. As used herein, the term “dry liquid vapor mixture” refers to a heat transfer fluid that has a corresponding enthalpy and is present in the vapor and liquid states, and indicates that the temperature and pressure of the heat transfer fluid correlate with each other. The high dry liquid vapor mixture can absorb heat very efficiently because the high dry liquid vapor mixture is formed under state change conditions. The heat transfer fluid then absorbs heat from the environment and begins to boil. The boiling step in the evaporator coil forms saturated vapor in the coil and the boiling step continues to absorb heat from the environment. Once the fluid is completely boiled, the fluid is discharged as cold steam through the final stage of the cooling coil. When the fluid is completely converted to low temperature steam, the fluid absorbs very little heat. During the final stage of the cooling coil, the heat transfer fluid enters the superheated vapor state and forms as superheated steam. As defined herein, when a minimum amount of heat is added to the heat transfer fluid in the vapor state, the heat transfer fluid is formed as "superheated steam" and thus above the point at which the heat transfer fluid enters the gas state while maintaining a similar pressure. Raise the temperature of the fluid. The superheated steam is then returned through the suction line to the compressor, where the steam compression cycle is continued.

For high efficiency operation, the heat transfer fluid must change state from liquid to vapor through most of the cooling coils in the evaporator. When the state of the heat transfer fluid changes from liquid to vapor, the heat transfer fluid absorbs large amounts of energy because the molecules absorb the latent heat of evaporation and change from liquid to gas. On the other hand, a relatively small amount of heat is absorbed when the fluid is formed in the liquid or vapor state. Thus, the optimum cooling efficiency is determined by the precise control of the heat transfer fluid by the thermal expansion valve so that a change in the state of the fluid is formed at the largest possible cooling coil length. When the heat transfer fluid enters the evaporator in the cooling liquid state and exits from the evaporator in the vapor state or superheated vapor state, the cooling efficiency of the evaporator is lowered because most of the evaporator receives the fluid in a state that absorbs very little heat. For optimal cooling efficiency, most or all of the evaporator must contain fluid in the liquid and vapor phases. To achieve optimal cooling efficiency, the heat transfer fluid entering and exiting the evaporator must be a high dry liquid vapor mixture.

Thermodynamic expansion valves perform critical functions and regulate the transfer of heat transfer fluid through a closed loop system. Before any cooling effect occurs on the evaporator, the heat transfer fluid must be cooled by a pressure drop from the hot liquid exiting the condenser to a range suitable for the evaporation temperature. The flow of low pressure liquid entering the evaporator is regulated by a thermal expansion valve to maintain the maximum cooling efficiency of the evaporator. Typically, when the operation is stable, the mechanical thermal expansion valve regulates the flow of the heat transfer fluid by detecting the heat transfer fluid temperature of the suction line adjacent to the outlet of the evaporator. The heat transfer fluid on discharge from the thermostatic expansion valve is in the form of a low pressure liquid with a small amount of flash gas. The presence of the flash gas provides a cooling effect on the equilibrium of the heat transfer fluid in the liquid state, thus forming a low dry liquid vapor mixture. A temperature sensor is attached to the suction line to measure the amount of overheat the heat transfer fluid receives when the heat transfer fluid exits the evaporator. The amount of heat added to the steam after the heat transfer fluid is completely boiled and the liquid is no longer present in the suction line is superheated. Since a very small amount of heat is absorbed by the superheated steam, the thermodynamic expansion valve regulates the flow of heat transfer fluid to minimize the amount of superheated steam formed in the evaporator. Accordingly, the thermodynamic expansion valve determines the amount of low pressure liquid flowing to the evaporator by detecting the superheat degree of steam exiting the evaporator.

In addition to the need to regulate the flow of heat transfer fluid through the closed loop system, the optimum operating efficiency of the vapor compression system depends on the periodic defrost of the evaporator. Periodic defrosting of the evaporator is required to remove freezing formed in the evaporator coil during operation. When ice or frost forms on the evaporator, the ice or frost blocks the air passage of the evaporator coil. In commercial systems such as refrigerated display cabinets, air flow may be reduced to the extent that air curtains are not formed in the display cabinet due to increased frost. In commercial systems such as food refrigerators, it is necessary to defrost the evaporator every few hours. Various defrosting methods exist, such as the off-cycle method, in which the refrigeration cycle is stopped and the evaporator is defrosted by air at ambient temperature. In addition, an electric defrost off-cycle method is used, in which an electric heating element is constructed around the evaporator and a current flows in the heating coil to dissolve the frost.

In addition to off-cycle defrost systems, steam compression systems have been developed that use relatively high temperature heat transfer fluid exiting a compressor for defrosting an evaporator. In this technique, hot steam flows directly from the compressor to the evaporator. In one technique, the flow of hot steam is moved to the suction line and the system is operated in reverse. In another technique, hot steam flows into a dedicated line, which is directly connected from the compressor to the evaporator for the purpose of moving the hot steam for periodic defrosting of the evaporator. In addition, other complex methods have been developed that use various devices in vapor compression systems such as bypass valves, bypass lines, heat exchangers, and the like.

In order to achieve better operating efficiency compared to conventional steam compression steam compression systems, the refrigeration industry is developing more complex systems. Sophisticated computer controlled thermal expansion valves have been developed for better control of the heat transfer fluid through the evaporator. In addition, composite valves and piping systems have been developed to defrost the evaporator more quickly to maintain high heat transfer rates. The system can achieve some level of success, but the system cost increases significantly due to the increased complexity of the system. Therefore, there is a need for an efficient vapor compression system that can be installed at low cost and operated with high efficiency.

It is an object of the present invention to provide a vapor compression system which maintains high operating efficiency by flowing saturated steam into the inlet of the evaporator. As used herein, the term "saturated vapor" refers to a heat transfer fluid that is present in the vapor and liquid states with a corresponding enthalpy and indicates that the temperature and pressure of the heat transfer fluid correlate with each other. Saturated steam is a high temperature liquid vapor mixture. By flowing the saturated vapor into the evaporator, the liquid and vapor heat transfer fluid enters the evaporator coil. Thus, the heat transfer fluid flows to the evaporator in such a way that maximum heat can be absorbed by the fluid. In addition to high efficiency operation of the evaporator, according to one preferred embodiment of the present invention, the vapor compression system provides simple evaporator defrosting means. Multifunctional valves are used which receive the separation passages leading to the common chamber. In operation, the multifunction valve can deliver cooling saturated steam or defrost hot steam to the evaporator.

According to one aspect, the vapor compression system comprises an evaporator for evaporation of heat transfer fluid, a compressor for compression of heat transfer fluid at relatively high temperatures and pressures and a condenser for condensation of heat transfer fluid. The saturated steam line is connected from the expansion valve to the evaporator. According to one preferred embodiment of the present invention, the diameter and length of the saturated steam line is sufficient to change the heat transfer fluid to saturated steam before delivery of the fluid to the evaporator. According to one preferred embodiment of the present invention, the heat source is applied to the heat transfer fluid of the saturated vapor line and is sufficient for a portion of the heat transfer fluid to evaporate before the heat transfer fluid enters the evaporator. According to one preferred embodiment of the invention, a heat source is applied to the heat transfer fluid after the heat transfer fluid passes through the expansion valve and before the heat transfer fluid enters the evaporator. The heat source changes the heat transfer fluid from a low dry liquid vapor mixture to a high dry liquid vapor mixture or saturated steam. Typically, at least about 5% of the heat transfer fluid is evaporated before entering the evaporator. According to one embodiment of the invention, the expansion valve is configured in a multifunction valve, the multifunction valve comprising a first inlet for receiving the heat transfer fluid in a liquid state and a second inlet for receiving the heat transfer fluid in a vapor state. . The multifunction valve also includes a passage connecting the first inlet and the second inlet to the common chamber. A gating valve is configured in the passage, which allows the flow of heat transfer fluid to be stopped independently in each passage. Independent control of hot steam and saturated steam flow through the steam compression system results in increased operating efficiency due to increased heat transfer rate in the evaporator and rapid defrosting of the evaporator. The increased operating efficiency allows the vapor compression system to be filled with a relatively small amount of heat transfer fluid, and the vapor compression system can handle a relatively large amount of heat load.

1 is a schematic diagram of a vapor compression system arranged in accordance with an embodiment of the present invention.

Figure 2 is a partial side cross-sectional view showing a first side of a multifunction valve in accordance with an embodiment of the present invention.

3 is a partial side cross-sectional view showing a second side of the multifunctional valve shown in FIG.

4 is an exploded view of a multifunction valve in accordance with an embodiment of the present invention.

5 is a schematic diagram of a vapor compression system according to another embodiment of the present invention.

6 is an exploded view of a multifunctional valve according to another embodiment of the present invention.

7 is a schematic view of a vapor compression system according to another embodiment of the present invention.

8 is an enlarged cross-sectional view of a portion of the vapor compression system shown in FIG.

9 is a partial cross-sectional view schematically showing a recovery valve according to an embodiment of the present invention.

10 is a partial cross-sectional view schematically showing a recovery valve according to another embodiment of the present invention.

11 is a partial plan cross-sectional view of a valve body positioned over a multifunction valve or device in accordance with another embodiment of the present invention.

12 is a side view of the valve body of the multifunctional valve shown in FIG.

13 is an exploded view in partial cross-section of the multifunction valve or device shown in FIGS. 11 and 12;

14 is an enlarged view of a portion of the multifunction valve turning device shown in FIG. 12;

Figure 15 is a partial cross sectional view of a valve body constructed over a multifunction valve or device in accordance with another embodiment of the present invention.

16 is a schematic representation of a vapor compression system arranged in accordance with another embodiment of the present invention.

* Code Description *

10 .... Steam Compression Systems 12 ... Compressors

14 .... Condenser 16 .... Evaporator

18 .. Multifunctional valve 22 .. Liquid line

24 .... first entrance 26 .... second entrance

32 .... Temperature sensor 34 .... Control unit

36 .... Refrigerating case 54, 154 ... Valve assembly

An embodiment of a vapor compression system 10 arranged in accordance with an embodiment of the present invention is shown in FIG. 1. Compressor 12, condenser 14, evaporator 16 and multifunction valve 18 are included in vapor compression system 10. The compressor 12 is connected to the condenser 14 by a discharge line 20. The multifunction valve 18 is connected to the condenser by a liquid line 22 connected to the first inlet 24 of the multifunction valve 18. In addition, a multifunction valve 18 is connected to the outlet line 20 at the second inlet 26. A saturated steam line 28 connects the multifunction valve 18 to the evaporator 16, and a suction line 30 connects the outlet of the evaporator 16 to the inlet of the compressor 12. The temperature sensor 32 is mounted to the suction line 30 and operably connected to the multifunction valve 18. According to the invention, the compressor 12, the condenser 14, the multifunction valve 18 and the temperature sensor 32 are located inside the control unit 34. Thus, the evaporator 16 is located inside the refrigeration case 36. In a preferred embodiment of the present invention, the compressor 12, the condenser 14, the multifunction valve 18, the temperature sensor 32 and the evaporator 16 are all located inside the refrigeration case 36. In a preferred embodiment of the present invention, the vapor compression system has a control unit 34 and a refrigeration case 36, a compressor 12 and a condenser 14 located within the control unit 34, and an evaporator 16. ), The multifunction valve 18 and the temperature sensor 32 are located inside the refrigeration case 36.

For example, azeotropic mixed refrigerants consisting of R-12 of dichlorodifluoromethane and R-22, R-12 and R-152a of monochlorodifluoromethane, R-500 and R-23. And essentially and commercially available heat transfer, including refrigerants such as chlorofluorocarbons such as azeotropic mixed refrigerants R-503, R-22 and R-115, azeotropic mixed refrigerants consisting of R-13 and R-502. Fluids can be used in the vapor compression system of the present invention. Refrigerants not limited to, for example, R-13, R-113, 141b, 123a, 123, R-114 and R-11 may also be used as hydrochlorofluorocarbons, R-134a, 134, 152, 143a, Refrigerants such as hydrofluorocarbons such as 125, 32, and 23 and azeotrope HFCs such as AZ-20 and AZ-50 (commonly known as R-507) can be used in the vapor compression system. . Mixed refrigerants (commonly known as R-404a) such as MP-39, HP-80, FC-14, R-717 and HP-62 can be used as refrigerants in the vapor compression system of the present invention. Thus, according to the present invention, the specific refrigerant or combination of refrigerants used in the present invention can be operated with a greater system efficiency by virtually all refrigerants than prior art vapor compression systems using the same refrigerant. It is not considered important in terms of operation.

In operation, compressor 12 compresses the heat transfer fluid to a relatively high pressure and temperature. The temperature and pressure at which the heat transfer fluid is compressed by the compressor 12 depends on the specific size of the vapor compression system 10 and the cooling load requirements of the system. The compressor 12 pressurizes the heat transfer fluid into the discharge line 20 and the condenser 14. Referring to the following detailed description, the second inlet 26 is closed during the cooling operation, and the total output of the compressor 12 is pressurized through the condenser 14.

In the condenser 14 a medium such as water air or a second refrigerant is injected past the coils in the condenser, and the pressurized heat transfer fluid changes the liquid state. Since the latent heat in the fluid is released during the condensation process, the temperature of the heat transfer fluid drops to about 10 to 40 ° F. (5.6 to 22.2 ° C.), depending on the specific heat transfer fluid or glycol. Condenser 14 discharges the liquefied heat transfer fluid to liquid line 22. Referring to FIG. 1, the liquid line 22 is discharged directly into the multifunction valve 18. Since the liquid line 22 is relatively short in length, the liquid line 22 moves from the condenser 14 to the multifunction valve 18. The temperature of the liquid carried by (22) and under pressure is not increased. Short liquid lines are advantageously delivered by the vapor compression system 10. Since the fluid does not travel a significant distance when the fluid is converted to a high pressure liquid, the heat absorption capacity is not lost by inadvertent heating of the liquid or loss of liquid pressure before the liquid enters the multifunction valve 18. In the above embodiment of the present invention, the vapor compression system uses the relatively short liquid line 22, when referring to the following description, the vapor compression system uses the relatively long liquid line 22 of the present invention. Advantages can be obtained. The heat transfer fluid discharged by the condenser 14 enters the multifunction valve 18 at the first inlet 24 and undergoes volume expansion at a rate determined by the temperature of the suction line 30 at the temperature sensor 32. . The multi-function valve 18 discharges heat transfer fluid into the saturated steam line 28 as saturated steam. The temperature sensor 32 transmits the temperature information to the multifunctional valve 18 through the control line 33.

Those skilled in the art will appreciate that the vapor compression system 10 can be used in a variety of ways to control the temperature of a container, such as a refrigerated case, in which perishable foods are stored. For example, when the steam compression system 10 is used to control the temperature of a refrigeration case with a cooling load of about 12000 Btu / hr (84 g cal / s), it is from about 110 ° F. (43.3 ° C.) to about 120 ° F. A temperature of (48.9 ° C.) and a pressure of about 1501bs / in ² (1.03E 5 N / m 2) to about 180 1bs / in ² (1.25 E5 N / m 2) are released by the compressor 12.

According to a preferred embodiment of the present invention, the size of the saturated steam line 28 is changed so that the low pressure fluid discharged into the saturated steam line 28 is converted into the saturated steam as it moves through the saturated steam line 28. It is decided. In one embodiment, the saturated steam line 28 is sized to handle from about 2500 ft / min (76 m / min) to about 3700 ft / min (1128 m / min) of heat transfer fluid, such as R-12, It has a diameter of about 0.5 to 1.0 inch (1.27 to 2.54 cm) and a length of about 90 to 100 feet (27 to 30.5 m). Referring to the description below, the multifunction valve 18 includes a common chamber just in front of the outlet. Additional volume expansion occurs as heat transfer fluid enters the common chamber. Additional volume expansion of the heat transfer fluid within the common chamber of the multifunction valve 18 is equivalent to increasing the line by about 225% of the saturated steam line 28. Do. It is understood by those skilled in the art that the positioning of the valve for volume expansion of the thermal expansion fluid in a position proximate to the condenser and for the significant distance of the fluid line between the volume expansion position and the evaporator is quite different from prior art systems. In a typical prior art, the expansion valve is located directly in proximity to the inlet of the evaporator, and if a temperature sensing device is used, the device is mounted in a position very close to the outlet of the evaporator. Referring to the above description, the efficiency of the system is low because the actual amount of evaporator is liquid rather than saturated steam. Variations in high side pressures, liquid temperatures, heat loads or other conditions can adversely affect the efficiency of the evaporator.

Compared with the prior art, the steam compression system according to the present invention allows a labeled steam line to be positioned between the volume expansion and the inlet of the evaporator so that a portion of the heat transfer fluid is transferred to the saturated steam before the heat transfer fluid enters the evaporator. Is converted. When the evaporator 16 is filled with saturated steam, the cooling efficiency is considerably increased. Increasing the cooling efficiency of an evaporator, such as evaporator 16, the vapor compression system provides a number of advantages. For example, the amount of heat transfer fluid for controlling the air temperature of the refrigerating case 36 to the required degree is reduced. Further, the power supply amount of the compressor 12 is reduced, so that the running cost is reduced. The compressor 12 may also be configured smaller in size than prior art systems that handle similar cooling loads. In addition, in a preferred embodiment of the present invention, the construction of a plurality of parts in the vicinity of the evaporator is avoided by the vapor compression system. By limiting the number of components inside the refrigeration case 36 to a minimum, the heat load of the refrigeration case 36 is minimized.

In this embodiment of the present invention, when the multifunction valve 18 is placed in proximity to the condenser 14, as a result of forming a relatively short liquid line 22 and a relatively long saturated steam line 28, Even if the multifunction valve 18 is placed in the immediate vicinity of the inlet of the evaporator 16, the relatively long liquid line 22 and the relatively short saturated steam line 28 are formed, the advantages of the present invention can be obtained. Can be. For example, in a preferred embodiment, referring to FIG. 7, the multifunction valve 18 is located directly adjacent the inlet of the evaporator 16, resulting in a relatively long liquid line 22 and a relatively short saturated steam. Line 28 is formed. 7 and 8, a heat source 25 is attached to the saturated steam line 28 so that the heat transfer fluid entering the evaporator 16 is saturated steam. A temperature sensor 32 is mounted to the suction line 30 and operably connected to the multifunction valve 18 and heat source 25 to evaporate a portion of the heat transfer fluid before the heat transfer fluid enters the evaporator 16. This strength is enough. The heat transfer fluid flowing into the evaporator 16 is converted into saturated steam, and referring to FIG. 8, a part of the heat transfer fluid is present in the liquid state 29 and another part of the heat transfer fluid is present in the vapor state 31. .

The heat source 25 for evaporating a portion of the heat transfer fluid forms heat transferred to the surroundings from the condenser 14, for example heat transferred to the surroundings from the discharge line 20, heat transferred to the surroundings from the compressor, The heat source 25 is generated by an external or internal heat source known to those skilled in the art, such as heat generated by a compressor, heat generated using a heat combustible material generated from an electric heat source, heat generated using solar energy or other heat sources. Can be formed. The heat source 25 may also consist of an active heat source such as a heat source intentionally attached to a portion of the vapor compression system 10, such as saturated steam line 28. Heat sources such as, but not limited to, heat generated from an electrical heat source, heat generated using combustible materials, heat generated using solar energy or other heat sources intentionally and actively attached to a portion of the vapor compression system 10 are active. Included in the heat source. Due to poor thermal insulation or for other reasons, the heat source formed by heat that accidentally leaks into part of the vapor compression system 10 and heat that is accidentally or unknowingly absorbed into all parts of the vapor compression system 10 is not an active heat source.

In a preferred embodiment of the present invention, referring to FIG. 8, the temperature sensor 32 exits the evaporator 16 such that a portion of the heat transfer fluid exits the evaporator 16 such that it is in a liquid state 29. To monitor the heat transfer fluid. In a preferred embodiment of the invention, at least about 5% of the heat transfer fluid is vaporized before the heat transfer fluid enters the evaporator and at least about 1% of the heat transfer fluid is in the liquid state when exiting the evaporator. When part of the heat transfer fluid is in the liquid state 29 and the vapor state 31 when entering or exiting the evaporator, the evaporator 16 is operated at maximum efficiency by the vapor compression system of the present invention. In a preferred embodiment of the invention, the heat transfer fluid is at least about 1% superheated when it exits the evaporator 16. In a preferred embodiment of the invention, the heat transfer fluid is between about 1% liquid and about 1% superheated steam when it exits the evaporator 16.

While the embodiments depend on the size and dimensions of the heat source 25 or the saturated steam line 28 such that the heat transfer fluid enters the evaporator 16 as saturated steam, when entering the evaporator 16, the heat transfer fluid is introduced. Any means that can be converted to saturated steam and known to those skilled in the art can be used. Further, while the above embodiments use the temperature sensor 32 to monitor the state of the heat transfer fluid exiting the evaporator, such as a pressure sensor or a sensor that measures the strength of the fluid, Determination and known measuring devices known to those skilled in the art can be used. Further in the above embodiments, while the state of the heat transfer fluid exiting the evaporator 16 is monitored by the measuring device, in order to monitor the state of the heat transfer fluid at all positions around or inside the evaporator 16, The measuring device can be arranged at all positions around or inside the evaporator 16.

Referring to FIG. 12, an embodiment of the multifunction valve 18 is shown in partial side cross-sectional view. The heat transfer fluid first enters the inlet 24 and moves across the first passage 38 to the common chamber 40. An expansion valve 42 is located within the first passage 38 proximate the first inlet 24. The expansion valve 42 measures the flow of heat transfer fluid through the first passage 38 by a diagram contained within the upper valve housing 44 (not shown in the figure). Any device known to those skilled in the art that can be used to measure the flow of heat transfer fluid, such as a thermostatic expansion valve, capillary tube or pressure controller, can be configured as expansion valve 42. The control line 33 is connected to an input 62 located on the upper valve housing 44. Signals transmitted through the control line 33 actuate the diagram inside the upper valve housing 44. The valve assembly 54 (shown in FIG. 4) is actuated by a diagram to control the amount of heat transfer fluid entering the expansion valve 52 (shown in FIG. 4) from the first inlet 24. A first gating valve 46 is positioned within the first passage 38 adjacent to the common chamber 40. In a preferred embodiment of the present invention, a solenoid valve capable of determining the flow of heat transfer fluid passing through the first passage in response to the electrical signal is configured as the second gating valve 46.

Referring to FIG. 3, the second side of the multifunction valve 18 is shown as a partial side cross-sectional view. The second passage 48 connects the second inlet 26 to the common chamber 40. The second gating valve 50 is positioned in the second passage 48 adjacent to the common chamber 40. In a preferred embodiment of the present invention, a solenoid valve capable of determining the flow of heat transfer fluid passing through the second passage when receiving an electrical signal is configured as the second gating valve 50. The common chamber 40 discharges heat transfer fluid from the multifunction valve 18 through the outlet 41.

Referring to FIG. 4, an exploded perspective view of the multifunction valve 18 is shown. The expansion valve 42 includes an expansion chamber 52 proximate the first inlet 24, the valve assembly 54, and the upper valve housing 44. The valve assembly 54 is actuated by a diagram contained within the upper valve housing 44 (not shown). First and second tubes 56 and 58 are positioned at intermediate positions of the expansion chamber 52 and the valve body 60. Gating valves 46 and 50 are mounted on the valve body 60. According to the present invention, by closing the first gating valve 46 and opening the second gating valve 50, the steam compression system 10 can be operated in the defrost mode. In the defrost mode, a high temperature heat transfer fluid flows into the second inlet 26, passes through the second passage and into the common chamber 4. Hot steam is released through outlet 41 and travels from saturated steam line 28 to evaporator 16. Sufficient temperature is formed in the hot steam to raise the temperature of the evaporator 16 to about 50-120 ° F. (27.8-66.7 ° C.). The temperature rise is sufficient to remove frost from the evaporator 16 and restore the heat transfer rate to the required operating level.

While the multifunction valve 18 is used in the above embodiments to expand the heat transfer fluid before it enters the evaporator, the expansion valve 42 or even the recovery valve () may be used so that the heat transfer fluid expands before entering the evaporator 16. Thermostatic expansion valves or throttling valves such as 19 may be used.

In a preferred embodiment of the present invention, the heat transfer fluid is passed from the low quality liquid vapor mixture to the high dry liquid vapor mixture or saturated steam after the heat transfer fluid passes through the expansion valve 42 and the heat transfer fluid is evaporator ( Prior to entering the inlet of 16, a heat source 25 is attached to the heat transfer fluid.

In a preferred embodiment of the present invention, a heat source 25 is attached to the multifunction valve 18. Referring to FIG. 9, in another preferred embodiment of the present invention, a heat source 25 is attached inside the recovery valve 19. A first inlet 124 connected to the liquid line 22 and a first outlet 159 connected to the saturated steam line 28 are configured in the recovery valve 19. The heat transfer fluid flows from the first inlet 124 of the recovery valve 19 to the common chamber 140. An expansion valve 142 is positioned proximate to the first inlet 124 such that the heat transfer fluid entering the first inlet 124 expands from the liquid state into a low dry liquid vapor mixture. The second inlet 127 is connected to the discharge line 20, and receives the high temperature heat transfer fluid flowing out of the compressor 12. The high temperature heat transfer fluid exiting the compressor 12 flows into the second inlet 127 and moves across the second passage 123. The second passage 123 is connected to the second inlet 127 and the second outlet 130. A portion of the second passage 123 is located close to the common chamber 140.

As the high temperature heat transfer fluid approaches the common chamber 140, heat generated from the high temperature heat transfer fluid is transferred from the second passage 123 to the common chamber 14 in the form of a heat source. When heat is applied from the heat source 125 to the heat transfer fluid, as the heat transfer fluid flows through the common chamber 14, the heat transfer fluid inside the common chamber 14 is converted from a low dry liquid vapor mixture to a high dry liquid vapor mixture. do. In addition, as the high temperature heat transfer fluid passes near the common chamber 14, the high temperature heat transfer fluid located inside the second passage is cooled. As it travels across the second passage, the cooled, high temperature heat transfer fluid exits the second outlet 130 and enters the condenser 14. As a high dry liquid vapor mixture or saturated steam, the heat transfer fluid in the common chamber 14 flows out of the recovery valve 19 into the saturated steam line 28 at the first outlet 159.

In a preferred embodiment, the heat source 125 is constituted by heat transferred from the compressor to the outside, for example, heat generated from an electrical heat source, heat generated using combustible materials, and generated using solar energy. As with heat or other heat sources, heat sources 125 may be constructed by internal or external heat sources known to those skilled in the art. In addition, referring to the above description, the heat source 125 may be configured by all the heat sources 25 and the active heat sources.

In a preferred embodiment of the present invention, a third passage 148 and a third inlet 128 are configured in the recovery valve 19. The third inlet 128 is connected to the discharge line 20 and receives the high temperature heat transfer fluid discharged from the compressor 12. A first gating valve 46 (not shown), which can block the flow of heat transfer fluid through the common chamber 14, is located close to the first inlet 124 of the common chamber 14. The third inlet 128 is connected to the common chamber 14 by the third passage 148. The second gating valve 50 (not shown) is located in the third passage 148 located close to the common chamber 14. In a preferred embodiment of the present invention, the second gating valve 50 is a solenoid valve capable of blocking the flow of the heat transfer fluid through the third passage 148 when receiving an electrical signal.

According to the present invention, the second gating valve closes the first gating valve 46 located near the first inlet 124 of the common chamber 14 and is located in the third passage 148 close to the common chamber 14. By opening 50, the vapor compression system 10 can be operated in the defrost mode. In the defrost mode, a high temperature heat transfer fluid flows from the compressor 12 into the third inlet 128 and moves across the third passage 138 and into the common chamber 14. The high temperature heat transfer fluid is discharged through the first outlet 159 of the recovery valve 19 and moves across the saturated steam line 28 to the evaporator 16. The high temperature heat transfer fluid has a temperature sufficient to raise the temperature of the evaporator 16 to about 50-120 ° F. (27.8-66.7 ° C.). The temperature is sufficient to remove frost from the evaporator 16 and restore the heat transfer rate to the required operating level.

During the defrost cycle, the oil pockets entrapped within the system are moved and heated in the same direction as the heat transfer fluid. When the hot gas is pressurized through the system in the forward flow, the hung oil is eventually returned to the compressor. Hot gases travel relatively fast through the system and reduce cooling time, improving defrosting efficiency. The forward flow defrosting method according to the present invention provides a number of advantages over the reverse flow defrosting method. For example, the reverse flow defrost system uses a small diameter check valve close to the inlet of the evaporator. The valve valve limits the hot gas flow in the reverse direction, reducing the flow rate and consequently the defrosting efficiency. In addition, the pressure increase in the system during the defrosting operation is avoided by the forward flow defrosting method according to the present invention. In addition, oil trapped inside the system by the reverse flow method is pressurized into the expansion valve. This causes excessive oil inside the expansion valve to cause a gumming action to limit the operation of the valve. Also, forward defrosting does not reduce the liquid line pressure inside additional refrigeration circuits operated in addition to the defrost circuit.

Steam compression systems arranged in accordance with the present invention can be operated with less heat transfer fluid than systems of comparable size and according to the prior art. By placing the multifunction valve in close proximity to the condenser rather than the evaporator, saturated steam lines are filled with a relatively low density of vapor rather than a relatively high density of liquid. Optionally, by attaching a heat source to the saturated steam line, a relatively low density vapor is packed into the saturated steam line rather than a relatively high density liquid. In addition, by supplying sufficient steam to enhance the suitable head pressure in the expansion valve, prior art systems compensate for low temperature ambient operation (eg winter). In a preferred embodiment of the present invention, since the multifunction valve is located in close proximity to the condenser, the thermal pressure of the vapor compression system is more easily maintained in cold weather.

The forward flow defrosting capability of the present invention improves the defrosting efficiency and provides a number of operational advantages. For example, pressurizing jammed oil with a compressor avoids slugging of the liquid and consequently increases the service life of the device. Also, because the time for defrosting the system is reduced, the operating cost is reduced. Since the flow of hot gas is stopped quickly, the system can be quickly returned to normal cooling operation. When frost is removed from the evaporator 16, the temperature increase of the heat transfer fluid inside the suction line 30 is detected by the temperature sensor 32. When the temperature rises to a predetermined set temperature, the second gating valve 50 and the multifunction valve 18 are closed. Once the flow of heat transfer fluid is resumed through the first passage 38, the saturated saturated steam is quickly returned to the evaporator 16 to resume the cooling operation.

It is understood by those skilled in the art that a number of modifications may be provided to enable the vapor compression system of the present invention to have a variety of applications. For example, steam compression systems that typically operate in retail food stores include a number of refrigeration cases that can be provided by an ordinary compressor system. In applications where refrigeration must be performed at high heat loads, multiple compressors can be used to increase the cooling capacity of the vapor compression system.

A vapor compression system 64 according to another embodiment of the present invention with multiple evaporators and multiple compressors is shown in FIG. 5. In accordance with the present invention, multiple compressors, condensers and multiple multifunction valves are included within the control unit 66 while maintaining operating efficiency and low cost advantages. Saturated steam lines 68 and 70 feed saturated steam from control unit 66 to respective evaporators 72 and 74. An evaporator 72 is located inside the first refrigeration case 76 and an evaporator 74 is located inside the second refrigeration case 78. The first and second refrigeration cases 76 and 78 may be located close to each other or optionally at a relatively long distance from each other. The exact positioning depends on the particular application. For example, within a retail food store, refrigeration cases are typically located close to each other along the aisle. The vapor compression system of the present invention can be adapted to various operating environments. This advantage is obtained because, in part, the number of components located within each refrigeration case is minimal. In a preferred embodiment of the present invention, a vapor compression system can be used in a location where the occupied space is minimal, avoiding the requirement of arranging multiple system components in close proximity to the evaporator. This feature is particularly advantageous for retail activities that often have limited floor space.

In operation, heat transfer fluid is supplied by multiple compressors 80 within output manifold 82 connected to discharge line 84. The first branch line 88 connected to the first multifunction valve 90 and the second branch line 92 connected to the second multifunction valve 94 are included in the discharge line 84, and the discharge line 84 is included in the discharge line 84. Feeds from the condenser 86 to the first and second multifunction valves 90 and 94. Saturated steam line 68 connects the first multifunction valve 90. Evaporators 72 and 74 are connected to a collection manifold 100 which is supplied with a plurality of compressors 80 by a bifurcated suction line 98. A temperature sensor 102 is connected to the suction line 98. Is positioned on the first segment 104 of the signal and transmits signals to the first multifunction valve 90. The temperature sensor 106 is located on the second segment 108 of the suction line 98 and transmits signals to the second multifunction valve 94. In a preferred embodiment of the present invention, a heat source such as heat source 25 may be attached to saturated steam lines 68, 70 such that heat transfer fluid enters evaporators 72 and 74 as saturated steam.

It is understood by those skilled in the art that many modifications and variations of the vapor compression system 64 may be configured to account for different refrigeration applications. For example, two or more evaporators may be added to the system according to the general method shown in FIG. 5. Also in order to further increase the cooling capacity, more condensers and more compressors can be included in the vapor compression system.

A multifunctional valve 110 arranged in accordance with another embodiment of the present invention is shown in FIG. 6. Similar to the multifunctional valve embodiment of the prior art, heat transfer fluid exiting the condenser in the liquid state enters the first inlet 122 and expands inside the expansion chamber 152. The flow of the heat transfer fluid is measured by the valve assembly 154. In an embodiment of the present invention, an armature 114 extending into the common mounting area 116 is configured in the solenoid valve 112. In the refrigeration mode, the amateur 114 extends to the bottom of the mounting area 116, and cold refrigerant flows through the passage 118 to the outlet 120 after the common chamber 140. In the defrost mode, hot steam enters the second inlet 126 and moves through the common mounting region 116 to the outlet 120 after the common chamber 140. Since the gating valve is designed to control the flow of hot steam and cooling steam through a single gating valve, a reduced number of components are included in the multifunction valve 110.

In another embodiment of the present invention, the flow of liquefied heat transfer fluid from the liquid line through the multifunction valve is controlled by a check valve inside the first passage to open and close the flow of liquefied heat transfer fluid into the saturated steam line. Can be. The flow of heat transfer fluid is controlled through the vapor compression systems by means of a pressure valve located in the suction line close to the inlet of the compressor. Thus, by means of separate parts at different positions within the vapor compression system, various functions of the multifunctional valve according to the invention can be performed. All such variations and modifications are contemplated in the present invention.

It is understood by those skilled in the art that the vapor compression system and method can be implemented in a variety of configurations. For example, the compressor, condenser, multifunction valve and evaporator can all be housed in a single unit and arranged in a walk-in cooler. In this application, an ambient structure outside the cooler is used to make a protruding structure through the walls of the walk-in cooler and to condense the heat transfer fluid.

In another application, the vapor compression system and method of the present invention can be configured for home or business air conditioning. In this application, ice formation of the evaporator is generally not a problem, so defrost cycles are unnecessary.

In another application, a vapor compression system according to the invention can be used to cool the water. In this application the evaporator is submerged into the cooled water. Optionally, water may be pressurized through tubes forming a mesh structure with the evaporator coils.

In another application, the vapor compression system and method according to the present invention may be constructed in a cascade with another system to create an extremely low refrigeration temperature. For example, two systems using different heat transfer fluids may be coupled together such that the evaporator of the first system provides a low temperature ambient. The condenser of the second system is arranged inside the cold ambient environment and is used to condense the heat transfer fluid in the second system.

Another embodiment of the multifunction valve or device 225 is shown in FIGS. 11-14. The embodiment is functionally similar to the multifunction valve 18 described in FIGS. 2 to 4 and 6. Referring to the drawings, the main body or housing 226, which is preferably configured as a unitary structure having a pair of threads 227 and 228 with a screw structure, is included in the embodiment, and in Fig. 13 the bosses are a pair of gating valves ( 229) and color assemblies.

The assembly includes a solenoid actuated gating valve containing a threaded collar 230, a gasket 231 and a member 232 having a central hole 233 and a needle valve element 236, the holes being reciprocating. Receive a movable valve pin 234, the valve pin including a spring 235, and the needle valve element 236 into a hole 237 of the valve seat member 238 having an elastic seal 239. ) Is accommodated and the size of the elastic seal is determined to be received in a sealed state within the cavity 240 of the housing 226. In the groove 242 of the valve seat member 238, the valve seat member 241 is accommodated in a fitted state. The valve seat member 241 includes a hole 243 that operates with the needle valve element 236 to control the refrigerant flow.

The first inlet 244 (corresponding to the first inlet 24 in the previously described embodiment) receives the liquid supply refrigerant from the expansion valve 42 and the second inlet 26 (in the previously described embodiment). A second inlet 245 receives hot gas from the compressor 12 during the defrost cycle. In a preferred embodiment, referring to FIG. 16, a first inlet 244, an outlet 248, a common chamber 246, and an expansion valve 42 are configured in the multifunction valve 225. In a preferred embodiment, expansion valve 42 is connected to first inlet 246. The common chamber 246 (corresponding to the common chamber 40 in the previously described embodiment) is included in the housing 226. Refrigerant passing through the inlet 244 into the semicircular cavity 247 is received from the condenser 14 to the expansion valve 42 and when the gating valve 229 is opened, the refrigerant is in the common chamber 246. And exit from the multifunction valve 225 through the outlet (corresponding to the outlet 41 in the previously described embodiment).

Referring to FIG. 11, a first passageway 249 (corresponding to the first passageway 38 in the previously described embodiment) is included in the housing 226, the first passageway being defined by the common chamber 246. It works with the inlet 244. Similarly, the second passage 250 (corresponding to the second passage 48 in the previously described embodiment) acts with the second inlet 245 by the common chamber 246.

With regard to the operation of the multifunction valve 225 or apparatus, reference is made to the above description, as the components operate in the same way during the refrigeration cycle and the defrost cycle. In a preferred embodiment, the heat transfer fluid exits the condenser 14 and passes through the expansion valve 42 in a liquid state. As the heat transfer fluid passes through expansion valve 42, the heat transfer fluid changes from liquid to liquid vapor mixture. The heat transfer fluid enters the first inlet 244 as a liquid vapor mixture and expands inside the common chamber 246. In a preferred embodiment, the heat transfer fluid expands in a direction away from the flow of the heat transfer fluid. As the heat transfer fluid expands into the common chamber 246, the liquid separates from the vapor in the heat transfer fluid. The heat transfer fluid then flows out of the common chamber 246. Preferably, the heat transfer fluid, as liquid and vapor, flows out of the common chamber 246, and the actual amount of liquid is separated from the actual amount of steam. The heat transfer fluid then moves to evaporator 16 via saturated steam line 28 passing through outlet 248. Referring to the description below, in a preferred embodiment, the heat transfer fluid then passes through the outlet 248 and enters the evaporator 16 at the first evaporation line 328. The heat transfer fluid moves from the outlet 248 to the inlet of the evaporator 16 as liquid and vapor, and the actual amount of liquid is preferably separated from the actual amount of steam.

In a preferred embodiment a pair of gating valves 229 may be used to control the flow of heat transfer fluid or hot steam into the common chamber 246. In the refrigeration mode, a gating valve 229 on one side is opened to allow refrigerant to flow through the first inlet 244 into the common chamber 246 and then to the outlet 248. In the defrost mode, the other side gating valve 229 is opened so that the hot steam can flow into the common chamber 246 through the second inlet 245 and to the outlet 248. While the multifunction valve 225 is described as multiple gating valves 229 in the above embodiments, the multifunction valve 225 may consist of only one multifunction valve. In addition, the multifunction valve 225 is described as having a second inlet 245 so that hot steam can flow during the defrost mode, and the multifunction valve 225 is designed to have only the first inlet 244.

In a preferred embodiment, referring to FIG. 15, the multifunction valve has a bleed line. The bleed line 251 is connected to the common chamber, and the heat transfer fluid inside the common chamber 246 is preferred by the bleed line. In the preferred embodiment, the liquid separated from the liquid vapor mixture flowing into the heat transfer fluid is a bleed line ( 251, it may be moved to the saturated steam line 28 or the first evaporation line 328. The bleed line 251 is connected to the bottom surface 252 of the common chamber 246, and the surface of the common chamber 246 located closest to the ground is preferably formed by the bottom surface 252.

In a preferred embodiment, the dimensions of the multifunction valve 225 are determined in Table A and the multifunction valves are shown in FIGS. 11-14. The length of the common chamber 246 is defined as the distance from the outlet 248 to the rear wall 253. Referring to FIG. 11, the length G of the common chamber 246 is shown. Referring to FIG. 11, the common chamber 246 has a first portion proximate the second portion, the first portion beginning at the outlet 248 and the second portion ending at the rear wall 253. First inlet 244 and outlet 248 are connected with the first portion. The heat transfer fluid is introduced into the first part of the common chamber 246 through the first inlet 244.

In a preferred embodiment, the length of the first portion corresponds to only about 75% of the length of the common chamber 246. More preferably, the length of the first portion corresponds to only about 35% of the length of the common chamber 246.

Table A

Size of the multifunction valve

Size inch millimeters

Not specifically mentioned not specifically mentioned

All dimensions are +/- 0.015 All dimensions are +/- 0.015

Should be. Should be.

A 2.500 63.5

B 2.125 53.975

C 1.718 43.637

D1 (diameter) 0.812 20.625

D2 (diameter) 0.609 15.469

D3 (diameter) 1.688 42.875

D4 (Diameter) 1.312 (+/- 0.002) 33.325 (+/- 0.051)

D5 (diameter) 0.531 13.487

E 0.406 10.312

F 1.062 26.975

G 4.500 114.3

H 5.000 127                 

I 0.781 19.837

J 2.500 63.5

K 1.250 31.75

L 0.466 11.836

M 0.812 (+/- 0.005) 20.6248 (+/- 0.127)

R1 (radius) 0.125 3.175

In a preferred embodiment, referring to FIG. 16, heat transfer fluid passes through expansion valve 42 and then enters the inlet of evaporator 16. In the above embodiment, the first evaporation line 328, the evaporator coil 21, and the second evaporation line 330 are configured in the evaporator 16. Referring to FIG. 16, a first evaporation line 328 is located between the outlet 248 and the evaporator coil 21. The second evaporation line 330 is located between the evaporator coil 21 and the temperature sensor 32. Evaporator coils are any coil or device of the prior art that absorbs heat. The multifunction valve 18 is connected to and closely connected to the evaporator 16. In a preferred embodiment, referring to FIG. 16, a first inlet 244, a portion of a multifunction valve 18 such as outlet 248, and a common chamber 246 and evaporator 16 are configured. Expansion valve 42 is located close to evaporator 16. The heat transfer fluid exits the expansion valve 42 and then directly enters the evaporator 16 at the inlet 244. When the heat transfer fluid exits the expansion valve 42 and enters the evaporator 16 at the inlet 244, the temperature of the heat transfer fluid is the evaporation temperature, that is, the heat transfer fluid absorbs heat at the moment passing through the expansion valve 42. To start.

When passing through the common chamber 246, the outlet 248 and the inlet 244, the heat transfer fluid enters the first evaporation line 328. The first evaporation line 328 is preferably insulated. The heat transfer fluid then flows out of the first evaporation line 328 and enters the evaporation coil 21. When the evaporation coil 21 flows out, a heat transfer fluid flows into the second evaporation line 330. The heat transfer fluid is present in the second evaporation line 330 and the evaporator 16 at the temperature sensor 32.

It is preferred that all elements within the evaporator 16, such as saturated steam line 28, multifunction valve 18 and evaporator coil 21, absorb heat. In a preferred embodiment, as the heat transfer fluid passes through the expansion valve, there is a temperature of the heat transfer fluid within 20 ° F. which is the temperature of the heat transfer fluid inside the evaporator coil 21. In a preferred embodiment, the heat transfer fluid temperatures of all the elements inside the evaporator 16, such as the saturated steam line 28, the multifunction valve 18 and the evaporator coil 21, are such that the other elements inside the evaporator 16 are heat transfer fluids. The temperature is within 20 ° F.

As is known to those skilled in the art, all of the above elements of the vapor compression system 10, such as evaporator 16, liquid line 22 and suction line 30, can have a size and scale to meet various load requirements.

In a preferred embodiment, the refrigerant charge amount of the heat transfer fluid inside the vapor compression system 10 is greater than or equal to the refrigerant charge amount of the prior art.

Without further attempt, the foregoing description will enable those skilled in the art to make the best use of the present invention. The following examples merely illustrate the invention and in no case limit the spirit of the invention.

The multifunction valve inside the refrigerating circuit is mounted on a 5-ft (1.52 m) Tyler Chest Freezer, and a standard expansion valve is connected to the bypass line so that the refrigerating circuit is a prior art steam compression system and the XDX of the present invention. It can be operated as a vapor compression system. A saturated steam line with a tube outer diameter of about 0.375 inches (0.953 cm) and an effective tube length of about 10 ft (3.048 m) is mounted to the refrigeration circuit. The refrigeration circuit is powered by Copeland's hermetic compressor, which has a capacity of about one-third freeze tone (338 kg). A sensing valve is attached to the suction line about 18 inches from the compressor. The R-12 refrigerant, available from DuPont, is filled into the circuit by approximately 28 oz (792 g). A bypass line, which extends from the compressor discharge line to the saturated steam line, is mounted in the refrigeration circuit for the forward flow defrost function. All cooling ambient air temperature readings are obtained using the "CPS Date Logger" by a CPS temperature sensor located approximately 4 inches (10 cm) from the floor and located in the center of the refrigeration case.

XDX System-Medium Temperature Operation.

The nominal operating temperature of the evaporator is 20 ° F (-6.7 ° C) and the nominal operating temperature of the condenser is 120 ° F (48.9 ° C). The freezer load of the evaporator is about 3000 Btu / hr (21 g cal / s). The multifunction valve measures refrigerant flowing into the saturated steam line at about 20 ° F. (-6.7 ° C.). A sensing valve is set to maintain approximately 25 ° F. (13.9 ° C.) to superheat the steam flowing inside the suction line. At a condensation temperature of about 120 ° F. (48.9 ° C.) and a pressure of 172 lbs / in ² (118,560 N / m 2), the compressor discharges pressurized refrigerant into the discharge line.

XDX System-Low Temperature Operation

The nominal operating temperature of the evaporator is -5 ° F (-20.5 ° C) and the nominal operating temperature of the condenser is 115 ° F (46.1 ° C). The freezer load of the evaporator is about 3000 Btu / hr (21 g cal / s). The multifunction valve measures that the refrigerant flowing into the saturated steam line at about −5 ° F. (−20.5 ° C.) is about 2975 ft / min (907 km / min). A sensing valve maintains about 20 ° F. (11.1 ° C.), which overheats the steam flowing inside the suction line. At a condensation temperature of about 115 ° F. (46.1 ° C.) and a pressure of about 161 lbs / in ² (110.977 N / m 2), pressurized refrigerant is discharged by the compressor to about 2299 ft / min (701 m / min) inside the discharge line. . The XDX system is operated at low temperature operation, as in medium temperature operation, except that the Tyler Chest Freezer has been delayed for four minutes after defrosting to remove heat from the evaporator coil and drain it from the coil.

The XDX steam compression system is operated for about 24 hours at medium temperature operation and during the low temperature operation cycle. The ambient air temperature inside the Tyler Chest Freezer is measured approximately every minute during the 23 hour test cycle. The air temperature is continuously measured during the test cycle and the steam compression system is operated in refrigeration and defrost mode. During the defrost cycle, the refrigeration cycle is operated in defrost mode until the bulb temperature of the sensing function reaches about 50 ° F. (10 ° C.). The temperature measurement results are shown in Table 1.

Prior art system-medium temperature operation by electric defrost

A bypass line extending between the compressor discharge line and the suction line for the defrosting operation is mounted to the Tyler Chest Freezer. A solenoid valve for opening and closing the flow of the high temperature refrigerant in the line is mounted to the bypass line. During the test the electrical heating element is energized instead of the solenoid. A standard expansion valve is installed close to the evaporator inlet and a temperature sensing bulb is attached to the suction line directly near the evaporator outlet. Sensing valves are set to maintain about 6 ° F. (3.33 ° C.), which overheats useful steam inside the suction line. Prior to operation, the system is charged with approximately 48 oz (1.36 kg) of R-12 refrigerant.

The steam compression system of the prior art is operated for a period of about 24 hours in medium temperature operation. The ambient air temperature inside the Tyler Chest Freezer is measured approximately every minute during the 24-hour test cycle. While the steam compression system is operating in the reverse flow defrost mode and refrigeration mode, the air temperature is continuously measured during the test cycle. During the defrost cycle, the refrigeration circuit is operated in the defrost mode until the temperature of the sensing valve reaches about 50 ° F. (10 ° C.). The temperature measurement results are shown in Table I below.

Prior art system-medium temperature operation by air defrost function.

The Tyler Chest Freezer is provided with a receiving device so that a suitable liquid supply is made to the expansion valve, and a liquid line drying device is installed for further refrigerant storage. As in the reverse flow defrost system, the expansion valve and the sensing valve are arranged in the same position. Sensing valves are set to maintain about 8 ° F. (4.4 ° C.), which overheats the steam flowing in the suction line. Prior to operation, the system is filled with about 34 oz (0.966 kg) of R-12 refrigerant.

The steam compression system of the prior art is operated for a period of about 24 and 1/2 hours at intermediate operating temperatures. The ambient air temperature inside the Tyler Chest Freezer is measured approximately every minute during the 24 and 1/2 hour test cycles. While the steam compression system is operating in defrost and refrigeration mode, the air temperature is continuously measured during the test cycle. According to the prior art, four defrost cycles each lasting about 36 to 40 minutes are programmatic. The temperature measurement results are shown in Table I below.

Table I

Refrigeration temperature (℉ / ℃)

XDX ¹⁾ XDX ¹⁾ Prior Art ²⁾ Prior Art ²⁾

Medium Temperature Low Temperature Electric Defrost Electric Defrost

Average 38.7 / 3.7 4.7 / -15.2 39.7 / 4.3 39.6 / 4.2

Standard Deviation 0.8 0.8 4.1 4.5

Dispersion 0.7 0.6 16.9 20.4

Range 7.1 7.1 22.9 26.0

1) One defrost cycle during the 23 hour test cycle

2) Three defrost cycles during the 24 hour test cycle

Referring to the above description, the temperature inside the Chest Freezer with less temperature change than the system of the prior art is maintained at the required value by the XDX steam compression system arranged according to the present invention. Temperature ranges and deviations obtained during the test cycle are smaller than those of prior art systems. As a result, the XDX system is kept at medium temperatures and low temperatures.

During the defrost cycle, the temperature rise of the Chest chiller is monitored to determine the maximum temperature inside the chiller. In order to prevent spoilage of the food stored inside the chiller, the temperature should be as close as possible to the operating refrigeration temperature. The maximum defrosting temperatures for the XDX system and prior art systems are shown in Table II below.

Table II

Maximum Defrost Temperature (℉ / ℃)

XDX of the prior art

Medium temperature electric defrost electric defrost

44.4 / 6.9 55.0 / 12.8 58.4 / 14.7

Example Ⅱ

Tyler Chest coolers are constructed in accordance with the above description and are further mounted to the electric defrost circuits. The low temperature operation test is performed as described above, and the time for returning the refrigeration unit to the refrigerating operation temperature is measured. A separate test is then carried out using an electric defrost circuit to defrost the evaporator. The time required for the XDX system and the electric defrost system to complete the defrost operation and return to the 5 ° F (-15 ° C) operating set point is shown in Table III.

Table III

Time to return to 5 ° F (-15 ° C) refrigeration temperature

Prior art system with XDX electric defrost function

Defrost

Duration (min) 10 36

Recovery time (min) 24 144

Referring to the above description, the forward flow defrost through the multifunction valve reduces the time for the XDX system to completely defrost the evaporator and return to the cold operation temperature.

Thus, according to the present invention, there is provided a vapor compression system that fully provides the above advantages. Although the present invention has been described and illustrated with reference to specific embodiments thereof, the present invention is not limited to the above embodiments. It is understood by those skilled in the art that modifications and variations can be made without departing from the spirit of the invention. For example, non-halogen refrigerants such as ammonia can be used and similar materials can be used. Therefore, according to the present invention all modifications corresponding to the claims and equivalents of the present invention are included.

Claims (77)

In a vapor compression system, A compressor (12), A discharge line 20 coupling the compressor to the condenser 14, A liquid line 22 coupling the condenser to the first inlet 20 of an expansion valve 42, wherein the expansion valve is configured to expand the heat transfer fluid to form an expanded heat transfer fluid, A saturated steam line 28 coupling the outlet of said expansion valve to an evaporator, A suction line 30 connecting the evaporator to the compressor, and A heat source (25) applied to said expanded heat transfer fluid, wherein said heat transfer fluid is converted to saturated steam before said heat source is transferred to said evaporator. 2. The vapor compression system of claim 1 wherein the heat source comprises heat generated by a compressor (12), a condenser (14), or a discharge line (20). 3. The expansion valve (42) according to claim 2 wherein the expansion valve (42) forms part of the multifunction valve (18), wherein the first inlet of the expansion valve is coupled to the first inlet (24) of the multifunction valve and the expansion The outlet of the valve is coupled to the outlet (41) of the multifunctional valve. 4. The multifunction valve (18) of claim 3, wherein the multifunction valve (18) further comprises a first passageway (249) that couples the expansion valve to a common chamber (246), The common chamber is connected to the outlet 248 of the multifunction valve, wherein the heat transfer fluid is firstly expanded in the first passage 249 and secondly expanded in the common chamber 246. Steam compression system. 4. The system of claim 3, further comprising a temperature sensor 32 mounted to the suction line and operatively connected to the multifunction valve, wherein the discharge line 20 connects the compressor to the second inlet 26 of the multifunction valve. Steam compression system, characterized in that. 6. An output manifold (82) according to claim 5, wherein the compressor consists of a plurality of compressors (80), each of which is connected to the suction line by a collection manifold (100) and to an output manifold (82) connected to the discharge line. Steam discharge system, characterized in that each discharged). 6. The multifunction valve of claim 5, wherein the multifunction valve includes a first passage coupled to the first inlet and a second passage coupled to the second inlet and opened and closed by a second valve, wherein the first passage is And an expansion valve located therein and enclosed by the first valve, wherein the first and second passages terminate in the common chamber. 2. The vapor compression system as recited in claim 1, wherein said heat source comprises an active heat source. 2. The vapor compression system of claim 1 wherein the heat transfer fluid portion is in fluid state upon exit from the evaporator. The method according to any one of claims 1 to 9, Multiple evaporators, -Multifunctional valves, A plurality of saturated steam lines, wherein each saturated steam line connects one of the plurality of multifunctional valves to one of the plurality of evaporators, and A plurality of suction lines, each suction line connecting said one of said plurality of evaporators to said compressor In addition, Wherein a heat source is applied to each of the saturated steam lines, wherein each of the plurality of suction lines is attached with a temperature sensor to transmit a signal to a selected one of the plurality of multifunction valves. 2. The expansion valve according to claim 1, wherein the expansion valve forms part of a recovery valve, wherein the recovery valve 19 A first inlet 124 for introducing the heat transfer fluid into a common chamber, and A first outlet 159 for causing said heat transfer fluid to flow out of said common chamber, Wherein said expansion valve is positioned adjacent said first inlet, said expansion valve volume expands said heat transfer fluid into said common chamber and wherein said heat source is applied to said common chamber. 12. The vapor compression system of claim 11 wherein heat transfer fluid in the common chamber is transformed from a low dry liquid vapor mixture to a high dry liquid vapor mixture through heat addition from the heat source. 12. The recovery valve of claim 11, wherein the recovery valve includes a second inlet 127 for introducing a high temperature heat transfer fluid into a second passage adjacent to the common chamber and a second outlet 130 for allowing a high temperature heat transfer fluid to flow out of the passage. Steam compression system further comprises a). The method of claim 13, wherein the recovery valve The third inlet 126 for introducing a high temperature heat transfer fluid into the common chamber, A first gating valve 46 capable of terminating the flow of heat transfer fluid through the common chamber in a closed position, the first gating valve 46 being configured proximate to the first inlet of the common chamber, and And a second gating valve (50) configured to allow a high temperature heat transfer fluid to flow through the common chamber in the open position and configured to be proximate to the third inlet of the common chamber. 15. The vapor compression system according to claim 14, wherein the recovery valve can defrost the evaporator by closing the first gating valve (46) and opening the second gating valve (50). 4. The vapor compression system of claim 3, wherein the multifunction valve is adjacent to the evaporator. 4. The vapor compression system of claim 3 wherein the multifunction valve is located proximate to the condenser and the saturated vapor line has a longer length than the liquid line. The method of claim 1 wherein the expansion valve A common chamber for expansion of the heat transfer fluid In addition, The common chamber then has a first portion adjacent to a second portion, wherein the first portion comprises a first inlet 244 and an outlet 248, and the second portion includes a back wall opposite the outlet. The outlet discharges a heat transfer fluid from the common chamber, And said expansion valve generates a heat transfer fluid in which a large amount of liquid is separated and spaced from the large amount of steam. 19. The vapor compression system of claim 18, wherein the length of the first portion is 75% of the length of the common chamber (246). In a method of operating a vapor compression system, the method Compressing the heat transfer fluid in the compressor 12 to form a compressed heat transfer fluid, The compressed heat transfer fluid flows through the discharge line 20 to the condenser 14, Condensing the compressed heat transfer fluid in the condenser to form a condensed heat transfer fluid, The condensed heat transfer fluid flows from the condenser through the liquid line 22 to the inlet of the expansion valve 42, Receiving the heat transfer fluid in a liquid state at the inlet of the expansion valve, Converting the condensed heat transfer fluid to a low pressure state at the expansion valve to form an expanded heat transfer fluid, wherein the condensed heat transfer fluid is volume expanded at the expansion valve, The expanded heat transfer fluid flows through the saturated vapor line 28 from the outlet of the expansion valve to the inlet of the evaporator 16, Applying a heat source 25 to said expanded heat transfer fluid, Receive the heat transfer fluid in saturated vapor at the inlet of the evaporator, wherein the flow rate of the heat transfer fluid expanded within the saturated vapor line and the heat source applied to the expanded heat transfer fluid evaporate a portion of the heat transfer fluid Thus forming a saturated vapor before the heat transfer fluid enters the evaporator, where the saturated vapor fills the evaporator, and Returning the saturated steam to the compressor via a suction line (30). 21. The vapor of claim 20 wherein at least about 5% of the heat transfer fluid is evaporated before the heat transfer fluid enters the evaporator, and wherein at the exit of the evaporator a portion of the heat transfer fluid is in a liquid state. How a compression system works. The method of claim 20 wherein the expansion valve forms part of a multifunction valve 18 and the method of operating the vapor compression system is Flowing the compressed heat transfer fluid from the compressor to the second inlet 26 of the multifunction valve via a discharge line, Delivering the compressed heat transfer fluid from the second inlet of the multifunction valve to the outlet 41 of the multifunction valve, and -Flowing said compressed heat transfer fluid from the outlet of said multifunction valve to said evaporator, At this time, the multi-function valve A first inlet 24 for receiving the heat transfer fluid in a liquid state, A second inlet 26 for receiving the heat transfer fluid in a gaseous state, A first passage coupling the first inlet to a common chamber, wherein the first passage includes the expansion valve therein and is opened and closed by a first valve, A second passage that couples the second inlet to the common chamber, wherein the second passage comprises the second passage 48 opened and closed by a second valve, And the common chamber is connected to the outlet (41) of the multifunction valve. 23. The method of claim 22 wherein the method of operating the vapor compression system is Open the second valve of the multifunction valve and stop the flow of heat transfer fluid in the first passage and to initiate flow of the heat transfer fluid through the second passage from the compressor to the common chamber. Defrosting the evaporator by closing a valve. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

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