Heat and mass exchanger liquid line subcooler

Abstract

An air conditioning system for circulating a refrigerant includes a condenser having a vapor inlet for condensing the refrigerant into a high-pressure liquid having a first predetermined temperature. A heat exchanger including an exhaust channel directs air therethrough. The heat exchanger further includes a refrigerant inlet in fluid communication with a refrigerant outlet for receiving a high-pressure liquid and for delivering the high-pressure liquid therethrough. Furthermore, a heat mass exchanger outputs wet working air having a second predetermined temperature. The heat exchanger is in fluid communication with the heat mass exchanger for receiving the working air having a temperature less than the high-pressure liquid. The working air flows through the exhaust channel and over the high-pressure liquid to transfer heat from the high-pressure liquid to the working air for reducing the temperature of the high-pressure liquid.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The subject of the invention relates generally to the conditioning of air, and more specifically, to improving the heat transfer efficiency of an air conditioning system.

2. Description of the Prior Art

Traditional air conditioning systems utilize the vapor-compression refrigeration cycle to condition ambient air into cool air for cooling a surrounding area. The traditional air conditioning system operating in the vapor-compression refrigeration cycle typically includes a compressor, a condenser, a heat exchanger, and an evaporator for transforming the refrigerant from a low pressure heated vapor into a cool mixed liquid-vapor. As air flows over the mixed liquid-vapor, heat from the air is transferred to the mixed liquid-vapor refrigerant to produce cool conditioned air that may be utilized to cool the surrounding area. The heat transferred to the refrigerant vaporizes the remaining liquid in the mixed-liquid vapor resulting in a low pressure heated vapor. This low pressure heated vapor is returned to the compressor to complete the refrigeration cycle. A thermal expansion valve may also be disposed downstream for decreasing the pressure of the refrigerant prior to delivery into the evaporator. By decreasing the pressure of the refrigerant, the remaining liquid can be vaporized more easily.

The thermodynamic characteristics of a typical refrigerant are illustrated by the pressure-enthalpy diagram shown if FIG. 1. The P-h plane is useful in showing the amounts of energy transfer as heat. Referring to FIG. 1, saturated vapor at low pressure enters the compressor and undergoes a reversible adiabatic compression in process 1-2, i.e. a compression which results in no gain or loss of heat. Heat is then rejected at constant pressure in process 2-3. An adiabatic pressure change occurs through the expansion device in process 3-4. The working fluid is then evaporated at constant pressure in process 4-1 to complete the refrigeration cycle.

Today, energy used to generate cool conditioned air has become increasingly important. Air conditioning systems are seen as large consumers of power. Therefore, energy efficient air conditioning has become an important area of investigation. Some current investigations have focused on liquid line cooling using the suction line cooling capacity; however, these systems do not reduce energy input. Instead, they merely increase cooling capacity.

SUMMARY OF THE INVENTION AND ADVANTAGES

In addition to the structure described above, the invention provides for the heat exchanger in fluid communication with the heat mass exchanger for receiving wet working air having a temperature less than the temperature of the high-pressure liquid from the condenser. The working air generated by a heat mass exchanger is flowed through the heat exchanger and over the high-pressure liquid to transfer heat from the high-pressure liquid to the working air for reducing the temperature of the high-pressure liquid.

Accordingly, the evaporative capacity of the evaporator is increased and the overall heat transfer efficiency of the air conditioning system is improved. Additionally, the system leverages the wet working air instead of simply exhausting the working air into the atmosphere to further promote an efficient air conditioning system.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a pressure enthalpy diagram representing the refrigeration process;

FIG. 2 is a hardware schematic of the air conditioning system according the present invention;

FIG. 3 is an isometric view of a heat mass exchanger according to the present invention; and

FIG. 4 is an isometric view of a heat exchanger disposed against the heat mass exchanger according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 2-4, wherein like numerals indicate corresponding parts throughout the several views, an air conditioning system 20 for circulating a refrigerant to thermally condition ambient air introduced into the air conditioning system 20 is generally shown. FIG. 2 shows the air conditioning system 20 including a compressor 22, a condenser 24, a heat exchanger 26, a valve 28, and an evaporator 30 for completing the thermal vapor compression refrigeration cycle that transforms the refrigerant from a low pressure heated vapor into a cool mixed liquid-vapor.

The refrigeration cycle beings at the compressor 22 generally indicated. The compressor 22 includes a low-pressure inlet 32 and a high-pressure outlet 34. The compressor 22 receives the refrigerant in a low-pressure heated vapor state and compresses the refrigerant into a high-pressure superheated vapor where it is output from the high-pressure outlet 34.

The condenser 24 generally indicated has a vapor inlet 36 for receiving the refrigerant in a high-pressure heated vapor state and a liquid outlet 38. As the high-pressure heated vapor enters the vapor inlet 36 and flows to the liquid outlet 38, the high-pressure superheated vapor is condensed into a high-pressure liquid having a first predetermined temperature.

The heat exchanger 26 generally indicated has an exhaust air inlet 40 for receiving air and an exhaust air outlet 42. An exhaust channel 44 extends from the exhaust air inlet 40 to the exhaust air outlet 42 for directing the air therethrough. The heat exchanger 26 also has a refrigerant inlet 46 for receiving the high-pressure liquid and a refrigerant outlet 48. The heat exchanger 26 further includes a refrigerant tube 50 having a cross-section defining flat sides and rounded ends. The refrigerant tube 50 extends into the exhaust channel 44 from the refrigerant inlet 46 to the refrigerant outlet 48 through a plurality of U-shapes to form a serpentine pattern for delivering the high-pressure liquid from the refrigerant inlet 46 to the refrigerant outlet 48.

A valve 28, such as a thermal expansion valve 28, is generally indicated and is disposed between the heat exchanger 26 and the evaporator 30. The thermal expansion valve 28 includes a valve inlet 52 having an inlet diameter d_INLET and a valve outlet 54 having an outlet diameter d_OUTLET greater than the inlet diameter d_INLET. The valve inlet 52 is in fluid communication with the condenser 24 for receiving the high-pressure liquid. As the high-pressure liquid flows from the valve inlet 52 to the valve outlet 54, the pressure of the high-pressure liquid is decreased and the refrigerant transforms from a high-pressure liquid into a cool low-pressure mixed liquid-vapor. By decreasing the pressure of the refrigerant prior to delivery into the evaporator 30, vaporization of the remaining liquid is improved. It is also appreciated that although a thermal expansion valve 28 is described, another thermal expansion device and/or valve 28 that decreases the pressure and/or temperature of the refrigerant may used.

The refrigerant cycle ends at the evaporator 30 generally indicated. The evaporator 30 includes a liquid-vapor inlet 56 for receiving the mixed liquid-vapor and a low-pressure outlet 58 for outputting low-pressure heated vapor. A refrigerant channel 60 is included and extends between the liquid-vapor inlet 56 and the low-pressure outlet 58 for delivering the mixed liquid-vapor therethrough. The evaporator 30 includes a product air inlet 62 for receiving air and a conditioned air outlet 64. An air pathway 66 extends perpendicular to the refrigerant channel 60 from the product air inlet 62 to the conditioned air outlet 64 for conveying air over the mixed liquid-vapor. As air flows over the mixed liquid-vapor, heat is transferred from the air to the refrigerant. In response, liquid from the mixed liquid-vapor refrigerant evaporates and the refrigerant is transformed into a high-pressure heated vapor, which is returned to the condenser 24 to complete the refrigeration cycle. Additionally, by transferring heat from the air flowing over the refrigerant, the cool conditioned air is generated. Furthermore, condensate is generated in response to air flowing over the mixed liquid-vapor. The evaporator 30 may include a drain 68 disposed at the bottom 70 of the evaporator 30 for draining the condensate from the evaporator 30.

A plurality of conduits 72, 74, 76, 78, 80 are used to connect the compressor 22, the condenser 24, the heat exchanger 26, the valve 28, and the evaporator 30 to one another in order to complete the air conditioning system 20. Although conduits 72, 74, 76, 78, 80 are described to connect the air conditioning system 20, any means for providing fluid communication between each of the compressor 22, the condenser 24, the heat exchanger 26 and the valve 28 may be used. Specifically, a first conduit 72 is included having one end connected to the high-pressure outlet 34 of the compressor 22. The opposite end is connected to the vapor inlet 36 of the condenser 24 for delivering the high-pressure superheated vapor from the compressor 22 to the condenser 24. A second conduit 74 is included having one end connected to the liquid outlet 38 of the condenser 24. The opposite end is connected to the refrigerant inlet 46 of the heat exchanger 26 for delivering the high-pressure liquid from the condenser 24 to the heat exchanger 26. A third conduit 76 is included having one end connected to the refrigerant outlet 48 of the heat exchanger 26. The opposite end is connected to the valve inlet 52 of the valve 28 for delivering the high-pressure liquid from the heat exchanger 26 to the valve 28. A fourth conduit 78 is included having one end connected to the valve outlet 54. The opposite end is connected to the liquid-vapor inlet 56 of the evaporator 30 for delivering the mixed liquid-vapor from the valve 28 to the evaporator 30. Lastly, a fifth conduit 80 is included having one end connected to the low-pressure outlet 58 of the evaporator 30. The opposite end is connected to the low-pressure inlet 32 of the compressor 22 for returning the refrigerant being in the low-pressure heated vapor state to the compressor 22.

Traditionally, the air conditioning system 20 thermally conditions ambient air to generate cool conditioned air utilized to cool the surrounding area. However, it is generally understood that the temperature of the air introduced into the evaporator 30 plays an important role in the overall efficiency of the air conditioning system 20. By reducing the temperature of the air prior to input into the evaporator 30, the overall load on the evaporator 30 may be reduced. Accordingly, a heat mass exchanger 82 may be used to provide the air conditioning system 20 with pre-cooled product air. By providing pre-cooled air to the air conditioning system 20, the temperature of the conditioned air generated by the evaporator 30 is further decreased.

Referring to FIG. 3, the heat mass exchanger 82 is generally shown having a plurality of ambient air inlets 84 for receiving ambient air and a plurality of working air outlets 86 for exhausting cooled wet working air. The heat mass exchanger 82 includes a plurality of spaced and parallel walls 88 closed by a top 90 and a base 91 to define air channels 92 generally indicated for directing airflow therein. The air channels 92 further include alternating dry channels 94 extending from one of the ambient air inlets 84 and being closed at the rear ends for flowing dry air therethrough.

The air channels 92 also include wet channels 96 disposed between the dry channels 94 and being closed at the front ends. The wet channels 96 extend to one of the working air outlets 86 for flowing wet air therethrough. A first plurality of the dry channels 94 have a plurality of apertures 98 in the walls 88 for conveying air out of the respective dry channel 94 and into at least one adjacent wet channel 96 to cool the air in the adjacent dry channels 94. A second plurality of the dry channels 94 are included alternating with the first plurality of dry channels 94. The second plurality of dry channels 94 are disposed between two of the wet channels 96 and have a plurality of product air outlets 100 in the tops 90 thereof for directing pre-cooled product air from the second plurality of alternating dry channels 94. Each of the wet channels 96 are lined with a wicking material 102 for retaining a liquid.

The liquid is evaporated in response to airflow conveyed by the apertures 98 in the walls 88 of the dry channels 94 for extracting heat from the adjacent dry channels 94, thereby generating the dry air in the adjacent dry channels 94. The product air inlet 62 of the evaporator 30 is in fluid communication with the product air outlets 100 of the heat mass exchanger 82 for receiving the pre-cooled product air and flowing the pre-cooled air over the mixed liquid-vapor to generate the conditioned air from the conditioned air outlet 64.

The heat mass exchanger 82 may further include a reservoir 104 in fluid communication with the drain 68 of the evaporator 30 for collecting the condensate. The reservoir 104 supplies the condensate to the wicking material 102 of each of the wet air channels to wet the wicking material 102. Although one embodiment of a heat mass exchanger 82 is described above, any device for cooling air while generating wet working air as a by-product of the heat exchanging process may be used.

Traditionally, the wet working air generated by the heat mass exchanger 82 was viewed as being too humid to be utilized and was simply exhausted into the atmosphere. However, the air conditioning system 20 is distinguished by providing a means of flowing the wet working air exhausted from the heat mass exchanger 82 over the refrigerant flowing through the heat exchanger 26. The wet working air exhausted from the heat exchanger 26 has a temperature less than the high-pressure liquid from condenser 24, which flows through the heat exchanger 26. To maximize the air flow delivered to the high-pressure liquid flowing through the heat exchanger 26, the exhaust air inlet 40 of the heat exchanger 26 is disposed against the heat mass exchanger 82 and in fluid communication with the working air outlets 86, as shown in FIG. 4.

Accordingly, the heat exchanger 26 receives the wet working air having a temperature less than the high-pressure liquid from the condenser 24. The wet working air flows through the exhaust channel 44 and over the high-pressure liquid to transfer heat from the high-pressure liquid to the working air for reducing the temperature of the high-pressure liquid. Therefore, the evaporative capacity of the evaporator 30 is increased and the overall efficiency of the air conditioning system 20 is improved. Additionally, the system leverages the wet working air generated by the heat mass exchanger 82 instead of simply exhausting the working air into the atmosphere, thereby further promoting an efficient air conditioning system 20.

While the invention has been described with reference to an exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. An air conditioning system for circulating a refrigerant to thermally condition ambient air introduced into the air conditioning system comprising;

a condenser including a liquid outlet and a vapor inlet for receiving the refrigerant to condense the refrigerant into a high-pressure liquid having a first predetermined temperature,

a heat exchanger having an exhaust air inlet and an exhaust air outlet and an exhaust channel extending from said exhaust air inlet to said exhaust air outlet for directing air therethrough,

said heat exchanger having a refrigerant inlet in fluid communication with a refrigerant outlet for receiving the high-pressure liquid and for delivering the high-pressure liquid therethrough,

a heat mass exchanger having a plurality ambient air inlets for receiving ambient air and a plurality of working air outlets for outputting wet working air having a second predetermined temperature and a plurality of air channels for conveying air from said ambient air inlets to said working air outlets,

said heat exchanger in fluid communication with said heat mass exchanger for receiving the working air having a temperature less than the high-pressure liquid from said condenser and flowing the working air through said exhaust channel and over the high-pressure liquid to transfer heat from the high-pressure liquid to the working air for reducing the temperature of the high-pressure liquid.

2. An air conditioning system as set forth in claim 1 wherein said exhaust air inlet of said heat exchanger is disposed against said heat mass exchanger and in fluid communication with said working air outlets.

3. An air conditioning system as set forth in claim 1 wherein said heat mass exchanger includes walls having apertures and being spaced and parallel from each other and extending from said ambient air inlets to said working air outlets and being enclosed by a top and a base to define said plurality of air channels for splitting said ambient air into said wet working air.

4. An air conditioning system as set forth in claim 3 wherein said air channels include alternating dry channels extending from one of said ambient air inlets and being closed at the rear ends for flowing dry air therethrough and including wet channels disposed between said dry channels and being closed at the front ends and extending to one of said working air outlets for flowing wet air therethrough.

5. An air conditioning system as set forth in claim 4 further comprising a first plurality of said dry channels having said apertures in said walls thereof for conveying air out of a corresponding said dry channel and into at least one adjacent wet channel to cool the air in said adjacent dry channel.

6. An air conditioning system as set forth in claim 5 further comprising a second plurality of said dry channels alternating with said first plurality of dry channels and disposed between two of said wet channels and having a plurality of product air outlets in said tops thereof for conveying pre-cooled product air from said second plurality of alternating dry channels.

7. An air conditioning system as set forth in claim 6 further comprising a wicking material lining each of said wet channels for retaining a liquid to be evaporated in response to airflow conveyed by said apertures in said walls of said dry channels for extracting heat from said adjacent dry channels to generate the dry air in said adjacent dry channels.

8. An air conditioning system as set forth in claim 7 further comprising a reservoir for collecting liquid and for supplying liquid to said wicking material of each of said wet air channels to wet said wicking material.

9. An air conditioning system as set forth in claim 1 further comprising a compressor including a high pressure outlet in fluid communication with said liquid-vapor inlet of said condenser and a low pressure inlet for receiving the refrigerant being in a low-pressure heated vapor state and for compressing the refrigerant from a low-pressure heated vapor into a high-pressure superheated vapor.

10. An air conditioning system as set forth in claim 9 further comprising a valve including a valve inlet having an inlet diameter and being in fluid communication with said refrigerant outlet of said heat exchanger for receiving the high-pressure liquid and including a valve outlet having an outlet diameter greater than said inlet diameter for decreasing the pressure of the high-pressure liquid to transform the refrigerant from the high-pressure liquid into a cool low-pressure mixed liquid-vapor in response to the high-pressure liquid flowing from said valve inlet to said valve outlet.

11. An air conditioning system as set forth in claim 10 further comprising an evaporator including a liquid-vapor inlet for receiving the mixed liquid-vapor and a low-pressure outlet for outputting the low-pressure heated vapor and including a refrigerant channel extending between said liquid-vapor inlet and said low-pressure outlet for delivering the mixed liquid-vapor therethrough.

12. An air conditioning system as set forth in claim 11 wherein said evaporator includes a conditioned air outlet and a product air inlet in fluid communication with said product air outlets of said heat mass exchanger for receiving the pre-cooled product air from said heat mass exchanger air having a temperature greater than the temperature of the mixed liquid-vapor.

13. An air conditioning system as set forth in claim 12 including an air pathway extending perpendicular to said refrigerant channel from said product air inlet to said conditioned air outlet for flowing the pre-cooled air over the mixed liquid-vapor for transferring heat from the pre-cooled air to the mixed liquid-vapor to generate cool conditioned air having a temperature less than the temperature of the pre-cooled air thereby generating condensate in response to the pre-cooled air flowing over the mixed liquid-vapor.

14. An air conditioning system as set forth in claim 12 wherein said evaporator includes a drain disposed at the bottom of said evaporator and being fluid communication with said heat mass exchanger for draining the condensate from said evaporator to said heat mass exchanger for supplying the condensate to said wicking material of each of said wet air channels.

15. An air conditioning system as set forth in claim 9 further comprising a first conduit having one end connected to said high-pressure outlet of said compressor and an opposite end connected to said vapor inlet of said condenser for delivering the refrigerant being in a high-pressure superheated vapor state from said compressor to said condenser.

16. An air conditioning system as set forth in claim 1 further comprising a second conduit having one end connected to said liquid outlet of said condenser and an opposite end connected to said refrigerant inlet of said heat exchanger for delivering the high-pressure liquid from said condenser to said heat exchanger.

17. An air conditioning system as set forth in claim 10 further comprising a third conduit having one end connected to said refrigerant outlet of said heat exchanger and an opposite end connected to said valve inlet for delivering the high-pressure liquid from said heat exchanger to said valve.

18. An air conditioning system as set forth in claim 11 further comprising a fourth conduit having one end connected to said valve outlet and an opposite end connected to said liquid-vapor inlet of said evaporator for delivering the mixed liquid-vapor from said valve to said evaporator.

19. An air conditioning system as set forth in claim 11 further comprising a fifth conduit having one end connected to said low pressure outlet of said evaporator and having an opposite end connected to said low-pressure inlet of said compressor for returning the low-pressure vapor to said compressor.