ROLL BOND HEAT EXCHANGER FOR A HEATING, VENTILATION AND AIR CONDITIONING (HVAC) SYSTEM

FIELD OF TECHNOLOGY

[1] Embodiments of the disclosure generally relate to the field of Heating, Ventilation and Air Conditioning (HVAC), and more particularly to a heat exchanger for a HVAC system.

BACKGROUND

[2] Heating, ventilation and air conditioning (HVAC) systems typically re circulate air in an enclosure such as a room, exhaust a portion of the re circulating air, and simultaneously replace such exhaust air with fresh air. In order to maintain an air temperature and humidity level within a certain space at or near a set point, it is desirable to condition the re circulated and fresh air to the temperature and humidity level set point. Unfortunately, the temperature and humidity of re-circulated and fresh air often differ substantially from those of the set points.

[3] HVAC systems are typically designed according to the worst climatic conditions for a geographic area in which the HVAC system will be located. Such worst case climatic conditions are referred to as a cooling and heating "design day." Conditioning the re-circulated and fresh air during such extreme climatic conditions creates a significant load on the HVAC system. System designers, therefore, typically design the HVAC system with sufficient capacity to maintain the set point during the design day conditions.

[4] Typically, system designers incorporate fin type heat exchangers to achieve desired heat transfer rates and to maintain the set point during design day conditions. A fin type heat exchanger includes multiple fins added on the multiple copper tubes that carry refrigerant. Further, ends of the copper tubes are brazed row by row. However, the fin type heat exchangers may make the HVAC system oversized as the fin type heat exchanger is very stiff and difficult to be shaped to optimize the size requirement. Also, such type of heat exchangers creates a lot of structural noise due to variation in part assembly. Moreover, in order to compensate for the load variations and flow induced noises, additional component such as accumulator or receiver are required to be employed external to the fin type heat exchanger.

SUMMARY

[5] A roll bond heat exchanger for a Heating, Ventilation and Air Conditioning (HVAC) system is disclosed. According to one aspect of the present invention, an apparatus includes at least one roll bonded sheet formed using at least two sheets by a roll welding method. The at least one roll bonded sheet includes a first hollow section, having an inlet and an outlet, for providing a flow passage for first fluid. The at least one roll bonded sheet also includes openings for providing a flow passage for a second fluid such that the openings allows the second fluid to pass along the surface of the at least one roll bonded sheet and cross across the openings of the at least one roll bonded sheet in such a way that heat is transferred between the first fluid and the second fluid thereby achieving desired thermodynamic state changes in the HVAC system.

[6] The apparatus further includes a second hollow section located in the flow passage of the first fluid and prior to the outlet of the first hollow section to control fluctuations and flow noise generated due to load variations and unbalanced flow distribution in the HVAC system.

[7] According to another aspect of the present invention, a HVAC system for an enclosure includes a first heat exchanger for absorbing heat from air from a low pressure liquid refrigerant and outputting a low pressure gaseous refrigerant to provide thermal comfort inside the enclosure, and a compressor connected to the first heat exchanger for converting the low pressure gaseous refrigerant into a high pressure gaseous refrigerant. The HVAC system further includes a second heat exchanger connected to the compressor for transferring the heat from the high pressure gaseous refrigerant to atmospheric air, and outputting a high pressure liquid refrigerant to the first heat exchanger.

[8] At least one of the first heat exchanger and the second heat exchanger includes one or more roll bonded sheets, each of the one or more roll bonded sheets having a first hollow section, having an inlet and an outlet, for providing a flow passage for refrigerant. Also, each of the one or more roll bonded sheets includes one or more openings for providing a flow passage for air, wherein the air passes along the surface of the each of the one or more roll bonded sheets and crosses across the one or more openings of the each of the one or more roll bonded sheets to achieve desired thermodynamic state changes. Further, each of the one or more roll bonded sheet includes a second hollow section located in the flow passage of the refrigerant and prior to the outlet of the first hollow section to control fluctuations and flow noise generated due to load variations and unbalanced flow distribution in the HVAC system.

[9] Other features of the embodiments will be apparent from the accompanying drawings and from the detailed description that follows.

BRIEF DESCRIPTION OF THE VIEW OF THE DRAWINGS

[10] Figure 1 illustrates a cross-sectional view of a roll bond heat exchanger for use in a HVAC system, according to one embodiment.

[11] Figure 2A illustrates a cross-sectional view of an accumulator/receiver in the roll bond, according to one embodiment.

[12] Figure 2B illustrates a cross-sectional view of hollow sections in the roll bond, according to one embodiment.

[13] Figures 3A-3D illustrate cross-sectional views of the roll bond heat exchanger such as those shown in Figure 1, according one embodiment.

[14] Figure 4 illustrates a cross-sectional view of an opening with a burr, according to one embodiment.

[15] Figure 5 illustrates a schematic view of an exemplary evaporator of an air conditioner, according to one embodiment.

[16] Figure 6 illustrates a schematic view of an exemplary condenser of an air conditioner, according to one embodiment.

[17] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

[18] A roll bond heat exchanger for a Heating, Ventilation and Air Conditioning (HVAC) system is disclosed. The following description is merely exemplary in nature and is not intended to .limit the present disclosure, applications, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

[19] The terms "roll bond" and roll bonded sheet" are used interchangeably throughout the document.

[20] .Figure 1 illustrates a cross-sectional view of a roll bond heat exchanger 100 for use in a HVAC system, according to one embodiment. In Figure 1, the roll bond heat exchanger 100 includes a roll bond 102 formed using two sheets roll bonded using a roll welding method. The sheets can be of aluminum or its alloys having desired thickness. The roll bond heat exchanger 100 includes a first hollow section 104, second hollow sections 106A-E, and openings 108.

[21] The first hollow section 104 provides a flow passage for the first fluid (hereafter referred to as refrigerant). It can be noted that, the flow passage for the refrigerant can be in series, parallel or in combination of both. As can be seen from Figure 1, the refrigerant enters at an inlet 110 of the first hollow section 104 and exits at an outlet 112 of the first hollow section 104. The second hollow sections 106A-E are provided in the flow passage of the refrigerant and prior to the outlet 112. The second hollow sections 106A-E may act as an accumulator/receiver and/or a tuned resonator.

[22] The second hollow sections 106A-E are provided to control fluctuations and flow noise generated due to load variations and unbalanced flow distribution in the HVAC system. Also, the second hollow sections 106A-E are provided for attenuating structural noise and vibrations at tuned frequencies. The first hollow section 104 and the second hollow sections 106A-E are formed by inflating the roll bond 102 by applying fluid pressure.

[23] The openings 108 in the roll bond 102 provide a flow passage for a second fluid (herein after referred to as air). The openings 108 are of different shapes and sizes and are positioned at different locations on the roll bond 102 such that the air passes along the surface of the roll bond 102 and crosses across the openings 108. This helps efficient heat transfer between refrigerant flowing through the first hollow section 104 and the air. In some embodiments, extruded portions such as burrs are retained during manufacturing of the roll bond 102 to increase heat transfer area and to provide appropriate flow of air. The roll bond heat exchanger 100 also includes a source such as a fan or a blower for generating required flow of air passing though the openings 108.

[24] in an exemplary implementation, the above roll bond exchanger 100 can be implemented in an HVAC system (e.g., air-conditioner, heater, and the like). For example, the roll bond heat exchanger 100 can be used as an evaporator (as shown in Figure 5) and/or as a condenser (as shown in Figure 6) along with a compressor of the air-conditioner (e.g., which compresses low pressure gaseous refrigerant to high pressure gaseous refrigerant). It can be noted that, the air-conditioner may not require additional components such as an accumulator or a receiver as these components are incorporated inside the roll bond heat exchanger 100 along the flow passage of the refrigerant.

[25] Figure 2A illustrates a cross-sectional view of an accumulator/receiver 202 in the roll bond 102, according to one embodiment. The accumulator/receiver 202 is incorporated within the roll bond heat exchanger 100. The accumulator/receiver 202 has an inlet 204 for receiving the refrigerant and an outlet 206 for providing the stabilized refrigerant.

[26] Figure 2B illustrates a cross-sectional view of hollow sections 250A-C in the roll bond 102, according to one embodiment. The hollow sections 250A-C includes accumulators/receivers 250A-B and a tuned resonator 250C. It is appreciated that, the accumulators/receivers 250A-B and the tuned resonator 250C are exemplary embodiments of the second hollow sections 106A-E of Figure 1. The accumulators/receivers 250A-B and the tuned resonator 250C have an inlet 252 for receiving the refrigerant and an outlet 254 for providing the stabilized refrigerant. Exemplary tuned resonator 250C may include Helmets resonator. The tuned resonator 250C attenuates structural flow noise and vibrations at tuned frequencies. One can envision that, more than one tuned resonators can be incorporated in the roll bond 102 based on the application requirement.

[27] Figures 3A-3D illustrate cross-sectional views 300A-D of the roll bond heat exchanger 100 such as those shown in Figure 1, according one embodiment. It can be seen from Figure 3 that first hollow sections 302A-D is semicircular, oval, trapezoidal, hexagonal in shape, respectively. Also, cross- sectional view 300A-D illustrates openings 304-306 in the roll bond heat exchanger 100.

[28] Figure 4 illustrates a cross-sectional view of an opening 400 with a burr 402, according to one embodiment. It is appreciated that, the opening 400 is an exemplary embodiment of the openings 108. The opening 400 in the roll bond 102 is formed using an extrusion process such as punching. The extrusion
process may leave some burrs (e.g., burr 402) which are retained and assembled in defined direction while manufacturing the roll bond to increase heat transfer area.

[29] Figure 5 illustrates a schematic view of an exemplary evaporator 500 of an air conditioner, according to one embodiment. It is appreciated that, the evaporator 500 is an exemplary embodiment of the roll bond heat exchanger 100 of Figure 1. As shown in Figure 5, the evaporator 500 includes multiple roll bonds 502A-N. The multiple roll bonds 502A-N are bonded via clamps or spacers 516. Also, insulating pads such as polyurethane foam are used between the roll bonds 502A-N to prevent air from leaking from the gaps between the roll bonds 502A-N.

[30] As illustrated, an inlet header 508 is connected to an inlet 504 of a first hollow section of each of the multiple roll bonds 502A-N. The inlet header 508 enables distribution of refrigerant to the first hollow section. Similarly, an outlet header 512 is connected to an outlet 510 of the first hollow section for collecting and discharging the refrigerant outputted by the first hollow section.

[31] In some embodiments, one or more openings 514 of each of the multiple roll bonds are axially offset with respect to one or more openings of adjacent roll bond by a distance X. This arrangement helps achieve desired flow rate of air and improve heat transfer. Each of the multiple roll bonds 502A-N includes an accumulator (not shown) for control load fluctuations and flow noises.
[32] In an exemplary operation, low pressure liquid refrigerant (e.g., having an operating pressure of 6-30MRA) is received by the inlet 504 of each of the roll bonds 502A-N via the inlet header 508. The low pressure liquid refrigerant passes through the first hollow section and exits the first hollow section via the outlet 510 to the outlet header 512 as low pressure gaseous refrigerant. When the low pressure liquid refrigerant passes through the first hollow section, the blower draws in air such that the air passes along the surface of each of the roll bonds 502A-N, and crosses across the one or more openings 514, thereby absorbing heat from the low pressure liquid refrigerant leading to thermodynamic state changes in refrigerant. Although, the evaporator 500 of Figure 5 is described having multiple roll bonds, one can envision that the evaporator 500 may include a single roll bond.
[33] Figure 6 illustrates a schematic view of an exemplary condenser 600 of an air conditioner, according to one embodiment. The condenser 600 is similar to the evaporator 500 of Figure 5, hence the explanation thereof is omitted. In the condenser 600, a fan blows air over the roll bonds 602A-N to absorb heat from the high pressure gaseous refrigerant and outputs high pressure liquid refrigerant to a capillary device or expansion device. The capillary or expansion device converts the high pressure liquid refrigerant into low pressure gaseous refrigerant which is provided at the inlet of the evaporator 500 of Figure 5.
[34] In various embodiments, the roll bond heat exchanger described in Figures 1-6 is flexible and can be bent to any shape as required by design of HVAC system. The roll bond heat exchanger 100 provides desired cross-section of tube, and bonding strength. The roll bond heat exchanger is also capable of withstanding high temperature and pressure along with achieving higher heat transfer rate requirement in the HVAC system. Moreover, the roll bond heat exchanger eliminates noises and fluctuation due to load variations through receiver/accumulator and tuned resonator.
[35] It will be appreciated that the various embodiments discussed herein may not be the same embodiment, and may be grouped into various other embodiments not explicitly disclosed herein. In addition, it will be appreciated that the various operations, processes, and methods disclosed herein may be embodied in a machine-readable medium and/or a machine accessible medium compatible with a data processing system (e.g., a computer system), and may be performed in any order (e.g., including using means for achieving the various operations). Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.

CLAIMS

What is claimed is:

1. An apparatus for a Heat Ventilation and Air Conditioning (HVAC) system comprising:

at least one roll bonded sheet formed using at least two sheets by a roll welding method, characterized in that is:

a first hollow section, having an inlet and an outlet, for providing a flow passage for a first fluid; and

one or more openings for providing a flow passage for a second fluid, wherein the one or more openings allows the second fluid to pass along the surface of the at least one roll bonded sheet and cross across the one or more openings of the at least roll bonded sheet in such a way that heat is transferred between the first fluid and the second fluid thereby achieving desired thermodynamic state changes in the HVAC system.

2. The apparatus of claim 1, further comprises:

a second hollow section located in the flow passage of the first fluid and prior to the utlet of the first hollow section to control fluctuations and flow noise generated due to load variations and unbalanced flow distribution in the HVAC system.

3. The apparatus of claim 1, further comprises:

a tuned resonators provided in the flow passage of the first fluid for attenuating structural noise and vibrations at tuned frequencies.

4. The apparatus of claim 1, further comprises:

a source for generating a flow of the second fluid that passes along the surface of the at least one roll bonded sheet and crosses across the one or more openings of the at least one roll bonded sheet.

5. The apparatus of claim 1, wherein the one or more openings are of different shapes and sizes and are positioned at different locations on the at least one roll bonded sheet so that second fluid flows perpendicular to the direction of flow of the first fluid.

6. The apparatus of claim 1, wherein the first fluid is refrigerant and the second fluid is air.

7. The apparatus of claim 1, wherein the first fluid is having an operating pressure and flow rate approximately in the range of about 6-30 MPa and 100-300 liters/hr respectively.

8. The apparatus of claim 1, wherein the flow passage of the first fluid in the at least one roll bonded sheet are in parallel, series or in combination.

9. The apparatus of claim 1, wherein the one or more openings in the at least one roll bonded sheet include extruded portions to increase heat transfer area and to provide appropriate flow of the second fluid.

10. An HVAC system for an enclosure comprising:

a first heat exchanger for absorbing heat from air from a low pressure liquid refrigerant and outputting a low pressure gaseous refrigerant to provide thermal comfort inside the enclosure;

a compressor connected to the first heat exchanger for converting the low pressure gaseous refrigerant into a high pressure gaseous refrigerant; and

a second heat exchanger connected to the compressor for transferring the heat from the high pressure gaseous refrigerant to atmospheric air and outputting high pressure liquid refrigerant to the first heat exchanger, characterized in that, at least one of the first heat exchanger and the second heat exchanger comprises:

one or more roll bonded sheets, each of the one or more roll bonded sheets comprises:

a first hollow section, having an inlet and an outlet, for providing a flow passage for refrigerant; and

one or more openings for providing a flow passage for air, wherein the air passes along the surface of the each of the one or more roll bonded sheets and crosses across the one or more openings of the each of the one or more roll bonded sheets to compensate heat exchange with ambient air in the enclosure.

11. The HVAC system of claim 10, wherein each of the one or more roll bonded sheets further comprises:

a second hollow section located in the flow passage of the refrigerant and prior to the outlet of the first hollow section to control fluctuations and flow noise generated due to load variations and unbalanced flow distribution in the HVAC system.

12. The HVAC system of claim 10, wherein each of the one or more roll bonded sheets further comprises:

a tuned resonators provided in the flow passage of the refrigerant for attenuating structural noise and vibrations at tuned frequencies.

13. The HVAC system of claim" 10, wherein at least one of the first heat exchanger and the second heat exchanger further comprises:

an inlet header connected to the inlet for distributing the refrigerant to the first hollow section of each of the one or more roll bonded sheets; and

an outlet header connected to the outlet for collecting and discharging the refrigerant from the first hollow section of each of the one or more roll bonded sheets.

14. The HVAC system of claim 10, wherein at least one of the first heat exchanger and the second heat exchanger further comprises:

a source for generating a flow of the air that passes along the surface of the each of the one or more roll bonded sheets and crosses across the one or more openings of the each of the one or more roll bonded sheets.

15. The HVAC system of claim 10, wherein the one or more openings are of different shapes and sizes and are positioned at different locations on each of the one or more roll bonded sheets so that second fluid flow perpendicular to the direction of flow of the first fluid.

16. The HVAC system of claim 15, wherein the one or more openings of each of the one or more roll bonded sheets are axially offset with respect to one or more openings of an adjacent roll bonded sheet to achieve desired flow rate of the second fluid and heat transfer.

17. The HVAC system of claim 10, wherein the one or more roll bonded sheets are bonded together using clamps or spacers and using insulating pads to prevent leakage of the second fluid.