MICROCHANNEL HEAT EXCHANGER

BACKGROUND

This disclosure relates generally to heating, ventilation, and/or air conditioning (HVAC) systems. Specifically, the present disclosure relates to microchannel heat exchangers for HVAC units.

This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present techniques, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as an admission of any kind.

A heating, ventilation, and/or air conditioning (HVAC) system may be used to thermally regulate an environment, such as a building, house, or other structure. The HVAC system may include a vapor compression system, which includes heat exchangers, such as condensers, which transfer thermal energy between the HVAC system and the environment. A refrigerant may be used as a heat transfer fluid that is directed through the heat exchangers of the vapor compression system. Microchannel heat exchangers often provide improved heat transfer performance over traditional heat exchangers.

SUMMARY

A summary of certain embodiments disclosed herein is set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of these certain embodiments and that these aspects are not intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects that may not be set forth below.

The present disclosure relates to a heat exchanger having a microchannel heat exchanger tube that may flow a refrigerant therethrough. The microchannel heat exchanger tube may extend from a first end of the microchannel heat exchanger tube to a second end of the microchannel heat exchanger tube, and the microchannel heat exchanger tube may have a sinusoidal configuration between the first end and the second end.

The present disclosure also relates to a heat exchanger having a plurality of microchannel heat exchanger tubes. Each microchannel heat exchanger tube may flow refrigerant therethrough and extend from a first end of each microchannel heat exchanger tube to a second end of each microchannel heat exchanger tube. Each microchannel heat exchanger tube may have a tube body and a plurality of microchannels formed in the tube body. Each tube body and each microchannel may have a respective sinusoidal configuration.

The present disclosure also relates to a heat exchanger that has a plurality of microchannel tubes. Each microchannel tube may flow refrigerant therethrough and extend from a first end of each microchannel heat exchanger tube to a second end of each microchannel heat exchanger tube. Each microchannel tube may have a tube body and a plurality of microchannels formed in the tube body. The heat exchanger may also have a plurality of fins. Each fin may be disposed between and couple to adjacent microchannel tubes of the plurality of microchannel tubes. Each tube body, each microchannel, and each fin may have a respective sinusoidal configuration.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of this disclosure may be better understood upon reading the following detailed description and upon reference to the drawings in which:

FIG. 1 is a schematic of an embodiment of an environmental control system for building environmental management that may employ an HVAC unit, in accordance with an aspect of the present disclosure;

FIG. 2 is a perspective view of an embodiment of an HVAC unit that may be used in the environmental control system of FIG. 1, in accordance with an aspect of the present disclosure;

FIG. 3 is a perspective view of an embodiment of a residential heating and cooling system, in accordance with an aspect of the present disclosure;

FIG. 4 is a schematic of an embodiment of the vapor compression system that may be used in any of the systems of FIGS. 1-3, in accordance with an aspect of the present disclosure;

FIG. 5 is a side view of an embodiment of a microchannel heat exchanger that may be used in any of the systems of FIGS. 1-4, in accordance with an aspect of the present disclosure;

FIG. 6 is a perspective view of an embodiment of a configuration of sinusoidal heat exchanger fins coupled to sinusoidal microchannel tubes, in accordance with an aspect of the present disclosure;

FIG. 7A is a perspective view of an embodiment of a sinusoidal microchannel tube that may be used in the microchannel heat exchanger of FIG. 5, in accordance with an aspect of the present disclosure;

FIG. 7B is a side view of the embodiment of the sinusoidal microchannel tube of FIG. 7A, in accordance with an aspect of the present disclosure;

FIG. 8A is a perspective view of an embodiment of a sinusoidal microchannel tube that may be used in the microchannel heat exchanger of FIG. 5, in accordance with an aspect of the present disclosure;

FIG. 8B is a side view of the embodiment of the sinusoidal microchannel tube of FIG. 8A, in accordance with an aspect of the present disclosure;

FIG. 9A is a perspective view of an embodiment of a sinusoidal microchannel tube that may be used in the microchannel heat exchanger of FIG. 5, in accordance with an aspect of the present disclosure;

FIG. 9B is a side view of the embodiment of the sinusoidal microchannel tube of FIG. 9A, in accordance with an aspect of the present disclosure;

FIG. 10A is a perspective view of an embodiment of a sinusoidal microchannel tube that may be used in the microchannel heat exchanger of FIG. 5, in accordance with an aspect of the present disclosure; and

FIG. 10B is a side view of the embodiment of the sinusoidal microchannel tube of FIG. 10A, in accordance with an aspect of the present disclosure.

DETAILED DESCRIPTION

One or more specific embodiments of the present disclosure will be described below. These described embodiments are only examples of the presently disclosed techniques. Additionally, in an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

A heating, ventilation, and/or air conditioning (HVAC) unit is a system that implements a vapor compression cycle, such as a refrigeration cycle, to provide conditioned air to a building or other conditioned space. Specifically, an HVAC unit may include a heat exchanger, such as an evaporator or a condenser, across which an air flow is passed to condition the air flow before the air flow is supplied to the building. The heat exchanger transfers thermal energy between a heat transfer fluid, such as a refrigerant, and a fluid to be conditioned, such as the air flow. In a microchannel heat exchanger, a series of microchannel tubes are physically and thermally connected by heat exchanger fins. Each microchannel tube of the microchannel heat exchanger extends between the ends, or the manifolds, of the microchannel heat exchanger. Additionally, each microchannel tube has at least one microchannel that provides a path for the heat transfer fluid to flow through each microchannel tube of the microchannel heat exchanger. The heat exchanger fins permit an air flow to pass across the microchannel heat exchanger and promote heat transfer with the heat transfer fluid by directing the air flow towards and across the microchannel tubes.

Embodiments of the present disclosure are directed to a microchannel heat exchanger, such as an evaporator or a condenser, having a plurality of sinusoidal microchannel tubes extending from a first manifold of the microchannel heat exchanger to a second manifold of the microchannel heat exchanger. Each microchannel tube may have one or more sinusoidal microchannels extending from a first end of the microchannel tube to a second end of the microchannel tube.

The sinusoidal configuration, or the sinusoidal shape, of the microchannels increases the efficiency of thermal energy transfer between refrigerant or other working fluid flowing through the microchannel tubes and an air flow, as compared to microchannels having a straight shape or a flat shape. Specifically, the sinusoidal shape of the microchannels increases the path length traveled by the refrigerant through the microchannel heat exchanger, thereby increasing the heat transfer area of the microchannel tubes. Additionally, the sinusoidal shape of the microchannels induces turbulence to the flow of the refrigerant through the sinusoidal microchannel tubes, thereby increasing the heat transfer coefficient of the refrigerant. The increase in the heat transfer area and the increase in the heat transfer coefficient of the refrigerant enhances the heat transfer rate between the refrigerant and airflow within the microchannel heat exchanger.

The sinusoidal shape of the microchannel tube also generates additional air resistance to the air flow passing across the heat exchanger as compared to a heat exchanger having tubes with a straight shape or a flat shape. The additional air resistance increases the heat transfer rate between the refrigerant and the air flow flowing across the heat exchanger because the air flow remains in contact with the sinusoidal microchannel tubes for a longer period of time than tubes with a straight shape or a flat shape. Further, the microchannel heat exchanger may have one or more heat exchanger fins disposed between adjacent sinusoidal microchannel tubes. The heat exchanger fin physically and thermally connects the adjacent sinusoidal microchannel tubes and provides air resistance to the air flow passing through the heat exchanger. In certain embodiments, the heat exchanger fins also have a sinusoidal shape. Accordingly, embodiments of the microchannel heat exchanger disclosed herein efficiently remove thermal energy from the refrigerant, and thus improve an efficiency of the HVAC system.

As used herein, the term “sinusoidal,” “sinusoidal shape,” or “sinusoidal configuration” may refer to a sine wave-like shape or curve of a microchannel, a microchannel tube, or a heat exchanger fin along the respective length of the microchannel, the microchannel tube, or the heat exchanger fin between a first manifold and a second manifold of a heat exchanger. That is, the cross-sectional shape of the microchannel, the microchannel tube, or the heat exchanger fin taken along a length of the heat exchanger between the manifolds of the heat exchanger resembles a graphical representation of a sine wave with a desired number of crests, a desired number of troughs, and a desired amplitude. For example, a sinusoidal microchannel tube may resemble a sine wave or sine curve with two crests, two troughs, and an amplitude of two. The amplitude may correspond to a desired distance of each crest and each trough from a center axis of a sinusoidal microchannel, a sinusoidal microchannel tube, or a sinusoidal heat exchanger fin. The desired distance may be measured in micrometers, millimeters, or any other suitable distance unit. For example, an amplitude of two may correspond to the position of each crest and the position of each trough of a sinusoidal microchannel tube being two micrometers from the center axis of a sinusoidal microchannel tube.

In certain embodiments, the sinusoidal shape of a microchannel, a microchannel tube, and/or a heat exchanger fin may be represented by a mathematical sine function, and the number of crests, the number of troughs, and the amplitude may be derived based on the mathematical sine function. In certain embodiments, the sinusoidal shape of the microchannel, the microchannel tube, and/or the heat exchanger fin may resemble at least a portion of a graphical representation of the mathematical sine function. For example, a particular mathematical sine function may be represented by a continuous waveform having an amplitude of two and alternating crests and troughs. The corresponding sinusoidal shape of a microchannel, a microchannel tube, and/or a heat exchanger fin between a first manifold of a heat exchanger and a second manifold of the heat exchanger may resemble a portion of the continuous waveform having two crests and two troughs.

Turning now to the drawings, FIG. 1 illustrates an embodiment of a heating, ventilation, and/or air conditioning (HVAC) system for environmental management that may employ one or more HVAC units. As used herein, an HVAC system includes any number of components configured to enable regulation of parameters related to climate characteristics, such as temperature, humidity, air flow, pressure, air quality, and so forth. For example, an “HVAC system” as used herein is defined as conventionally understood and as further described herein. Components or parts of an “HVAC system” may include, but are not limited to, all, some of, or individual parts such as a heat exchanger, a heater, an air flow control device, such as a fan, a sensor configured to detect a climate characteristic or operating parameter, a filter, a control device configured to regulate operation of an HVAC system component, a component configured to enable regulation of climate characteristics, or a combination thereof. An “HVAC system” is a system configured to provide such functions as heating, cooling, ventilation, dehumidification, pressurization, refrigeration, filtration, or any combination thereof. The embodiments described herein may be utilized in a variety of applications to control climate characteristics, such as residential, commercial, industrial, transportation, or other applications where climate control is desired.

In the illustrated embodiment, a building 10 is air conditioned by a system that includes an HVAC unit 12. The building 10 may be a commercial structure or a residential structure. As shown, the HVAC unit 12 is disposed on the roof of the building 10; however, the HVAC unit 12 may be located in other equipment rooms or areas adjacent the building 10. The HVAC unit 12 may be a single package unit containing other equipment, such as a blower, integrated air handler, and/or auxiliary heating unit. In other embodiments, the HVAC unit 12 may be part of a split HVAC system, such as the system shown in FIG. 3, which includes an outdoor HVAC unit 58 and an indoor HVAC unit 56.

The HVAC unit 12 is an air cooled device that implements a refrigeration cycle to provide conditioned air to the building 10. Specifically, the HVAC unit 12 may include one or more heat exchangers, such as a condenser, across which an air flow is passed to condition the air flow before the air flow is supplied to the building. In the illustrated embodiment, the HVAC unit 12 is a rooftop unit (RTU) that conditions a supply air stream, such as environmental air and/or a return air flow from the building 10. After the HVAC unit 12 conditions the air, the air is supplied to the building 10 via ductwork 14 extending throughout the building 10 from the HVAC unit 12. For example, the ductwork 14 may extend to various individual floors or other sections of the building 10. In certain embodiments, the HVAC unit 12 may be a heat pump that provides both heating and cooling to the building with one refrigeration circuit configured to operate in different modes. In other embodiments, the HVAC unit 12 may include one or more refrigeration circuits for cooling an air stream and a furnace for heating the air stream.

A control device 16, one type of which may be a thermostat, may be used to designate the temperature of the conditioned air. The control device 16 also may be used to control the flow of air through the ductwork 14. For example, the control device 16 may be used to regulate operation of one or more components of the HVAC unit 12 or other components, such as dampers and fans, within the building 10 that may control flow of air through and/or from the ductwork 14. In some embodiments, other devices may be included in the system, such as pressure and/or temperature transducers or switches that sense the temperatures and pressures of the supply air, return air, and so forth. Moreover, the control device 16 may include computer systems that are integrated with or separate from other building control or monitoring systems, and even systems that are remote from the building 10.

FIG. 2 is a perspective view of an embodiment of the HVAC unit 12. In the illustrated embodiment, the HVAC unit 12 is a single package unit that may include one or more independent refrigeration circuits and components that are tested, charged, wired, piped, and ready for installation. The HVAC unit 12 may provide a variety of heating and/or cooling functions, such as cooling only, heating only, cooling with electric heat, cooling with dehumidification, cooling with gas heat, or cooling with a heat pump. As described above, the HVAC unit 12 may directly cool and/or heat an air stream provided to the building 10 to condition a space in the building 10.

As shown in the illustrated embodiment of FIG. 2, a cabinet 24 encloses the HVAC unit 12 and provides structural support and protection to the internal components from environmental and other contaminants. In some embodiments, the cabinet 24 may be constructed of galvanized steel and insulated with aluminum foil faced insulation. Rails 26 may be joined to the bottom perimeter of the cabinet 24 and provide a foundation for the HVAC unit 12. In certain embodiments, the rails 26 may provide access for a forklift and/or overhead rigging to facilitate installation and/or removal of the HVAC unit 12. In some embodiments, the rails 26 may fit into “curbs” on the roof to enable the HVAC unit 12 to provide air to the ductwork 14 from the bottom of the HVAC unit 12 while blocking elements such as rain from leaking into the building 10.

The HVAC unit 12 includes heat exchangers 28 and 30 in fluid communication with one or more refrigeration circuits. Tubes within the heat exchangers 28 and 30 may circulate refrigerant, such as R-410A, through the heat exchangers 28 and 30. The tubes may be of various types, such as multichannel tubes, microchannel tubes, conventional copper or aluminum tubing, and so forth. Together, the heat exchangers 28 and 30 may implement a thermal cycle in which the refrigerant undergoes phase changes and/or temperature changes as it flows through the heat exchangers 28 and 30 to produce heated and/or cooled air. For example, the heat exchanger 28 may function as a condenser where heat is released from the refrigerant to ambient air, and the heat exchanger 30 may function as an evaporator where the refrigerant absorbs heat to cool an air stream. In other embodiments, the HVAC unit 12 may operate in a heat pump mode where the roles of the heat exchangers 28 and 30 may be reversed. That is, the heat exchanger 28 may function as an evaporator and the heat exchanger 30 may function as a condenser. In further embodiments, the HVAC unit 12 may include a furnace for heating the air stream that is supplied to the building 10. While the illustrated embodiment of FIG. 2 shows the HVAC unit 12 having two of the heat exchangers 28 and 30, in other embodiments, the HVAC unit 12 may include one heat exchanger or more than two heat exchangers.

The heat exchanger 30 is located within a compartment 31 that separates the heat exchanger 30 from the heat exchanger 28. Fans 32 draw air from the environment through the heat exchanger 28. Air may be heated and/or cooled as the air flows through the heat exchanger 28 before being released back to the environment surrounding the rooftop unit 12. A blower assembly 34, powered by a motor 36, draws air through the heat exchanger 30 to heat or cool the air. The heated or cooled air may be directed to the building 10 by the ductwork 14, which may be connected to the HVAC unit 12. Before flowing through the heat exchanger 30, the conditioned air flows through one or more filters 38 that may remove particulates and contaminants from the air. In certain embodiments, the filters 38 may be disposed on the air intake side of the heat exchanger 30 to prevent contaminants from contacting the heat exchanger 30.

The HVAC unit 12 also may include other equipment for implementing the thermal cycle. Compressors 42 increase the pressure and temperature of the refrigerant before the refrigerant enters the heat exchanger 28. The compressors 42 may be any suitable type of compressors, such as scroll compressors, rotary compressors, screw compressors, or reciprocating compressors. In some embodiments, the compressors 42 may include a pair of hermetic direct drive compressors arranged in a dual stage configuration 44. However, in other embodiments, any number of the compressors 42 may be provided to achieve various stages of heating and/or cooling. As may be appreciated, additional equipment and devices may be included in the HVAC unit 12, such as a solid-core filter drier, a drain pan, a disconnect switch, an economizer, pressure switches, phase monitors, and humidity sensors, among other things.

The HVAC unit 12 may receive power through a terminal block 46. For example, a high voltage power source may be connected to the terminal block 46 to power the equipment. The operation of the HVAC unit 12 may be governed or regulated by a control board 48. The control board 48 may include control circuitry connected to a thermostat, sensors, and alarms. One or more of these components may be referred to herein separately or collectively as the control device 16. The control circuitry may be configured to control operation of the equipment, provide alarms, and monitor safety switches. Wiring 49 may connect the control board 48 and the terminal block 46 to the equipment of the HVAC unit 12.

FIG. 3 illustrates a residential heating and cooling system 50, also in accordance with present techniques. The residential heating and cooling system 50 may provide heated and cooled air to a residential structure, as well as provide outside air for ventilation and provide improved indoor air quality (IAQ) through devices such as ultraviolet lights and air filters. In the illustrated embodiment, the residential heating and cooling system 50 is a split HVAC system. In general, a residence 52 conditioned by a split HVAC system may include refrigerant conduits 54 that operatively couple the indoor unit 56 to the outdoor unit 58. The indoor unit 56 may be positioned in a utility room, an attic, a basement, and so forth. The outdoor unit 58 is typically situated adjacent to a side of residence 52 and is covered by a shroud to protect the system components and to prevent leaves and other debris or contaminants from entering the unit. The refrigerant conduits 54 transfer refrigerant between the indoor unit 56 and the outdoor unit 58, typically transferring primarily liquid refrigerant in one direction and primarily vaporized refrigerant in an opposite direction.

When the system shown in FIG. 3 is operating as an air conditioner, a heat exchanger 60 in the outdoor unit 58 serves as a condenser for re-condensing vaporized refrigerant flowing from the indoor unit 56 to the outdoor unit 58 via one of the refrigerant conduits 54. In these applications, a heat exchanger 62 of the indoor unit functions as an evaporator. Specifically, the heat exchanger 62 receives liquid refrigerant, which may be expanded by an expansion device, and evaporates the refrigerant before returning it to the outdoor unit 58.

The outdoor unit 58 draws environmental air through the heat exchanger 60 using a fan 64 and expels the air above the outdoor unit 58. When operating as an air conditioner, the air is heated by the heat exchanger 60 within the outdoor unit 58 and exits the unit at a temperature higher than it entered. The indoor unit 56 includes a blower or fan 66 that directs air through or across the indoor heat exchanger 62, where the air is cooled when the system is operating in air conditioning mode. Thereafter, the air is passed through ductwork 68 that directs the air to the residence 52. The overall system operates to maintain a desired temperature as set by a system controller. When the temperature sensed inside the residence 52 is higher than the set point on the thermostat, or a set point plus a small amount, the residential heating and cooling system 50 may become operative to refrigerate additional air for circulation through the residence 52. When the temperature reaches the set point, or a set point minus a small amount, the residential heating and cooling system 50 may stop the refrigeration cycle temporarily.

The residential heating and cooling system 50 may also operate as a heat pump. When operating as a heat pump, the roles of heat exchangers 60 and 62 are reversed. That is, the heat exchanger 60 of the outdoor unit 58 will serve as an evaporator to evaporate refrigerant and thereby cool air entering the outdoor unit 58 as the air passes over outdoor the heat exchanger 60. The indoor heat exchanger 62 will receive a stream of air blown over it and will heat the air by condensing the refrigerant.

In some embodiments, the indoor unit 56 may include a furnace system 70. For example, the indoor unit 56 may include the furnace system 70 when the residential heating and cooling system 50 is not configured to operate as a heat pump. The furnace system 70 may include a burner assembly and heat exchanger, among other components, inside the indoor unit 56. Fuel is provided to the burner assembly of the furnace 70 where it is mixed with air and combusted to form combustion products. The combustion products may pass through tubes or piping in a heat exchanger, separate from heat exchanger 62, such that air directed by the blower 66 passes over the tubes or pipes and extracts heat from the combustion products. The heated air may then be routed from the furnace system 70 to the ductwork 68 for heating the residence 52.

FIG. 4 is an embodiment of a vapor compression system 72 that can be used in any of the systems described above. The vapor compression system 72 may circulate a refrigerant through a circuit starting with a compressor 74. The circuit may also include a condenser 76, an expansion valve(s) or device(s) 78, and an evaporator 80. The vapor compression system 72 may further include a control panel 82 that has an analog to digital (A/D) converter 84, a microprocessor 86, a non-volatile memory 88, and/or an interface board 90. The control panel 82 and its components may function to regulate operation of the vapor compression system 72 based on feedback from an operator, from sensors of the vapor compression system 72 that detect operating conditions, and so forth.

In some embodiments, the vapor compression system 72 may use one or more of a variable speed drive (VSDs) 92, a motor 94, the compressor 74, the condenser 76, the expansion valve or device 78, and/or the evaporator 80. The motor 94 may drive the compressor 74 and may be powered by the variable speed drive (VSD) 92. The VSD 92 receives alternating current (AC) power having a particular fixed line voltage and fixed line frequency from an AC power source, and provides power having a variable voltage and frequency to the motor 94. In other embodiments, the motor 94 may be powered directly from an AC or direct current (DC) power source. The motor 94 may include any type of electric motor that can be powered by a VSD or directly from an AC or DC power source, such as a switched reluctance motor, an induction motor, an electronically commutated permanent magnet motor, or another suitable motor.

The compressor 74 compresses a refrigerant vapor and delivers the vapor to the condenser 76 through a discharge passage. In some embodiments, the compressor 74 may be a centrifugal compressor. The refrigerant vapor delivered by the compressor 74 to the condenser 76 may transfer heat to a fluid passing across the condenser 76, such as ambient or environmental air 96. The refrigerant vapor may condense to a refrigerant liquid in the condenser 76 as a result of heat transfer with the environmental air 96. The liquid refrigerant from the condenser 76 may flow through the expansion device 78 to the evaporator 80.

The liquid refrigerant delivered to the evaporator 80 may absorb heat from another air stream, such as a supply air stream 98 provided to the building 10 or the residence 52. For example, the supply air stream 98 may include ambient or environmental air, return air from a building, or a combination of the two. The liquid refrigerant in the evaporator 80 may undergo a phase change from the liquid refrigerant to a refrigerant vapor. In this manner, the evaporator 80 may reduce the temperature of the supply air stream 98 via heat transfer with the refrigerant. Thereafter, the vapor refrigerant exits the evaporator 80 and returns to the compressor 74 by a suction line to complete the cycle.

In some embodiments, the vapor compression system 72 may further include a reheat coil in addition to the evaporator 80. For example, the reheat coil may be positioned downstream of the evaporator relative to the supply air stream 98 and may reheat the supply air stream 98 when the supply air stream 98 is overcooled to remove humidity from the supply air stream 98 before the supply air stream 98 is directed to the building 10 or the residence 52.

It should be appreciated that any of the features described herein may be incorporated with the HVAC unit 12, the residential heating and cooling system 50, or other HVAC systems. Additionally, while the features disclosed herein are described in the context of embodiments that directly heat and cool a supply air stream provided to a building or other load, embodiments of the present disclosure may be applicable to other HVAC systems as well. For example, the features described herein may be applied to mechanical cooling systems, free cooling systems, chiller systems, or other heat pump or refrigeration applications.

As discussed above, embodiments of the present disclosure are directed to a microchannel heat exchanger, such as an evaporator or a condenser, that includes sinusoidal microchannel tubes that increase the efficiency of thermal energy transfer between a refrigerant flowing through the sinusoidal microchannel tubes and an air flow passing across the microchannel heat exchanger. With the foregoing in mind, FIG. 5 illustrates a side view of an embodiment of a microchannel heat exchanger 100 that may be used in the HVAC unit shown in FIGS. 1 and 2, in the residential heating and cooling system 50 shown in FIG. 3, in vapor compression system as shown in FIG. 4, or any suitable HVAC system. To facilitate discussion, the microchannel heat exchanger 100 and its components may be described with reference to a longitudinal axis or direction 102, a vertical axis or direction 104, and a lateral axis or direction 106.

The microchannel heat exchanger 100 may have a length 112 that extends along the longitudinal direction 102 and a height 114 that extends along the vertical direction 104. A fluid to be conditioned, such as an air flow, may flow transversely along the lateral direction 106 across the microchannel heat exchanger 100. As described in greater detail herein, a refrigerant flowing through the microchannel heat exchanger 100 may be used to transfer thermal energy between the fluid to be conditioned and the refrigerant.

The microchannel heat exchanger 100 may be fluidly coupled to the conduits of a refrigerant circuit or other flow path of an HVAC system at an inlet 118 and an outlet 119. The refrigerant from circuit may flow through the inlet 118 and enter a distribution manifold 120. The distribution manifold 120 may distribute the refrigerant to a plurality of microchannel tubes 122 that extend along the length 112 of microchannel heat exchanger 100. Although six microchannel tubes 122 are included in the microchannel heat exchanger 100, as shown in FIG. 5, any suitable number of microchannel tubes 122 may be included in the microchannel heat exchanger 100. For example, one, two, three, four, five, six, seven, eight, nine, ten, or more microchannel tubes 122 may be included in the microchannel heat exchanger 100. As shown in the illustrated embodiment of FIG. 5, the plurality of microchannel tubes 122 may have a sinusoidal configuration, or a sinusoidal shape, along a length 116 of the plurality of microchannel tubes 122 that extends in the longitudinal direction 102. The sinusoidal shape of the microchannel tubes 122 may generate air resistance to an air flow passing across the heat exchanger 100. The air resistance increases the heat transfer rate between the refrigerant and the air flow because the sinusoidal configuration of the microchannel tubes 122 interrupts the flow of the air across the microchannel heat exchanger 100, thereby maintaining contact between the sinusoidal microchannel tubes 122 and the air flow for a longer period of time than, for example, microchannel tubes with a straight shape or a flat shape.

As further described herein, each microchannel tube 122 may have one or more sinusoidal microchannels formed within the body of each microchannel tube 122. The one or more sinusoidal microchannels may extend along a length of each microchannel tube 122. In certain embodiments, the length of each sinusoidal microchannel may be substantially equal to the length 116 of each sinusoidal microchannel tube 122. As compared to a straight shape or a flat shape, the sinusoidal shape of the microchannels provides a longer flow path of the refrigerant through the microchannel heat exchanger 100 along the tube length 116 between the distribution manifold 120 and a collection manifold 128, thereby increasing the heat transfer area of the sinusoidal microchannels. Additionally, the sinusoidal shape of the microchannels induces turbulence to the flow of the refrigerant through the sinusoidal microchannels, thereby increasing the heat transfer coefficient of the refrigerant within the sinusoidal microchannels as compared to microchannels with a straight shape or a flat shape. The increase in heat transfer area of the sinusoidal microchannels and the increase in the heat transfer coefficient of the refrigerant enhances the heat transfer area of the microchannel heat exchanger 100 and the heat transfer rate between the refrigerant and the air flow passing across the microchannel heat exchanger 100.

Heat exchanger fins 130 may also be disposed between each microchannel tube 122 of the plurality of microchannel tubes 122. The heat exchanger fins 130 may extend along a length 132 of each microchannel tube 122 between the distribution manifold 120 and the collection manifold 128. The heat exchanger fins 130 may physically and thermally connect adjacent microchannel tubes 122 and provide air resistance to the an air flow flowing across the heat exchanger 100. As shown in FIG. 5, the heat exchanger fins 130 may have a sinusoidal shape along the length 132 of the heat exchanger fins 130. The sinusoidal shape of the heat exchanger fins 130 may be different than the sinusoidal shape of the microchannel tubes 122. For example, the sinusoidal shape of the heat exchanger fins 130 may include more crests and/or more troughs than the sinusoidal shape of the microchannel tubes 122 between the distribution manifold 120 and the collection manifold 128. In other embodiments, the heat exchanger fins 130 may have a U-shape, a parabola shape, a triangular shape, a jagged shape, a stepped shape, or any other suitable shape. The air flow may flow transversely along the lateral direction 106 across the microchannel heat exchanger 100 and between the heat exchanger fins 130. The heat exchanger fins 130 increase a heat transfer surface area of the plurality of microchannel tubes 122, which may enable the refrigerant within the plurality of microchannel tubes 122 to exchange thermal energy with the air flow passing across the heat exchanger 100 more effectively.

The distribution manifold 120 may extend across the full height 114 of the microchannel heat exchanger 100, such that the refrigerant is directed to each microchannel tube 122 of the plurality of microchannel tubes 122. The distribution manifold 120 may also extend along a width that is generally parallel to the lateral direction 106. In certain embodiments, the width of the distribution manifold 120 is indicative of the width of the plurality of microchannel tubes 122. The refrigerant may flow through the plurality of microchannel tubes 122 from a first end portion 124 to a second end portion 126 of the microchannel heat exchanger 100. The refrigerant may then be collected in the collection manifold 128 of the microchannel heat exchanger 100 before being directed to main outlet 119. The refrigerant may exit the microchannel heat exchanger 100 and return to the refrigerant circuit or flow path of the HVAC system via the main outlet 120.

In certain embodiments, the microchannel heat exchanger 100 may be a first heat exchanger fluidly coupled and disposed adjacent to a second heat exchanger along the lateral direction 106, which may be self-similar to the first heat exchanger. For example, a width of the first heat exchanger may be disposed adjacent to a width of the second heat exchanger, and main outlet 119 of the first heat exchanger may be fluidly coupled to main inlet 118 of the second heat exchanger. The first heat exchanger and the second heat exchanger may be coupled together via fasteners, such as bolts or clamps, adhesives, such as bonding glue, welding, or any suitable method. In certain embodiments, the first heat exchanger and the second heat exchanger may be disposed parallel with each other. In certain embodiments, a heat exchanger unit may include one, two, three, four, five, six, seven, eight, or more fluidly coupled microchannel heat exchangers 100.

FIG. 6 illustrates a perspective view of a configuration 110 of sinusoidal heat exchanger fins 130 coupled between adjacent sinusoidal microchannel tubes 122 that may be utilized within the microchannel heat exchanger 100 of FIG. 5. As described above, each microchannel tube 122 may have one or more sinusoidal microchannels 136 formed within the body of the respective microchannel tube 122. The sinusoidal shape of the microchannels 136 may correspond to the sinusoidal shape of a respective microchannel tube. For example, each crest and each trough of the sinusoidal shape of a microchannel 136 may substantially align along the longitudinal direction 102 with each crest and each trough of the sinusoidal shape of a respective microchannel tube 122. The one or more sinusoidal microchannels 136 may extend along the length 116 of the respective microchannel tube 122. Additionally, one or more sinusoidal heat exchanger fins 130 may physically and thermally couple adjacent microchannel tubes 122.

The sinusoidal heat exchanger fins 130 may extend along the respective length 116 of the microchannel tube 122 between a first end 108 of the sinusoidal microchannel tubes 122 and a second end 109 of the sinusoidal microchannel tubes 122. In certain embodiments, the length 132 of the sinusoidal heat exchanger fins 130 in the longitudinal direction 102 is less than the length 116 of the sinusoidal microchannel tubes 122. The sinusoidal heat exchanger fins 130 may also extend along a width 150 of the sinusoidal microchannel tubes 122 in the lateral direction 106. In certain embodiments, the width of the sinusoidal heat exchanger fins 130 may be less than the width 150 of the sinusoidal microchannel tubes 122. Additionally, the sinusoidal heat exchanger fins 130 may extend within a space 115 between adjacent sinusoidal microchannel tubes 122, such that each sinusoidal heat exchanger fin 130 couples to each adjacent sinusoidal microchannel tube 122 at a plurality of points along the length 116 of the sinusoidal microchannel tubes 122.

In certain embodiments, the particular sinusoidal shape of the microchannels 136 and/or the microchannel tubes 122 may be selected to optimize the heat transfer efficiency of the microchannel heat exchanger 100, for example, using experimental tests or trials. That is, experimental tests may be used to determine which particular sinusoidal shape or configuration of the microchannels 136 and/or the microchannel tubes 122 provides a suitably efficient or most efficient rate of heat transfer, a suitably efficient or most efficient pressure drop, or both, between refrigerant entering the microchannel heat exchanger 100 through the main inlet 118 and refrigerant exiting the microchannel heat exchanger 100 through the main outlet 119. The experimental testing may include the collection of empirical data, such as temperature measurements, pressure measurements, or both, of the refrigerant taken near the main inlet 118 and the main outlet 119, to determine the desired sinusoidal shape of the microchannels 136, the microchannel tubes 122, and/or the heat exchanger fins 130. The experimental testing may also include modeling operational parameters, such as temperature and pressure, of the microchannel heat exchanger 100.

For example, a desired sinusoidal shape of an embodiment of the microchannel 136 and/or an embodiment of the microchannel tube 122 may be determined based on a desired balance between an enhanced heat transfer area and/or an enhanced heat transfer rate of the microchannel 136 or the microchannel tube 122, a target pressure drop of refrigerant flowing from the first end 108 and the second end 109 of the microchannel 136 or the microchannel tube 122, and/or a target pressure drop of the air flow passing across the heat exchanger 100 in the lateral direction 106. For example, a positive correlation exists between the amplitude, the number of crests, and the number of troughs in the sinusoidal shape of the microchannel 136 or the microchannel tube 122 and the heat transfer area of a microchannel tube 122. That is, an increase in the amplitude, the number of crests, and/or the number of troughs in the sinusoidal shape of the microchannel 136 or the microchannel tube 122 increases the path length traveled by refrigerant flowing through the microchannel 136 or the microchannel tube 122, thereby increasing the heat transfer area of the microchannel tube 122. Additionally, a positive correlation exists between the amplitude, the number of crests, and the number of troughs in the sinusoidal shape of the microchannel 136 or the microchannel tube 122 and the heat transfer rate between refrigerant flowing through the microchannel 136 or the microchannel tube 122 and a heat exchange fluid in contact with the microchannel tube 122. Further, a positive correlation exists between the amplitude, the number of crests, and the number of troughs in the sinusoidal shape of the microchannel 136 or the microchannel tube 122 and the pressure drop from the first end 108 to the second end 109 of the microchannel 136 or the microchannel tube 122. Moreover, a positive correlation may exist between the number of crests and the number of troughs in the sinusoidal shape of the microchannel 136 or the microchannel tube 122 and the pressure drop of air flow across the heat exchanger 100 having the microchannel tube 122, but a negative correlation may exist between the amplitude of the crests and troughs in the sinusoidal shape of the microchannel 136 or the microchannel tube 122 and the pressure drop of air flow across the heat exchanger 100 having the microchannel tube 122.

As a non-limiting example, it may be determined that a desired or target heat transfer efficiency of the microchannel heat exchanger 100 is achieved when each microchannel tube 122 has a sinusoidal shape with two crests, two troughs, and an amplitude of two, as shown in FIGS. 7A and 7B. FIG. 7A is a perspective view of an embodiment of the sinusoidal microchannel tube 122 having a plurality of sinusoidal microchannels 136. The sinusoidal microchannel tube 122 extends the length 116 along the longitudinal direction 102, extends a height 146 along the vertical direction 104, and extends the width 150 along the lateral direction 106. As described above, refrigerant a circuit or flow path of an HVAC system may be distributed to the sinusoidal microchannels 136 within the sinusoidal microchannel tube 122 via the distribution manifold 120 and may be collected by the collection manifold 128 after flowing through the sinusoidal microchannel tube 122. As the refrigerant flows through the sinusoidal microchannel tube 122, a fluid to be conditioned, such as air, may flow transversely along the lateral direction 106 across the sinusoidal microchannel tube 122. As the heat exchange fluid comes into contact with the sinusoidal microchannel tube 122, the refrigerant passing through the sinusoidal microchannel tube 122 may be used to transfer thermal energy between the refrigerant and the heat exchange fluid.

Although the cross-sectional shape of the sinusoidal microchannel tubes, or the sinusoidal microchannel tube bodies, are elongated in the lateral direction 106 in the illustrated embodiment, it should be noted that in other embodiments the cross-sectional shape of the sinusoidal microchannel tubes may be square-shaped, hexagonal-shaped, oval-shaped, elliptical-shaped, trapezoidal-shaped, rectangular-shaped, or any other suitable shape.

As shown in FIG. 7A, the sinusoidal microchannel tube 122 has a plurality of sinusoidal microchannels 136 formed within the body of the sinusoidal microchannel tube 122. Although the depicted embodiment illustrates the sinusoidal microchannel tube 122 as having six sinusoidal microchannels 136, in other embodiments, the sinusoidal microchannel tube 122 may have one, two, three, four, five, seven, eight, or more microchannels 136 formed within the body of the sinusoidal microchannel tube 122. The one or more sinusoidal microchannels 136 may each extend along the length 116 of the microchannel tube 122. Additionally, the length of each sinusoidal microchannel 136 may be substantially equal to the length 116 of the sinusoidal microchannel tube 122 having the sinusoidal microchannels 136. In certain embodiments, each sinusoidal microchannel 136 formed within the sinusoidal microchannel tube 122 is substantially parallel to each other sinusoidal microchannel 136 formed within the sinusoidal microchannel tube 122 in the lateral direction 106.

FIG. 7B is a side view of the sinusoidal microchannel tube 122 of FIG. 7A. In the depicted embodiment, the sinusoidal microchannel tube 122 has a center axis 142 that extends along the length 116 of the sinusoidal microchannel tube 122 in the longitudinal direction 102. As described above, the sinusoidal shape of the microchannel tube 122 of FIGS. 7A and 7B has two crests 140, two troughs 138, and an amplitude of two. Each crest 140 and each trough 138 corresponds to a portion of the sinusoidal microchannel tube 122 that is a desired distance 144 from the center axis 142 of the sinusoidal microchannel tube 122 in the vertical direction 104. The desired distance 144 corresponds to the amplitude of the sinusoidal shape of the microchannel tube 122 and may be measured in micrometers, millimeters, or any other suitable distance unit. For example, an amplitude of two may correspond to a desired distance 144 of two millimeters.

Additionally, the plurality of microchannels 136 may have a similar sinusoidal shape to the sinusoidal shape of the microchannel tube 122. That is, the sinusoidal shape of the plurality of microchannels 136 within the sinusoidal microchannel tube 122 may have the same number of crests and troughs as the sinusoidal shape of the microchannel tube 122 but may have a proportionally smaller amplitude, such that the plurality of microchannels 136 may fit within the body of the sinusoidal microchannel tube 122 along the length 116 of the sinusoidal microchannel tube 122. In certain embodiments, the diameter of each sinusoidal microchannel 136 may be substantially the same along the length of the sinusoidal microchannel 136 in the longitudinal direction 102.

As another non-limiting example, it may be determined that a desired heat transfer efficiency of the microchannel heat exchanger 100 is achieved when the plurality of microchannel tubes 136 has a sinusoidal shape with three crests 140, two troughs 138, and an amplitude of two, as shown in FIGS. 8A and 8B. FIG. 8A is a perspective view of a sinusoidal microchannel tube 152 having a plurality of sinusoidal microchannels 136. As similarly described above, the sinusoidal microchannel tube 152 extends the length 116 along the longitudinal direction 102, extends the height 146 along the vertical direction 104, and extends the width 150 along the lateral direction 106. Refrigerant from a circuit or flow path of the HVAC system may be distributed to the sinusoidal microchannels 136 within the sinusoidal microchannel tube 152 via the distribution manifold 120 and may be collected by the collection manifold 128 after flowing through the sinusoidal microchannel tube 152. As the refrigerant flows through the sinusoidal microchannel tube 152, a fluid to be conditioned, such as air, may flow transversely along the lateral direction 106 across the sinusoidal microchannel tube 152. As an air flow comes into contact with the sinusoidal microchannel tube 152, the refrigerant passing through the sinusoidal microchannel tube 152 may be used to transfer thermal energy between the refrigerant and the air flow.

As shown in FIG. 8A, the sinusoidal microchannel tube 152 has a plurality of sinusoidal microchannels 136 formed within the body of the sinusoidal microchannel tube 152. Although the depicted embodiment illustrates the sinusoidal microchannel tube 152 as having six sinusoidal microchannels 136, in other embodiments, the sinusoidal microchannel tube 152 may have one, two, three, four, five, seven, eight, or more microchannels 136 formed within the body of the sinusoidal microchannel tube 152. The one or more sinusoidal microchannels 136 may extend along the length 116 of the microchannel tube 152. Additionally, the length of each sinusoidal microchannel 136 may be substantially equal to the length 116 of each sinusoidal microchannel tube 152. In certain embodiments, each sinusoidal microchannel 136 formed within the sinusoidal microchannel tube 152 is substantially parallel to each other sinusoidal microchannel 136 formed within the sinusoidal microchannel tube 152 in the lateral direction 106.

FIG. 8B is a side view of the sinusoidal microchannel tube 152 of FIG. 8A. In the depicted embodiment, the sinusoidal microchannel tube 152 has the center axis 142 that extends along the length 116 of the sinusoidal microchannel tube 152 in the longitudinal direction 102. As described above, the sinusoidal shape of the microchannel tube 152 of FIGS. 8A and 8B has three crests 140, two troughs 138, and an amplitude of two. Each crest 140 and each trough 138 corresponds to a portion of the sinusoidal microchannel tube 152 that is the desired distance 144 from the center axis 142 of the sinusoidal microchannel tube 152 in the vertical direction 104. The desired distance 144 corresponds to the amplitude of the sinusoidal shape of the microchannel tube 152 and may be measured in micrometers, millimeters, or any other suitable distance unit. For example, an amplitude of two may correspond to a desired distance 144 of two millimeters. In some embodiments, the desired distance 144 for each crest 140 and each trough 144 from the center axis 142 is substantially equal to each other. In other embodiments, the desired distance 144 for each crest 140 and each trough 144 from the center axis 142 may be different from each other, or the desired distance 144 for a subset of crests 140, troughs 144, or both, from the center axis 142 may be different from each other.

Additionally, the plurality of microchannels 136 may have a similar sinusoidal shape to the sinusoidal shape of the microchannel tube 152. That is, the sinusoidal shape of the plurality of microchannels 136 within the sinusoidal microchannel tube 152 may have the same number of crests and troughs as the sinusoidal shape of the microchannel tube 152 but may have a proportionally smaller amplitude, such that the plurality of microchannels 136 may fit within the body of the sinusoidal microchannel tube 152. In certain embodiments, the diameter of each sinusoidal microchannel 136 may be substantially the same along the length of the sinusoidal microchannel 136 in the longitudinal direction 102.

As another non-limiting example, it may be determined that a desired heat transfer efficiency of the microchannel heat exchanger 100 is achieved when the plurality of microchannel tubes 136 has a sinusoidal shape with two crests 140 and two troughs 138 and an amplitude of three, as shown in FIGS. 9A and 9B. FIG. 9A is a perspective view of a sinusoidal microchannel tube 154 having a plurality of sinusoidal microchannels 136. The sinusoidal microchannel tube 154 extends the length 116 along the longitudinal direction 102, extends the height 146 along the vertical direction 104, and extends the width 150 along the lateral direction 106. Refrigerant from a circuit or flow path of the HVAC system may be distributed to the sinusoidal microchannels 136 within the sinusoidal microchannel tube 154 via the distribution manifold 120 and may be collected by the collection manifold 128 after flowing through the sinusoidal microchannel tube 154. As the refrigerant flows through the sinusoidal microchannel tube 154, a fluid to be conditioned, such as air, may flow transversely along the lateral direction 106 across the sinusoidal microchannel tube 154. As an air flow comes into contact with the sinusoidal microchannel tube 154, the refrigerant passing through the sinusoidal microchannel tube 154 may be used to transfer thermal energy between the refrigerant and the air flow.

As shown in FIG. 9A, the sinusoidal microchannel tube 154 has a plurality of sinusoidal microchannels 136 formed within the body of the sinusoidal microchannel tube 154. Although the depicted embodiment illustrates the sinusoidal microchannel tube 154 having six sinusoidal microchannels 136, in other embodiments, the sinusoidal microchannel tube 154 may have one, two, three, four, five, seven, eight, or more microchannels 136 formed within the body of the sinusoidal microchannel tube 154. The one or more sinusoidal microchannels 136 may extend along the length 116 of the microchannel tube 154. Additionally, the length of each sinusoidal microchannel 136 may be substantially equal to the length 116 of each sinusoidal microchannel tube 154. In certain embodiments, each sinusoidal microchannel 136 formed within the sinusoidal microchannel tube 154 is substantially parallel to each other sinusoidal microchannel 136 formed within the sinusoidal microchannel tube 154 in the lateral direction 106.

FIG. 9B is a side view of the sinusoidal microchannel tube 154 of FIG. 9A. In the depicted embodiment, the sinusoidal microchannel tube 154 has the center axis 142 that extends along the length 116 of the sinusoidal microchannel tube 154 in the longitudinal direction 102. As described above, the sinusoidal shape of the microchannel tube 154 of FIGS. 9A and 9B has two crests 140, two troughs 138, and an amplitude of three. Each crest 140 and each trough 138 corresponds to a portion of the sinusoidal microchannel tube 154 that is the desired distance 144 from the center axis 142 of the sinusoidal microchannel tube 154 in the vertical direction 104. The desired distance 144 corresponds to the amplitude of the sinusoidal shape of the microchannel tube 122 and may be measured in micrometers, millimeters, or any other suitable distance unit. For example, an amplitude of three may correspond to a desired distance 144 of three millimeters.

Additionally, the plurality of microchannels 136 may have a similar sinusoidal shape to the sinusoidal shape of the microchannel tube 154. That is, the sinusoidal shape of the plurality of microchannels 136 within the sinusoidal microchannel tube 154 may have the same number of crests and troughs as the sinusoidal shape of the microchannel tube 154 but may have a proportionally smaller amplitude, such that the plurality of microchannels 136 may fit within the body of the sinusoidal microchannel tube 154. In certain embodiments, the diameter of each sinusoidal microchannel 136 may be substantially the same along the length of the sinusoidal microchannel 136 in the longitudinal direction 102.

As another non-limiting example, it may be determined that a desired heat transfer efficiency of the microchannel heat exchanger 100 is achieved when the plurality of microchannel tubes 136 has a sinusoidal shape with three crests 140 and two troughs 138 and an amplitude of three, as shown in FIGS. 10A and 10B. FIG. 10A is a perspective view of a sinusoidal microchannel tube 156 having a plurality of sinusoidal microchannels 136. The sinusoidal microchannel tube 156 extends the length 116 along the longitudinal direction 102, extends the height 146 along the vertical direction 104, and extends the width 150 along the lateral direction 106. Refrigerant from a circuit or flow path of the HVAC system may be distributed to the sinusoidal microchannels 136 within the sinusoidal microchannel tube 156 via the distribution manifold 120 and may be collected by the collection manifold 128 after flowing through the sinusoidal microchannel tube 156. As the refrigerant flows through the sinusoidal microchannel tube 156, a heat exchange fluid, such as air, may flow transversely along the lateral direction 106 across the sinusoidal microchannel tube 156. As the heat exchange fluid comes into contact with the sinusoidal microchannel tube 156, the refrigerant passing through the sinusoidal microchannel tube 156 may be used to transfer thermal energy between the refrigerant and the heat exchange fluid.

As shown in FIG. 10A, the sinusoidal microchannel tube 156 has a plurality of sinusoidal microchannels 136 formed within the body of the sinusoidal microchannel tube 156. Although the depicted embodiment illustrates the sinusoidal microchannel tube 156 as having six sinusoidal microchannels 136, in other embodiments, the sinusoidal microchannel tube 156 may have one, two, three, four, five, seven, eight, or more microchannels 136 formed within the body of the sinusoidal microchannel tube 156. The one or more sinusoidal microchannels 136 may extend along the length 116 of the microchannel tube 156. Additionally, the length of each sinusoidal microchannel 136 may be substantially equal to the length 116 of each sinusoidal microchannel tube 156. In certain embodiments, each sinusoidal microchannel 136 formed within the sinusoidal microchannel tube 156 is substantially parallel to each other sinusoidal microchannel 136 formed within the sinusoidal microchannel tube 156 in the lateral direction 106.

FIG. 10B is a side view of the sinusoidal microchannel tube 156 of FIG. 10A. In the depicted embodiment, the sinusoidal microchannel tube 156 has a center axis 142 that extends along the length 116 of the sinusoidal microchannel tube 156 in the longitudinal direction 102. As described above, the sinusoidal shape of the microchannel tube 156 of FIGS. 10A and 10B has three crests 140, two troughs 138, and an amplitude of three. Each crest 140 and each trough 138 correspond to a portion of the sinusoidal microchannel tube 156 that is a desired distance 144 from the center axis 142 of the sinusoidal microchannel tube 156 in the vertical direction 104. The desired distance 144 corresponds to the amplitude of the sinusoidal shape of the microchannel tube and may be measured in micrometers, millimeters, or any other suitable distance unit. For example, an amplitude of three may correspond to a desired distance 144 of three millimeters.

Additionally, the plurality of microchannels 136 may have a similar sinusoidal shape to the sinusoidal shape of the microchannel tube 156. That is, the sinusoidal shape of the plurality of microchannels 136 within the sinusoidal microchannel tube 156 may have the same number of crests and troughs as the sinusoidal shape of the microchannel tube 156 but have a proportionally smaller amplitude, such that the plurality of microchannels 136 may fit within the body of the sinusoidal microchannel tube 156. In certain embodiments, the diameter of each sinusoidal microchannel 136 may be substantially the same along the length of the sinusoidal microchannel 136 in the longitudinal direction 102.

As set forth above, embodiments of the present disclosure may provide one or more technical effects enhancing a heat transfer efficiency of a microchannel heat exchanger. For example, the sinusoidal shape or the sinusoidal configuration of the microchannels increases the efficiency of thermal energy transfer between refrigerant flowing through the microchannel tubes and an air flow as compared to microchannel tubes having a straight shape or a flat shape. Specifically, the sinusoidal shape of the microchannels increases the path length traveled by the refrigerant through the microchannel heat exchanger, thereby increasing the heat transfer area of the microchannel tubes. Additionally, the sinusoidal shape of the microchannels induces turbulence to the flow of the refrigerant through the sinusoidal microchannel tubes, thereby increasing the heat transfer coefficient of the refrigerant. Further, the sinusoidal shape of the microchannel tube also generates additional air resistance to the air flow passing across the heat exchanger as compared to microchannel tubes having a straight tube shape or a flat tube shape. This additional air resistance increases the heat transfer rate between the refrigerant and the air flow flowing across the heat exchanger because the air flow remains in contact with the sinusoidal microchannel tubes for a longer period of time than tubes with a straight shape or a flat shape. The technical effects and technical problems in the specification are examples and are not limiting. It should be noted that the embodiments described in the specification may have other technical effects and can solve other technical problems.

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

MICROCHANNEL HEAT EXCHANGER

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