Positive displacement microchannel heat exchanger

Abstract

The present application provides a kind of positive displacement microchannel heat exchanger, which gradually contracts from bottom to top and is sequentially divided into heat exchange section, liquid storage section and liquid addition section.The liquid storage section is a cavity with hollow internal space, the wall surface has one or more slope surfaces, and the slope surfaces are gradually sloped to the liquid addition section.There are two groups of microchannels in the heat exchange section for liquid and refrigerant flow respectively, and refrigerant inlet pipe, refrigerant outlet pipe and liquid inlet pipe are arranged outside the heat exchange section.A communication hole is arranged at the bottom of the internal space of the liquid storage section, and a liquid outlet pipe is arranged at the bottom of the liquid storage section.After heat exchange between liquid and refrigerant in the heat exchange section, the liquid enters the upper liquid storage section, mixes fully and then flows out of the positive displacement microchannel heat exchanger.The positive displacement microchannel heat exchanger is an integral entity made of metal materials such as stainless steel, has compact structure and high heat exchange coefficient, and can significantly reduce the volume and weight of the entire refrigeration system when used as evaporator or condenser in micro refrigeration system.

Description

Technical Field

[0001] This invention relates to a volumetric microchannel heat exchanger, belonging to the field of refrigeration and thermal engineering. Background Technology

[0002] A microchannel heat exchanger is a heat exchanger with microchannels inside, each containing separate channels for the flow and heat exchange of heating and cooling fluids. The equivalent diameter of these microchannels is typically less than 1 mm. Microchannel heat exchangers are commonly used in micro-refrigeration systems, especially portable refrigeration systems, because they offer advantages such as high heat transfer coefficients, high heat transfer efficiency, and compact structure, minimizing system volume while meeting the same heat exchange requirements. In some micro-refrigeration systems (or micro-heat pumps) that cool or heat liquids, in addition to the microchannel heat exchanger, a liquid storage container is also provided, with the two components arranged separately. The presence of the liquid storage container makes it difficult to reduce the size of the micro-refrigeration system, and the connecting pipes between the liquid storage container and the microchannel heat exchanger make the piping layout difficult, prone to leakage, and challenging to assemble and maintain. Summary of the Invention

[0003] To address the problems of difficulty in reducing system size due to the separate arrangement of microchannel heat exchangers and liquid storage containers in existing micro-refrigeration devices, as well as difficulties in pipeline layout and easy liquid leakage, this invention proposes a volumetric microchannel heat exchanger.

[0004] The volumetric microchannel heat exchanger described in this invention is a heat exchanger with liquid storage function. It can be used as an evaporator in a vapor compression refrigeration system to cool the liquid below ambient temperature; it can also be used as a condenser in a vapor compression refrigeration system to heat the liquid above ambient temperature.

[0005] The volumetric microchannel heat exchanger of this invention has a shape that gradually tapers from bottom to top and is sequentially divided into a heat exchange section, a liquid storage section, and a liquid addition section. The heat exchange section, liquid storage section, and liquid addition section are a single, integrated unit, and their material is selected from any one of stainless steel, aluminum alloy, titanium alloy, and copper alloy.

[0006] The liquid feeding section of the volumetric microchannel heat exchanger is a tubular body with internal threads on the inner wall or external threads on the outer wall.

[0007] The liquid storage section of the volumetric microchannel heat exchanger is a cavity with a hollow internal space. Its bottom is connected to the heat exchange section, and its top is connected to the lower opening of the liquid filling section. The outer wall of the liquid storage section has one or more slopes that gradually slope towards the liquid filling section from the bottom to the top.

[0008] At least one connecting hole is provided at the bottom of the internal space of the liquid storage section, and the connecting hole faces the internal space of the liquid storage section. A liquid outlet pipe is also provided at the bottom of the liquid storage section, and the liquid outlet pipe communicates with the internal space of the liquid storage section.

[0009] The heat exchange section of the volumetric microchannel heat exchanger has two sets of staggered but non-interconnected microchannels. The first set of microchannels is for liquid flow, and the second set of microchannels is for refrigerant flow.

[0010] A refrigerant inlet pipe, a refrigerant outlet pipe, and a liquid inlet pipe are also provided outside the heat exchange section. The refrigerant inlet pipe is connected to the inlet of the second set of microchannels inside the heat exchange section, the refrigerant outlet pipe is connected to the outlet of the second set of microchannels inside the heat exchange section, the liquid inlet pipe is connected to the inlet of the first set of microchannels inside the heat exchange section, and the outlet of the first set of microchannels inside the heat exchange section is connected to several connecting holes at the bottom of the internal space of the liquid storage section.

[0011] Furthermore, the heat exchange section of the volumetric microchannel heat exchanger is also equipped with a third refrigerant tube. The third refrigerant tube is connected to the outlet of the second set of microchannels inside the heat exchange section, and a refrigerant filling plug or a refrigerant pressure detection device can be installed on the third refrigerant tube.

[0012] Furthermore, a frustoconical protrusion is provided on the side wall of the liquid storage section of the volumetric microchannel heat exchanger. A temperature sensor mounting hole is provided on the frustoconical protrusion. The temperature sensor mounting hole is connected to the internal space of the liquid storage section for installing a temperature sensor to detect the temperature of the liquid stored inside the liquid storage section.

[0013] Furthermore, several annular protrusions are provided at the bottom of the liquid storage section of the volumetric microchannel heat exchanger, and the annular protrusions are used to fix the volumetric microchannel heat exchanger from the bottom.

[0014] Furthermore, a columnar protrusion is provided on the slope of the liquid storage section of the volumetric microchannel heat exchanger, and a fixing hole is provided on the columnar protrusion. The fixing hole is not connected to the internal space of the liquid storage section. The columnar protrusion and the fixing hole are used to fix the volumetric microchannel heat exchanger from the top.

[0015] Depending on the state of the refrigerant in the heat exchange section, the volumetric microchannel heat exchanger can operate in either evaporator mode or condenser mode. In evaporator mode, the refrigerant evaporates in the heat exchange section, cooling the liquid; in condenser mode, the refrigerant condenses in the heat exchange section, heating the liquid.

[0016] The above technical solution enables an extremely compact structural design. Compared to the separate container and heat exchanger in conventional refrigeration systems, the volumetric microchannel heat exchanger described in this invention integrates liquid storage and heat exchange functions. It can be easily manufactured using additive manufacturing, resulting in a high heat transfer coefficient and eliminating the volume occupied by the container and the connecting pipes between the container and the heat exchanger. This reduction in the number of pipes further reduces the overall size, decreases the complexity of system assembly, lowers the possibility of liquid leakage, and increases system reliability. Consequently, the entire system is easier to assemble, disassemble, and maintain, making it more suitable for portable and embedded applications. Attached Figure Description

[0017] To more clearly illustrate the technical solutions described in this invention, the accompanying drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a perspective view of the volumetric microchannel heat exchanger.

[0019] Figure 2 This is a perspective view of the volumetric microchannel heat exchanger from another angle.

[0020] Figure 3 This is a cross-sectional view (viewed from top to bottom) of the volumetric microchannel heat exchanger in the liquid storage section along the horizontal direction.

[0021] Figure 4 This is a cross-sectional view (viewed from top to bottom) of the volumetric microchannel heat exchanger along the horizontal direction in the heat exchange section.

[0022] Figure 5 This is a cross-sectional view of the volumetric microchannel heat exchanger along the vertical direction. Detailed Implementation

[0023] The embodiments of the present invention will now be further described with reference to the accompanying drawings.

[0024] like Figures 1-2 As shown in a specific embodiment of the present invention, the volumetric microchannel heat exchanger is a heat exchanger with a liquid storage function, which tapers sequentially from bottom to top, with the lower part being the heat exchange section 1, the middle part being the liquid storage section 2, and the top part being the liquid addition section 3. The heat exchange section 1, the liquid storage section 2, and the liquid addition section 3 form a complete entity. The material of the volumetric microchannel heat exchanger is selected from stainless steel, aluminum alloy, titanium alloy, and copper alloy, preferably stainless steel.

[0025] The liquid filling section 3 is a tubular body with an internal thread 3t on the inner wall of the tubular body.

[0026] The liquid storage section 2 is a hollow container with an open top, connected to the heat exchange section 1 at the bottom and the liquid addition section 3 at the top. The liquid storage section 2 has a gradually sloping shape from bottom to top, with the slope gradually sloping towards the liquid addition section 3. The slope can be a single-sided slope or a multi-sided slope. In this embodiment, slope 2p is a single-sided slope, and slope 2q is a multi-sided slope.

[0027] like Figure 3 As shown, at least one connecting hole 2t is provided at the bottom of the internal space 2a of the liquid storage section 2, and the connecting hole 2t faces the interior of the liquid storage section 2. In this embodiment, there are three connecting holes to reduce flow resistance. A liquid outlet pipe 2d is also provided at the bottom of the liquid storage section 2, and the liquid outlet pipe 2d communicates with the internal space 2a of the liquid storage section 2.

[0028] like Figure 1 , Figure 5 As shown, a frustoconical protrusion 2b is also provided on the side wall of the liquid storage section 2, and a temperature sensor mounting hole 2c is provided on the frustoconical protrusion 2b. The temperature sensor mounting hole 2c is connected to the internal space 2a of the liquid storage section 2.

[0029] like Figures 1-5 As shown, several annular protrusions 1f are provided at the bottom of the liquid storage section 1 of the volumetric microchannel heat exchanger. The annular protrusions 1f are used to fix the volumetric microchannel heat exchanger from the bottom.

[0030] A columnar protrusion 2e is provided on one of the slopes 2q of the liquid storage section 2 of the volumetric microchannel heat exchanger. A fixing hole 2f is provided on the columnar protrusion 2e. The fixing hole 2f is not connected to the internal space 2a of the liquid storage section 2. The columnar protrusion 2e and the fixing hole 2f are used to fix the volumetric microchannel heat exchanger from the top.

[0031] like Figure 4 , Figure 5 As shown, the heat exchange section 1 of the volumetric microchannel heat exchanger has two sets of microchannels arranged in an alternating pattern but not connected to each other. The first set of microchannels 1y is for liquid flow, and the second set of microchannels 1r is for refrigerant flow.

[0032] like Figures 1-5 As shown, a refrigerant inlet pipe 1a, a refrigerant outlet pipe 1b, a liquid inlet pipe 1c, and a refrigerant third pipe 1g are provided outside the heat exchange section 1.

[0033] The refrigerant inlet pipe 1a is connected to the inlet of the second set of microchannels 1r inside the heat exchange section 1; the refrigerant outlet pipe 1b is connected to the outlet of the second set of microchannels 1r inside the heat exchange section 1; the liquid inlet pipe 1c is connected to the inlet of the first set of microchannels 1y inside the heat exchange section 1; the outlet of the first set of microchannels 1y inside the heat exchange section 1 is connected to the connecting hole 2t at the bottom of the internal space 2a of the liquid storage section 2; and the refrigerant third pipe 1g is connected to the outlet of the second set of microchannels 1r inside the heat exchange section 1.

[0034] The volumetric microchannel heat exchanger can be used as an evaporator or condenser in a micro vapor compression refrigeration system.

[0035] (a) When the volumetric microchannel heat exchanger is used as an evaporator to cool a liquid:

[0036] The refrigerant inlet pipe 1a is connected to the outlet of the throttling element of the refrigeration system, the refrigerant outlet pipe 1b is connected to the compressor suction port of the refrigeration system, and the refrigerant third pipe 1g can be connected to a refrigerant charging plug or a refrigerant pressure detection device (such as a pressure sensor), thereby forming a complete closed refrigerant circulation loop; the liquid inlet pipe 1c and the liquid outlet pipe 2d are respectively connected to external liquid pipelines, thereby forming a complete closed liquid circulation loop.

[0037] At this point, the low-pressure refrigerant gas-liquid mixture, after being throttled, enters the volumetric microchannel heat exchanger through the refrigerant inlet pipe 1a. It evaporates and absorbs heat in the second set of microchannels 1r, causing the liquid temperature in the adjacent first set of microchannels 1y to decrease. The evaporated low-pressure refrigerant becomes a gas and flows out through the refrigerant outlet pipe 1b, heading towards the suction port of the compressor in the refrigeration system.

[0038] Simultaneously, liquid flows into the first set of microchannels 1y inside the heat exchange section 1 through the liquid inlet pipe 1c. As the liquid flows through the first set of microchannels 1y, heat is absorbed by the refrigerant in the adjacent second set of microchannels 1r, causing the temperature to decrease. The cooled liquid then enters the internal space 2a of the upper liquid storage section 2 through the connecting hole 2t. Here, the cooled liquid is thoroughly mixed, which helps improve the temperature uniformity of the cryogenic liquid and also acts as a temperature buffer. The cryogenic liquid in the liquid storage section 2 then flows out of the volumetric microchannel heat exchanger through the liquid outlet pipe 2d.

[0039] (ii) When the volumetric microchannel heat exchanger is used as a condenser to heat a liquid:

[0040] The refrigerant inlet pipe 1a is connected to the exhaust port of the compressor in the refrigeration system, the refrigerant outlet pipe 1b is connected to the inlet of the throttling element in the refrigeration system, and the refrigerant third pipe 1g can be connected to a refrigerant charging plug or a refrigerant pressure detection device (such as a pressure sensor), thereby forming a complete closed refrigerant circulation loop; the liquid inlet pipe 1c and the liquid outlet pipe 2d are respectively connected to external liquid pipelines, thereby forming a complete closed liquid circulation loop.

[0041] At this time, the high-pressure gaseous refrigerant discharged from the compressor enters the volumetric microchannel heat exchanger through the refrigerant inlet pipe 1a, condenses and releases heat in the second set of microchannels 1r, causing the liquid temperature in the first set of microchannels 1y on the other side to rise. The condensed high-pressure refrigerant becomes liquid and flows out through the refrigerant outlet pipe 1b to the inlet of the throttling element of the external refrigeration system.

[0042] Simultaneously, liquid flows into the first set of microchannels 1y inside the heat exchange section 1 through the liquid inlet pipe 1c. As the liquid flows through the first set of microchannels 1y, it absorbs heat from the refrigerant in the adjacent second set of microchannels 1r, causing its temperature to rise. The heated liquid then enters the internal space 2a of the upper liquid storage section 2 through the connecting hole 2t. Here, the heated liquid is thoroughly mixed, which helps improve the temperature uniformity of the high-temperature liquid and also acts as a temperature buffer. The high-temperature liquid in the liquid storage section 2 then flows out of the volumetric microchannel heat exchanger through the liquid outlet pipe 2d.

[0043] The volumetric microchannel heat exchanger integrates the container and heat exchanger in a conventional refrigeration system, reducing the connecting piping between them. It features a compact structure, small size, and high heat transfer coefficient. When used as an evaporator or condenser in a micro-refrigeration system, it significantly reduces the overall system volume, lowers the possibility of liquid leakage, and simplifies assembly and maintenance. The gradually tapering cross-section allows for additive manufacturing, enabling continuous molding. It can be widely used in portable human body cooling, optoelectronic device cooling, high-power chip cooling, and many other fields.

[0044] The "liquid" mentioned above refers to the liquid being cooled that exchanges heat with the refrigerant, such as water or aqueous solutions. The terms "connected" or "linked" in the text refer to cavities within a material that are interconnected, allowing fluid to flow through them.

[0045] In this document, the directional terms such as front, back, left, right, upper, lower, inner, outer, middle, end, top, bottom, and side are defined according to the positions of the components in the accompanying drawings and between the components, and are only for the purpose of clarity and convenience in expressing the technical solution. It should be understood that the use of these directional terms should not limit the scope of protection claimed in this application.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the principles and rules of the present invention should be included within the protection scope of the present invention.

Claims

1. A volumetric microchannel heat exchanger for heat exchange between refrigerant and liquid, characterized in that: The volumetric microchannel heat exchanger gradually contracts from bottom to top and is divided into a heat exchange section, a liquid storage section, and a liquid addition section in sequence. The heat exchange section, liquid storage section, and liquid addition section are a complete entity. The liquid feeding section of the volumetric microchannel heat exchanger is a tubular body with internal threads on the inner wall or external threads on the outer wall. The liquid storage section of the volumetric microchannel heat exchanger is a cavity with a hollow internal space. Its bottom is connected to the heat exchange section, and its top is connected to the lower opening of the liquid filling section. The outer wall of the liquid storage section has one or more slopes, and the slopes gradually slope towards the liquid filling section. At least one connecting hole is provided at the bottom of the internal space of the liquid storage section, and the connecting hole faces the internal space of the liquid storage section; A liquid outlet pipe is provided at the bottom of the liquid storage section, and the liquid outlet pipe is connected to the internal space of the liquid storage section; The heat exchange section of the volumetric microchannel heat exchanger has two sets of microchannels arranged in an alternating pattern but not connected to each other. The first set of microchannels is for liquid flow, and the second set of microchannels is for refrigerant flow. The refrigerant inlet pipe, refrigerant outlet pipe, and liquid inlet pipe are also provided outside the heat exchange section of the volumetric microchannel heat exchanger. The refrigerant inlet pipe is connected to the inlet of the second set of microchannels inside the heat exchange section, the refrigerant outlet pipe is connected to the outlet of the second set of microchannels inside the heat exchange section, the liquid inlet pipe is connected to the inlet of the first set of microchannels inside the heat exchange section, and the outlet of the first set of microchannels inside the heat exchange section is connected to the connecting hole at the bottom of the internal space of the liquid storage section.

2. The volumetric microchannel heat exchanger according to claim 1, characterized in that: The material of the volumetric microchannel heat exchanger is selected from any one of stainless steel, aluminum alloy, titanium alloy, and copper alloy.

3. The volumetric microchannel heat exchanger according to claim 1, characterized in that: The heat exchange section of the volumetric microchannel heat exchanger is also provided with a third refrigerant tube, which is connected to the outlet of the second set of microchannels inside the heat exchange section. The third refrigerant tube is used to install a refrigerant filling plug or a refrigerant pressure detection device.

4. The volumetric microchannel heat exchanger according to claim 1, characterized in that: The liquid storage section of the volumetric microchannel heat exchanger is also provided with a frustum-shaped protrusion, and a temperature sensor mounting hole is provided on the frustum-shaped protrusion. The temperature sensor mounting hole is connected to the internal space of the liquid storage section.

5. The volumetric microchannel heat exchanger according to claim 1, characterized in that: Several annular protrusions are also provided at the bottom of the liquid storage section of the volumetric microchannel heat exchanger. The annular protrusions are used to fix the volumetric microchannel heat exchanger from the bottom. A columnar protrusion is provided on the slope of the liquid storage section of the volumetric microchannel heat exchanger. A fixing hole is provided on the columnar protrusion. The fixing hole is not connected to the internal space of the liquid storage section. The columnar protrusion and the fixing hole are used to fix the volumetric microchannel heat exchanger from the top.

6. The volumetric microchannel heat exchanger according to claim 1, characterized in that: One application of the volumetric microchannel heat exchanger is as an evaporator for cooling liquids.

7. The volumetric microchannel heat exchanger according to claim 1, characterized in that: One application of the volumetric microchannel heat exchanger is as a condenser for heating liquids.

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