Air conditioner

Abstract

To provide an air conditioner having a freezing damage prevention function for preventing a heat exchange coil from being damaged even when residual water in the heat exchange coil of a heat exchanger is frozen.SOLUTION: A first chamber 21, a second chamber 22 and a partitioning plate 20 for separating the first chamber 21 from the second chamber 22 are installed in a casing 2 of an air conditioner 1. A heat exchanger 4 is disposed in the first chamber 21 so that a peripheral part 29 of an outside air outlet surface 18 of the heat exchanger 4 comes into close contact with an edge of an opening part 23 of the partitioning plate 20. Since this structure causes a straight pipe part 8 and a U-shaped bend part 10 to be exposed to outside air and at the same time to be frozen, generation of unfrozen portion of a heat exchange coil 13 is prevented. As a result, occurrence of freezing damage of the heat exchange coil 13 is prevented.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to an air conditioner.

Background Art

[0002] An air conditioner is a device that circulates outside air and indoor air, and supplies the outside air cooled or heated by a heat exchanger into the room. The air conditioner needs to operate stably regardless of the season. However, especially in cold regions in winter, when the temperature drops below freezing, the water in the heat exchanger coil arranged in the air conditioner freezes, and accidents in which the coil is damaged often occur. Such freezing accidents lead to the suspension of the air conditioning function, and it is necessary to repair or replace the coil, etc. Since it takes time for recovery, it has become an important problem in cold regions.

[0003] In such regions, in order to prevent the freezing of the heat exchanger coil, measures are taken such as using a refrigerant, using a heater for preventing freezing, operating a circulation pump to keep water flowing continuously, or conversely draining water from inside the coil. However, once the water in the coil freezes, the heat exchanger coil may be damaged, or thawing may occur due to the rise in temperature, resulting in water leakage.

[0004] As methods for preventing the freezing of the water inside the heat exchanger coil in winter, there are those disclosed in Patent Documents 1 and 2 below.

[0005] The method for preventing freezing of the heat exchanger disclosed in Patent Document 1 includes a heat exchanger that performs heat exchange between cooling water, which is a heat medium, and air, and a blower. Nitrogen gas is supplied to the coil through which the cooling water flowing through the heat exchanger flows at a predetermined pressure to drain the cooling water inside the coil. After draining the cooling water, the inside of the coil is maintained in a state of being pressurized and sealed with nitrogen gas at a predetermined pressure.

[0006] The method for preventing freezing operation of the cooling heat exchanger disclosed in Patent Document 2 is a method of adjusting the temperature of the outside air at the outlet of the ventilation path of the cooling heat exchanger or the temperature of the anti-freezing water at the outlet of the water passage of the cooling heat exchanger to the set anti-freezing temperature by switching the ventilation and water flow mode of the cooling heat exchanger to the parallel flow mode and adjusting the water flow rate of the anti-freezing water.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] In the method for preventing freezing of the heat exchanger of Patent Document 1, in order to supply nitrogen gas at a predetermined pressure into the coil and drain the cooling water remaining in the coil, it is necessary to provide a nitrogen gas supply source, a supply pipe, and a pressure regulating valve, and adjustments such as making the supply pressure of nitrogen gas during drainage higher than the pressure of nitrogen gas during pressure encapsulation are made. Also, in order to maintain the state where nitrogen gas is pressure-encapsulated in the coil after drainage, it is necessary to continuously supply nitrogen gas.

[0009] The cooling heat exchanger of Patent Document 2 adjusts the opening degree of the anti-freezing control valve based on the detection information of the outlet temperature sensor, and adjusts the water flow rate of the anti-freezing water to the water passage of the cooling heat exchanger, thereby adjusting the temperature of the outside air at the outlet on the ventilation path side of the cooling heat exchanger to the set anti-freezing temperature.

[0010] Furthermore, in the anti-freezing operation, in order to adjust the flow rate of the anti-freezing water flowing through the water passage of the cooling heat exchanger by adjusting the opening degree of the anti-freezing control valve, the adjustment range of the flow rate adjustment is limited to the water volume range in which the flow velocity of the anti-freezing water in the water passage of the cooling heat exchanger is equal to or higher than the set lower limit flow velocity, and the opening degree adjustment range of the anti-freezing control valve is defined as a range equal to or higher than the set lower limit opening degree.

[0011] And the operation control device of the outdoor unit of Patent Document 2 changes the above-mentioned set lower limit opening degree to the increasing side as the temperature of the outside air at the inlet of the ventilation passage of the cooling heat exchanger becomes lower based on the detection information of the inlet temperature sensor that detects the temperature of the outside air.

[0012] That is, in order to perform the anti-freezing operation of the cooling heat exchanger, it is necessary to adjust the water flow rate and its flow velocity based on the information obtained from the temperature sensor that detects the temperature of the outside air.

[0013] However, the anti-freezing method of the heat exchange coil as in Patent Documents 1 and 2 is a countermeasure of adjusting various devices provided in the air conditioner according to the situation each time to prevent freezing, and even if such countermeasures are taken, the corresponding measures in case of freezing are not disclosed.

[0014] Therefore, an object of the present invention is to provide an air conditioner having an anti-freezing destruction prevention function that can prevent the destruction of the coil even if the remaining water in the heat exchanger coil freezes in winter.

Means for Solving the Problems

[0015] The present invention that solves the above problems is as follows.

[0016] (First Aspect) It has a housing, The housing has a partition plate with an opening that divides the first chamber, the second chamber, and the first chamber and the second chamber. A heat exchanger is installed in the first chamber, The heat exchanger has a fin portion formed by laminating a plurality of fins and a heat exchange coil, and exchanges heat between outside air and a circulating liquid flowing through the heat exchange coil. The heat exchange coil is formed with a continuous flow path composed of a straight pipe portion made of a plurality of straight pipes and a U-bend portion made of a plurality of U-bend pipes. Both ends of the heat exchange coil are joined to a header portion. The straight pipe portion is provided so as to penetrate through the fin portion, and the U-bend portion protrudes outward from the fin portion. The cross-section of the straight pipe portion of the pipe is expandable under internal pressure. Outside air enters from the first chamber, passes through the fin portion, enters the second chamber from the opening, and exits from the second chamber. The peripheral portion of the surface on the outside air outlet side of the fin portion is blocked by the edge of the opening. An air conditioner characterized by the above.

[0017] (Function and effect) Heat exchange is performed between outside air and a circulating liquid in the air conditioner. Specifically, the circulating liquid flows through the heat exchange coil of the heat exchanger, and by passing the outside air through the coil, the warmed outside air can be taken into the room. Since the fins of the heat exchanger are laminated in a plurality of layers, a wide passage for outside air can be secured, and the area where heat exchange is performed increases, so it is easy to perform heat exchange efficiently. For this reason, heat exchange is likely to occur in the straight pipe portion of the heat exchange coil through which the fins penetrate, and heat exchange is less likely to occur in the U-bend portion protruding from the fins. In the straight pipe portion of the heat exchange coil of the first aspect, since the cross-section of the pipe is expandable under internal pressure, even if outside air that has dropped below freezing passes through the straight pipe portion and the residual water of the circulating liquid in the coil freezes, and the pressure of the residual water existing in the unfrozen portion rises, the pipe is likely to expand and release the pressure, so it has the effect of easily preventing the pipe from breaking. A plurality of U-bend pipes are joined to the ends of a plurality of straight pipes of the heat exchange coil, and the pipe end faces to which the U-bend pipes are not joined are joined to the header portion, so that a continuous flow path can be formed. The ends of the straight pipes and the header portion can also be joined via a header connection pipe.

[0018] The air conditioner of the present invention has a first chamber, a second chamber, and a partition plate that separates the first chamber and the second chamber, all of which are housed in a housing. Outdoor air enters from the first chamber, passes between the fins of the stacked heat exchangers, passes through the opening of the partition plate, enters the second chamber, and exits the air conditioner from the second chamber. Since the heat exchanger is installed in the first chamber, the entire heat exchanger is exposed to the outdoor air. The edge of the opening of the partition plate covers the peripheral portion of the surface of the fin portion of the heat exchanger on the outdoor air outlet side, so that the outdoor air passes through the fins and enters the second chamber. Therefore, when the outdoor air drops below the freezing point, the entire heat exchanger is cooled. As a result, the outdoor air passes not only through the straight pipe portion where the fin portion is present, but also through the U-bend portion where the outdoor air usually does not pass. The straight pipe portion and the U-bend portion of the heat exchanger coil are cooled uniformly, and the remaining water in the coil freezes uniformly, making it difficult for unfrozen portions to exist. Therefore, it is difficult for the pressure of the remaining water in the unfrozen portion to rise, and the coil is less likely to be damaged by freezing.

[0019] (Second aspect) having a housing, the heat exchanger is installed in the housing, the heat exchanger has a fin portion formed by stacking a plurality of fins and a heat exchange coil, and exchanges heat between outdoor air and a circulating liquid flowing in the heat exchange coil, the heat exchange coil is formed with a continuous flow path composed of a straight pipe portion consisting of a plurality of straight pipes and a U-bend portion consisting of a plurality of U-bend pipes, both ends of the heat exchange coil are joined to a header portion, and the entire U-bend portion and the straight pipe portion are provided within the fin portion, both ends of the heat exchange coil are joined to the header portion, the cross-section of the straight pipe portion is expandable under internal pressure, characterized by an air conditioner.

[0020] (Function and effect) Similar to the first aspect, heat exchange between outdoor air and the circulating liquid is performed inside the air conditioner. Specifically, the circulating liquid flows in the heat exchange coil of the heat exchanger, and the warm outdoor air can be taken into the room by passing the outdoor air through the coil. Since the fins of the heat exchanger are stacked and arranged in multiple layers, a wide passage for the outside air can be secured, and the area where heat exchange occurs increases, making it easy to perform heat exchange efficiently. Different from the first aspect, in the second aspect, the fins penetrate not only the straight pipe portions of the heat exchange coil but also the U-bend portions, and since the fins cover the entire coil, the number of fins increases compared to the first aspect, and heat exchange is more likely to occur in the entire heat exchange coil. In this aspect, when the outside air that has dropped below freezing passes through the fins, the entire U-bend portion and the straight pipe portion of the heat exchange coil through which the fins penetrate simultaneously decrease in temperature, and the entire U-bend portion and the straight pipe portion can be simultaneously frozen, so that unfrozen portions are less likely to occur, pressure increase in the unfrozen portions is less likely to occur, and the coil is less likely to be damaged.

[0021] Similar to the heat exchange coil of the first aspect, since the straight pipes of the straight pipe portions can expand under the internal pressure due to the cross-section of the pipes, when the outside air that has dropped below freezing passes through the straight pipe portions and the residual water of the circulating liquid in the coil freezes, even if the pressure of the residual water existing in the unfrozen portions increases, the pipes are likely to expand and release the pressure, so that the pipes are less likely to be damaged. The heat exchange coil has a plurality of U-bend pipes joined to the ends of a plurality of straight pipes, and the pipe end faces to which the U-bend pipes are not joined are joined to the header portion, so that a continuous flow path can be formed. The ends of the straight pipes and the header portion can also be joined via header connection pipes.

[0022] (Third Aspect) The housing has a first chamber, a second chamber, and a partition plate having an opening that separates the first chamber and the second chamber. The heat exchanger is installed in the first chamber. The outside air enters from the first chamber, passes through the fin portion, enters the second chamber from the opening of the partition plate, and exits from the second chamber. An air conditioner of the second aspect in which the peripheral portion of the surface on the outside air outlet side in the fin portion is blocked by the edge of the opening.

[0023] (Function and Effect) It refers to a form combining the features of the first aspect and the second aspect. That is, the fins of the heat exchanger are inserted into the entire U-bend portion and the straight pipe portion, the first chamber and the second chamber of the air conditioner are separated by a partition plate having an opening, and the heat exchanger is arranged in the first chamber such that the peripheral portion of the surface on the outside air outlet side of the heat exchanger contacts the edge of the opening of the partition plate. In addition to the device of the position of the partition plate, since the entire U-bend portion and the straight pipe portion inserted into the fins are simultaneously exposed to the outside air, it is highly possible to make the entire U-bend portion and the straight pipe portion closer to the same situation than in the first and second aspects, and it is highly possible to cool the straight pipe portion and the U-bend portion more uniformly and freeze them uniformly, and the possibility of generating an unfrozen portion is further reduced, and the destruction due to the pressure increase of the unfrozen portion of the coil is less likely to occur than in the first aspect and the second aspect.

[0024] (Fourth Aspect) The housing has a first chamber, a second chamber, and a partition plate having an opening that separates the first chamber and the second chamber. The heat exchanger is installed in the second chamber. Outside air enters from the first chamber, enters the second chamber from the opening of the partition plate, passes through the fin portion, and exits from the second chamber. An air conditioner of the second aspect in which the peripheral portion of the surface on the outside air inlet side in the fin portion is blocked by the edge of the opening.

[0025] (Function and Effect) It refers to a form different from the third aspect in a form combining the features of the first aspect and the second aspect. That is, the fins of the heat exchanger are inserted into the entire U-bend portion and the straight pipe portion, the first chamber and the second chamber of the air conditioner are separated by a partition plate having an opening, and the heat exchanger is arranged in the second chamber such that the peripheral portion of the surface on the outside air inlet side of the heat exchanger contacts the edge of the opening of the partition plate. The effect of the fourth aspect is the same as that of the third aspect.

[0026] (Fifth Aspect) An air conditioner in a first or second aspect, wherein the cross-section of at least one pipe of the U-bend portion or the header portion is in a shape that can expand under internal pressure.

[0027] (Function and effect) In the fifth aspect, since the cross-section of at least one pipe of the U-bend portion or the header portion is in a shape that can expand under internal pressure, in the heat exchanger of the first or second aspect, in the unlikely event that the straight pipe portion freezes first and there is an unfrozen portion remaining in at least one of the U-bend portion or the header portion, even if the internal pressure of the unfrozen portion rises, since one or both of the pipes of the U-bend portion or the header portion can expand, the increased internal pressure can be released into the pipe, and it has the effect of being less likely to cause the destruction of the coil. The shape that can expand is, for example, an elliptical shape or an oval shape, etc. When expanding into a substantially circular shape such as a perfect circle or a circle, the cross-sectional area becomes large, so the internal pressure easily escapes and the possibility of causing the destruction of the coil is low. Shapes close to a disk such as an elliptical shape or an oval shape are flat and crushed shapes, so when internal pressure is applied, a force is applied in the direction of expanding into a substantially circular shape and increasing the cross-sectional area. Of course, as long as it is a shape that can expand, it is not limited to these.

[0028] (Sixth aspect) An inspection instrument for an air conditioner in a first or second aspect for checking the diameter of the straight pipe portion when the straight pipe portion freezes.

[0029] (Function and effect) According to the sixth aspect, when the straight pipe portion with a cross-section that can expand under internal pressure freezes, it is possible to easily check whether there is a portion where the pipe has expanded, and it has the effect of knowing whether it is necessary to replace or repair the pipe or the heat exchanger. An instrument having a space into which the diameter of the straight pipe can enter is inserted between the stacked fins to check whether the straight pipe portion is swollen. If the instrument can be inserted, it maintains its original shape, and if the instrument cannot be inserted, it can be known that the pipe has expanded and deformed, and it is possible to determine whether to replace or repair the heat exchange coil or the heat exchanger itself.

Effect of the invention

[0030] According to the present invention, even if the water in the heat exchanger coil freezes, an air conditioner that is less likely to cause the coil to break can be provided.

Brief Description of the Drawings

[0031]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

[0032] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Note that the following description and drawings only show one embodiment of the present invention, and the content of the present invention should not be construed as being limited to this embodiment.

[0033] (First Aspect) (Air Conditioning Device) FIG. 1 shows an example of the air conditioning device 1. This air conditioning device 1 has a housing 2, and a filter 3, a heat exchanger 4, and a fan 5 in the housing 2 in order from the windward side. In FIG. 1, the width direction of the housing 2 is X, the depth direction of the housing 2, which is the flow direction of the outside air when passing through the heat exchanger 4, is Y, and the vertical direction of the housing 2 is Z. The housing 2 has an outside air inlet 6 for taking in the outside air and an outside air outlet 7, and the flow of the outside air AF is indicated by an arrow in FIG. 1. In other figures other than FIG. 1, the flow of the outside air shall also be indicated by a white arrow AF. Although not indicated by an arrow, the flow of the outside air AF in the housing 2 flows in the Y direction of FIG. 1. The filter 3 functions to improve the cleanliness of the outside air by removing contaminants contained in the outside air such as dust, gas, and pollen. The outside air after passing through the filter 3 becomes beneficial to the human body and can also maintain the quality of the devices installed in the air conditioning device 1. Since the filter 3 functions to remove contaminants from the outside air, it is desirable for the outside air to pass through the filter 3 before passing through other devices in the air conditioning device, and the installation position of the filter 3 is often installed near the outside air inlet 6 inside the air conditioning device 1. The materials of the filter 3 are generally polyester, moda acrylic, etc., but since it is used according to the particle size of the contaminants to be removed, it is not limited to these. In order to create the flow AF of the outside air, a fan 5 is installed near the outside air outlet of the air conditioning device 1. This fan 5 draws the outside air from inside the air conditioning device 1 to the outside of the air conditioning device 1. Each device has different sizes and the number of installations according to the scale of the air conditioning device 1. For example, the air conditioning device 1 used in a research institute, factory, etc. is of a large scale, and the air conditioning device 1 used in a home, etc. is of a small scale. Generally, as the wind speed of the outside air, it is more preferably 1 to 4 (m / s), and preferably 2 to 3 (m / s), so that the outside air can be sufficiently taken in and heat exchange can be performed efficiently. The air conditioner 1 of this embodiment includes an indoor unit, an outdoor unit, etc., and may be any device that takes in outside air and performs heat exchange. Here, the indoor unit refers to a device that circulates the outside air and the indoor air, and the outdoor unit refers to a device that processes the outside air. The present invention relates to a device for preventing rupture or breakage of a heat exchange coil 13 due to freezing of water present in the heat exchange coils 4 of the indoor unit and the outdoor unit, which are the air conditioners 1, when the outside air temperature drops below freezing in cold regions in winter.

[0034] (Heat exchanger) As shown in FIGS. 2 and 3, the heat exchanger 4 has a substantially rectangular parallelepiped shape, and includes a heat exchange coil 13 composed of a straight pipe portion 8 and a U-bend portion 10, and a header portion 12. Conventionally, the straight pipe portion 8 is inserted into the fin portion 14, and as shown in FIG. 3, the U-bend portion 10 protrudes outward from the fin 15. As shown in FIGS. 8 and 9, it is also possible to connect the straight pipe portion 8 protruding outward from the fin 15 and the header portion 12 with a header connecting pipe 25. In the air conditioner 1, as shown in FIGS. 1 and 2, the outside air inlet surface 17 and the outside air outlet surface 18 of the heat exchange coil 13 are installed at intervals on the XZ plane. The header portion 12 has a first header 31 into which the circulating liquid flows into the heat exchange coil 13 and a second header 32 from which the circulating liquid exits the heat exchange coil 13. In the heat exchanger 4, the circulating liquid flows. As described above, this circulating liquid enters from the first header 31, passes through the header connecting pipe 25, and flows through a continuous flow path formed by joining the straight pipe 9 and the U-bend pipe 11 in the straight pipe portion 8 and the U-bend portion 10, passes through the header connecting pipe 25, and exits from the second header 32. The circulating liquid is, for example, warm water or a refrigerant, but is not limited thereto. The direction of the circulating liquid flowing through the flow path may be either flowing downward from the paper surface in FIG. 2 or flowing upward from the bottom. In order to prevent the freezing of the heat exchange coil 13, water is drained from inside the coil. However, after draining the water, there may be water remaining at the lower part of the heat exchange coil 13 shown in FIG. 2. Here, the lower part refers to the part where the outside air inlet surface 17 and the outside air outlet surface 18 of the heat exchange coil 13 are provided on the XZ plane, that is, when the outside air inlet surface 17 and the outside air outlet surface 18 are installed so as to be orthogonal to the Y direction which is the flow direction of the outside air, it refers to about the lower one-third in the Z direction of the entire heat exchange coil 13. When draining water from the header part 12, it is difficult for water to remain. However, especially when draining water from a pipe connected outward from the header part 12, water tends to remain in the straight pipe 9 and the U-bend pipe 11 at the lower part of the heat exchange coil 13. When the outside air temperature drops below freezing, after draining the water, the water remaining in the pipe of the heat exchange coil 13 is cooled by the outside air and freezes, expanding, causing the water pressure in the unfrozen part of the pipe to rise and the pipe to be damaged.

[0035] (Fin part) The fin part 14 is formed by laminating a plurality of plate-like fins 15, and the outside air inlet surface 17 and the outside air outlet surface 18 are formed by connecting the edges of each of the laminated fins 15. As shown in FIG. 2, for example, the fins 15 are laminated to form a substantially rectangular parallelepiped as a whole, and the housing 16 of the heat exchanger 4 exists around the fin part 14 of this rectangular parallelepiped. The heat exchanger 4 has an outside air inlet surface 17 through which outside air enters and an outside air outlet surface 18 through which outside air exits with a gap therebetween. These two surfaces are surfaces orthogonal to the flow AF of the outside air passing through the fin part 14 and are in a facing position relationship with each other. The size of the fin part 14 varies depending on the scale of the heat exchanger 4. Also, in the present invention, the size of the fin part 14 changes depending on whether the straight pipe part 8 up to the first aspect is covered with the fins 15 or whether the entire U-bend part 10 and the straight pipe part 8 are covered with the fins 15 as in the second and third aspects. Conventionally, as shown in FIG. 8, the fins 15 of the heat exchange coil 13 are attached only to the straight pipe portion 8, and mainly perform heat exchange between the outside air and the circulating liquid in the straight pipe portion 8. As shown in FIG. 4, a plurality of mounting holes 19 through which the straight pipes 9 pass are formed in one fin 15, and the positions of the mounting holes 19 of the respective fins 15 are aligned in a direction perpendicular to the flow AF of the outside air and the outside air passes through between the fins 15. As shown in FIGS. 2 and 3, a plurality of fins 15 are laminated. Since the fins 15 are made of aluminum, they have good heat transfer performance. As long as the heat transfer performance is good, the fins 15 are not limited to being made of aluminum.

[0036] (Straight pipe portion) The straight pipe portion 8 has a plurality of straight pipes 9 and forms a part of the heat exchange coil 13. The major axis (diameter L) of the cross section of the straight pipe 9 is arranged in a direction along the direction of the flow AF of the outside air as shown in FIG. 4. In order to warm and take in the passing outside air with the water in the heat exchange coil 13, the straight pipe 9 used in the heat exchange coil 13 is a copper pipe that is easy to conduct heat, but is not limited to a copper pipe as long as the heat conductivity is high. The cross section of the straight pipe 9 may be circular, but a shape that can be expanded, such as an elliptical shape or an oval shape, is more desirable. Because when adopting the straight pipe portion 8 with an elliptical cross section of the straight pipe 9, even if the water remaining in the straight pipe portion 8 freezes after draining and the unfrozen part expands due to water pressure, the cross section of the straight pipe 9 at that part deforms from an elliptical shape to a substantially circular shape, so the possibility of avoiding the destruction of the straight pipe portion 8 of the heat exchange coil 13 is increased. When adopting a straight pipe 9 with an elliptical cross section, the aspect ratio of the ellipse is preferably such that the minor axis:major axis is 1:1.65 or more, more preferably the minor axis:major axis is 1:2 or more. Within this range, the straight pipe 9 of the heat exchange coil 13 is not destroyed at a certain ratio. The inner surface of the straight pipe 9 may be provided with grooves to increase the surface area for heat exchange and increase the heat conductivity. Although not shown, the end of the straight pipe 9 to which the U-bend pipe 11 is joined is widened, the end of the U-bend pipe 11 is inserted, and it is welded by brazing. The welding method is not limited to brazing, and for example, fusion welding or pressure welding may be adopted. As shown in FIG. 8, in the conventional heat exchange coil 13, the fins 15 are attached only to the straight pipe portion 8, and mainly heat exchange between the outside air and the circulating liquid is performed in the straight pipe portion 8. Therefore, in an environment where the air temperature drops below freezing, the temperature of the straight pipe portion 8 into which the fins 15 are inserted becomes lower than the temperature of the U-bend portion 10 where the fins 15 do not exist, and the straight pipe portion 8 freezes earlier than the U-bend portion 10.

[0037] (U-bend portion) As shown in FIGS. 3 and 8, in the conventional heat exchanger 4, the U-bend portion 10 protrudes from the housing 16 of the heat exchanger 4. In an environment where the air temperature drops below freezing, as described above, the temperature of the straight pipe portion 8 into which the fins 15 are inserted becomes lower than the temperature of the U-bend portion 10 where the fins 15 do not exist, and the straight pipe portion 8 freezes earlier than the U-bend portion 10. As a result, there are portions that freeze (mainly the straight pipe portion 8) and portions that do not freeze (mainly the U-bend portion 10), and breakage of the pipes of the heat exchange coil 13 is likely to occur in the unfrozen portions (mainly the U-bend portion 10). Most of the freezing damage accidents are such that the U-bend pipe 11 tears. When the U-bend pipe 11 tears, it becomes necessary to repair or replace it, and there is a problem that the heat exchanger 4 cannot be used until the corresponding measures are completed.

[0038] (Heat exchange coil) The heat exchange coil 13 exchanges heat between the outside air taken into the air conditioner 1 and the circulating liquid flowing in the heat exchange coil 13 by passing the outside air through the heat exchange coil 13, and the outside air after heat exchange flows into the room. Although not shown here, in winter, the low-temperature outside air and the warm circulating liquid exchange heat, the warmed outside air flows into the room, and the cooled circulating liquid exits from the second header 32 of the header portion 12 of the heat exchange coil 13, and is compressed by a compressor or heated by a boiler, etc., to raise the temperature, and then flows back into the heat exchange coil 13 from the first header 31 of the header portion 12 as a warm circulating liquid. The heat exchange coil 13 forms a continuous flow path with the straight pipe portion 8 and the U-bend portion 10. Both ends of a plurality of adjacent straight pipes 9 are joined by U-bend pipes 11, and the heat exchange coil 13 composed of the straight pipe portion 8, the U-bend portion 10, and the header portion 12 forms a continuous flow path. As shown in FIGS. 9 and 10, it is also possible to join the end of the straight pipe 9 where the U-bend pipe 11 of the straight pipe portion 8 is not joined and the header portion 12 via the header connection pipe 25. For example, in FIGS. 2, 5, 8, and 9, the ends of four straight pipes 9 are joined by three U-bend pipes 11, and the ends of the straight pipes 9 where the U-bend pipes 11 are not joined are joined to the header portion 12 via the header connection pipe 25. The header portion 12 is composed of a first header 31 and a second header 32. The flow paths composed of these four straight pipes 9 and three U-bend pipes 11 overlap vertically from top to bottom in FIG. 2 to form a continuous flow path. That is, a plurality of flow paths composed of four straight pipes 9 and three U-bend pipes 11 are provided in the vertical direction to form a flow path group, and one end of each flow path is joined to the header connection pipe 25 and the first header 31, respectively, and the other end is joined to the header connection pipe 25 and the second header 32, respectively. Although not shown, pipes for flowing the circulating liquid in and out are connected to the outside of the first header 31 and the second header 32, respectively. In this form, the circulating liquid from the header portion 12 can be respectively distributed and introduced into each flow path composed of four straight pipes 9 and three U-bend pipes 11 that overlap vertically from top to bottom of the heat exchanger 4, and heat exchange can be easily performed uniformly from top to bottom of the flow path. Further, in this form, not only is it continuous in the vertical direction, but the heat exchange coil 13 has a thickness in the YZ direction, and heat exchange can be efficiently performed at once. The continuous flow path is not limited to the illustrated form, and may be a flow path formed only by the straight pipe 9 that has no thickness in the YZ direction and is continuous only in the vertical direction and the U-bend pipe 11. Also, all the straight pipes 9 in this form are joined by the U-bend pipes 11, and it may be a long continuous flow path where the U-bend pipes 11 are joined only to one end of the straight pipes 9 at the uppermost and lowermost stages of the heat exchange coil 13 and are joined to the header part 12 via the header connection pipes 25. In the long flow path continuous from the uppermost stage to the lowermost stage of this heat exchange coil 13, there is one joint between the straight pipe part 8 and the first header 31 via the header connection pipe 25, and one joint between the straight pipe part 8 and the second header 32 via the header connection pipe 25. Therefore, compared with the forms such as those in FIGS. 2, 5, and 8, the circulating liquid can flow smoothly to the end of the continuous flow path, making the heat exchange more efficient. The straight pipe 9 of the straight pipe part 8 may have a circular cross-section, or may have a shape such as an ellipse or oval that can expand under internal pressure. However, when adopting a straight pipe part 8 whose cross-section of the straight pipe 9 can expand, as shown in FIG. 4, the minor axis S of the ellipse is perpendicular to the outside air flow AF, and the major axis L of the ellipse is parallel to the outside air flow AF. Therefore, compared with the case of adopting a circular straight pipe 9, the outside air after passing through the straight pipe 9 does not peel off, the air resistance is likely to be reduced, and heat exchange can be more efficiently performed.

[0039] (Partition plate) Inside the air conditioner 1, it is divided by a partition plate 20 into a first chamber 21 into which outside air flows and a second chamber 22 from which the outside air warmed after heat exchange is discharged. As shown in FIG. 5, generally, the partition plate 20 installed in the air conditioner 1 or the outdoor unit is located on the upstream side of the passage of the outside air with respect to the heat exchanger 4. As shown in FIG. 7, an opening 23 that is slightly smaller than the size of the surface on which the fins 15 are arranged is provided so that the outside air passes through the straight pipe portion 8 into which the fins 15 are inserted. As shown in FIGS. 5 to 7, the partition plate 20 located on a plane orthogonal to the flow AF of the outside air allows the outside air to pass only through the fin portion 14 of the heat exchanger 4 and the straight pipe portion 8. The periphery 29 of the outside air inlet surface 17 of the heat exchanger 4, or the periphery 29 of the outside air outlet surface 18 facing it, and the edge of the opening 23 of the partition plate 20 are installed in close contact via a packing 24 or the like. This is to surely guide the outside air to flow into the fin portion 14 and the straight pipe portion 8 and prevent the outside air from leaking to other parts. To install the partition plate 20 in close contact with the heat exchanger 4, not only the packing 24 but also an elastic member having appropriate elasticity, an adhesive, or the like may be used.

[0040] In winter, the cause of the freezing and destruction of the heat exchange coil 13 is that a temperature difference occurs between the straight pipe portion 8 and the U-bend portion 10, so there are portions where freezing occurs (mainly the straight pipe portion 8) and portions where freezing does not occur (mainly the U-bend portion 10). As a result, in the unfrozen portions (mainly the U-bend portion 10), the water pressure of the remaining water increases, and the pipes of the heat exchange coil 13 are likely to be damaged. Since the water pressure in the unfrozen portions is higher than the pressure increase in the frozen portions, the applicant has confirmed by experiments that the heat exchange coil 13 does not break at the frozen portions, and the freezing and destruction occurs at the unfrozen portions. Therefore, the applicant considered that if the structure is such that the temperature difference between the straight pipe portion 8 and the U-bend portion 10 is eliminated and the unfrozen portions themselves are not created, then since there are no unfrozen portions, the freezing and destruction is less likely to occur.

[0041] In the case of the positional relationship between the conventional partition plate 20 and the heat exchanger 4 shown in Fig. 5, since there is an opening 23 in the partition plate 20, a temperature difference occurs between the straight pipe portion 8 located on the ventilation path and the U-bend portion 10 shielded from ventilation by the partition plate 20. Therefore, the straight pipe portion 8 is more likely to freeze before the U-bend portion 10. When the straight pipe portion 8 freezes and the U-bend portion 10 remains unfrozen, the pipe is likely to break. For this reason, if the entire heat exchange coil 13 is cooled so that all the pipes freeze simultaneously, the pressure does not rise at a specific location and it is difficult to cause breakage. The first aspect corresponds to such a structure. Since it only changes the position of the conventional partition plate 20, it is easy to manufacture. In the first aspect, as shown in Fig. 6, since the partition plate 20 is installed on the downstream side of the outside air passage with respect to the heat exchanger 4, the heat exchanger 4 that was conventionally located in the second chamber 22 is now located in the first chamber 21. Not only the straight pipe portion 8 of the heat exchanger 4 coil but also the U-bend portion 10 is exposed to the outside air. The outside air also passes through the U-bend portion 10 that was conventionally shielded by the partition plate 20 and through which the outside air did not pass. The straight pipe portion 8 and the U-bend portion 10 of the heat exchanger 4 coil are cooled uniformly and freeze uniformly. That is, when the outside air drops below the freezing point, both the straight pipe portion 8 and the U-bend portion 10 have their temperatures drop, and the remaining water in the pipe freezes. For this reason, it is highly possible to prevent the phenomenon that used to occur, where the straight pipe portion 8 is cooled before the U-bend portion 10, the water in the straight pipe portion 8 freezes and expands, the pressure of the unfrozen remaining water in the U-bend portion 10 rises, and the U-bend portion 10 is damaged.

[0042] (Second aspect) Another structure that cools the entire heat exchange coil 13 so that all the pipes freeze simultaneously corresponds to the second aspect. As shown in Fig. 10, fins 15 are attached not only to the straight pipe portion 8 but also to the U-bend portion 10, and the entire heat exchange coil 13 is inserted into the fins 15. When comparing the first aspect with the second aspect, the heat exchange coil 13 is the same device. The position of the partition plate 20 is different. It may be the same position as the partition plate 20 of the conventional air conditioner 1, but it is not limited to this, and it may be a different position. For example, it may be arranged on the outside air inlet surface 17 side of the heat exchanger 4, or it may be arranged on the outside air outlet surface 18 side of the heat exchanger 4. Since the number of stacked fins 15 increases compared to the first aspect, the size of the fin portion 14 becomes larger, and the heat exchanger 4 is also different from the first aspect. In the second aspect, by providing aluminum fins 15 up to the U-bend portion 10 of the heat exchange coil 13, the straight pipe portion 8 and the U-bend portion 10 are used as the heat exchange portions between the outside air and water. As shown in FIG. 10, the straight pipe portion 8 and the U-bend portion 10 are included in the fin portion 14. In this aspect, the temperatures of the straight pipe portion 8 and the U-bend portion 10 of the heat exchange coil 13 into which the fins 15 are inserted decrease simultaneously, and the straight pipe portion 8 and the U-bend portion 10 can be frozen simultaneously. Therefore, a pressure increase at a specific location is less likely to occur, and the coil is less likely to be damaged. The temperatures of the straight pipe portion 8 and the U-bend portion 10 become close, and they are frozen simultaneously, making it easy to prevent water confinement, and the water pressure is less likely to increase, and the pipe is less likely to be damaged.

[0043] (Third aspect) The third aspect combines the characteristics of the first and second aspects, and a cross-sectional view of the air conditioner 1 is shown in FIG. 11. The heat exchange coils 13 of the first, second, and third aspects are the same device. The same point between the first aspect and the third aspect is the position of the partition plate 20. In the third aspect, similar to the first aspect, the outside air passes through the straight pipe portion 8 and the U-bend portion 10 of the heat exchange coil 13 after passing through the opening 23 of the partition plate 20. The same point between the second aspect and the third aspect is that the number of stacked fins 15 in the heat exchanger 4 is increased. Therefore, the second and third aspects are equipped with the same heat exchanger 4. In the third aspect, as shown in FIGS. 10 and 11, the straight pipe portion 8 and the U-bend portion 10 are included in the fin portion 14. Also, as can be seen from FIG. 11, since the outside air passes through the entire heat exchange coil 13 in the heat exchanger 4 and fins 15 are inserted into the straight pipe portion 8 and the U-bend portion 10, it becomes easier to freeze the straight pipe portion 8 and the U-bend portion 10 simultaneously more reliably, it is possible to prevent the confinement of residual water, it is less likely to cause an increase in water pressure, and furthermore, it is less likely to prevent the rupture of the pipe.

[0044] (Fourth aspect) The fourth aspect is a mode that combines the features of the first and second aspects and is a mode different from the third aspect. The cross-sectional view of the air conditioner 1 is shown in FIG. 11. The heat exchange coils 13 of the first, second, third, and fourth aspects are the same device. The same point between the first aspect and the fourth aspect is the position of the partition plate 20. In the fourth aspect, similar to the first aspect, the outside air passes through the straight pipe portion 8 and the U-bend portion 10 of the heat exchange coil 13 after passing through the opening 23 of the partition plate 20. The same point between the second and third aspects and the fourth aspect is that the number of stacked fins 15 in the heat exchanger 4 is increased. Therefore, the second, third, and fourth aspects are provided with the same heat exchanger 4. In the fourth aspect, as shown in FIGS. 10 and 12, the straight pipe portion 8 and the U-bend portion 10 are included in the fin portion 14. Also, as can be seen from FIG. 12, the outside air that has entered the first chamber 21 passes through the opening 23 of the partition plate 20 and heads towards the second chamber 22 and passes through. Therefore, the outside air surely passes through the fin portion 14 of the heat exchange coil 13 in the heat exchanger 4 in a concentrated manner. Furthermore, since fins 15 are inserted into the straight pipe portion 8 and the U-bend portion 10, it becomes easier to freeze the straight pipe portion 8 and the U-bend portion 10 simultaneously more reliably, it is possible to prevent the confinement of residual water, it is less likely to cause an increase in water pressure, and furthermore, it is less likely to prevent the rupture of the pipe.

[0045] (Fifth aspect) The applicant conducted experiments and confirmed that when water is enclosed in a straight pipe 9 with one end open and a U-bend pipe 11 and uniformly frozen, water overflows from the end of the open straight pipe 9 and the coil is not frozen and damaged. From this, it was found that if there is a place for the pressure of the trapped water to escape, even if the water pressure of the remaining water increases, it is difficult for the heat exchange coil 13 to be damaged. In the fifth aspect, in order to provide a place for the water pressure to escape, the cross-sectional shape of the pipe of the U-bend portion 10 or the header portion 12 of the heat exchange coil 13 in the first or second aspect is made into a shape with an enlarged internal volume such as an elliptical shape or a oval shape. As an example, in FIG. 13, the cross-sectional shape of the pipe of the header portion 12 of the heat exchange coil 13 in the first aspect is made into a shape with an enlarged internal volume such as an elliptical shape or a oval shape. In FIG. 14, the cross-sectional shape of the pipe of the header portion 12 of the heat exchange coil 13 in the second aspect is made into a shape with an enlarged internal volume such as an elliptical shape or a oval shape. As a result of the increase in the water pressure of the U-bend portion 10 or the header portion 12, for example, the elliptical U-bend portion 10 or the header portion 12 becomes substantially circular, and the pressure escapes to the enlarged place, so it is easier to avoid breakage. The cross-sectional shape of the pipe of the heat exchange coil 13 only needs to be deformable so that the volume increases, and is not limited to an elliptical shape or a oval shape. Shapes close to a disk such as an elliptical shape or a oval shape are flattened and crushed shapes, so when internal pressure is applied, a force is applied in a direction in which it bulges into a substantially circular shape and the cross-sectional area increases. The breakage of the pipe of the heat exchange coil 13 in the unfrozen part is due to the increase in the pressure of the water remaining without freezing. Therefore, in order to relieve this pressure increase, at least one of the U-bend portion 10 or the header portion 12, which is the unfrozen part, preferably has a shape that has a high possibility of releasing the increased pressure. If both the U-bend portion 10 and the header portion 12 are pipes with deformable shapes, the place where the pressure escapes further increases compared to the case of a pipe with a deformable shape for only one of them, which is more desirable.

[0046] (Sixth Aspect) As a method for checking the deformation of the tubes of the heat exchange coil 13 due to an increase in water pressure, an instrument 26 as shown in FIG. 15 can be used. This instrument 26 may be an instrument having a handle 27 which is a handle and a checking portion 28 having a space slightly larger than or substantially the same size as the diameter of the tube of the heat exchange coil 13 for checking the diameter of the tube of the heat exchange coil 13. For example, a wrench or the like corresponds to this, but it is not limited to a wrench as long as it can check the deformation of the tube of the heat exchange coil 13. For example, when a straight tube 9 having an elliptical cross section is adopted in the heat exchange coil 13, when an instrument 26 having a space slightly larger than or substantially the same length as the minor axis S of the ellipse as shown in FIG. 15(b) is inserted into the straight tube 9 as shown in FIG. 15(a), as shown in FIG. 15(c), if the minor axis S of the straight tube 9 does not fit into the space of the instrument 26, it can be seen that the straight tube 9 has expanded due to water pressure. Although not shown, when an instrument 26 having a space slightly larger than the major axis L of the ellipse is inserted into the straight tube 9, if the space between the instrument 26 and the straight tube 9 has widened, it can be seen that the straight tube 9 has expanded due to water pressure. Here, a method for checking the diameter of the straight tube 9 of the heat exchange coil 13 has been described, but it is not limited to the straight tube 9. When a U-bend tube 11 having an elliptical cross section is adopted, the deformation of the U-bend tube 11 may be checked by the same method. Also, when a header portion 12 having an elliptical cross section is adopted, the deformation of the header portion 12 can also be checked by the same method. Once expanded by water pressure, the cross section of the tube of the heat exchange coil 13 that has been deformed will not return to its original elliptical shape. Therefore, if freezing of the remaining water occurs again, resulting in an increase in water pressure and the deformed tube cannot withstand the increase, the heat exchange coil 13 will be destroyed. For this reason, before the heat exchange coil 13 reaches destruction, inspection can be performed with the instrument 26, the replacement timing of the heat exchange coil 13 can be grasped, and countermeasures can be taken before the air conditioner 1 breaks down.

Industrial Applicability

[0047] The present invention is suitable for preventing freezing damage in the heat exchange coil of a heat exchanger provided in an air conditioner or an outdoor unit in winter as in the above example.

Explanation of Reference Numerals

[0048] 1... air conditioner, 2... housing of the air conditioner, 3... filter, 4... heat exchanger, 5... fan, 6... outside air inlet, 7... outside air outlet, 8... straight pipe portion, 9... straight pipe, 10... U-bend portion, 11... U-bend pipe, 12... header portion, 13... heat exchange coil, 14... fin portion, 15... fin, 16... housing of the heat exchanger, 17... outside air inlet surface, 18... outside air outlet surface, 19... mounting hole, 20... partition plate, 21... first chamber, 22... second chamber, 23... opening, 24... packing, 25... header connecting pipe, 26... appliance, 27... handle, 28... confirmation portion, 29... peripheral portion, 31... first header, 32... second header, S... minor diameter, L... major diameter

Claims

1. having a housing, the housing has a first chamber, a second chamber, and a partition plate having an opening for partitioning the first chamber and the second chamber, a heat exchanger is installed in the first chamber, the heat exchanger has a fin portion formed by stacking a plurality of fins and a heat exchange coil, and exchanges heat between outside air and a circulating liquid flowing in the heat exchange coil, the heat exchange coil has a flow path formed by a straight tube portion composed of a plurality of straight tubes and a U-bend portion composed of a plurality of U-bend tubes, both ends of the heat exchange coil are joined to a header portion, the straight tube portion is provided so as to penetrate inside the fin portion, and the U-bend portion protrudes outward from the fin portion, the cross-section of the straight tube portion is expandable under internal pressure, outside air enters from the first chamber, passes through the fin portion, enters the second chamber from the opening, and exits from the second chamber, the peripheral portion of the surface on the outside air outlet side in the fin portion is blocked by the edge of the opening, An air conditioner characterized by the above.

2. having a housing, a heat exchanger is installed in the housing, the heat exchanger has a fin portion formed by stacking a plurality of fins and a heat exchange coil, and exchanges heat between outside air and a circulating liquid flowing in the heat exchange coil, the heat exchange coil has a flow path formed by a straight tube portion composed of a plurality of straight tubes and a U-bend portion composed of a plurality of U-bend tubes, both ends of the heat exchange coil are joined to a header portion, the entire U-bend portion and the straight tube portion are provided inside the fin portion, both ends of the heat exchange coil are joined to the header portion, the cross-section of the straight tube portion is expandable under internal pressure, An air conditioner characterized by the above.

3. The housing has a first chamber, a second chamber, and a partition plate having an opening that separates the first chamber and the second chamber. The heat exchanger is installed in the first chamber. Outside air enters from the first chamber, passes through the fin portion, enters the second chamber from the opening of the partition plate, and exits from the second chamber. The air conditioner according to claim 2, wherein the periphery of the surface of the fin portion on the outside air outlet side is blocked by the edge of the opening.

4. The housing has a first chamber, a second chamber, and a partition plate having an opening that separates the first chamber and the second chamber. The heat exchanger is installed in the second chamber. Outside air enters from the first chamber, enters the second chamber from the opening of the partition plate, passes through the fin portion, and exits from the second chamber. The air conditioner according to claim 2, wherein the periphery of the surface of the fin portion on the outside air inlet side is blocked by the edge of the opening.

5. The air conditioner according to claim 1 or 2, wherein the cross-section of at least one of the pipes of the U-bend portion or the header portion is in a shape that can expand under internal pressure.

6. An inspection instrument for the air conditioner according to claim 1 or 2, for checking the diameter of the straight pipe portion when the straight pipe portion is frozen.

Images