JP4849086B2 - Refrigeration cycle equipment, refrigeration / air conditioning equipment, hot water supply equipment - Google Patents

Description

  The present invention relates to an evaporator frosting in a refrigeration cycle used for air conditioners such as room air conditioners, packaged air conditioners and multi air conditioners for buildings, low temperature equipment such as refrigerators, unit coolers and showcases, hot water heaters such as heat pump water heaters, etc. This is related to technology that improves performance through countermeasures.

  In the conventional refrigeration cycle system, the fin used for the evaporator has not been subjected to surface treatment for improving the performance during frost formation. If frost adheres to the evaporator, heat exchange between the refrigerant and the air in the heat exchanger is not performed well, resulting in poor operating efficiency. It was a wasteful defrosting operation that had nothing to do with the work of the evaporator to melt, and it consumed enormous energy. On the other hand, a technique for providing an adsorbent on the surface of the heat transfer surface of the heat exchanger and improving the heat transfer performance is known. (For example, see Patent Document 1)

  Further, the conventional refrigeration cycle apparatus uses a plasma etching method to delay frost formation by applying a surface treatment that imparts water repellency and fine irregularities to the fins (see, for example, Patent Document 2).

  In addition, the conventional refrigeration cycle apparatus heat-exchanges the hydrophilic or water-repellent coating layer on the substrate surface with plasma irradiation to form fine irregularities and make the fin surface super-hydrophilic or super-water-repellent. It is used as a fin of the vessel, and the frost formation is delayed by improving hydrophilicity and water repellency and enhancing water drainage (for example, see Patent Document 3).

Japanese Patent Laying-Open No. 2005-127683 (FIG. 1, column 0016) Japanese Patent No. 3045384 (FIGS. 1 and 2) JP 2002-90084 A (FIGS. 2 and 4)

  In the conventional refrigeration cycle apparatus, the fin used for the evaporator has not been subjected to surface treatment for improving the performance at the time of frost formation. When frosting occurs, the position where moisture in the air condenses and adheres to the evaporator surface as water droplets is not specified, so water droplets are likely to coalesce and solidify after becoming large water droplets. There was a problem that the wind path pressure loss due to the unevenness was increased and the performance during frosting was deteriorated.

  In addition, the conventional refrigeration cycle equipment uses a special processing method such as a plasma etching method to perform surface treatment with water repellency and fine irregularities to achieve frosting delay due to drainage, and has a wide heat transfer area. It takes a very long time to process a large number of fins, and there is a problem that it is difficult to apply to an actual heat exchanger in view of manufacturing cost and manufacturing time. In addition, the conventional refrigeration cycle apparatus cannot be effective unless it is hydrophilic or water repellent, and when applied to the fins of a normal heat exchanger, it changes between hydrophilicity and water repellency over time. Therefore, there is a problem that it is difficult to maintain the same effect.

  In addition, in conventional heat exchangers, the adsorption capacity is increased and the adsorption / desorption speed is improved by the pores on the fin surface, and the adsorption capacity is further increased by supporting an adsorbent such as silica gel on the heat transfer surface. If so. However, if a large amount of adsorbent such as silica gel is supported on the heat transfer surface, there is a problem that the adsorbent is managed so as not to peel off during operation. Since it is formed by anodic oxidation on top, such pores easily react with moisture in the air and clog with time, so the desired pore size cannot be stably obtained. In addition to being unable to obtain sufficient adsorption performance, there was also a problem in stability over time.

  The present invention has been made to solve the above-described problems. When a large number of pores distributed in the evaporator are provided and frost formation occurs on the surface of the evaporator, moisture in the air remains as small water droplets. An object of the present invention is to obtain an apparatus that eliminates waste of energy, for example, by improving the performance at the time of frost formation by coagulating, and by extending the interval of defrost operation.

  Another object of the present invention is to obtain an apparatus that can be manufactured at low cost without using a moisture adsorbent in a heat exchanger such as an air conditioner having a large heat transfer area, and can save energy.

  The refrigeration cycle apparatus according to the present invention includes a compressor, a condenser or a gas cooler, an expansion unit, a refrigerant cycle that connects the evaporator and circulates the refrigerant, a blowing unit that blows air to the evaporator, and a metal that constitutes the evaporator Pores opened from the surface of the fin to the inside with the distance between them being 0.1 mm or less, and pore opening ridge lines uniformly distributed over the surface of the metal fin forming the opening corners of the pores , With.

  The refrigeration cycle apparatus according to the present invention comprises a compressor, a condenser or a gas cooler, an expansion means, an evaporator, a refrigerant cycle for circulating the refrigerant, a blower means for blowing air to the evaporator, and an evaporator. The oxide film is anodized with a metal part such as aluminum having a valve action as an anode, and the pores are formed with a distance between the pores of 0.1 μm or less, distributed on the surface of the evaporator The shape of the opening ridge line of a large number of formed pores is maintained by heat treatment after anodization.

  The refrigeration cycle apparatus according to the present invention makes it difficult for water droplets generated by condensation of moisture in the air to the evaporator surface to form large water droplets, and to reduce the water droplets when solidification occurs, thereby reducing thin frost By forming a layer, air path pressure loss can be reduced, performance during frosting can be improved, and energy can be saved.

Embodiment 1 FIG.
The structure of Embodiment 1 of this invention is demonstrated using figures. FIG. 1 is a refrigerant circuit diagram of the refrigeration cycle apparatus of the first embodiment. In the figure, 11 is an outdoor unit, 12 is an indoor unit, the outdoor unit 11 includes a compressor 21, an outdoor heat exchanger 22, and an outdoor heat exchanger blower 23. The indoor unit 12 is an expansion means such as an expansion valve. 24, the indoor heat exchanger 25, and the indoor heat exchanger blower 26 are provided. In the refrigerant circuit of FIG. 1, the outdoor heat exchanger 22 operates as a condenser and the indoor heat exchanger 25 operates as an evaporator, and is used as a low-temperature device such as a unit cooler or a showcase or an air-conditioning device such as an air conditioner. It is the form seen. FIG. 1 shows an example in which a plurality of indoor units 12 are provided. In FIG. 1, the configuration is described in which the indoor heat exchanger 25 and the outdoor heat exchanger 22 are separated into the room and the outdoor space. The configuration effect of the invention is similarly established.

  In this refrigerant circuit, the refrigerant compressed to a high temperature and high pressure by the compressor 21 is condensed and dissipated by the outdoor heat exchanger 22 by the action of the outdoor heat exchanger blower 23, and is then discharged from the outdoor unit 11 to the indoor unit. 12 flows in. The refrigerant that has entered the indoor unit 12 is expanded by the expansion means 24 to become a low-temperature and low-pressure refrigerant, is evaporated by the action of the indoor heat exchanger blower 26 in the indoor heat exchanger 25, absorbs heat from the indoor air, It leaves the machine 12 and returns to the compressor 21 of the outdoor unit 11 again. Therefore, when this refrigeration cycle apparatus is used for an air conditioner, the indoor unit performs a cooling operation for cooling indoor air.

  For example, when the indoor unit 12 is a unit cooler and is used for refrigeration, the air temperature around the unit cooler is about 0 ° C., and the refrigerant evaporation temperature is about −10 ° C. When the unit cooler 12 is for refrigeration, the air temperature around the unit cooler is about −20 ° C., and the evaporation temperature of the refrigerant is about −30 ° C. Regardless of whether the unit cooler is for refrigeration or refrigeration, the surface temperature of the evaporator, that is, the pipes and fins of the indoor heat exchanger 25 is 0 ° C. or lower, lower than the ambient air temperature, and below freezing point. Therefore, water vapor in the air accumulates as frost around the indoor heat exchanger 25, that is, forms frost. When it is for refrigeration and the ambient air around the indoor heat exchanger 25 is 0 ° C. or higher, water vapor in the air condenses, adheres as water droplets to the surface of the indoor heat exchanger 25, and then solidifies into frost. On the other hand, in the case of refrigeration, since the ambient air around the indoor heat exchanger 25 is 0 ° C. or less, water vapor in the air sublimates and deposits directly on the surface of the indoor heat exchanger 25 as frost.

  Thus, although the process leading to frost is different between refrigeration and freezing, frost formation on the indoor heat exchanger 25 obstructs heat exchange between the refrigerant and the air in any case. When the amount of frost formation increases, the thermal resistance of the indoor heat exchanger 25 increases, the heat exchange performance decreases, and the efficiency of the equipment deteriorates. Further, when the amount of frost formation increases, the flow resistance of the air flowing around the indoor heat exchanger 25 increases due to the action of the blower 26 for the indoor heat exchanger, the air flow decreases, and the unit cooler 12 maintains the prescribed cooling capacity. The ambient air temperature rises. When the ambient air temperature of the unit cooler 12 rises, there is a problem in terms of maintaining the quality of food, so the unit cooler 12 is provided with a defrosting means, and the frost around the evaporator is periodically melted by defrosting. Remove. In the case of a unit cooler, the defrosting means is generally performed by energizing and heating a heater installed in the vicinity of the evaporator. In addition, off-cycle defrosting that stops the flow of refrigerant until the frost melts, or compression Channel switching means such as hot gas defrost for introducing the high-temperature and high-pressure refrigerant at the outlet side of the machine 21 into the indoor heat exchanger 25, or a four-way valve for switching the refrigerant flow path and flowing the high-temperature and high-pressure refrigerant to the evaporator. In the case of an attached air conditioner, reverse defrost is used to reverse the refrigerant flow.

  The present invention relates to air conditioners such as room air conditioners, packaged air conditioners and multi air conditioners for buildings, low temperature equipment such as unit coolers and showcases, and hot water heaters such as heat pump water heaters. This is related to technology that controls the thickness, improves the performance during frost formation, and saves energy. In the present invention, when a large number of pores are provided in a fin used in an evaporator, a refrigerant having a temperature of 0 ° C. or less is supplied to the evaporator, and when frosting occurs on the surface of the evaporator, Since the water droplets are condensed on the ridgeline of the pores or inside the pores and adhere as water droplets, the distance between the water droplets is secured at a constant value, and the coalescence of the water droplets hardly occurs, and the water droplets coagulate as small water droplets. A clean frost layer is formed, air path pressure loss is reduced, performance during frost formation is improved, and a refrigeration cycle apparatus that saves energy is obtained. The frost accumulated on the surface of the indoor heat exchanger 25 operating as an evaporator is a porous layer of ice and air. Hereinafter, the process of forming frost around the evaporator will be described with reference to FIG. 2 and FIG.

  When the air is cooled on the cooling surface (vaporizer surface) and cooled to below the dew point (saturation temperature), mist is formed near the cooling surface, which deposits as water droplets (condensed droplets) on the cooling surface. Adhere to the cooling surface. When water droplets are generated on the cooling surface, they become nuclei that grow and increase in size. At that time, as shown in FIG. 2, when a special surface treatment is not applied to the cooling surface, water droplets are arbitrarily generated everywhere on the cooling surface ((a)). Therefore, there are places where the distance between water droplets is short and places where the distance is long. When water droplets grow and become so large that adjacent water droplets come into contact with each other, the water droplets merge to form a large water droplet ((b), (c)). However, since the water droplets on the cooling surface include a portion where the distance between the water droplets is short and a portion where the distance between the water droplets is short, the water droplets at the portion where the distance is short are combined to easily generate a large water droplet. The water droplets are further cooled and solidified on the cooling surface, forming ice droplets, and frost is generated from the ice droplets to form a frost layer ((d)). At this time, when the amount of frost formation is the same, if the size of ice droplets (or water droplets just before solidification) is large, a frost layer with large irregularities is formed, and thus the maximum value of the frost layer thickness becomes thick. Since the ventilation resistance of the heat exchanger is determined by the maximum frost layer thickness, the heat exchanger composed of untreated fins has a large ventilation resistance, and is sent to the indoor heat exchanger 25 operating as an evaporator. The air volume of the indoor heat exchanger blower 26 is reduced, and the cooling performance is likely to deteriorate.

  On the other hand, if there are pores (small pores) on the surface of the cooling surface as shown in FIG. When the pores are arranged almost evenly on the cooling surface, the water droplets are generated at substantially equal distances ((a)), so that the coalescence of the water droplets is difficult to place and small water droplets are generated ( (B), (c)). The water droplets are further cooled and solidified on the cooling surface, forming ice droplets, and frost is generated from the ice droplets to form a frost layer ((d)). At this time, when the amount of frost formation is the same, if the size of the ice droplet (or the water droplet just before solidification) is small, the frost layer becomes uneven and the maximum value of the frost layer thickness becomes thin. Since the ventilation resistance of the heat exchanger is determined by the maximum frost layer thickness, the heat exchanger composed of fins with many pores on the surface of the cooling surface has low ventilation resistance and operates as an evaporator. The amount of the indoor heat exchanger blower 26 that is blowing into the indoor heat exchanger 25 is prevented from being reduced, the cooling performance is hardly deteriorated, and energy is saved as compared with the case of no processing.

  Fig. 4 shows a photograph of water droplets immediately before solidification on an untreated cooling surface and a cooling surface having a large number of pores (an anodized cooling surface to be described later) obtained from an experiment (upper surface photograph). Indicates. The experimental conditions are air condition temperature 10 ° C, humidity 80%, cooling surface condition temperature -15 ° C, natural convection (forced air is not forced), and a photograph taken 6 minutes after the start of cooling. is there. Aluminum is used for the cooling surface. It can be seen that large water droplets are generated on the untreated cooling surface, and small water droplets are generated on the cooling surface having a large number of pores. Immediately before solidification, the size of water droplets on the untreated cooling surface is about 0.8 to 1 mm, and the size of water droplets on the cooling surface having many pores is about 0.3 to 0.5 mm. In addition, the water droplets generated on the untreated cooling surface are uneven, vary in size, have a circular shape and an elliptical shape, and have a uniform size and shape. I understand. This is because, as described above, the position of the water droplets condensed on the cooling surface is not specified, so the distance between adjacent water droplets is not a constant value, and the water droplets that happened to condense are generated near each other. Will grow and coalesce, resulting in water droplets that are not constant in size or shape. On the other hand, it can be seen that the cooling surface provided with a large number of pores has almost the same size, and has a clean circular shape. This is because, as described above, the water droplets condensed on the cooling surface can be located at the positions of the pores, so the distance between adjacent water droplets is a constant value, the coalescence of water droplets is difficult to occur, and the size is also shaped Water droplets that are constant are also generated.

  In this way, when using a cooling surface with a large number of pores with little unevenness, clean water droplets with a uniform size and shape, as well as ice droplets, can be formed, and frost with a flat and small unevenness and a thin maximum frost layer thickness. It is possible to configure a heat exchanger that generates energy, saves airflow pressure loss, reduces cooling performance, and saves energy.

  Although FIG. 4 shows the experimental results in natural convection, the size of water droplets may vary somewhat even in forced convection, but it is clear that similar results are obtained.

  When there are pores (small pores) on the surface of the cooling surface, it will be described with reference to FIGS. Air is cooled on the cooling surface (evaporator surface), becomes supersaturated air in the vicinity of the cooling surface, and becomes a mist in which minute droplets are mixed in the airflow. A part of the mist is advected by the air flow and discharged from the vicinity of the cooling surface, and the rest is condensed as water droplets on the cooling surface. At this time, where the initial water droplets (condensed droplets) are formed on the cooling surface is determined by the difference in microscopic state (fine irregularities, etc.) depending on the surface of the cooling surface, and in the case of no treatment as shown in FIG. Does not know where the initial water droplets (condensed droplets) are. Therefore, in the case of no treatment, since the position where the water droplet can be formed is not specified, water droplets are randomly generated, and the distance between the water droplets is not constant. Easy to do. On the other hand, as shown in FIG. 6, if there are pores on the cooling surface, the initial water droplets (condensed droplets) can be easily located at the ridgelines of the pores. When the size of the pore is small or not sufficiently large with respect to the size of the water droplet, a water droplet is formed on the ridge line at the top of the pore. Therefore, if a large number of pores are arranged at regular intervals on the cooling surface, and if the ridgeline to which water droplets adhere is formed even if the opening corners of the pores are rounded (R portion), Since the positions of are specified as the integral interval, a large number of uniformly small water droplets are generated in the process in which the water droplets merge and grow. In addition, as shown in FIG. 7, when the pore is sufficiently larger than the size of the water droplet or the vibration amplitude of water vapor, the moisture in the air is generated in the ridge line at the top of the pore and the inside of the pore. In this case as well, if a large number of pores are arranged at regular intervals on the cooling surface, the position of the water droplets is specified as the integral interval, so that in the process of the water droplets coalescing and growing, the uniform size is small A lot of water droplets will be generated. As will be described later, the formation of water droplets in the holes can further delay the formation of frost on the surface of the fin, which is the heat transfer surface. That is, it is smaller than making a hole such as a circle shape, an ellipse shape, or an elongated slit shape to form an opening corner where water droplets adhere to the opening, and uniformly distributing the shape of the ridge line by the opening corner. Water droplets are evenly distributed.

  However, it is necessary to generate small water droplets relative to the water droplets on the untreated cooling surface. If the distance between the pores is too far, the water droplets are condensed on the untreated cooling surface between the pores. Since it is made and a big water droplet is made, the distance between pores must be small to some extent. In an example of the anodizing process described later, the distance between the pores is about 20 nm, but the water droplets on the cooling surface having the pores in FIG. Since it is sufficient that the pores have small intervals, small water droplets can be generated up to about 0.1 mm (100 μm). However, when the size is about this size, it is sufficiently larger than the size of the water droplets that are first condensed and generated, so that water droplets are also generated between the pores and elliptical water droplets are also generated. The size of the water droplets that are initially condensed varies depending on the temperature of the cooling surface, but there is also a document describing that water droplets of about 10 nm can be formed. The distance is not sufficiently large with respect to the initial water droplet, and is most effective.

  The same can be said for the pore size (equivalent diameter or length of the shortest side), and small water droplets can be generated up to about 0.1 mm (100 μm). If the pore size is less than or equal to the size, it is not sufficiently large with respect to the initial water droplets, and is most effective.

  Here, the case where the temperature of the air is 0 ° C. or more, water droplets are formed on the cooling surface, and then solidified to become ice droplets to form a frost layer has been described. Below, the frost layer production | generation form in case the temperature of air is 0 degrees C or less is demonstrated.

  When the temperature of the air is 0 ° C. or lower, ice droplets and a frost layer are directly formed by sublimation. However, in this case as well, as described with reference to FIGS. 5 to 7, the process in which water vapor in the air is cooled on the cooling surface and mist is formed in the vicinity of the cooling surface is the same, and the mist adheres to the cooling surface. In the process, the ice droplets are formed, and the position and size of the initial ice droplets that can be formed on the cooling surface are the same as when the temperature of the air is 0 ° C. or more and water droplets are formed on the cooling surface. Also, once an ice drop is formed, the process in which the mist in the air sublimates around the ice drop and the ice drop grows is the same. When ice drops grow, the mechanism is different from coalescence of water drops, but in places where the distance between the ice drops is short, adjacent ice drops grow, and when the gap disappears, the ices combine to form one Due to the nature of clumping, they stick to each other and form large ice droplets that appear to be large ice droplets that are similar to the water droplets combined and formed into ice droplets. On the other hand, in the portion where the distance between the ice drops is long, the ice drops do not combine with each other. Therefore, on the untreated cooling surface, as in the case where the air temperature is 0 ° C. or higher, a frost layer with large irregularities is formed. The maximum value of the thickness is increased, the ventilation resistance of the heat exchanger is increased, the air volume of the indoor heat exchanger blower 26 blowing to the indoor heat exchanger 25 operating as an evaporator is reduced, and the cooling performance Tends to get worse. Even in the case where a large number of pores are provided on the cooling surface, ice droplets having the same size as when the air temperature is 0 ° C. or higher are obtained, the maximum value of the frost layer thickness is reduced, and the ventilation of the heat exchanger The resistance is reduced, and the air volume of the indoor heat exchanger blower 26 blowing to the indoor heat exchanger 25 operating as an evaporator is unlikely to decrease, cooling performance is unlikely to deteriorate, and energy is saved.

  FIG. 8 is an example of a fin tube type heat exchanger formed using fins provided with pores. The heat exchanger 40 includes fins 45 and heat transfer tubes 46, and the fins are processed so as to have a large number of uniformly distributed pores. In many cases, the fin is made of aluminum and the heat transfer tube is made of copper. For example, if the heat exchanger tube is a heat exchanger using the same aluminum as the fin material, and pores are made on both the front and back surfaces of the fin and the heat transfer tube surface, water droplet adsorption, frost layer thickness averaging, etc. More energy saving effect. In the description, an example of a fin tube type heat exchanger is given, but a heat exchanger using a flat heat transfer tube using corrugated fins may be used.

  Based on FIG. 8, a structure, a function, etc. of the heat exchanger 40 of this invention are demonstrated. Here, the fin tube type heat exchanger 40 widely used for a refrigeration apparatus, an air conditioner, etc. will be described. The heat exchanger 40 is an apparatus used as an evaporator or a condenser in the refrigeration cycle apparatus. In particular, when the heat exchanger 40 functions as an evaporator, heat exchange is performed between the low-temperature refrigerant (heat transfer medium) and the air in the target space, and the air is absorbed by the refrigerant to cool the air. The heat exchanger 40 is mainly composed of a plurality of heat exchanger fins 45 (hereinafter referred to as fins 45), a plurality of heat transfer tubes 46, and a hairpin tube (not shown) that connects the heat transfer tubes at the end of the heat exchanger. It is configured. The fins 45 of the present embodiment are flat plates (plates) made of aluminum (having a thermal conductivity of about 230 W / mK) that is easy to process, such as drilling, and that has good thermal conductivity. Further, the fin 45 has pores on the surface (both front and back surfaces) as described later. Even in the case of corrugated fins, it is effective to form pores on both sides.

  Heat transfer tubes 46 are provided so as to penetrate through holes provided in the fins 45 with respect to the plurality of fins 45 arranged at predetermined intervals. Each heat transfer tube 46 becomes a part of the refrigerant circuit in the refrigeration cycle apparatus, and the refrigerant flows inside the tube. By transferring the heat of the refrigerant flowing inside the heat transfer tube 46 and the air flowing outside through the fins 45, the heat transfer area serving as a contact surface with the air is expanded, and heat exchange between the refrigerant and the air can be performed efficiently. . A tube connecting each heat transfer tube 46 is a hairpin tube. In general, the heat transfer tube 46 and the hairpin tube are made of copper, which has high thermal conductivity and can secure strength. However, it is good also as aluminum including a heat exchanger tube etc. like an all aluminum heat exchanger. The heat transfer tubes 46 are connected by hairpin tubes to form a series of tubes. However, the piping paths of the heat transfer tubes 46 may be connected in series, for example, a plurality of heat transfer tubes penetrating the fins 45. A configuration may be adopted in which at least a part of a flow path that branches and flows the refrigerant into 46 is connected in parallel. Further, the number of through holes is not particularly limited. In addition, although the usage such as a structure where two or more heat exchangers are stacked is free, the position where the pores are provided is not limited to the fins but may be the ventilation part. It is effective for the moisture adsorption in the air to distribute the fine holes as long as the portion is affected by the temperature drop such as the air passage partition plate and the ventilation guide. For example, in the case of a flat tube heat exchanger without fins, pores are provided in the surface portion that receives the ventilation of the flat heat transfer tube.

  The heat exchanger 40 according to the present invention has pores in the heat transfer surface (in particular, the fins 45 in this case) in contact with air, and adsorbs moisture (water vapor) in the air in the environment of the target space to the pores, It also has a function for detachment. Here, when the relative pressure of water vapor is in the range of about 0.1 or more and about 0.9 or less, capillary condensation starts in the pores, so that steep adsorption / desorption of water present as water vapor in the air occurs. To occur. Among these ranges, it is considered more preferable that capillary condensation starts in a range of about 0.3 or more and about 0.8 or less, which is most likely to be applied as an environment to which the heat exchanger 40 is exposed. . Consider adsorption in a plurality of pores. In order to increase the amount of adsorption efficiently at a predetermined relative pressure (under the environment), it is preferable that there are as many pores as possible that cause capillary condensation at the relative pressure. That is, it is better that there are many pores having the same diameter. However, in forming nano-order pores, it is difficult to make all the pores have the same shape and diameter. In the present invention, if the average diameter or the short side diameter of the pores in the present invention is at most a diameter of several tens to several hundreds of nanometers, the pores with openings having ridge lines can be obtained by the anodizing method. However, when anodizing pores of the order of several hundred nm or more, μm or mm, it takes time to form the pores and the ridgeline of the opening is broken. Therefore, it is preferable to use machining such as electric discharge machining or laser machining for pores or grooves having a large diameter or width, or machining using a rotary blade for slit-like grooves. Of course, small holes with a small diameter that can be machined may be formed by machining.

  From the above, in the present invention, as an example, the processing conditions are selected so that the average diameter or the short side width diameter of the pores is formed by anodization within a range of about 2 nm to several hundred nm, and About 50% or more of pores in a predetermined range (for example, one fin 45, the entire heat exchanger 40, etc.) of the heat exchanger 40 in the environment of the target space to be dehumidified are uniformly spaced at substantially equal intervals. To distribute. It should be noted that the anodizing conditions such as the anodizing time and the relative positional relationship between the anode fin and the cathode are adjusted at the time of manufacture so that a predetermined pore diameter and pitch between the pores can be obtained. And the pore which becomes perpendicular | vertical with respect to the contact surface (heat-transfer surface) with the air in the heat exchanger 40 is formed. Thus, if the pore volume as large as possible is obtained with respect to the surface area of the fin plate constituting the fin 20 of the limited heat exchanger 10, for example, irregular pores such as an adsorbent are formed. Compared with the case where it is formed, there is no variation in the way in which the heat of the refrigerant is transmitted, and adsorption and desorption can be performed efficiently in terms of energy.

  Here, the capillary condensation phenomenon in the pores will be described. The condensation phenomenon is a phenomenon in which a part of a gas changes into a liquid when the temperature decreases. For example, in a three-dimensionally restricted space (capillary) such as the inside of a pore, gas molecules inside the pore are attracted to the pore wall rather than attracting each other due to the surface tension generated at the interface. In some cases, it is more stable, and in this case, it is known that gas molecules drawn on the pore walls easily liquefy (condense). As the gas molecules are liquefied one after another, the inside of the pores is filled with the liquid, and if the number is large, a large adsorption amount that fills the inside of the pores can be expected. Since the adsorbed liquid is in a stable state, icing is delayed and the volume is increased and the space between the fins is not reduced, which is effective for delaying frost formation. Furthermore, in a normal gas molecule adsorption phenomenon, gas molecules are strongly adsorbed by the interaction with the pore walls, so that a large desorption energy is required for desorption. On the other hand, since the molecules filled inside the pores by capillary condensation can be desorbed with relatively weak desorption energy, the input energy required for desorption can be reduced, and in particular, repeated adsorption / desorption is performed. In such a case, it has a feature that is very advantageous in terms of energy. By utilizing this capillary condensation phenomenon, it is not necessary to use an adsorbent that adsorbs moisture.

  FIG. 9 is a diagram schematically showing characteristic adsorption characteristics (desorption characteristics) obtained by the capillary condensation phenomenon as adsorption isotherms (including those related to desorption; the same applies hereinafter). The adsorption isotherm indicates the amount of adsorption during equilibrium adsorption at each pressure (concentration) under a constant temperature (isothermal) condition. In FIG. 9, the vertical axis represents a characteristic of the adsorption amount (g / g) per unit weight of the adsorbing substance (here, water molecule) (adsorption is assumed to include desorption; hereinafter simply referred to as adsorption amount). It is explanatory drawing, Comprising: A horizontal axis represents the relative partial pressure (relative pressure) when the saturated vapor pressure in the temperature is set to 1. In general, the adsorption phenomenon accompanied by capillary condensation has a hysteresis in the amount of adsorption at the time of adsorption and desorption, so that it becomes an adsorption isotherm having different characteristics at the time of adsorption and desorption. In FIG. 9, as an example, an adsorption isotherm is schematically shown in which the adsorption amount by the pores sharply increases when the relative pressure of the adsorbed material is around 0.3, and eventually becomes a plateau. This can be explained by the fact that capillary condensation begins in the relative pressure region (near 0.3) where a sharp increase in the amount of adsorption is observed, and the inside of the pores is filled with a liquid related to adsorption, resulting in a large amount of adsorption.

  In the case of pores having steep adsorption characteristics as shown in FIG. 9, the amount of adsorption increases remarkably when the relative pressure of the adsorbed substance is about 0.3 or more. Therefore, if the relative pressure in the surroundings (in the environment) is set to about 0.3 or more by some method, it is possible to adsorb the adsorbed material in a large amount and quickly into the pores. An effective way to increase the relative pressure is to lower the temperature of the surrounding environment of the adsorbing pores. For example, in the case of the heat exchanger 40, if the heat of the surrounding environment can be absorbed by the refrigerant passing through the heat transfer tube 46 and the heat transfer surface can be cooled during adsorption, the relative pressure near the pores increases. The amount of adsorption can be increased.

  Conversely, if the relative pressure is 0.3 or less, the amount of adsorption will be significantly reduced. Therefore, in this case, if the ambient relative pressure is set to 0.3 or less by some method, the adsorbed substance can be desorbed from the pores in reverse. Similarly, an effective way to reduce the relative pressure is to raise the temperature of the surrounding environment of the pores. For example, in the case of the heat exchanger 40, the amount of desorption can be increased if the pores on the heat transfer surface can be heated by releasing heat with a refrigerant or the like at the time of desorption.

  In which relative pressure region the adsorption isotherm rises sharply, that is, in which relative pressure region the capillary condensation occurs depends on the size (diameter) of the pores. For example, when the pore size is smaller than the pore having the adsorption characteristics shown in FIG. 9, capillary condensation occurs on the side of the relative pressure lower than 0.3, and the amount of adsorption begins to increase (the one-dot chain line in FIG. 9). When it becomes larger, capillary condensation occurs on the side of the relative pressure higher than 0.3, and the adsorption amount starts to increase (dotted line in FIG. 9). Generally, the relative pressure region in which capillary condensation occurs greatly affects the adsorption characteristics, but the relationship between the two can be expressed by the following Kelvin equation (1). Equation (1) shows the relationship between the two when the relative pressure (equilibrium pressure) when capillary condensation occurs is indicated by P / P0.

-------（１）

------- (1)

  Here, vl is the condensed molecular volume, γ is the surface tension, θ is the angle when contacting the capillary, R is the gas constant (8.31 [J / mol · K]), T is the absolute temperature, and r is the pore The radius is shown. This relationship also holds in the case of water vapor, and for a certain relative pressure P / P 0, the pore radius r required for water vapor to cause capillary condensation can be theoretically obtained.

  FIG. 10 is a diagram showing the relationship between the relative pressure of water vapor at 25 ° C. and the pore diameter (pore size) at which capillary condensation occurs. The horizontal axis represents the pore diameter [nm (nanometer)], and the vertical axis represents the relative pressure of water vapor at which capillary condensation occurs at 25 ° C., that is, the relative humidity at which capillary condensation occurs at 25 ° C. From FIG. 9, for example, at 25 ° C., the pore diameter at which capillary condensation occurs in an environment where the relative pressure of water vapor is 0.5 (relative humidity 50% RH) is about 3 nm (radius is about 1.5 nm). It can be seen that the pore diameter is about 9 nm (radius is about 4.5 nm) so that capillary condensation occurs in an environment of pressure 0.8 (relative humidity 80% RH). However, this is a theoretical value, and in the experiment using fins than the theoretically determined pore diameter, the shape of the pore is not a perfect circle and is not a constant value. It is desirable to aim for a large diameter during processing.

  From FIG. 10, in order to obtain a large amount of adsorption using capillary condensation that occurs inside the pores in the target environment, pores having a size such that capillary condensation occurs at the relative pressure in the environment. Many may be formed. Specifically, for example, the theoretical value is such that the average diameter of the pores is 2 nm to 40 nm or more, and the pore diameters of 50% or more are within a range of ± 20 percent around the average diameter. If distributed, sufficient capillary condensation occurs.

  Here, if the pore size is made smaller than necessary, capillary condensation occurs, but the internal volume of the pores that become the capillaries becomes smaller and the total amount of adsorption decreases. In addition, since the pore size is reduced, the interaction with the pore wall is increased, resulting in strong adsorption. As a result, large energy is required for desorption. From the above, it can be said that there is a pore size most suitable for the relative pressure of water vapor in the target environment. For example, when the pore diameter is 1 nm or less, capillary condensation may occur even in an environment where the relative pressure of water vapor is 0.1 or more. The interaction with the wall becomes stronger, and a desorption energy as large as that of zeolite is required. Therefore, in order to obtain the frosting delay, it is desirable that the thickness is about 2 nm or more from humidity, adsorption amount, desorption amount and the like.

  Thus, as can be seen from FIG. 10, the dependence on the pore size is reduced in a relative pressure region where the relative pressure of water vapor is 0.9 or more theoretically. Therefore, the pore diameters provided in the fins 45 of the heat exchanger 40 when considering the capillary condensation in the present invention are the capillaries in the range where the relative pressure of water vapor is 0.3 or more (relative humidity is 30% RH). The diameter at which condensation occurs is desirable. However, as described with reference to FIGS. 3 to 7, when the water droplets are evenly distributed, the size of the pores (equivalent diameter or length of the shortest side) is smaller than the size of the water droplets from which small water droplets are obtained. Small water droplets can be generated up to about 0.1 mm (100 μm). On the other hand, the water molecules adsorbed in the pores have the Gibbs-Thomson effect that the melting point is lowered, and if the pore size is about 100 nm or less in diameter, the melting point is lowered at least 1 degree or more. This is because the moisture that is the adsorbed liquid is in a stable state in the limited space, the melting point is lowered, and even if the cooling temperature of the evaporator is low, it is difficult to freeze and the start of freezing is delayed. If the pore diameter is reduced, for example, the melting point becomes −40 ° C. at about 2 nm, and the decrease in the melting point becomes about the number of commas at a diameter of the order of μm. If the melting point is lowered, the formation of ice crystals can be delayed, which is effective for delaying frost formation. Therefore, it can be said that the delay effect is further increased in the case of a pore size of about 100 nm or less in diameter. In order to obtain small water droplets for suppressing the thickness of frost, the pores are uniformly distributed, and the pore diameter is about 0.1 mm (100 μm) or less, and the frost formation delay effect is obtained at about 2 nm or more. Moreover, by increasing the diameter, not only the fin surface area is increased and the heat transfer performance is improved, but more moisture can be adsorbed and the effect of delaying frost formation is great. However, if the pore size is about 100 nm or less and 2 nm or more, a significant effect on frosting delay can be obtained by the effect of lowering the melting point of moisture in the pores.

  In addition, since the relative pressure of water vapor that causes capillary condensation varies depending on the pore size, for example, when pores having various sizes are mixed on the same heat transfer surface, it is excellent in humidity and temperature conditions in a specific environment. However, the pores having a size to obtain the adsorption performance are reduced, but the adsorption ability in various environments can be shown. On the other hand, when 50% or more of the pores provided in the heat exchanger 40 have a size within a range of ± 20 percent centering on the average diameter, it is excellent in humidity and temperature conditions in a specific environment. Adsorption performance can be obtained. If the pore diameter set in this way is set, as shown in FIG. 7, in the case of a hole sufficiently large with respect to the size of the water droplet, even if the effect of lowering the melting point is small, there is no water droplet inside the pore. When condensed and viewed from the whole fin, it is the same as the state in which the surface area for condensing water droplets and storing moisture is increased, and the effect of suppressing the thickness of frost can be obtained. Further development of these ideas to increase the pore diameter close to the surface and reduce the pore diameter in the deep part of the pore, and the structure in which the diameter in the depth direction of the pore is changed stepwise, the use conditions of the heat exchanger Depending on the case, a better frosting delay effect can be obtained. In this case, the opening ridgeline to which the droplet is attached can be provided in a wide pore on the surface or a narrow narrow hole in the deep portion or both.

  Next, the depth of the pores will be described. The amount of water vapor that can be adsorbed in the pores by capillary condensation also depends on the depth of the pores. Therefore, the depth of the pores provided in the heat exchanger 40 of the present invention is preferably in the range of 1 μm to 1000 μm (1 mm). For example, if the depth of the pores is 1 μm or less, the absolute volume of the volume capable of holding the liquid (water) condensed and adsorbed by the capillary is insufficient. Moreover, since the number of adsorption / desorption increases, it is not efficient. On the other hand, a pore depth of 1000 μm or more has a depth / diameter ratio of about 1000000 times or more with respect to the pore diameter in nano order. Therefore, it takes a long time to allow water molecules to reach the bottom of the pores during adsorption and to discharge water molecules from the openings during desorption. For this reason, when considering the pore formation processing time and the like, it is considered that forming between 10 μm and 200 μm (more specifically, around 100 μm) is preferable from the viewpoint of processing and securing the moisture adsorption amount.

  Moreover, it is good that all the structural members of the heat exchanger 40 are aluminum. All the components including the heat transfer tubes and fins 45 are made of aluminum having good thermal conductivity, so that not only heat transfer from the heat exchanger 40 to the pores is performed smoothly, but also current and time are reduced. By performing the anodizing treatment to be described later, a large number of pores having the same diameter can be formed in a relatively uniform distribution, and pores having a uniform pore diameter can be easily obtained.

  Further, the step of removing surface oxides by acid treatment on the fins 45 before assembling the heat exchanger 40, the anodizing step using the fins 45 as an anode, and the sealing of the fins 45 that have been anodized are prevented. For example, the heat exchanger 40 may be assembled by immediately performing a heat treatment step for forming the pores on both sides of the fins 45 and then expanding the heat transfer tubes 46 through the through holes of the fins 45. By performing this heat treatment step, it is possible to maintain the state in which the opening corners of the pore openings are formed, and it is possible to attach droplets without breaking the narrow hole opening ridge line.

  Here, the anodic oxidation treatment of the present invention that can form pores of several hundred nanometers or less at low cost and uniformly with good control will be described. This surface treatment method called anodization is a conventional alumite treatment method, which generally improves the corrosion resistance by sealing the open holes. In the present invention, the ridgeline is maintained immediately after the open holes are opened. The process which performs is performed. For micro-order and millimeter-order pores, machining, electric discharge machining, laser machining, etc. that can secure a ridgeline to which droplets adhere even if the corners of the opening are rounded are desirable.

  The anodizing method is a method in which direct current electrolysis is performed in an electrolyte solution (hereinafter referred to as an electrolytic solution) using a metal to be treated as an anode and an insoluble electrode as a cathode. By energizing between the anode and the cathode, the surface of the metal as the anode is oxidized, and a part of the metal is ionized and dissolved in the electrolytic solution. The metal ions react with water in the electrolytic solution to generate a metal oxide. The form of the metal surface obtained by the anodizing treatment varies depending on the electronic conductivity of the metal oxide. In particular, any metal such as aluminum, niobium, and tantalum that has an electrolytic rectifying action, which is a valve action that causes a current to flow only in one direction and not to flow in the reverse direction, is formed by a thick and dense oxide film on the metal surface by anodizing treatment. In other words, a so-called valve metal capable of forming a porous film is used. Since an oxide film formed on a fin or the like using this metal has poor electron conductivity, a metal oxide (anodized film; alumina in the case of aluminum) grows on the base metal as anodization proceeds. At this time, a grown pore structure can be formed by selecting an appropriate electrolyte solution (hereinafter referred to as an electrolytic solution) and current and / or voltage conditions.

  FIG. 11 is a schematic diagram of a theoretical regular pore cross-sectional structure formed by anodizing. By the anodizing treatment, a porous layer that is an anodized film is formed on the surface. This anodic oxide film, which is a porous layer, grows perpendicularly to the base metal 45, and consists of a porous portion in which pores are formed and a barrier layer portion in contact with the metal, and has a hexagonal cell pore structure. ing. The anodized film is composed of a porous layer in which vertical pores are formed and a barrier layer in the bottom wall portion in contact with the base metal, and has a so-called hexagonal cell structure. The above is a basic explanation based on the schematic diagram. In actual manufacturing, the energized state is not constant, and the surface becomes irregularly shaped pores for the sake of taking time. Many parameters need to be controlled so that a number of holes having a preselected hole diameter, pitch and depth are formed. When forming the pores, the thickness of the barrier layer is basically formed constant, so that the depth control of the pores is performed by substantially controlling the thickness of the film. Since the film formation speed and thickness depend on the current or potential between the two electrodes to be supplied and the anodizing time, the current or potential between the two electrodes to be supplied and the anodizing time are controlled when forming pores of a predetermined depth. To do. Further, since the number of pores (density) per unit area and the pore diameter depend on the potential between the two electrodes, the potential between the two electrodes is controlled in order to form the predetermined number and the pore diameter. Therefore, when the hole diameter is changed during drilling, the voltage may be changed. Further, a mold (mold or the like) in which protrusions are formed in accordance with the interval between the pores is pressed against the aluminum surface to be a fin to form regular depressions on the surface. Thereafter, when anodization is performed, pores are formed around the recessed portion, the pores can be arranged in a fairly regular order, and high control can be performed in terms of density. More importantly, in order to prevent pores formed by anodization from reacting with moisture in the air and blocking them, the fins 45 are heated with hot air of about 100 to 200 ° C. immediately after the pores are formed. The operation of removing moisture contained in the film and changing to a stable oxide is performed. A heat exchanger is formed by passing heat transfer tubes through the through holes of the plurality of fins formed as described above.

In forming the pores on both sides of the fin plate to be the fin 45 by anodic oxidation, the pore diameter, the number of pores per unit area and the pore diameter are empirically proportional to the voltage and / or current between the electrodes. It is known. As an example, Electrochemical Handbook 5th Edition (Electrical Society of Japan, Maruzen) p. 449 to 453 show the relationship between the diameter 2r [nm] of the pores and the voltage Ea [V] between the electrodes, as shown by the following equation (2).
When voltage Ea <15V, 2r = 13.9 + 0.21 × Ea
When voltage Ea> 15V, 2r = 4.2 + 0.84 × Ea (2)

  This equation (2) is an empirical equation and is not necessarily applicable to all anodizing treatments. Moreover, it is difficult to generalize the conditions for determining the pore diameter because it is affected by the surface state of the metal to be anodized, the type and concentration of the electrolyte used in the anodizing treatment, the liquid temperature, and the like. However, it is shown that the control for forming the selected pore diameter is possible by controlling the current and voltage between the electrodes in the anodizing treatment.

  On the other hand, the depth of the pores can also be controlled by appropriately setting the conditions in the anodizing treatment. When the anodic oxide film has poor electron conductivity, such as aluminum, the electric field that is the driving force for anodic oxidation is applied to the barrier layer with higher electron conductivity, and the thickness of the barrier layer portion is constant. Go. Then, oxidation proceeds only at the boundary between the porous portion and the barrier layer portion, that is, at the bottom of the porous layer, and an anodic oxide film grows. As a result, the thickness, which is the depth of the pores, increases with the time of anodizing treatment or the amount of applied current (the amount of coulomb applied to the film). By increasing the anodic oxidation time or the applied current in this manner, for example, the through holes can be formed in the fin 45 by performing an anodic oxidation treatment from both sides of the thinned fin plate. In a hole with a small hole diameter, a large amount of energy is required to freeze the water. The smaller the hole, the more the water is supercooled and the more the ice is frozen. Delayed, the defrosting interval can be lengthened, saving energy. The deeper the depth of the pores, the greater the amount of water retained in the pores, so that the frosting delay effect and the energy saving effect are further increased. When the depth of the pores is, for example, 10 μm or more, a sufficient water retention amount is obtained, and the energy saving effect is large.

  In order to obtain the desired pore size and pore depth most suitable for the relative pressure of the water vapor to be adsorbed by the above-mentioned anodizing treatment, the pore current can be changed by changing the current or voltage of the anodizing treatment. The diameter of the pores can be controlled by changing the diameter size or the amount of current flowing between the electrodes (which changes the amount of coulomb (current × time)).

As described above, as a method of attaching pores to the cooling surface (fin) surface, for example, there is a method by anodization (anodization). Anodization (anodic oxidation) can form pores on the fin surface simultaneously on both sides. In an environment where fin (aluminum) is used as an anode, in an acidic solution such as sulfuric acid, oxalic acid, phosphoric acid, or chromic acid, in a neutral solution such as ammonium borate, or in an alkaline solution such as sodium hydroxide or sodium phosphate When direct current electrolysis is performed, for example, aluminum ions (Al ₃ ⁺ ) dissolved from fins (aluminum) react with water (H ₂ O), and the aluminum oxide (alumina) film (anodic oxide film) is a base metal. Produced on some aluminum. Here, in order to accurately form nano-order sized pores suitable for moisture adsorption / desorption when using capillary condensation, it is desirable to use an acidic aqueous solution as an electrolytic solution for anodization treatment, particularly with strong acid. Some sulfuric acid and hydrochloric acid are desirable.

  In addition, nano-order pores formed by anodization treatment are altered by an air vapor in the air and ambient temperature, etc., so that the pores are not sealed (do not block). Immediately after formation, it is important to stabilize the pore structure by removing the water by heat treatment at 100 ° C. or higher (more preferably about 150 ° C. or higher), which is the evaporation temperature of water.

  Next, the theoretical need for pores to allow capillary condensation to occur and sufficient moisture adsorption to occur, depending on the relative pressure of water vapor in a particular environment to which the heat exchanger 40 is exposed. The conditions will be described.

  There are various places where the heat exchanger 40 is used, that is, a refrigeration apparatus for controlling temperature and humidity by a refrigeration cycle is used. For example, it is known that the relative pressure of water vapor at 25 ° C. is generally 0.3 to 0.6 in a living space where people are generally active. In recent years, the Building Management Law has been enacted, and temperature: 17-28 ° C., relative humidity: 40-70% RH (relative pressure of water vapor: 0.4-0.7) has been set as a standard. The importance of temperature and humidity management is increasing. Also, in factories that handle food processing, from the viewpoint of HACCP (Hazard Analysis and Critical Control Point) management, low temperature and low humidity (for example, 5 ° C, 30% RH or less, etc.) according to food for antifungal and fungicidal measures The management value is set. Furthermore, in the art museums and museums, the temperature in the exhibition room is 20 to 22 in order to suppress the expansion / contraction of the exhibits due to a rapid temperature change and the activity of mold that rapidly increases when the humidity environment exceeds 60% RH. In many cases, the temperature and the relative humidity are set to be constant values of 50% to 55%.

  Thus, since the heat exchanger 40 is used in various temperature and humidity conditions in the external environment, pores are provided on the heat transfer surface of the heat exchanger 40, and water vapor is generated by capillary condensation in the pores. For adsorbing and desorbing, it is convenient to select pores of a size corresponding to each use environment or smaller based on FIG. However, in practice, a larger hole diameter than the theory is better.

  For example, consider a case where the heat exchanger 40 of an air conditioner located in a living space is exposed to an environment of 0.5 (relative humidity 50% RH), which is the relative pressure range. In order for capillary condensation to occur in the pores of the heat exchanger 40, a pore size having a pore radius of about 1.5 nm, that is, a pore diameter of about 3.0 nm is desirable from the equation (1). Also, in a space where a low humidity environment of 30% RH or less is required such as in a food processing plant, the pore radius is about 1.0 nm, that is, the pore diameter is about 2.0 nm or less from the equation (1). A pore size is required.

  Further, the total adsorption amount that can be adsorbed varies greatly depending on the humidity region in which the heat exchanger 40 is used. For example, in the case of a living space where people are active, it is estimated that a dehumidifying effect can be obtained if water vapor can be adsorbed at a rate of about 100 to 200 g (water vapor) / h. That is, in order to realize dehumidification by capillary condensation, it is only necessary to adsorb about 100 to 200 g (water vapor) of water vapor from the air in one pass. Here, the total adsorption amount of the entire moisture (water vapor) is also determined by the depth of the pores. For example, when considering a 1 hp chiller, the surface area of the fins 45 of the heat exchanger 40 used in the chiller Is about 4 m 2. For example, for pores having a size of about 3.0 nm, a pore depth of about 25 to 50 μm is sufficient to adsorb such an amount of moisture (water vapor) in one pass.

  The type of the heat exchanger of the present invention is not limited to the above description. For example, a corrugated fin is provided with a fine hole instead of a fin on a flat plate, or a flat heat transfer tube is used and no fin is provided. A heat exchanger with improved heat transfer performance may be used. In this case, a large number of pores are treated on the outer surface of the heat transfer tube. This type of heat exchanger is often made of aluminum.

  In terms of the strength of the heat exchanger, it is preferable to provide the pores so as not to penetrate the fin surface. However, when the pore pitch is significantly larger than the pore diameter or the pore location is limited to a specific location on the fin. In such a case, it may be a fine hole penetrating the fin, and the effect of generating small water droplets remains the same. In the present invention, moisture in the air can be stored in the pores described above, and the growth of frost can be delayed to form a thin frost layer, so that the performance deterioration during operation of the apparatus can be suppressed. Further, by extending the defrost cycle, useless energy such as defrosting can be reduced to provide an energy saving device.

Embodiment 2. FIG.
In the second embodiment, pores satisfying the pore selection conditions (for example, pore diameter 3.0 nm, pore depth 50 μm) are formed on the fin plate, and the heat described in FIG. A method of forming the fins 45 of the exchanger 40, a configuration of the heat exchanger 40 obtained by expanding the heat transfer tubes 46 through the through holes of the fins 45 having pores, a manufacturing method, and the like will be described.

  First, before the anode joining treatment, a pure aluminum rolled sheet (eg, JIS1060 grade, thickness 200 μm) as a raw material is cut into a size to be a fin 45, and a through hole for passing the heat transfer tube 46 and a predetermined cut and raised process are performed. A flat fin plate to be the fin 45 is produced. Depending on the size and capacity of the heat exchanger 40, several hundreds of fin plates are usually required for one heat exchanger 40. Next, an example of a process flowchart of processing steps related to pore formation in the fin plate shown in FIG. 12 will be described.

  In FIG. 12, for the purpose of removing organic contaminants present on the surface of the fin plate aluminum, the fin plate is dipped (immersed) in a commercially available degreasing solution heated to 50 ° C., for example, for 2 minutes to perform a degreasing process (S1). . Then, the water washing process by ion exchange water is performed (S2). Subsequently, in order to remove the natural oxide film formed on the surface of the fin plate, in an alkaline etching solution heated to about 60 ° C. (for example, a NaOH (sodium hydroxide) aqueous solution having a concentration of 1 M (mol / l)). Then, an alkali etching (wet etching) process is performed by dipping for 1 minute (S3). Then, the water washing process by ion-exchange water is performed (S4). Next, in order to remove the reactants (impurities and smuts) generated on the surface by wet etching (desmut), it is immersed for 30 seconds in a desmut solution (0.5M-H2SO4 (sulfuric acid) solution) controlled at room temperature, and desmut treatment (S5). Thereafter, a water washing process with ion-exchanged water is similarly performed (S6).

  FIG. 13 is a principle diagram mainly showing an apparatus related to anodization. In FIG. 13, the electrolytic solution 62 of a 1M-H 2 SO 4 aqueous solution fills the inside of the electrolytic bath (water bath) 63. After controlling the bath temperature to 10 ° C. by the electrolytic bath 63, it is connected to the DC power source 61, and the one fin plate 65 to which voltage is applied is used as an anode, and the two planar carbon plates 64 are used as cathodes. It was immersed in the electrolytic solution 62. Then, anodization is performed while controlling the constant current so that a constant current of 1.5 A / dm2 flows between both electrodes (S7). Here, in order to maintain the surface state in the initial stage of the reaction, it is assumed that anodization is started by hot start (a voltage is applied between both electrodes in advance and a current flows at the same time as being immersed in the electrolyte). The anodizing time is 30 minutes. Since the carbon plate 64 is processed in such a manner that the fin plate 65 is in the center and the respective flat portions of the fin plate 65 are opposed to each other, anodization proceeds on both surfaces of the fin plate 65 simultaneously.

  Here, as described above, it is desirable that the pores to be formed are uniformly distributed and the diameters of the pores are as many as possible (uniform). For this purpose, measures such as making the current density of the entire fin plate 65 uniform are taken. For this reason, for example, the size of the carbon plate 64 serving as the cathode is made equal to or larger than that of the fin plate 65, the vibration of the electrolytic solution 62 is suppressed, and the like, so that metal ions are deposited and reacted uniformly. Further, since both surfaces of the fin plate 65 are anodized under the same conditions, the intervals between the fin plate 65 and the two carbon plates 64 are made the same. In some cases, an auxiliary electrode is used so that the whole is anodized under the same conditions according to the shape.

  As the anodization proceeds, an oxide (anodized film) grows on the surface of the fin plate 65, and the interface resistance increases. As described above, since the constant current control is performed in the anodic oxidation process, the voltage between both electrodes gradually increases.

  When the anodizing process is completed, the fin plate 65 is immediately pulled up from the electrolytic solution 62 and washed with ion-exchanged water (S8). After water droplets adhering to the fin plate surface are blown off with a blower, they are immediately put into an oven (in the atmosphere) that has been heated in advance in order to reinforce the shape structure of the pores formed by anodization. Here, the temperature in the oven is about 150 ° C. And it heat-processes for 60 minutes, takes out from oven, and cools slowly (S9). For example, 120 fin plates 65 are prepared as fins 45 in which pores are formed in the heat transfer surface by such a method.

  FIG. 14 is a diagram showing an adsorption isotherm in the fin 45 manufactured in the processing step of FIG. Here, the moisture adsorption characteristics and pore size distribution of the pores formed in the manufactured fin 45 are evaluated by equilibrium adsorption measurement.

  First, for example, a part of the same fin plate as the fin 45 is cut into an appropriate size and packed in a sample tube, pretreated in a vacuum of 150 ° C. × 1 h, and then an automatic gas / vapor adsorption amount measurement is performed. The moisture adsorption isotherm at 25 ° C. was measured using the apparatus. From FIG. 14, although there is hysteresis between adsorption and desorption, the average of adsorption / desorption shows a steep rise (fall) when the relative pressure P / P0 is around 0.5. It can be seen that adsorption / desorption by capillary condensation is performed. In addition, the amount of moisture adsorbed at this time is about 200 g per pore unit weight, indicating that sufficient adsorption characteristics are exhibited. The depth of the formed pores was about 50 μm.

  FIG. 15 is a graph showing the pore size distribution, and the pore size of a sample exhibiting capillary condensation when the relative pressure is around 0.5 is obtained by the BJH (Barrett-Joyner-Halenda) method. From FIG. 14, the pore size distribution reaches a maximum around 3.5 nm, and a steep pore distribution peak is obtained. Therefore, 50% or more of the pores have a pore diameter of 3.5 nm ± 2 nm. It can be confirmed that it is included in the range. In other words, pores of approximately the same size as the selected pore diameter of 3.0 nm and pore depth of 50 μm were obtained.

  Subsequently, a plurality of copper heat transfer tubes in which refrigerant flows through the through holes of the fins 45 arranged in two rows and three rows and stacked in the same direction, for example, with 120 fins 45 having such adsorption characteristics. 46 is inserted. Further, a jig is inserted into the heat transfer tube 46 and expanded from the inside so that both the fin 45 and the heat transfer tube 46 are integrated. At this time, it is assumed that the fins 45 arranged at regular intervals. Further, in order to connect a plurality of heat transfer tubes 46 in series (in a series), a hairpin tube formed by bending a copper tube into a hairpin shape (bending) is prepared, and the heat transfer tube 46 is filled with nitrogen gas. After that, the end of the two heat transfer tubes to be connected and the hairpin tube are brazed. As described above, a heat exchanger 40 as shown in FIG. 8 is obtained.

  As described above, a plurality of pores are formed on the surface of the fin plate that constitutes the fin 45 serving as the heat transfer surface of the heat exchanger 40, and the fin 45 itself functions as a means for adsorbing moisture. For example, moisture can be adsorbed from the air passing between the fins 45 without requiring special means such as a powdery adsorbent such as silica gel. Thereby, the frost formation to the heat exchanger 40 including the fin 45 can be prevented, and the frequency | count, time, etc. of a defrost operation can be reduced. In addition, the adsorbent can be prevented from peeling off, and it is safe and easy to manage from the viewpoint of hygiene. And there is no thermal resistance between the fin 45 and the adsorbent, and the heat transfer effect is not impaired. Adsorption material does not reduce the space between the fins 45 of the heat exchanger 40, improves the air flow between the fins 45, and further increases the surface area on the heat transfer surface due to the irregularities due to the pores. Furthermore, it can be performed efficiently. In addition, since there is no air pressure loss due to the adsorbent, heat exchange can be performed efficiently from the viewpoint of energy and the like. In addition, since the adsorbent need not be provided, the entire heat exchanger 40 with good performance can be made compact.

  And, when the relative pressure of water vapor is about 0.3 or more, the average diameter of the pores is about 2 nm or more so that moisture can be adsorbed and desorbed. Since the diameter is distributed within a range of about ± 20 percent from the average diameter, and the pores are formed so as to form a depth according to the desired adsorption amount, The heat exchanger 40 (fin 45) with high adsorption capability can be obtained in the vicinity of the lower relative pressure.

  In particular, in order to produce pores having a specific diameter, for example, capillary condensation is caused to occur in accordance with the relative pressure environment of water vapor to which the heat exchanger 40 in an air conditioner located in a living space is exposed. Therefore, the anodizing treatment is performed by immersing in an anodizing electrolyte of 1M-H2SO4 aqueous solution. For example, in each fin 45 (heat exchanger 40), the diameter of about 50% of pores is about 3.5 nm ± 20 percent. By forming pores that fall within the range, forming deep pores that match the amount of adsorption, and cooling the pores directly with a refrigerant with high thermal efficiency, the relative pressure of 0. In the vicinity of 5, the heat exchanger 40 with improved adsorption characteristics can be obtained. 14 also has a desorption characteristic as shown in FIG. 14, so that a high-temperature refrigerant can be passed through the heat transfer tube 46 at the time of desorption, and the pores directly formed in the fins 45 can be directly heated. The relative pressure can be increased, the water vapor adsorbed in the pores can be efficiently desorbed, and the heat exchanger 40 having excellent heat transfer efficiency and energy saving can be obtained.

  On the other hand, from a hygienic point of view, factories that handle food processing usually have a control value of lower temperature and lower humidity (for example, 5 ° C-20% RH, etc.) than normal environments to prevent mold and prevent bacteria. Is set. Therefore, an example in which the most suitable heat exchanger 40 is manufactured in such a low temperature / low humidity environment will be described below.

  When the heat exchanger 10 having pores is exposed to an environment where the relative pressure of water vapor is about 0.3 (relative humidity 30% RH), the pore radius is about 1.0 nm, that is, about 2.0 nm. It is expected that the most excellent adsorption characteristics can be obtained in pores having a pore diameter. Further, in a low temperature and low humidity environment, the absolute amount of moisture in the air is not so large, so it is considered that it is sufficient that moisture can be adsorbed at a rate of about 50 to 100 g (water vapor) / h. From the above, in such an environment, the depth of the pore is predicted to be about 50 to 75 μm.

  Based on the above prediction and the like, pore formation was performed on the fin plate by the process shown in FIG. However, in this example, as will be described later, the conditions for anodizing are different. First, degreasing → alkali etching → desmut treatment (S1 to S6 in FIG. 12) is performed under the same conditions and solution as described above.

  Next, anodizing treatment was performed using the electrolytic cell 63 shown in FIG. 13 (S7 in FIG. 12). A 0.5M-H2SO4 aqueous solution in which the bath temperature is controlled at 20 ° C. is used as the electrolyte. Then, one fin plate is used as an anode, two carbon plates are used as a cathode and immersed in an electrolytic solution, and a constant current is controlled so that a constant current of, for example, 2.0 A / dm2 flows between both electrodes. I do. Here, the anodizing time is 45 minutes.

  When the anodizing treatment is completed, the anodizing treatment is taken out of the electrolytic solution, washed with ion exchange water and drained by a blower. Then, in the same manner as described above, it was immediately put in an oven (in the atmosphere) heated to 150 ° C., and as it was, heat treatment was performed for 60 minutes, taken out from the oven, and gradually cooled (S8 to S9 in FIG. 12). For example, 200 fins 45 having pores formed on the heat transfer surface by such a method are prepared.

  FIG. 16 is a diagram illustrating an adsorption isotherm in the created fin 45. Since the pretreatment conditions, the evaluation apparatus, and the measurement method are the same apparatus and method as the previous adsorption characteristic evaluation, the description thereof is omitted. In FIG. 16, although there is hysteresis between adsorption and desorption, a steep rise (fall) is observed when the relative pressure P / P0 is around 0.3 in the average of adsorption / desorption. In addition, the amount of moisture adsorbed at this time is about 70 g per unit weight of the pores, indicating that sufficient adsorption characteristics are exhibited. The depth of the formed pores was about 70 μm.

  FIG. 17 is a diagram showing the pore size distribution, and the pore size of a sample exhibiting capillary condensation when the relative pressure is around 0.3 is obtained by the BJH method. From FIG. 17, the pore size distribution reaches a maximum at around 1.8 nm, and a steep pore distribution peak is obtained, so that 50% or more of the pores have a pore diameter of 1.8 nm ± 2 nm. It can be confirmed that it is included in the range of 2 nm, and a pore having a selected pore size of about 2 nm is obtained.

  Next, 300 fins 45 having the above-mentioned adsorption characteristics were arranged in three rows and four rows, and the heat exchanger 40 having pores on the heat transfer surface was manufactured by the same method.

  As described above, so as to obtain a heat exchanger 40 suitable for a low temperature and low humidity environment such as a factory that handles food processing, it is immersed in an anodizing electrolyte solution of 0.5M-H2SO4 aqueous solution and anodized. For example, in each fin 45 (heat exchanger 40), pores having a diameter of about 50% within a range of about 1.8 nm ± 2 nm are formed, and pores matched to the amount of adsorption are formed. The pores can be formed and directly cooled with a refrigerant efficiently.

  The heat exchanger 40 in the following example is the same as the above-described embodiments in configuration. However, similarly to the fin 45, the heat transfer tube 46 (including the hairpin tube) is made of all-aluminum, using aluminum that has good thermal conductivity and can be anodized as a material. In addition to the fins 45, pores are formed not only in the heat transfer tubes 46 (including hairpin tubes).

  The assembly of the heat exchanger 40 is the same as the method described in the present embodiment. For example, 160 fins 45 are arranged in three rows and four rows, and the heat transfer tubes 46 are inserted into the through holes of the fins 45. . And the heat exchanger tube 46 is expanded from the inside, and it forms so that both the fin 45 and the heat exchanger tube 46 may be integrated. Further, the plurality of heat transfer tubes 46 are connected by hairpin tubes. Thereby, the heat exchanger 40 made of all aluminum is prepared.

  The openings at both ends of the heat transfer tube 30 for pipe connection with other equipment of the refrigeration cycle apparatus are masked with a fluororesin tape made of, for example, PTFE (polytetrafluoroethylene) and transferred to the electrolyte solution when immersed. Processing is performed so that the electrolytic solution does not enter the tube from the end of the heat tube 46. For this reason, it is possible to prevent the inside of the tube from being anodized and to increase the flow path resistance of the refrigerant by, for example, an anodic oxide film. Thereafter, the pores are formed in the heat exchanger 40 in the process flow shown in FIG. First, degreasing → alkali etching → desmut treatment (S1 to S6 in FIG. 12) is performed under the same conditions and solution as in the first embodiment.

Anodization as shown in FIG. 13 is performed using the entire heat exchanger 40 as an anode instead of the plate. Therefore, the heat exchanger 40 as a whole becomes an anode, but a plurality of electrodes are attached at positions symmetrical with respect to the center line of the heat exchanger 40 in order to reduce variation in current density. On the other hand, for the cathode, a flat carbon plate is used as in the first embodiment. However, at this time, four carbon plates were used to surround the heat exchanger 40.

  In this embodiment, the heat exchanger 40 and the carbon plate 64 are immersed in the electrolytic solution 62, and processing is performed under constant current control so that a constant current of 2.0 A / dm2 flows between both electrodes. The anodizing time here is 20 minutes.

  When the anodizing treatment is completed, the heat exchanger 40 is pulled up from the electrolytic solution and washed with ion-exchanged water and blower drained as in the first embodiment. Then, immediately put in an oven (in the atmosphere) heated to 150 ° C., heat treatment is performed for 60 minutes as it is, take out from the oven and gradually cool (S8 to S9 in FIG. 12). The pores are formed by such a method, and the heat exchanger 40 having pores as a whole is manufactured.

  Although the surface of the entire heat exchanger 40 is anodized after the assembly is completed, the heat transfer tubes 46 and the fins 45 are all made of aluminum, and not only on the surfaces of the fins 45 but also on the surfaces of the heat transfer tubes 46. Pores are also formed. Therefore, it is advantageous because the number of pores increases and the area in contact with the air in the target space containing water vapor increases.

  FIG. 18 is a diagram illustrating an adsorption isotherm in the heat exchanger 10 in which pores are provided on the entire outer surface of the heat exchanger. Since the pretreatment conditions, the evaluation apparatus, and the measurement method are the same as those in the case of the adsorption characteristic evaluation performed in the first embodiment, the description thereof is omitted. From FIG. 18, although there is hysteresis between adsorption and desorption, the average of adsorption / desorption shows a steep rise (fall) when the relative pressure P / P0 is around 0.40. In addition, the amount of water adsorbed at this time is about 120 g per unit weight of the pores, indicating that sufficient adsorption characteristics are exhibited. The depth of the formed pores was about 180 μm.

  FIG. 19 is a diagram showing the distribution of pore sizes. The pore size of a sample exhibiting capillary condensation when the relative pressure is around 0.4 is determined by the BJH method. From the figure, the pore size distribution reaches a maximum at around 2.5 nm, and a steep pore distribution peak is obtained. The aperture distribution was observed.

  As described above, not only the fins 45 but also the heat transfer tubes 46 and the hairpin tubes are made of aluminum, and the heat transfer tubes 46 (and the hairpin tubes) are also formed with pores. The area (number of pores) of the portion having pores capable of adsorbing and desorbing can be increased, and a larger amount of moisture can be adsorbed without depending on the adjustment of the depth of the pores.

  Next, a 1M-NaOH aqueous solution exhibiting strong alkalinity is used as the electrolyte in the anodizing treatment, and the anodizing treatment is performed for 40 minutes under constant current control so that a constant current of 3 A / dm @ 2 flows. Other than that, pore formation was performed under the same conditions / method as in the first embodiment. It should be noted that white powder was blown on the surface of the fin 45 after the anodizing treatment.

  FIG. 20 is a diagram illustrating an adsorption isotherm in the created fin 45. Since the pretreatment conditions, the evaluation apparatus, and the measurement method are the same as those in the case of the adsorption characteristic evaluation performed in the first embodiment, the description thereof is omitted. As shown in FIG. 20, there is hysteresis between adsorption and desorption, but the adsorption amount does not rise sharply (decrease) in both adsorption and desorption, and gently adsorbs as the relative pressure increases (decreases). The amount (desorption amount) of the isotherm increased (decreased).

  FIG. 21 is a view showing the pore size distribution, which is obtained by the BJH method. From FIG. 21, the pores are large as a whole, and the distribution is maximized around 10 to 11 nm. On the other hand, a lot of fine pores of 7 nm or less were also found, and the pore distribution as a whole had bimodal peaks (two peaks). This is because a strong alkaline aqueous solution is used as the electrolyte, so that the dissolution of the metal preferentially proceeds over the pore wall oxidation growth (growth of the anodic oxide film), the pore diameter becomes large, and the pores The distribution is also thought to have widened. However, the ridgeline of the opening is seen and the distributed size is small. According to the method of manufacturing the heat exchanger 40, if the time is not excessively long, the droplets are reduced. In this way, a product with a uniform distribution is obtained, and narrow holes with different opening sizes are included, but a uniform distribution is obtained.

  In the above description, the fin material is described as being aluminum, but the material is not limited to aluminum. For example, so-called valve metal (valve metal) may be used as a material for the fin, and pores may be formed on the surface by anodic oxidation. The valve metal is a generic term for metals such as aluminum, tantalum, niobium, titanium, hafnium, zirconium, zinc, tungsten, bismuth, and antimony that can form an oxide film that exhibits an electrolytic rectifying action by an anodic oxidation method. Among these, metals that can be used practically as fins are, for example, aluminum, titanium, zirconium, niobium, and tantalum. Even if these metals are used, the same effect as aluminum can be obtained.

  By using the anodization method, just immerse the fin material of a heat exchanger such as aluminum in a solution and apply an electric field to create pores on both sides of a large number of fin materials at once. Can be manufactured at low cost. In addition, the anodizing treatment may be performed in the production line, but the time for immersing the fin material in the acidic solution is, for example, about 5 to 30 minutes, and the anodized fin material is purchased with a roll. In addition, it is cheaper to cut and use the heat exchanger when it is manufactured. With reference to FIG. 22, an example of pores manufactured by anodizing a 88 mm * 203.2 mm size fin will be described. In FIG. 22, (A) shows pores obtained with a processing time of 5 minutes, (B) shows processing time of 30 minutes, and (C) shows processing time of 90 minutes. Each example is enlarged 500,000 times, and the depth of each hole is several μ to several tens of micro. Although each example looks like an irregular mesh shape, it is shown that nm-order holes indicated by black spots are uniformly distributed on the fin surface, and the hole pitch is formed to the same degree. Yes. Experimentally, if the anodizing time is short, there is a problem that the depth of the hole becomes shallow, and it is preferable that 10 minutes or more, and it is confirmed that a good ridge line can be obtained even if the processing time is 90 minutes. . As shown in FIG. 22, the ridge lines based on the holes are uniformly formed at the same pitch, and as a result, the water surface has a large number of pores on the surface described in FIG. A simple water droplet distribution, and thus a thin frost distribution.

  The fin after the anodizing treatment can be hydrophilic or water repellent. Immediately after the treatment, it is hydrophilic (contact angle less than 50 °), and becomes water repellent (contact angle of 50 ° or more) over time. However, since the size of the droplets and ice droplets that can be formed on the fin surface is determined by the size and spacing of the pores, there is almost no difference in the effect regardless of whether it is hydrophilic or water-repellent. Play. That is, the method based on the anodizing treatment has little effect over time and can maintain the energy saving effect.

  In addition, here, the case where two unit coolers 12 are connected to the outdoor unit 11 has been described as an example. However, the present invention is not limited to this, and one unit may be used, or three or more units may be connected. I do not care.

  Naturally, a liquid reservoir may be connected to the liquid pipe part of the refrigerant circuit, or an accumulator may be connected to the suction pipe part of the compressor 21. Moreover, although the case where the compressor 21, the outdoor heat exchanger 22, and the blower 23 for outdoor heat exchangers were built in the outdoor unit 11 was demonstrated to the example, it is not restricted to this, Outdoor heat exchange The condenser 22 and the outdoor heat exchanger blower 23 may be of a remote condenser type in which they are placed separately from the compressor 21.

  In the above description, when the pores are formed on the entire outer surface of the heat exchanger, the pores are masked at both ends of the heat transfer tube so that the electrolyte does not enter the heat transfer tube and the pores are formed on the inner surface of the heat transfer tube. A method for preventing the formation is described. If pores are to be distributed inside the evaporator pipe as well as the outside, if the metal oxide film constituting the pipe is made of aluminum with valve action and connected as an anode, mask the pipe end. It is only necessary to anodic oxidation with the cathode provided outside the entire heat exchanger. Although pores may be formed on the entire inner surface of the pipe, in particular, by providing pores inside the pipe on the inlet side rather than on the outlet side of the evaporator, the inner surface of the pipe on the inlet side where the refrigerant is mainly in a liquid state is formed. The pores become the core of evaporation, and the evaporation from the liquid to the gas state is activated and the refrigerant is effectively evaporated from the liquid to the gas, leading to energy saving. On the other hand, since the refrigerant is mainly in a gaseous state on the outlet side, it is not necessary to form pores. FIG. 23 is an explanatory diagram in which pores are formed only on the refrigerant inlet side of the evaporator. Both ends of the heat transfer tube on the evaporator inlet side are opened so that the electrolyte enters the inside of the evaporator, and the evaporator outlet side Both ends of the heat transfer tube are closed by masking the tube. When completing the heat exchanger structure, the refrigerant inlet side and the refrigerant outlet side piping are connected by a U-bend as shown in the drawing so that the refrigerant flows.

  Although the case where a unit cooler is used as an indoor unit has been described as an example, any unit having a similar configuration may be used. For example, FIG. 24 shows an air conditioner (room air conditioner) having a flow path switching means 27 such as a four-way valve in the refrigerant circuit. In this case, the refrigerant flow discharged from the compressor 21 flows to the four-way valve 27. The direction can be changed by switching the refrigerant piping. As a result, when either the indoor heat exchanger 25 or the outdoor heat exchanger 22 is operated as an evaporator and the temperature of the refrigerant flowing through the heat transfer tube is 0 ° C. or less, the heat exchanger Since frost occurs, the use of an evaporator fin or heat transfer tube having a large number of pores has the same effect of reducing the thickness of the frost. Of course, air conditioners such as packaged air conditioners and building multi air conditioners have the same effect, and there is no problem even if a refrigerant reservoir such as a liquid reservoir or an accumulator is inserted in the refrigerant circuit. Needless to say, the same effect can be obtained no matter how many indoor heat exchangers or outdoor heat exchangers are connected.

  When applied to a room air conditioner, a packaged air conditioner, a building multi air conditioner, etc., when the heat exchanger according to the present invention is used as a heat exchanger disposed in a casing disposed on the outdoor side, the heat exchanger evaporates. During the heating operation in winter when the outside air temperature is low, the frost formation is delayed and energy is saved. Further, if pores are formed in the evaporator of the dehumidifier, it is possible to reduce the size.

  In addition, when applied to equipment that cools indoor articles such as packaged air conditioners, unit coolers, and showcases for facilities, the heat exchange according to the present invention is used as a heat exchanger disposed in a casing disposed indoors. If a heat exchanger is used, the heat exchanger operates as an evaporator, frost formation is delayed, and energy is saved.

  Any refrigerant can be used to circulate in the refrigeration cycle system. Natural refrigerants such as carbon dioxide, hydrocarbons and helium, alternative refrigerants such as HFC410A and HFC407C, and chlorine-free refrigerants or existing products can be used. Any of fluorocarbon refrigerants such as R22 and R134a may be used.

Moreover, you may use what performs heat exchange with water as a condenser like a heat pump type water heater or a heat pump chiller. Further, when CO ₂ is used as the refrigerant, the high pressure side is used in a supercritical state, and the refrigerant does not change phase in the gas cooler. Obviously, it may be used in any state.

  The compressor 11 may be of any type such as reciprocating, rotary, scroll, screw, etc., and may be a variable speed or a fixed speed.

  As described above, the refrigeration cycle apparatus of the present embodiment is produced by condensing moisture in the air on the evaporator surface by providing a large number of pores on almost the entire surface of the fins or heat exchanger of the evaporator. It makes it difficult for water droplets to coalesce into large water droplets, reduces the water droplets when solidification occurs, forms a thin and clean frost layer, reduces airway pressure loss, and improves frosting performance, It can save energy. Furthermore, the defrosting interval can be greatly extended, and wasteful energy generation unrelated to the original operation of the apparatus can be suppressed.

  FIG. 25 is an enlarged view of the surface of the heat exchanger fin of the present invention. In FIG. 25, the fins have different pore diameters depending on the positions where the pores formed on the surface are provided. In heat exchangers, the amount of frost on the windward side is generally large, and this determines the air path pressure loss. Therefore, if the frost thickness on the windward side can be reduced, the wind path pressure loss can be reduced. Can be small. Therefore, as shown in FIG. 25, for example, the number of pores on the air inflow side is increased or the pore depth is increased (left side in FIG. 25), and the number of outflow side pores is decreased or By reducing the depth of the pores (right side in FIG. 25), the fin anodizing time can be shortened. Since the absolute humidity of the air is large on the leeward side and the absolute humidity of the air is small on the leeward side, this structure can provide almost the same effect as when the front surface of the fin is anodized. Inexpensive, air passage pressure loss can be reduced, and energy can be saved. In order to change the diameter and depth of the pores in one fin, it is necessary to change the processing time and the like, and it is necessary to perform the processing with the masking position changed a plurality of times. In addition, since the amount of frost formation on the leeward side is small, only the fin on the leeward side is subjected to anodization treatment to form pores, and the fin on the leeward side is left untreated, and substantially the same effect is obtained.

  However, in a heat exchanger with a configuration that tends to cause a lot of frost on the leeward side rather than on the leeward side due to the characteristics of the refrigerant circuit, fin pitch, etc., increase the number of pores on the leeward side or increase the depth of the pores. If the number of pores on the inflow side is reduced or the depth of the pores is reduced, the processing time of the heat exchanger can be shortened.

  FIG. 26 shows the case where the pores are partially changed in the integrated fin. However, in the anodic oxidation, since the entire fin is immersed in the solution, the density of the pores is adjusted for each part in this structure. It takes time to do. Therefore, by adopting a structure in which fins are divided for each row as shown in FIG. 26, the density of the pores can be easily changed between the windward side and the leeward side. Further, as shown in FIG. 27, it is easier to perform anodizing only on the fin on the leeward side and use an untreated fin on the leeward side.

  As described above, the refrigeration cycle apparatus of the present invention uses fins in which a large number of pores are uniformly provided on almost the entire surface on the leeward side of the air flow, and pores are provided on the leeward side. Can be manufactured at a lower cost compared to the case where the entire surface of the fin is processed by using a fin having a smaller number of pores than a fin installed on the windward side or using a fin having a shallow pore depth. It is possible to reduce water droplets when solidification occurs, form a beautiful frost layer, reduce air path pressure loss, improve performance during frost formation, and save energy.

  Next, the structure and method for defrosting will be described. FIG. 28 shows a configuration diagram of, for example, a showcase that performs defrosting with a heater. In the case of a showcase, a compressor 21 and an outdoor heat exchanger 22 are provided in an outdoor unit 22 that is a heat source, and an indoor heat exchanger 25 is disposed in an indoor unit that is a showcase body that stores food frozen. The indoor heat exchanger is a condenser that releases high-temperature heat in the case of chlorofluorocarbon or HC refrigerant, or a gas cooler in the case of carbon dioxide refrigerant that is in a supercritical state, and the indoor heat exchanger is an evaporator. When a large amount of frost adheres to the evaporator 25, the cooling performance is lowered and the food temperature rises. Therefore, when the temperature in the showcase is detected and the set temperature is exceeded, the compressor 21 is stopped and brought close to the compressor, In addition, the heater disposed on the air inflow side is energized to perform a defrosting operation in which the evaporator 25 is heated to melt and remove the frost. Note that defrosting may be detected based on the accumulated operation time of the compressor or the operation time of the showcase.

  29 and 30 are explanatory views of defrosting of the hot water supply device. In the refrigeration cycle which is a heat source in the hot water supply device, the high-temperature refrigerant discharged from the compressor 21 supplies heat to the load side in the plate heat exchanger 33 and expands. It expands in the means 24, evaporates in the evaporator 22 and is radiated to the outdoor air. The water system on the load side circulates water with the pump 32, and the water that is the load of the plate heat exchanger 33 is heated from the heat source side and is sequentially stored as hot water in the tank 31 by the pump 32 at night. The hot water in the tank 31 is supplied as hot water to a bath, for example. If a large amount of frost adheres to the evaporator 22, the performance of the hot water supply device is lowered. In FIG. 29, the compressor is operated at 0 ° C. or lower, the compressor 21 is stopped at 0 ° C. or higher, and the evaporator blower 23 is moved to ventilate Defrost operation. On the other hand, in the configuration of FIG. 30, in the defrost operation in which the evaporator 22 defrosts, the high-temperature refrigerant from the compressor that is operated by opening the bypass valve 35 provided in the bypass pipe 34 is passed through the evaporator 22 to heat the heat transfer pipe. And remove the frost. In any of the defrosting operations of FIGS. 29 and 30, the blower 23 is operated to perform defrosting in a short time, but the pump 32 is stopped so that useless energy is not used in the water system on the load side. During this defrost operation, hot water is supplied from the tank 31 using the stored hot water.

  Although FIGS. 28 to 30 have been described with reference to examples of a showcase and a hot water supply device, they can be applied to other devices such as a refrigerator and an air conditioner. In addition to the above, it is possible to perform an operation to remove frost by various defrost operations, for example, by switching a four-way valve and allowing a high-temperature refrigerant to flow through a heat exchanger that was an evaporator. These defrosting operations are unnecessary operations for refrigeration, freezing, air conditioning, hot water supply, etc., which are the purpose of the original device, and should be completed in a short time without using as much energy as possible. For example, in a hot water supply device, it is likely to occur at dawn when water is heated to a high temperature. Therefore, it is necessary to detect the frost state from the refrigerant temperature and the outside air temperature and perform the defrost operation in a short time. Similarly, in refrigeration devices, the amount of frost formation is determined based on the cooling temperature, and defrosting operation is performed based on the defrosting interval set in advance according to the history time of the compressor or the operation time of the refrigeration device. By distributing a large number of fine pores on the evaporator surface such as the fins of the present invention, moisture in the air is adsorbed and the generation and growth of frost is delayed, or the frost is made uniform and thin and clean. It is possible to suppress the performance degradation during operation of the equipment, such as the heat transfer coefficient of the evaporator, the pressure loss of the blower, etc., and to extend the interval of the defrost operation to be set. However, if there is no need to perform a defrost operation that would hinder the operation of the equipment, it is not necessary to perform a defrost operation for a long time. Less need device is intended to be obtained. In some cases, it is possible to remove the heater for defrosting.

  In the refrigeration cycle apparatus of the present invention, a compressor, a condenser, expansion means, and an evaporator are connected by piping, a refrigerant is circulated in the piping to constitute a refrigeration cycle, and air is sent to the evaporator. Means, and a large number of pores are provided on almost the entire surface of the fins constituting the evaporator. In the refrigeration cycle apparatus of the present invention, a compressor, a condenser, expansion means, and an evaporator are connected by piping, a refrigerant is circulated inside the piping to constitute a refrigeration cycle, and air is sent to the evaporator. As the fins constituting the evaporator, fins provided with a large number of pores on almost the entire surface are provided on the windward side of the air flow, and pores are provided on the leeward side. Since no fins are used, a device with less energy consumption can be obtained.

  In the refrigeration cycle apparatus of the present invention, a compressor, a condenser, expansion means, and an evaporator are connected by piping, a refrigerant is circulated in the piping to constitute a refrigeration cycle, and air is sent to the evaporator. As a fin constituting the evaporator, a fin provided with a large number of pores on almost the entire surface is used on the windward side of the air flow, and the fin installed on the windward side is used on the leeward side. A fin having a small number of pores or a shallow pore depth is used. In addition, since the refrigeration cycle apparatus of the present invention is provided with a large number of pores on the surface of the heat transfer tube constituting the evaporator, an apparatus with less use energy can be obtained.

  In the refrigeration cycle apparatus of the present invention, a compressor, a condenser, expansion means, and an evaporator are connected by piping, a refrigerant is circulated in the piping to constitute a refrigeration cycle, and air is sent to the evaporator. And a large number of pores are provided on almost the entire outer surface of the heat transfer tube constituting the evaporator, thereby facilitating the moisture adsorption amount.

  The pores of the refrigeration cycle apparatus of the present invention are pores having a small diameter that do not penetrate the fins. In the refrigeration cycle apparatus of the present invention, the pores have a depth of 10 μm or more. In the refrigeration cycle apparatus of the present invention, the pore is a small diameter hole penetrating the fin. In the refrigeration cycle apparatus of the present invention, the pores are arranged such that the distance between the pores is 0.1 mm or less. In the refrigeration cycle apparatus of the present invention, since the pores have an equivalent diameter of the pores or the length of the shortest side of 0.1 mm or less, moisture in the air is stored in the pores not related to the original performance. It is done.

  The pores of the refrigeration cycle apparatus of the present invention are generated by subjecting the fins to an anodic oxidation treatment. The refrigeration cycle apparatus according to the present invention can be easily manufactured because the evaporator using the fins provided with the pores is arranged in a casing installed on the indoor side.

  The refrigeration cycle apparatus of the present invention includes flow path switching means such as a four-way valve for switching between the heat exchanger operating as the evaporator and the heat exchanger operating as the condenser during the refrigeration cycle, Since the heat exchanger using the fins provided with the pores is arranged in the housing installed in the above, efficient defrosting is possible.

  In the refrigeration cycle apparatus of the present invention, an evaporator using the fins provided with the pores and a condenser for exchanging heat with water are disposed in a casing installed outside the room, and water is supplied to the condenser. A circulating pump is provided to stop the pump during defrosting, so no wasted energy is used.

  In the refrigeration cycle apparatus of the present invention, a plurality of heat exchangers installed on the indoor side are connected. In addition, the refrigeration cycle apparatus of the present invention is effective in saving energy because a plurality of heat exchangers installed on the outdoor side are connected.

  Furthermore, even if the surface of the heat exchanger fins changes over time to a hydrophilic surface or a water-repellent surface, the present invention maintains the effect of delaying frost formation by adhering to the opening ridge line. It is a device that can continue to show energy-saving effects.

It is a refrigerant circuit figure of the refrigerating cycle device concerning Embodiment 1 of this invention. It is explanatory drawing regarding the production | generation of the water droplet in the unprocessed cooling surface which concerns on Embodiment 1 of this invention, growth, coalescence, and solidification. It is explanatory drawing regarding the production | generation of the water droplet on the cooling surface with many pores concerning this Embodiment 1 of this invention, growth, coalescence, and solidification. It is explanatory drawing of the water droplet produced | generated on the non-processed cooling surface which concerns on Embodiment 1 of this invention, and the cooling surface with many pores. It is explanatory drawing regarding the production | generation of the water droplet (condensed droplet) to the cooling surface which concerns on Embodiment 1 of this invention. It is another explanatory drawing regarding the production | generation of the water droplet (condensed droplet) to the cooling surface which concerns on Embodiment 1 of this invention. It is another explanatory drawing regarding the production | generation of the water droplet (condensed droplet) to the cooling surface which concerns on Embodiment 1 of this invention. 1 is a configuration explanatory diagram of a heat exchanger according to Embodiment 1 of the present invention. It is a schematic diagram of the moisture absorption isotherm which shows the adsorption | suction characteristic obtained by the capillary condensation phenomenon which concerns on Embodiment 1 of this invention. It is explanatory drawing explaining the relationship between the relative pressure which a capillary hole condensation and capillary condensation which concern on Embodiment 1 of this invention produce. It is an expansion schematic diagram of the surface of the heat exchanger which concerns on Embodiment 1 of this invention. It is a flowchart explaining the process flow of the anodizing process which concerns on Embodiment 2 of this invention. It is composition explanatory drawing of the anodizing apparatus which concerns on Embodiment 2 of this invention. It is explanatory drawing which shows the water vapor | steam adsorption isotherm of the formed pore which concerns on Embodiment 2 of this invention. It is explanatory drawing which shows the distribution curve of the formed fine hole diameter which concerns on Embodiment 2 of this invention. It is explanatory drawing which shows another water vapor | steam adsorption isotherm of the formed pore which concerns on Embodiment 2 of this invention. It is explanatory drawing which shows the distribution curve of another fine hole diameter formed based on Embodiment 2 of this invention. It is explanatory drawing which shows the water vapor | steam adsorption isotherm of another formed pore which concerns on Embodiment 2 of this invention. It is explanatory drawing which shows the distribution curve of another fine hole diameter formed based on Embodiment 2 of this invention. It is explanatory drawing which shows the water vapor | steam adsorption isotherm of another formed pore which concerns on Embodiment 2 of this invention. It is explanatory drawing which shows the distribution curve of another fine hole diameter formed based on Embodiment 2 of this invention. It is expansion explanatory drawing of many pores formed in the fin which concerns on Embodiment 2 of this invention. It is another structure explanatory drawing of the heat exchanger which concerns on Embodiment 2 of this invention. It is another refrigerant circuit figure of the refrigerating cycle device concerning Embodiment 2 of this invention. It is another structure explanatory drawing of the heat exchanger which concerns on Embodiment 2 of this invention. It is another structure explanatory drawing of the heat exchanger which concerns on Embodiment 2 of this invention. It is another structure explanatory drawing of the heat exchanger which concerns on Embodiment 2 of this invention. It is apparatus arrangement | positioning drawing of the refrigerating-cycle apparatus which concerns on Embodiment 2 of this invention. It is another apparatus arrangement | positioning figure of the refrigerating-cycle apparatus which concerns on Embodiment 2 of this invention. It is another apparatus arrangement | positioning figure of the refrigerating-cycle apparatus which concerns on Embodiment 2 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 Outdoor unit, 12 Indoor unit, 21 Compressor, 22 Outdoor heat exchanger, 23 Outdoor heat exchanger fan, 24 Expansion means, 25 Indoor heat exchanger, 26 Indoor heat exchanger fan, 27 Four-way valve (channel switching means) ), 30 heater, 31 tank, 32 pump, 33 plate heat exchanger, 35 times pass valve, 40 heat exchanger, 45 fin, 46 heat transfer tube, 61 DC power supply, 62 electrolyte, 63 electric field tank, 64 carbon plate, 65 Fin plate, 80 Refrigerator, 81 Refrigerator body, 82 chamber, 85 cooler, 86 Blower fan, 87 Heating heater, 88 Drain port, 91 Compressor, 92 Condenser, 94 Expansion valve, 95 Evaporator, 96 Blower for evaporator, 97 Bypass valve, 99 Water heat exchanger, 100 Hot water tank, 101 Water absorption pump.

Claims (8)

A compressor, a condenser or a gas cooler, an expansion means, a refrigerant cycle for connecting the evaporator to circulate the refrigerant, a blower means for blowing air to the evaporator, and a metal fin constituting the evaporator open to the inside The pores penetrating the metal fins and having a distance between them of about 10 nm to 100 nm and having a diameter or short side width of 2 nm to 100 nm can be attached to the moisture in the air. And a pore opening ridge line uniformly distributed in a large number on the surface of the metal fin forming an opening corner portion to which moisture in the air adheres to the pores. The refrigeration cycle apparatus according to claim 1, wherein the pores are formed by an anodizing process . A compressor, a condenser or a gas cooler, an expansion means, a refrigerant cycle for connecting an evaporator to circulate the refrigerant, a blower means for blowing air to the evaporator, an evaporator and an oxide film having a valve action The evaporator is anodized using a metal part such as aluminum as an anode, and the distance between the holes on the outer surface of the evaporator is about 10 nm to 100 nm or less in the anodization , and the diameter or short side width is It includes a pore and which can be attached to the interior moisture of the air which is formed as a 2nm or 100nm or less, adhesion of moisture of the air in the pores formed many distributed to the outer surface of the evaporator with the shape of the opening ridge of maintaining the heat treatment after the anodic oxidation, that the refrigerant in the evaporator to form the pores in the heat transfer tube surface that circulates in said anodizing Refrigeration cycle apparatus according to claim. The refrigeration cycle apparatus according to claim 3, wherein the pores on the inner surface of the heat transfer tube are provided on an inner surface on the inlet side of the evaporator . 5. The refrigeration cycle apparatus according to claim 3, wherein the pore has a depth of 10 μm or more and about 100 μm or less . A defrosting apparatus that uses the refrigeration cycle apparatus according to any one of claims 1 to 5 and that heats the evaporator to remove frost attached to the evaporator in the vicinity of the evaporator provided with the pores. A refrigeration / air-conditioning system that is arranged. Flow path switching means that uses the refrigeration cycle apparatus according to any one of claims 1 to 5 and switches the flow of the refrigerant that is provided in the refrigerant cycle and in which a heat exchanger operates as the evaporator. The refrigeration / air-conditioning apparatus is characterized in that the flow of the refrigerant is switched by the flow path switching means to flow a high-temperature refrigerant through the heat exchanger to remove frost adhering to the heat exchanger. A pump that uses the refrigeration cycle apparatus according to any one of claims 1 to 5 and flows water that exchanges heat with a refrigerant that circulates in the refrigerant cycle in the condenser, and the evaporator provided in the refrigerant cycle. And a flow path switching means for flowing high-temperature refrigerant from the condenser or gas cooler side, and switching the flow path switching means to stop the pump when flowing the high-temperature refrigerant to the evaporator. Hot water supply device.

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