JP2004263959A - Absorption core of absorption type heat pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance an absorption speed while securing the durability of an absorption core in an absorption type heat pump. <P>SOLUTION: The absorption speed required for the absorption core of the absorption type heat pump can be provided by using a material having a heat conductivity of 0.5 W/m × K to 2.0 W/m × K as an adhesive to adhere and fix an adsorbent 50 to a tube 33. The high heat conductivity of the adhesive can be obtained by using a material of including graphite or silicon carbide in resin as a filler for the adhesive. The content of the graphite is set to 5 wt.% to 40 wt.%; the content of the silicon carbide is set to 5 wt.% to 50 wt.%; the heat conductivity is set to 0.5 W/m × K to 2.0 W/m × K; and prescribed adhesive strength required from the viewpoint of securing the durability of the absorption cores 11 and 12 can be secured. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an adsorption core of an adsorption heat pump that utilizes the fact that an adsorbate such as water is adsorbed and desorbed by cooling and heating an adsorbent.
[0002]
[Prior art]
In the adsorption core of the adsorption heat pump, the temperature of the adsorbent (for example, zeolite or silica gel) is reduced to a cooling temperature (for example, an outside air temperature for a vehicle) and a heat source temperature (for example, about 90% of an engine cooling water temperature for a vehicle). ° C), and the cooling capacity of the apparatus is determined by the amplitude of the amount of adsorption and desorption of the adsorbate (eg, water) and the adsorption and desorption rate during the period. The amplitude of the amount of adsorption and desorption is determined from the water absorption characteristics of the adsorbent itself, but it is important for the adsorption speed to determine how the adsorbent reaches a predetermined temperature.
[0003]
The adsorption core adheres the adsorbent to the heat exchange member having the tube with a powder adhesive, and the heat of the heat exchange fluid flowing in the tube is transmitted in the order of the heat exchange member, the adhesive, and the adsorbent. become. Therefore, in order to transfer heat to the adsorbent as quickly as possible, it is necessary to improve the thermal conductivity of the adhesive.
[0004]
[Problems to be solved by the invention]
By the way, in an adsorption core of a conventional adsorption heat pump, an adhesive in which a resin component appropriately contains a filler is used. Generally, the thermal conductivity of a resin is about 0.2 W / m · K. In the case of a general-purpose adhesive, a filler (for example, calcium carbonate, magnesium oxide, or the like) is mixed with the adhesive to improve the thermal conductivity. I'm trying.
[0005]
However, conventionally, the value of the thermal conductivity of the adhesive is about 0.4 W / m · K even when the thermal conductivity of the adhesive is maximized while satisfying the adhesive strength required for the adhesive for the adsorption core. When the content of the filler was set within a range where the adhesive strength required for the adhesive could be secured, the required adsorption rate could not be secured due to insufficient thermal conductivity. Therefore, it has been difficult to increase the suction speed of the suction core while securing the adhesive strength of the adhesive.
[0006]
In view of the above, an object of the present invention is to increase the suction speed while securing the adhesive strength of the adhesive of the suction core.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, a heat exchange member (30) having a tube (33) through which a heat exchange fluid flows, and a surface of the heat exchange member (30) are bonded with an adhesive. And an adsorbent (50) capable of adsorbing and desorbing adsorbates by being cooled and heated by a heat exchange fluid, wherein the adhesive is: The thermal conductivity is 0.5 W / m · K or more and 2.0 W / m · K or less. When such an adhesive is used, it is possible to secure the suction speed required for the suction core.
[0008]
Further, in order to achieve such a high thermal conductivity and to secure the bonding strength required for the adhesive for the adsorption core, either one of graphite and silicon carbide as the filler as in the invention of claim 2 is used. , Or a combination of the two, and it is desirable to use an epoxy resin as the resin component as in the invention of claim 7.
[0009]
By the way, when the content of the filler is set within a range capable of securing the adhesive strength required as the adhesive for the adsorption core, the thermal conductivity of the conventional adhesive containing calcium carbonate in the epoxy resin is 0.4 W / M · K, whereas the thermal conductivity of the adhesive according to the third aspect of the invention is improved to a maximum of about 2.0 W / m · K, thereby ensuring the durability of the adsorption core. It has become possible to increase the adsorption speed.
[0010]
By setting the content of graphite in the adhesive to 5% by weight or more and 40% by weight or less as in the invention according to claim 3, a high thermal conductivity can be obtained, and a high thermal conductivity and a high adsorbent core can be obtained. Can achieve both of securing the adhesive strength required for the adhesive of the present invention. In order to realize a higher thermal conductivity and maintain the adhesive strength for a long period of time, the graphite content is desirably 10% by weight or more and 30% by weight or less.
[0011]
Further, as in the invention according to claim 5, by setting the content of silicon carbide in the adhesive to 5% by weight or more and 50% by weight or less, high thermal conductivity can be obtained, and high thermal conductivity can be obtained. It is possible to achieve both of securing the adhesive strength required as the adhesive for the suction core. In order to realize a higher thermal conductivity and maintain the adhesive strength for a long period of time, it is desirable that the content of silicon carbide be 10% by weight or more and 40% by weight or less.
[0012]
In addition, the code | symbol in the parenthesis of each said means shows the correspondence with the concrete means described in embodiment mentioned later.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention shown in the drawings will be described. FIG. 1 is a schematic overall configuration diagram of an adsorption heat pump, and FIG. 2 is a perspective view of an adsorption core of the adsorption heat pump according to the present invention.
[0014]
In FIG. 1, the adsorption heat pump 1 includes first and second adsorption cores 11 and 12. These adsorption cores 11 and 12 are accommodated in closed containers 14 and 15, respectively, and the closed containers 14 and 15 are provided with entrances and exits 16 and 17 for gas adsorbate (steam in this embodiment). .
[0015]
Three-way switching valves 18 and 19 are connected to the entrances and exits 16 and 17, respectively. Between the three-way switching valves 18 and 19, a condenser 20 for liquefying the adsorbate, gas-liquid separation of the adsorbate, and liquid A receiver 21 that temporarily stores the adsorbate, a pump 22 that sends the liquid adsorbate, and an evaporator 23 that evaporates the liquid adsorbate and exchanges heat with the outside air are connected in series, thereby forming an adsorbate circuit 25. ing. The adsorbate circuit 25 is filled with a required amount of adsorbate, for example, water in the case of the present embodiment.
[0016]
Next, the structure of the suction cores 11 and 12 will be described in detail with reference to FIG. The adsorption cores 11 and 12 each include a heat exchanger (heat exchange member) 30 and a number of particulate adsorbents 50 adhered to the surface of the heat exchanger 30.
[0017]
The heat exchanger 30 includes header tanks 31 and 32 at both ends, and a plurality of plate-like tubes 33 through which a heat exchange fluid flows are arranged in parallel at a predetermined distance between the header tanks 31 and 32. ing. Corrugated fins (heat transfer fins) 34 are fixed between the tubes 33 by brazing, welding, or bonding. The header tanks 31 and 32 are made of a material having excellent moldability, such as resin, aluminum, and copper, and the tube 33 and the fins 34 are made of a material having excellent heat conductivity, such as aluminum and copper.
[0018]
Then, in the order of the header tank 31 on the inlet side, the tube 33, and the header tank 32 on the outlet side, a cooling fluid (for example, a relatively low-temperature fluid from an outdoor heat exchanger, a heat exchange fluid in the claims) or a heating fluid (for example, Engine cooling water (a heat exchange fluid in the claims) flows.
[0019]
A large number of particulate adsorbents 50 are made of, for example, zeolite or silica gel, and are filled in gaps formed by the tubes 33 and the fins 34. Each particle of the adsorbent 50 is bonded and fixed to the tube 33 and the fin 34 with an adhesive.
[0020]
The adsorbent 50 adsorbs an adsorbate (for example, water vapor or an aqueous alcohol solution) with a high capacity in a cooled state, and the adsorption capacity gradually decreases with the adsorbate being adsorbed. It has the property that the adsorbate that has been desorbed is desorbed to regenerate the adsorption capacity.
[0021]
Therefore, the adsorbent 50 exchanges heat with the heat exchange fluid flowing through the tube 33 by heat conduction through the tube 33 and the fins 34, and adsorbs gas adsorbate (water vapor in the present embodiment) by being cooled. The gas adsorbate can be desorbed by heating.
[0022]
In such a configuration, the first and second adsorption cores 11 and 12 are controlled by a control device such as a microcomputer (not shown) so that when one is on the desorption side for desorbing the gas adsorbate (water vapor), the other is. Are alternately switchable so that is on the adsorption side for adsorbing the gas adsorbate from the evaporator 23.
[0023]
Specifically, in FIG. 1, when the first suction core 11 is used as the desorption side and the second suction core 12 is used as the suction side, the three-way switching valves 18 and 19 are set to the solid line positions in FIG. The inlet / outlet section 16 of the closed vessel 14 on the core 11 side is in communication with the condenser 20, and the inlet / outlet section 17 of the closed vessel 15 on the adsorption core 12 side is in communication with the evaporator 23. Further, a heating fluid is supplied to the suction core 11 side, and a cooling fluid is supplied to the suction core 12 side.
[0024]
When the first suction core 11 is used as the suction side and the second suction core 12 is used as the desorption side, the three-way switching valves 18 and 19 are set to the dotted line positions in FIG. And the evaporator 23 are in communication with each other, and the entrance and exit 17 of the closed vessel 15 on the adsorption core 12 side are in communication with the condenser 20. A cooling fluid is supplied to the suction core 11 and a heating fluid is supplied to the suction core 12.
Next, an adhesive for adhesively fixing the adsorbent 50 to the tube 33 and the fin 34 will be described.
[0025]
Conventionally, an adhesive containing calcium carbonate as a filler in a resin is often used. In this embodiment, an adhesive containing graphite in an epoxy resin or an adhesive containing silicon carbide in an epoxy resin is used.
[0026]
FIG. 3 is a characteristic diagram showing the results of evaluating the relationship between the filler content and the thermal conductivity for adhesives having different filler materials. As is apparent from FIG. 3, the adhesive of the present embodiment in which graphite or silicon carbide is contained in the epoxy resin has a higher thermal effect than the adhesive in which calcium carbonate prepared in this case is contained in the epoxy resin for comparison. It was confirmed that the conductivity was significantly improved.
[0027]
Incidentally, the adhesive for the suction cores 11 and 12 of the suction heat pump 1 is required to have a predetermined adhesive strength from the viewpoint of ensuring the durability of the suction cores 11 and 12. In order to ensure this predetermined adhesive strength, the content of the graphite filler is set to 40% by weight or less for the adhesive containing graphite, and the content of the silicon carbide filler is set for the adhesive containing the silicon carbide filler. It was confirmed that the content should be set to 50% by weight or less.
[0028]
Therefore, an adsorption core (hereinafter referred to as a comparative example) in which an adsorbent 50 is adhered and fixed with an adhesive having a thermal conductivity of 0.4 W / m · K in which 33% by weight of calcium carbonate is added to an epoxy resin prepared as a comparative example. An adsorbing core) and an adsorbing core (hereinafter referred to as evaluation adsorbing core 1) in which the adsorbent 50 is bonded and fixed with an adhesive containing 5% by weight of graphite and having a thermal conductivity of 0.5 W / m · K. An adsorption core (hereinafter referred to as an evaluation adsorption core 2) in which an adsorbent 50 is adhered and fixed with an adhesive containing 40% by weight of graphite in an epoxy resin and having a thermal conductivity of 2.0 W / m · K; An adsorption core (hereinafter referred to as an evaluation adsorption core 3) is prepared by adhering and fixing the adsorbent 50 with an adhesive having a thermal conductivity of 2.0 W / m · K in which resin contains 50% by weight of silicon carbide. The adsorption speed of each of the adsorption cores was evaluated.
[0029]
FIG. 4 shows the evaluation results, in which the horizontal axis represents the elapsed time and the vertical axis represents the value obtained by standardizing the amount of adsorbate adsorbed by the saturated amount of adsorbate. As is clear from FIG. 4, the slope of the increase in the amount of adsorption is larger in the evaluation adsorption core 1 than in the comparative adsorption core, and the adsorption speed is large enough to ensure the performance required for the adsorption heat pump. Has become. In addition, the suction speed of the evaluation suction cores 2 and 3 is higher than that of the evaluation suction core 1, and the difference is particularly remarkable in the operation time (60 to 300 seconds) of the suction and desorption in actual use. Is appearing.
[0030]
(Other embodiments)
In each of the above embodiments, the fin 34 is a corrugated fin, but the fin shape is not limited to this. For example, it may be a plate fin. Further, the heat exchanger 30 is not limited to the tube / fin type, but may be a type having only tubes without fins.
[0031]
In addition, the shape of graphite or silicon carbide as a filler to be contained in the resin is desirably acicular or scaly, and more desirably, the aspect ratio is 2 or more, thereby further improving the thermal conductivity of the adhesive. it can.
[Brief description of the drawings]
FIG. 1 is a schematic overall configuration diagram of an adsorption heat pump.
FIG. 2 is a perspective view of a suction core of the suction heat pump according to the present invention.
FIG. 3 is a characteristic diagram showing a relationship between a filler content and a thermal conductivity.
FIG. 4 is a characteristic diagram showing a relationship between an elapsed time and a suction amount of a suction core.
[Explanation of symbols]
11, 12: adsorption core, 30: heat exchanger (heat exchange member), 33: tube,
50 ... adsorbent.

Claims (7)

A heat exchange member (30) having a tube (33) through which a heat exchange fluid flows, and an adhesive adhering to the surface of the heat exchange member (30) with an adhesive, and being cooled and heated by the heat exchange fluid; An adsorbent core (11, 12) comprising an adsorbent (50) capable of adsorbing and desorbing the adsorbent, wherein the adhesive has a thermal conductivity of 0.5 W / m · K or more. An adsorption core for an adsorption heat pump, wherein the adsorption core has a pressure of not more than 0.0 W / m · K. 2. The adsorption core of the adsorption heat pump according to claim 1, wherein the adhesive includes a resin component containing one of graphite and silicon carbide as a filler. 3. The adsorption core according to claim 2, wherein the adhesive has a graphite content of 5% by weight or more and 40% by weight or less. The adsorption core of the adsorption heat pump according to claim 2, wherein the content of the graphite in the adhesive is 10% by weight or more and 30% by weight or less. The adsorption core according to claim 2, wherein the adhesive has a content of the silicon carbide of 5% by weight or more and 50% by weight or less. The adsorption core according to claim 2, wherein the adhesive has a content of the silicon carbide of 10% by weight or more and 40% by weight or less. 7. The suction core of the suction heat pump according to claim 3, wherein the resin component of the adhesive is an epoxy resin.

Images