JPH10286460A - Adsorbent for forming, and adsorption heat exchanger having integrally formed structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adsorbent for forming and an integrally structured adsorption heat exchanger using the adsorbent in which the effective heat conductivity of an adsorbent layer is improved, the heat conductivity of a heat transferring member surface forming a passage of hot water or cooling water for adsorption and desorption is enhanced and the adsorption performance of the adsorbent is not damaged. SOLUTION: The integrally structured adsorption heat exchanger 15a formed by dipping is constituted of plural heat transfer tubes 10 made of copper and forming the passage for hot water or cooling water, of plural flat fins 11 made of aluminum, an aluminum alloy, copper, a copper alloy or the like and of the dip formed adsorbent layer 14 formed by dipping to cover the fins and the heat transfer tubes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adsorbent for an adsorption refrigerator and an adsorption heat exchanger for containing the adsorbent, and more particularly to an adsorbent for molding which can be integrally molded with a heat conductive binder with improved adsorption / desorption characteristics. The present invention relates to a heat exchanger having a single-piece structure and an adsorbent.

[0002]

2. Description of the Related Art An adsorption refrigerator is a refrigerator that generates cold heat using heat as a heat source by utilizing a heat generation and absorption phenomenon caused by a reversible reaction between a solid adsorbent such as silica gel and water as a refrigerant. Comprises a regeneration step and an adsorption step, in which the two solid adsorbent heat exchangers (hereinafter referred to as adsorption heat exchangers) are alternately operated. FIG. 7 shows a schematic configuration of a conventional adsorption refrigerator.

For example, as shown in FIG. 7, the regeneration step is performed by an adsorption heat exchanger 50, and the adsorption step is performed by an adsorption heat exchanger 51.
In this case, the switching valve and the steam valve with the black mark are closed, and the switching valve and the steam valve with the white mark are opened. In this case, the adsorption heat exchanger 50 in the vacuum vessel
When the hot water for regeneration 71 is introduced and heated via the switching valve 61, the water vapor desorbed from the built-in adsorbent is discharged to the condenser 52 via the steam valve 56. In the condenser 52, the released steam is liquefied by the condensing cooling water 72. The water condensed and dropped is stored in the lower part of the evaporator 53, and the regeneration of the adsorbent contained in the adsorption heat exchanger 50 ends.

On the other hand, an adsorption heat exchanger 51 in another vacuum vessel
, Cooling water 73 for adsorption is introduced through the switching valve 63, and the built-in adsorbent is cooled and shifts to a state where adsorption is possible. Water vapor generated in the evaporator 53 via the pump 53a and the atomizer 53b is sent to the adsorption heat exchanger 51 via the steam valve 57 and is adsorbed by the adsorbent in the adsorbable state. At this time, in the evaporator 53, the water vapor generated via the sprayer 53b takes away the latent heat of evaporation from the fluid to be cooled 60 in the process of generation. As a result, cold water can be produced. That is, the adsorbent contained in the adsorption heat exchanger 51 is placed in the adsorption step, and the evaporator 53 supplies cold heat to the fluid 60 to be cooled.

When the amount of adsorption and desorption of water vapor approaches saturation, the switching valve 61 is switched to 62, 65 to 67, 63 to 64, and 68 to 66. As a result,
Water vapor is adsorbed by the adsorption heat exchanger 50, and the adsorption heat exchanger 5
In step 1, the steam is desorbed, and the switching operation is repeated thereafter.

FIG. 8 shows the construction of the adsorption heat exchangers 50 and 51.
(A) and (B). FIG. 8A is a schematic view of a heat exchanger having a plate-type heat conducting member. Activated carbon, alumina, activated alumina and silica gel can be considered as the adsorbent, but silica gel is used because it can effectively utilize exhaust heat of 60 to 80 ° C. and is relatively easy to obtain. Is used. As shown in FIG. 8 (A), the adsorption heat exchanger fills, for example, particulate adsorbent (silica gel) 76 on both sides of a heat transfer member 75 forming a passage for hot water for regeneration or cooling water for adsorption. Wire mesh 79 for holding down the adsorbent
Are used as a set of several dozen. The thickness Y of the adsorbent-filled layer is determined in consideration of heat transfer and mass transfer. In addition to the above structure, as shown in FIG. 8B, a heat transfer tube 77 which is a heat transfer member forming a passage for the hot water or the cooling water, and a plurality of heat transfer tubes provided at right angles to the heat transfer tube and at equal intervals. And a heat transfer tube 7 formed from the outside of the fin through the gap between the fins.
7 is filled with an adsorbent 76 so as to surround the outer periphery of the wire 7 and covered with a wire mesh 79 or the like from the outside.
(Japanese Patent Application No. 4-159308)

In any of the above structures, since the adsorbent 76 and the adsorbent 76 and the fin 78 or the surface of the heat transfer member 75 are formed by point contact, the heat transfer from the heat transfer member to the adsorbent is performed. The transmission of heat must rely on the conduction of heat between solids and solid gases with poor thermal conductivity. As a result, in the adsorption heat exchanger, the heat transfer performance is poor, and the preheating and heat supply due to the adsorption and desorption of water vapor are insufficient, so that the adsorption and desorption speed is reduced, and the adsorbents that fully exhibit the adsorption and desorption functions are limited. And contributed to the expansion of the device.

To solve these problems, various proposals have conventionally been made, and Japanese Patent Application Laid-Open No. 4-143558 discloses a proposal a.
However, proposal b is disclosed in JP-A-8-200876, and proposal c is disclosed in JP-A-8-27085. Proposal a is that a mixed slurry is formed by the adsorbent and the metal promoter, the slurry and the heat transfer member are charged into a mold, and the mixture of the adsorbent and the metal promoter is integrally fired on the heat transfer member. Proposal b proposes that the heat transfer member surface is coated with powdery silica gel containing an adhesive having a dehydrating effect and fixed, and then coated or embedded to cover the heat transfer member surface with the silica gel. The invention is characterized by being integrated, and the proposal c is characterized by providing a heat conductive layer between the surface of the heat transfer member and the adsorbent.

[0009] Looking at the conventional proposals from the above proposals a to c, in the proposal a, a mixture of the adsorbent and the metal promoter is formed, and the mixture and the heat transfer member are integrated by sintering. It is trying to make it. In this case, the heat transfer coefficient can be improved by mixing the metal promoter, but a dense polycrystalline body is formed in the mixture because a sintering unit is used for bonding the mixture and the heat transfer member. Therefore, mass transfer at the time of adsorption and desorption of the refrigerant becomes difficult, adsorption and desorption are limited to only the adsorbent on the surface, and a decrease in efficiency is inevitable. Next, in Proposal b, a mixture is formed by an adsorbent and a dehydrating adhesive to form a slurry, and the slurry is applied to a heat transfer member, coated or embedded, and dried and integrated. As a result, the contact area between the heat transfer member and the adhesive and between the adhesives is enlarged as compared with the conventional point contact, but the thermal conductivity of the adhesive itself is not considered at all. There is no great expectation for improvement in performance, and no consideration is given to mass transfer of refrigerant from outside. Also,
In proposal c, a heat conductive layer is provided on the surface of the heat transfer member,
Since the particulate adsorbent is filled through the heat conduction layer, the heat conduction between the adsorbent and the heat transfer member can be improved by increasing the contact area as compared with the conventional point contact. There is no improvement in the heat transfer during this time.

[0010]

Incidentally, the heat transfer performance U of the adsorption heat exchanger, the effective thermal conductivity λ _eff of the adsorbent layer, the thickness S _{ad of} the adsorbent layer, and the heat transfer coefficient on the heat transfer member surface The following relational expression holds between h _w , the transmission member thickness _{Sw, the} heat conductivity λ _w , and the heat transfer coefficient h _ext of the heat medium (refrigerant). 1 / U = 1 / h _w + S _w / λ _w + S _ad / λ _eff + 1 / h _{ext In the} above equation, the effective heat conductivity λ _eff of the adsorbent layer and the heat transfer coefficient h _{w on} the heat transfer member surface are calculated. If the improvement is achieved, the heat transfer performance U can be improved.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has an object to improve the effective thermal conductivity λ _eff of the adsorbent layer and to improve the heat transfer of the surface of a heat transfer member which forms a passage for hot or cold water for adsorption and desorption. It is an object of the present invention to provide a molding adsorbent that does not impair the adsorption performance of the adsorbent while improving the efficiency of the adsorbent, and an adsorption heat exchanger having an integral structure using the adsorbent.

[0012]

The gist of the present invention will be described below. That is, in order to improve the effective thermal conductivity λ _eff of the adsorbent layer, the graphite powder is mixed with the particulate silica gel so as to fill each gap of the particulate silica gel group and the gap between the heat transfer material surface with the high thermal conductive agent. To form a high thermal conductivity adsorbent. Next, in order to improve the heat transfer coefficient h _{w on} the heat transfer member surface,
The mixed high thermal conductive adsorbent is molded into a heat transfer member and formed into a highly polymerizable and swellable and expandable polymer network to enable the formation of a highly plastic and strong molded surface. After the organic binder is additionally mixed, it is formed into a slurry in water. Further, the mass transfer of the refrigerant from the outside is facilitated by adding a porous inorganic binder.

The compounding ratio of the cellulose-based organic binder and the porous inorganic binder is based on the premise that the adsorbing performance of the adsorbent is not impaired, and in particular, it is necessary to avoid macroblocks and mesopores of silica gel from being blocked. No. Further, in order to maintain a large adsorption capacity even under a low relative pressure, it is necessary to consider the expansion of the pore volume and the specific surface area.

Further, the heat transfer member is immersed in a solution in which a powdery or granular material based on the above mixing ratio is dispersed in a mixed slurry or paste form, paste-processed, molded, air-dried, and heat-dried to form an integrated body. Form an adsorption heat exchanger with a molded structure.

Therefore, the invention according to claim 1 is the adsorbent for an adsorption type refrigerator, wherein silica gel, graphite, an organic binder and an inorganic binder are mixed, and water is added and dispersed to form a slurry or paste. , A molding adsorbent.

According to a second aspect of the present invention, there is provided a heat exchanger provided with a heat transfer pipe and a heat transfer fin.
By drying treatment before and after, it was immersed in the adsorbent,
It is an adsorption heat exchanger with an integral molding structure.

According to a third aspect of the present invention, there is provided a heat exchanger provided with a heat transfer pipe and a heat transfer fin. This is an adsorption heat exchanger having an integrally molded structure that has been molded by the preceding and following mold drying processes.

According to a fourth aspect of the present invention, there is provided a molded adsorbent molded and dried into a predetermined shape from the molded adsorbent according to the first aspect, and the adsorbent is accommodated in a lower portion and an upper portion serves as a sunlight irradiation space. An adsorbent heat exchanger for driving solar light, comprising a heat insulating container forming a space for adsorbing and desorbing refrigerant vapor and a solar heat drive.

[0019]

The high thermal conductivity of graphite makes it possible to improve the effective thermal conductivity of the adsorbent layer, and the admixture of a suitable amount of a cellulose organic binder makes it possible to adsorb water vapor. Expectation of function and swellable polymer network that can be expanded and stretched can be expected to maintain the strength of a strong and plastic molded surface. In addition, an effect of facilitating the mass transfer of the refrigerant vapor in the adsorbent layer can be expected by blending an appropriate amount of the porous inorganic binder. Also,
The heat transfer body is immersed in the forming adsorbent or air-dried after paste processing and low-temperature drying at about 70 ° C. to dry while maintaining saturated steam, thereby preventing cracks on the forming surface.

In the invention according to claim 4, when the adsorption heat exchanger for driving sunlight is constituted by using the molding adsorbent according to claim 1, graphite, which is a heat conducting member, is black. Therefore, it is possible to form a highly efficient solar-driven heat exchanger that is optimal for absorbing solar heat.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to an embodiment shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not merely intended to limit the scope of the present invention, but are merely illustrative examples unless otherwise specified. Absent. FIG.
FIG. 2 is a perspective view showing a schematic configuration of an adsorption heat exchanger which is integrally formed by immersion molding using the molding adsorbent of the present invention, and FIG. FIG. 2 is a perspective view showing a schematic configuration of an adsorption heat exchanger having an integral structure.

As shown in FIG. 1, the immersion-molded adsorption heat exchanger 15a having an integral structure comprises a plurality of copper heat transfer tubes 10 forming passages for hot water or cooling water, and a right angle with the heat transfer tubes 10. A plurality of flat fins 11 made of aluminum, an aluminum alloy, copper, a copper alloy, etc., provided at equal intervals and in parallel with each other, and a dip-formed sorbent layer covering the fins 11 and the heat transfer tube 10 14 and.

The immersion-formed adsorbent layer 14 is made of a forming adsorbent formed in a slurry state. An example of a method of adjusting the adsorbent and processing conditions are described below. 80.8 parts by weight of silica gel powder of 42 mesh or less and graphite fine particles 9.
0 parts by weight, 3.55 parts by weight of a cellulose-based organic binder and a powdery or fibrous inorganic binder made of zeolite 6.
Mix 63 parts by weight for 15 minutes, add 55.6 parts by weight of water
The mixture is dispersed and mixed for a minute to form a slurry-like solution. A heat transfer member consisting of the heat transfer tube 10 and the fins 11 shown in FIG. 1 is immersed in the above solution, air-dried for 2 days in the air after the immersion, and a drying process at about 70 ° C. for 36 hours. Thereafter, the immersion-molded adsorbent layer 14 shown in FIG. 1 is formed to constitute an integrated heat exchanger 15a.

FIG. 2 shows a schematic configuration of an adsorption heat exchanger 15b which is formed integrally by molding using an adsorbent for molding. The adsorption heat exchanger 15b having an integral structure formed by the above-described molding is provided with a plurality of copper heat transfer tubes 10 forming passages of hot water or cooling water, and crossing the heat transfer tubes 10 at right angles and equidistantly and in parallel. Flat fins 11 made of a plurality of aluminum, aluminum alloy, copper, copper alloy, etc.
And a molded adsorbent layer 12 formed by paste processing between the fins, and a groove 13 formed before and after the middle of the molded adsorbent layer 12.

The molded adsorbent layer 12 is composed of a molding adsorbent formed in the form of a paste. An example of a method for adjusting the adsorbent and processing conditions will be described below. 86.2 parts by weight of silica gel powder having a particle size of 42 mesh or less, and graphite fine particles 4.
35 parts by weight, 4.35 parts by weight of a cellulose-based organic binder, and 5.08 parts by weight of a fibrous inorganic binder with zeolite are mixed for 15 minutes, 39.6 parts by weight of water is added, and the mixture is dispersed and mixed for 60 minutes to form a paste. Then, the heat transfer member composed of the heat transfer tube 10 and the fin 11 shown in FIG. 2 is subjected to paste processing with the above paste-form adsorbent, then sandwiched between Teflon and a stainless steel perforated plate, and allowed to stand in the air for 3 days and air-dried. After performing the drying process at approximately 70 ° C. for 36 hours, FIG.
The adsorbent heat exchanger 15b is formed by forming the molded adsorbent layer 12 shown in FIG. The upper and lower grooves 13 in FIG. 2 are formed at the same time as the pressing force by making the shape of the perforated plate a grooved shape.

Among the mixed members constituting the forming adsorbent for forming the immersion-formed adsorbent layer and the molded adsorbent layer, graphite is a highly heat-conductive member, and the effective heat conductivity λ _eff of the adhesive layer is improved. Use for The cellulosic organic binder has a function of adsorbing water vapor and a swellable and stretchable polymer network to form a strong and highly plastic molded surface and maintain strength. In addition, an effect of facilitating the mass transfer of the refrigerant vapor in the adsorbent layer can be expected by blending an appropriate amount of the porous inorganic binder. In addition, the heat transfer body is immersed in a molded adsorbent or air-dried after paste processing and at about 70 ° C.
By drying at low temperatures before and after, drying is performed while maintaining saturated steam to prevent cracks on the molding surface. In addition,
The organic binder does not impair the adsorption performance of silica gel as an adsorbent, and it is necessary to avoid blocking macropores and mesopores of silica gel. Care has been taken to increase the pore volume and specific surface area.

The molded article No. having the immersion-molded adsorbent layer 14 and the molded-molded adsorbent layer 12 described above. Comparative measurement of heat transfer characteristics and adsorption characteristics was carried out for No. 1 and molded product B and a conventional crushed silica gel type. As a result, heat transfer performance U is molded adsorbent in the desorption initial 62.2W / m ₂ K, molding adsorbent in crushing the silica gel 44.8W / m ₂ K, also during the desorption period 61.5W / m ₂ K, crushed silica gel was 25.9 W / m ₂ K.

As shown in the above results, it is possible to obtain high heat transfer performance, increase the regeneration temperature, decrease the adsorption temperature, and increase the cycle refrigerant circulation amount.
No. of each molded product. 1 and the adsorption properties for crushed silica gel. In addition, the above results can reduce the adsorption and regeneration cycle time. Also, the size can be reduced. The reason why the grooves 13 are provided in the molded adsorbent layer 12 is to make the mass transfer of the refrigerant easier,
Thus, the cycle time of the molded product B can be reduced.

FIG. 5 is a schematic diagram showing a schematic configuration of an adsorption heat exchanger for driving sunlight using the adsorbent for molding of the present invention. As shown in the figure, the adsorption heat exchanger 16 for driving sunlight of the present invention comprises a molded adsorbent 20, a heat insulating container 21 for containing the adsorbent, and a pressure-resistant heat-resistant sealed structure provided on the upper part of the heat insulating container. For example, as shown in FIG. 6, the light transmitting member 25 is made of glass or the like, and the solar light irradiation space and the adsorption / desorption space 22 formed by the pressure resistance, heat resistance, and airtight structure. Fig. 6 (A) during the daytime
As can be seen from the above, in the solar heat adsorption heat exchanger 16, the adsorbent is heated and desorbed and regenerated, and the generated refrigerant vapor (water vapor) 24 is introduced into the condenser 17 and is condensed by the condensing cooling water. On the other hand, at night, radiant cooling is performed as shown in FIG. 6 (B), and the adsorbent is cooled to increase the adsorbent adsorption capacity. Here, by operating the condenser 17 as an evaporator, evaporation in the evaporator is performed, the generated water vapor 24 is adsorbed by the adsorbent, and cold heat is generated in the evaporation process of the evaporator. The adsorption heat exchanger for solar driving having the above function is required to operate sufficiently at ambient temperature, and in this regard, the expected effect is large when the molding adsorbent of the present invention using black graphite is used. There is something.

[0030]

As described above, the heat transfer performance can be improved by the structure of the molded adsorbent, and the regeneration heat and the adsorption temperature can be lowered by the structure of the adsorption heat exchanger using the present adhesive. As a result, the cycle refrigerant circulation amount is increased, and the refrigeration capacity can be improved. Also,
The adsorption regeneration cycle time can be reduced, and the heat exchanger can be made more compact. In addition, the efficiency of the adsorption heat exchanger for driving sunlight can be improved by using the adsorbent for molding of the present invention.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of an adsorption heat exchanger formed as an integral structure by immersion molding using the molding adsorbent of the present invention.

FIG. 2 is a perspective view showing a schematic configuration of an adsorption heat exchanger integrally formed by molding using the molding adsorbent of the present invention.

FIG. 3 is a view showing the adsorption characteristics of an adsorption heat exchanger when the molding adsorbent of the present invention is used.

FIG. 4 is a view showing the adsorption characteristics of an adsorption heat exchanger using conventional crushed silica gel.

FIG. 5 is a view showing a schematic configuration of an adsorption heat exchanger for driving sunlight using the adsorbent for molding of the present invention.

FIGS. 6A and 6B are schematic diagrams illustrating an operation state of the solar heat adsorption heat exchanger, in which FIG. 6A illustrates an operation state in daytime and FIG. 6B illustrates an operation state in nighttime.

FIG. 7 is a diagram showing a schematic configuration of a conventional adsorption refrigerator.

FIG. 8 is a diagram showing a schematic configuration of a conventional adsorption heat exchanger.
(A) shows a plate heat conduction type, and (B) shows a pipe and fin heat conduction type.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Heat transfer tube 11 Fin 12 Molding adsorbent layer 13 Groove 14 Immersion adsorbing agent layer 15a, 15b Adsorption heat exchanger of integral structure 16 Adsorption heat exchanger for driving solar light 17 Condenser 20 Molding adsorbent 21 Heat insulation container 22 Solar irradiation space and absorption / desorption space

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masahiro Ito Mizusawa Chemical Industry Co., Ltd. 4-1-1, Nihonbashi Muromachi, Chuo-ku, Tokyo

Claims (4)

[Claims] 1. An adsorbent for an adsorption type refrigerator, wherein silica gel, graphite, an organic binder and an inorganic binder are mixed, water is added and dispersed to form a slurry or paste. . 2. A heat exchanger comprising a heat transfer pipe and heat transfer fins, wherein the adsorbent is immersed in the slurry-form forming adsorbent according to claim 1, air-dried, and then dried at about 70 ° C. to remove the adsorbent. An adsorption heat exchanger having an integrally molded structure characterized by being immersed. 3. A heat exchanger comprising a heat transfer pipe and heat transfer fins, wherein the paste is air-dried with the adsorbent for forming a paste according to claim 1, and then subjected to a mold drying process at about 70 ° C. to perform the adsorption. An adsorption heat exchanger having an integrally molded structure, characterized in that the agent is molded. 4. A molded adsorbent molded and dried into a predetermined shape from the adsorbent for molding according to claim 1, and the adsorbent is housed in a lower portion to form a solar irradiation space and a refrigerant vapor adsorption / desorption space in an upper portion. An adsorption heat exchanger for driving sunlight, comprising a container made of a heat insulating member.