Patent Application
20070095513
1. Field of the Invention
The present invention relates to a total heat exchanger which exchanges sensible heat and latent heat, and, more particularly, to improvement in a latent heat exchanging efficiency.
2. Description of the Related Art
A known total heat exchanger is described below.
This heat exchanger, which is of a honeycomb structure, is formed by stacking a corrugated substrate, which serves as a space retaining plate, and a flat substrate, which serves as a partition plate. The corrugated and flat substrates are constructed of an artificial paper including cellulose fibers and thermoplastic fibers, and are bonded with the thermoplastic fibers by performing heating and pressurizing treatments, which also provides rigidity (see, for example, Japanese Unexamined Utility Model Registration Application Publication No. 56-93694 (pages 1 to 4,
A known heat exchanger has, during the exchange of latent heat, a lower rate of blocking the movement of moisture through a joint,. that is, has less of a reduction in an effective moisture permeable area as compared to a joint bonded with a moisture impermeable adhesive because the corrugated and flat substrates are bonded with the thermoplastic fibers by performing heating and pressurizing treatments. However, the known heat exchanger has an insufficient moisture permeability because both the flat substrate, which serves as a partition, and the corrugated substrate, which serves as a space retaining plate, themselves have a poor moisture permeability.
Referring now to the air conditions in summer and winter for the total heat exchanger (cited from JIS B 8628 air conditions for a total heat exchanger), it is shown that, in summer, an outdoor air temperature and a relative humidity are 35°° C. and 64.4% RH respectively, and a room temperature and a relative humidity are 27° C. and 52.4% RH respectively and, in winter, an outdoor air temperature and a relative humidity are 5° C. and 57.8% RH respectively, and a room temperature and a relative humidity are 20° C. and 51.1% RH respectively. That is to say, under the summer and winter air conditions, the energy proportion of humidity (latent heat) to a total heat is about 50%. Particularly, the energy proportion of latent heat of a room in summer accounts for two-thirds. Therefore, a latent heat exchanging efficiency is important. Furthermore when the humidity becomes higher in summer, the proportion of the latent heat becomes larger, and thus, the latent heat exchanging efficiency is of greater importance.
Recently, there has also been a need for further improvement in heat exchanging efficiency of the total heat exchanger. For further improvement in heat exchanging efficiency, improvement in the latent heat exchanging efficiency is particularly important as described above. However, the known heat exchanger still has the above problems.
The present invention was contemplated taking into consideration the problems described above. It is an object of the present invention to achieve further improvement in the latent heat exchanging efficiency of the heat exchanger to provide a further improvement in heat exchanging efficiency. The heat exchanger according to the present invention, in which two types of air flows are directed across moisture permeable partition plates which are spaced apart by space retaining plates, where heat exchange is performed between the air flows through the partition plate, has joints formed by bonding the partition plate and the space retaining plate with a fluoro resin or a hydrocarbon resin having an excellent moisture absorption and diffusion property that is provided by a hydrophilic group contained therein.
In these drawings, a heat exchanger 1 is of a hexahedron structure which is formed by stacking, in multiple layers, in such a manner that the opening directions (air flow direction) of passageways having a wave shape in the cross section thereof intersect with each other every other layer at an angle of substantially 90 degrees, a plurality of the unit constructional elements (shown in
The partition plate 2 and the space retaining plate 3 are porous members, and are preferably formed by mixing, for example, resin fibers with cellulose fibers and by mixing a binder in the resins. Alternatively, nonwoven fabrics of polyolefin, including polyethylene, polypropylene, polyethylene terephthalate and the like, and of polyester, metallic fibers, or glass fibers may be used to construct the partition plate 2 and the space retaining plate 3.
Also, the partition plate 2 may be coated with a moisture permeable film layer having an air shielding property on the surface thereof in order to have an air shielding property.
The partition plate 2 and the space retaining plate 3 are joined by bonding the top portion of the wave shape of the space retaining plate 3 to the partition plate 2 with an adhesive 8 as illustrated by the unit constructional element shown in
The material of the adhesive 8 is composed of resins containing a hydrophilic group which provide an excellent moisture absorption and diffusion property to an adhesive layer 8a which serves as a joint layer 8a after joining and hardening, for example, perfluoro-sulfonic acid resin (a perfluoro-sulfonic acid ion exchange resin, i.e., fluoro ion exchange resin having a sulfonic acid group serving as a hydrophilic group) which is used for an electrolyte membrane of a proton-exchange electrolyte membrane fuel cell (PEFC).
The perfluoro-sulfonic acid resin has an excellent moisture absorption and diffusion property, i.e., excellent moisture permeability, and durability, and, in addition, an antimicrobial property due to the acid.
In addition to the perfluoro-sulfonic acid resin, a macromolecular copolymer which is partially sulfonized, i.e., a hydrocarbon resin having hydrophilic groups (a hydrocarbon ion exchange resin), may be used as a resin having an excellent moisture absorption and diffusion property. For example, a copolymer of an allyl-vinyl monomer and an olefin monomer which has an average molecular weight of about 20000 and in which an aromatic hydrocarbon bonded with an allyl-vinyl monomer is partially sulfonized is available. Now as an allyl-vinyl monomer, which accounts for 20 to 80 wt % of the total weight, styrene, vinyl-toluene, and a-methyl toluene will be discussed, the styrene there among being most suitable. Preferably, a styrene sulfonic acid accounts for 30 to 50 mol % of the aromatic hydrocarbon which bonds with the allyl-vinyl monomer. Ethylene is most suitable for the olefin monomer. That is, styrene ethylene copolymer resin (ion exchange resin), which has a molecular weight of about 20000 and is partially sulfonized, is recommended.
The hydrocarbon resin (hydrocarbon ion exchange resin) which is sulfonized to have a hydrophilic group has a high level of the moisture absorption and diffusion property, i.e., a high level of the moisture permeability, is relatively less expensive, and also has an antimicrobial property.
For using these resins as the adhesive 8 they are softened by heat, emulsified, or dispersed in solvents including alcohol or acetone before use.
The heat exchanger 1 which is formed in a manner described above is used in an air conditioning machine and performs total heat exchange without mixing between adjacent air flows across the partition plate 2 because, as shown in
That is, the heat exchanger 1 performs total heat exchange between the exhaust air which is discharged from a room and the supply air which is introduced into a room during the introduction of fresh air from the outdoors into the room so as to make the temperature and humidity properties of the supply air close to those of the room air.
Also, the use of the adhesive 8 described above enables absorption and movement of moisture from the joint 8a, i.e., the adhesive layer 8a to the partition plate 2 that have been disabled because of the adhesive which has no moisture permeability has been conventionally used, which clogged up pores of the partition plate 2 during corrugating and stacking processes. This results in an increase in the effective moisture permeable area of the partition plate 2 as compared to the joint formed by the adhesive which has no moisture permeability as shown in
An illustrative example of an increase in the effective moisture permeable area is described with reference to
As shown in
(P−d)2/P2=0.6
The use of the adhesive 8 according to the present embodiment makes an entire area including the joint 8a moisture-permeable so as to increase the ratio of the effective moisture permeable area to the total area from 0.6 to 1.0.
In addition to the increase in the effective moisture permeable area of the partition plate 2 as described above, the heat exchanger 1 uses a resin having a higher level of the moisture absorption and diffusion property as the adhesive 8 so that a larger quantity of moisture is allowed to be absorbed, diffused and penetrate the partition plate 2 through the joint 8a as compared to the joint which is described in the related art because the joint 8a can serve as a moisture absorbing and diffusing layer. That is, a larger quantity of moisture can penetrate the partition plate 2. This results in a substantially further increased effective moisture permeable area so as to enable a larger quantity of moisture to be given to the air flows which pass through the longitudinally-adjacent fluid passageways. Therefore, further improvement in the latent heat exchanging efficiency of the heat exchanger 1 can be achieved (refer to
An oval shown in
In the present embodiment, when the heat exchanger constructional elements 6 cut out are stacked in such a way that the wave divisions of adjoining space retaining member plates 3 extend in parallel, a countercurrent type heat exchanger 1 can be constructed.
The adhesive 8 is used to bond the top of the space retaining plate 3 of the heat exchanger 1 according to the present embodiment to the partition plate 2 in the same way as that of the embodiment 1. During this process, the adhesive 8 is provided to the circumference of the top in addition to the joint 8a of the space retaining plate 3. The moisture absorbing and diffusing layer is formed by, for example, applying the adhesive layer 8a, i.e., the adhesive 8, continuously around the joint 8a on the surface of the space retaining plate 3 in a proportion of 30 to 50% of the surface area of the space retaining plate 3. That is to say, according to the present embodiment, as shown in
The technique described above allows the moisture absorbing and diffusing layer of the space retaining plate 3 which is formed adjacently to the joint 8a with the partition plate 2 to have a higher level of the moisture absorption and diffusion property in addition to the joint 8a so that the moisture absorbing area is increased. Thus, the moisture of the air flows which pass through the fluid passageways is absorbed by the moisture absorbing and diffusing layer of the space retaining plate 3, diffused therein, and penetrates the partition plate 2 through the joint 8a between the partition plate 2 and the space retaining plate 3 to moisten the adjacent dry air flows. In particular, the moisture absorbing and diffusing layer has a higher level of the moisture absorption and diffusion property to absorb and diffuse a larger quantity of the moisture.
Thus, the moisture permeability of the partition plate 2 is improved, that is, the substantially effective moisture permeable area of the partition plate 2 is increased so that the moisture exchanging efficiency (latent heat exchanging efficiency) is improved. This leads to a further improvement in the heat exchanging efficiency.
In the related art, the cross-sectional shape of the space retaining plate 3 which is bonded to the partition plate 2 has been formed in triangles as acute as possible to minimize the width (corresponds to the area of the joint) of the joint 8a. However, the high speed manufacturing by a corrugating machine and the like causes ridge cracks, which means a break with cracks formed in the space retaining plate 3, to occur, thus, the manufacturing speed must be reduced. As a result, the workability has been degraded.
The present embodiment permits workers not to pay attention to a quantity of the attached adhesive 8 and the resulting width because the joint 8a has a high level of the moisture absorption and diffusion property. Therefore, as the space retaining plate 3, a corrugated plate which has stages of a rounded shape called a UV or U stage which provides a high workability is permitted to be manufactured and used. This results in an improvement in the manufacturing speed at which the unit constructional elements 4 are manufactured by the corrugating machine, and leads to an improvement in workability.
The corrugated stage with a rounded stage shape called the UV or U stage makes it easier, due to the rounded shape thereof, to attach a large quantity of the adhesive 8 as compared to the conventional stage shape. This corrugated stage is advantageous because it is preferred to attach the adhesive 8 in a quantity as large as possible to the space retaining plate 3.
A stacking process was actually carried out by using U-shaped corrugated stages. As a result, the adhesive could be attached to about 30 to 50% of the side area of the space retaining plate 3. This means that about three times of the related art minimum necessary quantity of the adhesive 8 (bonding agent 8) can be achieved.
That is, it has been assumed that the impermeable adhesive 8 conventionally provides the effective moisture permeable area which accounts for about 60% of the side area of the space retaining plate. The present embodiment has successfully achieved the moisture exchanging efficiency which is equivalent to that obtained when the effective moisture permeable area corresponding to substantially about 110% of the side area of the space retaining plate is achieved. That is, the substantial expansion of the effective moisture permeable area has been achieved.
As shown in
Also, in the heat exchanger 1 according to the present embodiment, improvement in the mechanical strength of fragile materials, including paper possibly used as a porous material for the space retaining plate 3, is achieved by coating and allows them to be used for the space retaining plate 3.
The heat exchanger 1 shown in
The coatings described above increase the substantially effective moisture permeable area so that the moisture absorbing performance of the partition plate 2 is improved due to formation of the moisture absorbing and diffusing layer having a high level of the moisture absorption and diffusion property. This results in an increase in the quantity of the moisture which penetrates the partition plate 2. Thus, the moisture exchanging efficiency (latent heat exchanging efficiency) can be dramatically improved.
The formation of the moisture absorbing and diffusing layer only around the joint 8a on the space retaining plate 3, as shown in
Moreover, the formation of the moisture absorbing and diffusing layer on the surface of the partition plate 2 only can provide an increase in the substantially effective moisture permeable area so that the quantity of the moisture which penetrates the partition plate 2 can be increased instead of the formation of the layer on the surfaces of both partition plate 2 and the space retaining plate 3. This leads to an achievement of the improvement in the moisture exchanging efficiency (latent heat exchanging efficiency).
The heat exchanger 1 shown in
This way allows the space retaining plate 3 by itself to serve as a moisture absorbing and moving medium. Therefore, an increase in the substantially effective moisture permeable area of the partition plate depending on the increase in the moisture permeable area makes possible a dramatic improvement in the moisture exchanging efficiency (latent heat exchanging efficiency).
In this way, as shown in
Also, as shown in
This way also makes it possible to dramatically improve the moisture exchanging efficiency (latent heat exchanging efficiency).
The heat exchanger according to the present invention, in which two types of air flows are directed across a moisture permeable partition plate spaced apart from an adjacent partition plate by a space retaining plate, where heat exchange is performed through the partition plate between the two types of the air flows, has a joint which is formed between the partition plate and the space retaining plate by bonding them using fluoro-resins or hydrocarbon resins which contain a hydrophilic group which provides a high level of the moisture absorption and diffusion property so as to achieve an increased substantially effective moisture permeable area, an improvement in the moisture exchanging efficiency (latent heat exchanging efficiency), and a further improvement in the heat exchanging efficiency.
