JP2008292061A - Total enthalpy heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a total enthalpy heat exchanger capable of maintaining high efficiency of moisture exchange even in the environment causing dew condensation repeatedly and having high efficiency of total enthalpy heat exchange. <P>SOLUTION: This total enthalpy heat exchanger exchanges heat between sensible heat and latent heat of two air currents through a partition plate by letting two air currents flow across the partition plate. The partition plate is constituted by a gas shutting-out material including a cross-linking component formed by cross-linking polysaccharide derived from sea weeds in an ionic manner by ion cross-linking agent. Preferably, the polysaccharide derived from sea weeds is alginate or carageenan and the ion cross-linking agent is calcium chloride. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention provides total heat used in a ventilation device that simultaneously supplies fresh outside air and exhausts polluted indoor air, an air processing device in an air conditioning machine room such as a building (total heat exchange device between supply air and exhaust), and the like. It relates to an exchanger.

  As a method of performing ventilation without impairing the indoor heating / cooling effect, there is a method of performing ventilation while exchanging heat between supply air and exhaust. In order to improve the efficiency of heat exchange, it is effective to simultaneously exchange temperature (sensible heat) and humidity (latent heat) between supply air and exhaust (that is, to perform total heat exchange). .

Conventionally, a total heat exchanger that performs total heat exchange between air supply and exhaust through a partition plate in which a porous polymer member is impregnated or coated with a hydrophilic polymer containing a hygroscopic agent has been proposed (for example, (See Patent Document 1).
Conventionally, a total heat exchanger that performs total heat exchange between air supply and exhaust through a partition plate in which a water-insoluble hydrophilic polymer thin film is formed on one side of a porous sheet has also been proposed (for example, (See Patent Document 2).
Furthermore, conventionally, it has been proposed to use a water conductive membrane made of a sulfonated statistical styrene copolymer as a partition plate (see, for example, Patent Documents 3 and 4).

JP 60-205193 A JP-A-6-194093 JP-T-2004-504928 JP-T-2004-535270

However, in the total heat exchanger described in Patent Document 1, since the compatibility between the hygroscopic agent and the hydrophilic polymer is not good, the hygroscopic agent is washed away due to condensation that occurs on the surface of the partition plate, and the moisture permeability of the partition plate There was a problem that decreased. Moreover, in the total heat exchanger of patent document 2, there existed a problem that moisture permeability performance was low compared with the case where a partition plate contains a hygroscopic agent. Furthermore, in order to obtain the water conductive membranes described in Patent Documents 3 and 4, it is necessary to use an aryl vinyl monomer such as styrene having high toxicity and strong odor, and also an organic solvent having odor and harmfulness. In order to remove the organic solvent, it is necessary to dry at a high temperature for a long time.
Therefore, the present invention has been made to solve the above problems, and is capable of maintaining high humidity exchange efficiency even in an environment where condensation is repeated, and is a total heat exchanger having high total heat exchange efficiency. The purpose is to provide.

Therefore, as a result of intensive research and development to solve the conventional problems as described above, in order to solve such problems, the present inventors used a seaweed-derived polysaccharide as a partition plate. The inventors have conceived that it is effective to use a gas shielding material containing a crosslinked product ionically crosslinked with an ionic crosslinking agent, and have completed the present invention.
That is, the present invention is a total heat exchanger that causes two kinds of airflows to flow through a partition plate, and exchanges sensible heat and latent heat of the two kinds of airflows via the partition plate, wherein the partition plate Is composed of a gas shielding material containing a crosslinked product obtained by ionically crosslinking a polysaccharide derived from seaweed with an ionic crosslinking agent.

  According to the present invention, it is possible to provide a total heat exchanger having high total heat exchange efficiency while maintaining high humidity exchange efficiency even in an environment where condensation is repeated.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
1 is a perspective view showing a total heat exchanger according to Embodiment 1. FIG. In FIG. 1, the total heat exchanger 1 includes a stacked body in which an air supply layer 2 through which an air flow of supply air passes and an exhaust layer 3 through which an air flow of exhaust passes are alternately stacked via a partition plate 4. It is. The air supply layer 2 is provided with an air supply passage 5 that guides the airflow of the supply air along the partition plate 4. The exhaust layer 3 is provided with an exhaust passage 6 that guides an exhaust airflow along the partition plate 4. The air supply passage 5 and the exhaust passage 6 are respectively formed by corrugated spacing plates 7 that keep the spacing between the partition plates 4. A direction A in which the supply airflow is guided by the supply passage 5 and a direction B in which the exhaust airflow is guided by the exhaust passage 6 are perpendicular to each other.

Each partition plate 4 is composed of a gas-shielding material in which a porous base material contains a cross-linked body obtained by ionically cross-linking a polysaccharide derived from seaweed with an ionic cross-linking agent. Examples of the seaweed-derived polysaccharide include alginic acid and a salt thereof (for example, sodium alginate), carrageenan, fucodyne, and porphyran. Alginate or carrageenan is particularly preferable from the viewpoint of improving condensation resistance. Any ion cross-linking agent may be used as long as it can ionically cross-link seaweed-derived polysaccharides such as sodium alginate and carrageenan to gel these seaweed-derived polysaccharide aqueous solutions. What can ion-crosslink polysaccharides derived from seaweeds such as sodium alginate is a metal ion having a bivalent or higher charge excluding magnesium and mercury, and calcium chloride is particularly preferred from the viewpoint of availability and improved moisture permeability. . The porous substrate is not particularly limited as long as it is a porous substrate, and examples thereof include porous paper, nonwoven fabric, and porous resin film. The higher the basis weight of the porous substrate, the easier it is to manufacture the partition plate 4 having excellent gas shielding properties, but the moisture permeability of the partition plate 4 is lowered and the humidity exchange efficiency tends to be lowered. Therefore, the basis weight of the porous substrate is preferably ^{8g / cm 2 ~30g / cm 2} . Further, the thickness of the porous substrate is preferably 20 μm to 100 μm in consideration of the strength and moisture permeability of the partition plate 4.

  Algonic acid and its salts and ionic cross-linked products of carrageenan have high moisture permeability and do not contain a hygroscopic agent that flows out due to condensation. For this reason, the gas-shielding material in which the crosslinked material is contained in the porous base material does not deteriorate in moisture permeability even under a high humidity atmosphere where condensation occurs. Moreover, since this ion crosslinked body has high water resistance, it does not melt | dissolve by dew condensation etc., and gas-shielding property can be maintained also in a high humidity atmosphere. Furthermore, there is an advantage that it is not necessary to use an organic solvent when the partition plate 4 is manufactured.

From the viewpoint of improving moisture permeability, it is preferable that the amount of the ionically crosslinked body contained in the partition plate 4 as the gas shielding material is smaller. However, if the amount of the ionic crosslinked product is too small, pinholes are likely to be generated, and the gas shielding property may be impaired. In consideration of both moisture permeability and gas shielding properties, the amount of the ion-crosslinked body is preferably 3 g to 30 g per 1 m ² of the partition plate 4 area.

  The corrugated spacing plate 7 is not particularly limited, and known corrugated processed paper or the like can be used. Moreover, the thickness of the space | interval board 7 is not specifically limited, Usually, it sets suitably in the range of 50 micrometers-200 micrometers.

  Next, the operation of the total heat exchanger 1 will be described. For example, when cold and dry outside air is passed through the supply layer 2 as supply air, and warm and humid room air is passed through the exhaust layer 3 as exhaust, each supply air flow and exhaust air flow (two air flows) ) Flows across each partition plate 4. At this time, heat and water vapor pass through the partition plate 4, and heat exchange of sensible heat and latent heat is performed via the partition plates 4 between the supply air and the exhaust air. Thus, the supply air is warmed and humidified and supplied to the room, and the exhaust is cooled and dehumidified and discharged to the outside.

  Next, the manufacturing method of the total heat exchanger 1 is demonstrated. First, a porous substrate impregnated with an ionic crosslinking agent is prepared by immersing the porous substrate in an aqueous solution containing an ionic crosslinking agent and then drying it by heating. The amount of the ionic crosslinking agent impregnated into the porous substrate may be an amount sufficient to gel the aqueous solution of polysaccharide derived from seaweed applied in the subsequent step. Subsequently, after applying an aqueous solution of polysaccharides derived from seaweed to the surface of the porous substrate with a bar coater or the like, a crosslinked product obtained by ionically crosslinking the polysaccharides derived from seaweed with an ionic crosslinking agent is obtained by heating and drying this. A partition plate 4 as a gas shielding material is prepared. For the purpose of removing water-soluble components such as unreacted ionic crosslinking agents and seaweed-derived polysaccharides from the partition plate 4 thus produced, the partition plate 4 may be immersed in water. Thereafter, the partition plate 4 is bonded to the corrugated spacing plate 7 to produce a laminate unit, and a desired number of the laminate units are laminated so that the wave grooves of the spacing plate 7 are alternately orthogonal. Thus, the total heat exchanger 1 is obtained.

[Example 1]
A porous paper having a thickness of 50 μm and a basis weight of 20 g / cm ² was dipped in an aqueous calcium chloride solution and then dried by heating to obtain a porous paper containing 8 g / m ^{2 of} calcium chloride. A 2% by mass aqueous sodium alginate solution was applied to one side of the porous paper containing calcium chloride with a bar coater. The applied sodium alginate aqueous solution immediately gelled, and it was confirmed that calcium alginate which is an ionic cross-linked product was formed. Thereafter, the porous paper is dried by heating, and further immersed in water to remove water-soluble components such as calcium chloride and sodium alginate adhering to the porous paper, and this is dried again by heating, whereby 4 g of calcium alginate is obtained. A partition plate containing / m ² was obtained. Furthermore, this partition plate was bonded to a spacing plate obtained by processing a processed paper having a thickness of 100 μm into a corrugated plate shape, thereby producing a laminate unit. Thereafter, after forming the laminate unit so that the shape of the partition plate is a square of 30 cm square, as shown in FIG. 1, a plurality of laminate units are arranged so that the direction of the wave groove of the spacing plate is alternately orthogonal. Lamination was performed to obtain a total heat exchanger having a height of 50 cm.

[Example 2]
A partition plate containing 4 g / m ^{2 of the} crosslinked calcium ion of ι-carrageenan was obtained in the same manner as in Example 1 except that a 2% by weight ι-carrageenan aqueous solution was used instead of the 2% by weight sodium alginate aqueous solution. . A total heat exchanger was obtained in the same manner as in Example 1 using the obtained partition plate.

[Example 3]
A partition plate containing 4 g / m ^{2 of} a carrageenan calcium ion crosslinked product was obtained in the same manner as in Example 1 except that a 2% by mass κ-carrageenan aqueous solution was used instead of the 2% by mass sodium alginate aqueous solution. A total heat exchanger was obtained in the same manner as in Example 1 using the obtained partition plate.

[Example 4]
A porous paper having a thickness of 50 μm and a basis weight of 20 g / cm ² was immersed in an aluminum sulfate aqueous solution and then dried by heating to obtain a porous paper containing 6 g / m ^{2 of} aluminum sulfate. A partition plate containing 4 g / m ^{2 of} aluminum alginate was obtained in the same manner as in Example 1 except that this porous paper containing aluminum sulfate was used. A total heat exchanger was obtained in the same manner as in Example 1 using the obtained partition plate.

[Comparative Example 1]
A 2% by mass aqueous sodium alginate solution was applied to one side of a porous paper (not impregnated with calcium chloride) having a thickness of 50 μm and a basis weight of 20 g / cm ² with a bar coater. Thereafter, this porous paper was dried by heating to obtain a partition plate containing 4 g / m ^{2 of} sodium alginate. A total heat exchanger was obtained in the same manner as in Example 1 using the obtained partition plate.

[Comparative Example 2]
By repeating the application of the sodium alginate aqueous solution and the heat drying in Comparative Example 1 several times, a partition plate containing 24 g / m ^{2 of} sodium alginate was obtained. A total heat exchanger was obtained in the same manner as in Example 1 using the obtained partition plate.

[Comparative Example 3]
A partition plate containing 4 g / m ^{2 of} ι-carrageenan was obtained in the same manner as in Comparative Example 1 except that a 2% by weight ι-carrageenan aqueous solution was used instead of the 2% by weight sodium alginate aqueous solution. A total heat exchanger was obtained in the same manner as in Example 1 using the obtained partition plate.

[Comparative Example 4]
A partition plate containing 4 g / m ² of a calcium ion crosslinked product of carboxymethyl cellulose was obtained in the same manner as in Example 1 except that a 2% by mass carboxymethyl cellulose aqueous solution was used instead of the 2% by mass sodium alginate aqueous solution. A total heat exchanger was obtained in the same manner as in Example 1 using the obtained partition plate.

[Comparative Example 5]
A partition plate containing 4 g / m ^{2 of} polystyrene sulfonate was obtained in the same manner as in Example 1 except that a 2% by weight sodium polystyrene sulfonate aqueous solution was used instead of the 2% by weight sodium alginate aqueous solution. A total heat exchanger was obtained in the same manner as in Example 1 using the obtained partition plate.

[Comparative Example 6]
By using 20% by weight polystyrene sodium sulfonate aqueous solution instead of 2% by weight polystyrene sodium sulfonate aqueous solution in Comparative Example 5 and repeating the application of the sodium polystyrene sulfonate aqueous solution and heat drying several times, A partition plate containing 63 g / m ² was obtained. A total heat exchanger was obtained in the same manner as in Example 1 using the obtained partition plate.

[Comparative Example 7]
A total heat exchanger was obtained in the same manner as in Example 1 using a partition plate made of non-porous paper having a thickness of 30 μm and containing 2 g / m ^{2 of} calcium chloride.

<Performance evaluation of total heat exchanger>
The performance of each total heat exchanger of Examples 1-4 and Comparative Examples 1-7 was evaluated.
The exchange efficiency and the carbon dioxide transfer rate of the total heat exchanger were carried out in accordance with JIS B8628. The air condition is a primary airflow (supply air) at a temperature of 27 ° C., a relative humidity of 52.7% RH, and a secondary airflow (exhaust) of a temperature of 35 ° C. and a relative humidity of 64.3% RH (cooling conditions).
After the above measurement, after immersing each total heat exchanger in normal temperature water for 1 hour and then heating and drying at 80 ° C. 5 times to simulate the dew condensation state, the exchange efficiency and dioxide dioxide were tested under the same test conditions as above. The carbon transfer rate was measured again. In addition, the evaluation of the carbon dioxide migration rate (before and after the dew condensation test) is less than 5% for good gas shielding (○), and 5% or more for poor gas shielding (×). did. In the evaluation of the humidity exchange efficiency after the dew condensation test, the humidity exchange efficiency decrease is less than 10% before and after the dew condensation test (○), and the humidity exchange efficiency decrease is 10% or more before and after the dew condensation test. Was inferior (x).
These results are shown in Table 1.

  From the above results, the temperature exchange efficiency is 78% in both the examples and the comparative examples, but the total heat exchangers of Examples 1 to 4 have high humidity exchange efficiency and total heat exchange efficiency, and It was found that the carbon transfer rate was small. Furthermore, the total heat exchangers of Examples 1 to 4 maintained the humidity exchange efficiency and the carbon dioxide transfer rate even after the dew condensation test. Since calcium chloride is an inorganic salt having deliquescence, it shows high moisture permeability just by being contained in non-porous paper as in Comparative Example 7. In Examples 1 to 3, if the step of immersing in water after ion-crosslinking a polysaccharide derived from seaweed is omitted, calcium chloride remains on the partition plate. In that case, the initial humidity exchange efficiency is further higher than that in water. This is why calcium chloride is particularly preferred. However, the humidity exchange efficiency is equivalent to those of Examples 1 to 3 because calcium chloride is gradually washed away from the partition plate due to condensation or the like.

  In Comparative Examples 1 and 5, the initial carbon dioxide transfer rate increased. This means that holes such as pin holes are formed in the partition plate and the gas shielding property of the partition plate is impaired, and as a result, the air on the supply side and the exhaust side of the total heat exchanger are mixed. Such a state is defective as a total heat exchanger, and accurate exchange efficiency cannot be measured. Therefore, in Comparative Examples 1 and 5, the exchange efficiency is not measured.

  From the results of Examples 1 and 2, after impregnating the porous paper with calcium chloride, the calcium ion crosslinked product of calcium alginate or ι-carrageenan gelled by simply applying a small amount of sodium alginate or ι-carrageenan aqueous solution. It is understood that the gas shielding property of the partition plate is secured.

In contrast, Comparative Example 2 in which the amount of sodium alginate was increased as compared with Comparative Example 1 was able to suppress the initial carbon dioxide transfer rate to less than 5%, but the amount of sodium alginate contained in the partition plate increased. As a result, the moisture permeability of the partition plate was lowered and the humidity exchange efficiency was lowered. Moreover, since sodium alginate itself is water-soluble, the carbon dioxide transfer rate was increased by the dew condensation test, and the gas shielding property of the partition plate was impaired.
Further, in Comparative Example 3 in which an aqueous solution of ι-carrageenan was applied to porous paper without impregnation with calcium chloride and dried by heating, the initial carbon dioxide transfer rate could be suppressed to less than 5%, but the dew condensation test After that, the carbon dioxide transfer rate increased, and the gas shielding property of the partition plate was impaired.

  Comparative Example 4 is an example using a calcium ion crosslinked product of carboxymethyl cellulose. Carboxymethylcellulose is a polysaccharide derived from cellulose. In Comparative Example 4, although the carbon dioxide transfer rate was maintained before and after the dew condensation test, the humidity exchange efficiency was low.

  Comparative Examples 5 and 6 are examples in which calcium polystyrene sulfonate was formed on a porous paper. In Comparative Example 5, the initial carbon dioxide transfer rate increased. This is presumably because when the aqueous polystyrene sulfonate solution and calcium chloride are mixed, the aqueous solution does not gel, and calcium polystyrene sulfonate precipitates. In Comparative Example 6 in which the coating amount of polystyrene sulfonate calcium was increased as compared with Comparative Example 5, the initial carbon dioxide migration rate was maintained, the moisture permeability was small, and the carbon dioxide migration rate was large after the condensation test.

  The comparative example 7 uses the partition plate which made the non-porous paper contain calcium chloride. In Comparative Example 7, the initial exchange efficiency and the carbon dioxide transfer rate were comparable to those of Examples 1 to 4, but the humidity exchange efficiency was greatly reduced by the dew condensation test. This is because the humidity exchange efficiency of the partition plate depends on calcium chloride, and it is considered that the humidity exchange efficiency was greatly reduced because calcium chloride was washed away in the dew condensation test.

1 is a perspective view showing a total heat exchanger according to Embodiment 1. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Total heat exchanger, 2 Supply layer, 3 Exhaust layer, 4 Partition plate, 5 Supply path, 6 Exhaust path, 7 Space plate

Claims (3)

A total heat exchanger for flowing two kinds of airflows across the partition plate, and exchanging heat between sensible heat and latent heat of the two kinds of airflows via the partition plate,
The total heat exchanger, wherein the partition plate is composed of a gas shielding material including a crosslinked body obtained by ionically crosslinking a seaweed-derived polysaccharide with an ionic crosslinking agent.   The total heat exchanger according to claim 1, wherein the seaweed-derived polysaccharide is alginate or carrageenan.   The total heat exchanger according to claim 1, wherein the ionic crosslinking agent is calcium chloride.

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