HEAT EXCHANGER, CHEMICAL HEAT PUMP, AND PRODUCTION METHOD FOR PRODUCING HEAT EXCHANGER

- Ricoh Company, Ltd.

A heat exchanger includes a plurality of plate fins including a plurality of flow channels in which a heat medium flows; a plurality of corrugated fins, the plurality of plate fins and the plurality of corrugated fins being arranged alternately; and a reaction portion solidified by crystallization of reaction material slurry filling gaps between the plurality of plate fins and the plurality of the corrugated fins, the reaction material slurry including a reaction material that reversibly reacts with a reaction medium in an exothermic manner and in an endothermic manner to exchange heat with the heat medium.

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Description
BACKGROUND OF THE INVENTION

1. Field of the Invention

The disclosures herein generally relate to a heat exchanger, a chemical heat pump and a production method for producing a heat exchanger.

2. Description of the Related Art

In recent years, from the standpoint of energy conservation, heat recovery systems such as chemical heat pumps that effectively employ excessive exhaust heat are attracting attention.

Chemical heat pumps are systems that conduct supplying of heat and accumulation (storage) of heat using an exothermic phenomenon and an endothermic phenomenon accompanying a reversible chemical reaction occurring between a reaction medium and a heat accumulation material (hereinafter referred to as “reaction material”). Typically, the chemical heat pump includes a heat exchanger that exchanges heat with a heat medium. The heat exchanger houses a reaction material that reacts with a reaction medium in an exothermic manner and in an endothermic manner.

In order to improve usage efficiency of the exothermic reaction and the endothermic reaction in the heat exchanger, Japanese Unexamined Patent Application Publication No. H11-108499 discloses a configuration in which a plurality of plate fins and a plurality of corrugated fins are layered and granulated adsorbent materials fill space portions formed between the plate fins and the corrugated fins. Further, Japanese Unexamined Patent Application Publication No. H10-103811 discloses a configuration in which an adsorbing portion, in which a plurality of adsorbing materials are integrated with a binder, is formed between heat transmission tubes and corrugated fins.

However, in the configuration disclosed in Japanese Unexamined Patent Application Publication No. H11-108499, contact areas of the granulated adsorbent materials with the plate fins and the corrugated fins are small. Thus, there is a likelihood that reaction heat generated in the adsorbent materials is not effectively exchanged with the heat medium via the plate fins and the corrugated fins. Further, in the configuration disclosed in Japanese Unexamined Patent Application Publication No. H10-103811, there is a likelihood that the binder, used for integrating the adsorbing materials, inhibits the exothermic reaction and the endothermic reaction and an amount of reaction heat is decreased.

SUMMARY OF THE INVENTION

It is a general object of at least one embodiment of the present invention to provide a heat exchanger, a chemical heat pump and a production method for producing a heat exchanger that substantially obviate one or more problems caused by the limitations and disadvantages of the related art.

An embodiment provides a heat exchanger including a plurality of plate fins including a plurality of flow channels in which a heat medium flows; a plurality of corrugated fins, the plurality of plate fins and the plurality of corrugated fins being arranged alternately; and a reaction portion solidified by crystallization of reaction material slurry filling gaps between the plurality of plate fins and the plurality of the corrugated fins, the reaction material slurry including a reaction material that reversibly reacts with a reaction medium in an exothermic manner and in an endothermic manner to exchange heat with the heat medium.

An embodiment also provides a production method for producing a heat exchanger in which a plurality of plate fins including a plurality of flow channels where a heat medium flows and a plurality of corrugated fins are arranged alternately. The production method includes a slurry making step of making reaction material slurry including a reaction material that reversibly reacts with a reaction medium in an exothermic manner and in an endothermic manner to exchange heat with the heat medium; a filling step of filling gaps between the plurality of plate fins and the plurality of corrugated fins with the reaction material slurry; and a reaction portion forming step of forming a reaction portion by solidifying the reaction material slurry filling the gaps between the plurality of plate fins and the plurality of corrugated fins.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic drawing illustrating an example of an overall configuration of a chemical heat pump according to an embodiment;

FIG. 2 is a drawing that depicts heat accumulation operation of the chemical heat pump;

FIG. 3 is a drawing that depicts heat radiation operation of the chemical heat pump;

FIG. 4 is a drawing illustrating an example of a configuration of a heat exchanger according to the embodiment;

FIG. 5 is a drawing illustrating another configuration example of the heat exchanger according to the embodiment;

FIG. 6 is a flowchart illustrating an example of a production method for producing the heat exchanger according to the embodiment;

FIG. 7 is a graph illustrating heat radiation characteristics in a practical example 1;

FIG. 8 is a graph illustrating heat radiation characteristics in a practical example 2;

FIG. 9 is a graph illustrating heat radiation characteristics in a practical example 3;

FIG. 10 is a graph illustrating heat radiation characteristics in a practical example 4;

FIG. 11 is a graph illustrating heat radiation characteristics in a practical example 5;

FIG. 12 is a graph illustrating heat radiation characteristics in a practical example 6;

FIG. 13 is a graph illustrating heat accumulation characteristics in a practical example 7 and a practical example 8; and

FIG. 14 is a graph illustrating heat radiation characteristics in the practical example 7 and the practical example 8.

 DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, an embodiment of the present invention will be described with reference to the accompanying drawings.

<Configuration and Operation of Chemical Heat Pump 10>

FIG. 1 is a schematic drawing illustrating an example of an overall configuration of a chemical heat pump 10 according to an embodiment.

As shown in FIG. 1, the chemical heat pump 10 includes a reactor 100, a condenser 200, and an evaporator 300.

The reactor 100 includes a heat exchanger 110 within a body of the reactor 100. The heat exchanger 110 houses a reaction material that reversibly reacts with a reaction medium in an exothermic manner and in an endothermic manner. A heat medium is introduced (provided) to the heat exchanger 110 from a heat medium introduction port 111. The heat medium introduced into the heat exchanger 110 is discharged from a heat medium discharging port 112 through flow channels of the inside of the heat exchanger 110. For example, the heat medium may be oil such as silicone oil.

The heat exchanger 110 houses the reaction material that reacts with the reaction medium in an exothermic manner and in an endothermic manner, to emit (transfer) heat to the heat medium by the reaction material reacting with the reaction medium in the exothermic manner, and to accumulate (store) heat of the heat medium by the reaction material reacting with the reaction medium in the endothermic manner.

Materials being able to reversibly react with the reaction medium in the exothermic manner and in the endothermic manner such as calcium oxide (CaO), magnesium oxide (MgO), and calcium sulfate (CaSO4) can be used as the reaction material housed in the heat exchanger 110. In the embodiment, gypsum (calcium sulfate (CaSO4)) is used as the reaction material. In a case in which the reaction material is gypsum, an endothermic reaction and an exothermic reaction expressed by the following formula (1) occur using water (H2O) as the reaction medium.


CaSO4+0.5H20(gas)CaSO4.0.5H20+32.89 kJ/mol   (1)

When a reaction to a right direction in the formula (1) occurs, the reaction material radiates (transfers) heat to the heat medium in the heat exchanger 110, and the heat medium, whose temperature is raised, is discharged from the heat exchanger 110. Further, when a reaction to a left direction in the formula (1) occurs, the reaction material accumulates heat transferred from the heat medium in the heat exchanger 110, and the heat medium, whose temperature is lowered, is discharged from the heat exchanger 110.

The condenser 200 is an example of a reaction medium recovery unit, and includes a low temperature heat source 210 inside thereof. The condenser 200 is connected to the reactor 100 via a first connection pipe 11 and a first valve 21. The condenser 200 recovers water vapor from the reactor 100 generated by the endothermic reaction when accumulating heat.

When the operation for accumulating heat in the chemical heat pump 10 is performed, the endothermic reaction to the left direction in the formula (1) proceeds, and water vapor is generated from a hydrate of the reaction material. When such the operation for accumulating heat is performed, as shown in FIG. 2, the first valve 21 is opened and the condenser 200 recovers water vapor from the reactor 100 through the first connection pipe 11. The water vapor recovered by the condenser 200 is cooled and liquefied by the low temperature heat source 210.

The low temperature heat source 210 includes, for example, a pipe, in which low temperature fluid such as water flows, and a plurality of fins arranged around the pipe. The low temperature heat source 210 cools and liquefies water vapor recovered from the reactor 100.

Further, the condenser 200 is connected to the evaporator 300 via a third connection pipe 13 and a third valve 23. By opening the third valve 23 as appropriate, liquefied water is supplied to the evaporator 300 through the third connection pipe 13.

The evaporator 300 is an example of a reaction medium supplying unit, and includes a high temperature heat source 310 inside thereof. The evaporator 300 is connected to the reactor 100 via a second connection pipe 12 and a second valve 22. The evaporator 300 supplies water vapor that is the reaction medium to the reactor 100.

In the evaporator 300, water retained inside is heated by the high temperature heat source 310, and becomes water vapor. When the operation for radiating heat in the chemical heat pump 10 is performed, as shown in FIG. 3, the second valve 22 is opened and water vapor generated in the evaporator 300 is supplied to the reactor 100 through the second connection pipe 12. When the water vapor is supplied to the inside of the reactor 100, the exothermic reaction to the right direction in the formula (1) proceeds, and the reaction material radiates (transfers) heat to the heat medium.

The high temperature heat source 310 includes, for example, a pipe in which high temperature fluid such as water flows and a plurality of fins arranged around the pipe. The high temperature heat source 310 heats water retained in the evaporator 300 to generate water vapor.

The chemical heat pump 10, which has the above described configuration, operates such that the reaction material, housed in the heat exchanger 110, reacts with the reaction medium in the endothermic manner to accumulate heat of the heat medium, and the reaction material reacts with the reaction medium in the exothermic manner to radiate heat to the heat medium.

It should be noted that the reactor 100 may include a plurality of the heat exchangers 110. Further, the condenser 200 and the evaporator 300 are not limited to the above described configurations as long as the reaction medium can be supplied and recovered between the reactor 100, and the condenser 200 and the evaporator 300.

<Configuration of Heat Exchanger 110>

FIG. 4 is a drawing illustrating an example of a configuration of the heat exchanger 110 according to the embodiment.

As shown in FIG. 4, the heat exchanger 110 includes the heat medium introduction port 111, the heat medium discharging port 112, and an introduction tank 113, a discharging tank 114, a plurality of plate fins 115, a plurality of corrugated fins 116, and a reaction portion 117.

In the heat exchanger 110, the introduction tank 113 and the discharging tank 114 are disposed opposite with each other. The plate fins 115 and the corrugated fins 116 are layered (arranged) alternately between the introduction tank 113 and the discharging tank 114. The reaction portion 117 is formed on gaps between the plate fins 115 and the corrugated fins 116. For example, the introduction tank 113, the discharging tank 114, the plate fins 115 and the corrugated fins 116 may be formed of a metallic material such as an aluminum alloy.

The introduction tank 113 and the discharging tank 114 have hollow box shapes, respectively. Each of the plate fins 115 includes a flow channel for the heat medium inside thereof. One end of each of the flow channels of the plate fins 115 is in communication with an inside space of the introduction tank 113 and the other end of each of the flow channels of the plate fins 115 is in communication with an inside space of the discharging tank 114. The heat medium introduced from the heat medium introduction port 111 to the introduction tank 113 flows through the flow channels of the plate fins 115, and is discharged from the heat medium discharging port 112 provided on the discharging tank 114.

Each of the corrugated fins 116 having a continuous wavy shape, in which a plate shaped member is bent, is disposed between the plate fins 115. Each of the corrugated fins 116 contacts both two plate fins 115 (the plate fin 115, which is provided on the upper side of the corrugated fins 116, and the plate fin 115, which is provided on the lower side of the corrugated fins 116) that sandwich the corrugated fin 116 in a vertical direction shown in FIG. 4 such that heat generated in the reaction portion 117 is transferred to the heat medium that flows in the flow channels of the plate fins 115.

The reaction portion 117 is formed by solidification of reaction material slurry, which includes the reaction material that reversibly reacts with the reaction medium in an exothermic manner and in an endothermic manner to exchange heat with the heat medium flowing in the plate fins 115, filling the gaps between the plate fins 115 and the corrugated fins 116.

As described above, the reaction portion 117 is integrally formed with the plate fins 115 and the corrugated fins 116 by the solidification of the reaction material slurry that fills in the gaps between the plate fins 115 and the corrugated fins 116. In this way, by forming the reaction portion 117, the plate fins 115, and the corrugated fins 116 integrally, heat generated by the exothermic reaction and the endothermic reaction between the reaction material and the reaction medium in the reaction portion 117 is easily transferred to the heat medium that flows in the plate fins 115. Thus, usage efficiency of the exothermic reaction and the endothermic reaction by the reaction material in the heat exchanger 110 can be improved.

Here, it is preferable to use gypsum (calcium sulfate (CaSO4)), which can be the (slurried) reaction material slurry by being mixed with water, can fill the gaps between the plate fins 115 and the corrugated fins 116 and can be solidified, as the reaction material used for the reaction portion 117.

Gypsum is classified into anhydrous gypsum (CaSO4), hemihydrate gypsum (CaSO4.0.5H2O), and gypsum dihydrate (CaSO4.2H2O). Further, anhydrous gypsum is classified into type I, type II, and type III depending on difference of a crystal system. In a case in which gypsum is used as the reaction material, the exothermic reaction to the right direction in the formula (1) occurs when type III anhydrous gypsum is hydrated and a phase transition to hemihydrate gypsum occurs, and the endothermic reaction to the left direction in the formula (1) occurs when hemihydrate gypsum is dehydrated and a phase transition to type III anhydrous gypsum occurs.

Hemihydrate gypsum has coagulable and hardenable characteristics by a hydration reaction. Specifically, when hemihydrate gypsum takes water into the crystals and a phase transition to gypsum dihydrate occurs, gypsum slurry (reaction material slurry) in which powder of hemihydrate gypsum and water are combined is coagulated and solidified. Gypsum dihydrate becomes type III anhydrous gypsum, for example, by burning it at about 150 degrees Celsius in a state in which the gypsum slurry is solidified.

Here, because the phase transition from hemihydrate gypsum to gypsum dihydrate occurs in the gypsum slurry, in which hemihydrate gypsum and water are combined, in a short time and the gypsum slurry becomes coagulated and hardened, there is a likelihood that the gypsum slurry is solidified in the middle of filling the gaps between the plate fins 115 and the corrugated fins 116. In order to make it easy to fill the gaps with the gypsum slurry, which is to be coagulated in a short time, it can be considered to enlarge the gaps between the plate fins 115 and the corrugated fins 116. However, it is not preferable to enlarge the gaps between the plate fins 115 and the corrugated fins 116 because the smaller the gaps are, the higher heat exchanging efficiency between the reaction portion 117 and the heat medium is.

Thus, in order to delay the coagulation and the hardening of the gypsum slurry, a setting retarder may be added to the gypsum slurry. Using the setting retarder, a speed of taking water into the crystals of hemihydrate gypsum is decreased and a time required for coagulating and solidifying is prolonged. Thus, it becomes easy to fill the gaps between the plate fins 115 and the corrugated fins 116 with the gypsum slurry.

For example, organic matter such funori glue (Endocladiaceae), Chondrus, gum Arabic, gelatin and starch, inorganic salt such as boracic acid and sodium phosphate, and organic acid such as tartaric acid, citric acid, and succinic acid and its alkali salt can be used as the setting retarder.

Further, a plurality of holes may be provided on the reaction portion 117. FIG. 5 is a drawing illustrating an example of the heat exchanger 110 in which holes 118 are formed on the reaction portion 117.

The holes 118 shown in FIG. 5 are elongated through holes extending in an opposing direction of the introduction tank 113 and the discharging tank 114. For example, the hole 118 can be formed, in a state in which a plate shaped member is inserted into a cut portion formed on the corrugated fin 116, by extracting the plate shaped member after the reaction material slurry has filled the gaps between the plate fin 115 and the corrugated fin 116 and solidified.

By providing the plurality of holes 118 on the reaction portion 117, a surface area of the reaction portion 117 can be increased, usage efficiency of the reaction material included in the reaction portion 117 can be improved, and the reaction proceeds in a short time. Accordingly, heat accumulation and heat radiation in the heat exchanger 110 can be performed in a short time.

In the heat exchanger 110, which has the above described configuration, the heat exchange between the heat medium which flows in the plate fins 115 and the reaction portion 117 is performed by the reaction material, included in the reaction portion 117, reacting with the reaction medium in the exothermic manner and in the endothermic manner.

It should be noted a material other than gypsum may be used as the reaction material if the material can fill the gaps between the plate fins 115 and the corrugated fins 116 and be solidified.

Further, the number of holes 118 formed on the reaction portion 117, the shape and the production method of the holes 118 are not limited to the above descriptions.

<Production Method of the Heat Exchanger 110>

Next, a production method for producing the heat exchanger 110 will be described. FIG. 6 is a flowchart illustrating an example of the production method for producing the heat exchanger 110 according to the embodiment.

As shown in FIG. 6, in step S101, the reaction material slurry is made first. In the embodiment, as the reaction material slurry, hemihydrate gypsum, the setting retarder and water are kneaded (mixed) to make the gypsum slurry. Both type α and type β may be used as hemihydrate gypsum. For example, powdered, granular, or aggregated hemihydrate gypsum and the setting retarder may be used.

Quantities of water and the setting retarder combined with hemihydrate gypsum are set as appropriate in accordance with manageability when filling the gaps between the plate fins 115 and the corrugated fins 116 with the gypsum slurry, a time required for filling, and density and strength after being hardened.

For example, in a case in which a hydrosoluble setting retarder is used, the gypsum slurry is made by adding hemihydrate gypsum to setting retarder aqueous solution that is mixed liquid of the setting retarder and water, and kneading (mixing) the gypsum slurry and the mixed liquid. Further, in a case in which an insoluble setting retarder is used, the gypsum slurry is made by adding a compound of hemihydrate gypsum and the setting retarder to water, and kneading (mixing) the compound and the water. It should be noted that mixing temperature, a mixing time and the like are not limited specifically, as long as hemihydrate gypsum, the setting retarder and water can be mixed sufficiently.

Subsequently, in step S102, the reaction material slurry made in step S101 is poured into the gaps between the plate fins 115 and the corrugated fins 116 to fill the gaps. In order to improve usage efficiency of the reaction material, it is preferable to fill the gaps between the plate fins 115 and the corrugated fins 116 with the reaction material slurry tightly (with no gap).

In step S103, after filing the gaps between the plate fins 115 and the corrugated fins 116 with the reaction material slurry, the reaction material slurry is left. Then, the reaction material slurry is crystalized to be solidified to form the reaction portion 117. In other words, the reaction portion 117 is solidified by crystallization of the reaction material slurry. In the embodiment, when hemihydrate gypsum takes water into the crystals and the phase transition to gypsum dihydrate occurs, the gypsum slurry is corrugated and solidified, and the reaction portion 117 is formed.

In step S104, the reaction portion 117 was dried, for example, under a room temperature environment. In the embodiment, for example, gypsum dihydrate in which water remains between crystals in the reaction portion 117 was dried.

In step S105, the reaction portion 117 is burned, for example, at a temperature from 100 to 200 degrees Celsius, and at an atmospheric pressure or a reduced pressure. In the embodiment, gypsum dihydrate becomes III type anhydrous gypsum in the reaction portion 117.

In the heat exchanger 110, the reaction portion 117 is formed by the above described method.

It should be noted that the production method for producing the heat exchanger 110 is not limited to the above described method. For example, another step may be added as appropriate, and the fixed order may be changed.

PRACTICAL EXAMPLES

Next, reaction material blocks were made under conditions of following practical examples 1 to 6, and heat radiation (dissipation) characteristics and the like of the respective reaction material blocks were evaluated.

Practical Example 1

Gypsum slurry was obtained by adding 4000.0 parts by weight of distilled water to 10,000 parts by weight of type α hemihydrate gypsum (YG-KM, from Yoshino Gypsum Co., Ltd.) and mixing (kneading) them for about one minute.

A Gypsum block as a reaction material block was formed by pouring the gypsum slurry into a mold having a predetermined size (25 mm×25 mm×5 mm), leaving it for about 10 minutes, and solidifying it. Anhydrous gypsum was obtained by taking out the solidified gypsum block from the mold and drying it at 150 degrees Celsius for 5 hours. An effective density of the gypsum block after being dried was 1.30 g/cm3.

The dried state gypsum block made as described above was arranged in the reactor 100 of the chemical heat pump 10, and water vapwas supplied into the reactor 100 from the evaporator 300. When the water vapor was supplied into the reactor 100, the exothermic reaction to the right direction in the formula (1) proceeded, and the gypsum block radiated heat. Heat radiation characteristics in the practical example 1 were obtained by measuring temperature of the gypsum block for 10 minutes from starting heat radiation. FIG. 7 shows the heat radiation characteristics in the practical example 1.

Practical Example 2

An aqueous solution of citric acid was made by adding 66.4 parts by weight of citric acid as the setting retarder to 4023.8 parts by weight of distilled water. Gypsum slurry was obtained by adding 10,000 parts by weight of type a hemihydrate gypsum (YG-KM, from Yoshino Gypsum Co., Ltd.) to the made aqueous solution of citric acid, and mixing (kneading) them for about one minute.

A Gypsum block was formed by pouring the gypsum slurry into a mold (25 mm×25 mm×5 mm), leaving it for about 3 hours, and solidifying it. Anhydrous gypsum was obtained by taking out the solidified gypsum block from the mold and drying it at 150 degrees Celsius for 5 hours. An effective density of the gypsum block after being dried was 1.31 g/cm3.

Under a condition similar to the condition of the practical example 1, heat radiation characteristics in the practical example 2 were obtained by using the gypsum block made as described above. FIG. 8 shows the heat radiation characteristics in the practical example 2.

Practical Example 3

An aqueous solution of magnesium acetate was made by adding 77.0 parts by weight of magnesium acetate tetrahydrate as the setting retarder to 4026.8 parts by weight of distilled water. Gypsum slurry was obtained by adding 10,000 parts by weight of type a hemihydrate gypsum (YG-KM, from Yoshino Gypsum Co., Ltd.) to the made aqueous solution of magnesium acetate, and mixing (kneading) them for about one minute.

A gypsum block was formed by pouring the gypsum slurry into a mold (25 mm×25 mm×5 mm), leaving it for about 10 minutes, and solidifying it. Anhydrous gypsum was obtained by taking out the solidified gypsum block from the mold and drying it at 150 degrees Celsius for 5 hours. An effective density of the gypsum block after being dried was 1.35 g/cm3.

Under a condition similar to the condition of practical example 1, heat radiation characteristics in the practical example 3 were obtained by using the gypsum block made as described above. FIG. 9 shows the heat radiation characteristics in the practical example 3.

Practical Example 4

An aqueous solution of magnesium hydrogen citrate was made by adding 105.6 parts by weight of magnesium hydrogen citrate pentahydrate as the setting retarder to 4022.0 parts by weight of distilled water. Gypsum slurry was obtained by adding 10,000 parts by weight of type a hemihydrate gypsum (YG-KM, from Yoshino Gypsum Co., Ltd.) to the made aqueous solution of magnesium hydrogen citrate, and mixing (kneading) them for about one minute.

A Gypsum block was formed by pouring the gypsum slurry into a mold (25 mm×25 mm×5 mm), leaving it for about 5 hours, and solidifying it. Anhydrous gypsum was obtained by taking out the solidified gypsum block from the mold and drying it at 150 degrees Celsius for 5 hours. An effective density of the gypsum block after being dried was 1.45 g/cm3.

Under a condition similar to the condition of practical example 1, heat radiation characteristics in the practical example 4 were obtained by using the gypsum block made as described above. FIG. 10 shows the heat radiation characteristics in the practical example 4.

Practical Example 5

An aqueous solution of trimagnesium dicitrate was made by adding 53.2 parts by weight of trimagnesium dicitrate as the setting retarder to 4001.2 parts by weight of distilled water. Gypsum slurry was obtained by adding 10,000 parts by weight of type α hemihydrate gypsum (YG-KM, from Yoshino Gypsum Co., Ltd.) to the made aqueous solution of trimagnesium dicitrate, and mixing (kneading) them for about one minute.

A Gypsum block was formed by pouring the gypsum slurry into a mold (25 mm×25 mm×5 mm), leaving it for about 5 hours, and solidifying it. Anhydrous gypsum was obtained by taking out the solidified gypsum block from the mold and drying it at 150 degrees Celsius for 5 hours. An effective density of the gypsum block after being dried was 1.45 g/cm2.

Under a condition similar to the condition of practical example 1, heat radiation characteristics in the practical example 5 were obtained by using the gypsum block made as described above. FIG. 11 shows the heat radiation characteristics in the practical example 5.

Practical Example 6

Mixed powder was made by adding 199.9 parts by weight of calcium citrate as the setting retarder to 10,000 parts by weight of type a hemihydrate gypsum (YG-KM, from Yoshino Gypsum Co., Ltd.). Gypsum slurry was obtained by adding 4028.4 parts by weight of distilled water to the made mixed powder, and mixing (kneading) them.

A Gypsum block was formed by pouring the gypsum slurry into a mold (25 mm×25 mm×5 mm), leaving it for about 3 hours, and solidifying it. Anhydrous gypsum was obtained by taking out the solidified gypsum block from the mold and drying it at 150 degrees Celsius for 5 hours. An effective density of the gypsum block after being dried was 1.40 g/cm3.

Under a condition similar to the condition of practical example 1, heat radiation characteristics in the practical example 6 were obtained by using the gypsum block made as described above. FIG. 12 shows the heat radiation characteristics in the practical example 6.

As described above, the gypsum block was formed without using the setting retarder in the practical example 1, and the gypsum blocks were formed using the setting retarders in the practical examples 2 to 5. In the practical example 1 in which the setting retarder was not used, the gypsum slurry was solidified in a short time (about 10 minutes). On the other hand, in the practical examples 2 to 5 in which the setting retarders were used, a time for solidifying the gypsum slurry was prolonged to about 2 through 5 hours.

In this way, by prolonging the time for solidifying the gypsum slurry using the setting retarder, it becomes easy to fill the gaps between the plate fins 115 and the corrugated fins 116 of the heat exchanger 110 with the gypsum slurry. Further, it becomes easy to fill the gaps between the plate fins 115 and the corrugated fins 116 of the heat exchanger 110 with the gypsum slurry tightly (with no gaps).

Further, the effective densities of the practical examples 2 to 6, in which the setting retarders were used, were greater than the effective density of the practical example 1 in which the setting retarder was not used. By making the effective density greater, the heat radiation quantity and the heat accumulation quantity can be improved even if the same size gypsum block is used.

Further, as shown in FIGS. 7 to 12, peak temperatures of the respective practical examples 1 to 6 were about 185 degrees Celsius. The theoretical value of reaction equilibrium temperature when water vapor pressure 90 kPa is applied to anhydrous gypsum is about 186.7 degrees Celsius. In each of the practical examples 1 to 6, heat was generated almost theoretically.

In the radiation characteristics of the practical examples 1 to 6, the peak temperatures, required times to reach the peak temperatures, temperature changes after reaching the peak temperatures and the like had no major difference. As described above, even when the setting retarder was used, decrease of the radiation characteristics such as decrease of the peak temperature did not occur.

Practical Example 7

A reaction portion 117 was formed by filling the gaps between the layered (arranged) plate fins 115 and the corrugated fins 116 with gypsum slurry, made by using magnesium acetate tetrahydrate as the setting retarder similar to the practical example 3, to solidify the gypsum slurry. Further, the gypsum slurry was dried at 150 degrees Celsius for 5 hours, and a heat exchanger 110 of the practical example 7 having a configuration similar to the configuration shown in FIG. 4 was made.

In a heat exchanger 110 of the practical example 7, a clearance between the introduction tank 113 and the discharging tank 114 was 22 cm. The plate fins 115 and the corrugated fins 116 were layered alternately between the introduction tank 113 and the discharging tank 114. Each of the plate fins 115 had a length of 22 cm, a width of 2 cm, and a thickness of 2 mm. Clearances between the plate fins 115 were 8 mm. Each of the corrugated fins 116 had a thickness of 0.1 mm. Clearances between the corrugated fins 116 were 1.6 mm. Weight of the reaction portion 117 formed on the heat exchanger 110 of the practical example 7 was about 1033 g.

The heat exchanger 110 of the practical example 7, including the above described configuration, was arranged in the reactor 100 of the chemical heat pump 10, and the following heat accumulation operation and the heat radiation operation were performed. During the heat accumulation operation, a heat medium at 150 degrees Celsius was introduced into the heat exchanger 110 to proceed with an endothermic reaction in the reaction portion 117. Heat of the heat medium was accumulated to the reaction portion 117 by the endothermic reaction, the heat medium, whose heat was absorbed and whose temperature was lowered, was discharged from the heat exchanger 110.

Water vapor generated by the endothermic reaction in the reaction portion 117 was introduced to the condenser 200 through the first connection pipe 11 by opening the first valve 21. By setting a water vapor pressure of the condenser 200 as 1.5 kPa, water vapor introduced to the condenser 200 is liquefied.

During the heat radiation operation, a water vapor pressure of the evaporator 300 was set as kPa and the second valve 22 was opened to introduce water vapor to the reactor 100 through the second connection pipe 12. When the water vapor was supplied to the reactor 100, the exothermic reaction proceeded in the reaction portion 117, and the heat medium, heated and whose temperature was raised by the reaction portion 117, was discharged from the heat exchanger 110.

The above described heat radiation operation was performed for 30 minutes after the above described heat accumulation operation was performed for 30 minutes. Then, evaluation of a heat quantity accumulated by the heat exchanger 110 of the practical example 7 and a heat quantity radiated (dissipated) by the heat exchanger 110 of the practical example 7 was performed based on a time required for reaching 70 percent of the total heat quantity. In the heat exchanger 110 of the practical example 7, a heat accumulation time was about 1503 seconds and a heat accumulation speed was about 92 W. Further, a heat radiation time was about 323 seconds and a heat radiation speed was about 426 W. The generated total heat quantity was about 196.6 kJ, the theoretical heat quantity calculated based on a supplied quantity of anhydrous gypsum (quantity of anhydrous gypsum filling the gaps) was about 249.54 kJ, and usage efficiency of the reaction portion in the heat exchanger 110 in the practical example 7 was about 79 percent.

It should be noted that the heat quantity emitted from the heat exchanger 110 can be calculated by integrating output q, calculated by the following formula (2), by time.


q=C×(Tin−Tout)×ρ×f/6O   (2)

  • q: heat output [W]
  • Tin: introduction temperature of heat medium [degrees Celsius]
  • Tout: discharging temperature of heat medium [degrees Celsius]

C: specific heat of heat medium [J/(kg·K)]

ρ: density of heat medium [kg/m3]

f: volume flow of heat medium [m3/min]

For example, in a case in which the heat medium is silicone oil, C=1600 J/(kg·K) and ρ=960 kg/m3

Practical Example 8

Using gypsum slurry, made by adding magnesium acetate tetrahydrate as the setting retarder similar to the practical example 3, a heat exchanger 110 of the practical example 8 including a plurality of holes 118 similar to the configuration shown in FIG. 5 was made. The holes 118 were formed one by one between two plate fins 115. An opening portion of each of the holes 118 has a predetermined size (200 mm×1 mm). The holes 118 penetrate the reaction portion 117. The configuration, including the plate fins 115 and the corrugated fins 116, other than the holes 118 was similar to the configuration of the practical example 7. Weight of the reaction portion 117 formed on the heat exchanger 110 of the example 8 was about 900 g.

The heat exchanger 110 of the practical example 8, including the above described configuration, was arranged in the reactor 100 of the chemical heat pump 10, and the heat accumulation operation and the heat radiation operation were performed similar to the practical example 7. Then, evaluation of a heat quantity accumulated by the heat exchanger 110 of the practical example 8 and a heat quantity radiated by the heat exchanger 110 of the practical example 8 was performed based on a time required for reaching 70 percent of the total heat quantity. In the heat exchanger 110 of the practical example 8, a heat accumulation time was about 398 seconds and a heat accumulation speed was about 317 W. Further, a heat radiation time was about 211 seconds and a heat radiation speed was about 598 W. The generated total heat quantity was about 180.3 kJ, the theoretical heat quantity calculated based on a supplied quantity of anhydrous gypsum (quantity of anhydrous gypsum filling the gaps) was about 217.41 kJ, and usage efficiency of the reaction material in the heat exchanger 110 in the practical example 8 was about 83 percent.

Comparative Example 1

A heat exchanger 110 of a comparative example 1 was made by filling the gaps between the plate fins 115 and the corrugated fins 116 with powder of type β hemihydrate gypsum (Sakura gypsum A class, from Yoshino Gypsum Co., Ltd.) as a reaction material. The configuration, including the plate fins 115 and the corrugated fins 116, other than the reaction portion 117 was similar to the configuration of the practical example 7. Weight of the hemihydrate gypsum supplied in the heat exchanger 110 of the comparative example 1 was about 610 g.

The heat exchanger 110 of the comparative example 1, including the above described configuration, was arranged in the reactor 100 of the chemical heat pump 10, and the heat accumulation operation and the heat radiation operation were performed similar to the practical example 7. Then, evaluation of a heat quantity accumulated by the heat exchanger 110 of the comparative example 1 and a heat quantity radiated by the heat exchanger 110 of the comparative example 1 was performed based on a time required for reaching 70 percent of the total heat quantity. In the heat exchanger 110 of the comparative example 1, a heat accumulation time was about 1320 seconds and a heat accumulation speed was about 53 W. Further, a heat radiation time was about 264 seconds and a heat radiation speed was about 266 W. The generated total heat quantity was about 100.3 kJ, the theoretical heat quantity calculated based on a supplied quantity of anhydrous gypsum was about 146.35 kJ, and usage efficiency of the reaction material in the heat exchanger 110 in the comparative example 1 was about 69 percent.

Because the gaps between the plate fins 115 and the corrugated fins 116 in the heat exchangers 110 of the practical example 7 and the practical example 8 were filled with the reaction material in the reaction material slurry state, the heat exchangers 110 of the practical example 7 and the practical example 8 include the reaction material in the reaction portion 117 more than the reaction material supplied, in the powder state, in the heat exchanger 110 of the comparative example 1.

Thus, although the reaction heat quantity in the comparative example 1 was about 100 kJ, the reaction heat quantity in the practical example 7 was about 195 kJ and the reaction heat quantity in the practical example 8 was about 180 kJ. That is, the reaction heat quantity in the practical example 7 and the reaction heat quantity in the practical example 8 were considerably increased in comparison with the reaction heat quantity in the comparative example 1.

Further, in the heat exchangers 110 of the practical example 7 and the practical example 8, the reaction material was supplied, in the reaction material slurry state, into the gaps between the plate fins 115 and the corrugated fins 116, and the reaction portion 117, the plate fins 115 and the corrugated fins 116 were integrally formed. According to the above described configuration, in the heat exchangers 110 of the practical example 7 and the practical example 8, heat exchanging efficiency between the reaction material and the heat medium was improved in comparison with the heat exchanger 110 of the comparative example 1 in which the reaction material was supplied in the powder state.

Thus, the usage efficiency of the reaction material in the practical example 7 was about 79 percent and the usage efficiency of the reaction material in the practical example 8 was about 83 percent. That is, the usage efficiencies of the practical examples 7 and 8 were considerably improved in comparison with the usage efficiency (about 69 percent) of the reaction material in the comparative example 1.

Further, because the holes 118 were disposed on the heat exchanger 110 in the practical example 8, the usage efficiency of the reaction material in the practical example 8 was improved to about 83 percent from the usage efficiency about 79 percent in the practical example 7.

As described above, in the heat exchangers 110 of the practical example 7 and the practical example 8, the reaction material was supplied, in the reaction material slurry state, into the gaps between the plate fins 115 and the corrugated fins 116. Thus, the heat exchangers 110 of the practical example 7 and the practical example 8 included the reaction material in the reaction portion 117 more than the reaction material supplied, in the powder state, in the heat exchanger 110 of the comparative example 1 and the gaps between the plate fins 115 and the corrugated fins 116 were reduced. As a result, heat conductivities of the heat exchanger 110 of the practical example 7 and the practical example 8 were improved. Thus, the heat accumulation speed (about 92 W) and the heat radiation speed (about 426 W) in the practical example 7 and the heat accumulation speed (about 317 W) and the heat radiation speed (about 598 W) in the practical example 8 were greater than the heat accumulation speed (about 53 W) and the heat radiation speed (about 226 W) of the comparative example 1.

Further, because the holes 118 were formed in the heat exchanger 110 of the practical example 8, the surface areas of the reaction portion 117 were increased. Thus, the reaction between the reaction material and the reaction medium proceeded in a shorter time in comparison with the heat exchanger 110 of the practical example 7 in which the holes 118 were not formed. Thus, in comparison with the heat accumulation speed (about 92 W) and the heat radiation speed (about 426 W) in the heat exchanger 110 of the practical example 7, the heat accumulation speed (about 317 W) and the heat radiation speed (about 598 W) in the heat exchanger 110 of the practical example 8 were greater.

FIG. 13 shows the heat accumulation characteristics of the heat exchangers 110 in the practical example 7 and the practical example 8.

Further, FIG. 14 shows the heat radiation characteristics of the heat exchangers 110 in the practical example 7 and the practical example 8.

The heat accumulation characteristics shown in FIG. 13 and the heat radiation (dissipation) characteristics shown in FIG. 14 are expressed by change of ΔT (ΔT=Tout−Tin) with respect to time. Tin is a temperature of the heat medium at the heat medium introduction port 111 shown in FIG. 4. Tout is a temperature of the heat medium at the heat medium discharging port 112. ΔT is the difference between Tin and Tout. It should be noted that silicone oil was used as the heat medium, and ΔT was monitored by pouring the silicone oil into the heat exchanger 110 at the rate of 2 L per minute (2 L/min).

As shown in FIG. 13, because the holes 118 were disposed, the heat exchanger 110 in the practical example 8 could accumulate heat in a shorter time than the heat exchanger 110 in the practical example 7. Further, as shown in FIG. 14, because the holes 118 were disposed, the heat exchanger 110 in the practical example 8 could radiate heat in a shorter time than the heat exchanger 110 in the practical example 7 though the difference was not so remarkable as compared to the heat accumulation operation.

The following table 1 indicates the respective characteristics of the practical example 7, the practical example 8 and the comparative example 1.

PRACTICAL PRACTICAL COMPARATIVE EXAMPLE 7 EXAMPLE 8 EXAMPLE 1 GYPSUM 1033 g 900 g 606 g QUANTITY HEAT 323 s 211 s 264 s RADIATION TIME HEAT 426 W 598 W 266 W RADIATION SPEED HEAT 1503 s 398 s 1320 s ACCUMULATION TIME HEAT 92 W 317 W 53 W ACCUMULATION SPEED TOTAL HEAT 196.6 kJ 180.3 kJ 100.3 kJ RADIATION QUANTITY USAGE 79% 83% 69% EFFICIENCY

The heat radiation time and the heat accumulation time shown in the table 1 are times required for reaching 70 percent of the total heat quantity. Further, the heat radiation speed and the heat accumulation speed are values calculated based on the above described the heat radiation time and the heat accumulation time.

As described above, according to the embodiment of the heat exchanger 110, because the reaction portion 117, the plate fins 115, and the corrugated fins 116 are formed integrally, the usage efficiency of the exothermic reaction and the endothermic reaction by the reaction material can be improved. Further, according to the chemical heat pump 10 including the heat exchanger 110, it becomes possible to radiate and accumulate heat more effectively.

Although the heat exchanger 110, the chemical heat pump 10, and the production method for producing the heat exchanger 110 are described according to the embodiment, the present invention is not limited to the embodiment and the practical examples, but various variations and modifications may be made without departing from the scope of the present invention.

The present application is based on and claims the benefit of priority of Japanese Priority Application No. 2015-095420 filed on May 8, 2015 and Japanese Priority Application No. 2015-215159 filed on Oct. 30, 2015 with the Japanese Patent Office, the entire contents of which are hereby incorporated by reference.

Claims

1. A heat exchanger comprising:

a plurality of plate fins including a plurality of flow channels in which a heat medium flows;
a plurality of corrugated fins, the plurality of plate fins and the plurality of corrugated fins being arranged alternately; and
a reaction portion solidified by crystallization of reaction material slurry filling gaps between the plurality of plate fins and the plurality of the corrugated fins, the reaction material slurry including a reaction material that reversibly reacts with a reaction medium in an exothermic manner and in an endothermic manner to exchange heat with the heat medium.

2. The heat exchanger according to claim 1, wherein the reaction material is hemihydrate gypsum or III type anhydrous gypsum.

3. The heat exchanger according to claim 2, wherein the reaction material slurry includes a setting retarder.

4. The heat exchanger according to claim 1 wherein the reaction portion includes a plurality of holes.

5. A chemical heat pump comprising:

a reactor including the heat exchanger according to claim 1;
a reaction medium supplying unit configured to supply the reaction medium to the reactor; and
a reaction medium recovery unit configured to recover the reaction medium from the reactor.

6. A production method for producing a heat exchanger in which a plurality of plate fins including a plurality of flow channels where a heat medium flows and a plurality of corrugated fins are arranged alternately, the production method comprising;

a slurry making step of making reaction material slurry including a reaction material that reversibly reacts with a reaction medium in an exothermic manner and in an endothermic manner to exchange heat with the heat medium;
a filling step of filling gaps between the plurality of plate fins and the plurality of corrugated fins with the reaction material slurry; and
a reaction portion forming step of forming a reaction portion by solidifying the reaction material slurry filling the gaps between the plurality of plate fins and the plurality of corrugated fins.

7. The production method for producing the heat exchanger according to claim 6, wherein the reaction material slurry is made in the slurry making step by adding the reaction material to mixed liquid of a setting retarder and water and mixing the reaction material and the mixed liquid. 15

8. The production method for producing the heat exchanger according to claim 6, wherein the reaction material slurry is made in the slurry making step by adding water to a compound of the reaction material and a setting retarder and mixing the water and the compound.

9. The production method for producing the heat exchanger according to claim 6, wherein the reaction portion forming step includes a drying step of drying the reaction portion, and a burning step of burning the reaction portion.

Patent History
Publication number: 20160327315
Type: Application
Filed: Apr 28, 2016
Publication Date: Nov 10, 2016
Applicant: Ricoh Company, Ltd. (Tokyo)
Inventors: Masahiro MASUZAWA (Kanagawa), Yasutomo AMAN (Kanagawa), Yohei SHIREN (Tokyo), Hiroko OHKURA (Kanagawa), Tomiko TAKAHASHI (Kanagawa), Yoshifumi OHBA (Kanagawa), Kohji TSUKAHARA (Kanagawa)
Application Number: 15/140,826
Classifications
International Classification: F25B 30/04 (20060101); F25B 17/08 (20060101); F28F 3/04 (20060101); F28D 9/00 (20060101);