JP2007239697A - High temperature region cooling device using latent heat transporting inorganic hydrate slurry - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high temperature region cooling device using a latent heat material for efficiently cooling a high temperature object. <P>SOLUTION: The high temperature region cooling device comprises a first heat exchanger 1 for heat exchange with a high temperature object to be cooled, a second heat exchanger 2 for heat exchange with low temperature fluid as a low heat source, and a pipe system consisting of a circulation duct for heat medium to circulate through the first and second heat exchangers and a heat medium pump 3. The used heat medium is solution whose solvent contains a phase transition inorganic material to be solidified in the second heat exchanger 2 and to be liquefied in the first heat exchanger 1 in the condition that at least part is not dissolved, and which has a latent heat absorbing region in an operating temperature range of the heat medium. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a high-temperature region cooling apparatus that performs high-efficiency heat transport using a heat medium that uses the latent heat of phase change between solid liquids for high-temperature objects such as various engines.

  In the cooling of a high temperature object and the temperature control of a thermostatic bath or a warehouse, it is necessary to transport heat between a high temperature heat source and a low temperature heat source using a heat medium. At this time, the larger the heat transport capacity of the heat medium used, the smaller the heat medium transport amount. Since the pump power required for the predetermined flow rate is substantially proportional to the cube of the flow rate, it is possible to operate economically by reducing the heat medium transport amount and suppressing the power of the heat medium pump.

FIG. 8 is a block diagram showing a typical example of an engine cooling device. As shown in the figure, water is used as the heat medium, and the heat medium is circulated between the engine that is the high-temperature heat source and the radiator that is the low-temperature heat source by the pump, and the heat absorbed by the engine is exchanged between water and air using the radiator. To cool the engine by releasing heat generated in the engine to the atmosphere. The radiator has a cooling fan that blows outside air onto the fins.
In the drawing, the lines indicated by dotted lines at the positions of the engine and the radiator schematically indicate that the temperature of the heat medium changes substantially linearly by exchanging heat at the respective positions.

  The heating medium is heated by the engine, sent to the radiator, cooled by air cooling, and sent to the engine again. Since the engine load condition fluctuates greatly, it is necessary to accurately maintain the proper temperature of the coolant in order to ensure engine operating efficiency. For this reason, the thermostat is installed in the circulation path of the heat medium, and when the temperature of the heat medium changes, the valve operates to control the amount of the heat medium that bypasses the radiator, thereby adjusting the coolant temperature appropriately. The reservoir tank serves to prevent cavitation that tends to occur on the suction side of the pump by escaping the vaporized gas generated from the heat medium. The water temperature sensor monitors the abnormality of the cooling system by measuring the temperature of the heat medium at the engine side outlet.

  As described above, when the purpose is to cool high-temperature heating elements such as automobile engines, motorcycle engines, marine engines, and generator engines, a large amount of heat must be removed in a short time. In addition, the heat transfer amount is increased by using a heat medium mainly composed of water and having a large specific heat, and the heat transfer amount is reduced and the pump power is suppressed. However, the sensible heat of water is only 4.2 kJ / kg, and there is a limit to the suppression of the transport amount of the heat medium and the transport power.

On the other hand, in recent years, attention has been paid to latent heat that is overwhelmingly greater than sensible heat, and a slurry in which a substance having latent heat (hereinafter referred to as a latent heat substance) is suspended has been developed.
Since the latent heat of the phase transition is several tens of times greater than the sensible heat of water, efficient heat transport becomes possible if a latent heat substance is used. Although it is well known to use a latent heat substance as the heat storage material, various kinds of latent heat substances can be used because the heat storage material itself does not need to flow.
In contrast, a heat medium that uses latent heat to transport a large amount of heat between a high-temperature heat source and a low-temperature heat source needs to undergo phase transition when heat exchange is performed between the high-temperature heat source and the low-temperature heat source. Therefore, since the latent heat substance is solidified in the low temperature side heat exchanger and moved to the high temperature side heat exchanger as a solid, it must be able to flow. Therefore, it is desirable that the heating medium when transported from the low temperature heat source to the high temperature heat source is in the form of a slurry that conveys the latent heat substance solidified by the low temperature heat source.

As such a latent heat transport slurry, ice water slurry is well studied. Ice water slurry uses the latent heat of ice to transport heat, so it can transport a large amount of heat at a low cost. However, it is not only easy to block piping due to ice blocks, but it can only be used for cold transport. There is.
In addition, by suspending a latent heat substance having a phase transition point in a higher temperature range in a heating medium and making it into a slurry, the application range can be expanded to a higher temperature target. Examples of the latent heat substance suspended in the heat medium include paraffin, hydrate, hydrate, and those obtained by microencapsulating these, and it is preferable to select a target to be used according to the phase transition point.

  For example, Patent Document 1 discloses an air conditioner that uses a hydrate slurry in which an organic hydrate is suspended in a cooling cycle and uses an inorganic hydrate slurry in a heating cycle. . In the disclosed air conditioning equipment, for heating, for example, an aqueous solution in which 44.4 wt% of sodium acetate trihydrate is contained in ion-exchanged water is used as a heat medium having a melting point of 50 to 60 ° C., and 54 ° C. It has been confirmed that hydrate particles are formed in the vicinity.

Organic hydrates are also called clathrate hydrates because water molecules are arranged in a cage shape, and they are effective because they have relatively large latent heat, are stable and have little subcooling, but are generally expensive. In addition, it has a low phase transition point and is difficult to apply to a high-temperature heat source.
Inorganic hydrates are substances in which water molecules are incorporated as crystal water in crystals, and some are inexpensive and have high latent heat, and are often applied to high-temperature heat equipment and heat engines. However, since the solubility in the solvent is relatively high in the high temperature region such as during operation of a heat engine or the like, the hydrate does not solidify even when the hydrate dissolves in the solvent and falls below the phase transition point, and does not absorb latent heat. Some cases also appear.

In order to utilize the phase transition of the latent heat substance, it is necessary that the latent heat substance exists in a solid state even when the heat medium absorbs heat from the high temperature heat source. Moreover, it is preferable that the solid latent heat substance contained in the heat medium is in the form of particles and easily suspended in the solvent and can be easily transported.
JP 2005-029591 A

  Therefore, the problem to be solved by the present invention is to provide a high-temperature region cooling device that efficiently cools a high-temperature object using a latent heat substance.

  In order to solve the above-described problems, a high-temperature region cooling apparatus of the present invention includes a first heat exchanger that exchanges heat with a high-temperature object to be cooled, a second heat exchanger that exchanges heat with a low-temperature fluid that serves as a low heat source, and the first heat exchanger. And a piping system formed by a circulation pipe for circulating the heat medium through the second heat exchanger and the heat medium pump, and solidified in the second heat exchanger as the heat medium in the first heat exchanger A feature is that a solution containing a phase transition inorganic substance liquefied in a solvent in a state where at least a part of the inorganic substance is not dissolved is used.

  In the cooling device of the present invention, cooling is performed by utilizing the latent heat of the phase change inorganic substance, so that the flow rate of the heat medium may be small, and the transport power of the heat medium pump can be reduced. The substantial phase transition point of the heat medium is intermediate between the outlet temperature of the first heat exchanger and the outlet temperature of the second heat exchanger, and the temperature of the heat medium is changed during the phase change in the heat exchanger. Since the temperature difference is maintained without changing, the efficiency of heat exchange is improved and the efficiency of the cooling device is improved.

The phase change inorganic substance, that is, the latent heat substance solidified by the second heat exchanger on the low temperature side, is contained in the solvent in the form of particles and becomes a heat medium slurry. The solvent slurry is conveyed to the first heat exchanger on the high temperature side and absorbs heat from the high temperature object. The latent heat substance in the heat medium takes away the heat of the latent heat and liquefies.
The heat medium containing the latent heat substance liquefied by the first heat exchanger is transported to the second heat exchanger and exchanges heat with a low-temperature fluid such as outside air to dissipate heat. The latent heat substance contained in the heat medium is cooled and solidified into particles, and the heat medium is slurried. In this way, the heat of the high temperature object is released and cooled.

The object to be cooled may be an engine, and the first heat exchanger may be an engine wall and the second heat exchanger may be a radiator.
It is preferable that the second heat exchanger is provided with a mechanism such as a torsion tape for preventing the heat medium flow from going straight in at least some of the pipes.

It is preferable that the heat medium used in the high-temperature region cooling apparatus of the present invention has a substantial phase transition point in the range of 60 ° C to 120 ° C. In particular, when a radiator-cooled engine is targeted, one in the range of 70 to 90 ° C. is selected.
The heat medium preferably contains a resistance reducing agent that reduces flow resistance.
In addition, it has been observed that the heat medium containing the phase change inorganic substance that is a latent heat substance in a state in which a part thereof is not dissolved has a substantial latent heat absorption region at a temperature lower than the phase transition point of the pure phase change inorganic substance. .
When a considerable amount of phase change inorganic substance is added using a solution obtained by adding an alcohol that hardly dissolves phase change inorganic substance such as ethylene glycol to alum as a solvent, the phase change inorganic substance remains undissolved even in the first heat exchanger on the high temperature side. Can be.

Alum (monovalent cation and trivalent cation sulfate double salt), especially potassium aluminum sulfate dodecahydrate (potassium alum: KAl (SO ₄ ) ₂ · 12H ₂ O) is used as a latent heat substance. When the ratio of the solvent water to ethylene glycol is in the range of 3: 7 to 7: 3, the substantial phase transition point is between 70 ° C. and 85 ° C., and the substantial latent heat of the heating medium is 10 kJ. Since it is about 35 kJ / kg from / kg, a heat medium flow rate that is a fraction of that in the case of using sensible heat of water is sufficient.
As alum, aluminum ammonium sulfate dodecahydrate (Al (NH ₄ ) (SO ₄ ) ₂ · 12H ₂ O) and iron alum hexahydrate (Fe (NH ₄ ) (SO ₄ ) ₂ · 6H ₂ O) may be used.
Incidentally, aluminum sulfate fourteen-octadecahydrate instead of alum _{(Al 2 (SO 4) 3} · 14~18H 2 O) can also be used.

Accordingly, the transport capacity of the heat medium pump is only a fraction, and the cooling device can be downsized.
Further, the temperature of the heat medium does not change so much during solidification or liquefaction in the heat exchanger, and the temperature difference from the heat source is maintained, so that the efficiency of the cooling device is improved.

Hereinafter, the present invention will be described in detail based on examples with reference to the drawings.
FIG. 1 is a block diagram showing an example of a cooling device according to the present invention, FIG. 2 is a perspective view showing an example of a low temperature side heat exchanger used in the cooling device of the present invention, and FIG. 3 explains the structure of the heat exchanger. FIG. 4 is a partially cutaway perspective view, FIG. 4 is a diagram for explaining the solubility of the latent heat substance in the heat medium, FIG. 5 is a diagram for measuring the latent heat of the heat medium, and FIG. 6 is a graph showing the temperature change of the heat medium in the heat exchanger. FIG. 7 is a diagram illustrating the relationship between the content of the latent heat substance, the required flow rate, and the pump power, and FIG. 8 is a block diagram of a conventional cooling device.

The high temperature zone cooling device of the present embodiment is an example in which the present invention is applied to an engine cooling device, and there is no change in configuration from the conventional cooling device shown in FIG. 8, but the heat medium does not dissolve the latent heat substance. It is contained in a state, and there is a difference in that the capacity of the pump is particularly small and the apparatus is economical.
The cooling device is provided with a high temperature side heat exchanger 1 in an engine that is a high temperature heat source, a radiator that is a low temperature side heat exchanger 2 is arranged, the two heat exchangers are connected by piping, and a heat medium is circulated by a pump 3. The engine is cooled by releasing the heat absorbed from the engine into the atmosphere with a radiator. The radiator is provided with a cooling fan 4.

  The heat medium absorbs the heat of the engine in the high temperature side heat exchanger 1 and rises in temperature, cools in the low temperature side heat exchanger 2, and is sent to the high temperature side heat exchanger 1 again. In order to keep the temperature of the heat medium properly, a thermostat valve 5 is installed in the heat medium circuit, and the amount of heat medium that bypasses the low temperature side heat exchanger 2 is controlled based on the heat medium temperature. The low-temperature side heat exchanger 2 is provided with a reservoir tank 6 to escape the transpiration gas generated from the heat medium, thereby preventing cavitation of the pump 3. The water temperature sensor 7 measures the temperature of the heat medium at the outlet of the high temperature side heat exchanger 1 and monitors the cooling system for abnormalities.

In this example, an inorganic hydrate is selected as the latent heat substance, and an alcohol in which the inorganic hydrate is difficult to dissolve is mixed with water at a predetermined ratio to form a solvent. A solution mixed with an amount of inorganic hydrate sufficient to partially remain undissolved is used as a heating medium.
Then, the heat medium supplied in a high temperature state to the radiator which is the low temperature side heat exchanger 2 is cooled by exchanging heat with the atmosphere. The temperature of the heat medium in the radiator decreases as it cools, but when the phase transition point is reached, the latent heat substance precipitates and solidifies in the form of particles and maintains the phase transition temperature until phase conversion is completed, and then further cools. And discharged from the radiator outlet at low temperature.
The temperature change of the heat medium is schematically shown by the dotted line 9 at the position of the heat exchanger 2 in the figure.
Since the heat medium temperature does not change during the phase transition, the temperature difference from the outside air temperature is kept large, and the cooling efficiency is improved.

The heat medium cooled by the radiator is supplied to the high temperature side heat exchanger 1 provided in the engine by the pump 3. In the high temperature side heat exchanger 1, the heat medium absorbs the heat of the engine and rises in temperature, and when the phase transition point is reached, the particulate latent heat substance melts and liquefies, and the phase transition temperature is maintained until phase transformation is completed. To do. Thereafter, it is further heated and discharged from the outlet of the high temperature side heat exchanger 1 in a high temperature state.
The temperature change of the heat medium in the engine portion is schematically shown by the dotted line 8 at the position of the heat exchanger 1 in the figure.
Since the latent heat is larger than the sensible heat, the heat medium used in the present embodiment requires a small amount to receive the same amount of heat. Therefore, the capacity of the heat medium pump 3 can be small.
Further, when using a cooling medium by sensible heat, the heat medium of this embodiment absorbs latent heat in the heat exchanger 1 as compared with the fact that the temperature of the medium rises as the heat is absorbed and the temperature difference from the heating element becomes smaller. Since the same temperature is maintained during this period, the cooling efficiency is high.

When the heating medium is cooled, inorganic hydrates are precipitated, so that the viscosity of the heating medium is increased. Therefore, the flow rate of the heating medium may be reduced and transportation may be difficult. For this reason, it is preferable to add a surfactant as a resistance reducing agent.
As a cationic resistance reducing agent, a compound obtained by adding 1200 ppm sodium salicylate as a counter ion to 2000 ppm behenyltrimethylammonium chloride (trade name Arqurdo 2/80) has a high effect. In addition, the cationic resistance reducing agent has an effect of reducing the particle size of the particles on which the latent heat substance is deposited by adding 2000 ppm or more together with sodium salicylate, and improves the heat exchange performance. Enable the device.

FIG. 2 is a perspective view showing an example of a radiator used in this embodiment, and FIG. 3 is a partially cutaway view showing an enlarged portion thereof.
Since a small amount of the heat medium having a relatively high viscosity is circulated, the flow rate inside the heat exchanger is reduced and the heat passage coefficient is reduced. Therefore, as shown in FIG. 3, the heat exchanger 10 illustrated in FIG. 2 is a portion where the high temperature medium and the low temperature medium are in contact with flow path walls on different sides, and the heat medium passage has a circular cross section. 11 is preferably used with the twisted tape 12 inserted.

  By inserting the torsion tape 12, the flow rate in the vicinity of the wall surface can be increased and the flow in the pipe can be disturbed even at a small flow rate, and the heat transfer performance can be improved. Further, for example, alum has a specific gravity of 1.75, whereas ethylene glycol has a density of about 1.12. Therefore, the centrifugal heat generated by the torsion tape 12 collects particles of the latent heat substance near the wall surface and uses the latent heat. The exchange is effectively performed near the pipe wall.

  A thermostat valve that can introduce a heat medium from the engine side heat exchanger is installed at the outlet of the radiator. When the temperature of the heat medium changes, the amount of the heat medium that bypasses the radiator is controlled to adjust the coolant temperature appropriately. The radiator is provided with a reservoir tank to prevent cavitation generated by the pump, and a water temperature sensor provided at the engine side outlet measures the temperature of the heat medium and monitors the cooling system for abnormality.

The heating medium used in the cooling device of the present example is a solution in which potassium alum is mixed in a solution in which ethylene glycol is mixed with water in an amount that does not partially dissolve in the operating temperature range, and a resistance reducing agent is added. It has a substantial latent heat expression region in a region at a temperature lower than the phase transition point of alum, and has a characteristic of becoming particulate when alum precipitates.
Potassium alum (KAl (SO ₄ ) ₂ · 12H ₂ O) has a phase transition point of 92.5 ° C. and absorbs 238 kJ / kg of latent heat. Ethylene glycol is an alcohol that hardly dissolves potassium alum.

FIG. 4 is a graph showing the results of measuring the solubility of potassium alum in a mixed solution of water and ethylene glycol.
When the solvent is 100% water, the solubility is very high in the high temperature range, and the solubility is 250 g / 100 g near the phase transition point of potassium alum. On the other hand, the solubility is about 10 g / 100 g at room temperature. For this reason, in order for 20% latent heat transport particles to be present near the phase transition point, it is necessary to mix 320 g of potassium alum with respect to 100 g of the solvent, but this solution precipitates 310 g of solids at room temperature. It will be. In this state, it cannot be used as a latent heat transport medium.

On the other hand, in a solvent mixed with alum poorly soluble ethylene glycol, the solubility is remarkably reduced almost in proportion to the mixing ratio of ethylene glycol.
Therefore, the latent heat was measured for a heating medium in which potassium alum was added to a solvent in which ethylene glycol and water were mixed at different ratios so that about 20 wt% solid content remained in the latent heat absorption region. FIG. 5 shows a DSC curve obtained by measurement with a differential scanning calorimeter. For reference, the DSC curve of the potassium alum powder is also shown in the figure.

From the figure, it can be seen that the powdery pure alum absorbs latent heat in a narrow temperature range, while the mixed solution absorbs latent heat in a relatively wide temperature range of 60 to 85 ° C. The latent heat of the heat medium obtained by integrating the DSC curve is about 10 to 35 kJ / kg, which is several times that of 4.2 kJ / kg, which is the sensible heat of water. The latent heat of pure water alum was 229 kJ / kg, which almost coincided with the literature value.
Furthermore, it can be seen that when the concentration of ethylene glycol in the solvent is 80 wt% or more, the DSC curve overlaps on the horizontal axis of the figure and no latent heat appears. This is because the hydrate is not formed because the ratio of water molecules decreases.
Thus, heat transport using latent heat becomes possible by using a heat medium in which an appropriate amount of inorganic hydrate is added to a mixture of a poorly soluble solvent in water at a predetermined ratio.

Although not shown in the figure, from the result of measuring latent heat with a differential scanning calorimeter by adding aluminum sulfate 14 to 18 hydrate whose phase transition point peak is actually measured at 113 ° C. to an aqueous solution added with ethylene glycol, It was found that the latent heat absorption of the heat medium appears in the range of 60 ° C to 90 ° C.
Moreover, from the result of measuring latent heat by adding aluminum ammonium sulfate dodecahydrate having a phase transition point of 92.5 ° C. to an ethylene glycol aqueous solution, it was found that the latent heat absorption region of the heating medium is around 60 ° C. to 90 ° C. It was.
Further, the phase transition point was found that aqueous alcohol solutions can be sufficiently utilized iron alum hexahydrate _{108~117 ℃ (Fe (NH 4)} (SO 4) 2 · 6H 2 O). In these hydrates, potassium alum has the largest amount of latent heat absorption and has a large cooling effect.

Although the fluidity of the heat medium depends on the shape of the precipitated inorganic hydrate, it has been found that the particle size of the latent heat substance can be reduced by adding 2,000 wtppm or more of the cationic resistance reducing agent to the heat medium. Yes.
In this embodiment, potassium alum is used as a latent heat substance, and a latent heat substance is used by using a solvent in which behenyltrimethylammonium chloride (trade name: Arqurdo 2/80) 2000 wtppm is added with a resistance reducing agent in which 1200 wtppm sodium salicylate is added as a counter ion. It has been confirmed that the diameter of the particles formed when deposited is adjusted to about 0.2 mm.

In addition, the particle size of the latent heat substance does not change greatly while the heat medium circulates in the piping system.
Since the particles of the latent heat material are sufficiently small, they are easily transported by the solvent, and the heat medium slurry distributes the latent heat material evenly in the narrow channel, so use a smaller heat exchanger while maintaining the performance. Can do.
By using a heat medium containing a latent heat substance that cannot be completely dissolved, for example, the temperature change of the medium in a co-current heat exchanger is as shown in FIG.
That is, if the high-temperature side heat medium is a circulating liquid containing a latent heat substance and the low-temperature side heat medium is a cooling fluid such as air or cooling water, the high-temperature Th0 circulating liquid that has flowed into the heat exchanger is cooled to the low temperature T1. The temperature is lowered to the phase transition point Ths by being cooled by the fluid. At this time, the temperature of the cooling fluid is T1.

  After the circulating fluid temperature Th reaches the phase transition point, the temperature does not change until the latent heat substance not dissolved in the circulating fluid is completely deposited. Since a large amount of heat corresponding to the latent heat is released when the latent heat substance is deposited, the temperature T of the cooling fluid rises rapidly. When the deposition of the latent heat substance is completed, the circulating liquid is cooled to the cooling fluid at the temperature T2 that has already become very warm and cooled down, and is discharged from the heat exchanger at the temperature Th3. The heat medium cooled to the temperature Th3 discharged from the heat exchanger is a slurry containing fine particles of the deposited latent heat substance. The cooling fluid discharged from the heat exchanger has a temperature T3.

Even in other types of heat exchangers, the change state of the heat medium temperature is almost the same.
In order to effectively utilize the characteristics of the latent heat substance and reduce the circulation amount of the heat medium as much as possible, it is necessary to use a cooling fluid having a temperature lower than the phase transition point, and the larger the temperature difference between the heat medium and the cooling fluid, the more effective. is there.
However, if the circulation amount of the heat medium becomes too small, the flow velocity flowing through the wall of the heat exchanger becomes small, the heat passage coefficient K becomes small, and the heat transfer efficiency decreases. Further, if the tube diameter is reduced to increase the flow velocity, the heat transfer area is reduced and the efficiency is similarly reduced.

  Therefore, as shown in FIG. 3, by inserting the twisted tape 12 into the straight pipe portion, the flow rate of the heat medium near the wall surface is increased, the flow of the heat medium is disturbed, and the heat transfer performance is improved. Further, when the torsion tape 12 is inserted, the heat medium flows spirally and centrifugal force is generated. Therefore, by utilizing the fact that the specific gravity of the latent heat substance involved in the phase transition is heavier than the solvent, the latent heat substance is applied to the tube wall by centrifugal force. By pushing, it is possible to promote the utilization of latent heat in the vicinity of the tube wall and improve the efficiency. Incidentally, while the specific gravity of water is 1 and the specific gravity of ethylene glycol is about 1.12, the specific gravity of alum is larger than that, for example, about 1.75 for potassium alum.

  Although the above explanation relates to the temperature change in the low temperature side heat exchanger, the circulating fluid absorbs heat in the cooling passage of the engine that hits the high temperature side heat exchanger. Since it is based on the same mechanism, it is almost the same except that the temperature change of the circulating fluid is a temperature raising process.

In order to realize such a temperature process, the substantial latent heat expression region of the heat medium containing the latent heat substance is set so that the inlet temperature and the outlet temperature are the same in both the high temperature side heat exchanger and the low temperature side heat exchanger. There must be in between.
Therefore, if the operating temperature range of the heat medium is 40 ° C. to 95 ° C. of a normal engine cooling device, the substantial latent heat absorption region of the heat medium is preferably in the range of 60 ° C. to 90 ° C., for example.

FIG. 7 is a graph plotting the flow rate of the heat medium and the pump power against the amount of the latent heat substance hydrate contained in an insoluble state when the heat medium of the present invention is used. The graph is calculated under the condition that the temperature difference between the inlet and outlet of the cooling water is 5 ° C. for a 100 ps engine.
Since the heat transfer amount of the present invention is extremely large, the required amount is drastically reduced, so that the pump power that is proportional to the cube of the load is further drastically reduced.
For example, when the hydrate content is 20 wt%, the required flow rate is reduced to about 1/3, and the pump power is reduced to 1/20.
As described above, the cooling device of the present invention has extremely high power efficiency and can reduce the size of the pump.

Alum refers to a double salt hydrate represented by MaMc (SO ₄ ) ₂ · 12H ₂ O (where Ma is a monovalent metal (ie, alkali metal) and Mc is a trivalent metal). . The alum solubility decreases geometrically in the order of increasing alkali number sodium, potassium, rubidium, cesium and atomic number. This tendency is due to other trivalent metals such as iron, chromium and vanadium. It is the same even if it changes to manganese.
If the solubility is low, the amount of hydrate to be added may be small, and therefore it is preferable to select an appropriate combination of monovalent metal and trivalent metal in consideration of the amount of latent heat.

The alcohol to be mixed with water is not limited to ethylene glycol, and any alcohol that does not dissolve the latent heat substance and is stable to heat is sufficient.
The resistance reducing agent is not limited to a cationic surfactant such as oleylbishydroxyethylmethylammonium chloride, and it goes without saying that an appropriate one can be selected from known ones according to the composition of the heating medium.

The high-temperature zone cooling device of the present invention can effectively cool a high-temperature heating element such as an automobile engine, a motorcycle engine, a marine engine, and a generator engine by circulating a small amount of heat medium. it can. Since the circulation amount of the heat medium is small, the heat medium pump can also be reduced in size, saving pump power and enabling efficient cooling. Needless to say, the high-temperature region cooling device of the present embodiment can be applied to a high-temperature object other than the engine.
On the contrary, it goes without saying that the same effect can be obtained when used for heating applications such as floor heating.

It is a block diagram which shows the example of the high temperature area cooling device which concerns on this invention. It is a perspective view which shows the example of the low temperature side heat exchanger used for the cooling device of a present Example. It is a partially notched perspective view explaining the structure of the heat exchanger used for a present Example. It is a diagram explaining the solubility of the latent heat substance with respect to the heat medium of a present Example. It is the diagram which measured the latent heat of the heat carrier of a present Example. It is a diagram explaining the temperature change of the heat medium in the heat exchanger of a present Example. It is a diagram which shows the relationship of content of the latent heat substance of this Example, required flow volume, and pump power. It is a block diagram of the conventional engine cooling device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High temperature side heat exchanger 2 Low temperature side heat exchanger 3 Pump 4 Cooling fan 5 Thermostat valve 6 Reservoir tank 7 Water temperature sensor 8 Temperature change of the heat medium in the heat exchanger 1 9 Temperature change of the heat medium in the heat exchanger 2 10 Heat Exchanger 11 Part in which heat medium passage has circular cross section 12 Torsion tape

Claims (10)

A first heat exchanger that exchanges heat with a high-temperature material to be cooled, a second heat exchanger that exchanges heat with a low-temperature fluid, a circulation line and a heat medium for circulating the heat medium through the first and second heat exchangers A piping system formed by a pump and containing in the solvent at least a part of the phase change inorganic substance solidified in the second heat exchanger and liquefied in the first heat exchanger as the heat medium A high-temperature region cooling device characterized by using the prepared solution. The high-temperature region cooling apparatus according to claim 1, wherein the first heat exchanger is an engine wall, and the second heat exchanger is a radiator. The high-temperature zone cooling device according to claim 1 or 2, wherein a mechanism for preventing the heat medium flow from moving straight is provided in at least a part of a pipe through which the heat medium passes in the second exchanger. 4. The high-temperature zone cooling device according to claim 3, wherein the mechanism for preventing the heat medium from moving straight is a torsion tape inserted into the pipe. 5. The high-temperature region cooling apparatus according to claim 1, wherein the phase transition inorganic substance has a phase transition point between 60 ° C. and 120 ° C. when in the heat medium. The high-temperature region cooling device according to any one of claims 1 to 5, wherein the heat medium contains a resistance reducing agent that reduces the flow resistance of the solvent. The heating medium comprises an inorganic hydrate as a phase change inorganic substance, and a mixed solution of water and an alcohol whose solubility in the inorganic hydrate is smaller than water as a solvent that does not dissolve the phase change inorganic substance. The high temperature region cooling device according to any one of claims 1 to 6. The inorganic hydrate is aluminum sulfate fourteen-octadecahydrate _{(Al 2 (SO 4) 3} · 14~18H 2 O), according to claim 7, wherein the alcohol is ethylene glycol High temperature zone cooling device. The high-temperature region cooling device according to claim 7, wherein the inorganic hydrate is a sulfate double salt (alum) of a monovalent cation and a trivalent cation, and the alcohol is ethylene glycol. . The alum is potassium aluminum sulfate dodecahydrate (KAl (SO ₄ ) ₂ · 12H ₂ O), aluminum ammonium sulfate dodecahydrate (Al (NH ₄ ) (SO ₄ ) ₂ · 12H ₂ O), iron It is one of alum hexahydrate (Fe (NH ₄ ) (SO ₄ ) ₂ · 6H ₂ O), and the weight ratio of water and ethylene glycol in the solvent is in the range of 2: 8 to 7: 3. The high temperature region cooling device according to claim 8.

Images