JPH06313689A - Transporting method for latent heat storage medium transporting method for cold heat - Google Patents

Abstract

PURPOSE:To efficiently transport latent heat medium by freezing water- containing spherical particles of highly wet water absorption polymer to be used for a disposable diaper, etc., with low temperature non-water soluble liquid, and transporting them in a mixed phase state. CONSTITUTION:Water-containing spherical particles of highly wet water absorption polymer to be used for a disposable diaper, etc., are frozen with non-water soluble liquid of a liquefied state in a lower temperature range than this freezing temperature, and the frozen particles and the liquid are transported in a liquid state. That is, evaporation heat obtained by evaporating to vaporize refrigerant by an evaporator 7 is used to freeze the particles 9B with transported refrigerant liquid 10 in a refrigerating cycle A to form frozen particles 9C. The particles 9C are supplied to load side heat exchangers 13 via a guide tube 11 by a pump 12 together with the liquid 10, and heat exchanger by a heat exchanger 16. Thus, the polymer is effectively used as latent heat medium, fluidity of the medium is obtained even when this mixing ratio is increased to be efficiently transported.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for transporting a heat storage medium for heat storage, which effectively uses a highly swelling water-absorbing polymer.

[0002]

2. Description of the Related Art Conventionally, when supplying cold heat accumulated in a heat source storage section to a cold heat load section, a sensible heat is supplied using a single fluid. The control is performed by increasing / decreasing the flow rate of the fluid, but the amount of fluid supplied and the heat source reservoir for sensible heat use are necessarily increased. In order to eliminate such drawbacks, a method is used in which ice is stored around the cooling pipes in the ice bank tank to store heat, and the molten cold water is used. Since the transportation uses sensible heat, it is not suitable for long-distance transportation, and in such an ice bank tank heat storage method, there is a limit in the thickness of ice and it takes a long time for freezing and water heat exchange is also unsatisfactory. It is uniform and requires extra power such as an in-tank circulation pump. Further, as described above, the sensible heat of cold water is transported, so that the piping is large and the transport power is also large.

For this reason, in recent years, in district heating / cooling and other cold heat transport systems, a method of transporting cold heat by utilizing a latent heat and a solid-liquid two-phase mixed fluid (for example, a mixed solution of ice and brine) has been widely adopted. It started to come. Further, means for forming ice in the shape of a shappet and transporting it as a heat storage agent together with a refrigerant or ethylene glycol is also currently used in cold regions.

However, even in a cold heat transport system comprising a solid-liquid two-phase mixed fluid using this type of ice, the ice / water ratio of the mixed solution is about 2: 8 in order to secure fluidity for transfer. As a result, the proportion of ice is small and the amount of heat that can be used as heat is small. That is, the IPF (ice mixing ratio) was poor.

That is, if the ice / water ratio of the mixed liquid is increased, in other words, if the ratio of the transport amount liquid that secures the fluidity is decreased, the pressure loss in the transport process becomes large and the transport efficiency decreases, which is proportional to this. As a result, the transport flow rate becomes very small, the transport efficiency drops, and the desired amount of heat cannot be obtained. In addition, ice is likely to close in the bent portion and the valve portion of the transport pipe, and the pipe is likely to be blocked.

On the other hand, if the proportion of ice is reduced in order to prevent such a drawback, the heat storage efficiency is lowered, and as a result, the balance between the two is about 2: 8, and as a result ice However, there is a problem that the heat storage amount that can be used as the heat is small because the ratio of the heat is small. That is, it was pointed out that the IPF was bad.

In order to solve the drawbacks of the prior art, it is an object of the present invention to provide a method for transporting a heat transfer medium which does not deteriorate the fluidity even if the mixing ratio of the heat transfer medium is increased. Another object of the present invention is to provide a method for transporting cold heat that allows the water-containing spherical particles of a highly swelling water-absorbing polymer to be effectively used as a heat storage agent.

[0008]

In order to achieve the technical object, the present invention provides a highly swelling water-absorbing polymer which has been used as a sanitary material such as a paper diaper and a sanitary napkin, or a water-retaining material for agricultural soil. The water-containing spherical particles of the water-absorbing polymer are effectively used to freeze through a water-insoluble liquid that is in a liquefied state in a temperature range lower than the freezing temperature of the particles, and the frozen particles are mixed with the liquid. It is characterized by being transported in a state. In this case, the non-water-soluble liquid may be specifically PAG (polyalkylene glycol) or HCF.
It is preferable to use a CFC-based or other refrigerant such as HFC, or a silicone-based oil or other oil-based liquid, but the use of a water-soluble liquid such as ethylene glycol promotes sticking of frozen particles to each other over time. , Not preferable.

PAGs, lubricating oils, especially silicone oils are oils having a low surface friction resistance, and by imparting hydrophobicity to the surface of frozen granules, the lubricity between fluids, that is, the fluidity is remarkably improved. Therefore, the ratio of frozen granules / liquid for transportation can be increased by that amount, and the transport amount of the heat transfer medium can be increased. Such an action can be easily achieved even if a surfactant is mixed in a refrigerant such as a fluorocarbon used as the non-water-soluble liquid. Further, the specific gravity of the frozen hydrous spherical granules is set to be equal to or larger than the specific gravity of the non-water-soluble liquid, or sand is mixed into the granules to increase the apparent specific gravity, specifically, the specific gravity difference. By setting around 10%, the frozen granules can be uniformly dispersed in the transport liquid without floating on the liquid, and the ratio of frozen granules / transport liquid can be increased accordingly.

[0010]

As the highly swelling water-absorbing polymer used in the present invention, it is preferable to use, for example, a cross-linking special acrylate polymer having a spherical shape with a substantially uniform diameter. In the case of 5 to 1.0 m / mφ, 100
If you absorb double the amount of water, it will take 4 to 7 m / mφ in 10 to 20 minutes.
Swells to a spherical particle size of. Moreover, the particle size is 1.0 to 2.0 m / m.
In the case of absorbing 100 times more water, after 20 to 50 minutes,
Swells to a particle size of 7-10 m / m. And these water-containing polymers have the same shape as water that is completely transparent in water, and their shapes cannot be identified.When scooped up, they become spherical transparent gel-shaped independent water globules, and the water is solidified into a gel. It can be understood. This polymer retains water as a gel-like spherical water-containing granule with almost no change in volume of water in order to retain water 100 times, so that the water in the granule is retained as a non-flowing sphere. By the way, when the particle size is 20 μm to 0.5 m / m, the water absorbing particles are mixed with the medium oil and have good fluidity, and the particles can be directly circulated to the heat exchanger as they are.

Since most of the spherical hydrous granules are water, the spherical hydrous granules are immersed in a lubricating oil, PAG, or HCFC or HFC second-generation chlorofluorocarbon system kept at -5 to -15 ° C below the freezing temperature of water. Or, if the solid water polo is frozen by immersing it in silicone oil at a negative temperature, it becomes spherical frozen granules. The freezing liquid obtained by freezing the granules intervenes between the frozen granules and serves as a lubricant between the granules, and the frozen granules having the same or slightly larger specific gravity difference are contained in the freezing liquid. Since it exists, it does not float and hinder the uniform dispersion. Therefore, in this case, the mixing ratio of the frozen granules and the freezing liquid can be increased from the conventional 2: 8 to 8: 2.

When the transportation distance is short, it is not always necessary to transport the particles in a mixed phase with the frozen granules. For example, the water-containing spherical granules of the highly swelling water-absorbing polymer can be used in a temperature range lower than the freezing temperature of the granules. It may be configured such that it is frozen and stored in the heat storage tank via the non-water-soluble liquid in the liquefied state, and only the cold / hot liquid that has exchanged heat with the frozen granules in the heat storage tank is transported to the load side.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be exemplarily described in detail below with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but are merely illustrative examples. Only. First, the high swelling type water-absorbing polymer used in the examples of the present invention is, for example, as shown in JP-A-62-254842, a water-absorbing polymer containing an alkali salt of acrylic acid obtained by polymerizing a monomer as a high polymer content. It can be obtained by crosslinking the functional polymer with a crosslinking agent having two or more functional groups in the presence of an inorganic substance during azeotropic dehydration, and then drying.

Such a polymer forms a spherical particle having a substantially uniform diameter, and if necessary, non-rusting metallic sand 90 or the like may be used as a core in order to increase the specific gravity. For example, PQ polymer BU-100 manufactured by Osaka Organic Chemical Industry Co., Ltd.
Has an average particle size of 70 to 140 μm, a particle size of 0.3 to 0.5 m / m after 100 times water absorption, and a water absorption speed of about 20 seconds to absorb water and swell into a spherical shape. The particle size of the polymer is, for example, 0.
In the case of 5 to 1.0 m / mφ, absorb 100 times more water,
Swell to a spherical particle size of 4 to 7 m / mφ. Furthermore, if the particle size is 1.0 to 2.0 m / m, absorb 100 times more water
Swells to a particle size of -10 m / m. The particle size, water absorption capacity, water absorption speed, etc. can be appropriately changed. Therefore, it is preferable to appropriately determine the particle size according to the desired water absorption time. Further, fine particles having a particle size of 20 μm to 0.5 m / m immediately become ice-snow-like when water is mixed, and this is frozen and mixed with the oily refrigerant to form a fluidized bed.

FIG. 1 shows granules 9 of the highly swelling water-absorbing polymer.
A represents a state in which it absorbs water about 400 times and becomes spherical hydrous granules 9B, and water is retained in a gel state by the granules 9B, and even if they contact each other, they remain solid and do not melt-bond.
In this case, the non-adhesiveness and the lubricity are further improved by interposing the silicone oil or the like after the water content between the granules 9B.
Then, the polymer hydrated 400 times as described above is frozen and transported by the method shown in FIG.

A in FIG. 2 indicates a refrigeration cycle. In the cycle, the compressor 1 compresses HCFC and HFC refrigerants and then reaches the condenser 2, and is cooled and liquefied by another cooling heat exchanger 3. Refrigerant of the refrigeration cycle, for example, a mixture of water-absorbing polymer spherical particles 9B9 previously hydrated in the evaporator and PAG or other surfactant, for example, entering the evaporator 7 through the liquid pipe 5 and the swelling valve 6, for example, the refrigerant. HcFc
₂₂ and HFc _123a are mixed and filled. As a result, the refrigerant of the refrigeration cycle in the evaporator is -5 to -15 ° C in the evaporator.
Using the heat of vaporization that evaporates into the
The spherical granules 9B9 are frozen through to produce frozen granules 9C.

Then, the frozen granules 9C pass through the pump 12 and the outlet pipe 11 together with the transport refrigerant liquid 10, and then the load side branch pipe 15
From 15 'through the flow agent control valve 14, the load side heat exchange device 1
3 can be conducted to perform heat exchange 16. At this time, the transport refrigerant liquid 10 can supply heat sufficiently to the heat exchange load while receiving heat from the hydrous frozen granules 9B. Also the above 2
About 0 μm to 0.2 m / m can be mixed with the transport refrigerant 10 and flow as a fluidized bed into the heat exchanger together with the direct transport refrigerant.

At this time, since the specific gravity of the frozen granules 9C is set to be about 10% higher than that of the transport liquid by using the metal sand powder 90, the liquid mixture take-out portion 7b is provided at the bottom of the evaporator 7. As a result, it is possible to take out a large blending ratio of the frozen granules 9B together with the transport refrigerant liquid 10 (for example, frozen granules 9B: transport refrigerant liquid = 8: 2). The granules 9B can be uniformly dispersed and transported in the transport liquid 19. FIG. 2 shows an example of a direct freezing system in which a refrigerant of a refrigeration cycle is used as a transport liquid for the transport coolant liquid 10. In this case, the heat exchange efficiency in the evaporator 7 is high, but an appropriate blending ratio is maintained accurately. Things are difficult.

In such a case, it is preferable to use the indirect freezing method shown in FIG. Reference numeral 70 in FIG. 3 denotes an evaporator / reservoir tank in which a heat exchange pipe 23, which circulates the evaporative refrigerant that constitutes the refrigeration cycle, is inserted. Inside the reservoir tank 70 and the water-containing spherical particles 9B.
And the water-insoluble transport liquid are mixed in a mixing ratio of 8: 2 or less, and the refrigerant of the refrigeration cycle A is used as the heat exchange tube 2
Spherical particles 9B through the refrigerant and the transport liquid in the heat exchange tube 23 by utilizing the heat of vaporization that is evaporated to −3 to −15 ° C. in 3
Are frozen to form frozen granules 9C, and the frozen granules 9C together with the transport liquid 19 are pump 12 and outlet pipe 11 as described above.
After that, the heat can be exchanged from the load side branch pipe 15 to the load side heat exchange device 13 via the flow rate control valve 14 for heat exchange 16.

The transport liquid 19 includes silicone oil,
PAG or the like is used, these oils act as lubricants in the gaps of the frozen granules 9B, and a refrigerant is used as the transport liquid 10.
Even in the case of the above embodiment, by mixing these silicone oils, PAGs, etc. gently, these oils cover the surface of the granules 9B to improve the fluidity as a lubricating action, and the frozen granules 9C and the transport liquid. The ratio can be increased up to around 8: 2. In addition to PAG, even when silicone oil is used, the specific gravity can be set to 1.0 or less, which is smaller than water, depending on the composition, thereby eliminating the disadvantage that ice floats due to the difference in specific gravity between water and ice. The transport liquid 19 can be transported with a uniform mixing ratio over the entire region. According to such an embodiment, the silicone oil or PAG serves as a lubricant for the frozen granules 9B to improve the solid flow, and thus the granules 9
The mixing ratio of B can be further increased.

FIG. 4 shows an embodiment of the invention according to claim 5 in which only the transport liquid 19 that has been heat exchanged with the frozen granules 9C is fed when the transport distance is short, and 71 is a heat storage tank which also serves as an evaporator. A heat exchange pipe 20 is attached to the load side feed line 17/11, and a refrigerant (HcFc ₂₂₎ for a refrigeration cycle in which the water-containing spherical particles 9B previously hydrated and a surfactant are mixed in the storage tank 71. , HFc _123a ) are mixed and filled. As a result, the night-time short cycle operation is performed on the evaporator / heat storage tank 71 through the bypass pipe 18 with the night power so that the refrigerant of the refrigeration cycle A in the evaporator / storage tank 71 is -3 to − in the evaporator / storage tank 71. While being evaporated to 15 ° C., the spherical particles 9B are frozen by utilizing the heat of evaporation to make frozen particles 9B. Then, during daytime operation, the pump 12 is driven to bring the heat exchange tube 20 into brine or water 29 therein while making thermal contact with the frozen granules 9C in the evaporator / reservoir 71, and the brine 29 through the outlet tube 11, From the load side branch pipe 15 to the load side heat exchange device 13 via the flow rate control valve 14, heat exchange 16 can be performed. Such an embodiment is effective when performing a time difference operation between night and day.

[0022]

As described above, according to the present invention as set forth in claims 1 to 4, the highly swelling type water-absorbing polymer is effectively utilized as a heat transfer medium to obtain uniform fine particles and spherical particles, and the frictional resistance is improved. It is possible to provide a method for transporting a heat transfer medium that can be reduced and effectively mixes a non-water-soluble liquid as a transport liquid so that the fluidity does not decrease even if the compounding ratio of the heat transfer medium is increased. I can. Further, according to the invention of claim 5, the highly swelling water-absorbing polymer can be effectively used as a heat storage agent to effectively carry out a time difference operation between day and night and transport cold heat over a short distance. It has various remarkable effects.

[Brief description of drawings]

FIG. 1 is a schematic view showing a water absorbing state of a spherical water absorbing polymer according to an example of the present invention.

FIG. 2 is a schematic diagram showing a freeze transport system for spherical water-absorbing polymers according to an example of the present invention, and is a schematic diagram showing an example in which a refrigerant is used as a transport liquid.

FIG. 3 is a schematic diagram showing a freeze transport system for spherical water-absorbing polymers according to an example of the present invention, and is a schematic diagram showing an example in which silicone oil or ethylene glycol is used as a transport liquid.

FIG. 4 is a schematic view showing an embodiment of the invention according to claim 5 in which a spherical water-absorbing polymer is used in the heat storage cool storage means.

[Explanation of symbols]

1 Compressor 7, 70, 71 Evaporator (cumulative storage tank, heat storage tank) 2 Condenser 10 Transport refrigerant liquid 9A, 9B, 9C Water absorbing polymer spherical body 13 Load side heat exchange device 19 Transport liquid (silicone oil or ethylene glycol) ) 29 brine

Claims (5)

[Claims] 1. A water-containing spherical granule of a highly swelling water-absorbing polymer is frozen through a non-water-soluble liquid that is in a liquefied state in a temperature range lower than the freezing temperature of the granule, and the frozen granule is used as the liquid. A method of transporting a heat storage medium for heat storage, characterized by transporting in a multiphase state. 2. The method for transporting a heat storage medium according to claim 1, wherein the non-water-soluble liquid is PAG (polyalkyl glycol), a chlorofluorocarbon-based refrigerant, or a silicone-based oil. 3. The method for transporting a heat storage medium for heat storage according to claim 1, wherein the non-water-soluble liquid has the same or smaller specific gravity than the frozen water-containing spherical particles. 4. The method for transporting a heat storage medium according to claim 1, wherein a surfactant is mixed in a refrigerant such as a chlorofluorocarbon used as the water-insoluble liquid. 5. A frozen hydrated spherical particle of a highly swelling water-absorbing polymer is frozen and stored in a heat storage tank through a non-water-soluble liquid that is in a liquefied state at a temperature range lower than the freezing temperature of the particle. A method for transporting cold heat, which comprises transporting cold / hot liquid that has undergone heat exchange between a body and a heat storage tank to a load side.