JPH06116550A - Heat-accumulation agent - Google Patents

Abstract

PURPOSE:To provide a heat-accumulation agent composed of a specific composition, having remarkably improved heat-exchange capacity because of the use of the latent heat generated by phase-transition in addition to its retaining sensible heat, exhibiting high fluidity and free from problem of the line clogging. CONSTITUTION:The heat-accumulation agent is produced by making (i) an oleophilic organic compound exhibiting phase-transition in the objective heat- exchange temperature range absorbed in (ii) an oil-absorbing resin capable of highly absorbing the oleophilic organic compound and dispersing the absorption product in a hydrophilic liquid such as water, brine and ethylene glycol. The component (ii) is e.g. an acrylic resin obtained by the suspension polymerization of 60 pts.wt. of hexadecyl methacrylate, 39 pts.wt. of butyl methacrylate and 1 pt.wt. of divinylbenzene. The component (i) is preferably ntetradecane, n-pentadecane, n-decyl alcohol, myristyl alcohol, etc., from the viewpoint of the utilization of the latent heat because these compounds have definite melting point or definite temperature to cause the phase-transition from solid to liquid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel heat storage agent and a method of using the same. The heat storage agent in the present invention is a heat medium or heat-bearing body containing a kind of water-based or hydrophilic liquid as a main component, and the heat storage agent is accumulated in a heated (or cooled) state and then accumulated by heat exchange. It releases the amount of heat (or the amount of cold energy) that has been generated and gives a heating (or cooling) effect. Therefore, in the case of aiming at the cooling effect, the cold storage heat agent is more accurate, but in the range that can be easily understood below, the cold storage heat agent is also simply referred to as the heat storage agent.

[0002]

[Description of Related Art] To explain the usage form of the heat storage agent, a circuit for circulating the heat storage agent is configured as a closed circuit including a heat storage tank and a heat exchanger, and the heat storage agent is heated (or cooled) in advance in the heat storage tank.
That is, a heating source (or cooling source) is created, and this is sent to a heat exchanger as needed to heat (or cool) the target object.
Is used for. The value of this "heat storage (or cold storage) → use as heating source (or cooling source)" is mainly
It is often said based on the power supply situation in Japan. That is, since the demand for electric swords in the daytime in summer increases due to the spread of air-conditioning and cooling, and the power supply becomes tight, heat is stored (cold heat) using nighttime power that has a margin for power supply, and this is used in the daytime. Is recommended from a national point of view.

In response to this measure, some heat storage agents containing water, brine (calcium chloride aqueous solution, etc.) and ethylene glycol as main components have been proposed, but these conventional heat storage agents have only sensible heat. Was used. That is, for the purpose of air conditioning, the heat storage agent may be cooled and held at about 5 ° C. for cooling and heat exchanged, and about 4 ° C. for heating.
It is only necessary to heat and hold at 0 ° C. for heat exchange, but the conventional heat storage agent uses only the sensible heat that it has in these temperature regions. However, in the above temperature range, if the sensible heat stored therein can be used in addition to the latent heat, the effect or heat exchange capacity of the heat storage agent will be further improved.

[0004]

SUMMARY OF THE INVENTION The heat storage agent of the present invention is an oil-absorbing resin (rubbers) which highly absorbs a hydrophobic or lipophilic organic compound in a main agent which is water, brine, water such as ethylene glycol, or a hydrophilic liquid. (Containing a polymer) is dispersed, and a phase change is caused in the oil-absorbing polymer in a desired heat exchange temperature range (for example, 5 to 10 ° C.) to provide or acquire latent heat (obtains latent heat as a refrigerant). ) It is characterized in that a lipophilic organic compound is absorbed in advance.

First, an oil absorbing resin (polymer containing rubbers) which highly absorbs a hydrophobic or lipophilic organic compound will be described. The term "highly absorbable" as used herein means an absorbency of at least 5 times or more the weight of resin. That is, in terms of PHR, it means 500 PHR or more. The resin of the above concept is commercially available. To explain this with some examples, a polymer obtained by polymerizing a vinyl monomer having a solubility parameter (SP value) of about 9 or less by about 90% by weight or more is described above. It corresponds to the concept.

Specific examples of vinyl monomers having a solubility parameter (SP value) of about 9 or less include (meth) acrylic acid esters of monohydric aliphatic alcohols having 10 or more carbon atoms (hereinafter referred to as A monomers). : For example, decyl (meth) acrylate, dodecyl (meth) acrylate, tetradecyl (meth) acrylate, hexadecyl (meth) acrylate, stearyl (meth) acrylate.

Monomers which can be copolymerized with the A monomer as the main component and the A monomer (hereinafter referred to as the B monomer) include: methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate,
There are esters of (meth) acrylic acid with aliphatic alcohols having 9 or less carbon atoms such as 2-ethylhexyl (meth) acrylate and n-octyl (meth) acrylate.

SP of polymer (resin) obtained by polymerization
A monomer having a hydrophilic group (hereinafter referred to as a C monomer) may be selected as a copolymerization component in a range of about 10 or less: for example, methacrylic acid, acrylonitrile, fumaric acid, hydroxyethyl methacrylate. There is. Furthermore, in order to make the polymer crosslinked or branched,
A small amount of polyfunctional vinyl monomer (hereinafter referred to as D monomer) may be added: for example, divinylbenzene, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate.

As an example of a typical monomer mixture, hexadecyl methacrylate (A monomer) 60 parts by weight butyl methacrylate (B monomer) 39 parts by weight divinylbenzene (D monomer) 1 part by weight, polyvinyl alcohol is used as an emulsifier. A predetermined polymer can be polymerized by a known suspension polymerization used as. Although a spherical powder having a particle size of about 10-300 microns is usually obtained by the polymerization, it may be used in the form of a spherical powder as it is, or the particle shape may be processed to obtain, for example, a sugar-and-rice-shaped angular shape. It may be transformed into In addition, a desired particle diameter may be adjusted by appropriately mixing with a porous other substance or another oil absorbing functional substance and molding. In the present invention, it is desirable that the particle size be about 100 microns or less.

Looking at the monomer composition in relation to the above purpose of use, in the case of heating such that the heat exchange temperature is about 40 ° C., the composition of the A monomer is large, and the A monomer is 80% by weight or more. Is suitable, and for cooling such that the heat exchange temperature is about 5 ° C., it is suitable that the A monomer accounts for 50 to 80 parts by weight.

In addition to the above, "norbornene rubber" (trade name, manufactured by CdF, France. This is obtained by cyclizing ethylene and cyclopentadiene by a Diels-Alder reaction to obtain norbornene, which is then polymerized by ring-opening polymerization. Oil-absorbent rubber known as
It can also be used as a resin). The commercially available products include those in powder form and those impregnated with petroleum oil, and any of them can be used.

Next, the lipophilic organic compound (hereinafter sometimes referred to as an oil agent) to be absorbed in the oil absorbing polymer will be described. In short, if it is insoluble in water, it can be used as the lipophilic organic compound of the present application, that is, an oil agent. Specific examples thereof include petroleum-based paraffin waxes and higher fatty alcohols.
In the adoption, it is one that is highly absorbed by the oil-absorbent resin to be used, and the one that has a clear melting point of the absorbed oil agent (lipophilic organic compound) or the temperature at which the phase changes from solid to liquid is clear. It is appropriate from the standpoint of utilizing latent heat. Specific examples are as follows.

In the case of petroleum-based paraffin, that is, normal paraffin, n-tetradecane (carbon number: 14).
Melting point: 5.5 ° C, n-pentadecane (carbon number: 15).
Melting point: 10.0 ° C, n-eicosane (carbon number: 20).
For other commercially available petroleum-based paraffin waxes (which are produced by dewaxing lubricating oils, wax products are sold by dividing the melting point by 5 ° F). The phase change temperature or the temperature range can be known from the data such as the melting point and the needle penetration temperature.
Among the higher fatty alcohols, n-decyl alcohol (melting point: 6 ° C), myristyl alcohol (melting point: 38 ° C),
Cetyl alcohol (melting point: 49 ° C.) can be mentioned. These can be mixed to adjust the phase change temperature.

[0014]

【Concrete example】

1. Preparation of heat storage agent The above-mentioned acrylic oil-absorbing resin is allowed to absorb 15 times its weight of petroleum wax (having tetradecane as a main component and having a phase change temperature adjusted to 5-10 ° C.) (PH
R = 1500). That is, the petroleum wax in an amount 15 times that of the acrylic resin was kept in a liquid state at 30 to 40 ° C., and the acrylic resin was put in this to absorb the entire amount of the wax. Next, the oil-absorbed resin is added to water (refrigerant main agent) in a weight ratio of 4:
It was dispersed to be 6. The weight ratio of the total amount of oil-absorbed resin to water (or brine or ethylene glycol) is preferably in the range of 2: 8 to 5: 5, for example, about 4: 6. 2. Example in which the above heat storage agent is used as a refrigerant In FIG. 1, reference numeral 1 is a cooling device including a compressor 11, a condenser 12, and a cooling unit 13, and a heat storage agent (refrigerant) A in a heat storage tank 2 is pumped by a pump 3. Cooling unit 13 of the cooling device 1
The heat storage agent is cooled by circulating the heat storage agent.
As mentioned above, it is desirable to utilize night power for this cooling.

When the storage (cold) heat ends and the cooling is carried out by the cold heat of the heat storage agent, the valve is switched, the valve at the upper part of the heat storage tank 2 is opened, and the pump 4 transfers the heat storage agent to the pipe 5.
Sent to the heat exchanger 6 through the heat exchanger 6 and, after passing through the heat exchanger, the return pipe 7
Circulation is performed in a closed circuit that returns to the heat storage tank 2 again via. If the heat exchanger 6 is an air conditioner cooling device, cold air is sent to the air conditioning area by heat exchange. When the heat storage facility is not used, the refrigerant cooled by the cooling unit 13 of the cooling device 1 is directly sent to the heat exchanger 6 via the carrier pipe a.

When the present heat storage agent is used as a heating medium, a heating device is used instead of the cooling device 1 of FIG.
For the purpose of air conditioning and heating, as the oil agent to be absorbed by the oil absorbing resin, one that causes a phase change at a temperature near 40 ° C. may be selected.

[0017]

As an experiment in the practice of the above embodiment, a heat exchanger having a considerably thin tube was used, but there was no trouble such as clogging in the pipe,
The flow was good. This is because the heat storage agent of the present invention is in a state where the solid resin is suspended and dispersed (suspended) in the liquid, but the dispersed particles are fine and the dispersibility is good. The heat storage agent of the present invention not only has sensible heat at the heat exchange temperature, but also latent heat generated (or absorbed) at the time of phase change is added. While the oil-absorbent resin flows,
Since the effect of rubbing the surface of the heat exchange wall is imparted, the laminar flow film near the wall surface, which is an obstacle to heat transfer through the wall surface in heat exchange, is destroyed, and the heat exchange capacity is further improved. The so-called scouring effect is great when the oil-absorbent resin is made into an angular shape such as a gold-rice sugar type. Due to such an improvement in heat exchange efficiency, the results of the experiments conducted by the inventors of the present invention have resulted in an efficiency improvement of about 5 times as compared with the case where only water or brine is used. This result suggests that the cross-sectional area of the heat exchange pipe or the required area for heat exchange can be reduced to 1/5 of that of the conventional case. As a result, in the design of the pipe for heat exchange, the temperature difference between the sending and returning of the heat medium (refrigerant) becomes small, so that the sending pipe and the returning pipe can be double-structured pipes to save the space of the piping. Further, this has an effect that the overall size of the air conditioning equipment can be designed small.

[0018]

[Brief description of drawings]

FIG. 1 is a schematic view of an apparatus for carrying out a cooling method using a heat storage agent of the present invention.

[Explanation of symbols]

 1: Cooling device 2: Heat storage tank 3, 4: Pump 5: Conveying (sending) pipe 6: Heat exchanger 7: Return pipe A: Heat storage agent particles

Claims (3)

[Claims] 1. An oil-absorbing resin that highly absorbs a lipophilic organic compound, which has been made to absorb a lipophilic organic compound that undergoes a phase change in a target heat exchange temperature region in advance, using water, brine,
A heat storage agent characterized by being dispersed in a hydrophilic liquid such as ethylene glycol. 2. A method of keeping the heat storage agent according to claim 1 in a heated or cooled state and heating or cooling it through a heat exchanger. 3. An apparatus for holding the heat storage agent according to claim 1 in a heated or cooled state and heating or cooling it through a heat exchanger.