JPS59204681A - Solar gel pond - Google Patents

Abstract

PURPOSE:To provide a low-cost solar gel pond of improved heat storage efficiency, by using a water-containing gel prepared by neutralizing, with an acid, salt, etc., an aqueous solution containing an inorganic salt, water-soluble organic polymer, etc. CONSTITUTION:The objective water-containing gel can be obtained by neutralizing an aqueous solution prepared by incorporating water with (A) an alkali (alkaline earth) salt such as sodium silicate, potassium silicate, lithium silicate, and (B) a water-soluble organic polymer such as PVA, cellulosic water-soluble resin, polysaccharide derivative, or plus, (C) Soot or a dye such as Sulfur Black by a neutralizing agent, e.g., chloride from Mg, Ca, Mn, etc., acid metal salt. The concentrations of the components (A) and (B) in said aqueous solution are pref., as follows: (1) for the component (A), 0.1-10wt% calculated as silicate, (2) for the component (B), 0.1-5wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solar pond using colored water gel as a new heat storage material.

A solar bond is a pond that can absorb and store sunlight in the form of heat.

The conventional solar bond heat collection and storage method is to use a salt solution to create a concentration gradient to prevent convection, increase the heat insulation effect, and suppress heat radiation. To form this concentration gradient, fresh water may be injected into the concentrated salt solution, depending on the type and concentration of salt.

A density gradient is formed in accordance with this concentration gradient, and this density gradient prevents the occurrence of a density difference due to a temperature difference, and also prevents the occurrence of convection due to buoyancy. If convection is prevented, heat radiation is suppressed and long-term heat storage becomes possible.

However, the salt water Solarbond has the following drawbacks.

Firstly, since it is a method of forcing fresh water to flow through the salt solution to forcibly form a concentration gradient, it is necessary to have water in the upper layer at all times.

Second, this method requires several months to build up the saline gradient and initiate heat storage. Thirdly, it causes salt damage due to water leakage, so it cannot be used in situations where salt damage is fatal, such as fish incubation or aquaculture. Fourthly, salt water cannot be used economically except for salt, which must be at least 20% salt. Sixth, the amount of heat stored is expressed by the product of specific heat, temperature, and mass, and the specific heat of water is the largest, so water has the largest amount of heat for the same mass at its radiation temperature. Generally, salts have a small specific heat, and the specific heat of a salt solution decreases as the specific gravity of the solution increases, so the amount of heat of a highly concentrated salt solution of the same mass at the same temperature decreases. Therefore, it can be said that concentrated salt water Solarbond is inefficient.

Seventh, if algae, mud, or sand is mixed in, the large amount of concentrated saline water can cause salt damage and cannot be dumped.

The present invention has been made in consideration of the various drawbacks mentioned above, and as a result of intensive research into a heat storage material for solar ponds that can collect and store a large amount of heat, the present invention has achieved the objective by using a gel-like substance as a completely new heat storage material for solar ponds. The present invention was developed based on this finding.

The present invention provides a heat storage material that is significantly improved over water solar bond.

The heat storage material of the present invention will be described in more detail.

First, the raw silicates, sodium silicate, potassium silicate, and lithium silicate, may be in the form of a powder or a concentrated solution (candy-like). Examples of water-soluble organic polymer resins include cellulose-based celluloses such as caleboxymethyl heptalurine, hydroxyproylcellulose, hydroxymethylcellulose, and methylcellulose, polysaccharide derivatives such as amylose, hydroxyethyl polyacrylate, and polyacrylic acid. and its salts, polyacrylic acid and its salts, polyvinylhydrolidone, and polyvinyl alcohol, all of which mix well with silicate to form a uniformly colored water gel. Salts as neutralizing agents include chlorides such as magnesium chloride, calcium chloride, and aluminum chloride, or nitrates such as magnesium nitrate, calcium nitrate, and aluminum nitrate, or sulfates such as magnesium sulfate, calcium sulfate, and aluminum sulfate, or magnesium acetate. , acetates such as calcium acetate, aluminum acetate, and other acids, such as organic salts such as magnesium citrate, calcium citrate, macnesium tartrate, and calcium tartrate. Gels are formed with any of the above salts. Acids used as neutralizing agents include hydrochloric acid, sulfuric acid, nitric acid, acetic acid, succinic acid, citric acid, and fumaric acid.

The reaction conditions for gel production and the optimal conditions for use as a heat storage material are as follows: After dissolving the silicate, a water-soluble organic polymer resin is added to completely dissolve the gel, and then the gel is neutralized with acid or salt. For example, a so-called colored water gel containing a large amount of water is produced, but it is better to add a water-soluble organic polymer resin than a colored water gel containing silicate alone, even if the silicate content is small. is produced, the transparency is improved, and the light absorption efficiency is improved. Economically, it is desirable to have a concentration of the silicate and the water-soluble organic polymer resin such that the gel contains a large amount of water and no fluidity occurs. The optimum concentration of silicate usually used is 0.7% to 70%, and the optimum concentration of water-soluble organic polymer resin is 0.7% to 5%.

The concentration and amount of neutralizing conditions vary depending on the type of acid, salt, etc., but the usual neutralizing conditions are suitable when the hydrogen ion concentration is between 1 and 2. The so-called gelation time when a solution becomes gel-like is determined by the degree of hydrogen ion a, but for example, a solution of 2s% sodium silicate and 3% polyvinyl alcohol at 20°C is heated to a hydrogen ion concentration of 70% with 50% sulfuric acid. When neutralized, gelation begins in 7 hours and is completed in 2 to 3 hours. In the case of aluminum carrier, which is a salt, gelation occurs immediately upon addition of sodium silicate-polyvinyl alcohol. The acids and salts used for gelation can be selected according to the required gelation rate, and a large amount of colored water gel can be easily produced. Furthermore, using ink or black dye will further increase light absorption.

The colored water gel produced by the above method has a low concentration of silicate and water-soluble organic polymer resin, so it can be easily transported as a heat storage material, and since the colored water gel produced is neutral, water leaks from the bond. However, it is completely harmless.

Colored water gel holds a large amount of water with a small amount of silicate and a water-soluble organic polymer resin, which prevents water convection and suppresses heat radiation, allowing heat to be stored effectively. In addition, the specific heat, which is a measure of the amount of heat, is small because a small amount of silica salt is used in a large amount of water.If the amount of heat is the same at the same temperature and the same material, colored water gel bond will accumulate a much higher amount of heat. There will be.

The above features are the most advantageous features of the present invention.

Next, the present invention will be explained in detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded.

Example/ ,! After dissolving S2 powdered sodium silicate in 933 yd of water, adding 2y of polyvinyl alcohol and dissolving it uniformly, a solution of S2's sulfuric acid dissolved in 20ml of water was added to the silicate powder. Pour 73-0 diluted solution into sodium solution, and after about 7 hours, the solution will begin to gel, and after 3 hours, the solution will start to gel. 230 ml of water was injected to make a ratio of gel phase and aqueous phase to /l. On the other hand, 750 ml of 2s% sodium chloride was poured into the same /l thermos flask, and 230d of water was gently added to make the volume /l.

I placed three thermos flasks directly under the soowtvp ungsten light bulb. The distance between the bulb and the thermos is 300 mm from the opening of the thermos to the bulb glass surface, and the amount of light measured by the pyranometer is 0. fOri cal-c1++ -#lln.

The temperature was measured by installing a thermocouple at a distance of /Q mm from the opening of each thermos flask and using a recorder. The light irradiation was made to be almost the same as the solar radiation by repeatedly turning on a light bulb for an hour Q and turning it off for /g hours. When we measured this extinction process over a long period of time, we found that when comparing the temperature rise of colored water gel and common salt, the colored water gel always maintained a higher temperature than the common salt. In other words, the minimum temperature of the highest temperature immediately after lighting the otsu hour is 5.2 °C higher for the colored water gel, and the maximum temperature after 73 hours is g, S higher for the colored water gel.
A high value of oC was also obtained.

Claims (1)

[Claims] l) A mixed solution of an inorganic salt and a water-soluble organic polymer or an aqueous solution to which a dye is added, using seven or more types of alkaline salts and alkaline earth salts among acids and salts. A colored water gel solar pond according to claim 1. 3) The water-soluble organic polymer contained in the colored water gel, sitefoli vinyl alcohol, carboxymethyl celerose,
Hydroxypropylcellulose/recellulose, methylcellulose cellulose water-soluble resin,
Claim 1 describes the use of seven or more types of polysaccharide derivatives such as amylose, hydroxyethyl polyacrylate, polymethacrylic acid and its salts, polyacrylic acid and its salts, and polyvinylpyrrolidone. colored water gel solar bond. 4) Acids used as neutralizing agents for inorganic salts that produce colored water gels include hydrochloric acid, sulfuric acid, nitric acid, or organic acids such as acetic acid, succinic acid, citric acid, and fumaric acid, and seven or more of these are used. A colored water gel solar pond according to claim 1. The colored water gel solar pond according to claim 1, which uses seven or more acid metal salts of organic acids such as acetic acid, fumaric acid, citric acid, and succinic acid. 6) The package according to claim 1, wherein the dye contained in the colored water gel is seven or more of black coloring dyes such as ink, sulfur black, diamond black, and naphtho-7rebrak. Water gel solar pond.