Heat storage materials

Page 1

United States Patent Office 2,726,211 Patented Dec. 6, 1955

for use as heat storage liquids which do not undercool.

Technical grades of these materials may be used in which 2,726,211 event the small quantities of impurities present have the HEAT STORAGE MATERALS effect of lowering the melting point slightly. I prefer a mixture of about equal portions by weight of each acid

Vincent J. Schaefer, Schenectady, N.Y., assignor to Gen and have found that such a mixture solidifies at 116 F. eral Electric Company, a corporation of New York without supercooling. However, the proportions may No Drawing. Application April 29, 1953, vary widely. For example, a mixture of 85% by weight Serial No. 349,985 stearic acid to 15% by weight oleic acid solidifies at 130 O F. A mixture of 30% stearic-70% oleic acids by weight 2 Claims. (C. 252-70) solidifies at 93 F.

Where it is desired to lower the solidification point below that obtainable from a binary mixture diphenyl

This invention relates to heat storage materials par 5 of ether may be added as a third component. The addition 5% to 15% by weight of diphenyl ether will lower the ticularly of the type serving as a heat reservoir from solidification which heat may be drawn as needed for space heating. from 20 F. point of the stearic-oleic acid mixtures by Such heat reservoirs are important in heat pump in contains 5% toto 15% 35 F. A satisfactory ternary mixture by weight diphenyl ether and 30% stallations and other heating arrangements. to 50% by weight oleic acid, the balance consisting of A heat storage reservoir consists of a well insulated tank containing a fluid circulating coil on the interior 20 stearic acid. A preferred heat storage material within this range consists of approximately 10% by weight diphenyl thereof surrounded by heat storage material. The nature ether, of the heat storage material depends upon the service re stearic 40% acid.

by weight oleic acid, and 50% by weight

This mixture solidifies at 95° F. without quirements to be met. In many cases, water is a Satis factory heat storage material. However, for space heat 25 insupercooling.

preparing

No special precautions need be observed these mixtures. They are merely weighed ing purposes the heat content of liquid water is insufficient in the correct proportions and mixed. They are then and the melting point of water is too low to make use of ready for use.

the heat of fusion. For use in space heating reservoirs, While the present invention has been described with certain materials having melting points within the range reference of 90° F. to 130 F. are more satisfactory than water. 30 understoodtothat particular embodiments thereof, it will be Certain inorganic salts which do not undercool seriously those skilled in numerous modifications may be made by the art without actually departing from and remain as a two-phase system are satisfactory for this the invention. Therefore, I aim in the appended claims purpose.

to cover all such equivalent variations as come within the

It is an object of this invention to provide an organic true spirit and scope of the foregoing heat storage material having a melting point, or solidifi 35 What I claim as new and desire todisclosure. secure by Letters cation point, within the range considered desirable for Patent of the United States is:

heat storage material.

It is another object of this invention to provide an to 1.15% A heat storage material consisting essentially of 5% by weight diphenyl ether and 30% to 50% by organic heat storage material which does not undercool weight oleic acid, the balance consisting of stearic acid. or supercool to a serious extent. 2. A heat storage material comprising approximately Briefly stated, in accordance with one of its aspects, 40 10% by weight diphenyl ether, 40% by weight oleic acid, this invention is directed to a heat storage material com and 50% by weight stearic acid. prising a mixture of oleic and stearic acids in which stearic acid is present to the extent of 30% to 90% by weight. In References Cited in the file of this patent addition to this binary system, the invention is also directed 45 UNITED STATES PATENTS to a ternary system in which diphenyl ether is present along with the stearic and oleic acids. 679,972 Kyle ------------------ Aug. 6, 1901 Stearic acid melts at 154 F. Commercial oleic acid 735,941 Burwell -------------- Aug. 11, 1903 melts at a temperature below 57 F. I have found that OTHER REFERENCES mixtures of these two substances in which stearic acid is 50 present to the extent of 30% to 90% by weight have a Chem. Society Journal (1939), pp. 974-980. melting point within the range which makes them desirable J. Soc. Chem. Ind. Japan 37, Suppl. binding (1934),