Patent Number: 6,251,179

Title: Thermally conductive cementitious grout for geothermal heat pump systems

Abstract: A thermally conductive cement-sand grout for use with a geothermal heat pump system. The cement sand grout contains cement, silica sand, a superplasticizer, water and optionally bentonite. The present invention also includes a method of filling boreholes used for geothermal heat pump systems with the thermally conductive cement-sand grout. The cement-sand grout has improved thermal conductivity over neat cement and bentonite grouts, which allows shallower bore holes to be used to provide an equivalent heat transfer capacity. In addition, the cement-sand grouts of the present invention also provide improved bond strengths and decreased permeabilities. The cement-sand grouts can also contain blast furnace slag, fly ash, a thermoplastic air entraining agent, latex, a shrinkage reducing admixture, calcium oxide and combinations thereof.

Inventors: Allan; Marita (Old Field, NY)

Assignee: The United States of America as represented by the Department of Energy

International Classification: C04B 28/00 (20060101); C04B 28/02 (20060101); C09K 8/42 (20060101); C09K 8/46 (20060101); C04B 014/06 (); C04B 014/10 (); C04B 024/20 (); E21B 033/14 ()

Expiration Date: 06/26/2018