A method for extracting and utilizing geothermal energy present in the earth's interior is based on at least one essentially vertical bore hole into the ground, the bottom zone of which is provided with penetrating passages into the surronding rock. A heat-conducting substance is forced into the penetrating passages. At least one supply and one return line for a heat transmission medium is thermally linked with the heat-conducting substance and the surrounding rock. The heat transmission medium is conveyed in a circuit in which part of its heat content is extracted and industrially utilized before reintroducing the fluid into the ground.
The device proposed has a pipe (3) sunk into the Earth's crust and designed to convey to the surface a fluid heated by geothermal energy, possibly in vapor form. The device also has a second, outer, pipe (2) surrounding the conveyor pipe and designed to carry the fluid back into the Earth, as well as an end cap (4) which forms a pressure-tight closure over the end of the outer pipe to prevent the ingress of the surrounding rock, etc., the conveyor pipe being joined to the outer pipe at the bottom, in the region of the closure.
A system for increasing efficiency of a closed-earth-loop heat pump system; for increasing heat pump efficiency by feeding relatively colder water to heat pumps when they operate in a cooling mode; and, in certain aspects, systems for using excess produced heat and/or waste heat generated by an air conditioning system that employs an earth loop heat exchange apparatus, the system having power production apparatus that uses the excess produced heat and/or waste heat from air conditioning apparatus to generate electricity and reduce the heat dissipation load on the earth loop heat exchange apparatus; and, in one aspect, such a system that provides cooling fluid to a fuel cell that produces water and electricity.
A geothermal community loop field which serves as a shared means of heat exchange for a plurality of thermal loads. Heat is exchanged between the ground and a circulating heat exchange fluid in at least one subterranean heat exchanger. Heat is exchanged between each thermal load and the circulating heat exchange fluid by contacting the external heat exchanger of each thermal load with the circulating heat exchange fluid. Flow of the circulating heat exchange fluid between the geothermal community loop field and each thermal load is controlled by a plurality of flow control centers, each servicing one thermal load. The flow control centers provide means for installing additional thermal loads or maintaining existing loads without affecting the operation of the rest of the system. In addition, the flow control centers provide a means for setting the flow rate of heat exchange fluid to each thermal load.
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.
A ground freezing system includes a metal feed pipe for delivering refrigerant to the lower end of a freeze pipe installed in a bore in the ground. The feed pipe is supported on a compression spring which accommodates thermal contraction of the feed pipe while maintaining support of its weight.
