Subterranean continuous loop heat exchanger, method of manufacture and method to heat, cool or store energy with same

Abstract

A subterranean continuous loop heat exchanger is disclosed having a borehole including an entrance at a first end and an exit at a second end and a conduit for a fluid. A direction of fluid flow relative to the borehole is unidirectional, and a major length of the borehole is non-horizontal. The entrance and the exit are separated by a predetermined distance and a first thermal envelope at the entrance and a second thermal envelope at the exit are substantially independent. The conduit is positioned in at least a portion of the borehole and in operational connection to supply and return lines for connection to a ground sourced heat pump or to a heat exchanger system. Also disclosed are methods of constructing a subterranean continuous loop heat exchanger having at least one continuous borehole and a method of regulating a temperature in a structure with a system that includes the subterranean continuous loop heat exchanger.

1 . A subterranean continuous loop heat exchanger, comprising:
 a borehole including an entrance at a first end and an exit at a second end;   a conduit for a fluid, the conduit positioned in at least a portion of the borehole and in operational connection to a supply line and to a return line for connection to a ground sourced heat pump or a heat exchanger system;   wherein the entrance and the exit are separated by a predetermined distance and a first thermal envelope of the borehole at the entrance and a second thermal envelope of the borehole at the exit are substantially independent,   wherein a direction of fluid flow relative to the borehole is unidirectional, and   wherein a major length of the borehole is non-horizontal.   
     
     
         2 . The subterranean continuous loop heat exchanger of  claim 1 , comprising a heat exchange medium positioned within an annulus (preferably the entire annulus) between an inner wall of the borehole and an outer surface of the conduit, the heat exchange medium contributing to a thermal exchange with a surrounding strata. 
     
     
         3 . The subterranean continuous loop heat exchanger of  claim 1 , wherein the conduit can include a flow enhancement feature placed in a fluid flow stream within the conduit. 
     
     
         4 . The subterranean continuous loop heat exchanger of  claim 3 , wherein the turbulence feature includes a plurality of ribs on an inner surface of the conduit. 
     
     
         5 . The subterranean continuous loop heat exchanger of  claim 4 , wherein the flow enhancement feature includes a raised profile on one or more of an inner surface of the conduit. 
     
     
         6 . The subterranean continuous loop heat exchanger of  claim 3 , wherein the flow enhancement feature includes an insert positioned within the conduit. 
     
     
         7 . The subterranean continuous loop heat exchanger of  claim 6 , wherein the insert has a spiral shape or a helical shape. 
     
     
         8 . The subterranean continuous loop heat exchanger of  claim 6 , wherein the insert is a twisted ribbon of metal, metal alloy or a synthetic material. 
     
     
         9 . The subterranean continuous loop heat exchanger of  claim 1 , wherein the conduit includes a raised profile on one or more of an outer surface of the conduit and an inner surface of the conduit. 
     
     
         10 . The subterranean continuous loop heat exchanger of  claim 1 , comprising a plurality of conduits for a fluid, each conduit positioned in at least a portion of the subterranean borehole and in operational connection to the supply line and to the return line for connection to the ground sourced heat pump or to the heat exchanger system. 
     
     
         11 . The subterranean continuous loop heat exchanger of  claim 1 , wherein the conduit is a tube or pipe formed from a metal, a metal alloy or a synthetic material. 
     
     
         12 . The subterranean continuous loop heat exchanger of  claim 1 , wherein operational connection of the conduit to the supply line and to the return line includes a header system. 
     
     
         13 . The subterranean continuous loop heat exchanger of  claim 1 , wherein the predetermined distance is at least about fifteen feet. 
     
     
         14 . The subterranean continuous loop heat exchanger of  claim 1 , wherein the predetermined distance is between about one foot and about five feet. 
     
     
         15 . The subterranean continuous loop heat exchanger of  claim 1 , wherein the predetermined distance is based on a thermal capability of the strata containing the heat exchanger and a load requirement of a structure, a temperature of which is to be regulated by the ground source heat pump or by the heat exchanger system. 
     
     
         16 . The subterranean continuous loop heat exchanger of  claim 1 , comprising a plurality of boreholes, wherein the conduit is positioned in series in the plurality of boreholes. 
     
     
         17 . The subterranean continuous loop heat exchanger of  claim 1 , comprising a plurality of boreholes, wherein the conduit is positioned in parallel in the plurality of boreholes. 
     
     
         18 . The subterranean continuous loop heat exchanger of  claim 1 , wherein at the entrance of the borehole and at the exit of the borehole, a centerline of the borehole is within ±15 degrees of vertical. 
     
     
         19 . The subterranean continuous loop heat exchanger of  claim 18 , wherein at the entrance of the borehole and at the exit of the borehole, the centerline of the borehole is within ±5 degrees of vertical. 
     
     
         20 . A method of constructing a subterranean continuous loop heat exchanger, the subterranean continuous loop heat exchanger including at least one continuous borehole, the method comprising:
 forming a borehole by boring into a strata;   positioning a conduit for a fluid in at least a portion of the borehole; and   operationally connecting the borehole to a supply line and to a return line for connection to a ground sourced heat pump or a heat exchanger system;   wherein a first opening of the borehole and a second opening of the borehole are separated by a predetermined distance and a first thermal envelope of the borehole at the first opening and a second thermal envelope of the borehole at the second opening are substantially independent,   wherein a direction of fluid flow relative to the borehole is unidirectional, and   wherein a major length of the borehole is non-horizontal.   
     
     
         21 . The method of  claim 20 , wherein forming the borehole by boring into the strata includes boring a first portion of the borehole from the first opening and boring a second portion of the borehole from the second opening to join the second portion to the first portion to form the continuous borehole. 
     
     
         22 . The method of  claim 21 , wherein a guiding device assists in boring the second portion to join the first portion, wherein the guiding device includes one or more of a beacon located in the first portion and a sensor in the second portion, the sensor in operational contact with a sensor monitor, and wherein an output from the sensor monitor is used to guide the boring of the second portion to join the first portion. 
     
     
         23 . The method of  claim 22 , wherein the guiding device uses a radio frequency, electric or mechanical signal, a magnetic field or an acoustic signal. 
     
     
         24 . The method of  claim 20 , wherein positioning the conduit includes positioning a conduit in the first portion of the borehole through the first opening and pulling the conduit toward the second opening into the second portion of the borehole. 
     
     
         25 . The method of  claim 20 , wherein positioning a conduit at the point at which the drilling media exits the earth and includes operationally attaching a conduit to the drilling media and pulling the conduit towards the first opening of the borehole. 
     
     
         26 . The method of  claim 20 , comprising positioning a heat exchange medium within an annulus between an inner wall of the borehole and an outer surface of the conduit, the heat exchange medium contributing to a thermal exchange with a surrounding strata. 
     
     
         27 . The method of  claim 20 , wherein the conduit includes a flow enhancement feature placed in a fluid flow stream within the conduit. 
     
     
         28 . The method of  claim 27 , wherein the flow enhancement feature includes a raised profile on one or more of an inner surface of the conduit. 
     
     
         29 . The method of  claim 20 , wherein the conduit includes a raised profile on one or more of an outer surface of the conduit and a raised profile on an inner surface of the conduit. 
     
     
         30 . The method of  claim 20 , wherein at the entrance of the borehole and at the exit of the borehole, a centerline of the borehole is within ±15 degrees of vertical. 
     
     
         31 . A method of regulating a temperature in a structure, the method comprising:
 flowing a fluid through a conduit in a borehole of a subterranean continuous loop heat exchanger from an entrance to an exit;   flowing the fluid from the exit through a ground sourced heat pump or a heat exchanger system;   returning the fluid from the ground sourced heat pump or from the heat exchanger system to the entrance; and   operating the ground sourced heat pump or heat exchanger system to regulate the temperature in the structure.   
     
     
         32 . The method of  claim 31 , wherein the conduit is positioned in at least a portion of the borehole and in operational connection to a supply line and to a return line for connection to the ground sourced heat pump or to the heat exchanger system and wherein the entrance and the exit are separated by a predetermined distance and a first thermal envelope of the borehole at the entrance and a second thermal envelope of the borehole at the exit are substantially independent. 
     
     
         33 . The method of  claim 31 , wherein a direction of flow of the fluid relative to the borehole is unidirectional, and wherein a major length of the borehole is non-horizontal 
     
     
         34 . A method to store thermal energy in a subterranean continuous loop heat exchanger, the method comprising:
 flowing a fluid through a conduit in a borehole of a subterranean continuous loop heat exchanger from an entrance to an exit;   flowing the fluid from the exit through a ground sourced heat pump or a heat exchanger system;   returning the fluid from the ground sourced heat pump or from the heat exchanger system to the entrance; and   operating the ground sourced heat pump or the heat exchanger system to exchange thermal energy with a strata surrounding the subterranean continuous loop heat exchanger.   
     
     
         35 . The method of  claim 34 , wherein the conduit is positioned in at least a portion of the borehole and in operational connection to a supply line and to a return line for connection to the ground sourced heat pump or to the heat exchanger system and wherein the entrance and the exit are separated by a predetermined distance and a first thermal envelope of the borehole at the entrance and a second thermal envelope of the borehole at the exit are substantially independent. 
     
     
         36 . The method of  claim 34 , wherein a direction of flow of the fluid relative to the borehole is unidirectional, and wherein a major length of the borehole is non-horizontal.