Vertical heat exchanger for a geothermal heating and cooling system and method of use

A ground source heat exchanger (110) is described herein, The ground source heat exchanger (110) including: a first fluid conduit (112), the first fluid conduit having a first arcuate configuration with a first plurality of separate passages (114) extending therethrough; a second fluid conduit (116), the second fluid conduit having a second arcuate configuration with a second plurality of separate passages (118) extending therethrough; and an end cap (120) secured to a distal end (122) of the first fluid conduit and a distal end (124) of the second fluid conduit, wherein the end cap fluidly couples the first plurality of separate passages of the first fluid conduit to the second plurality of separate passages of the second fluid conduit, wherein the first fluid conduit and the second fluid conduit when secured to the end cap define an internal cavity (126) extending through the ground source heat exchanger.

BACKGROUND

Exemplary embodiments of the present disclosure pertain to the art of geothermal heating and cooling systems and components thereof.

In a geothermal heating and cooling system heat exchangers are inserted into the ground. The heat exchangers are configured to transfer fluid into and out of the ground in order to operate the system.

Accordingly, it is desirable to provide heat exchangers that optimize the surface area of the heat exchanger in order improve the efficiency of the heat exchanger.

BRIEF DESCRIPTION

A ground source heat exchanger is described herein, The ground source heat exchanger including: a first fluid conduit, the first fluid conduit having a first arcuate configuration with a first plurality of separate passages extending therethrough; a second fluid conduit, the second fluid conduit having a second arcuate configuration with a second plurality of separate passages extending therethrough; and an end cap secured to a distal end of the first fluid conduit and a distal end of the second fluid conduit, wherein the end cap fluidly couples the first plurality of separate passages of the first fluid conduit to the second plurality of separate passages of the second fluid conduit, wherein the first fluid conduit and the second fluid conduit when secured to the end cap define an internal cavity extending through the ground source heat exchanger.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the ground source heat exchanger further includes: a first transition located at a proximal end of the first fluid conduit, the first transition fluidly coupling the first plurality of separate passages to an opening of the first transition.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the ground source heat exchanger further includes: a second transition located at a proximal end of the second fluid conduit, the second transition fluidly coupling the second plurality of separate passages to an opening of the second transition.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the second plurality of separate passages are greater than the first plurality of separate passages.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the end cap has an outer periphery and the first fluid conduit has an outer periphery and the second fluid conduit has an outer periphery, wherein the outer periphery of the first fluid conduit and the outer periphery of the second fluid conduit define an outer periphery of the ground source heat exchanger when the first fluid conduit and the second fluid conduit are secured to the end cap, and wherein the outer periphery of the ground source heat exchanger is not greater than the outer periphery of the end cap.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, wherein the first fluid conduit has an outer periphery and the second fluid conduit has an outer periphery, wherein the outer periphery of the first fluid conduit and the outer periphery of the second fluid conduit define an outer periphery of the ground source heat exchanger when the first fluid conduit and the second fluid conduit are secured to the end cap, and wherein the outer periphery of the second fluid conduit is greater than the outer periphery of the first fluid conduit.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, wherein the end cap has an opening extending therethrough the opening being in fluid communication with the internal cavity when the first fluid conduit and the second fluid conduit are secured to the end cap.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, wherein at least the first fluid conduit and the second fluid conduit are formed from high-density polyethylene.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, wherein the first fluid conduit has an inner periphery and the second fluid conduit has an inner periphery each being spaced from each other when the first fluid conduit and the second fluid conduit are secured to the end cap.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, wherein the first fluid conduit has a kidney shape and the second fluid conduit has a semi-circular shape.

Also disclosed is a geothermal system. The geothermal system including: a plurality of vertical heat exchangers in fluid communication with a heat pump via at least one supply conduit and at least one return conduit, wherein each of the plurality of vertical heat exchangers include: a first fluid conduit, the first fluid conduit having a first arcuate configuration with a first plurality of separate passages extending therethrough; a second fluid conduit, the second fluid conduit having a second arcuate configuration with a second plurality of separate passages extending therethrough; and an end cap secured to a distal end of the first fluid conduit and a distal end of the second fluid conduit, wherein the end cap fluidly couples the first plurality of separate passages of the first fluid conduit to the second plurality of separate passages of the second fluid conduit, wherein the first fluid conduit and the second fluid conduit when secured to the end cap define an internal cavity extending through the ground source heat exchanger.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, each of the plurality of vertical heat exchanges include: a first transition located at a proximal end of the first fluid conduit, the first transition fluidly coupling the first plurality of separate passages to an opening of the first transition.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, each of the plurality of vertical heat exchanges include: a second transition located at a proximal end of the second fluid conduit, the second transition fluidly coupling the second plurality of separate passages to an opening of the second transition.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the second plurality of separate passages are greater than the first plurality of separate passages.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the end cap has an outer periphery and the first fluid conduit has an outer periphery and the second fluid conduit has an outer periphery, wherein the outer periphery of the first fluid conduit and the outer periphery of the second fluid conduit define an outer periphery of the ground source heat exchanger when the first fluid conduit and the second fluid conduit are secured to the end cap, and wherein the outer periphery of the ground source heat exchanger is not greater than the outer periphery of the end cap.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the first fluid conduit has an outer periphery and the second fluid conduit has an outer periphery, wherein the outer periphery of the first fluid conduit and the outer periphery of the second fluid conduit define an outer periphery of the ground source heat exchanger when the first fluid conduit and the second fluid conduit are secured to the end cap, and wherein the outer periphery of the second fluid conduit is greater than the outer periphery of the first fluid conduit.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the end cap has an opening extending therethrough the opening being in fluid communication with the internal cavity when the first fluid conduit and the second fluid conduit are secured to the end cap.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, at least the first fluid conduit and the second fluid conduit are formed from high-density polyethylene.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the first fluid conduit has an inner periphery and the second fluid conduit has an inner periphery each being spaced from each other when the first fluid conduit and the second fluid conduit are secured to the end cap.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the first fluid conduit has a kidney shape and the second fluid conduit has a semi-circular shape.

Also disclosed herein is a method of installing a ground source heat exchanger of a geothermal system below ground level. The method including the steps of: securing a first fluid conduit to a second fluid conduit via an end cap to create the ground source heat exchanger, wherein the first fluid conduit has a first arcuate configuration with a first plurality of separate passages extending therethrough and the second fluid conduit has a second arcuate configuration with a second plurality of separate passages extending therethrough, and wherein the end cap is secured to a distal end of the first fluid conduit and a distal end of the second fluid conduit, wherein the end cap fluidly couples the first plurality of separate passages of the first fluid conduit to the second plurality of separate passages of the second fluid conduit, wherein the first fluid conduit and the second fluid conduit when secured to the end cap define an internal cavity extending through the ground source heat exchanger; inserting the ground source heat exchanger into a borehole; and filling the internal cavity with grout after the ground source heat exchanger has been inserted into the borehole.

DETAILED DESCRIPTION

A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.FIGS. 1 and 1Aare schematic illustrations of a geothermal system10in accordance with one non-limiting embodiment of the present disclosure. Here a plurality of vertical heat exchangers or heat exchanger assemblies110are located in the earth14surrounding a structure16, which in one embodiment may be a residential home. The plurality of vertical heat exchangers110are in fluid communication with a heat pump18via at least one supply conduit20and at least one return conduit22.

The heat pump is operably coupled to a heating and ventilating system24comprising a plurality of conduits (supply and/or return)26located throughout the structure16.

FIGS. 2A-2Care assembled, exploded and sectional views of a vertical heat exchanger110in accordance with an embodiment of the present disclosure. Referring now toFIGS. 2A-3, a ground source heat exchanger or heat exchanger assembly110is illustrated. The ground source heat exchanger110has a first fluid conduit or supply conduit112. The first fluid conduit or supply conduit112has a first arcuate configuration with a first plurality of separate passages114extending therethrough. The ground source heat exchanger110also includes a second fluid conduit or return conduit116. The second fluid conduit or return conduit116has a second arcuate configuration with a second plurality of separate passages118extending therethrough. Each ground source heat exchanger110further includes an end cap120secured to a distal end122of the first fluid conduit112and a distal end124of the second fluid conduit116. The end cap120fluidly couples the first plurality of separate passages114of the first fluid conduit112to the second plurality of separate passages118of the second fluid conduit116. This fluid flow is illustrated by arrows115inFIG. 2C. The first fluid conduit112and the second fluid conduit116when secured to the end cap120define an internal cavity126extending through the ground source heat exchanger110.

The heat exchanger110also includes a first transition128located at a proximal end130of the first fluid conduit112, the first transition128fluidly couples the first plurality of separate passages114to an opening132of the first transition128. The heat exchanger110also includes a second transition134located at a proximal end136of the second fluid conduit116, the second transition134fluidly couples the second plurality of separate passages118to an opening138of the second transition134.

In one embodiment, the number of the second plurality of separate passages118are greater than the number of the first plurality of separate passages114. As illustrated in the FIGS., the end cap120has an outer periphery140and the first fluid conduit112has an outer periphery142and the second fluid conduit116has an outer periphery144. In one embodiment, the outer periphery142of the first fluid conduit112and the outer periphery144of the second fluid conduit116define an outer periphery of the ground source heat exchanger110when the first fluid conduit112and the second fluid conduit116are secured to the end cap120. In one embodiment, the outer periphery of the ground source heat exchanger110is not greater than the outer periphery140of the end cap120.

In one non-limiting embodiment, the outer periphery144of the second fluid conduit116is greater than the outer periphery142of the first fluid conduit112. As illustrated and in one embodiment, the end cap120has an opening150extending therethrough the opening150being in fluid communication with the internal cavity126when the first fluid conduit112and the second fluid conduit116are secured to the end cap120.

In one non-limiting embodiment, the first fluid conduit112and the second fluid conduit116are formed from high-density polyethylene. Of course, other materials are considered to be within the scope of various embodiments of the present disclosure.

Also shown is that the first fluid conduit112has an inner periphery146and the second fluid conduit116has an inner periphery148each being spaced from each other when the first fluid conduit112and the second fluid conduit116are secured to the end cap120. Also shown and in one non-limiting embodiment, is that the first fluid conduit112has a kidney shape and the second fluid conduit116has a semi-circular shape. Of course, other configurations are considered to be within the scope of various embodiment of the present disclosure.

The heat exchanger110may be used to construct GeoExchange fields that are coupled with ground source heat pumps used in HVAC and hot water generating systems for residential, commercial and industrial applications. In configurations that require more robust materials, it can be used to extract heat from the Earth's crust at temperatures and pressures as required to generate electricity.

The heat exchanger110is engineered to maximize the contact surface area of the heat exchanger110with the borehole wall into which the heat exchanger110is installed. The configuration of the heat exchanger110maximizes the separation distance and the insulation between the supply and return conduits, which can be either the first fluid conduit112or the second fluid conduit116. The disclosed configuration is engineered to more efficiently utilize the lower portion of the borehole than typical heat exchangers. As used herein the lower portion of the borehole refers to areas in which the end cap120and portions of the first fluid conduit or supply conduit112and the second fluid conduit or return conduit116proximate to the end cap120are located in the borehole. The heat exchanger110is designed to minimize parasitic losses due to the interaction between the supply and return conduits. It is designed to resist collapse due to formation and grout pressures at depths greater than are achievable using conventional heat exchangers.

In one embodiment and when installing a GeoExchange field using the heat exchangers110disclosed herein, total drilling can be reduced by over ⅔ compared to using a conventional vertical heat exchanger.

In the below example a commercial computer assisted GeoExchange field design software package was used to compare use of heat exchangers110versus U-bend (1¼″) heat exchanger. The below example shows the total reduction in quantity of vertical heat exchangers required by using heat exchangers110instead of U-bend (1¼″) heat exchangers. Therefore, the reduction in the field footprint is directly related to the properties of the formation and the balance of the heat gain and loss of the structure. In the below example, the required drilling can be reduced by as much as 70% depending on the building loads, use, and hours of operation.

The below example uses the following variable inputs into a commercial computer assisted GeoExchange field design software package modified to compensate for the short term effect difference between U-bend heat exchangers and using heat exchangers110.

Example based on actual load calculations and formation properties.

Identical inputs for the formation and load conditions for a recent residential development:

This design was completed with 95° F. considered to the maximum design cutoff temperature and 30° F. to be the minimum design cutoff temperature. Comparative Results using U-bend and heat exchanger110:

Convection heat transfer is fundamentally a time-at-temperature process, hence return conduit Reynolds number (Re) dependent, with actual magnitude exchange surface area dependence. The heat exchanger110design maximizes available exchange surface area in comparison, and the reduced return conduit Re increases time-at-temperature, both fundamental first principles of impact on thermal exchange improvement compared to other geothermal heat exchangers.

One key measurable factor of heat exchanger110performance, in comparison to a U-bend with comparable flow performance, occurs in the first tens of hours of installation startup. Readily apparent is the factor of 4 increase in time required for the heat exchanger110LWT to reach the design cutoff compared with the U-bend. This distinction is directly Re optimization+ extreme exchange surface area intrinsic to heat exchanger110.

One additional fundamental factor that determines the comparison results between heat exchanger110and other heat exchangers is the formation thermal conductivity and diffusivity. Both a greater thermal conductivity and lesser thermal diffusivity produce larger differences in the comparisons. The effects are cumulative.

Using the comparative analysis above, the total length of a one row GeoExchange U-bend field with bores spaced at 25′ would be 3,650 feet compared to 1,100 feet for heat exchanger110, a 70% reduction in linear space. Comparing a field constructed with147U-bend bores in a 21×7 configuration, 75,000 sq. ft. with a heat exchanger110field of 56 bores in an 8×7 configuration or 26,250 sq. ft. results in a 65% reduction in area.

As such, the heat exchanger110can reduce the footprint of a field by over ⅘ when compared to the area required for a field constructed with conventional vertical heat exchangers. The systems disclosed herein are closed loop systems that offer maximum efficiency compared to existing technologies with no significant adverse impact on the environment.

As illustrated, the heat exchanger110has separate transitions caps128,134for the supply and return conduit casings. In one embodiment, the transitions caps128,134are fused with the first and second fluid conduits112,116while the end cap120is designed to also fuse with the specific conduit casing (e.g., first and second fluid conduits112,116). In one embodiment, the transitions caps128,134are configured to minimize pressure drop due to turbulence.

The configuration of the heat exchanger110also simplifies grout tube insertion during installation of the heat exchanger110into the soil, which reduces labor costs. By providing separate conduit casings112,116to house the supply and return conduits114,118a pathway126for the grout tube is provided without extruding a specific conduit for grout. In other words, opening126serves as the pathway for the grout tube.

In accordance with various embodiment of the present disclosure, the heat exchanger110disclosed herein reduces the material required for construction of heat exchangers110and expands the area available for encased fluid conduits. The configuration of the first and second fluid conduits112,116allows the conduits to be coiled for storage and installation.

In addition and by providing the internal cavity126the heat exchanger110allows grout to fill the annular space outside of the supply and return conduits112,116and the space or cavity126in between the supply and return conduits112,116. Also, the configuration of the heat exchanger110allows both conduit sets to make contact with the formation of the wall the heat exchanger110is inserted into.

In one embodiment, the end cap120is configured to fuse the two conduit casings112,116into a single system and the end cap120defines the diameter of the borehole reducing the annular space between the borehole walls and an exterior surface of the supply and return conduits112,116to a minimum. Also and by incorporating an opening150through the end cap120a path is provided for the grout pipe to reach the bottom of the hole. The end cap120is also designed to increase turbulence in the bottom of the system thereby increasing the heat exchange with the formation below the system.

The heat exchanger110disclosed herein is a new form of engineered ground source heat exchanger, also referred to as a GeoExchange heat exchanger. In this configuration, it can be used to construct GeoExchange fields that are coupled with ground source heat pumps used in HVAC and hot water generating systems for residential, commercial and industrial applications. In addition and in configurations that require more robust materials, it can be used to extract heat from the Earth's crust at temperatures and pressures as required to generate electricity.

The heat exchanger110is configured to maximize the surface contact area of the heat exchanger with the formation at the borehole wall. It is also configured to maximize the separation distance and the insulation between the supply and return conduits (e.g., cavity126). It is configured to more efficiently utilize the lower portion of the borehole than typical heat exchangers. In addition it also minimizes parasitic losses due to the interaction between the supply and return conduits. The heat exchanger110also resists collapse due to formation and grout pressures at depths greater than are achievable using conventional heat exchangers.

When installing the heat exchanger110or a plurality of heat exchanger110into a system, the total drilling can be reduced by over ⅔ compared to when using a conventional vertical heat exchanger. This is illustrated in the above example. The heat exchanger110can also reduce the footprint of a field by when compared to the area required for a field constructed with conventional vertical heat exchangers. The heat exchanger110disclosed herein is a closed loop system that offers maximum efficiency compared to existing technologies with no significant adverse impact on the environment.

As disclosed herein the heat exchanger110is a vertical heat exchanger primarily for use with earth linked, more commonly referred to as geothermal or GeoExchange, HVAC systems. In one embodiment, the heat exchanger110is designed to be viable to depths up to 1500 feet and provide heat exchange for building loads up to 150,000 BTUh per borehole.

As discussed above the heat exchanger110is composed of two conduits, supply and return, formed so that when they are brought together their outer walls form what closely resembles the outer wall of a single pipe with the outer dimensions of a conventional pipe with a third conduit formed down the center.

The two conduits of the heat exchanger110are constructed as reinforced continuous conduits designed to carry fluids for the full length of the heat exchanger under pressure. The reinforcement simultaneously resists the external pressure exerted by the formation and grout preventing collapse of the conduits.

The third conduit formed down the center by bringing the two conduits together is dimensioned to allow the acceptance of a tremie (grouting) tube of sufficient size to allow pumping of enhanced grout through the tube to the bottom of the borehole with the heat exchanger in place.

The two conduits are joined at one end by an end cap that provides a closed loop path for the fluid from the supply (down) conduit to the return (up) conduit of the heat exchanger. As the grout is pumped down the tremie tube and the tremie tube is retracted from the borehole, the two conduits will spread apart providing maximum contact of their outer surfaces with the borehole wall and maximum separation from each other. As such and in some embodiments, the conduits will bow outward between the end cap and the transitions to further maximize contact of their outer surfaces with the borehole wall and maximum separation from each other.

The two conduits are connected to the distribution system with butt fuse fittings specifically designed as transitions from the shape of the individual conduits to standard HDPE pipe sizes, for example and in one non-limiting embodiment from the first conduit or supply conduit112to a supply conduit for example a 1½″ SDR11 HDPE.

The asymmetrical design of the two conduits provides maximum heat exchange between the heat exchanger and the formation as well as the utilization of the lower portions of the borehole.

The round fluid ports between the reinforcing bands in the conduits provide maximum efficiency for pressure drop at any given flow rate while maintaining sufficient flow turbulence for greatest heat exchange.

In one embodiment the heat exchanger110may be extruded with bimodal HDPE material such as HDPE100or similar ultrahigh density polyethylene resins. After extrusion, it may be rolled, banded or shrink wrapped for storage and/or shipping or stored and shipped on reels. If it is manufactured to specific lengths to match the borehole depth where it is intended to be installed, or if required by code, end caps may be factory installed by heat fusion. The transition fittings may be field installed by heat fusion.

In one embodiment, the heat exchanger110may be installed as follows, after a borehole is drilled and prepared, an appropriate length of the heat exchanger110may be pulled off the roll and straightened. A weighted anchor if desired is attached to the end cap120and a tremie tube is placed through the center hole of the end cap and the heat exchanger assembly110is pushed down the borehole, usually with mechanical assistance. The heat exchanger assembly110continues to be pulled off the roll and straightened while the tremie tube is threaded into the center of the assembly and pushed down the borehole until the bottom of the borehole is reached. The installer may fill the conduits with water to help offset the buoyancy created by the empty space in the conduits.

The borehole is then grouted per IGSHPA standards while the tremie tube is extracted and the heat exchanger is subsequently pressure tested. After pressure testing, the ends of the heat exchanger are sealed to prevent foreign material from entering the heat exchanger or it may be connected to the distribution system.

No mechanical connectors are used. All joints are heat fused per IGSHPA standards. No field joints are allowed in the borehole.

Although the heat exchanger110may be used in any earth coupled or lake loop heat exchange application with fluid operating temperatures between 25° F. and 125° F., one application is as a vertical heat exchanger for use with extended range ground source heat pump equipment. It is especially practical for areas where limited space prevents the use of conventional U-bend systems or where environmental concerns or maintenance issues prohibit the use of standing column well systems. It is an outstanding alternative in areas where drilling cost or installation labor cost render U-bend systems cost prohibitive because it requires only 30-35% of the total linear feet of active heat exchanger when compared to U-bend systems with comparable flow characteristics, can be installed in a borehole of comparable diameter, and can be installed, per foot, in a comparable time frame.

FIGS. 4-8are schematic illustrations of systems contemplated for use with the vertical heat exchanger of various embodiments of the present disclosure.

For example,FIGS. 4 and 5illustrate a GeoExchange system in a residential application.FIG. 4illustrates a forced air heating only system200. The forced air heating only system may be designed as a water-to-water forced air system using fan coil units (FCU) to supply heat to the conditioned space, or air handling units (AHU) to supply heat to the conditioned space.

FIG. 4illustrates the basic relationship between the GeoExchange System constructed with heat exchanger110or a plurality of heat exchanger110and any type of building system or process. Heat exchanger110is a closed loop system that exchanges heat between a geological feature and any other system or process adding or removing heat. A pump moves fluid from the GeoExchange System through a heat exchanger utilized by the Building or Process System200and returns the fluid to the GeoExchange system for recirculation.

FIG. 4illustrates a basic building system200that can be operably coupled to a plurality or at least one heat exchanger110. At least one pump202moves fluid from the heat exchanger110through a GSHP18utilized by the building system200. The building system200exchanges heat with the fluid and the fluid returns to the heat exchanger110. The fluid exchanges heat with the formation and is recirculated through the building system200by the pumping unit202in a closed loop. As used herein and below, “formation” refers to the earth the heat exchanger110is buried in.

FIG. 5illustrates how heat exchanger110may be used with building systems that operate in heating and cooling modes simultaneously. For example,FIG. 5illustrates a building system200that is equipped with multiple GSHP urns in a single system that can be operably coupled to a plurality or at least one heat exchanger110. At least one pump202moves fluid from the heat exchanger110system through equipment18utilized by the building system200. The building system200exchanges heat with the fluid and the fluid returns to the heat exchanger110. The fluid exchanges heat with the formation and is recirculated through the building system200by the pumping unit202. This system is a closed loop system.

FIG. 6illustrates how a multi-zone heat exchanger110system can be connected to a multi-zone building system running multiple processes simultaneously.FIG. 6illustrates a building system200with multiple zones and multiple and diverse applications of GSHP18that can be operably coupled to a plurality or at least one heat exchanger110. At least one pump202moves fluid from the heat exchanger110exchanger through the building system200. The building system200exchanges heat with the fluid and the fluid returns to the heat exchanger110. The fluid exchanges heat with the formation and is recirculated through the building system200by the pumping unit202. This system is a closed loop system.

FIGS. 7A and 7Billustrate how a heat exchanger110system may be utilized by a single purpose or dual purpose building system200, for instance heating only, cooling only, or heating and cooling.

InFIGS. 7A and 7Ba building system200is operated as a chilled water and heating hot water system that can be operably coupled to a plurality or at least one heat exchanger110. At least one pump202moves fluid from the heat exchanger110through a GSHP18utilized by the building system200. The building system200exchanges heat with the fluid and the fluid returns to the heat exchanger110. The fluid exchanges heat with the formation and is recirculated through the building system200by the pumping unit202. This system is a closed loop system.

FIG. 8illustrates how a heat exchanger110system can be isolated from a single purpose or multi-purpose building systems200to protect the purity of the fluid circulating in the heat exchanger110.

FIG. 8, illustrates a building system200operating as an industrial electricity generating facility coupled with secondary building systems200that can be operably coupled to a plurality or at least one heat exchanger110and maintain the purity of the fluid in the heat exchanger portion of the system by utilizing an isolating heat exchanger204. At least one pump202moves fluid from the heat exchanger110through the source side of the isolating heat exchanger204. Simultaneously, at least one pump202moves fluid from the building system200through the load side of the isolating heat exchanger204. The fluid from the heat exchanger110and the building system200exchange heat in the isolating heat exchanger204without coming into direct contact preserving the purity of the fluid circulating through the heat exchanger110. The fluid is recirculate through the heat exchanger110in a closed loop. Similarly, the fluid in the building system200is recirculated through the building system200.

InFIG. 8the area surrounded by the dashed lines250is alternative cascaded systems after electricity production.