Note: Descriptions are shown in the official language in which they were submitted.
CA 02526356 2005-11-14
GEOTHERMAL EXCHANGE SYSTEM USING A THERMALLY SUPERCONDUCTING
MEDIUM WITH A REFRIGERANT LOOP
TECHNICAL FIELD
The present invention relates generally to geothermal cooling systems,
and more particularly to a geothermal cooling device coupled with a
superconducting
heat transfer element for use as an air conditioner.
BACKGROUND OF THE INVENTION
Limitations of current art
Ground source heat pump systems, also known geothermal or
geoexchange systems, have been used for heating and cooling buildings for more
than
half a century. In 1993, the Environmental Protection Agency evaluated all
available
heating and cooling technologies and concluded that ground source heat pump
systems
were the most energy efficient systems available in the consumer marketplace.
Conventional ground source heat pump systems operate on a simple
principle. In the heating mode they collect heat energy from the ground and
transfer it
to a heat pump, which concentrates the heat and transfers it to a building's
heat
distribution system which in turn heats the building. In the cooling mode,
heat from the
building is collected by the cooling system and transferred to the heat pump,
which
concentrates the energy and transfers it to a ground source loop, which
transfers the
heat to the ground. In both modes, only a small amount of the heat comes from
the
electricity that runs the compressor; most of the heating and cooling energy
comes from
the ground. This allows ground source heat pump systems to achieve more than
100%
efficiency: every unit of electrical energy consumed by the heat pump produces
more
useable heat than an electrical resistance heater can produce with the same
unit of
electricity.
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Even though ground source heat pump systems achieve efficiencies of up
to 350% compared to less than 100% for many conventional systems, they have
been
slow to penetrate the consumer marketplace because of high capital costs, high
installation costs, difficult installation procedures and low energy cost
savings due to
historically low energy prices.
These high capital and installation costs have largely been due to
fundamental inefficiencies in the ground loop subsystem. In a typical
installation, the
ground loop consists of hundreds or thousands of feet of looped plastic piping
buried in
deep trenches or deep holes drilled into the ground. An antifreeze solution is
pumped
through this loop to absorb heat energy from the ground (in the heating mode)
or
transfer heat energy to the ground (in the cooling mode.) Few installations
have
sufficient available land for trenching so loops are most commonly installed
in deep
holes and this makes them relatively expensive for several reasons.
First, each loop consists of a supply and return line, which must fit down
the same hole. With an outer diameter of an inch or more for each pipe and a
tendency
for these pipes to bow away from each other due to the plastic material's
memory of
being coiled for shipment, the hole typically needs to have a diameter of 4 to
6 inches to
allow the loop to be installed. Holes of this size are relatively expensive to
drill and
require heavy equipment that disrupts landscaping, making it expensive to
retrofit
existing homes. Holes of this size also leave large voids around the loop that
must be
filled with materials such as bentonite clay in order for heat to transfer
from the ground
to the loop, which adds significantly to the cost of installation.
Second, having both supply and return lines in the same hole results in
thermal "short circuiting" which reduces the efficiency of the loop. In the
heating mode,
for example, cool fluid from the heat pump absorbs heat from the ground as it
goes
down the supply line in the hole, cooling the ground around the pipe. When the
warmed
fluid comes back up the hole in the return line, it passes through the ground
that was
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just cooled, losing some of the heat it has just picked up. This lowers the
efficiency of
the loop so the loop must be made longer to compensate, adding to the cost of
drilling
and piping.
Third, for the ground loop to function, the antifreeze solution must be
pumped through hundreds or thousands of feet of small diameter piping. This
consumes
a significant amount of electric energy, lowering the overall efficiency of
the system.
In recent years, a new ground source heat pump technology has evolved
to overcome some of the inefficiencies of conventional systems. This
technology,
called "direct geoexchange," replaces the conventional plastic ground loop
with a small-
diameter copper loop. Instead of an antifreeze solution, direct geoexchange
systems
pump a refrigerant through the loop to pick up heat from the ground or give
off heat to
the ground in the same way that conventional ground loops function.
Direct geoexchange has some significant advantages over conventional
systems. First, the direct geoexchange loop runs directly to and from the heat
pump's
compressor, eliminating the heat exchanger that is required by conventional
systems to
transfer heat from the loop to the heat pump. Second, the small diameter of
the direct
exchange loop makes it possible for loops to be installed in smaller diameter
holes in
the ground; this reduces the cost of drilling and backfilling the holes and
reduces the
size of the drill rig required to drill the holes, decreasing damage to
landscaping in
retrofit applications. Third, the copper pipes used in direct geoexchange
transfer heat
more efficiently to and from the ground so the total length of loop required
is typically
less than conventional systems. Because of these improvements, direct
geoexchange
systems can be cheaper than conventional ground source systems and more energy
efficient.
In spite of these inherent advantages, direct geoexchange also has some
significant disadvantages. First, both supply and return pipes run in the same
hole, so
the thermal short circuit problems of conventional systems remain. Second, the
loop
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system pumps much more refrigerant through many more feet of piping past many
more
connections than conventional systems, so the potential for refrigerant leaks
is
increased. Third, direct geoexchange requires large volumes of refrigerant to
flow
through the loop, behaving differently in the heating and cooling modes, and
requiring
additional refrigerant reservoirs and flow control systems to compensate.
Because of
these inefficiencies, direct geoexchange is only able to achieve a modest
improvement
in total energy efficiency over conventional ground source heat pump systems.
Direct geoexchange and conventional ground source heat pump systems
have additional limitations. Both require a significant amount of electrical
power to
pump fluids through hundreds or thousands of feet of piping. This not only
limits overall
system efficiency but also limits the environments in which it can be
installed. This kind
of power is not often available or reliable in the world's developing
countries, so existing
ground source heat pump systems have limited potential to penetrate broad
world
markets. In addition, since both systems are designed to heat and cool whole
buildings,
neither can efficiently be installed on the incremental room-by-room basis on
which
most of the world adopts heating and air conditioning.
In summary, conventional geoexchange systems and direct expansion
geoexchange systems have significant limitations in energy efficiency,
installation cost
and installation flexibility.
There is a need for a geothermal exchange system that operates in
combination with a refrigerant heat intensification loop, utilizes less power
than
conventional refrigerant or coolant based geoexchange systems, results in
lightweight
heat exchangers that can be configured in a wide range of interior locations,
has an
extended lifetime due to fewer parts, has reduced ground loop installation
costs and
provides enhanced cooling and heating efficiency compared to power used.
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SUMMARY OF THE INVENTION
According to one aspect of the present invention, there is provided a
geothermal exchange system using a refrigerant loop with high heat transfer
superconductor couplable to an earth source. The system includes a compressor,
a first
heat exchanger and a second heat exchanger, each of the heat exchangers
adapted to
function interchangeably as an evaporator and a condenser, such that the first
heat
exchanger is operable as an evaporator and the second heat exchanger is
operable as
a condenser when the system is operating in cooling mode, and such that the
first heat
exchanger is operable as a condenser and the second heat exchanger is operable
as
an evaporator when the system is operating in heating mode, at least one first
conduit in
communication with the compressor and each of the heat exchangers and adapted
for
carrying refrigerant through the system to each of the heat exchangers, the at
least one
conduit including a return conduit for carrying refrigerant gas back to the
compressor, a
reversing valve in communication with said at least one conduit and configured
to
reverse the flow of refrigerant from the compressor to the heat exchangers
depending
upon whether the system is operating in the cooling mode or the heating mode;
and an
above ground thermal superconductor segment thermally coupled to the second
heat
exchanger. When the system is operating in heating mode, the valve is
activated to
direct refrigerant pumped from the compressor through the at least one conduit
to the
first heat exchanger where the refrigerant gas is condensed into liquid,
through the
return conduit to the second heat exchanger where the liquid is vaporized into
gas and
heat is efficiently transferred from earth source through the thermal
superconductor, and
back to the compressor via the return conduit; and such that when the system
is
operating in cooling mode, the valve is activated to direct refrigerant pumped
from the
compressor through the at least one conduit to the second heat exchanger where
the
refrigerant gas is condensed into liquid and heat is efficiently transferred
to earth source
through the thermal superconductor, through the return conduit to the first
heat
exchanger wherein the liquid is vaporized into gas, and back to the compressor
via the
return conduit.
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According to another aspect of the present invention, there is provided a
cooling device using an efficient geothermal system with a high heat transfer
superconductor couplable to an earth source. The cooling device includes a
compressor, a first heat exchanger and a second heat exchanger, such that the
first
heat exchanger is operable as an evaporator and the second heat exchanger is
operable as a condenser in a cooling mode, at least one first conduit in
communication
with the compressor and first heat exchanger and adapted for carrying
refrigerant
through the system to each of the heat exchangers, the at least one conduit
including a
return conduit for carrying refrigerant gas back to the compressor from the
second heat
exchanger, an above ground thermal superconductor segment thermally coupled to
the
second heat exchanger, and such that refrigerant is pumped from the compressor
through the at least one conduit to the second heat exchanger where the
refrigerant gas
is condensed into liquid and heat is efficiently transferred to earth source
through the
thermal superconductor, the refrigerant transfers through the return conduit
to the first
heat exchanger wherein the liquid is vaporized into gas, and back to the
compressor via
the return conduit.
According to another aspect of the present invention, there is provided a
heating device using an efficient geothermal system with high heat transfer
superconductor couplable to an earth source. The heating device includes, a
compressor, a first heat exchanger and a second heat exchanger, such that the
first
heat exchanger is operable as an evaporator and the second heat exchanger is
operable as a condenser in a cooling mode at least one first conduit in
communication
with the compressor and first heat exchanger and adapted for carrying
refrigerant
through the system to each of the heat exchangers, the at least one conduit
including a
return conduit for carrying refrigerant gas back to the compressor from the
second heat
exchanger, an above ground thermal superconductor segment thermally coupled to
the
second heat exchanger, such that refrigerant is pumped from the compressor
through
the at least one conduit to the second heat exchanger where the refrigerant
gas is
condensed into liquid and heat is efficiently transferred to earth source
through the
thermal superconductor, the refrigerant transfers through the return conduit
to the first
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heat exchanger wherein the liquid is vaporized into gas, and back to the
compressor via
the return conduit.
According to another aspect of the present invention, there is provided a
geothermal exchange system using a refrigerant loop with an interconnect
couplable to
a high heat transfer superconductor couplable to an earth source. The
geothermal
exchange system includes, a compressor, a first heat exchanger and a second
heat
exchanger, each of the heat exchangers adapted to function interchangeably as
an
evaporator and a condenser, wherein the first heat exchanger is operable as an
evaporator and the second heat exchanger is operable as a condenser when the
system is operating in cooling mode, and wherein the first heat exchanger is
operable
as a condenser and the second heat exchanger is operable as an evaporator when
the
system is operating in heating mode, at least one first conduit in
communication with the
compressor and each of the heat exchangers and adapted for carrying
refrigerant
through the system to each of the heat exchangers, the at least one conduit
including a
return conduit for carrying refrigerant gas back to the compressor, a
reversing valve in
communication with the at least one conduit and configured to reverse the flow
of
refrigerant from the compressor to the heat exchangers depending upon whether
the
system is operating in the cooling mode or the heating mode; and a thermal
interconnect thermally coupled to the second heat exchanger, and thermally
couplable
to thermal superconductor segment such that heat transfer losses are less than
20%,
such that when the system is operating in heating mode, the valve is activated
to direct
refrigerant pumped from the compressor through the at least one conduit to the
first
heat exchanger where the refrigerant gas is condensed into liquid, through the
return
conduit to the second heat exchanger where the liquid is vaporized into gas
and heat is
efficiently transferred from earth source through the thermal interconnect to
the thermal
superconductor, and back to the compressor via the return conduit, and such
that when
the system is operating in cooling mode, the valve is activated to direct
refrigerant
pumped from the compressor through the at least one conduit to the second heat
exchanger where the refrigerant gas is condensed into liquid and heat is
efficiently
transferred to earth source through the thermal superconductor, through the
return
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conduit to the first heat exchanger wherein the liquid is vaporized into gas,
and back to
the compressor via the return conduit.
According to another aspect of the present invention, there is provided a
cooling device using an efficient geothermal system with interconnect
couplable to high
heat transfer superconductor couplable to an earth source. The cooling device
includes
a compressor, a first heat exchanger and a second heat exchanger, such that
the first
heat exchanger is operable as an evaporator and the second heat exchanger is
operable as a condenser in a cooling mode, at least one first conduit in
communication
with the compressor and first heat exchanger and adapted for carrying
refrigerant
through the system to each of the heat exchangers, the at least one conduit
including a
return conduit for carrying refrigerant gas back to the compressor from the
second heat
exchanger, a thermal interconnect thermally coupled to the second heat
exchanger, and
thermally couplable to thermal superconductor segment such that heat transfer
losses
are less than 20%, and such that refrigerant is pumped from the compressor
through
the at least one conduit to the second heat exchanger where the refrigerant
gas is
condensed into liquid and heat is efficiently transferred to earth source
through the
thermal interconnect and the thermal superconductor, the refrigerant transfers
through
the return conduit to the first heat exchanger wherein the liquid is vaporized
into gas,
and back to the compressor via the return conduit.
According to another aspect of the present invention, there is provided a
heating device using an efficient geothermal system with interconnect
couplable to high
heat transfer superconductor couplable to an earth source. The heating device
includes
a compressor, a first heat exchanger and a second heat exchanger, such that
the first
heat exchanger is operable as an evaporator and the second heat exchanger is
operable as a condenser in a cooling mode, at least one first conduit in
communication
with the compressor and first heat exchanger and adapted for carrying
refrigerant
through the system to each of the heat exchangers, the at least one conduit
including a
return conduit for carrying refrigerant gas back to the compressor from the
second heat
exchanger, a thermal interconnect thermally coupled to the second heat
exchanger, and
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thermally couplable to thermal superconductor segment such that heat transfer
losses
are less than 20%, and such that refrigerant is pumped from the compressor
through
the at least one conduit to the second heat exchanger where the refrigerant
gas is
condensed into liquid and heat is efficiently transferred to earth source
through the
thermal interconnect and the thermal superconductor, the refrigerant transfers
through
the return conduit to the first heat exchanger, such that the liquid is
vaporized into gas,
efficiently absorbing heat from the heat exchanger and transferred back to the
compressor via the return conduit.
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BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE 1: A THERMALLY SUPERCONDUCTING GEOTHERMAL
EXCHANGE SYSTEM FOR HEATING AND COOLING: This figure illustrates a
schematic of an efficient geothermal exchange system with thermal
superconductor
transfer from a ground source to a reversing refrigerant based heat pump.
FIGURE 2: A THERMALLY SUPERCONDUCTING GEOTHERMAL
EXCHANGE SYSTEM FOR HEATING AND COOLING WITH MULTIPLE GROUND
SOURCE COMPONENTS: This figure illustrates a schematic of an efficient
geothermal
exchange system with a plurality of ground source components.
FIGURE 3: A THERMALLY SUPERCONDUCTING GEOTHERMAL
EXCHANGE SYSTEM FOR HEATING AND COOLING AIR: This figure shows a
schematic of an efficient geothermal exchange system with thermal
superconductor
transfer from a ground source to a reversing refrigerant based heat pump
configured for
air heat exchange.
FIGURE 4: A THERMALLY SUPERCONDUCTING GEOTHERMAL
EXCHANGE SYSTEM FOR DIRECT HEATING AND COOLING LIQUID: This figure
shows a schematic of an efficient geothermal exchange system with thermal
superconductor transfer from a ground source to a reversing refrigerant based
heat
pump configured for direct thermal exchange to a circulating fluid in a tank.
FIGURE 5: A THERMALLY SUPERCONDUCTING GEOTHERMAL
EXCHANGE SYSTEM FOR INDIRECT HEATING AND COOLING OF A LIQUID: This
figure shows a schematic of an efficient geothermal exchange system with
thermal
superconductor transfer from a ground source to a reversing refrigerant based
heat
pump configured for indirect thermal exchange to a circulating fluid by way of
an
intermediating fluid in a tank.
CA 02526356 2005-11-14
FIGURE 6: A THERMALLY SUPERCONDUCTING GEOTHERMAL
EXCHANGE SYSTEM FOR HEATING AND COOLING LIQUID: This figure shows a
schematic of an efficient geothermal exchange system with thermal
superconductor
transfer from a ground source to a reversing refrigerant based heat pump
configured for
direct thermal exchange to a fluid loop.
FIGURE 7: A THERMALLY SUPERCONDUCTING GEOTHERMAL
EXCHANGE SYSTEM WITH SPLIT HOUSING FOR HEATING AND COOLING AIR:
This figure shows a schematic of an efficient geothermal exchange system
showing
separate housings for groups of system components. Figure 7a shows air
exchange
components housed separately from other components; figure 7b illustrates an
enclosure for air exchange components.
FIGURE 8: A THERMALLY SUPERCONDUCTING GEOTHERMAL
EXCHANGE SYSTEM FOR HEATING AND COOLING AIR, WITH MULTIPLE SPLIT
HOUSINGS: This figure shows a schematic of an efficient geothermal exchange
system
showing separate housings for groups of system components, with air exchange
components, ground source heat exchanger components and remaining above-ground
components housed in separate enclosures.
FIGURE 9: A THERMALLY SUPERCONDUCTING GEOTHERMAL
EXCHANGE SYSTEM IN HEATING ONLY MODE: This figure shows a schematic of an
efficient geothermal exchange system with thermal superconductor transfer from
a
ground source to a reversing refrigerant based heat pump.
FIGURE 10: A THERMALLY SUPERCONDUCTING GEOTHERMAL
EXCHANGE SYSTEM IN HEATING ONLY MODE WITH AIR HEAT EXCHANGER:
This figure shows a schematic of an efficient geothermal exchange system with
thermal
superconductor transfer from a ground source to a reversing refrigerant based
heat
pump configured for air heat exchange.
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FIGURE 11: A THERMALLY SUPERCONDUCTING GEOTHERMAL
EXCHANGE SYSTEM FOR DIRECT HEATING LIQUID: This figure shows a schematic
of an efficient geothermal exchange system with thermal superconductor
transfer from a
ground source to a reversing refrigerant based heat pump configured for direct
thermal
exchange to a circulating fluid in a tank.
FIGURE 12: A THERMALLY SUPERCONDUCTING GEOTHERMAL
EXCHANGE SYSTEM FOR INDIRECT HEATING A LIQUID: This figure shows a
schematic of an efficient geothermal exchange system with thermal
superconductor
transfer from a ground source to a reversing refrigerant based heat pump
configured for
indirect thermal exchange to a circulating fluid by way of an intermediating
fluid in a
tank.
FIGURE 13: A THERMALLY SUPERCONDUCTING GEOTHERMAL
EXCHANGE SYSTEM FOR HEATING LIQUID: This figure shows a schematic of an
efficient geothermal exchange system with thermal superconductor transfer from
a
ground source to a reversing refrigerant based heat pump configured for direct
thermal
exchange to a fluid loop.
FIGURE 14: A THERMALLY SUPERCONDUCTING GEOTHERMAL
EXCHANGE SYSTEM WITH SPLIT HOUSING FOR HEATING AIR: This figure shows
a schematic of an efficient geothermal exchange system showing separate
housings for
groups of system components. Figure 14a shows air exchange components housed
separately from other components; figure 14b illustrates an enclosure for air
exchange
components.
FIGURE 15: A THERMALLY SUPERCONDUCTING GEOTHERMAL
EXCHANGE SYSTEM FOR HEATING AIR, WITH MULTIPLE SPLIT HOUSINGS: This
figure shows a schematic of an efficient geothermal exchange system showing
separate
housings for groups of system components, with air exchange components, ground
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source heat exchanger components and remaining above-ground components housed
in separate enclosures.
FIGURE 16: A THERMALLY SUPERCONDUCTING GEOTHERMAL
EXCHANGE SYSTEM FOR COOLING ONLY: This figure shows a schematic of an
efficient geothermal exchange system with thermal superconductor transfer from
a
ground source to a reversing refrigerant based heat pump.
FIGURE 17: A THERMALLY SUPERCONDUCTING GEOTHERMAL
EXCHANGE SYSTEM FOR COOLING ONLY WITH AIR HEAT EXCHANGER: This
figure shows a schematic of an efficient geothermal exchange system with
thermal
superconductor transfer from a ground source to a reversing refrigerant based
heat
pump configured for air heat exchange.
FIGURE 18 A THERMALLY SUPERCONDUCTING GEOTHERMAL
EXCHANGE SYSTEM WITH SPLIT HOUSING FOR COOLING AIR: This figure shows
a schematic of an efficient geothermal exchange system showing separate
housings for
groups of system components. Figure 18a shows air exchange components housed
separately from other components; figure 18b illustrates an enclosure for air
exchange
components.
FIGURE 19: A THERMALLY SUPERCONDUCTING GEOTHERMAL
EXCHANGE SYSTEM FOR COOLING AIR, WITH MULTIPLE SPLIT HOUSINGS: This
figure shows a schematic of an efficient geothermal exchange system showing
separate
housings for groups of system components, with air exchange components, ground
source heat exchanger components and remaining above-ground components housed
in separate enclosures.
FIGURE 20: A THERMALLY SUPERCONDUCTING GEOTHERMAL
EXCHANGE SYSTEM COUPLABLE TO A SUPERCONDUCTION GEOEXCHANGE
GROUND LOOP: Figure 20a shows a schematic of an efficient geothermal exchange
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system couplable to a superconducting geoexchange grounde loop. Figure 20b
shows
the ground source heat exchange component of the system in Fig 20a configured
to
receive the end of a superconducting ground source element, with direct metal-
to-metal
thermal conduction. Figure 20c shows the ground source heat exchange component
configured for indirect coupling with a superconducting ground source element
through
an intermediating thermal paste.
FIGURE 21: GROUND SOURCE HEAT EXCHANGER FOR COUPLING
WITH A THERMALLY SUPERCONDUCTING GROUND SOURCE ELEMENT: Figure
21 a shows a heat exchanger with a refrigerant coil wound around a metal
sleeve which
is configured to receive the end of a superconducting ground source component.
Figure
21 b sows a heat exchanger with a refrigerant vessel surrounding a metal
sleeve which
is configured to receive the end of a superconducting ground source component.
FIGURE 22: A THERMALLY SUPERCONDUCTING GEOTHERMAL
EXCHANGE HEATING SYSTEM COUPLABLE TO A SUPECONDUCTING GROUND
LOOP: This figure shows a schematic of an efficient geothermal exchange
heating
system with a ground source heat exchange component configured to receive a
superconducting ground loop component.
FIGURE 23: A THERMALLY SUPERCONDUCTING GEOTHERMAL
EXCHANGE COOLING SYSTEM COUPLABLE TO A SUPECONDUCTING GROUND
LOOP: This figure shows a schematic of an efficient geothermal exchange
cooling
system with a ground source heat exchange component configured to receive a
superconducting ground loop component.
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DETAILED DESCRIPTION OF THE INVENTION
With reference to the drawings, new and improved heating and cooling
devices and geothermal exchange systems embodying the principles and concepts
of
the present invention will be described. In particular, the devices and
systems are
applicable for climate control within structures as well as more generally to
bi-directional
heat transfer to and from earth sources. The embodiments shown in the attached
figures satisfy the need for a geothermal exchange system with improved
thermal
efficiency, lower installation cost and greater installation flexibility.
Recent advances in thermal superconducting materials can now be
considered for use in novel energy transfer applications. For example, US
patent
6132823 and continuations thereof, disclose an example of a heat transfer
medium with
extremely high thermal conductivity, and is included herein by reference.
Specifically the
following disclosure indicates the orders of magnitude improvement in thermal
conduction; "Experimentation has shown that a steel conduit 4 with medium 6
properly
disposed therein has a thermal conductivity that is generally 20,000 times
higher than
the thermal conductivity of silver, and can reach under laboratory conditions
a thermal
conductivity that is 30,000 times higher that the thermal conductivity of
silver." Such a
medium is thermally superconducting. Throughout the disclosure, the term
superconductor shall interchangeably mean thermal superconductor or thermal
superconductor heat pipe. The available product sold by Qu Energy
International
Corporation is an inorganic heat transfer medium provided in a vacuum-sealed
heat
conducting tube.
Alternate thermal superconductors may be equivalently substituted, such
as thermally superconducting heat pipes. Heat pipes typically include a sealed
container
(pipe), working fluid and a wicking or capillary structure inside the
container. Heat is
transported by an evaporation-condensation cycle when a thermal differential
is present
between opposing ends. Working fluids can be selected with high surface
tension to
generate a high capillary driving force such that the condensate can migrate
back to the
evaporator portion, even against gravity. Some working fluids useful for the
geothermal
CA 02526356 2005-11-14
operating temperature range include ammonia, acetone, methanol and ethanol.
Inside
the tube, the liquid enters and wets the internal surfaces of the capillary
structure.
Applying heat at one segment of the pipe causes the liquid at that point to
vaporize
picking up latent heat of vaporization. The gas moves to a colder location
where it
condenses, giving up latent heat of vaporization. The heat transfer capacity
of a heat
pipe is proportional to the axial power rating, the energy moving axially
along the pipe.
For maximum energy transfer the heat pipe diameter must be increased and the
length
shortened, making it operable but less preferred than a non-liquid
superconductor such
as the Qu product. In particular with respect to the ground loop, scaled up
heat pipe
designs have been disclosed for geothermal heating applications such as for
PCT
publication WO 86/00124, "Improvements in earth heat recovery systems", these
designs partially overcome the length to diameter ratio problem but preferably
require a
recirculation pump for the fluid. A two-way heat pipe design for ventilation
heat
exchanger is disclosed in US patent 4896716, and could be used for non-ground
loop
transfer as a two-way thermal superconductor.
Fig. 1 illustrates an embodiment of the invention in which heat is
transferred bi-directionally using a thermal superconducting medium, such as
described
above. Generally, heat is transferred to and from a thermal superconductor
earth source
loop by a thermal superconductor heat exchange coil configured through a
refrigerant
loop subsystem with direction of heat flow controlled by a standard reversing
valve
system. Specifically, superconductor geothermal exchange active components are
positioned above ground level 46 and couplable to a geothermal ground loop 48
formed
from thermal superconductor and positioned in a ground loop hole 50. The
ground loop
refrigerant or coolant circulating loops of conventional geoexchange systems
are
replaced with thermally superconducting transfer coils that are operable bi-
directionally,
resulting in many advantages of efficiency, reduced size, and fewer
components. The
ground loop thermal superconductor extends above ground level where it is
covered by
insulation 25 and terminated in a coupler 44. For illustrative purposes, this
superconductor may be in the form of a sealed metal tube as currently
available from
Qu Corporation and will be preferred to be in tube form. Alternatively other
available
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thermal superconductors could be similarly substituted that may have various
forms and
cross sections such as flexible conduits, thin laminate, thin film coated
metal etc, that
may be suitable depending on the site and system conditions.
In the preferred case, the depth of hole D is selected in combination with
the thermal transfer properties of the thermal superconductor element, the
thermal
transfer properties of the ground around hole D and the maximum expected rate
of heat
transfer between the heating/cooling system and the ground, in order to
provide a
desired heating and cooling capacity for the system. As in conventional
geoexchange
systems, the depth of hole 34 may be greater than is practicable for a single
hole, so a
plurality of holes may be substituted to receive a plurality of geothermal
heat exchange
elements with an aggregate depth equal to or greater than the required depth
of a single
hole. As shown in Figure 2, this plurality of geothermal heat exchange units
can be
joined at or below coupler 28 in such a manner that they are equally able to
transfer
heat to the ground. Due to the improved thermal transfer properties of the
superconductor, the hole size and depth can be considerably less than
conventional
geoexchange loops, saving installation costs and increasing the number of
potential
sites that can install geothermal exchange. As is known to those skilled in
the art of
conventional geothermal installations, hole 50 may equivalently be a trench in
the
ground 46, or alternatively the ground 46 may equivalently be a body of water
such as a
pond, well, river, sea or the like and the meaning of ground used herein shall
include
body of water. The coupler 44 couples between the ground loop superconductor
48
and a ground link superconductor segment 40 that transfers heat to and from a
heat
intensifier system, providing for ease of installation and conduit routing
prior to
connection. Optionally, the coupler may be eliminated in a direct installation
design.
The superconductor segment 40 extends to be in thermal contact with a
heat exchange segment 68 of a refrigerant loop that functions to circulate
heat
transferred to and from the ground loop. The refrigerant loop circuit forms a
refrigerant
transfer path which includes a compressor 20 having outlet connected to
refrigerant
conduit 22 to a reversing valve 28 to a space heat exchanger 38 to a conduit
32
17
CA 02526356 2005-11-14
connected to a directional expander 62 with conduit 64 to a ground heat
exchanger 28
connected to a return conduit 34, through the reversing valve 28 and an
optional
accumulator 23 to a return conduit 24 to the inlet of the compressor 20. As
will be
obvious to one skilled in the art of reversible heat pumps, the space heat
exchanger or
ground heat exchanger are interoperable as condenser or evaporator heat
exchangers
to provide heating or cooling modes as the reversing valve 28 is switched from
a first
position to a second position.
When the refrigerant loop as described is filled with a suitable amount of
refrigerant, the refrigerant heat exchange circuit is operated by turning the
compressor
on. In a heating mode example of the flow of refrigerant, the compressor 20
compresses a gaseous refrigerant to intensify its heat content, circulates it
through
conduit 22 to the space heat exchanger 38 which acts as a condenser causing
the
gaseous refrigerant to condense to a liquid (or partial liquid) before passing
through
conduit 60 to expander 62 which rapidly expands the liquid in a pressure drop
to change
the refrigerant state to cooled vapor which absorbs heat at the evaporator
heat
exchanger 68 from the ground loop before passing through return conduit 34 to
optional
accumulator 23 (where any remaining liquid is trapped and vaporized) after
which the
remaining refrigerant transfers through conduit 24 to complete the loop at the
compressor inlet. This creates a temperature differential between space heat
exchanger
38 and ground heat exchanger 68. In the preferred case, the refrigerant heat
exchangers are isolated by insulation 25 as shown. The reversing valve 28
functions to
direct the refrigerant flow in alternate directions, which reverses the
thermal function of
the heat exchangers becoming condenser and evaporator in open mode and
evaporator
and condenser in closed mode respectively. A thermal sensor 18 is associated
with the
medium to be conditioned by space heat exchange coil 38. A controller 16 is
powered
by power line 14 and provides power to compressor 20 and reversing valve 28,
as well
as control data to and from thermal sensor 26. Space heat exchange coil 38 can
be
configured in any geometric arrangement related to a structure to optimize
heat transfer
to a specific medium. Insulation 25 also preferably covers superconductor
transfer
18
CA 02526356 2005-11-14
segments outside of coupling connections and heat exchange sections, to reduce
thermal transfer losses.
The superconductor geothermal exchange system 110 is operated in
either a heating or cooling mode depending on the difference between the
actual
measured temperature and a desired set-point programmed in the thermostatic
controller 16. For example, when the desired temperature is higher than actual
temperature the superconductor geothermal exchange system 110 is operated in a
heating mode. In heating mode, reversing valve 28 is opened such that space
heat
exchanger 38 operates as a condenser giving off heat and ground heat exchanger
68
operates as an evaporator receiving heat from ground link superconductor 40,
while
controller 16 operates compressor 20. Heat is then efficiently transferred
from ground
loop 48 to the ground heat exchanger 68, then efficiently transferred through
the
refrigerating loop to space heat exchanger for related heating use. In the
cooling mode
example, when the desired temperature is lower than actual temperature, the
superconductor geothermal exchange system 110 is operated in a cooling mode.
In
cooling mode, reversing valve 28 is closed such that space heat exchanger 38
operates
as an evaporator receiving heat and ground heat exchanger 68 operates as a
condenser giving off heat to ground link superconductor 40, while controller
16 operates
compressor 20. Heat is then efficiently transferred from space heat exchanger
68 to
ground loop 48 for related cooling use. The modes may simply switch on/off
rather than
oscillate between heating and cooling based on controller programming and
averaging
forecasting.
The refrigerant loop circuit may have additional components as required to
scale for larger energy applications. As known in the art of conventional heat
pump
systems, such larger systems may have receivers, suction accumulators, bulb
sensors,
thermostatic expansion metering valves and the like to manage refrigerant flow
through
the circuit.
19
CA 02526356 2005-11-14
The superconductor geothermal exchange system 110 attached to
segment 40 above coupler 44 can be enclosed a number of ways, depending on
application. For example all components shown could be housed inside one
enclosure
12.
As obvious to one skilled in the art, the coupler 44 could equivalently be
alternatively positioned under the ground, above ground outside a structure,
inside a
structure but outside the housing 12, or even inside the housing 12, as
selected for best
ease of installation. Housing 12 may include ambient vents for convective
cooling of the
compressor. A further embodiment of the superconductor geothermal exchange
system
110 can eliminate the coupler 44 by configuring the switch to have a ground
loop
receptacle to accept the termination of the superconductor ground loop 48 such
that the
ground loop 48 can be separately installed from the rest of the system.
By changing the ground loop from a conventional fluid loop to a
superconductor element, geoexchange system 110 eliminates the energy required
to
circulate ground loop fluids and as a result uses less power to operate,
making it
possible for new improved components to be utilized. For example, a low power
compressor can be used, such as is available from Danfoss Corporation. In one
embodiment the low power compressor 20 can have power less than 4500W. In an
alternate embodiment the low power compressor 20 requires power less than
1800W,
making it suitable for common North American household outlets, resulting in
more
convenient installation that conventional systems requiring higher power.
The superconductor geothermal exchange system 110 may operate from
conventional AC grid power, or, alternatively, from a DC power source such as
a
hydrogen fuel cell, a solar cell array, or a wind turbine or the like. In
either AC or DC
power embodiments, individual components may be AC or DC powered, with power
conditioners provided as required (not shown), being delivered to the system
110
already conditioned externally or delivered requiring additional conditioning,
as will be
obvious to one skilled in the art. In the DC powered embodiment in which all
CA 02526356 2005-11-14
components operate on a single voltage of DC power, low voltage alternative
energy
power may be used directly, without power conditioning, thereby reducing
energy loss
and potentially eliminating the need for power conditioning devices.
Using the preferred thermal superconducting tubes, it is preferred to have
insulation along the length of all superconductor segments except heat
exchanger coil
segments or thermal transfer couplings to other components, to limit heat loss
and
condensation buildup. However alternate thermal superconductor embodiments may
have integrated insulating layers or have acceptable transfer loss such that
the
superconductor geothermal exchange system 110 is operable.
Figure 2 illustrates an embodiment of system 110 of Figure 1 in which the
required depth of hole 34 is greater than is practicable for a single hole. In
this
embodiment, the single geothermal heat exchange element is replaced with a
plurality
of such elements in a plurality of holes with an aggregate depth equal to or
greater than
the required depth of a single hole. This plurality of geothermal heat
exchange units
can be joined at or below coupler 28 in such a manner that they are equally
able to
transfer heat to the ground.
The superconductor geothermal exchange system 110 of Figures 1 can
be configured for air heating and cooling as shown in Figure 3. Superconductor
geothermal exchange system 120 is designed for air heating and cooling inside
a
structure, with the following modifications and additions. Enclosure 12 has
two vented
regions to provide an inlet and outlet for circulated air. Between the two
vented regions
is the space heat exchanger coil 38, which is further insulated by insulation
25 up to the
coil. A blower 54 is positioned in proximity to the space heat exchanger 38 to
pull or
push air through the exchanger for heating or cooling, the preferred position
being near
the outlet vent region such that air is pulled over the space heat exchanger
38. The fan
can be a low power, low throughput fan to conserve energy, or alternatively a
variable
speed fan. The preferred fan has operating noise less than 45 dB and can be DC
21
CA 02526356 2005-11-14
powered by an alternative energy source (not shown). Space heat exchanger 38
may
be configured in many possible designs provided sufficient net surface area is
exposed
to the air flow; the illustration of an array of bars substantially
corresponding to the fan
diameter is a preferred example. Alternatively, as is well known in the art of
air heat
exchangers, metal fins could be added to increase the surface area of the heat
exchanger. Blower 54 is connected to controller 16 and power line 14 for
control of fan
operation. In the cooling mode, under some ambient conditions, condensate will
form
on the space heat exchanger 38, and an optional drip tray 56 is shown
positioned below
to catch condensate and an optional water drain line 58 is shown connected to
drip tray
for runoff disposal.
The controlled operation of the superconductor geothermal exchange
system 120 is essential for user comfort and control of heating and cooling.
Controller
16 may be programmed as a thermostat controller responding to a temperature
sensor
26 (such as a thermocouple) associated with the space to be heated or cooled,
or as a
controller that receives input from a remote thermostat and sensor associated
with the
space (not shown). The controller is shown within the housing 12, but may
alternatively
be in any location provided it is in communication with the blower and
temperature
sensor. While the simplest implementation is one temperature measurement, to
one
skilled in the art, multiple temperature measurements could be weighted or
averaged for
the purpose of feedback set points in the controller 16. In the case of a
multi-speed fan,
alternatively a second temperature sensor could be positioned on or near the
space
heat exchanger 38 to determine the initial fan speed for faster cooling.
Unlike
conventional central geothermal heat pumps, which are large, noisy and require
greater
power than available from a standard household outlet, the air exchange
subsystem in
enclosure 60 can be operated from a standard power outlet, anywhere in the
house,
quietly and in a small form factor housing. The housing 60 for air exchange
subsystem,
may be positioned anywhere within the interior room to be cooled or heated,
and does
not have to be near an exterior wall or window. Preferably the housing is
positioned to
provide optimum air mixing and heating for the room.
22
CA 02526356 2005-11-14
Operating modes are similar to those described for figure 1, with the
additional mode of operating the blower in combination with operating the
intensifying
compressor for improving the rate of heat exchange with the air space to be
conditioned. With the controller 16 set to a desired room temperature T1, via
a manual
input (not shown), or a remote control input, or a second remote thermostat
(not shown)
in communication with the controller 16, the controller senses existing room
temperature
T2 and if higher or lower than T1, switches reversing valve 28 to create
appropriate
heating or cooling circuit, operates the compressor 20 to circulate heated
refrigerant
and operates blower 54 to circulate air until the temperature reaches T1.
Alternatively,
as common in the art, various thresholding or smoothing processes can be
programmed
to avoid jitter and determine when to switch the blower 54 on or off. In the
example of a
multi-speed blower, the blower speed can be programmed to change in response
to the
rate of change of existing temperature T2, in addition to on or off. The
superconductor
geothermal exchange system 120 can be programmed to operate for any input that
acts
as a related proxy for associated interior temperature and has a known
characterized
relationship to temperature.
A further embodiment of the superconductor geothermal exchange system
120 can eliminate the coupler 44 by configuring the switch to have a ground
loop
receptacle portion to accept the termination of the superconductor ground loop
48, such
that the ground loop 48 can be separately installed from the rest of the
system. It will be
obvious to one skilled in the art that there are many equivalent designs to
couple the
ground loop superconductor to the switch including intermediate coupler
segments.
The superconductor geothermal exchange systems of Figures 1 and 2
have many advantages that solve the problems described in the background, due
to the
substantial efficiency increase relative to existing geoexchange solutions.
These
efficiency gains result in coefficient of performance of greater than 2 and
potentially as
high as 5 or more (relative to the efficiency of an electric resistance wire
which is
generally understood to have a coefficient of performance of 1), beyond the
limits of
conventional geoexchange. First, the hole depth of the geothermal earth source
loop
23
CA 02526356 2005-11-14
can be less than conventional ground loop depth, reducing costs and increasing
qualifying sites. Second, by reducing the power requirements of the compressor
and
eliminating ground loop circulating pumps, the power requirements of the
geothermal
cooling device are substantially less than conventional geothermal exchange
units,
whether central or for a single room, and permit the installation and
operation on normal
household circuits such as a 15 Ampere rated outlet. Third, the lightweight
and small
size of the exchange coil housing relative to existing solutions, permits easy
installation
in a wide range of locations and even installations of individual exchange
units in
multiple rooms of a residence interior. Fourth, due to eliminating ground loop
refrigerant
and associated high power circulation pumps, system lifetimes are extended
beyond
conventional geoexchange.
The superconductor geothermal exchange system 110 of Figure 1 can be
configured for heating and cooling a secondary liquid such as water, liquid
solutions and
the like, as shown in Figures 4, 5 and 6. In Fig 4, superconductor geothermal
exchange system 130 is designed for heating and cooling a secondary fluid 82
for use
inside a structure, for example to heat domestic water or to heat water in a
hydronic
radiant floor, with the following modifications and additions. Heat exchanger
element 38
is immersed in a fluid 82 in tank 80 for the purpose of transferring heat to
and from fluid
82. Fluid 82 is stored in tank 80 in a volume resulting in a thermal mass and
having
storage temperature measured by sensor 84 connected to controller 16. The
space heat
exchanger 38 is arranged in the tank in contact with the exchange fluid 82, as
shown.
The fluid in the tank is circulated by a pump (not shown) out to a remote
exchange
location through outlet 88 and returned to the tank 80 through inlet 86 with
resultant
change in fluid temperature. For this case, the remote exchange may be fluid-
to-air,
fluid-to-liquid or fluid to solid thermal mass and have an associated
temperature sensor
(not shown). Controller 16 is connected to operate power pump (not shown) for
circulation of secondary fluid, in combination with operating the
superconductor
geothermal exchange system in heating or cooling modes as previously
described.
24
CA 02526356 2005-11-14
Figure 5 shows another alternative configuration of geothermal exchange
system 130 in which a fluid heat exchanger is configured to provide indirect
heat
transfer to and from an auxiliary fluid loop. In this configuration, heat
exchanger 38 is
immersed in a non-circulating heat transfer fluid 87 in a tank 85. A secondary
circulating fluid enters tank 85 through fluid inlet 81 and passes through
heat exchange
loop 89, absorbing heat from heat transfer fluid 87 (in the heating mode) or
giving up
heat (in the cooling mode) before exiting tank 85 through fluid outlet 83.
Figure 6 shows another alternative configuration of geothermal exchange
system 130 in which fluid heat exchanger 104 is configured to provide direct
thermal
transfer between heat exchange element 38 and a fluid loop 75 through thermal
contact
between the element and loop. In this configuration, a fluid (not shown) such
as water, a
liquid solution or a refrigerant is circulated by a separate system (not
shown) and
passes through fluid loop 75, transferring heat through the walls of fluid
loop 75 walls,
to or from heat exchange element 38 directly. As known to one skilled in the
art of heat
transfer, such thermal contact can be provided by metal-metal contact or by
contact with
an intermediate, localized heat transfer component such as a thermal paste and
the
like.
The above ground components of the geothermal exchange systems
described in Figures 1 to 6 can be grouped in plurality of separate housings
as shown in
Figs 7 and 8. Figure 7a illustrates one embodiment of a such split system in
which
remote housing 92 encloses the space heat exchanger 38, blower 54 expansion
valve
62a and associated inlet and outlet conduit to transfer the incoming and
outgoing
refrigerant with the other components in the refrigerant loop. Optionally,
drip tray and
line 56, 58 and temperature sensor 26 may be included. There are three
advantages to
a split housing. First, installation may be made easier by placing the
elements coupled
to the ground superconductor outside. Second, there is an advantage to housing
the
noisy components such as the compressor in a separate housing such that the
noise
level in the heating space is reduced. Third, as the compressor produces heat
while
operating, there is an advantage to having it outside rather than having the
extra heat
CA 02526356 2005-11-14
discharged into the space being cooled, reduce efficiency of the cooling mode.
Further,
the housing 12 could be located centrally in a structure, with enclosure 52
located
remotely in a space to be heated or cooled, as shown by the example of
enclosure 92 in
Fig 7b. Alternatively, housing 12 could be located exterior to a structure and
connected
through superconductor transfer segment 38 to enclosure 52 located inside the
structure to be heated or cooled.
Figure 8 illustrates an alternate exchange configuration in which heat
exchanger 66 and related components are enclosed in enclosure 94 such that
heat
exchange between ground loop 48 and the refrigerant loop is accomplished
outside
enclosure 12, allowing ground heat exchanger 66 to be located at any point
below, at or
above ground level, making system installation more flexible. Optional
connectors 96
and 96a enable simplified interconnection of system components in some
applications.
Figure 9 illustrates an embodiment of the invention in which heat is
transferred in a heating only mode using a thermal superconducting medium,
such as
described above, for a superconductor geothermal heating device 150.
Generally, heat
is transferred from a thermal superconductor earth source loop by a thermal
superconductor heat exchange coil configured through a refrigerant loop
subsystem.
Specifically, superconductor geothermal exchange active components are
positioned
above ground level 46 and couplable to a geothermal ground loop 48 formed from
thermal superconductor and positioned in a ground loop hole 50. The ground
loop
refrigerant or coolant circulating loops of conventional geoexchange systems
are
replaced with thermally superconducting transfer coils that are operable bi-
directionally,
resulting in many advantages of efficiency, reduced size, and fewer
components. The
ground loop thermal superconductor extends above ground level where it is
covered by
insulation 25 and terminated in a coupler 44. For illustrative purposes, this
superconductor may be in the form of a sealed metal tube as currently
available from
Qu Corporation and will be preferred to be in tube form. Alternatively other
available
thermal superconductors could be similarly substituted that may have various
forms and
26
CA 02526356 2005-11-14
cross sections such as flexible conduits, thin laminate, thin film coated
metal etc, that
may be suitable depending on the site and system conditions.
The superconductor segment 40 extends to be in thermal contact to an
evaporator exchanger 68 of a refrigerant loop that functions to circulate heat
transferred
from the ground loop. The refrigerant loop circuit forms a refrigerant
transfer path which
includes a compressor 20 having outlet connected to refrigerant conduit 22 to
condenser heat exchanger 74 to a conduit 32 connected to an expander 62 with
conduit
64 to evaporator heat exchanger 72 connected to a return conduit 34, through
an
optional accumulator 23 to a return conduit 24 to the inlet of the compressor
20.
When the refrigerant loop as described is filled with a suitable amount of
refrigerant, the refrigerant heat exchange circuit is operated by powering on
the
compressor. In a the heating mode, the compressor 20 compresses a gaseous
refrigerant to intensify its heat content, circulates it through conduit 22 to
the condenser
heat exchanger 74 where the hot refrigerant vapor gives up heat and condenses
to a
liquid or partial liquid before passing through conduit 60 to expander 62
where the liquid
refrigerant is expanded in a pressure drop to change state, becoming cooled
vapor
which enters evaporator heat exchanger 72 and absorbs heat from the ground
loop
before passing through return conduit 34 to optional accumulator 23 (where any
remaining liquid is trapped and vaporized) before the refrigerant transfers
through
conduit 24 to complete the loop at the compressor inlet. This creates a
temperature
differential between the condenser heat exchanger 74 and evaporator heat
exchanger
72. In the preferred case, heat exchangers 74 and 72 are isolated by
insulation 25 (not
shown.) A thermal sensor 18 is associated with the medium to be conditioned by
condenser heat exchanger 74. A controller 16 is powered by power line 14 and
provides
power to compressor 20 and reversing valve 28, as well as control data to and
from
thermal sensor 26. Condenser heat exchanger 74 can be configured in any
geometric
arrangement related to a structure to optimize heat transfer to a specific
medium.
Insulation 25 also preferably covers superconductor transfer segments outside
of
coupling connections and heat exchange sections, to reduce thermal transfer
losses.
27
CA 02526356 2005-11-14
The superconductor geothermal exchange system 150 is operable
depending on the difference between the actual measured temperature and a
desired
set-point programmed in the thermostatic controller 16. For example, when the
desired
temperature is higher than actual temperature the superconductor geothermal
exchange system 150 is operated. Heat is then efficiently transferred from
ground loop
48 to the evaporator heat exchanger 72, then efficiently transferred through
the
refrigerating loop to condenser heat exchanger for related heating use.
The superconductor geothermal exchange system 150 attached to
segment 40 above coupler 44 can be enclosed a number of ways, depending on
application. For example all components as shown could be housed inside one
enclosure 12. Alternatively thermal superconductor segments 40 and 42 can be
installed at a later time. As obvious to one skilled in the art, the coupler
44 could
equivalently be alternatively positioned under the ground, above ground
outside a
structure, inside a structure but outside the housing 12, or even inside the
housing 12,
as selected for best ease of installation. Housing 12 may include ambient
vents for
convective cooling of the compressor. A further embodiment of the
superconductor
geothermal exchange system 150 can eliminate the coupler 44 by configuring the
switch to have a ground loop receptacle to accept the termination of the
superconductor
ground loop 48 such that the ground loop 48 can be separately installed from
the rest of
the system.
The superconductor geothermal heating device 150 of Figure 9, can be
configured for air heating as shown in Figure 10. Superconductor geothermal
heating
device 160 is designed for air heating inside a structure, with the following
modifications
and additions. Enclosure 12 has two vented regions to provide an inlet and
outlet for
circulated air. Between the two vented regions is the evaporator exchanger 38,
which is
further insulated by insulation 25 up to the coil. A blower 54 is positioned
in proximity to
the evaporator heat exchanger 74 to pull or push air through the exchanger for
heating,
the preferred position being near the outlet vent region such that air is
pulled over heat
28
CA 02526356 2005-11-14
exchanger 74. The fan can be a low power, low throughput fan to conserve
energy, or
alternatively a variable speed fan. The preferred fan has operating noise less
than 45
dB and can be DC powered by an alternative energy source (not shown).
Evaporator
heat exchanger 74 may be configured in many possible designs provided
sufficient net
surface area is exposed to the air flow; the illustration of an array of bars
substantially
corresponding to the fan diameter, is a preferred example. Alternatively, as
is well
known in the art of air heat exchangers, metal fins could be added to increase
the
surface area of the heat exchanger. Blower 54 is connected to controller 16
and power
line 14 for control of fan operation.
The controlled operation of the superconductor geothermal exchange
system 160 is essential for user comfort and control of heating. Controller 16
may be
programmed as a thermostat controller responding to a temperature sensor 26
(such as
a thermocouple) associated with the space to be heated, or as a controller
that receives
input from a remote thermostat and sensor associated with the space (not
shown). The
controller is shown within the housing 12, but may alternatively be in any
location
provided it is in communication with the blower and temperature sensor. While
the
simplest implementation is one temperature measurement, to one skilled in the
art,
multiple temperature measurements could be weighted or averaged for the
purpose of
feedback set points in the controller 16. In the case of a multi-speed fan,
alternatively a
second temperature sensor could be positioned on or near the space heat
exchanger
74 to determine the initial fan speed for faster heating. Unlike conventional
central
geothermal heat pumps, which are large, noisy and require greater power than
available
from a standard household outlet, the air exchange subsystem in enclosure 60
can be
operated from a standard power outlet, anywhere in the house, quietly and in a
small
form factor housing. The housing 60 for air exchange subsystem, may be
positioned
anywhere within the interior room to be heated, and does not have to be near
an
exterior wall or window. Preferably the housing is positioned to provide
optimum air
mixing and heating or cooling for the room.
29
CA 02526356 2005-11-14
Operating mode is similar as described for Figure 9, with the additional
mode of operating the blower in combination with operating the compressor for
improving the rate of heat exchange with the air space to be conditioned. With
the
controller 16 set to a desired room temperature T1, via a manual input (not
shown), or a
remote control input, or a second remote thermostat (not shown) in
communication with
the controller 16, the controller senses existing room temperature T2 and if
lower than
T1, operates the compressor 20 to circulate heated refrigerant and operates
blower 54
to circulate air until the temperature reaches T1. Alternatively, as common in
the art,
various thresholding or smoothing processes can be programmed to avoid jitter
and
determine when to switch the blower 54 on or off. In the example of a multi-
speed
blower, the blower speed can be programmed to change in response to the rate
of
change of existing temperature T2, in addition to on or off. The
superconductor
geothermal exchange system 160 can be programmed to operate for any input that
acts
as a related proxy for associated interior temperature and has a known
characterized
relationship to temperature.
A further embodiment of the superconductor geothermal exchange system
160 can eliminate the coupler 44 by configuring the evaporator heat exchanger
68 to
have a receptacle portion to accept the termination of the superconductor
ground loop
48, such that the ground loop 48 can be separately installed from the rest of
the system.
It will be obvious to one skilled in the art that there are many equivalent
designs to
couple the ground loop superconductor to the switch including intermediate
coupler
segments.
The superconductor geothermal heating devices of figures 9 and 10 have
many advantages that solve the problems described in the background, due to
the
substantial efficiency increase relative to existing geothermal heating
solutions. These
efficiency gains result in coefficient of performance of greater than 2 and
potentially as
high as 5 or more, beyond the limits of conventional geothermal heating.
First, by
increasing system efficiency, the hole depth of the geothermal earth source
loop can be
less than conventional ground loop depth, reducing costs and increasing
qualifying
CA 02526356 2005-11-14
sites. Second, by reducing the power requirements of the compressor and
eliminating
ground loop circulating pumps, the power requirements of the geothermal
cooling
device are substantially less than conventional geothermal exchange units,
whether
central or for a single room, and permit the installation and operation on
normal
household circuits such as a 15 Ampere rated outlet. Third, the lightweight
and small
size of the exchange coil housing relative to existing solutions, permits easy
installation
in a wide range of locations and even installations of individual exchange
units in
multiple rooms of a residence interior. Fourth, due to eliminating ground loop
refrigerant
and associated high power circulation pumps, system lifetimes are extended
beyond
conventional geoexchange.
The superconductor geothermal heating device 150 of Figure 9, can be
configured for heating a secondary liquid such as water, liquid solutions and
the like, as
shown in Figures 11, 12 and 13. In Figure 11, superconductor geothermal
exchange
system 170 is designed for heating and cooling a secondary exchange fluid 82
for use
inside a structure, with the following modifications and additions to heating
device 150.
Heat exchanger element 38 is immersed in a fluid 82 in tank 80 for the purpose
of
transferring heat to and from fluid 82. Fluid 82 is stored in tank 80 in a
volume resulting
in a thermal mass and having storage temperature measured by sensor 84
connected
to controller 16. The space heat exchanger 38 is arranged in the tank in
contact with the
exchange fluid 82, as shown. The fluid in the tank is circulated by a pump
(not shown)
out to a remote exchange location through outlet 88 and returned to the tank
80 through
inlet 86 with resultant change in fluid temperature. For this case, the remote
exchange
may be fluid-to-air, fluid-to-liquid or fluid to solid thermal mass and have
an associated
temperature sensor (not shown). Controller 16 is connected to operate power
pump
(not shown) for circulation of secondary fluid, in combination with operating
the
superconductor geothermal exchange system in heating or cooling modes as
previously
described.
Alternatively, as shown in Figure 12, a fluid heat exchanger can be
configured to provide indirect heat transfer to and from an auxiliary fluid
loop. In this
31
CA 02526356 2005-11-14
configuration, heat exchanger 38 is immersed in a non-circulating heat
transfer fluid 87
in a tank 85. A secondary circulating fluid (not shown) enters tank 85 through
fluid inlet
81 and passes through heat exchange loop 89, absorbing heat from heat transfer
fluid
87 (in the heating mode) or giving up heat (in the cooling mode) before
exiting tank 85
through fluid outlet 83.
Figure 13 shows another alternative configuration in which the fluid heat
exchanger is configured to provide direct thermal transfer between heat
exchange
element 38 and a fluid loop 75 through thermal contact between the two
elements. In
this configuration, a fluid (not shown) such as water, a liquid solution or a
refrigerant is
circulated by a separate system (not shown) and passes through fluid loop 75,
transferring heat through the walls of fluid loop 75 walls, to or from heat
exchange
element 38 directly. As known to one skilled in the art of heat transfer, such
thermal
contact can be provided by metal-metal contact or by contact with an
intermediate,
localized heat transfer component such as a thermal paste and the
like.Exchange fluid
is typically in exchange with a second liquid or air exchanger for use in
heating such as
floor or radiator heating, domestic water heating. Fluid may alternatively be
distributed
and circulated for distributed exchange.
The above ground components of the geothermal exchange systems
described in Figures 9 to 13 can be grouped in plurality of separate housings
as shown
in Figs 14a,b and 15. Figure 14a illustrates an embodiment in which the
condenser
exchanger is located remotely in housing 92. Housing 92 encloses the condenser
exchanger 74, blower 54, expansion valve 62a and associated inlet and outlet
conduit
to transfer the incoming and outgoing refrigerant with the other components in
the
refrigerant loop. Optionally, temperature sensor 26 may be included. There are
two
advantages to a split housing. First, installation may be made easier by
placing the
elements coupled to the ground superconductor outside. Second, there is an
advantage
to housing the noisy components such as compressor in a separate housing such
that
the noise level in the heating and cooling space is reduced. Further, the
housing 12
could be located centrally in a structure, with enclosure 52 located remotely
in a space
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CA 02526356 2005-11-14
to be heated, as shown by the example of enclosure 92 in Fig 14b.
Alternatively,
housing 12 could be located exterior to a structure and connected through
superconductor transfer segment 38 to enclosure 52 located inside the
structure to be
heated. Similarly, as shown in Figure 15, split housing enclosures can be
configured for
alternate exchange configurations with the appropriate relocation of heat
exchange
related components. In this figure, heat exchanger 66 and related components
are
enclosed in enclosure 94 such that heat exchange between ground loop 48 and
the
refrigerant loop happens outside enclosure 12, allowing ground heat exchanger
66 to be
located at any point below, at or above ground level, making system
installation more
flexible. Optional connectors 96 and 96a enable simplified interconnection of
system
components in some applications.
Figure 16 illustrates an embodiment of the invention in which heat is
transferred in a cooling only mode, using a thermal superconducting medium
such as
described above, for a superconductor geothermal cooling device 190.
Generally, heat
is transferred to a thermal superconductor earth source loop by a thermal
superconductor heat exchange coil configured through a refrigerant loop
subsystem.
Specifically, superconductor geothermal exchange active components are
positioned
above ground level 46 and couplable to a geothermal ground loop 48 formed from
thermal superconductor and positioned in a ground loop hole 50. The ground
loop
refrigerant or coolant circulating loops of conventional geoexchange systems
are
replaced with thermally superconducting transfer coils that are operable bi-
directionally,
resulting in many advantages of efficiency, reduced size, and fewer
components. The
ground loop thermal superconductor extends above ground level where it is
covered by
insulation 25 and terminated in a coupler 44. For illustrative purposes, this
superconductor may be in the form of a sealed metal tube as currently
available from
Qu Corporation and will be preferred to be in tube form. Alternatively other
available
thermal superconductors could be similarly substituted that may have various
forms and
cross sections such as flexible conduits, thin laminate, thin film coated
metal etc, that
may be suitable depending on the site and system conditions.
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CA 02526356 2005-11-14
The superconductor segment 40 extends to be in thermal contact to a
condenser exchanger 68 of a refrigerant loop that functions to circulate heat
to the
ground loop. The refrigerant loop circuit forms a refrigerant transfer path
which includes
a compressor 20 having outlet connected to refrigerant conduit 22 to a
condenser
exchanger 76 to a conduit 32 connected to an expander 62 with conduit 64 to an
evaporator exchanger 78 connected to a return conduit 34, through an optional
accumulator 23 to a return conduit 24 to the inlet of the compressor 20.
When the refrigerant loop as described is filled with a suitable amount of
refrigerant, the refrigerant heat exchange circuit is operated by powering the
compressor. In a cooling mode, the compressor 20 compresses a gaseous
refrigerant
to intensify its heat content, circulates it through conduit 22 to the
condenser exchanger
76 where it gives up heat to the ground loop acting as a condenser, and then
passes
through conduit 60 to expander 62 which rapidly expands liquid in a pressure
drop to
change the refrigerant state to cooled vapor which absorbs heat at the
evaporator
exchanger 78 before passing through return conduit 34 to optional accumulator
23
(where any remaining liquid is trapped and vaporized) and remaining
refrigerant
transfers through conduit 24 to complete the loop at the compressor inlet.
This creates a
temperature differential between evaporator exchanger 78 and condenser
exchanger
76. In the preferred case, the refrigerant heat exchangers are isolated by
insulation 25
as shown. A thermal sensor 18 is associated with the medium to be conditioned
by
evaporator exchanger 78. A controller 16 is powered by power line 14 and
provides
power to compressor 20 and reversing valve 28, as well as control data to and
from
thermal sensor 26. Evaporator exchanger 78 can be configured in any geometric
arrangement related to a structure to optimize heat transfer to a specific
medium.
Insulation 25 also preferably covers superconductor transfer segments outside
of
coupling connections and heat exchange sections, to reduce thermal transfer
losses.
The superconductor geothermal cooling device 190 is controlled
depending on the difference between the actual measured temperature and a
desired
set-point programmed in the thermostatic controller 16. For example, when the
desired
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CA 02526356 2005-11-14
temperature is lower than actual temperature the superconductor geothermal
cooling
device 190 is operated in a cooling mode. In cooling mode, heat is collected
at the
condenser exchanger, transferred through the refrigerating loop then
efficiently
transferred to ground loop 48 from the condenser exchanger 76, for related
cooling
use.
The superconductor geothermal cooling device 190 attached to segment
40 above coupler 44 can be enclosed a number of ways, depending on
application. For
example all components as shown could be housed inside one enclosure 12.
Alternatively thermal superconductor segments 40 and 42 can be installed at a
later
time. As obvious to one skilled in the art, the coupler 44 could equivalently
be
alternatively positioned under the ground, above ground outside a structure,
inside a
structure but outside the housing 12, or even inside the housing 12, as
selected for best
ease of installation. Housing 12 may include ambient vents for convective
cooling of the
compressor. A further embodiment of the superconductor geothermal cooling
device
190 can eliminate the coupler 44 by configuring the switch to have a ground
loop
receptacle to accept the termination of the superconductor ground loop 48 such
that the
ground loop 48 can be separately installed from the rest of the system.
The superconductor geothermal cooling device 190 of Figure 16, can be
configured for air cooling as shown in Figure 17. Superconductor geothermal
cooling
system 200 is designed for air cooling inside a structure, with the following
modifications
and additions. Enclosure 12 has two vented regions to provide an inlet and
outlet for
circulated air. Between the two vented regions is the evaporator exchanger 78,
which is
further insulated by insulation 25 up to the coil. A blower 54 is positioned
in proximity to
the evaporator exchanger 78 to pull or push air through the exchanger for
cooling, the
preferred position being near the outlet vent region such that air is pulled
over the
evaporator exchanger 78. The fan can be a low power, low throughput fan to
conserve
energy, or alternatively a variable speed fan. The preferred fan has operating
noise less
than 45 dB and can be DC powered by an alternative energy source (not shown).
Evaporator exchanger 78 may be configured in many possible designs provided
CA 02526356 2005-11-14
sufficient net surface area is exposed to the air flow; the illustration of an
array of bars
substantially corresponding to the fan diameter, is a preferred example.
Alternatively, as
is well known in the art of air heat exchangers, metal fins could be added to
increase
the surface area of the heat exchanger. Blower 54 is connected to controller
16 and
power line 14 for control of fan operation. Under some ambient conditions,
condensate
will form on the evaporator exchanger 78, and an optional drip tray 56 is
shown
positioned below to catch condensate and an optional water drain line 58 is
shown
connected to drip tray for runoff disposal.
The controlled operation of the superconductor geothermal cooling device
200 is essential for user comfort and control of cooling. Controller 16 may be
programmed as a thermostat controller responding to a temperature sensor 26
(such as
a thermocouple) associated with the space to be heated, or as a controller
that receives
input from a remote thermostat and sensor associated with the space (not
shown). The
controller is shown within the housing 12, but may alternatively be in any
location
provided it is in communication with the blower and temperature sensor. While
the
simplest implementation is one temperature measurement, to one skilled in the
art,
multiple temperature measurements could be weighted or averaged for the
purpose of
feedback set points in the controller 16. In the case of a multi-speed fan,
alternatively a
second temperature sensor could be positioned on or near the space heat
exchanger
38 to determine the initial fan speed for faster cooling. Unlike conventional
central
geothermal heat pumps, which are large, noisy and require greater power than
available
from a standard household outlet, the air exchange subsystem in enclosure 12
can be
operated from a standard power outlet, anywhere in the house, quietly and in a
small
form factor housing. Preferably the housing is positioned to provide optimum
air mixing
and cooling for the room.
Operating modes are similar as described for figure 16, with the additional
mode of operating the blower in combination with operating the compressor for
improving the rate of heat exchange with the air space to be conditioned. With
the
controller 16 set to a desired room temperature T1, via a manual input (not
shown), or a
36
CA 02526356 2005-11-14
remote control input, or a second remote thermostat (not shown) in
communication with
the controller 16, the controller senses existing room temperature T2 and if
higher than
T1, operates the compressor 20 to circulate heated refrigerant and operates
biower 54
to circulate air until the temperature reaches T1. Alternatively, as common in
the art,
various thresholding or smoothing processes can be programmed to avoid jitter
and
determine when to switch the blower 54 on or off. In the example of a multi-
speed
blower, the blower speed can be programmed to change in response to the rate
of
change of existing temperature T2, in addition to on or off, such that cooling
device 200
maintains optimal thermal comfort in a space while minimizing fan noise,
compressor
noise and system cycling. The superconductor geothermal cooling device 200 can
also
be programmed to operate for any input that acts as a related proxy for
associated
interior temperature and has a known characterized relationship to
temperature.
A further embodiment of the superconductor geothermal cooling device
200 can eliminate the coupler 44 by configuring the condenser exchanger 76 to
have a
receptacle portion to accept the termination of the superconductor ground loop
48, such
that the ground loop 48 can be separately installed from the rest of the
system. It will be
obvious to one skilled in the art that there are many equivalent designs to
couple the
ground loop superconductor to the switch including intermediate coupler
segments.
The above ground components of the geothermal exchange systems
described in Figures 16 to 17 can be grouped in plurality of separate housings
as shown
in Figs 18a,b and 19. Figure 18aa illustrates an embodiment in which the
condenser
exchanger is located remotely in housing 92. Housing 92 encloses the condenser
exchanger 74, blower 54 expansion valve 62a and associated inlet and outlet
conduit to
transfer the incoming and outgoing refrigerant with the other components in
the
refrigerant loop. Optionally, drip tray and line 56, 58 and temperature sensor
26 may be
included. There are three advantages to a split housing. First, installation
may be made
easier by placing the elements coupled to the ground superconductor outside.
Second,
there is an advantage to housing the noisy components such as compressor in a
separate housing such that the noise level in the heating and cooling space is
reduced.
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CA 02526356 2005-11-14
Third, as the compressor produces heat while operating, there is an advantage
to
having it outside rather than having the extra heat reduce effectiveness of
cooling the
space in cooling mode. Further, the housing 12 could be located centrally in a
structure,
with enclosure 52 located remotely in a space to be heated, as shown by the
example
of enclosure 92 in Fig 18b.. Alternatively, housing 12 could be located
exterior to a
structure and connected through superconductor transfer segment 38 to
enclosure 52
located inside the structure to be heated. Similarly, as shown in Figure 19,
split
enclosures can be configured for alternate exchange configurations with the
appropriate
relocation of heat exchange related components. In this figure, heat exchanger
66 and
related components are enclosed in enclosure 94 such that heat exchange
between
ground loop 48 and the refrigerant loop happens outside enclosure 12, allowing
ground
heat exchanger 66 to be located at any point below, at or above ground level,
making
system installation more flexible. Optional connectors 96 and 96a enable
simplified
interconnection of system components in some applications.
The superconductor geothermal cooling devices of Figures 16 to 19 have
many advantages that solve the problems described in the background, due to
the
substantial energy efficiency and cost efficiency increases relative to
existing
geothermal cooling solutions. These efficiency gains result in coefficient of
performance
of greater than 2 and potentially as high as 5 or more, beyond the limits of
conventional
geothermal cooling. First, the hole depth of the geothermal earth source loop
can be
less than conventional ground loop depth, reducing costs and increasing
qualifying
sites. Second, by reducing the power requirements of the compressor and
eliminating
ground loop circulating pumps, the power requirements of the geothermal
cooling
device are substantially less than conventional geothermal exchange units,
whether
central or for a single room, and permit the installation and operation on
normal
household circuits such as a 15 Ampere rated outlet. Third, the lightweight
and small
size of the exchange coil housing relative to existing solutions, permits easy
installation
in buildings. Fourth, due to eliminating ground loop refrigerant and
associated high
power circulation pumps, system lifetimes are extended beyond conventional
geoexchange.
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CA 02526356 2005-11-14
The thermal superconductor geoexchange systems and heating and
cooling devices described herein are couplable or connectable to a thermal
superconductor element. The systems may be assembled from subsystems having no
thermal superconductor elements, but with the addition of a superconductor
heat
exchange interconnect thermally coupled to ground loop heat exchanger 68, 72
or 76.
The heat exchange interconnect preferably limits any increase in heat transfer
resistance to less than 15% when connected to a thermal superconductor, and is
easily
coupled to a tube or rod shaped thermal superconductor.
Examples of such interconnections are shown in Figures 20a,b,c. Figure 20a
illustrates a geothermal heating and cooling system 200 couplable to a
superconducting
earth source ground loop through superconductor heat exchange interconnect
102. Fig
20b illustrates one embodiment of such a ground source heat exchanger
incorporating
superconductor heat exchange interconnect 102 in the form of a tubular opening
in a
metal block that is coupled with heat exchanger x. This tubular opening has a
diameter
slightly larger than corresponding uninsulated thermal superconductor tube 42,
such
that when thermal superconductor tube 42 is inserted in the hole, it directly
contacts the
surface of the metal block and heat is transferred between the superconductor
tube and
the heat exchanger. The tube may have securing clamps on at least one side to
maintain the thermal superconductor from moving. Figure 20c shows an alternate
embodiment of the coupling shown in figure 20b. In this embodiment, the
diameter of
the tubular opening that forms superconductor heat exchange interconnect 102
is
significantly larger than the corresponding thermal superconductor tube 42
such that
when the superconductor tube is inserted in the hole, a gap is formed between
the
superconductor tube and the walls of the tubular hole. When the gap is filled
with a
thermal paste, heat is transferred between the thermal superconductor tube and
the
heat exchanger through the thermal paste. As will be obvious to one skilled in
the art of
using thermal paste and other such intermediating thermal transfer substances,
it may
be necessary to provide a seal at the opening of superconductor heat exchange
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CA 02526356 2005-11-14
interconnect 102 to keep the thermal paste in the gap between the thermal
transfer
surfaces.
Figure 21 shows two alternative configurations for coupling
superconductor heat exchange interconnect 102 and ground loop heat exchangers
68,
72 or 76. In Figure 21a, a heat exchange coil is arranged in a tight wound
coil around
superconductor heat exchange interconnect 102 which is configured as a metal
tube
having an opening to receive a tubular superconductor segment. In Figure 21 b,
the heat
exchanger is configured as a sleeve with a cavity suitable for receiving a
thermal
superconductor tube, with the refrigerant flowing through the sleeve to
transfer heat
through the inner sleeve surface. At the sleeve cavity opening, there maybe a
refrigerant collector to couple the refrigerant to the exchange loop. The
interconnect
may have multiple sleeve openings for coupling multiple thermal superconductor
ground
loops. The thermal interconnect will be preferably rigid to maintain uniform
flow
conditions for the refrigerant.
Figure 22 illustrates a geothermal heating system 210 suitable for coupling
to a superconducting earth source ground loop through superconductor heat
exchange
interconnect 102 in the same manner described in Figure 20 for system 200.
System
210, when coupled to superconductor ground loop, can be operated and
additionally
configured with reference to figures 9-15.
Figure 23 illustrates a geothermal cooling system 220 suitable for coupling
to a superconducting earth source ground loop through superconductor heat
exchange
interconnect 102 in the same manner described in Figure 20 for system 200.
System
220, when coupled to superconductor ground loop, can be operated and
additionally
configured with reference to figures 16-19.
Throughout these examples and embodiments described, insulation has
been shown on superconductor segments which function to transfer heat
internally from
one location to another, and insulation is not shown on ends of these segments
which
CA 02526356 2005-11-14
function to transfer heat to air, fluids or other or other system components.
This is the
preferred example, whether or not explicitly stated in figure descriptions or
numbered on
drawings. However, as noted previously, the superconductor geothermal cooling
devices described will operate with no insulation or with some transfer lines
insulated or
any combination of insulated or uninsulated portions of the superconductors
thereof.
Throughout these examples housing has been described as split housing
in a preferred case, however it will be appreciated that the various
embodiments can be
integrated into existing structures or enclosed in a single housing.
41
