U.S. patent application number 11/401718 was filed with the patent office on 2007-10-11 for building source heat pump.
This patent application is currently assigned to Vintage Construction & Dev. Co.. Invention is credited to Chad Phillips.
Application Number | 20070235179 11/401718 |
Document ID | / |
Family ID | 38573920 |
Filed Date | 2007-10-11 |
United States Patent
Application |
20070235179 |
Kind Code |
A1 |
Phillips; Chad |
October 11, 2007 |
Building source heat pump
Abstract
An energy efficient heating and cooling system is defined by a
closed loop coil system of conduit in which the tubing through
which fluid flows is located to the interior of the structure,
preferably above the winter-heated space and below an insulated
roof or in a multi-level building floor, so that heat rising to the
ceiling may be recovered in a geothermal heat pump. The structure
source loop may be combined with an optional ground source loop. A
furnace controls the flow of heated air into the structure and
supplies supplemental heat and the system is under the control of a
microprocessor.
Inventors: |
Phillips; Chad; (Bend,
OR) |
Correspondence
Address: |
HANCOCK HUGHEY LLP
P.O. BOX 1208
SISTERS
OR
97759
US
|
Assignee: |
Vintage Construction & Dev.
Co.
|
Family ID: |
38573920 |
Appl. No.: |
11/401718 |
Filed: |
April 11, 2006 |
Current U.S.
Class: |
165/244 ;
165/254; 165/48.1 |
Current CPC
Class: |
F24F 5/0046 20130101;
F24F 12/00 20130101; F24F 2005/0053 20130101; F24F 3/001 20130101;
F25B 30/06 20130101; Y02B 10/24 20130101; F24F 2005/0057 20130101;
Y02B 10/40 20130101; Y02A 30/272 20180101; Y02B 10/20 20130101 |
Class at
Publication: |
165/244 ;
165/254; 165/048.1 |
International
Class: |
F25B 29/00 20060101
F25B029/00; F24F 11/04 20060101 F24F011/04 |
Claims
1. A heating and cooling system for a structure having a heated
interior space and a roof, comprising: a furnace; a heat exchanger;
a fan for inducing a flow of air from the heat exchanger to the
interior space; a first conduit capable of conducting a flow of a
heat exchange medium, said first conduit operatively connected to
the heat exchanger for conducting the heat exchange medium through
the heat exchanger, and said first conduit including a length of
conduit located between the heated interior space and the roof; and
insulation between the conduit and the roof.
2. The heating and cooling system according to claim 1 including a
thermostat in the heated interior space and a first temperature
sensor located between the heated interior space and the roof, a
pump for inducing a flow of the heat exchange medium through the
first conduit and a controller in communication with the thermostat
and the first temperature sensor, said controller configured for
operation of the furnace, the fan, the heat exchanger and the
pump.
3. The heating and cooling system according to claim 2 wherein said
controller further includes a microprocessor configured for
comparing temperature data from the thermostat and the first
temperature sensor, and for operating the furnace, heat exchanger
and pump if the difference between the temperature at the
thermostat and the temperature at the first temperature sensor
exceeds a predetermined minimum.
4. The heating and cooling system according to claim 2 including a
second conduit for conducting a flow of a heat exchange medium,
said second conduit operatively connected to the heat exchanger and
a pump for conducting the heat exchange medium through the heat
exchanger, and said second conduit including a length of conduit
buried in the ground and a second temperature sensor buried in the
ground and in communication with the controller.
5. The heating and cooling system according to claim 4 wherein said
controller includes a flow controller and the first conduit and
second conduit are operatively connected to the flow controller,
and said flow controller is in operative communication with said
microprocessor, whereby said microprocessor is capable of selecting
either said first conduit or said second conduit.
6. The heating and cooling system according to claim 5 wherein said
controller is configured for comparing temperature data from the
thermostat and the first and second temperature sensors, and for
selecting either the first conduit or second conduit based on
predetermined criteria and operating the furnace, the fan, the heat
exchanger and pump in response to the selection.
7. The heating and cooling system according to claim 6 wherein said
controller selects the first conduit if the difference between the
temperature at the thermostat and the temperature at the first
temperature sensor exceeds a predetermined minimum.
8. The heating and cooling system according to claim 6 wherein said
controller selects the second conduit if the difference between the
temperature at the thermostat and the temperature at the second
temperature sensor exceeds a predetermined minimum, and the
temperature at the second temperature sensor is greater than the
temperature at the first temperature sensor.
9. A method of recovering heat in a structure having a heated
interior space, an insulated roof above the heated interior space,
and a furnace, comprising the steps of: (a) installing a first
conduit above the heated interior space and below the insulated
roof; (b) operatively connecting said first conduit to a heat
exchanger and operatively connecting said heat exchanger to said
furnace; (c) inducing a flow of a heat exchange medium through said
first conduit so that the temperature of said heat exchange medium
is raised as it flows through said conduit, and circulating said
heat exchange medium through said heat exchanger; (d) extracting
heat from said heat exchange medium in said heat exchanger to warm
air; and (e) inducing a flow of said warmed air into said heated
interior space.
10. The method according to claim 9 including the steps of: (a)
measuring the temperature in the heated interior space; (b)
measuring the temperature above the heated interior space and below
the roof; (c) comparing the temperatures measured in steps (a) and
(b) and in response thereto, determining if a flow of the heat
exchange medium should be induced through the first conduit.
11. The method according to claim 9 wherein if the difference
between the temperature measured at steps (a) and (b) exceeds a
predetermined minimum, inducing a flow of the heat exchange medium
to increase the temperature of the heat exchange medium, extracting
heat from the heat exchange medium in the heat exchanger to warm
air, and operating said furnace to induce a flow of said warmed air
into said heated interior space.
12. The method according to claim 11 wherein if the difference
between the temperature measured at steps (a) and (b) is below the
predetermined minimum, the furnace is operated to heat the heated
interior space.
13. The method according to claim 9 including the steps of: (a)
installing a second conduit in the ground; (b) operatively
connecting said second conduit to the heat exchanger; (c) placing
the first and second conduits, the furnace and the heat exchanger
under the control of a controller; (d) causing the controller to
select either the first or the second conduit in and inducing a
flow of a heat exchange medium through the selected first or second
conduit so that the temperature of said heat exchange medium in
said selected conduit is raised as it flows through said selected
conduit, and circulating said heat exchange medium through said
heat exchanger; (e) extracting heat from said heat exchange medium
in said heat exchanger to warm air; and (f) inducing a flow of said
warmed air into said heated interior space.
14. The method according to claim 13 including the steps of: (a)
measuring the temperature in the heated interior space; (b)
measuring the temperature above the heated interior space and below
the roof; (c) measuring the temperature of the ground, and (d)
comparing the temperatures measured in steps (a), (b) and (c) and
in response thereto, determining if a flow of the heat exchange
medium should be induced through the first conduit or the second
conduit.
15. A heating and cooling system for a structure having a heated
interior space and an insulated roof over the heated interior
space, comprising: furnace means for heating the interior space;
fan means for inducing a flow or air into said interior space; heat
exchanger means for extracting heat from a heat exchange medium
conducted through the heat exchanger, the heat exchanger means
operatively connected to the fan means; first conduit means for
conducting said heat exchange medium through the heat exchanger
means and over the heated interior space, said first conduit means
at least partially located above the heated interior space and
below the insulated roof; controller means for initiation of a flow
of the heat exchange medium through the first conduit means, and
for controlling operation of the furnace means, fan means and heat
exchanger means.
16. The heating and cooling system according to claim 15 further
comprising a thermostat in the heated interior space and air
temperature sensing means located between said heated interior
space and the insulated roof for measuring the air temperature at
said temperature sensing means, said thermostat and temperature
sensing means configured for communicating with said controller
means.
17. The heating and cooling system according to claim 15 wherein
said first conduit means further comprises a closed loop conduit
extending from said heat exchanger means over said heated interior
space.
18. The heating and cooling system according to claim 17 wherein
said first conduit means includes pump means for inducing a flow of
heat exchange medium through said closed loop conduit.
19. The heating and cooling system according to claim 16 further
including second conduit means for conducting heat exchange medium
through the heat exchanger means, said second conduit means at
least partially located in the ground.
20. The heating and cooling system according to claim 19 including
ground temperature sensing means for measuring the temperature of
the ground and communicating with said controller means, and
wherein said controller means is capable of selecting either the
first conduit means of the second conduit means based on
temperature data received from the thermostat, the air temperature
sensing means and the ground temperature sensing means.
Description
TECHNICAL FIELD
[0001] This invention relates generally to heating and cooling
systems for structures such as homes and buildings, etc. and more
specifically to such structures utilizing a heating and cooling
system that utilize a heat pump in which heat within the structures
is used to support the heat pump, thus recycling energy that
otherwise would escape from the structure.
BACKGROUND OF THE INVENTION
[0002] Heating and cooling systems that utilize a buried ground
coil through which a medium passes for heating by earthen material
are typically called "geothermal systems." Briefly described,
geothermal heating and cooling systems circulate a fluid heating
medium through coils of tubing that are buried in the ground or
immersed in a pond. The earth acts as a source of heat; the fluid
is heated as it is circulated through the coils in the ground and
is then pressurized prior to flowing through a heat exchanger such
as a heat pump, which may be of the liquid-to-air type or
liquid-to-liquid type. The heat derived in the heat pump from the
relatively warmed fluid is used to heat a structure. The fluid,
cooled by passage through the heat exchanger, is directed back to
the buried ground coil where it is again warmed by the heat
retained in the earth.
[0003] There are of course many variations on this basic theme.
Some geothermal systems are of the "closed" type, where the loops
that circulate the heating medium are in a fully close loop that is
buried in the ground. Other systems are "open." In an open loop
system, ground water is pumped through a geothermal heat pump where
heat is drawn off the liquid. The relatively cooled water is then
discharged into a pond. As noted above, a "geothermal" system may
also contemplate immersion of the coils in a pond. In this sense, a
body of water also acts as a heat source that may be utilized to
warm the medium that flows through the coils.
[0004] In addition to geothermal heating and cooling systems,
conventional electric heat pumps are used ubiquitously because all
of these kinds of units help make usage of energy more efficient.
Nonetheless, as energy resources become more scarce, and as demand
for energy increases, there is a substantial need for heating and
cooling systems that use energy more efficiently. As a corollary,
as energy becomes more expensive the demand for energy-efficient
heating and cooling systems increases as a matter of economics: the
less energy that is used, the less the cost of purchasing the
energy.
[0005] There is a significant need therefore for efficient heating
and cooling systems for homes and buildings.
SUMMARY
[0006] The present invention is an improved method and apparatus
for efficiently heating and cooling a structure such as a
residence, commercial building, etc. The system utilizes a closed
loop system similar to a closed loop geothermal heating system but
locates the coils in the system to the interior of the structure in
a location where the coils are able to be heated by relatively warm
air that is used to heat the building. The structure may utilize an
optional heating system such as a geothermal heating system,
furnace or a conventional electric heat pump. The closed loop
system that is located in the interior of the structure is
configured to capture heat from the interior of the structure and
use that heat to warm the heating medium in the coils.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a schematic sectional view of a structure having a
heating and cooling system according to the present invention.
[0008] FIG. 2 is a schematic view showing the components of the
heating and cooling system according to the present invention in
isolation.
[0009] FIG. 3 is a plan view of an alternative arrangement of the
interior coils used in accordance with the present invention.
[0010] FIG. 4 is an isolated schematic view of the control system
according to the present invention.
DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS
[0011] With reference to FIG. 1, the heating and cooling system 10
according to the present invention is illustrated in a first
embodiment in a structure 12 such as a typical residential
building. It will be understood that structure 12 is shown as a
residential type of building only to illustrate the invention,
which could be used with any kind of structure, including multiple
story structures. Heating and cooling system 10 comprises several
different components, each of which is described in detail below,
including a furnace 14, a geothermal heat pump 16, an optional
ground source loop 18, a structure source loop 20 and a controller
22 that is under the control of a microprocessor and which is
functional to control operation of the entire system. The structure
12 illustrated in FIG. 1 is typical of a residence that includes a
below-ground-level basement 24--the furnace 14, geothermal heat
pump 16 and controller 22 are all located in the basement. It will
be appreciated that the heating and cooling system 10 may be
incorporated into any kind of structure, including commercial
buildings and the like, and of course it is not necessary that the
building include a basement.
[0012] Individual components of heating and cooling system 10 will
be described beginning with furnace 14. The furnace used with the
present invention may be any kind, including conventional forced
air gas-fired or electric furnaces, and other "furnace" types
including radiant floor heating. The purpose of furnace 14 is to
provide heat and cooling to structure 12. Accordingly, it will be
appreciated that the term "furnace" is used generically herein to
describe any heat source for heating and cooling structure 12.
Nonetheless, the furnace 14 illustrated herein is conventional and
is under the control of a thermostat 26 that regulates operation of
the furnace, and which typically is located in a convenient place
in structure 12. Different thermostat configurations may be used,
for example, thermostats that rely upon various zones. The furnace
illustrated herein includes conventional ducting 28 and a fan shown
schematically at 29 that delivers heated (and cooled) air to the
interior of the structure, and as shown in FIG. 2, conventional
return air ducting. It will be appreciated based on the description
below that the fan 28 operates not only to deliver air heated by
the furnace 14 to structure 12, but also to deliver air heated
and/or cooled by operation of geothermal heat pump 16 to the
structure. Therefore, if the "furnace" used in structure 12 is of
the type that normally would not include a fan, such as a radiant
floor heating system, then fan 29 and ducting 28 will be connected
to the heat pump 16.
[0013] Geothermal heat pump 16 also is a conventional unit that
essentially functions as a medium-to-air heat exchanger where heat
carried into the heat pump from one of the source loops (i.e.,
either the structure source loop 20 or the ground source loop 18)
is drawn off in the heat pump and transferred into the forced air
conduit system of furnace 14 so that the heat may be used to warm
structure 12. The geothermal heat pump 16 may be of any known type,
such as an air-to-water heat pump, or a water-to-water type. With
reference to FIG. 2, the geothermal heat pump 16 comprises a
conventional heat pump unit 30 (which as noted may be of any type)
that is connected through controller 22 to both source loops--that
is, structure source loop 20 and ground source loop 18.
[0014] As noted, ground source loop 18 should be considered
optional in the present invention. Generally described, a ground
source loop system relies upon the relative temperature of the
ground to heat or cool a heat exchange fluid flowing through coils
that are buried in the ground. As relatively cool fluid flows from
the cool side of the system and is circulated through the coils,
the fluid is either warmed or cooled by the ground. The relatively
warmed or cooled fluid is drawn off or extracted in a heat pump,
which functions as a heat exchanger, to supply warm air or cool
air, as the case may be, to structure.
[0015] The ground source loop 18 shown in the figures comprises a
length of conduit or tubing defined as ground loop coils 32 which
are buried in the ground at an appropriate depth. The ground loop
coils 32 could just as well be submersed in a pond. A horizontal
ground loop system is illustrated in FIG. 1, but it will be
appreciated that the ground source loop 18 may utilize many other
different configurations such as pond loops, vertical ground loops,
open loops, etc. The ground loop coils 32 illustrated in FIG. 2
show a typical winter configuration having a cool side 34 and a
warm side 36. Relatively cool exchange fluid exiting heat pump unit
30 enters the ground loop coils 32 in cool side 34. As the fluid
flows through tubing 38, the exchange fluid is warmed by the heat
of the earth, resulting in the "warm side" 36 being at the
"downstream" end of the tubing. Heat exchange fluid flowing from
the warm side 36 enters the heat pump unit 30 where the heat is
drawn off for heating structure 12. The tubing 38 used to define
ground loop coils 32 is preferably conventional, and the length of
tubing used in the ground loop is variable depending upon the
particular installation. Various heat exchange fluids may be
circulated through the loops. Briefly and generally described,
geothermal heating systems such as ground source loop 18 utilize
the heat storage capacity of the earth or ground water to heat
fluid flowing through the ground loop coils.
[0016] The structure source loop 20 according to the present
invention is similar to the ground source loop 18 but is located in
a different location and derives heat from different sources.
Structure source loop 20 is connected to geothermal heat pump 16
through controller 22 and, assuming that structure 12 includes a
ground source loop 18, defines a second heat exchange system used
in structure 12. The structure source loop 20 illustrated in FIG. 2
shows a typical winter configuration in which the loops define a
cool side 42 and a warm side 44. As described above, relatively
cool exchange fluid enters the tubing of structure source loop 20
from heat pump unit 30 in the cool side 42. The heat pump unit 30
is thus in discharge and receiving communication with the conduits
of the structure source loop. The fluid medium is warmed as it
circulates so that when the fluid returns to the heat pump unit it
is returning at warm side 44. Structure source loop 20 is
necessarily a closed loop system, whereas when a ground loop source
18 is used, it may be an open loop system. As with ground source
loop 18, the tubing 46 used in structure source loop 20 is
conventional and the fluid that circulates through the tubing may
be of various types of refrigerant fluids.
[0017] Returning to FIG. 1, it may be seen that the tubing 46 of
structure source loop 20 is connected through controller 22 to heat
pump 16 and is preferably plumbed through the walls of structure 12
or through a chase. The conduit or tubing runs upwardly through the
walls and is installed in a series of loops above the heated space
48 (sometimes referred to herein as "winter-heated space") in the
interior of structure 12. As air in the interior of structure 12 is
heated, whether by furnace 14 or otherwise, the warm air rises
toward the ceiling 50. By positioning the tubing of structure
source loop 20 above the winter-heated space 48, the fluid
circulating through the tubing 46 is heated by the warm air. This
heat is then recovered from the fluid in geothermal heat pump 16 in
the same manner that heat from ground source loop 18 is recovered
in the heat pump.
[0018] It will be appreciated that there are numerous equivalent
manners in which the tubing 46 of structure source loop 20 may be
installed above the winter-heated space 48, and further that the
length of tubing used in any particular installation, including the
length of tubing installed above the heated space, will vary.
Preferably, the length of tubing installed above the heated space
provides substantial surface area for exchange of heat from the
warm air in the structure to the heat exchange fluid flowing
through the conduit. With reference to FIGS. 1 and 3, the tubing 46
is shown in a first illustrated embodiment installed between roof
structures such as trusses 52 and above the finished ceiling layer
54. A layer of insulation 56 is installed above the tubing 46 in
order to minimize exposure of the tubing to any temperature
fluctuations from the exterior of the structure. Alternately,
tubing 46 may be installed so that the loops run in a direction
that is generally transverse to the trusses. The finished ceiling
layer 54 may include vents and other architectural features that
allow free circulation of heated air from the structure to the
tubing 46. Moreover, the entire structure source loop 20 may be
installed so that the tubing itself is in the interior of the
structure in the winter-heated space 48. In this respect, it will
be understood that the structure source loop 20 is installed above
the winter-heated space, but below the roof 51, and with a layer of
insulation 56 interposed between the tubing and the roof.
[0019] Regardless of the particular manner in which the coils of
structure source loop 20 are installed, insulation is used between
the tubing and the roof to ensure that the loop 20 is exposed to
the interior of the structure but is insulated from cold air above
the insulation and the exterior of the structure.
[0020] With reference now to FIGS. 2 and 4, controller 22 is shown
schematically to comprise a flow control system with valves 58 and
60 that are multiport valves connected to both the ground source
loop 18 and structure source loop 20. Valves 58 and 60 are
configured for selecting either ground source loop 18 or structure
source loop 20 and directing the fluid flow from the selected loop
to geothermal heat pump 16. As shown in FIG. 4, controller 22
includes two automated multiport valves 58 and 60, each of which
are preferably electrically actuated under the control of a
microprocessor 62. Microprocessor 62 communicates with thermostat
26 through data line 64 and to the valves 58 and 60. As noted,
controller 22 is configured for selecting either ground source loop
18 or structure source loop 20. When structure source loop 18 is
selected, valves 58 and 60 are operated under the control of
microprocessor 62 to define a flow path from warm side 44 through
valve 58 and through warm side tubing 66 to geothermal heat pump
16. Heat is exchanged in heat pump 16 and the cooled fluid is
routed through cool side tubing 68 through valve 60 into cool side
42 of the structure source loop.
[0021] On the other hand, when ground source loop 18 is selected,
microprocessor 62 operates valves 58 and 60 to define a flow path
from warm side 36 through valve 58 and through warm side tubing 66
to heat pump 16. The cooled fluid is routed through cool side
tubing 68 through valve 60 into cool side 34 of the ground source
loop. It will be appreciated by those of ordinary skill in the art
that one or more pumps are required as means to control flow of
fluid through the structure source loop and ground source loop, and
that the pumps are also under the control of microprocessor 62.
Pumps 59 and 61 are shown schematically in FIG. 2 for structure
source loop 20 and ground source loop 18, respectively. For
example, the pump 61 that controls fluid flow through ground source
loop 18 is inactivated when structure source loop 20 is activated,
and so on. Further, multiport valves 58 and 68 may include
additional ports that allow for recirculation of coolant through
the loops bypassing the geothermal heat pump 16.
[0022] Operation of the heating and cooling system 10 will now be
detailed in a first preferred embodiment in which a structure
source loop 20 is used in structure 12, but a ground source loop 18
is not used. It should be understood that the invention described
herein relates primarily to the structure source loop 20. The
structure source loop 20 may be combined with a ground source loop
18 as described, but the ground source loop is optional. Thermostat
26 serves as the primary user interface for control of the system.
When thermostat 26 determines that the temperature of the
winter-heated space 48 is below a predetermined minimum
temperature, or for example when the temperature on the thermostat
is increased, the thermostat queries a ceiling temperature sensor
70 that is located above the winter-heated space 48 and measures
the air temperature at the sensor. In FIG. 1, ceiling temperature
sensor 70 is shown near the apex of the vaulted ceiling. It will be
appreciated that multiple sensors 70 may be used, and their
locations may vary. Temperature data from sensor 70 is communicated
to microprocessor 62 and the ceiling temperature data is compared
to temperature data measured at thermostat 26, which also is
communicated to microprocessor 62. Microprocessor 62 is
preprogrammed with information and instructions for operation of
heating and cooling system 10. If the temperature measured at
sensor 70 is significant enough that heat may be recovered by
operation of structure source loop 20, microprocessor 62 actuates
valves 58 and 60 as described above to select the structure source
loop and fluid flow through the structure source loop is initiated
by microprocessor 62 activating pump 59. Thus, microprocessor 62
will initiate operation of structure source loop 20 is the
difference in the temperature measured at thermostat 26 and
temperature sensor 70 is greater than a predetermined minimum that
is programmed into the microprocessor. Once the structure source
loop is activated and pump 59 is turned on, heat exchange fluid
flows through the conduits. As the exchange fluid in tubing 46
warms as it passes over the winter-heated space and flows back into
geothermal heat pump 16, heat is extracted in the heat pump as
warmed air (geothermal heat pump 16 is in this instance a
medium-to-air exchanger). The geothermal heat pump 16 is operated
in conjunction with furnace 14 to direct the warm air derived from
the exchange fluid flowing through tubing 46 into the winter-heated
space 48 through ducting 28 by operation of fan 29. Depending upon
the difference between the temperature at ceiling temperature
sensor 70 and thermostat 26, operation of the structure source loop
20 may be delayed while furnace 14 is operated by itself to provide
supplemental heat to raise the temperature of the winter-heated
space 48 until the temperature measured at sensor 70 meets a
predetermined level where operation of the structure source loop 20
is determined by microprocessor 62 to be desired. The furnace may
be operated with the furnace fan only, in which case heat drawn off
the warm side of the structure source loop is used to heat
structure 12. In other instances the supplemental heating system in
furnace 14 may be operated simultaneously with geothermal heat pump
16 to heat structure 12. When the temperature at thermostat 26
reaches the predetermined or preset level microprocessor 62
controls and operates furnace 14, geothermal heat pump 16 and
structure source loop 20 to maintain the desired temperature (as
measured at thermostat 26). As the interior temperature of
structure 12 rises, the warm air in the structure rises toward the
ceiling. This heated air warms the fluid circulating through the
tubing of structure source loop 20 so the heat is efficiently
recovered by heat pump 16. This minimizes the amount of
supplemental heat that is required from furnace 14 and thus
minimizes energy consumption.
[0023] It will be appreciated that the structure source loop 20
will be used primarily in the winter months as a means of
recovering heat from the warmed interior of a building. However,
structure source loop 20 may be used for cooling as well. Consider
for example a circumstance where the air temperature outside of
structure 12 is relatively high, as in summer months, and the
temperature at sensor 70 is lower than the temperature that is
entered into thermostat 26. In such instances the structure source
loop may be operated so that air that is at a temperature lower
than that entered into the thermostat is circulated in the
structure. Structure source loop 20 thus defines a method of
recovering heat that is generated in a structure, and re-using that
heat to warm the structure.
[0024] If heating and cooling system 10 includes a ground source
loop 18 and a structure source loop 20, microprocessor 62 is
preprogrammed to select either the ground source loop 18 or the
structure source loop 20 depending upon which loop will provide the
most efficient heat exchange. As shown in FIG. 1, a ground
temperature sensor 72 is placed in the ground and communicates
ground temperature data to microprocessor 62. Generally stated, if
the air temperature at thermostat 26 indicates that either heating
or cooling is necessary, microprocessor 62 queries the temperature
sensors 70 and 72 and compares those temperatures with the
temperature at the thermostat. Assuming the temperature difference
between the thermostat and one of the sensors is sufficient that
the heating and cooling system 10 is operable in an efficient
manner--which is determined by preprogrammed instructions in
microprocessor 62--the microprocessor selects the source loop that
can deliver exchange fluid to the heat pump at a temperature that
is closest to the temperature at the thermostat. Accordingly, the
selected source loop, i.e., either ground source loop 18 or
structure source loop 20, is the one that would take less energy to
change the temperature inside the structure to the desired
temperature. Thus, in this situation microprocessor 62 will always
select the source loop at which the temperature is closes to the
temperature desired at thermostat 26.
[0025] Operation of the ground source loop 18 is identical to
operation of the structure source loop 20 described above. Thus,
when thermostat 26 determines that the temperature of the
winter-heated space is below a predetermined minimum temperature,
or when a specific temperature is entered into the thermostat, the
thermostat queries both ceiling temperature sensor 70 and ground
temperature sensor 72. Temperature data from sensors 70 and 72 is
communicated to microprocessor 62 and the temperature data are
compared to temperature data measured at thermostat 26.
Microprocessor compares temperature data from sensors 70 and 72 and
determines whether heat may be recovered from one of the loops
(i.e., either structure source loop 20 or ground source loop 18),
and if so, which loop will provide the most efficient heat
exchange. In this example, assuming that microprocessor 62 compares
temperature data from sensors 70 and 72 and determines that more
heat may be recovered from ground source loop 18, microprocessor 62
operates valves 58 and 60 to select the ground source loop and
fluid flow through the ground source loop is initiated. Geothermal
heat pump 16 is operated either alone or in conjunction with
furnace 14 to direct warm air into the winter-heated space 48
through ducting 28. As with the structure source loop 20, depending
upon the difference between the temperature at ground temperature
sensor 72 and thermostat 26, operation of the ground source loop 18
may be delayed while furnace 14 is operated by itself to raise the
temperature of the winter-heated space 48 until the temperature
difference between the two points meets a predetermined level where
it operation of the ground source loop 18 is determined to meet
predetermined efficiency criteria programmed in the microprocessor.
And as noted earlier, the furnace may be operated with the furnace
fan only, in which case heat drawn off the warm side of the ground
source loop is used to heat structure 12. In other instances the
heating system in furnace 14 may be operated simultaneously with
geothermal heat pump 16 to heat structure 12.
[0026] When the temperature at thermostat 26 reaches the
predetermined level microprocessor 62 controls and operates furnace
14, geothermal heat pump 16 and a selected loop 18 or 20 to
maintain the desired temperature (as measured at thermostat 26).
Thus, in a structure 12 that includes both a structure source loop
20 and a ground source loop 18, the microprocessor continuously
queries temperature sensors 70 and 72, compares temperature data to
determine which loop would be most efficient, and operates the
heating and cooling system 10 accordingly.
[0027] Typically, a ground source loop 18 is relied upon more in
the summer months with a structure 10 that includes a structure
source loop 20. An example illustrates the foregoing. Assume that
the temperature in the interior of structure 12 is 65.degree. F.
and an occupant sets thermostat 26 to 72.degree. F. Thermostat 26
communicates that data to microprocessor 62. In this example,
assume further that the temperature measured at sensor 70 is
78.degree. F., and that the temperature measured at sensor 72 is
55.degree. F. Microprocessor 62 compares these data from sensors 70
and 72 and because the temperature at sensor 72 is below the
temperature entered into thermostat 26, will not select ground
source loop 18. On the other hand, the temperature at sensor 70 for
structure source loop 20 is greater than the temperature entered
into the thermostat. Accordingly, if the difference between the
temperature at sensor 70 and the temperature entered into
thermostat 26 is greater than a preset minimum difference
programmed into microprocessor 62, the microprocessor will initiate
selection and operation of the structure source loop as described
above. The preset minimum temperature difference programmed into
microprocessor 62 for initiation of one of the heating and cooling
loops is determined by many factors, including the efficiency of
the system, the local climate, etc. and may be varied as necessary
in any particular installation. In a different example, if the
difference between the temperature at the thermostat and the
temperature at sensor 72 exceeds a predetermined minimum, and the
temperature at sensor 72 is greater than the temperature at sensor
70, then the controller will select the ground source loop 18 and
will initiate operation of that loop.
[0028] It will be appreciated that the heating and cooling system
10 operates in a like manner when cooling of the structure is
desired.
[0029] It will further be appreciated that various equivalent
heating and cooling systems may be made by modifying the foregoing
described embodiments. For example, the tubing 46 of structure
source loop 20 may be replaced by a membrane-like sheet having
fluid channels formed therein, where the membrane is installed
between the heated interior space 48 insulation 56. Those of
ordinary skill in the art will understand that other similar
modifications will result in an equivalent apparatus for recovering
heat from the interior of the structure via heat exchange fluid
flowing above the heated interior space.
[0030] Having here described illustrated embodiments of the
invention, it is anticipated that other modifications may be made
thereto within the scope of the invention by those of ordinary
skill in the art. It will thus be appreciated and understood that
the spirit and scope of the invention is not limited to those
embodiments, but extend to the various modifications and
equivalents as defined in the appended claims.
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