U.S. patent application number 13/179288 was filed with the patent office on 2011-11-03 for high-efficiency heat pumps.
This patent application is currently assigned to TRAK INTERNATIONAL, LLC. Invention is credited to Jeffrey H. Maxwell.
Application Number | 20110265502 13/179288 |
Document ID | / |
Family ID | 41382369 |
Filed Date | 2011-11-03 |
United States Patent
Application |
20110265502 |
Kind Code |
A1 |
Maxwell; Jeffrey H. |
November 3, 2011 |
HIGH-EFFICIENCY HEAT PUMPS
Abstract
As discussed herein, a first aspect of the present invention
provides a high-efficiency heat pump that includes a frame, as well
as a first circuit, a first compressor, a condenser heat exchanger,
a first electronic expansion valve, an evaporator heat exchanger,
and a controller. The first circuit, the first compressor, the
condenser heat exchanger, the first electronic expansion valve, and
the evaporator heat exchanger can be supported by the frame. The
first compressor, the condenser heat exchanger, the first
electronic expansion valve, and the evaporator heat exchanger can
be connected to the first circuit. The controller can be in
electronic communication with the first electronic expansion valve,
and the controller can be configured to control operation of the
first electronic expansion valve and/or the second electronic
expansion valve.
Inventors: |
Maxwell; Jeffrey H.;
(Kelowna, CA) |
Assignee: |
TRAK INTERNATIONAL, LLC
St. Paul
MN
|
Family ID: |
41382369 |
Appl. No.: |
13/179288 |
Filed: |
July 8, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12607535 |
Oct 28, 2009 |
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13179288 |
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61108961 |
Oct 28, 2008 |
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Current U.S.
Class: |
62/113 ;
62/324.6; 62/56 |
Current CPC
Class: |
Y02E 10/125 20130101;
Y02B 30/108 20130101; F24D 12/02 20130101; F24S 2025/011 20180501;
F24D 19/1024 20130101; Y02B 30/00 20130101; F24D 19/1009 20130101;
F24T 10/17 20180501; F24D 15/00 20130101; F24D 19/1045 20130101;
F24D 2200/11 20130101; F24H 9/14 20130101; Y10T 29/49826 20150115;
F24H 9/142 20130101; Y02B 30/14 20130101; F24F 5/0003 20130101;
Y02B 30/52 20130101; Y02E 10/10 20130101; F24S 2080/05 20180501;
F24D 3/10 20130101; Y02B 10/40 20130101; F25B 2400/06 20130101;
F24D 2200/20 20130101; F24F 3/08 20130101; Y02B 10/20 20130101;
F24D 2200/22 20130101; F24D 2200/14 20130101; F24D 2200/12
20130101; Y02B 10/70 20130101 |
Class at
Publication: |
62/113 ;
62/324.6; 62/56 |
International
Class: |
F25B 30/00 20060101
F25B030/00 |
Claims
1. A high-efficiency heat pump, comprising: (a) a frame; (b) a
first circuit supported by the frame and configured to circulate a
first refrigerant; (c) a first compressor supported by the frame
and connected to the first circuit, the first compressor being
configured to (i) receive the first refrigerant from the first
circuit, (ii) increase pressure of the first refrigerant, and (iii)
provide the higher-pressure first refrigerant back to the first
circuit; (d) a condenser heat exchanger supported by the frame and
connected to the first circuit, the condenser heat exchanger being
configured to (i) receive the higher-pressure first refrigerant
from the first circuit, (ii) transfer energy from the
higher-pressure first refrigerant to a first HVAC fluid passing
through the condenser heat exchanger, and (iii) provide the first
refrigerant back to the first circuit; (e) a first electronic
expansion valve supported by the frame and connected to the first
circuit, the first electronic expansion valve being configured to
(i) receive the first refrigerant from the first circuit, (ii)
decrease pressure of the first refrigerant, and (iii) provide the
lower-pressure first refrigerant back to the first circuit; (f) an
evaporator heat exchanger supported by the frame and connected to
the first circuit, the evaporator heat exchanger being configured
to (i) receive the lower-pressure first refrigerant from the first
circuit, (ii) transfer energy from a second HVAC fluid passing
through the evaporator heat exchanger to the lower-pressure first
refrigerant, and (iii) provide the first refrigerant back to the
first circuit; and (g) a controller in electronic communication
with the first electronic expansion valve, the controller being
configured to control operation of the first electronic expansion
valve.
2. The high-efficiency heat pump of claim 1, further comprising:
(h) a second circuit supported by the frame and configured to
circulate a second refrigerant; (i) a second compressor supported
by the frame and connected to the second circuit; and (j) a second
electronic expansion valve supported by the frame and connected to
the second circuit, wherein the second compressor is configured to
(i) receive the second refrigerant from the second circuit, (ii)
increase pressure of the second refrigerant, and (iii) provide the
higher-pressure second refrigerant back to the second circuit,
wherein the condenser heat exchanger is further configured to (i)
receive the higher-pressure second refrigerant from the second
circuit, (ii) transfer energy from the higher-pressure second
refrigerant to HVAC fluid passing through the condenser heat
exchanger, and (iii) provide the second refrigerant back to the
second circuit, wherein the second electronic expansion valve is
configured to (i) receive the second refrigerant from the second
circuit, (ii) decrease pressure of the second refrigerant, and
(iii) provide the lower-pressure second refrigerant back to the
second circuit, wherein the evaporator heat exchanger is further
configured to (i) receive the lower-pressure second refrigerant
from the second circuit, (ii) transfer energy from HVAC fluid
passing through the evaporator heat exchanger to the lower-pressure
second refrigerant, and (iii) provide the second refrigerant back
to the second circuit, and wherein the controller is in electronic
communication with the first electronic expansion valve and/or the
second electronic expansion valve, the controller being configured
to control operation of the first electronic expansion valve and/or
the second electronic expansion valve.
3. The high-efficiency heat pump of claim 2, wherein the controller
is configured to modulate the first and second compressors.
4-5. (canceled)
6. The high-efficiency heat pump of claim 1, wherein the first
electronic expansion valve is configured to communicate
electronically with an operator and/or a remote controller through
a network.
7. (canceled)
8. The high-efficiency heat pump of claim 1, wherein the first
expansion valve is controllable to (A) simultaneously heat the
first HVAC fluid to a temperature above 100 F and cool the second
HVAC fluid to a temperature below 10 F in a first season and (B)
simultaneously heat the first HVAC fluid to a temperature above 160
F and cool the second HVAC fluid to a temperature below 40 F in a
second season.
9. A method of efficiently heating and/or cooling HVAC fluid,
comprising: (a) providing a high-efficiency heat pump that
includes: (i) a frame, (ii) a first compressor, a condenser heat
exchanger, a first electronic expansion valve, and an evaporator
heat exchanger, each supported by the frame, and (iii) a first
circuit supported by the frame and configured to circulate a first
refrigerant through the first compressor, the condenser heat
exchanger, the first electronic expansion valve, and the evaporator
heat exchanger; (b) circulating a first HVAC fluid through the
condenser heat exchanger or the evaporator heat exchanger; (c)
activating the first compressor to heat the first HVAC fluid if the
first HVAC fluid is circulating through the condenser heat
exchanger or to cool the first HVAC fluid if the first HVAC fluid
is circulating through the evaporator heat exchanger; and (d)
controlling the first electronic expansion valve to control heating
of the first HVAC fluid if the first HVAC fluid is circulating
through the condenser heat exchanger or to control cooling of the
first HVAC fluid if the first HVAC fluid is circulating through the
evaporator heat exchanger.
10. The method of claim 9, further comprising (e) circulating a
second HVAC fluid through whichever of the heat exchangers the
first HVAC fluid is not circulating through, wherein activating the
first compressor simultaneously heats the HVAC fluid in the
condenser heat exchanger to a temperature above 125 F and cools the
HVAC fluid in the evaporator heat exchanger to a temperature below
35 F.
11. The method of claim 10, wherein activating the first compressor
simultaneously heats the HVAC fluid in the condenser heat exchanger
to a temperature above 130 F and cools the HVAC fluid in the
evaporator heat exchanger to a temperature below 30 F.
12. The method of claim 9, wherein the heat pump further includes:
(iv) a second compressor and a second electronic expansion valve,
both supported by the frame, and (v) a second circuit supported by
the frame and configured to circulate a second refrigerant through
the second compressor, the condenser heat exchanger, the second
electronic expansion valve, and the evaporator heat exchanger.
13. The method of claim 12, further comprising activating both the
first compressor and the second compressor to heat the first HVAC
fluid if the first HVAC fluid is circulating through the condenser
heat exchanger or to cool the first HVAC fluid if the first HVAC
fluid is circulating through the evaporator heat exchanger.
14. (canceled)
15. The method of claim 12, wherein the first refrigerant and the
second refrigerant are different refrigerants having different
properties.
16. The method of claim 9, wherein controlling the first electronic
expansion valve comprises remotely controlling the first electronic
expansion valve.
17. The method of claim 16, wherein remotely controlling the first
electronic expansion valve comprises controlling operation of the
first electronic expansion valve based on input from one or more
sensors of an HVAC system that incorporates the heat pump.
18-28. (canceled)
29. A method of achieving a predetermined temperature difference in
an HVAC fluid, comprising: (a) providing an initial heat pump and a
subsequent heat pump; (b) connecting the initial heat pump and the
subsequent heat pump in series; (c) circulating the HVAC fluid
through the initial heat pump to achieve a first temperature
difference in the HVAC fluid; and (d) circulating the HVAC fluid
through the subsequent heat pump to achieve a second temperature
difference, wherein the first and second temperature differences
sum to be approximately equal to the predetermined temperature
difference.
30. The method of claim 29, wherein the initial heat pump and/or
the subsequent heat pump includes a controllable electronic
expansion valve configured to control performance of the initial
heat pump and/or the subsequent heat pump.
31. The method of claim 30, wherein the controllable electronic
expansion valve is remotely controllable.
32. The method of claim 29, wherein the initial heat pump and/or
the subsequent heat pump comprise two or more heat pump units.
33. (canceled)
34. The method of claim 29, wherein the predetermined temperature
difference is a temperature increase of 150 F.
35. (canceled)
36. The method of claim 29, wherein the predetermined temperature
difference is a temperature decrease of 150 F.
37. (canceled)
38. The method of claim 29, further comprising (e) circulating a
first refrigerant through the initial heat pump and circulating a
second refrigerant through the subsequent heat pump, wherein the
first refrigerant and the second refrigerant are different
refrigerants having different properties.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. application Ser.
No. 12/607,535, filed Oct. 28, 2009, which claims priority under 35
U.S.C. .sctn.119(e) to provisional application 61/108,961, filed
Oct. 28, 2008, the entirety of which is hereby incorporated by
reference herein.
BACKGROUND
[0002] HVAC systems involving water-to-water central heat pumps are
becoming more common. In their most basic form, such systems
include a heat pump that warms or cools HVAC fluid circulated
through pipes within a building. A fan blows air from the
conditioned space across warmed or cooled coils connected to the
pipes. The temperature of the air blown from the fan across the
coil (typically done by a fan coil unit) is thus affected by the
temperature-controlled HVAC fluid flowing within the pipes. By
controlling the temperature and flow rate of the HVAC fluid within
the pipes, the location and configuration of the pipes and fan
coil(s), the speed and capacity of the fan coil(s), and the
parameters of various additional equipment that may be incorporated
into the system, the conditioned space can be maintained at
required conditions with relative ease.
[0003] Although heat pump HVAC systems are commonly more efficient
than conventional HVAC systems, they still consume electrical
energy to operate. Differently configured heat pump HVAC systems
vary in energy consumption and efficiency. Most systems do not take
advantage of various sources of "free" energy. Additionally, most
early heat pump HVAC systems were slow to respond to building and
space load changes and were more difficult for users to control
than conventional HVAC systems. When they thus rely upon backup
systems, such as electric duct heaters, they can have relatively
high instantaneous electricity demand and overall higher
electricity consumption. The distributed small compressors create
noise and vibration problems and require continuous HVAC liquid
flow rates to stay operational. The total system power consumption
can become a significant related expense that devalues the energy
and operation cost savings the technology can create.
SUMMARY
[0004] In some embodiments, the present invention provides an
energy efficient HVAC system that optionally includes a
water-to-water heat pump, along with one or more components
configured to take advantage of unused energy sources and/or energy
sinks, thereby significantly reducing the amount of energy that is
potentially required to be added to the system for efficient
operation.
[0005] In some embodiments, the present invention provides a heat
pump including two heat exchangers connected by two or more
refrigeration circuits, with each circuit having an expansion valve
and a compressor that are optionally in electronic communication
with a main controller, thereby permitting relatively precise
remote control of the heat pump.
[0006] In some embodiments, the present invention provides a group
of multi-circuit water-to-water heat pumps connected together in
parallel in a modular fashion, with each circuit of each heat pump
having a remotely controllable expansion valve and/or compressor,
thereby providing a highly flexible and responsive heat pump
system.
[0007] In some embodiments, the present invention provides multiple
individual heat pumps and/or groups of heat pumps connected in
parallel (see previous paragraph) that are connected in series in
order to achieve a relatively large temperature difference, with
each heat pump or heat pump group being configured to operate
within its optimal temperature range in incrementally achieving the
relatively large temperature difference.
[0008] In some embodiments, the present invention provides a method
of operating a multi-circuit heat pump, including (a) receiving
instructions concerning what is needed of the heat pump from a main
controller based on input from sensors located in various places in
the HVAC system and (b) responding to those instructions by
activating (or maintaining activation of) or deactivating (or
maintaining deactivation of) one or more compressors in a selected
sequence and at selected time intervals, provided that such
response is not restricted based on the detection of heat pump or
HVAC system irregularities.
[0009] In some embodiments, the present invention provides a method
of monitoring for irregularities in heat pumps that are either
activated or pending activation to prevent premature wear or
failure of heat pump components and/or to improve energy efficiency
in the heat pumps.
[0010] In some embodiments, the present invention provides an
energy transfer component that includes an outer tube made of
thermally conductive material and a concentric inner tube that can
be made of thermally insulative material, with (a) HVAC fluid
flowing turbulently through the channel between the inner and outer
tubes, optionally guided by a spiraling barrier, such that heat
transfer occurs between the turbulently flowing HVAC liquid and the
surrounding earth, water, or combination thereof and (b) HVAC fluid
flowing laminarly inside the inner tube, thereby minimizing heat
transfer between the HVAC fluid flowing between the inner and outer
tubes and the HVAC fluid flowing inside the inner tube.
[0011] In some embodiments, the present invention provides system
components assembled as a modular box, which enables fast and easy
installation and replacement of the modular box, thereby permitting
assembly and repair of the distribution equipment in a more
suitable setting, such as a machine shop.
[0012] In some embodiments, the present invention provides a
distribution system that optionally accommodates potable water as
the HVAC fluid by regularly circulating the potable water through a
single coil in a fan box, that optionally includes a controller,
that is in electronic communication with a main controller and/or
one or more other components of the HVAC system.
[0013] Details of several aspects and embodiments of the present
invention are provided herein.
[0014] Related technology is disclosed in commonly owned U.S.
patent application Ser. No. 12/607,930 (filed on Oct. 28, 2009 and
titled CONTROLS FOR HIGH-EFFICIENCY HEAT PUMPS); Ser. No.
12/607,760 (filed on Oct. 28, 2009 and titled METHODS AND EQUIPMENT
FOR GEOTHERMALLY EXCHANGING ENERGY); Ser. No. 12/607,679 (filed on
Oct. 28, 2009 and titled METHODS AND EQUIPMENT FOR HEATING AND
COOLING BUILDING ZONES). Each of the applications noted in this
paragraph are hereby incorporated by reference herein in their
entirety.
BRIEF DESCRIPTION OF FIGURES
[0015] The following drawings are illustrative of particular
embodiments of the present invention and therefore do not limit the
scope of the invention. The drawings are not to scale (unless so
stated) and are intended for use in conjunction with the
explanations in the following detailed description. Embodiments of
the present invention will hereinafter be described in conjunction
with the appended drawings, wherein like numerals denote like
elements.
[0016] FIG. 1A is a schematic diagram of a first illustrative HVAC
system according to some embodiments of the present invention.
[0017] FIG. 1B is a schematic diagram of a second illustrative HVAC
system according to some embodiments of the present invention.
[0018] FIG. 2 is a schematic diagram of an illustrative
dual-circuit heat pump according to some embodiments of the present
invention.
[0019] FIG. 3A is a flow diagram of an illustrative method for
operation of a heat pump according to some embodiments of the
present invention.
[0020] FIG. 3B is a flow diagram of an illustrative method for
protecting against damage to the heat pump stemming from heat pump
irregularities according to some embodiments of the present
invention.
[0021] FIG. 4 is a flow diagram of an illustrative method for
assembling a heat pump according to some embodiments of the present
invention.
[0022] FIG. 5A is a schematic side view of an illustrative
flow-through heat transfer component according to some embodiments
of the present invention.
[0023] FIG. 5B is a schematic end view of the flow-through heat
transfer component of FIG. 5A.
[0024] FIG. 6 is a schematic side view of an illustrative ground
energy transfer component according to some embodiments of the
present invention.
[0025] FIG. 7 is a schematic view of a distribution box with a
control system module according to some embodiments of the present
invention.
[0026] FIG. 8 is a schematic view of a portion of an HVAC system,
including a single coil within a fan box, according to some
embodiments of the present invention.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0027] The following detailed description is exemplary in nature
and is not intended to limit the scope, applicability, or
configuration of the invention in any way. Rather, the following
description provides practical illustrations for implementing
exemplary embodiments of the present invention. Examples of
constructions, materials, dimensions, and manufacturing processes
are provided for selected elements, and all other elements employ
that which is known to those of skill in the field of the
invention. Those skilled in the art will recognize that many of the
examples provided have suitable alternatives that can be
utilized.
[0028] FIG. 1A shows an illustrative HVAC system for heating and/or
cooling two zones 2, 4 within the conditioned space 6 of a
building. The illustrative HVAC system includes a heat pump 8,
several energy transfer components 10, 12, 14, 16, 18, 20, 22, 24,
and distribution boxes 26, 28 (e.g., with control system modules).
The illustrative HVAC system also includes a network of pipes and
valves for distributing hot and/or cold HVAC fluid to the various
components of the system. In many embodiments, the HVAC fluid can
be water (e.g., treated water), an antifreeze solution (e.g.,
glycol mixed with water), or similar fluids. In some embodiments,
the HVAC fluid can be domestic potable water. Individual components
of the system are discussed in greater detail elsewhere herein.
[0029] It should be emphasized that the HVAC system of FIG. 1A is
only illustrative. Some buildings include only one zone. Many
buildings include more than one zone. Many embodiments of the
present invention can be incorporated into large buildings with
many zones and/or into groups of buildings with many zones having
different embodiments complementing the energy balance. HVAC
systems can include any suitable combination of energy transfer
components, heat pumps, distribution components, and/or
piping/valve distribution systems, based on a variety of design
factors. As is discussed in greater detail elsewhere herein, an
HVAC system can include suitable energy transfer component(s) with
or without a heat pump, with or without distribution component(s),
and with or without sections of the illustrated piping/valve
distribution system. Similarly, an HVAC system can include one or
more suitable heat pumps with or without energy transfer
component(s), with or without distribution component(s), and with
or without the illustrated piping/valve distribution system.
Likewise, an HVAC system can include one or more distribution
components with or without energy transfer component(s), with or
without a heat pump, and with or without the illustrated
piping/valve distribution system. As is discussed elsewhere herein,
aspects of the illustrated piping/valve distribution system can be
implemented into a variety of HVAC systems. Many embodiments
include components other than those shown for taking advantage of
sources of "free" energy. Many embodiments include components other
than those shown for using transferred and free energy, such as
snowmelt, radiant heating, domestic hot water, swimming pools, hot
tubs, and so on.
[0030] The illustrative HVAC system of FIG. 1A includes a heat pump
8. Shown are four stages of the heat transfer cycle: a compressor
36, a condenser heat exchanger .sub.34 rejecting energy, an
expansion valve 32, and an evaporator heat exchanger 38 collecting
energy. Heat pump refrigerant (e.g., R22, R134a, R407C, etc.) can
cycle through the components of the heat pump 8 to reject and
absorb heat from the sink and source HVAC fluids connected to the
HVAC fluid side of the condenser and evaporator heat exchangers 34,
38. The heat pump refrigerant can circulate and migrate through the
heat pump heat transfer cycle. The cycle can first be activated by
starting a compressor 36. The work of the compressor 36 can
compress any residual refrigerant liquid or returning vapor (gas)
to a gas of higher pressure and temperature and thus motivate the
refrigerant through the cycle. The high pressure and high
temperature refrigerant can then enter the condenser heat exchanger
34, where the HVAC fluid can cause the refrigerant to condense from
gas to liquid as it rejects sensible and latent heat energy to the
comparatively cooler hot HVAC fluid. The refrigerant can then enter
the expansion valve 32, where the passing refrigerant can be
regulated to only an amount which will completely vaporize in the
spatial volume of the evaporator heat exchanger 38. The suddenly
reduced pressure and increased volume in the evaporator heat
exchanger 38 can cause the liquid refrigerant to flash to gas and
during its change of phase state to absorb its latent heat energy
from the comparatively warmer cold HVAC fluid. The warmed low
pressure refrigerant gas can then return to the compressor 36.
Changes in the phase state of the heat pump refrigerant caused by
pressure and volume changes, combined with temperature changes at
the condenser heat exchanger 34 and the evaporator heat exchanger
38, can cause heat energy to be "pumped" from the connected cold
HVAC fluid to the hot HVAC fluid.
[0031] This energy transfer can simultaneously (a) absorb heat
energy into the heat pump refrigerant changing from liquid to gas
at the evaporator heat exchanger 38, thereby chilling the HVAC
fluid at the evaporator heat exchanger 38, and (b) reject heat from
the heat pump refrigerant by temperature difference at the
condenser heat exchanger 34, thereby heating the HVAC fluid at the
condenser heat exchanger 34. In this way, cooling some HVAC fluid
can be the free by-product of heating other HVAC fluid, and vice
versa, from the same compressor work.
[0032] In heating the conditioned space 6, HVAC fluid can exit the
heat pump 8 through heating loop 40 after passing through the
condenser heat exchanger 34 and can then enter the conditioned
space 6. In cooling the conditioned space 6, HVAC fluid can exit
the heat pump 8 through cooling loop 42 after passing through the
evaporator heat exchanger 38.
[0033] In some embodiments, components of the heat pump 8 can be
selected and/or configured according to particular applications. In
many embodiments, the heat pump 8 can have two or more refrigerant
circuits. FIG. 2 shows an illustrative dual-circuit heat pump 140.
The heat pump 140 includes an evaporator heat exchanger 142 and a
condenser heat exchanger 144. The evaporator heat exchanger 142 can
interact with a chilled HVAC fluid loop 152 and the condenser heat
exchanger 144 can interact with a hot HVAC fluid loop 154. In this
way, the dual-circuit heat pump 140 can provide a similar interface
to HVAC systems as do conventional single-circuit heat pumps. In
many embodiments, dual-circuit heat pumps can enable paired
compressors within the heat pump frame to have separate isolated
heat pump refrigerant circuits (avoiding equalization lines),
providing staging and better control of the refrigerant circuit and
conditioning of the HVAC fluid.
[0034] Inside the heat pump 140, two separate circuits (circuit A
and circuit B in FIG. 2) can channel heat pump refrigerant through
the condenser heat exchanger 144 and the evaporator heat exchanger
142. Circuit A can have a compressor 146A and an expansion valve
148A, and circuit B can have a compressor 146B and an expansion
valve 148B. The heat pump refrigerant and its properties in Circuit
A may be different than the heat pump refrigerant and its
properties in Circuit B. At any given time, compressors 146A, 146B
can both be operational, one of the compressors 146A or 146B can be
operational, or neither compressor 146A nor 146B can be
operational. In this way, the heat pump 140 can operate at 100%
capacity, 50% capacity, or 0% capacity. In this way, the heat pump
can be at peak efficiency when at 100% capacity and when at 50%
capacity. In some embodiments, one or both of the compressors 146A
and 146B can be modulated to provide for greater flexibility in
operating capacity percentage. For example, one or both of the
compressors 146A or 146B can be separately connected to a variable
frequency drive; or one or the other of the compressors 146A, 146B
can compress an alternate refrigerant of different properties, or
one of the compressors 146A, 146B can experience its refrigerant in
a different state as caused by a different tuning of the expansion
valve 148A, 148B. Some heat pumps made and/or used according to the
present invention provide significant enhancements in energy
efficient heating and cooling.
[0035] In many embodiments, the evaporator heat exchanger 142
and/or the condenser heat exchanger 144 are plate-and-frame heat
exchangers. Heat pump refrigerant and HVAC fluid can be channeled
through alternating gaps between the plates. The plates can be made
of thermally conductive material in order to facilitate heat
transfer between the heat pump refrigerant and the HVAC fluid. Heat
transfer can occur according to the design of the heat exchangers
142, 144 and the HVAC system when the heat pump refrigerant and the
HVAC fluid are both flowing through the respective gaps between the
plates. In many embodiments, such as that of FIG. 2, the heat pump
refrigerant and the HVAC fluid flow through the heat exchangers
142, 144 in opposite directions.
[0036] For dual-circuit heat pumps, the heat pump refrigerant from
one circuit can alternate with the heat pump refrigerant from the
other circuit when flowing through the heat exchanger (evaporator
142 or condenser 144). In many embodiments, the heat exchangers can
be of the brazed plate type, in which case the heat transfer fluids
would flow through gaps between sealed plates. The respective
fluids in the heat exchanger gaps would alternate between (a) heat
pump refrigerant from circuit A, (b) HVAC fluid, (c) heat pump
refrigerant from circuit B, (d) HVAC fluid, (e) heat pump
refrigerant from circuit A, and so on. If both of the compressors
146A, 146B were operational, both gaps neighboring the HVAC fluid
would have flowing heat pump refrigerant, meaning that the designed
heat transfer could occur across each plate. If only one of the
compressors 146A, 146B were operational, only one of the gaps
neighboring the HVAC fluid would have flowing heat pump
refrigerant, meaning that the designed heat transfer could occur
across only half of the plates. If neither of the compressors 146A,
146B were operational, neither of the gaps neighboring the HVAC
fluid would have flowing heat pump refrigerant, meaning that the
designed heat transfer could not occur across any of the plates. By
making operational both, either, or neither of the compressors
146A, 146B, the heat pump can operate at 100%, 50%, or 0%
capacity.
[0037] In some embodiments, the absorption of heat from the HVAC
fluid in the evaporator heat exchanger 142 in one or both of the
heat pump circuits can be controlled via the expansion valves 148A,
148B. In many embodiments, the expansion valves 148A, 148B can be
electronic expansion valves, which can control the superheat from
the evaporator heat exchanger 142 across a broad range of valve
percentages (e.g., from 0% to 100%). Many electronic expansion
valves can react faster and more precisely to changing conditions
in the evaporator heat exchanger 142 than a conventional expansion
valve. Some electronic expansion valves can be configured to
communicate electronically with an operator and/or a controller
through a network (e.g., the Internet). In this way, the electronic
expansion valves can be monitored and adjusted remotely. Often, the
precise control of electronic expansion valves' superheat setting
provides significant savings on operational costs. The high range
of valve control and internal programming can enable continuous
operation over a wider range of conditions from ice making to hot
water heating on the same common refrigerant charge.
[0038] The performance of the dual-circuit heat pump 140 can be
impacted by a variety of factors. As noted above, in some
embodiments, the number of compressors 146A, 146B that are
operational (along with, in some embodiments, modulation of one or
both of the compressors 146A, 146B) can impact the performance of
the heat pump 140. As also noted above, the pressure of the heat
pump refrigerant in one or both of the circuits, as controlled via
the expansion valves 148A, 148B, can impact the performance of the
heat pump 140. In some embodiments, the selection of the heat pump
refrigerant can impact the performance of the heat pump 140.
Different heat pump refrigerants change states at different
temperatures and pressures. The overall efficiency of the heat pump
140 can be affected by the characteristics of the refrigerant,
including the energy absorbed or given off during a change of
state. Thus, the selection of a heat pump refrigerant can have a
significant impact on, e.g., the temperature difference across the
heat pump 140 and the work input to motivate the temperature
difference. In some embodiments, the volume of heat pump
refrigerant added to either or both of the circuits can impact the
performance of the heat pump 140. In some embodiments, the volume
of oil in the heat pump refrigerant can impact performance of the
heat pump 140. One or more of these and similar factors can be
controlled to provide optimal heat pump performance, depending on
the circumstances of the particular application. In some
embodiments, the dual-circuit heat pump can reduce the number of
mechanical connections and fittings for the HVAC fluids, thereby
reducing flow restrictions while at the same time increasing
performance. [39] In many embodiments, the heat pump 140 is
designed and/or configured to produce repeatable temperature
differences across the respective heat exchangers 142, 144. In some
instances, flow properties of the HVAC fluid in the chilled HVAC
fluid loop 152 and/or the hot HVAC fluid loop 154 can be adjusted
with control valves 156, 157, 158, 159 to achieve temperature
differences across the heat exchangers 142, 144 that differ from
those that would have been achieved in absence of the adjustment
with the control valves 156, 157, 158, 159. In some embodiments, a
percentage of the HVAC fluid can bypass a heat exchanger by means
of one or more bypass valves.
[0039] In some embodiments, multiple heat pumps 140 are made in
modular fashion, such that each heat pump 140 is a self-contained
unit with clearly defined interfaces to other HVAC system
components, including other heat pumps. Such a setup can provide a
significant degree of flexibility in operating capacity percentage.
The number of heat pumps (and specifically the number of
compressors) is directly related to the number of operating
capacity levels. The number of operating capacity levels is equal
to the number of compressors plus one (accounting for 0% operating
capacity). For example, with five dual-circuit heat pumps connected
in parallel, there are eleven operating capacity levels. Assuming
that all five heat pumps have similar configurations, the heat
pumps collectively can operate at 0% (none of the compressors
operational), 10% (one of the ten compressors operational), 20%
(two of the ten compressors operational), and so on. The HVAC fluid
flow can have equivalent capacity levels of reduced pumping energy
with each refrigerant circuit still operating at optimum capacity
and efficiency. In this way, the heat pumps collectively can
provide what the HVAC system demands in a more precisely tailored
fashion, thereby significantly improving energy efficiency.
[0040] As discussed herein, a first aspect of the present invention
provides a high-efficiency heat pump that includes a frame, as well
as a first circuit, a first compressor, a condenser heat exchanger,
a first electronic expansion valve, an evaporator heat exchanger,
and a controller. The first circuit, the first compressor, the
condenser heat exchanger, the first electronic expansion valve, and
the evaporator heat exchanger can be supported by the frame. The
first compressor, the condenser heat exchanger, the first
electronic expansion valve, and the evaporator heat exchanger can
be connected to the first circuit.
[0041] In the first aspect, the first circuit can be configured to
circulate a first refrigerant. The first compressor can be
configured to (i) receive the first refrigerant from the first
circuit, (ii) increase pressure of the first refrigerant, and (iii)
provide the higher-pressure first refrigerant back to the first
circuit. The condenser heat exchanger can be configured to (i)
receive the higher-pressure first refrigerant from the first
circuit, (ii) transfer energy from the higher-pressure first
refrigerant to a first HVAC fluid passing through the condenser
heat exchanger, and (iii) provide the first refrigerant back to the
first circuit. The first electronic expansion valve can be
configured to (i) receive the first refrigerant from the first
circuit, (ii) decrease pressure of the first refrigerant, and (iii)
provide the lower-pressure first refrigerant back to the first
circuit. The evaporator heat exchanger can be configured to (i)
receive the lower-pressure first refrigerant from the first
circuit, (ii) transfer energy from a second HVAC fluid passing
through the evaporator heat exchanger to the lower-pressure first
refrigerant, and (iii) provide the first refrigerant back to the
first circuit.
[0042] In the first aspect, the heat pump may include a second
circuit, a second compressor, and a second electronic expansion
valve, each supported by the frame. The second circuit can be
configured to circulate a second refrigerant. The second compressor
and the second electronic expansion valve can be connected to the
second circuit. The second compressor can be configured to (i)
receive the second refrigerant from the second circuit, (ii)
increase pressure of the second refrigerant, and (iii) provide the
higher-pressure second refrigerant back to the second circuit. The
condenser heat exchanger can be further configured to (i) receive
the higher-pressure second refrigerant from the second circuit,
(ii) transfer energy from the higher-pressure second refrigerant to
HVAC fluid passing through the condenser heat exchanger, and (iii)
provide the second refrigerant back to the second circuit. The
second electronic expansion valve can be configured to (i) receive
the second refrigerant from the second circuit, (ii) decrease
pressure of the second refrigerant, and (iii) provide the
lower-pressure second refrigerant back to the second circuit. The
evaporator heat exchanger is further configured to (i) receive the
lower-pressure second refrigerant from the second circuit, (ii)
transfer energy from HVAC fluid passing through the evaporator heat
exchanger to the lower-pressure second refrigerant, and (iii)
provide the second refrigerant back to the second circuit.
[0043] In the first aspect, the controller can be in electronic
communication with the first electronic expansion valve and/or the
second electronic expansion valve. The controller can be configured
to control operation of the first electronic expansion valve and/or
the second electronic expansion valve.
[0044] In the first aspect, the high-efficiency heat pump may
include one or more of the following features. The controller may
be configured to modulate the first and second compressors. At
least one of the condenser heat exchanger and the evaporator heat
exchanger can be a plate-and-frame heat exchanger with gaps between
plates. In some such embodiments, the first and second circuits can
be connected to the plate-and-frame heat exchanger so as to channel
the first refrigerant, HVAC fluid, the second refrigerant, and HVAC
fluid, respectively, through alternating gaps. The first
refrigerant and the second refrigerant can be different
refrigerants having different properties. The first electronic
expansion valve can be configured to communicate electronically
with an operator and/or a remote controller through a network. The
controller can be configured to receive input from one or more
sensors of an HVAC system that incorporates the heat pump. In some
such embodiments, the controller can be configured to control
operation of the first electronic expansion valve based on that
input. The first expansion valve can be controllable to (a)
simultaneously heat the first HVAC fluid to a temperature above 100
F and cool the second HVAC fluid to a temperature below 10 F in a
first season and (b) simultaneously heat the first HVAC fluid to a
temperature above 160 F and cool the second HVAC fluid to a
temperature below 40 F in a second season. In some embodiments, the
heat pump can further include a third compressor and a third
electronic expansion valve, both supported by the frame, as well as
a third circuit supported by the frame and configured to circulate
a third refrigerant through the third compressor, the condenser
heat exchanger, the second electronic expansion valve, and the
evaporator heat exchanger.
[0045] As discussed herein, a second aspect of the present
invention provides a method of efficiently heating and/or cooling
HVAC fluid. The method can include providing a high-efficiency heat
pump, such as the heat pump discussed in connection with the first
aspect or other heat pumps discussed herein. The method can include
circulating a first HVAC fluid through the condenser heat exchanger
or the evaporator heat exchanger. The method can include activating
the first compressor to heat the first HVAC fluid if the first HVAC
fluid is circulating through the condenser heat exchanger or to
cool the first HVAC fluid if the first HVAC fluid is circulating
through the evaporator heat exchanger. The method can include
controlling the first electronic expansion valve to control heating
of the first HVAC fluid if the first HVAC fluid is circulating
through the condenser heat exchanger or to control cooling of the
first HVAC fluid if the first HVAC fluid is circulating through the
evaporator heat exchanger.
[0046] In the second aspect, the method of efficiently heating
and/or cooling HVAC fluid may include one or more of the following
features. The method may include circulating a second HVAC fluid
through whichever of the heat exchangers the first HVAC fluid is
not circulating through. In some such embodiments, activating the
first compressor simultaneously heats the HVAC fluid in the
condenser heat exchanger to a temperature above 125 F and cools the
HVAC fluid in the evaporator heat exchanger to a temperature below
35 F. In some such embodiments, activating the first compressor
simultaneously heats the HVAC fluid in the condenser heat exchanger
to a temperature above 130 F and cools the HVAC fluid in the
evaporator heat exchanger to a temperature below 30 F. In
embodiments having a dual-circuit heat pump, the method can include
activating both the first compressor and the second compressor to
heat the first HVAC fluid if the first HVAC fluid is circulating
through the condenser heat exchanger or to cool the first HVAC
fluid if the first HVAC fluid is circulating through the evaporator
heat exchanger. In some embodiments, controlling the first
electronic expansion valve comprises remotely controlling the first
electronic expansion valve. In some such embodiments, remotely
controlling the first electronic expansion valve comprises
controlling operation of the first electronic expansion valve based
on input from one or more sensors of an HVAC system that
incorporates the heat pump.
[0047] As discussed herein, a third aspect of the present invention
provides a method of efficiently heating and/or cooling HVAC fluid.
The method can include providing at least two heat pump units, such
as those discussed in connection with the first aspect or other
heat pumps discussed herein. The method can include connecting the
heat pump units in parallel to create a heat pump. The method can
include circulating a first HVAC fluid through the condenser heat
exchanger or the evaporator heat exchanger of at least one of the
heat pump units. The method can include activating the first
compressor of at least one of the heat pump units to heat the first
HVAC fluid if the first HVAC fluid is circulating through the
condenser heat exchanger(s) or to cool the first HVAC fluid if the
first HVAC fluid is circulating through the evaporator heat
exchanger(s). The method can include controlling the corresponding
first electronic expansion valve(s) to control heating of the first
HVAC fluid if the first HVAC fluid is circulating through the
condenser heat exchanger(s) or to control cooling of the first HVAC
fluid if the first HVAC fluid is circulating through the evaporator
heat exchanger(s).
[0048] In the third aspect, the method of efficiently heating
and/or cooling HVAC fluid may include one or more of the following
features. The method can include circulating a second HVAC fluid
through the whichever of the heat exchangers of the at least one
heat pump unit the first HVAC fluid is not circulating through. In
some such embodiments, activating the first compressor of the at
least one heat pump unit simultaneously heats the HVAC fluid in the
condenser heat exchanger(s) to a temperature above 125 F and cools
the HVAC fluid in the evaporator heat exchanger(s) to a temperature
below 35 F. In some such embodiments, activating the first
compressor of the at least one heat pump unit simultaneously heats
the HVAC fluid in the condenser heat exchanger(s) to a temperature
above 130 F and cools the HVAC fluid in the evaporator heat
exchanger(s) to a temperature below 30 F. The method can include
activating first compressors of multiple heat pump units. In some
embodiments, circulating the first HVAC fluid through the condenser
heat exchanger or the evaporator heat exchanger of at least one of
the heat pump units comprises circulating the first HVAC fluid
through the condenser heat exchanger or the evaporator heat
exchanger of fewer than all of the heat pump units. In some
embodiments, the first HVAC fluid enters the heat pump through a
common inlet, then diverges to at least two separate heat pump
units, and then converges to exit the heat pump through a common
outlet. In embodiments having a dual-circuit heat pump, the method
can include selectively activating the second compressor of at
least one of the heat pump units to heat the first HVAC fluid if
the first HVAC fluid is circulating through the condenser heat
exchanger(s) or to cool the first HVAC fluid if the first HVAC
fluid is circulating through the evaporator heat exchanger(s).
Controlling the corresponding first electronic expansion valve(s)
can include remotely controlling at least one of the corresponding
first electronic expansion valve(s). In some such embodiments,
remotely controlling at least one of the corresponding first
electronic expansion valve(s) comprises controlling operation of
the at least one of the corresponding first electronic expansion
valve(s) based on input from one or more sensors of an HVAC system
that incorporates the heat pump.
[0049] Heat pumps according to the present invention can be
controlled in a variety of ways. FIGS. 3A-3B show illustrative
methods for controlling dual-circuit heat pumps (such as the heat
pump of FIG. 2). FIG. 3A shows an illustrative method for operation
of the heat pump, based on instructions provided regarding what is
needed from the heat pump. FIG. 3B shows an illustrative method for
monitoring for heat pump irregularities and triggering the heat
pump to turn off in the event that one or more of such
irregularities is detected.
[0050] Referring to FIG. 3A, the time variables (e.g., the heat
pump time on and time off variables) of the heat pump can be set
(200). The automatic controls can measure and record the time
duration a particular heat pump has been on or the time duration a
particular heat pump has been off. Outputs from the main controller
202 of the HVAC system can send a signal to the heat pump
controller indicating what is needed of the heat pump (204).
Sensors positioned throughout the HVAC system can provide input to
the main controller 202 concerning the conditions of the HVAC
fluid. For example, referring to FIG. 1A, the main controller of
the HVAC system can receive input from a temperature sensor reading
the temperature of the returning hot HVAC fluid. The main
controller can compare the desired conditions with the actual
conditions and determine what role the heat pump can play in
bringing the actual conditions into conformity with the desired
conditions. The main controller can generate instructions
concerning the role of the heat pump and can provide those
instructions to the heat pump controller, as indicated by step
(204) of FIG. 3A.
[0051] Referring again to FIG. 3A, the instructions provided by the
main controller 202 to the heat pump controller (204) can relate to
one or more of several variables of the heat pump. The operation of
a heat pump controller can be overridden and supervised
automatically by the main controller 202 or manually (e.g., by the
building operator) at the heat pump, at a local computer monitoring
the HVAC system, or through a network, such as the internet. For
example, the instructions can manually deactivate a heat pump for
servicing. The operations of an expansion valve controller can be
overridden and supervised automatically by the main controller 202
or manually (e.g., by the building operator) at the heat pump, at a
local computer monitoring the HVAC system, or through a network,
such as the internet. For example, the instructions can change the
superheat setpoint.
[0052] In many embodiments, the instructions call for the
activation or deactivation of one or both of the heat pump's
compressors. The heat pump controller can determine whether the
instructions call for deactivation of both compressors (deactivate
if activated or remain deactivated if already deactivated) (206).
If the heat pump controller determines that the instructions indeed
call for deactivation of both compressors, the heat pump controller
can signal both compressors accordingly (208, 210), which can
result in both compressors being stopped (212, 214). If the heat
pump determines that the instructions call for activation of at
least one compressor (activate if deactivated or remain activated
if already activated), the heat pump can move to the next level of
analysis.
[0053] If the heat pump controller determines that the instructions
call for activation of at least one of the compressors, the heat
pump controller can determine whether the instructions call for
activation of only one of the compressors (216) or activation of
both of the compressors (218). If the heat pump controller
determines that the instructions call for activation of only one of
the compressors, the heat pump controller can signal activation of
either compressor A (220) or compressor B (222). This can result in
a call of compressor A (224) or compressor B (226), pending
inspection for irregularities (described in greater detail below).
Whichever compressor is not called is/remains deactivated (212,
214).
[0054] When instructions call for activation of only one
compressor, the heat pump controller can call either compressor A
or compressor B based on an alternating or priority wear schedule.
If either compressor A or compressor B were always called in this
situation, that compressor would wear significantly faster than the
other. Accordingly, a schedule can be established to encourage even
wear of the two compressors or the preservation of one of the
components. The digital control of the embodiment can enable many
scheduling variations. In some embodiments, the heat pump
controller determines which of the compressors to call. In some
embodiments, the main controller determines which of the two
controllers to call.
[0055] When the heat pump controller determines that the heat pump
controller calls for activation of both compressors, the heat pump
controller can signal activation of the compressors in a staggered
fashion. In some instances, the heat pump controller can signal
activation of compressor A first, followed by activation of
compressor B after a time delay (228). This can result in (a) a
call of compressor A (224), pending inspection for irregularities,
(b) a period of delay as determined by reduced Amperage of the
first stage and verification after the delay of a continued need,
and (c) a call of compressor B (226), pending inspection for
irregularities. In some instances, the heat pump controller can
signal activation of compressor B first, followed by activation of
compressor A after a delay (230). This can result in (a) a call of
compressor B (226), pending inspection for irregularities, (b) a
period of delay and confirmations, and (c) a call of compressor A
(224), pending inspection for irregularities. Which compressor to
activate first is often determined according to a schedule designed
to reduce the likelihood of uneven wear between the compressors or
overall long-term reliability of the system. The heat pump
controller and/or the main controller can make this determination
in a manner similar to the determination of which compressor to
call when only one compressor is requested.
[0056] In some embodiments, the call for activation of a compressor
can open the source valve SV for the cold HVAC fluid to the
evaporator heat exchanger and open the load (moderate) valve MV for
the hot HVAC fluid to the condenser heat exchanger. In many
embodiments, the valves will close when both compressors are off.
Operating the valves in this manner can reduce the pumping costs of
the system, enable modules to operate at lower system flows, and
prevent refrigerant migrations within the heat pump system from
occurring when the heat pump is not active.
[0057] As alluded to above, before activating one or both of the
compressors, the heat pump can be inspected for one or more
irregularities (232, 234). Such an inspection can also be called a
safety inspection in reference to making sure that activation of
the compressor(s) will not damage the heat pump. If the heat pump
controller determines that activation of either of the compressors
(232, 234) would be unsafe, the heat pump controller can disable
the activation of the compressor(s) (212, 214). If the heat pump
controller determines that activation of one or both compressors
would not be unsafe (232, 234), the heat pump controller can
proceed with activation of the compressor(s) (236, 238).
[0058] FIG. 3B shows an illustrative method of monitoring for heat
pump irregularities and/or heat pump safety concerns. As can be
seen, the method of FIG. 3B includes eight tests. Other methods
according to the present invention may include a greater or lesser
number of tests. Other methods according to the present invention
may involve one or more of the tests illustrated in FIG. 3B in a
different order. A variety of tests, combinations, and orders are
possible.
[0059] The heat pump controller can first activate the method
(250). When a compressor is called, but before the compressor is
turned on, the method can be activated. If the method detects no
irregularities, the compressor can be turned on. In many
embodiments, while the compressor is turned on, the method can run
on a continuous basis. In such embodiments, if the method detects
an irregularity or safety concern while the compressor is
operating, the heat pump controller can cause the compressor to be
deactivated. In most embodiments, the method of FIG. 3B can be
performed in a relatively short period of time (e.g., once per
second) to accommodate active compressors.
[0060] In many embodiments, the method of FIG. 3B supplements, or
is supplemented by, protections that are hard-wired into the heat
pump components themselves. The hard-wired protections can monitor
for some or all of the irregularities that are monitored for by the
heat pump controller. In many such embodiments, the heat pump
controller safety tests are more conservative than those of the
hard-wired heat pump components. In many such embodiments, the heat
pump controller safety tests and the hard-wired safety tests can
serve as back ups to one another in the event that one of the
safety tests does not properly detect a potentially damaging heat
pump irregularity.
[0061] With the method in active mode, the heat pump controller can
run a variety of safety tests. One test can prevent compressors
from being subjected to repeated short cycles (252). A compressor
subjected to repeated short cycles can wear prematurely or be
damaged. Embodiments of the present invention can prevent short
cycles, thereby reducing the likelihood of premature wear of the
compressor or heat pump failure. The heat pump controller can
determine whether a compressor was just recently deactivated (e.g.,
within the past 10 or 15 minutes). In such a situation, the heat
pump controller typically delays activation of the compressor to
give it an appropriate amount of recovery (e.g., 10-15 minutes).
Given the large size of most HVAC systems and given the fact that
gradual changes in space conditions are typically desirable, the
delay in activation of one compressor does not typically impede
performance of the HVAC system.
[0062] If the heat pump controller determines that the compressor
was recently deactivated, the heat pump controller can generate an
alarm signal, signifying a condition in which operation of the
compressor would be unsafe to the compressor (254). If the test
identifies a potentially unsafe short cycle in compressor A, the
unsafe condition is associated with compressor A (256). If the test
identifies a potentially unsafe short cycle in compressor B, the
unsafe condition is associated with compressor B (258). Referring
to FIG. 3A, unsafe conditions associated with the respective
compressors are shown (256, 258). As alluded to above, if either of
these inputs (256, 258) indicate an unsafe condition, activation of
the corresponding compressor will be prevented.
[0063] Referring again to FIG. 3B, if the heat pump controller
determines that activating the called for compressor would not
result in a potentially unsafe short cycle, the heat pump can
administer additional safety tests. Another test monitors for
irregular or inappropriate current draw experienced by the relevant
compressor (260). Inappropriate current draw can result from, e.g.,
a change in load, a faulty power supply, and other reasons. If the
heat pump controller detects an irregular or inappropriate current
draw, the heat pump controller can generate a "high" signal,
signifying a condition in which operation of the compressor would
be unsafe to the compressor (254). As is discussed elsewhere
herein, this condition can be associated with a compressor, which
can prevent activation of, or deactivate, that compressor.
[0064] The third test of the illustrative method of FIG. 3B
monitors for abnormally low suction pressure (262). This test can
activate an alarm if the evaporator inlet refrigerant pressure is
below a determined safe level that would cause "slugging" or
fluidized refrigerant in damaging amounts to enter the compressor.
If allowed to enter the compressor, mechanisms can be bent or
broken. If the heat pump controller detects an abnormally low
suction pressure, the heat pump controller can generate a "low"
signal, signifying a condition in which operation of the compressor
would be unsafe to the compressor (254). As is discussed elsewhere
herein, this condition can be associated with a compressor, which
can prevent activation of, or deactivate, that compressor.
[0065] The fourth test of the illustrative method of FIG. 3B
monitors for abnormally high delivery pressure (264). This test can
activate an alarm if the condenser outlet refrigerant pressure is
above a determined safe level that would cause overheating and
burning of the compressor windings. If allowed to over-pressurize,
the compressor can be irreparably damaged. If the heat pump
controller detects abnormally high delivery pressure, the heat pump
controller can generate a "high" signal, signifying a condition in
which operation of the compressor would be unsafe to the compressor
(254). As is discussed elsewhere herein, this condition can be
associated with a compressor, which can prevent activation of, or
deactivate, that compressor.
[0066] The fifth test of the illustrative method of FIG. 3B
monitors for abnormally low source temperature (266). This test can
activate an alarm if the leaving HVAC fluid temperature is below a
predetermined minimum that can cause the HVAC fluid in the
evaporator to freeze or "gel" creating a "freeze rupture" in the
heat pump condenser. This event can lead to a splitting of the
plates in the condenser heat exchanger and leakage, a blockage of
the HVAC fluid flow, and low suction pressure of the refrigerant
flow. If the heat pump controller detects abnormally low source
temperature, the heat pump controller can generate a "low" signal,
signifying a condition in which operation of the compressor would
be unsafe to the compressor (254). As is discussed elsewhere
herein, this condition can be associated with a compressor, which
can prevent activation of, or deactivate, that compressor.
[0067] The sixth test of the illustrative method of FIG. 3B
monitors for abnormally high load temperature (268). This test can
be activated if the hot HVAC fluid leaving the heat pump condenser
is above a predetermined set point. If the leaving hot HVAC fluid
is too hot, it can lead to unsafe fluid temperatures in the HVAC
system with the potential for burning skin, damaging piping,
activating secondary alarms, and other events. In the event of high
load temperature, the compressor is deactivated until a
predetermined reset level is achieved. If the heat pump controller
detects abnormally high load temperature, the heat pump controller
can generate a "high" signal, signifying a condition in which
operation of the compressor would be unsafe to the compressor
(254). As is discussed elsewhere herein, this condition can be
associated with a compressor, which can prevent activation of, or
deactivate, that compressor.
[0068] The seventh test of the illustrative method of FIG. 3B
monitors for an abnormal positioning of the source valve (270).
This test can activate an alarm if the heat pump compressors are
called to turn on and the source valve is not in a position to
allow flow of the HVAC fluid through the heat pump evaporator. If
undetected, this event could cause secondary alarms (noted
elsewhere herein) that would be caused by low suction and
subsequent freeze rupturing. If the heat pump controller detects an
abnormal positioning of the source valve, the heat pump controller
can generate an "alarm" signal, signifying a condition in which
operation of the compressor would be unsafe to the compressor
(254). As is discussed elsewhere herein, this condition can be
associated with a compressor, which can prevent activation of, or
deactivate, that compressor.
[0069] The eighth test of the illustrative method of FIG. 3B
monitors for an abnormal positioning of the load valve (272). This
test can activate an alarm if the heat pump compressors are called
to turn on and the load valve is not in a position to allow flow of
the HVAC fluid through the heat pump condenser. If undetected, this
event could cause secondary alarms as noted herein that would be
caused by high discharge pressure and subsequent compressor
overheating. If the heat pump controller detects an abnormal
positioning of the load valve, the heat pump controller can
generate an "alarm" signal, signifying a condition in which
operation of the compressor would be unsafe to the compressor
(254). As is discussed elsewhere herein, this condition can be
associated with a compressor, which can prevent activation of, or
deactivate, that compressor.
[0070] Monitoring for heat pump irregularities, e.g., by the
illustrative method shown in FIG. 3B, can provide a variety of
advantages. Some methods can assure health and safety measures
related to the temperature of the HVAC fluid. Some methods can
attract attention to other failures in the overall HVAC system.
Some methods can help in the long-term control of the HVAC system.
Some methods can prevent permanent damage and premature wear of the
compressors or other components of the heat pump and secondary
components in the HVAC system. Some methods can maintain and
provide increased energy efficiency of the heat pump and the HVAC
system.
[0071] Many heat pump embodiments described herein can be assembled
according to a variety of methods. FIG. 4 provides an illustrative
heat pump assembly method. First, a heat pump frame can be
selected. The heat pump frame can be selected based on the size of
the heat pump and a variety of other factors. In some instances,
heat pumps can be combined to provide a 30-ton capacity, a 60-ton
capacity, or other desired capacity.
[0072] Compressors can be added to the heat pump frame (101). In
many embodiments, the compressor is a scroll compressor. The
compressor can be smooth in operation, compact, with good motor
protection. The compact size of such embodiments can permit the
compressor to be built into relatively small heat pump frames and
modules that can be introduced to retrofit spaces through normal
doorways. In some embodiments, the compressor includes relatively
few moving parts with better reliability. In some embodiments, the
compressor is quieter and more energy efficient than other
compressors. An example of a compressor that is suitable for some
embodiments of the present invention is the Copeland Scroll ZR380.
One advantage of using many such compressors according to
embodiments of the present invention is the relatively quiet
operation. Quiet operation of the compressor can enable a tolerable
noise level in a mechanical room, even with open construction of
some embodiments. This allows an operator to readily see piping
(e.g. to observe frosting, etc.) without the removal of covers or
other sound attenuation panels. One advantage of using many such
compressors according to embodiments of the present invention is
staging of capacity to achieve ideal compressor loading. Staging of
compressors on individual refrigeration circuits enhances
reliability and performance of the HVAC system.
[0073] Condenser and evaporator heat exchangers can be added to the
heat pump frame (102). The evaporator and condenser heat exchangers
can be piped with the relevant compressors (103) in common or
separate refrigerant circuits for the common hot and cold HVAC
fluids. In some embodiments, components of the dryer shell can be
silver soldered or Sil-Fos welded to minimize leaks. In some
embodiments, the core of the dryer can be removed and replaced
simply (e.g., without welding).
[0074] A pressure test can be conducted on the heat pump (104). The
pressure test can comprise adding nitrogen to the heat pump for a
period of 12 hours at a pressure of 250 psi. If the heat pump
passes the pressure test, it can be ready for the next step in the
assembly process. If the heat pump fails, the failing joint can be
fixed and the pressure test can be repeated until it passes
(104).
[0075] A control panel can be added to the heat pump frame (105).
The control panel can be prefabricated. In some embodiments, the
compressor mounting can be accessed through a hinged electrical
panel, thereby maintaining maintenance access if the heat pump
modules are connected side by side.
[0076] The various electrical components of the heat pump can be
wired (106). The heat pump can then be subjected to an electrical
test and safety certification. If the heat pump passes the
electrical test and safety certification, the heat pump assembly
process can be complete. If the heat pump fails the electrical
test, the faulty wiring can be repaired, and the heat pump wiring
and electrical components can be retested until the heat pump
passes the electrical test and achieves safety certification
(106).
[0077] Referring again to FIG. 1A, as mentioned above, the HVAC
system of FIG. 1A includes a network of pipes and valves for
distributing HVAC fluid to various components. The energy transfer
components of FIG. 1A, which are discussed in greater detail
elsewhere herein, are connected to one another via a main loop 50.
HVAC fluid can pass through the main loop 50 and, depending on the
circumstances, can also pass through one or more of the energy
transfer components. For example, in some heating operations, HVAC
fluid can enter the main loop 50, pass through the solar thermal
panel 10 and/or the laundry heat transfer component 12 and/or the
waste water heat transfer component 14 and/or the ground energy
transfer component 16 and/or the geothermal well system 18 and/or
the outdoor air energy transfer component 20 and/or the exhaust
heat transfer component 22 and/or the domestic cold water heat
exchanger 24. As the HVAC fluid passes through the one or more
energy transfer components during a heating operation, the HVAC
fluid can pick up heat from the energy transfer components, thereby
raising the temperature of the HVAC fluid. Depending on the
circumstances, the HVAC fluid may bypass one or more of the energy
transfer components (e.g., by closing the valves to the energy
transfer component(s)) as it passes through the main loop 50. In
some embodiments, the HVAC fluid from one or more energy transfer
components can be tied directly into the HVAC loops 40, 42 feeding
the conditioned space 6. This is shown in FIG. 1A for the solar
thermal panel 10, though it could be done for any individual energy
transfer component or combination of energy transfer
components.
[0078] In heating operations, HVAC fluid can pass through the
energy transfer component(s) on its way to the conditioned space 6
or on its way from the conditioned space 6. In some embodiments,
HVAC fluid travels from the output of the heat pump's condenser
heat exchanger 34 into the conditioned space 6, as well as into and
through the main loop 50 (or to one or more individual energy
transfer components), as well as back to the input of the heat
pump's condenser heat exchanger 34. In this way, the energy
transfer component(s) can provide HVAC fluid to the heat pump that
is warmer than it otherwise would be. In many such embodiments, the
energy transfer components can provide a larger change in
temperature. In some embodiments, HVAC fluid travels from the
output of the heat pump's condenser heat exchanger 34 through the
main loop 50 (or to one or more individual energy transfer
components) to the conditioned space 6 back to the input of the
heat pump's condenser heat exchanger 34. In this way, the energy
transfer component(s) can further warm HVAC fluid received from the
heat pump 8. In some embodiments, HVAC fluid can pass through one
or more energy transfer components between exiting the conditioned
space 6 and entering the heat pump 8 and also pass through one or
more energy transfer components between exiting the heat pump 8 and
entering the conditioned space 6. The control system of the heat
pump 8 can be regulated to account for the presence of one or more
energy transfer components.
[0079] The HVAC system of FIG. 1A includes a cooling loop 42 that
can be used in cooling operations. As shown in configuration 52,
valves can be used to channel HVAC fluid between the heat pump's
condenser heat exchanger 34 and the main loop 50 and/or between the
heat pump's evaporator heat exchanger 38 and the main loop 50. In
some embodiments, the valving configuration 52 may occur
individually for each energy transfer component. For example, HVAC
fluid can enter the cooling loop 42 (and be directed to the main
loop 50 by the system valving 52), pass through the ground energy
transfer component 16 and/or the geothermal well system 18 and/or
the outdoor air energy transfer component 20 and/or the exhaust
heat transfer component 22. In another example, HVAC fluid can
enter the cooling loop 42 (and be directed to the main loop 50 by
the system valving 52), pass through the solar thermal panel 10
and/or the laundry heat transfer component 12 and/or the waste
water heat transfer component 14 and/or the domestic cold water
heat exchanger 24. In another example, HVAC fluid can enter the
cooling loop 42 (and be directed to the main loop 50 by the system
valving 52) and pass through one energy transfer component while at
the same time the HVAC fluid can enter the heating loop 40 (and be
directed to a second loop by a valving configuration) and pass
through an energy rejection sink. Many variations are possible.
Again, depending on the circumstances, the HVAC fluid may bypass
one or more of the energy transfer components (e.g., by closing the
valves 52 to the energy transfer component(s)) as it passes through
the cooling loop 42 and the main loop 50.
[0080] As with heating operations, in cooling operations, HVAC
fluid can pass through the energy transfer component(s) which can
reject heat away from the conditioned space 6. In some embodiments,
HVAC fluid travels from the output of the heat pump's evaporator
heat exchanger 38 to the conditioned space 6 through cooling loop
42 and (by way of the valving configuration 52) the main loop 50
(or to one or more individual energy transfer components) back to
the input of the heat pump's evaporator heat exchanger 38. Energy
transfer components that absorb energy from the HVAC fluid when
their environments are warmer than the HVAC fluid become energy
rejection components. In this way, the energy transfer component(s)
can provide HVAC fluid to the heat pump that is cooler than it
otherwise would be. In some embodiments, HVAC fluid travels from
the output of the heat pump's evaporator heat exchanger 38 through
the cooling loop 42 and the main loop 50 (or to one or more
individual energy transfer components) to the conditioned space 6
back to the input of the heat pump's evaporator heat exchanger 38.
In this way, the energy transfer component(s) can further cool HVAC
fluid received from the heat pump 8. In some embodiments, HVAC
fluid can pass through one or more energy transfer components
between exiting the conditioned space 6 and entering the heat pump
8 and also pass through one or more energy transfer components
between exiting the heat pump 8 and entering the conditioned space
6. As noted above, the control system of the heat pump 8 can be
adjusted to account for the presence of one or more energy transfer
components. Thus, in many embodiments, HVAC fluid can recover
energy from, and/or reject energy to, one or more energy transfer
components. HVAC systems can include various individual valve
configurations enabling some of the energy transfer components to
serve as energy recovery components and others to serve as energy
rejection components. Many functional permutations and combinations
are possible.
[0081] As discussed elsewhere herein, many embodiments can perform
heating operations and cooling operations simultaneously. One or
more compressors can be activated, causing heat pump refrigerant to
cycle through the heat pump components. The heat pump refrigerant
can chill HVAC fluid at the evaporator heat exchanger 38 and
simultaneously heat HVAC fluid at the condenser heat exchanger 34.
In this way, heating and cooling different HVAC fluids can involve
no more compressor work than heating or cooling alone. HVAC systems
can include a variety of components, which can be configured and
operated in a variety of ways. Thus, embodiments of the present
invention can reliably and efficiently serve a wide variety of
applications.
[0082] FIG. 1B shows an illustrative HVAC system similar to that of
FIG. 1A. As can be seen, like the HVAC system of FIG. 1A, the HVAC
system of FIG. 1B includes a heat pump 8, a main loop 50 with
connections to various energy transfer components 10, 12, 14, 16,
18, 20, 22, 24, and a cooling loop 42 for heating and cooling zones
2, 4 of conditioned space 6. The HVAC system of FIG. 1B can also
provide heating for zones 54 and 56 of conditioned space 6. Some or
all of the HVAC fluid exiting the heat pump 8 can be routed through
a second heat pump 58 to further increase the temperature of a
second and separated HVAC fluid (often domestic hot water) before
it enters zones 54, 56 of conditioned space 6. Often, the kinds of
zones that would benefit from passing through multiple heat pumps
are zones that require HVAC fluid at significantly higher
temperatures (e.g., higher temperature domestic hot water, process
water for laundry use, process water for municipal or industrial
applications). When the HVAC fluid has passed through the second
heat pump 58, the HVAC fluid can pass to zones 54, 56 through
respective distribution boxes 62, 64.
[0083] HVAC systems according to embodiments of the present
invention can arrange two or three or any suitable number of heat
pumps (and/or groups of heat pumps arranged in parallel) in a
series relationship to progressively increase the temperature of
HVAC fluid passing through them. For example, a first heat pump can
increase the temperature of HVAC fluid from 15 degrees Fahrenheit
to 60 degrees Fahrenheit. A second heat pump can take that
60-degree HVAC fluid and increase its temperature to 120 degrees
Fahrenheit. A third heat pump can take that 120-degree HVAC fluid
and increase its temperature to 160 degrees Fahrenheit. This
sequence can continue until the temperature of the HVAC fluid
reaches a desired (e.g., selected, predetermined) level. In this
example, three heat pumps increase the temperature of HVAC fluid
from 15 degrees Fahrenheit to 160 degrees Fahrenheit. Even if
achieving this kind of temperature difference with a single heat
pump were feasible (which it most likely is not), the required
energy input would be significantly greater than it would be for
the incremental approach discussed herein. In some embodiments, the
temperature of domestic hot water can be raised to 140 degrees
Fahrenheit and process water to 160 degrees Fahrenheit. Thus, in
many instances, multiple heat pumps arranged in a series
relationship can provide additional functionality, improved system
reliability, reduced wear on components, and increased
efficiency.
[0084] Arranging multiple heat pumps in a series relationship can
provide certain advantages in some embodiments. In many
embodiments, each heat pump that is arranged in a series
relationship experiences less strain than a single heat pump
designed to achieve the same total temperature difference. In many
such embodiments, the multiple heat pumps arranged in series
provide for increased durability and longevity. In some
embodiments, heat pumps that are optimized for certain temperature
ranges can be selected. For example, in the example provided above,
the first heat pump can be configured for peak efficiency between
15 and 60 degrees Fahrenheit, the second heat pump can be
configured for peak efficiency between 60 and 120 degrees
Fahrenheit, and the third heat pump can be configured for peak
efficiency between 120 and 160 degrees Fahrenheit. A heat pump can
be optimized for a given temperature range by adjusting one or more
of a variety of factors. For example, different heat pump
refrigerants can be used in each of the ranges, with each heat pump
refrigerant having characteristics making it suitable for optimal
efficiency within a given temperature range. Different heat pumps
can operate at different pressures and/or with different heat pump
refrigerant volumes to provide optimum operation within different
temperature ranges. Though arranging multiple heat pumps in a
series relationship has been discussed in connection with
progressively increasing the temperature of HVAC fluid in heating
operations, the same kind of arrangement can progressively decrease
the temperature of HVAC fluid in cooling operations.
[0085] As discussed herein, a fourth aspect of the present
invention provides a method of achieving a predetermined
temperature difference in an HVAC fluid. The method can include
providing an initial heat pump (e.g., a heat pump discussed in
connection with the first aspect or other heat pumps discussed
herein) and a subsequent heat pump (e.g., a heat pump discussed in
connection with the first aspect or other heat pumps discussed
herein). The method can include connecting the initial heat pump
and the subsequent heat pump in series. The method can include
circulating the HVAC fluid through the initial heat pump to achieve
a first temperature difference in the HVAC fluid. The method can
include circulating the HVAC fluid through the subsequent heat pump
to achieve a second temperature difference. The first and second
temperature differences can sum to be approximately equal to the
predetermined temperature difference. The predetermined temperature
difference can be a temperature increase (e.g., of 150 F) or a
temperature decrease (e.g., of 150 F).
[0086] Referring again to FIG. 1A, the illustrative HVAC system
includes energy transfer components, as noted above. One of the
energy transfer components shown in FIG. 1A is a solar thermal
panel 10, which can assist the heat pump 8 in heating operations.
The solar thermal panel 10 of FIG. 1A includes four panels 30 that
collect solar thermal energy (though any number of panels 30 are
possible). Solar radiant energy passes through the glass cover of
the panel and is entrapped within the panel space. The solar
radiant heat that accumulates in the panel is absorbed and
transferred from the panel space to the radiant fins. The energy
absorbed by the fins dissipates to the attached piping at its
center. The energy transferred to the piping can be absorbed by the
HVAC fluid that is passing through the pipes. In this way, HVAC
fluid exiting the solar thermal panel 10 can be warmer than HVAC
fluid entering the solar thermal panel 10, thereby reducing the
amount by which the heat pump 8 must work to heat the relevant HVAC
fluid to effectuate the desired heating. In some embodiments, such
as that of FIG. 1A, the solar thermal panel 10 can be connected to
the main loop 50. In some embodiments, the solar thermal panel 10
can be connected directly to the heat pump 8. In some embodiments,
the solar thermal panel 10 can be connected to the domestic hot
water supply, either instead of the HVAC fluid or in addition to
the HVAC fluid (e.g., by running alternate piping circuits or the
use of a heat exchanger on a separate solar panel piping). Taking
advantage of heat provided by the solar thermal panel 10 can allow
HVAC systems to perform significantly more efficiently and
sustainably.
[0087] The HVAC system of FIG. 1A includes a laundry heat transfer
component 12 and a waste water heat transfer component 14 as energy
transfer components. The laundry heat transfer component 12 can
take advantage of laundry exhaust (e.g., dryer exhaust) that is at
a significantly higher temperature than the heat recovery HVAC
fluid. In many buildings, laundry exhaust is channeled to the
outside and into the surrounding air without the HVAC system taking
advantage of its heat. The waste water heat transfer component 14
can take advantage of waste water (e.g., from laundry process
water, shower drains, water closets, sink drains, etc.) that is at
a significantly higher temperature than the heat recovery HVAC
fluid. For example, the water running through shower drains is
often around 90 degrees Fahrenheit. In some embodiments, such as
that of FIG. 1A, both the laundry heat transfer component 12 and
the waste water heat transfer component 14 can be connected to the
main loop 50. In some embodiments, either one or both of the
laundry heat transfer component 12 and the waste water heat
transfer component 14 can be connected directly to the heat pump 8.
Recovering this heat and using it in a building's HVAC system can
significantly offset heating loads, increase heat pump efficiency,
along with regenerating heat sources and providing a more
sustainable system.
[0088] In many embodiments, the laundry heat transfer component 12
and the waste water heat transfer component 14 can have
substantially the same flow-through structure. FIGS. 5A-5B show an
example of such a structure. The flow-through heat transfer
component 300 can include two coaxial tubes 302, 304. Laundry
exhaust or waste water can pass through the interior of the inner
tube 304, through channel 306. In many embodiments, the
flow-through heat transfer component 300 can be substituted for a
section of piping in a laundry exhaust or a waste water drainage
system, with the inner diameter of tube 304 being smooth walled and
substantially the same as the inner diameter of the laundry exhaust
or waste water drainage system pipe. In this way, the flow path of
the waste water or laundry exhaust can be substantially unimpeded
by the structure that channels the HVAC fluid through the
flow-through heat transfer component 300. This can provide a
significant advantage over conventional plate-and-frame components
in that solid substances (e.g., laundry lint, human waste, bones
from kitchen drains, etc.) do not get trapped in the HVAC
structure, meaning that the heat can be recovered without hindering
the functionality of the laundry exhaust or waste water
systems.
[0089] The flow-through heat transfer component 300 of FIGS. 5A-5B
includes an inlet pipe 308 and a corresponding inlet connector 309,
as well as an outlet pipe 312 and a corresponding outlet connector
313. The inlet and outlet connectors 309, 313 can connect the
flow-through heat transfer component 300 to HVAC pipes, thereby
incorporating the flow-through heat transfer component 300 into an
HVAC system. Once connected, HVAC fluid can enter the flow-through
heat transfer component 300 through the inlet pipe 308 and then
pass into the channel 310 between the exterior of the inner tube
304 and the interior of the outer tube 302. As the HVAC fluid flows
within the channel 310 from the inlet pipe 308 toward the outlet
pipe 312, a barrier 314 guides HVAC fluid around and around the
inner tube 304 in a coil-like configuration. In many embodiments,
this flow path lengthens the amount of time the HVAC fluid is
within the flow-through heat transfer component 300 and in thermal
conductance with the laundry exhaust or waste water. In many
embodiments, this flow path increases the turbulence of the flowing
HVAC fluid, thereby enhancing the heat transfer of the HVAC fluid.
When the HVAC fluid has completed its path through the channel 310
along the barrier 314, it exits the flow-through heat transfer
component 300 through the outlet pipe 312. The HVAC fluid exiting
the flow-through heat transfer component 300 through the outlet
pipe 312 can be at a significantly higher temperature than the HVAC
fluid entering the flow-through heat transfer component 300 through
the inlet pipe 308.
[0090] The wall of the inner tube 304 can be configured to permit
maximum heat transfer between the laundry exhaust or waste water
and the HVAC fluid (e.g., can be made of thermally conductive
material, such as a metal). The thickness of the wall of the inner
tube 304 can relate to the thermal capacitance and absorptivity
from the inner heat source, which could flow in either direction.
The wall of the outer tube 302 can be made of thermally insulating
material (e.g., a type of plastic) or an insulated metal, thereby
inhibiting heat transfer between the HVAC fluid and the environment
surrounding the flow-through heat transfer component 300. Many
factors can be controlled to facilitate maximum heat transfer, such
as contact surface area, direction of source flow, HVAC fluid flow
rate, source flow rate, HVAC fluid temperature, and so on. In this
way, the heat from the laundry exhaust or the waste water can be
recovered and used in the HVAC system, allowing the HVAC system to
perform more efficiently and sustainably. In some embodiments, the
flow-through heat transfer component 300 can be used in reverse to
heat the fluid within channel 306. In some embodiments, one or both
of the inner and outer flows may be reversed. The insulating and
conducting materials can be interchanged or made of the same
material.
[0091] Referring again to FIG. 1A, the illustrative HVAC system can
include a ground energy transfer component 16. In certain ground
conditions, it is advantageous for the HVAC system to include pipes
that exit the building and pass through a portion of the ground to
take advantage of ambient ground energy. In some embodiments, such
as that of FIG. 1A, the ground energy transfer component 16 can be
connected to the main loop 50. In some embodiments, the ground
energy transfer component 16 can be connected directly to the heat
pump 8. Recovering this energy and using it in a building's HVAC
system can significantly increase efficiency, along with providing
a more sustainable system.
[0092] FIG. 6 shows an illustrative ground energy transfer
component 400, according to some embodiments of the present
invention. Like the flow-through heat transfer component of FIGS.
5A-5B, the ground energy transfer component 400 of FIG. 6 includes
two coaxial tubes 402, 404. The tubes 402, 404 are shown positioned
in the ground 406. In some embodiments, the tubes 402, 404 can be
positioned in water or in any other suitable thermal mass. In many
embodiments, the inner tube 402 is made of a material that is
relatively thermally insulative (e.g., High Density Polyethylene
[HDPE] plastic piping). In many embodiments, the outer tube 404 is
made out of material that is relatively thermally conductive (e.g.,
stainless steel). The outer surface of the outer tube 404 may have
a thin moisture barrier. Reasons for making the inner tube 402 of
thermally insulative material and/or the outer tube 404 of
thermally conductive material are discussed in greater detail
elsewhere herein.
[0093] The ground energy transfer component 400 of FIG. 6 includes
an inlet connector 407 and an outlet connector 408. The inlet
connector 407 can connect to an inlet pipe 409 of an HVAC system,
and the outlet connector 408 can connect to an outlet pipe 410 of
the HVAC system, thereby incorporating the ground energy transfer
component 400 into the HVAC system. In many embodiments, the inlet
pipe 409 and the outlet pipe 410 can be made of a plastic polymer,
such as a high-density polyethylene. As noted above, the outer tube
404 is often made of metal, meaning that the inlet connector 407
and the outlet connector 408 often have components that permit the
polymer HVAC pipes to interface with the metal exterior of the
ground energy transfer component.
[0094] In many embodiments, HVAC fluid can enter the ground energy
transfer component 400 from the inlet pipe 409 through inlet
connector 407 and can exit through the outlet connector 408 into
the outlet pipe 410. In some embodiments, HVAC fluid can enter the
ground energy transfer component 400 from the outlet pipe 410
through the outlet connector 408 and exit through the inlet
connector into the inlet pipe 409. In many embodiments, the
cross-sectional area of the connector by which the HVAC fluid
enters the ground energy transfer component can be smaller than the
cross-sectional area of the corresponding HVAC pipe, thereby
resulting in an increased flow velocity of the HVAC fluid. In many
embodiments, the flow volume of the HVAC fluid entering the ground
energy transfer component is substantially equal to the flow volume
of the HVAC fluid exiting the ground energy transfer component.
[0095] When HVAC fluid enters the ground energy transfer component
400 from the inlet pipe 409 via the inlet connector 407, the HVAC
fluid can flow downwardly in the channel 412 between the outer
surface of the inner tube 402 and the inner surface of the outer
tube 404. As the HVAC fluid flows downwardly within the channel
412, a barrier 414 guides the HVAC fluid around and around the
inner tube 402 in a coil-like configuration. In many embodiments,
the barrier 414 serves to maintain the inner tube 402 in a
generally concentric relationship with the outer tube 404. In many
embodiments, the barrier 414 can be constructed of deformable
tubing (e.g., plastic or metal). In some embodiments, the tubing
can be wrapped around the inner tube 402 to create coils in a
desired configuration. The tubing can be hot-air welded to the
inner tube 402 to substantially prevent HVAC fluid from flowing
straight down in the channel 412 as opposed to along the barrier
414.
[0096] The HVAC fluid completes its path through the channel 412
along the barrier 414 as it approaches the base 416 of the ground
energy transfer component 400. As the HVAC fluid approaches and
reaches the base 416, it enters the interior of the inner tube 402.
In many embodiments, HVAC fluid enters the interior of the inner
tube 402 through holes 420. In some embodiments, the lower end of
the inner tube 402 can be open, which can permit HVAC fluid to
enter the interior of the inner tube 402 through that opening. In
some embodiments, the inner tube 402 can have both holes 420 and an
open lower end. In embodiments having holes 420 and a closed lower
end, the inner tube 402 can be connected to the base 416 in a
substantially rigid manner, thereby reducing the tensile stress on
the plastic-to-metal or metal-to-metal adapters of the inlet
connector 407 and the outlet connector 408. In many embodiments,
the collective cross-sectional area of the holes 420 is greater
than the cross sectional area of the interior of the inner tube
402, thereby permitting ease of passage. In some embodiments, the
holes 420 can be arranged approximately symmetrically about the
inner tube 402. In this way, the flow momentum of the HVAC fluid
can be balanced due to flow through the each hole 420 being
countered by flow through one or more opposite holes 420.
[0097] The HVAC fluid then flows relatively laminarly upward in the
interior of the inner tube 402. The cross-sectional area of the
interior of the inner tube 402 can be significantly greater than
the cross-sectional area within the channel 412. In this way, flow
velocity within the inner tube 402 can be reduced, thereby
producing a more laminar flow. In many embodiments, the HVAC fluid
contacts significantly less surface of the ground energy transfer
component on the upward path than on the downward path. Similarly,
in most embodiments, the HVAC fluid can flow substantially
unimpeded by other surfaces within the inner tube 402, thereby
producing a more laminar flow. The upward path is also generally a
significantly shorter distance, without spiraling around the ground
energy transfer component 400. The HVAC fluid then exits the ground
energy transfer component 400 through the outlet connector 408 and
flows back into the outlet pipe 410. In such an embodiment, because
the vertical temperature gradient of the surrounding ground 406 is
opposite to that of the HVAC fluid in channel 412--during both
heating and cooling--the ground energy transfer component 400 can
serve as a cross-flow heat exchanger with the ground or ground
fluid.
[0098] As referenced above, the HVAC fluid can thermally react with
the ground 406 while in the ground energy transfer component 400.
The HVAC fluid within channel 412, as guided by barrier 414, can
thermally react with the ground. In many embodiments, this flow
path increases the amount of time that the HVAC fluid is in thermal
communication with the surrounding ground 406. In some embodiments,
the momentum of the HVAC fluid as it flows along the barrier 414
causes it to crash against the interior of the outer tube 404. This
turbulence can result in greater heat transfer between the HVAC
fluid and the surrounding ground 406. Turbulence can be increased
by providing increased flow velocity of the HVAC fluid; subjecting
the HVAC fluid to more frictional forces due to contacting the
barrier 414, the inner tube 402, and the outer tube 404; and/or by
subjecting the HVAC fluid to a greater degree of centripetal force.
As the HVAC fluid contacts the barrier 414, the inner tube 402, and
the outer tube 404, it should be noted that the outer tube 404
provides a larger surface area for heat transfer to occur and that
the HVAC fluid is contacting at the peak of its centripetal
velocity profile.
[0099] In some instances, the HVAC fluid recovers heat from the
ground 406, resulting in HVAC fluid that is warmer near the base
416 than the HVAC fluid near the inlet connector 407. In some
instances, the HVAC fluid dissipates heat to the ground 406,
resulting in HVAC fluid that is cooler near the base 416 than the
HVAC fluid near the inlet connector 407. Generally, the HVAC fluid
recovers heat from the ground 406 when the ground 406 is warmer
than the HVAC fluid, and the HVAC fluid dissipates heat to the
ground 406 when the ground 406 is cooler than the HVAC fluid. In
many instances, the HVAC fluid recovers heat from the ground when
the HVAC system is heating, and the HVAC fluid dissipates heat to
the ground when the HVAC system is cooling. The wall of the outer
tube 404 can be configured to permit maximum heat transfer between
the HVAC fluid and the ground 406 (e.g., can be made of thermally
conductive material, such as stainless steel).
[0100] The heat transfer properties can be enhanced by the surface
properties of the barrier 414, the angle of slope (pitch) of the
barrier 414, the size of the passageway between two sections of the
barrier 414, the flow rate of the HVAC fluid, the centrifugal
forces, other factors, or combinations thereof. In some
embodiments, the spaces between coils of the barrier 414 can be
non-uniform. For example, a single ground energy transfer component
can have some coils that are spaced further apart (e.g., in ground
with a higher recovery rate, such as an underground stream; in
ground with a convective heat transfer component, such as flowing
waste water) and other coils that are closer together (e.g., in
ordinary ground with a lower heat recovery rate). In this way, the
ground energy transfer component 400 can be tuned to the ground
conditions by adjusting the pitch of the barrier 414.
[0101] In many embodiments, the HVAC fluid in the interior of the
inner tube 402 can be generally thermally insulated, resulting in a
relatively constant temperature within the interior of the inner
tube 402. The wall of the inner tube 402 can be made of thermally
insulating material, thereby inhibiting heat transfer between the
HVAC fluid flowing through channel 412 and the HVAC fluid flowing
in the interior of the inner tube 402. The spiraling flow path can
create a velocity profile at the interface between the inner tube
402 and the HVAC fluid is relatively small, thereby resulting in
less heat transfer between the HVAC fluid in channel 412 and the
HVAC fluid in the interior of the inner tube 402.
[0102] Insulating the HVAC fluid within the interior of the inner
tube 402 can generally preserve the effect of the heat transfer
that occurred while HVAC fluid was flowing through channel 412. In
some embodiments, a small amount of heat may transfer between HVAC
fluid flowing within the inner tube 402 to HVAC fluid flowing
within the outer tube 404. In such embodiments, the heat is
transferred within the system, meaning that the heat is not lost to
the surrounding environment. Providing both a heat transfer path
and a return insulated path (or vice versa) can provide several
advantages, such as improving the total heat transfer, reducing the
volume of fluid, and improving the HVAC system response rate. In
this way, embodiments of the ground energy transfer component 400
can be easily integrated into HVAC systems. The ground energy
transfer component 400 can aid in recovering energy from the ground
406 (e.g., ground having the above-mentioned ground conditions) to
be used in HVAC systems.
[0103] In some embodiments, the flow path through the ground energy
transfer component 400 can be reversed. HVAC fluid can enter the
ground energy transfer component 400 from the outlet pipe 410 via
the outlet connector 408, flow downwardly within the interior of
the inner tube 402 toward base 416, flow back upwardly through
channel 412 (while recovering heat from the ground 406 or
dissipating heat to the ground 406), and then exit the ground
energy transfer component 400 to the inlet pipe 409 via the inlet
connector 407.
[0104] Embodiments of the ground energy transfer component 400 can
provide one or more of the following advantages. Some embodiments
are closed systems, meaning that they can accommodate HVAC fluids
such as antifreeze while remaining environmentally friendly. As
closed systems, the HVAC fluid is not affected by ground or water
minerals. In such embodiments, the welds in the outer tube and base
can be air tight, as can the relevant connectors. Some embodiments
provide more efficient heat transfer as compared with some closed
geothermal wells. Some embodiments provide equal or better heat
transfer as compared with open geothermal wells, but without
environmental exposure to the ground or mineral exposure to the
HVAC system. This increased efficiency can permit ground energy
transfer components that are significantly shorter than geothermal
wells. For example, many ground energy transfer component
embodiments are less than 50 feet long. Many ground energy transfer
component embodiments come in standard pipe lengths (e.g., 21 feet,
etc.). Many ground energy transfer component embodiments are
capable of fitting within a single (e.g., 6-inch diameter) bore
hole. Some embodiments have a significantly smaller footprint than
most conventional horizontal geothermal wells, some of which may be
buried in relatively shallow ground. Some embodiments, such as
those having outer tubes made of mill grade stainless steel, can
provide significantly enhanced durability. Some embodiments can be
used in connection with relatively small pumping heads and/or can
operate at relatively low flow rates. Some embodiments are
relatively inexpensive and/or simple to manufacture (e.g., due to
the simple construction, the wide availability of base materials,
etc.). Some embodiments provide the above-noted heat transfer
benefits without diminishing the appearance of the building into
which they are incorporated (e.g., they have no rejection towers,
propane tanks, exhaust stacks, etc.).
[0105] Many ground energy transfer components can be installed with
relative ease.
[0106] For example, a 4-inch hollow-stem auger can be inserted into
the ground at a desired depth. The ground energy transfer component
can then be slid into the interior of the auger. The auger can then
be removed from the hole, leaving the ground energy transfer
component intact. This can permit installation in even wet ground
conditions. It can also reduce or eliminate the need for holding
the hole open during installation. In installing ground energy
transfer components in rock, a 3.7-inch cored hole can be used,
thereby reducing the required amount of rock drilling. In many
instances, the ground energy transfer component can be
pre-fabricated, thereby simplifying on-site installation. A variety
of installation methods can be employed.
[0107] Some HVAC systems include multiple ground energy transfer
components 400. Multiple ground energy transfer components are
arranged in series in some systems. Multiple ground energy transfer
components are arranged in parallel in some systems. Some parallel
arrangements provide advantages, such as reduced resistance to flow
in the HVAC system and thus lower pumping costs.
[0108] Some embodiments of the ground energy transfer component can
be used in applications other than HVAC systems. Examples include
heaters for intakes of hydroelectric power dams, industrial
processes, and other suitable applications.
[0109] Referring again to FIG. 1A, one of the energy transfer
components of the illustrative HVAC system is a geothermal well
system 18. The geothermal well system 18 can channel HVAC fluid
down deep below the surface of the earth. In many embodiments, the
geothermal well system 18 includes one or more loops 44, each
comprising two pipes connected on their lower ends by a connector.
Often, the loops 44 extend roughly 150-400 feet below the surface
of the earth, where the temperature remains relatively constant.
For much of the northern United States, this temperature is around
45 degrees Fahrenheit. The geothermal well system 18 can be made of
thermally conductive material, thereby encouraging heat transfer
between the HVAC fluid running through the geothermal well system
18 and the ground. In many embodiments, the geothermal well system
18 can be made of plastic pipe, which can have limited thermal
conductivity. Generally, in heating operations, heat can be
transferred from the ground to the HVAC fluid, and in cooling
operations, heat can be transferred from the HVAC fluid to the
ground. In some embodiments, such as that of FIG. 1A, the
geothermal well system 18 can be connected to the main loop 50. In
some embodiments, the geothermal well system 18 can be connected
directly to the heat pump 8. In this way, the HVAC system can take
advantage of the relatively constant temperature beneath the
earth's surface, allowing the HVAC system to perform more
efficiently and sustainably.
[0110] One of the energy transfer components of the illustrative
HVAC system of FIG. 1A is an outdoor air energy transfer component
20. In many embodiments, it is advantageous to channel HVAC fluid
through pipes that are exposed to outdoor ambient air. For example,
in cooling the interior playing surface of an ice arena (e.g., to
20 degrees Fahrenheit) during peak winter and/or during cold
"off-electrical peak" evenings when the air is colder than 20
degrees Fahrenheit, the HVAC system can dissipate significant
amounts of heat to the outdoor ambient air while chilling the HVAC
fluid used for cooling the interior playing surface of an ice
arena. During the times when making ice with compressor work, the
warm HVAC fluid can dissipate its heat from the compressors. In
some embodiments, the outdoor air energy transfer component 20 is a
closed loop that conserves water and does not evaporate it. The
HVAC fluid can pass through the outdoor air energy transfer
component 20, and a fan 46 can blow outdoor ambient air across the
pipes containing HVAC fluid. In some embodiments, such as that of
FIG. 1A, the outdoor air energy transfer component 20 can be
connected to the main loop 50. In some embodiments, the outdoor air
energy transfer component 20 can be connected directly to the heat
pump 8. In this way, the HVAC system can take advantage of the
outdoor ambient air, allowing the HVAC system to perform more
efficiently and sustainably. In some situations, the outdoor air
energy transfer component 20 can be used in enclosed spaces that
simultaneously achieve a desired effect on the ambient air and the
HVAC fluid.
[0111] One energy transfer component of the illustrative HVAC
system of FIG. 1A is an exhaust heat transfer component 22. In many
instances, various kinds of exhaust (e.g., building relief air,
parking garage exhaust, general exhaust, non-grease kitchen
exhaust, kiln exhaust, etc.) is removed buildings without taking
advantage of the exhaust's thermal properties. HVAC fluid can be
channeled around a coil within the exhaust heat transfer component
22. Exhaust can pass by the coil, thereby thermally reacting with
the HVAC fluid. In this way, HVAC fluid exiting the exhaust heat
transfer component 22 can be warmer than HVAC fluid entering the
exhaust heat transfer component 22, thereby reducing the amount by
which the heat pump 8 must heat the relevant HVAC fluid to
effectuate the desired heating. In some embodiments, such as that
of FIG. 1A, the exhaust heat transfer component 22 can be connected
to the main loop 50. In some embodiments, the exhaust heat transfer
component 22 can be connected directly to the heat pump 8. In some
embodiments, the exhaust heat transfer component 22 can be
connected to HVAC fluid that is warmer than the exhaust air in
order to reject heat from the HVAC system. In this way, the HVAC
system can take advantage of the thermal properties of the
otherwise unused exhaust, allowing the HVAC system to perform more
efficiently and sustainably.
[0112] One energy transfer component of the illustrative HVAC
system of FIG. 1A is a domestic cold water heat exchanger 24. In
many instances, the domestic cold water provided to a building
(e.g., from a municipality) is warmer than it needs to be and/or
warmer than desired. For example, domestic cold water is often
provided at 45 degrees Fahrenheit and warmer, while cold water
coming out of the tap is commonly (and often preferably) only 37
degrees Fahrenheit. Accordingly, the domestic cold water heat
exchanger 24 can reduce the temperature of the domestic cold water
while providing the excess heat to the HVAC fluid flowing through
the domestic cold water heat exchanger 24. In this way, HVAC fluid
exiting the domestic cold water heat exchanger 24 can be warmer
than HVAC fluid entering the domestic cold water heat exchanger 24,
thereby reducing the amount by which the heat pump 8 must heat the
relevant HVAC fluid to effectuate the desired heating. In this way,
the domestic cold water can be made biologically safer and can be
made usable for cooling applications. In some embodiments, such as
that of FIG. 1A, the domestic cold water heat exchanger 24 can be
connected to the main loop 50. In some embodiments, the domestic
cold water heat exchanger 24 can be connected directly to the heat
pump 8. In this way, the HVAC system can take advantage of the heat
provided by cooling the domestic cold water, allowing the HVAC
system to perform more efficiently and sustainably.
[0113] In the illustrative HVAC system of FIG. 1A, the
above-mentioned network of pipes and valves can distribute
temperature-controlled HVAC fluid to the illustrated building zones
2, 4. Before the HVAC fluid flows to the building zones 2, 4, the
HVAC fluid can flow through respective distribution boxes 26, 28.
As discussed elsewhere herein, many buildings have several zones,
such as 20, 30, 40, or more zones. For example, in a hotel, each
room can constitute its own zone. In many embodiments of the
present invention, one distribution box is provided for each
building zone. The distribution boxes 26, 28 can provide more
precise temperature control to the building zones 2, 4. Moreover,
as is discussed elsewhere herein, many distribution boxes 26, 28
are indeed modular in that they can be easily exchanged in their
entirety if one or more of the components therein needs to be
repaired or replaced. In this way, the relevant building zone can
be isolated from the HVAC system (e.g., by shutting inlet and
outlet HVAC fluid valves) for only the relatively short period of
time required to exchange the distribution box, as opposed to
isolating that building zone for the often much longer period of
time required to repair or replace the relevant component(s). With
the distribution box removed from the HVAC system, the relevant
component(s) can be repaired or replaced in a shop location,
thereby preparing the distribution box to be reintroduced to an
HVAC system. The distribution box can be reintroduced to the same
HVAC system (in the same or different location) or in an entirely
different HVAC system.
[0114] In many instances, it is advantageous to build a complete
distribution box in a setting more conducive to construction (e.g.,
a machine shop), as opposed to interconnecting the various
components at the same time as installing the HVAC system. In many
such instances, the setting more conducive to the construction may
be located remotely from the HVAC system installation site. The
setting may employ more specifically trained or alternately waged
people to perform the task.
[0115] FIG. 7 shows an illustrative distribution box 500, according
to some embodiments of the present invention. As shown, the
distribution box 500 can include a hot HVAC fluid inlet pipe 502, a
cold HVAC fluid inlet pipe 504, a hot HVAC fluid outlet pipe 506,
and a cold HVAC fluid outlet pipe 508. Each of the inlet and outlet
pipes 502, 504, 506, 508 can have a corresponding connector.
Connector 514 can be connected to the hot HVAC fluid inlet pipe
502, connector 516 can be connected to the cold HVAC fluid inlet
pipe 504, connector 518 can be connected to the hot HVAC fluid
outlet pipe 506, and connector 520 can be connected to the cold
HVAC fluid outlet pipe 508. The distribution box 500 can include a
fan coil supply pipe 510 and a fan coil return pipe 512. Both of
the fan coil pipes 510, 512 can have a corresponding connector,
with connector 522 being connected to the fan coil supply pipe 510
and connector 524 being connected to the fan coil return pipe 512.
The fan coil pipes 510, 512 can enable the distribution box 500 to
be connected to a fan coil and/or to various HVAC terminal
devices.
[0116] The connectors 514, 516, 518, 520, 522, 524 of the
distribution box 500 can connect to HVAC pipes, thereby
incorporating the distribution box 500 into an HVAC system. In many
embodiments, the connectors 514, 516, 518, 520, 522, 524 of the
distribution box 500 can be configured to permit the distribution
box 500 to be connected to, and disconnected from, the remainder of
the HVAC system relatively quickly.
[0117] As noted, HVAC fluid can flow through the distribution box
500. HVAC fluid can flow into the distribution box 500 via the hot
HVAC fluid inlet pipe 502 and/or the cold HVAC fluid inlet pipe
504. A valve 526 can permit either hot HVAC fluid coming from the
hot HVAC fluid inlet pipe 502 or cold HVAC fluid coming from the
cold HVAC fluid inlet pipe 504 to pass through to pump 528. Pump
528 can pump the relevant HVAC fluid through the fan coil supply
pipe 510 and into a fan coil. In some embodiments, the HVAC fluid
can flow into the fan coil without the need of pump 528 (e.g., if
the rest of the HVAC system is designed to provide the requisite
pressure). After passing through the fan coil, the HVAC fluid can
re-enter the distribution box via the fan coil return pipe 512. A
valve 530 can channel the HVAC fluid out of the distribution box
500 via either the hot HVAC fluid outlet pipe 506 or the cold HVAC
fluid outlet pipe 508. The valves 526 and 530 can be configured
such that hot HVAC fluid and cold HVAC fluid do not mix. Hot HVAC
fluid from HVAC fluid inlet pipe 502 can return to the hot HVAC
fluid at hot HVAC fluid outlet pipe 506. Cold HVAC fluid from cold
HVAC fluid pipe 504 can return to the cold HVAC fluid at cold HVAC
fluid outlet pipe 508.
[0118] A controller 532 can control various aspects of the
distribution box 500. The controller 532 can be in electrical
communication with one or more inputs, such as thermostat 534.
Thermostat 534 can be positioned within the appropriate zone. One
or more individuals within the zone can manually adjust conditions
of the zone via thermostat 534, or thermostat 534 can operate
according to various pre-selected conditions. Other inputs that can
be in electrical communication with the controller 532 include
various sensors. For example, a temperature sensor can be
positioned in the fan coil supply pipe 510 such that the
temperature sensor can inform the controller 532 of the temperature
of the HVAC fluid entering the fan coil. Several other inputs are
used in various embodiments.
[0119] Based on information provided by one or more inputs, the
controller 532 can control various aspects of the distribution box
500. For example, the controller 532 can instruct valve 526 to
permit only hot HVAC fluid to pass through to the pump 528 (e.g.,
during a heating operation) or to permit only cold HVAC fluid to
pass through to the pump 528 (e.g., during a cooling operation). In
some instances, the controller 532 can control the flow rate and/or
displacement of the pump 528. In some embodiments, the controller
532 can instruct valve 530 to channel returning HVAC fluid through
the hot HVAC fluid outlet pipe 506 (e.g., during a heating
operation) or through the cold HVAC fluid outlet pipe 508 (e.g.,
during a cooling operation). In some instances, the controller 532
can (digitally) instruct the blower of the fan coil to various
pre-wired stages of speed or it can instruct the blower of the fan
coil to any increment of speed on a variable (analogue) signal.
[0120] Like other controllers discussed herein, the controller 532
can be implemented in digital electronic circuitry, integrated
circuitry, specially designed ASICs (application specific
integrated circuits), computer hardware, firmware, software,
electric relays and switches and/or combinations thereof. These
various implementations can include implementation in one or more
computer programs that are executable and/or interpretable on a
programmable system including at least one programmable processor,
which may be special or general purpose, coupled to receive data
and instructions from, and to transmit data and instructions to, a
storage system, at least one input device, and at least one output
device. These various implementations can include relays and
switches from a remote controller device (e.g., a thermostat) wired
or wirelessly connected to the assembled body of an embodiment of
the invention.
[0121] In many instances, the controller can be connected via a
network (e.g., a LAN, a WAN, the Internet, etc.) to other
components of the HVAC system. Examples of components to which the
controller 532 may be connected include controllers of other
distribution boxes, controllers for one or more of the various
energy transfer components, controllers for one or more heat pump,
operator input devices/stations, zone input sensors (e.g., a sensor
to indicate whether the zone has transitioned from a closed system
to an open system, such as through the opening of a door or
window), and other suitable components. In this way, an operator
(e.g., a hotel employee at the front desk) can provide instructions
to the controller 532, such as whether the zone is occupied, one or
more set-point temperatures for the zone, changes to the set-point
temperature or limit set points, changes to the actual temperature,
whether to cease heating/cooling in the zone, and so on. In this
way, the operator can remotely control various HVAC conditions
within a given zone with relative ease.
[0122] In many HVAC system embodiments in which a controller and
corresponding pump(s) and valve(s) regulate the HVAC fluid entering
the fan coil, the HVAC fluid can enter only one coil within the fan
box, as opposed to two separate coils (one for cold HVAC fluid and
the other for hot HVAC fluid). FIG. 8 illustrates such a system.
Such a system can provide one or more of several advantages. Some
such systems can accommodate potable water as the HVAC fluid in
that there is a significantly lower likelihood that water will
remain stagnant in the fan coil. The controller can cause the pump
to regularly circulate the water in and through the fan box,
thereby preventing the water from becoming stagnant. This contrasts
with many two-coil systems in which water can remain stagnant for
six months or more (e.g., hot water in the hot water coil during a
long cooling season), leading to contamination and/or unacceptable
temperatures. Regularly circulating the water can dramatically
reduce the risk of contamination of the potable HVAC fluid, as well
as maintain the water at an acceptable temperature (e.g., hot water
above 115 degrees Fahrenheit). Some such systems can reduce the
likelihood of simultaneously heating and cooling a zone, thereby
reducing inefficiencies. Some such systems incorporate one larger
size coil, which can accomplish heating or cooling with HVAC fluid
at lower or higher temperatures, respectively. Some such systems
can operate in the absence of the heat pump in some circumstances
(e.g., when the one or more energy transfer components are capable
of providing HVAC fluid at the desired temperatures). Some such
systems can operate effectively by one or more smaller fans (e.g.,
having only one coil as opposed to two coils can reduce the static
pressure drop that the fan must overcome, allowing the fan to be
smaller and often using less energy and producing less noise).
[0123] Referring again to FIG. 7, in some embodiments, the
distribution box 500 is configured to accommodate potable water.
Valves, pumps, and other components can be constructed out of
materials (e.g., bronze, stainless steel, etc.) that do not erode
in such a way as to contaminate the potable water. Such systems can
include a bronze body circulating pump (e.g., Grundfos UP15-42 B7
or UP26-96 BF). The pumps can be 100% lead free circulators
suitable for potable water systems with 145 psi maximum operating
pressure and 176 degrees Fahrenheit maximum fluid temperature in a
104 degrees Fahrenheit maximum ambient temperature. In some
embodiments, the pumps can accommodate water from just above
freezing (e.g., 35.6 degrees Fahrenheit) up to approximately 230
degrees Fahrenheit. Some embodiments include a composite impeller
suitable for potable water. Many other variations are possible.
Systems that accommodate potable water often circulate the water to
prevent stagnation, whether or not circulation is needed for HVAC
purposes.
[0124] Distribution components similar to the distribution box 500
of FIG. 7 can be incorporated into other locations in HVAC systems.
For example, some energy transfer components can be used in both
heating and cooling operations. Examples from FIG. 1A include the
ground energy transfer component 16, the geothermal well system 18,
the outdoor air energy transfer component 20, and the exhaust heat
transfer component 22. A distribution box can be connected between
such energy transfer components and, e.g., the main loop 50. Such a
distribution box can include one or more valves, controllable by a
controller, that channel either hot HVAC fluid (e.g., during
heating operations) or cold HVAC fluid (e.g., during cooling
operations) through the energy transfer component. Some
distribution boxes that are incorporated into other locations in
HVAC systems can have similar characteristics to the distribution
box of FIG. 7, meaning that they can be swapped out quickly and
efficiently.
[0125] In the foregoing detailed description, the invention has
been described with reference to specific embodiments. However, it
may be appreciated that various modifications and changes can be
made without departing from the scope of the invention as set forth
in the appended claims. Thus, some of the features of preferred
embodiments described herein are not necessarily included in
preferred embodiments of the invention which are intended for
alternative uses.
* * * * *