U.S. patent application number 14/163793 was filed with the patent office on 2014-07-31 for dual sensor companion water heater.
The applicant listed for this patent is Weil-McLain. Invention is credited to Ryan Hardesty, Dan Karch, David King, Aaron Smith.
Application Number | 20140209042 14/163793 |
Document ID | / |
Family ID | 51221563 |
Filed Date | 2014-07-31 |
United States Patent
Application |
20140209042 |
Kind Code |
A1 |
Hardesty; Ryan ; et
al. |
July 31, 2014 |
Dual Sensor Companion Water Heater
Abstract
A hot water heater appliance includes a boiler, companion water
heater, and a controller. The companion water heater has a hot
water storage tank. The controller is configured to control the
water heater appliance in response to a sensed temperature at an
upper portion of the hot water storage tank and a sensed
temperature at a lower portion of the hot water storage tank. The
controller is configured to control the boiler to quickly heat
water in the hot water storage tank in response to both upper and
lower temperatures of the hot water storage tank being below a
predetermined temperature and the controller is configured to more
slowly heat water in the hot water storage tank in response to the
upper temperature of the hot water storage tank being above the
predetermined temperature and the lower temperature of the hot
water storage tank being below the predetermined temperature.
Inventors: |
Hardesty; Ryan; (Valparaiso,
IN) ; Karch; Dan; (La Porte, IN) ; King;
David; (Michigan City, IN) ; Smith; Aaron; (La
Porte, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Weil-McLain |
Michigan City |
IN |
US |
|
|
Family ID: |
51221563 |
Appl. No.: |
14/163793 |
Filed: |
January 24, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61757056 |
Jan 25, 2013 |
|
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|
Current U.S.
Class: |
122/14.3 ;
122/18.5; 122/19.1 |
Current CPC
Class: |
F24H 1/18 20130101; F24H
9/2007 20130101; F24D 17/0026 20130101; F24H 1/182 20130101; F24H
1/186 20130101; F24H 9/124 20130101; F24H 1/208 20130101; F24H
9/148 20130101; F24H 1/22 20130101; G05D 23/1931 20130101; F24D
17/0089 20130101; F24D 19/1051 20130101 |
Class at
Publication: |
122/14.3 ;
122/18.5; 122/19.1 |
International
Class: |
F24H 9/20 20060101
F24H009/20; F24H 1/18 20060101 F24H001/18; F24H 9/12 20060101
F24H009/12 |
Claims
1. A hot water heater appliance, comprising: a boiler; a companion
water heater having a hot water storage tank; and a controller
configured to control the water heater appliance in response to a
sensed temperature at an upper portion of the hot water storage
tank and a sensed temperature at a lower portion of the hot water
storage tank, wherein the controller is configured to control the
boiler to provide a boiler water to the hot water storage tank at a
temperature above a predetermined temperature in response to both
of the sensed temperature at an upper portion of the hot water
storage tank and the sensed temperature at a lower portion of the
hot water storage tank being below the predetermined temperature
and the controller is configured to control the boiler to provide
the boiler water to the hot water storage tank at a temperature at
the predetermined temperature in response to the sensed temperature
at an upper portion of the hot water storage tank being above the
predetermined temperature and the sensed temperature at the lower
portion of the hot water storage tank being below the predetermined
temperature.
2. The hot water heater appliance according to claim 1, wherein the
controller is configured to determine an amount of energy usage
from the hot water storage tank in response to a sensed decrease in
temperature at the lower portion of the hot water storage tank.
3. The hot water heater appliance according to claim 1, wherein the
controller is configured to automatically control the boiler to
provide maximum energy to the hot water storage tank in response to
a sensed decrease in temperature at the lower portion of the hot
water storage tank followed by a sensed decrease in temperature at
the upper portion of the hot water storage tank within a
predetermined amount of time.
4. The hot water heater appliance according to claim 3, further
comprising: a heat exchange coil disposed in the hot water storage
tank.
5. The hot water heater appliance according to claim 4, further
comprising: a lower sensor disposed in thermal contact with the
lower portion of the hot water storage tank; an upper sensor
disposed in thermal contact with the upper portion of the hot water
storage tank;
6. The hot water heater appliance according to claim 5, further
comprising: a circulator pump to urge a flow of a heating fluid to
circulate between a boiler and the heat exchange coil;
7. The hot water heater appliance according to claim 1, further
comprising: an insulating jacket disposed around, below, and above
the hot water storage tank, the insulating jacket having an
expanded polypropylene insulation layer and the insulating jacket
including a plurality of segments releasably fastened to each
other.
8. The hot water heater appliance according to claim 1, further
comprising: an ambient sensor to sense an ambient temperature.
9. A companion water heater comprising: a hot water storage tank; a
heat exchange coil disposed in the hot water storage tank; a lower
sensor disposed in thermal contact with a lower portion of the hot
water storage tank; an upper sensor disposed in thermal contact
with an upper portion of the hot water storage tank; a circulator
pump to urge a flow of a heating fluid to circulate between a
boiler and the heat exchange coil; and a controller configured to
control a heat source in response to a sensed temperature at an
upper portion of the hot water storage tank and a sensed
temperature at a lower portion of the hot water storage tank,
wherein the controller is configured to control the heat source to
provide a boiler water to the hot water storage tank at a
temperature above a predetermined temperature in response to both
of the sensed temperature at an upper portion of the hot water
storage tank and the sensed temperature at a lower portion of the
hot water storage tank being below the predetermined temperature
and the controller is configured to control the heat source to
provide the boiler water to the hot water storage tank at a
temperature at the predetermined temperature in response to the
sensed temperature at an upper portion of the hot water storage
tank being above the predetermined temperature and the sensed
temperature at the lower portion of the hot water storage tank
being below the predetermined temperature.
10. The companion water heater according to claim 9, wherein the
controller is further configured to control the heat source in
response to a scheduled plurality of performance modes based on a
preset schedule, wherein a first performance mode is scheduled to
be performed at an expected low usage time and a second performance
mode is scheduled to be performed at an expected high usage time
relative to the expected low usage time.
11. The companion water heater according to claim 9, wherein the
controller is configured to determine an amount of energy usage
from the hot water storage tank in response to a sensed decrease in
temperature at the lower portion of the hot water storage tank.
12. The companion water heater according to claim 9, wherein the
controller is configured to automatically control the boiler to
provide maximum energy to the hot water storage tank in response to
a sensed decrease in temperature at the lower portion of the hot
water storage tank followed by a sensed decrease in temperature at
the upper portion of the hot water storage tank within a
predetermined amount of time.
13. The companion water heater according to claim 9, further
comprising: a thermostatic mixing valve assembly.
14. The companion water heater according to claim 9, further
comprising: an ambient sensor to sense an ambient temperature.
15. The companion water heater according to claim 9, further
comprising: a plurality of flexible connectors to fluidly connect
the heat exchange coil with the heat source.
16. The companion water heater according to claim 9, further
comprising: a domestic hot water outlet fluidly connected to the
hot water storage tank to supply domestic hot water.
17. The companion water heater according to claim 16, further
comprising: a domestic cold water inlet fluidly connected to the
hot water storage tank to replenish water drawn from the hot water
storage tank.
18. The companion water heater according to claim 9, further
comprising: a temperature and pressure relief valve fluidly
connected to the hot water storage tank.
19. A method of heating water in a water heater appliance, the
method comprising the steps of: receiving a plurality of upper
portion temperature measurements over a time period at a controller
configured to control the water heater appliance, the plurality of
upper portion temperature measurements being associated with an
upper portion of a hot water storage tank disposed in the water
heater appliance; receiving a plurality of lower portion
temperature measurements over the time period at the controller
from a lower portion of a hot water storage tank; controlling a
boiler in the water heater appliance with a controller to provide a
boiler water to the hot water storage tank at a temperature above a
predetermined temperature in response to both of the sensed
temperature at an upper portion of the hot water storage tank and
the sensed temperature at a lower portion of the hot water storage
tank being below the predetermined temperature and controlling the
boiler with the controller to provide the boiler water to the hot
water storage tank at a temperature at the predetermined
temperature in response to the sensed temperature at an upper
portion of the hot water storage tank being above the predetermined
temperature and the sensed temperature at the lower portion of the
hot water storage tank being below the predetermined
temperature.
20. The method according to claim 19, further comprising the step
of: determining an amount of energy usage from the hot water
storage tank in response to a sensed decrease in temperature at the
lower portion of the hot water storage tank.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application Ser. No. 61/757,056, filed on Jan. 25, 2013, titled
"COMPANION WATER HEATER FOR WM97+ GAS-FIRED BOILERS," the
disclosure of which is incorporated herein by reference in its
entirety.
FIELD OF THE INVENTION
[0002] This invention relates generally to a hot water heater. More
particularly, the present invention relates, for example, to a
water heater for use with a suitable boiler.
BACKGROUND OF THE INVENTION
[0003] Generally, domestic hot water is supplied via a water heater
appliance that is sized for the expected hot water draw.
Insufficient hot water can strongly negatively affect the comfort
of any occupants of the residence and lead to frustration and/or an
expensive replacement of the appliance. However, excessive hot
water capacity can lead to energy inefficiencies and poor
performance. Examples of water heater appliances include
traditional hot water heater tanks, `instant` hot water heaters
which are often called `tankless water heaters`, and indirect water
heaters. Commonly, each of these water heater appliances are a
compromise between water heater performance values such as: `peak
draw` performance; `continuous draw` performance; `first draw`
performance; efficiency; operating cost; and initial cost.
[0004] Peak draw performance is a measure of how much hot water is
available during peak demands. This is normally an increased amount
over what the appliance can produce continuously (e.g., continuous
draw performance) based on the amount of hot water the appliance is
storing. When this peak demand is at the beginning of the hot water
draw it is considered a "First Draw Performance". A Peak Draw Value
can be expressed as gallons per minute (GPM) at a specific
temperature rise for a limited period of time. This temperature
rise is a measure of the difference in temperature between the
incoming water supplying the water heater appliance and the hot
water supplied by the water heater appliance. After that time the
temperature of the water delivered will drop.
[0005] While conventional water heater appliances attempt to create
a good balance of water heater performance values, they typically
fail to efficiently provide both good peak draw and continuous draw
(or steady state) performance. Accordingly, there is a need in the
art to improve the water heater appliance.
SUMMARY OF THE INVENTION
[0006] The foregoing needs are met, to a great extent, by the
present invention, wherein aspects of a water heater appliance are
provided.
[0007] An embodiment of the present invention pertains to a hot
water heater appliance. The hot water heater appliance includes a
boiler, companion water heater, and a controller. The companion
water heater has a hot water storage tank. The controller is
configured to control the water heater appliance in response to a
sensed temperature at an upper portion of the hot water storage
tank and a sensed temperature at a lower portion of the hot water
storage tank. The controller is configured to control the boiler to
provide a boiler water to the hot water storage tank at a
temperature above a predetermined temperature in response to both
of the sensed temperature at an upper portion of the hot water
storage tank and the sensed temperature at a lower portion of the
hot water storage tank being below the predetermined temperature
and the controller is configured to control the boiler to provide
the boiler water to the hot water storage tank at a temperature at
the predetermined temperature in response to the sensed temperature
at an upper portion of the hot water storage tank being above the
predetermined temperature and the sensed temperature at the lower
portion of the hot water storage tank being below the predetermined
temperature.
[0008] Another embodiment of the present invention relates to a
companion water heater. The companion water heater includes a hot
water storage tank, a heat exchange coil, a lower sensor, an upper
sensor, a circulator pump, and a controller. The heat exchange coil
is disposed in the hot water storage tank. The lower sensor is
disposed in thermal contact with a lower portion of the hot water
storage tank. The upper sensor is disposed in thermal contact with
an upper portion of the hot water storage tank. The circulator pump
is to urge a flow of a heating fluid to circulate between a boiler
and the heat exchange coil. The controller is configured to control
a heat source in response to a sensed temperature at an upper
portion of the hot water storage tank and a sensed temperature at a
lower portion of the hot water storage tank. The controller is
configured to control the heat source to provide a boiler water to
the hot water storage tank at a temperature above a predetermined
temperature in response to both of the sensed temperature at an
upper portion of the hot water storage tank and the sensed
temperature at a lower portion of the hot water storage tank being
below the predetermined temperature and the controller is
configured to control the heat source to provide the boiler water
to the hot water storage tank at a temperature at the predetermined
temperature in response to the sensed temperature at an upper
portion of the hot water storage tank being above the predetermined
temperature and the sensed temperature at the lower portion of the
hot water storage tank being below the predetermined
temperature.
[0009] Yet another embodiment of the present invention pertains to
a method of heating water in a water heater appliance. In this
method, a plurality of upper portion temperature measurements are
received over a time period at a controller configured to control
the water heater appliance. The plurality of upper portion
temperature measurements are associated with an upper portion of a
hot water storage tank disposed in the water heater appliance. A
plurality of lower portion temperature measurements are received
over the time period at the controller from a lower portion of a
hot water storage tank. A boiler in the water heater appliance is
controlled with a controller to provide a boiler water to the hot
water storage tank at a temperature above a predetermined
temperature in response to both of the sensed temperature at an
upper portion of the hot water storage tank and the sensed
temperature at a lower portion of the hot water storage tank being
below the predetermined temperature and controlling the boiler with
the controller to provide the boiler water to the hot water storage
tank at a temperature at the predetermined temperature in response
to the sensed temperature at an upper portion of the hot water
storage tank being above the predetermined temperature and the
sensed temperature at the lower portion of the hot water storage
tank being below the predetermined temperature.
[0010] There has thus been outlined, rather broadly, certain
embodiments of the invention in order that the detailed description
thereof herein may be better understood, and in order that the
present contribution to the art may be better appreciated. There
are, of course, additional embodiments of the invention that will
be described below and which will form the subject matter of the
claims appended hereto.
[0011] In this respect, before explaining at least one embodiment
of the invention in detail, it is to be understood that the
invention is not limited in its application to the details of
construction and to the arrangements of the components set forth in
the following description or illustrated in the drawings. The
invention is capable of embodiments in addition to those described
and of being practiced and carried out in various ways. Also, it is
to be understood that the phraseology and terminology employed
herein, as well as the abstract, are for the purpose of description
and should not be regarded as limiting.
[0012] As such, those skilled in the art will appreciate that the
conception upon which this disclosure is based may readily be
utilized as a basis for the designing of other structures, methods
and systems for carrying out the several purposes of the present
invention. It is important, therefore, that the claims be regarded
as including such equivalent constructions insofar as they do not
depart from the spirit and scope of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a partial cross sectional and exploded view of a
hot water heater appliance suitable for use with an embodiment of
the present invention.
[0014] FIG. 2 is a block diagram of a system architecture for the
hot water heater appliance depicted in FIG. 1.
[0015] FIG. 3 is a block diagram of a controller for the hot water
heater appliance depicted in FIG. 1.
[0016] FIG. 4 is a block diagram of a method of controlling the hot
water heater appliance according to an embodiment of the present
invention.
DETAILED DESCRIPTION
[0017] Various embodiments of the present invention provide for an
improved hot water heater appliance that is configured to
efficiently provide excellent peak draw and steady state
performance and a method of controlling the hot water heater
appliance. In some embodiments, the hot water heater appliance
includes a variety of performance modes to optimize one type of
performance over others. The hot water heater appliance may be
configured to remain in a particular performance mode or change
from one mode to another depending on a variety of factors such as,
for example, a pre-programmed timed schedule, learned schedule,
domestic hot water (DHW) draw, and the like. It should be
understood, however, that the present invention is not limited to
any one performance mode and is generally more efficient and better
able to meet DHW draws than conventional water heating appliances.
Preferred embodiments of the invention will now be further
described with reference to the drawing figures, in which like
reference numerals refer to like parts throughout.
[0018] Turning now to the drawings, FIG. 1 is a partial cross
sectional and exploded view of a hot water heater appliance 10
suitable for use with an embodiment of the present invention. As
shown in FIG. 1, the hot water heater appliance 10 includes a
boiler 12, a companion water heater 14, and a user
interface/controller 16/18. In general, the boiler 12 is configured
to provide the energy to heat the DHW. The companion water heater
14 is configured to receive the energy from the boiler 12 to heat
the DHW. The user interface 16 is configured to provide for two way
communication between a user and the controller 18. In this regard,
the user interface 16 includes a display and keys or other such
output and input devices. In a particular example, the display
includes various menus to select and control modes of operation for
the boiler 12 and/or the hot water heater appliance 10. It is a
particular advantage of some embodiments that the user
interface/controller 16/18 automatically senses installation of the
companion water heater 14 and then automatically provide an
additional menu for the companion water heater 14. The controller
18 is configured to control the hot water heater appliance 10.
[0019] The boiler 12 includes any suitable boiler or device capable
of generating delivering energy to the hot water heater appliance
10. More particularly, the boiler 12 is configured to provide
heated water suitable to be transported to the location of energy
need. Examples of suitable boilers include: gas fired; oil fired;
electric; solar; geothermal; or the like. In a particular example,
the boiler is a gas fired boiler configured to heat a supply of
water that is then circulated between the boiler 12 and the
companion water heater 14. A specific example of a suitable boiler
includes the WM97+ manufactured by Weil-McLain of Michigan City,
Ind. 46360-2388 USA.
[0020] As shown in the exploded portion of FIG. 1, the companion
water heater 14 includes an insulated jacket 20, hot water storage
tank 32, sensors 34 and 36, mixing valve assembly 38, circulator
pump 40, boiler connectors 42, temperature and pressure relief
valve (T&P relief valve) 44, domestic cold water (DCW) in
connector 46, and domestic hot water (DHW) out connector 48. The
insulated jacket 20 includes any suitable insulating material. In
addition, the insulated jacket 20 includes any suitable protective
and/or aesthetically pleasing outer materials. Examples of suitable
materials for the insulated jacket 20, include foams, polymers,
metals, and the like. In a particular example, the insulated jacket
20 includes expanded polypropylene (EPP). The EPP insulated jacket
20 is configured to provide a structural jacket that may absorb
kinetic impacts resiliently while also providing thermal
insulation. In some embodiments, the insulated jacket 20 may be
made exclusively of EPP and it is an advantage of these embodiments
that the EPP material may be colored and have an aesthetically
pleasing surface as well as providing sufficient structural and
insulating properties.
[0021] As shown in FIG. 1, the insulated jacket 20 includes a
plurality of portions. These portions include structural,
insulating, and aesthetic features that greatly improve the hot
water heater appliance 10. For example, the insulated jacket 20 may
include a bridge 22, top 24A, bottom 24B, front 24C, and back 24D.
The bridge 22 or piping access cover may be configured to provide
insulation to the piping in the area between the boiler 12 and the
companion water heater 14. In addition, the bridge 22 may be
configured to aesthetically integrate the boiler 12 and the
companion water heater 14. It is an advantage of this aesthetic
integration that the hot water heater appliance 10 may be located
in a general living area of a domicile rather than closed away in a
utility closet. It is another advantage of this aesthetic
integration that the working components of the companion water
heater 14 are protected. It is yet another advantage of this
aesthetic integration and the good surface properties of EPP that
the companion water heater 14 may collect less dust than
conventional water heaters and boilers and may be easier to clean.
Also shown in FIG. 1, the insulated jacket 20 includes a plurality
of openings disposed in cooperative alignment with respective
inlets and outlets associated with the hot water storage tank
32.
[0022] The top 24A, bottom 24B, front 24C, and back 24D are
configured to provide the hot water storage tank 32 with insulation
to each respective area. For example the top 24A is configured to
insulate the top of the hot water storage tank 32 and reduce loss
of heat therefrom via radiant loss, thermal conduction, air
convection/infiltration and the like. Similarly, the bottom 24B,
front 24C, and back 24D are configured to insulate the bottom,
front and back (including the sides) of the hot water storage tank
32 and reduce loss of heat therefrom via radiant loss, thermal
conduction, air convection/infiltration and the like.
[0023] In some embodiments, the portions of the insulated jacket 20
may be removably attached to each other and/or the hot water
storage tank 32. For example, the portions of the insulated jacket
20 may include any suitable fastener such snaps, magnets, or the
like that are configured to attach to each other and/or to the hot
water storage tank 32. In particular examples, the insulated jacket
20 includes a plurality of fasteners 26A configured to align and
attach the bridge 22 to the boiler 12. In this manner, the
aesthetic integration of the boiler 12 and companion water heater
14 may be further enhanced by the alignment of one to the other. In
addition, the insulated jacket 20 may include magnetic fasteners
26B configured to releasably fasten the front 24C to the back 24D.
In this manner, the hot water storage tank 32 may be easily
accessed for maintenance evaluation and repair (e.g., welding or
other such operation). In contrast, conventional hot water tanks
are typically covered in spray foam that renders the tank
unserviceable. Another negative aspect of conventional spray foam
installations is that moisture may be maintained in contact with
the tank. The novel EPP `clamshell` insulated jacket 20 facilitated
drawing or wicking moisture from the surface of the hot water
storage tank 32.
[0024] Optionally, the top 24A and bottom 24B may include lips or
other structures configured to releasably lock into slots, grooves
or other such structures in the front 24C and back 24D. If
included, these structures lock the top 24A and bottom 24B within
the front 24C and back 24D when the front 24C and back 24D are
fastened and can be removed when unfastened. In a particular
example, the front 24C and back 24D include an annular top slot
disposed about an inside portion of the front 24C and back 24D
configured to retain the top 24A. In another particular example,
the front 24C and back 24D include an annular bottom slot disposed
about an inside portion of the front 24C and back 24D configured to
retain the bottom 24B. Also optionally, the companion water heater
14 may include leveling feet 28 configured to level and raise or
lower the companion water heater 14 in a manner known to those
skilled in the art.
[0025] The hot water storage tank 32 is configured to receive a
supply of domestic cold water and utilize energy in the form of
circulating boiler water from the boiler 12 to provide a supply of
domestic hot water. The hot water storage tank 32 itself includes a
shell of metal or other such material that is sufficiently strong
to contain hot water at standard household pressures of 50-70
pounds per square inch (psi) (345-483 kilopascals `kPa`). The hot
water storage tank 32 includes a heat exchange coil 50, exchange
inlet 52, exchange outlet 54, DCW inlet 56, and DHW outlet 58.
[0026] The sensors 34 and 36 are configured to sense a temperature
of the water in the hot water storage tank 32 and forward a signal
corresponding to this sensed temperature to the controller 18. The
sensors 34 and 36 may include any suitable temperature sensing
element such as, for example, a thermocouple, thermistor, or the
like. The sensor 34 may be placed in thermal contact with a lower
portion of the hot water storage tank 32. In general, the lower
portion of the water storage tank 32 represents the lowest
temperature in the water storage tank 32 due to the relatively
higher density of colder water as compared to warmer water and
because the DCW inlet 56 is disposed at the lower portion of the
water storage tank 32. The sensor 36 may be placed in thermal
contact with an upper portion of the hot water storage tank 32. The
upper portion of the water storage tank 32 generally represents to
hottest temperatures in the water storage tank 32. As such, the
temperature at the upper portion of the water storage tank 32
represents the hottest water that can be delivered at that
particular moment.
[0027] The mixing valve assembly 38 includes a thermostatic mixing
valve configured to mix outgoing DHW with a controlled amount of
incoming DCW to produce DHW at a predetermined maximum DHW
temperature. This predetermined maximum DHW temperature may be set
by the user or a technician on the mixing valve assembly 38 and/or
may be controlled by the controller 18. This allows the hot water
storage tank to store a relatively greater amount of thermal
energy. In this manner, a relatively higher volume of DHW at the
predetermined maximum DHW temperature may be provided for a given
volume of the hot water storage tank 32.
[0028] The circulator pump 40 is configured to urge water to flow
or circulate between the boiler 12 and the heat exchange coil 50.
The circulator pump 40 is controlled via the controller 18.
Typically, the circulator pump 40 is controlled to start
circulating the water or other heating fluid between the boiler 12
and the heat exchange coil 50 shortly before the boiler 12 begins
to supply energy to the boiler water and then continues to
circulate for some predetermined time after the boiler 12 stops
supplying energy to the boiler water or until a predetermined cool
down temperature in the boiler is reached. The circulator pump 40
may, optionally, include a check valve to stop or reduce the flow
of water between the boiler 12 and the heat exchange coil 50 while
the circulator pump 40 is unpowered. This unpowered flow may draw
out heat from the hot water storage tank 32 if left unchecked.
[0029] The connectors 42 may include any suitable conduit and/or
fittings for conveying boiler water between the boiler 12 and
companion water heater 14. In a particular example, the connectors
42 include flexible stainless steel piping suitable for fluidly
connecting the boiler 14 to the companion water heater 14.
[0030] In general, the heat exchange coil 50 is configured to
provide a conduit for water or other heated fluid from the boiler
12 to be conveyed through the hot water storage tank 32 and to
exchange the heat therein with the water in the hot water storage
tank 32. Of note, the boiler water and DHW are not mixed, but
rather, heat from the boiler water is imparted upon the DHW through
the material making up the heat exchange coil 50. To efficiently
exchange this heat, the heat exchange coil 50 may be made from a
conductive material such as metal and may have a relatively long,
circuitous path. In addition, the heat exchange coil 50 may
optionally include radiating fins or other such implement to
increase thermal exchange In other examples, the heat exchange coil
50 may be an external, jacket-style heat exchange or other such
heat exchanger.
[0031] FIG. 2 is a block diagram of a system architecture for the
hot water heater appliance 10 depicted in FIG. 1. As shown in FIG.
2, the controller 18 may be configured for two way communication
between the boiler 12, user interface 16, sensors 34 and 36, and
circulator pump 40. In addition, the controller 18 is optionally
configured for two way communication between the mixing valve
assembly 38 and/or an ambient sensor 64. In operation, the
controller is configured to receive user input from the user
interface 16 and, based on this user input, control the various
other components of the hot water heater appliance 10 to provide
DHW. The controller 18 may determine one or more aspects of the
temperature within the hot water storage tank 32 via the sensed
conditions at the sensors 34 and 36. For example, if the
temperature at the sensor 34 is dropping relatively quickly, the
controller 18 may determine DHW is being drawn out quickly (and DCW
is being drawn in quickly to replace it). In another example, if
the temperature at both the sensors 34 and 36 are falling very
slowly, then the controller 18 may determine that little or no DHW
is being drawn out. As such, the controller 18 may be able to
accurately determine draw without the added complication of a flow
meter.
[0032] Control of the boiler 12 may include sensing temperatures at
one or more locations, sensing gas or fuel flow, ignition,
ventilation control, and the like. These and other aspects of
controlling a conventional non-condensing or condensing boiler are
generally known to those skilled in the art. If the optional
ambient sensor 64 is included, the controller 18 is configured to
sense the ambient temperature and the ambient temperature may be
factored into the control of the hot water heater appliance 10. For
example, temperature loss in the hot water storage tank 32 is a
function of the difference in temperatures between the hot water
storage tank 32 and the ambient temperature. To reduce thermal loss
at time of relatively low ambient temperature, the controller 18
may maintain the temperature in the hot water storage tank 32 at a
relatively lower temperature. In another example, at times of
relatively low ambient temperature, DHW water usage may rise or
fall depending upon the habits of the users of the DHW. The
controller 18 may be configured to facture in ambient temperature
in order to learn DHW usage trends. These DHW usage trends may be
factored into the control of the hot water heater appliance 10 to
supply sufficient DHW efficiently.
[0033] FIG. 3 is block diagram of the controller 18 for the hot
water heater appliance 10 depicted in FIG. 1. As shown in FIG. 3,
the controller 18 includes a processor 70. This processor 70 is
operably connected to a power supply 72, memory 74, clock 76,
analog to digital converter (A/D) 78, and an input/output (I/O)
port 80. The I/O port 80 is configured to receive signals from any
suitably attached electronic device and forward these signals to
the A/D 78 and/or the processor 70. For example, the I/O port 80
may receive signals associated with temperature measurements from
one or more of the sensors 34, 36, and 64 and forward the signals
to the processor 70. In another example, the I/O port 80 may
receive signals via the user interface 16 shown in FIGS. 1 and 2
and forward the signals to the processor 70. If the signals are in
analog format, the signals may proceed via the A/D 78. In this
regard, the A/D 78 is configured to receive analog format signals
and convert these signals into corresponding digital format
signals. Conversely, the A/D 78 is configured to receive digital
format signals from the processor 70, convert these signals to
analog format, and forward the analog signals to the I/O port 80.
In this manner, electronic devices configured to receive analog
signals may intercommunicate with the processor 70.
[0034] The processor 70 is configured to receive and transmit
signals to and from the A/D 78 and/or the I/O port 80. The
processor 70 is further configured to receive time signals from the
clock 76. In addition, the processor 70 is configured to store and
retrieve electronic data to and from the memory 74. Furthermore,
the processor 70 is configured to determine signals operable to
modulate the boiler 12 and thereby control the amount of heat
imparted to the hot water storage tank 32. For example, in response
to the processor 70 determining the water in the hot water storage
tank 32 is below a predetermined minimum temperature, the processor
70 may forward signals to the various components of the boiler 12
and the circulator pump 40 to provide heat to the heat exchange
coil 50 and thereby heat the water in the hot water storage tank
32.
[0035] According to an embodiment of the invention, the processor
70 is configured to execute a code 82. In this regard, the
controller 18 includes a set of computer readable instructions or
code 82. According to the code 82, the controller 18 is configured
to modulate an amount of energy imparted into the hot water storage
tank 32 by the boiler 12. In addition, the controller 18 may be
configured to generate and store data to a file 84. This file 84
includes one or more of the following: sensed temperatures;
timestamp information; determined temperature profiles (e.g., rate
at which the temperature is rising or falling); user input
temperature profiles; recommended temperature profiles; DHW usage
trends; heating schedules of various performance modes; and the
like.
[0036] Based on the set of instructions in the code 82 and signals
from one or more of the sensors 34, 36, and 64, the processor 70 is
configured to: determine the thermal capacity presently in the hot
water storage tank 32; determine the temperature profile of the
water in the hot water storage tank 32; determine the outflow of
DHW from the hot water storage tank 32 based on the temperature
profile; determine DHW usage trends; and determine whether the
thermal capacity presently in the hot water storage tank 32 is
sufficient for the expected usage based on DHW usage trends or
current water temperatures based on signals from the sensors 34
and/or 36. For example, the processor 70 receives the sensed
temperature and/or an average sensed temperature, compares this to
previous temperatures over time to determine the current
temperature profile. The processor 70 compares the current
temperature profile to expected thermal loss without DHW usage
(e.g., standby loss) to determine if usage is occurring and, if so,
how much. In some performance modes, the processor 70 determines
whether this amount of usage will exceed the thermal capacity of
the hot water storage tank 32 and may fire the boiler 12
proactively to prevent the temperature of the outflow DHW from
falling below a predetermined minimum. In other performance modes,
the processor 70 may wait until the temperature of the outflow DHW
falls below the predetermined minimum before controlling the boiler
12 to fire. In addition, if the processor 70 determines that no DHW
draw is occurring, the processor 70 may wait until a draw occurs
before controlling the boiler 12 to fire. Optionally, processor 70
may be configured to periodically raise the temperature above a
biological killing temperature in order to insure biological growth
does not occur. For example, even if a user selects maximum
temperature below the biological killing temperature, the processor
70 may periodically raise the temperature above the maximum
temperature and the biological killing temperature in order to
ensure biological growth does not occur.
[0037] In various examples, knowing the temperature at the bottom
and top of the hot water storage tank 32, by virtue of the sensors
34 and 36 respectively, facilitates a greater flexibility and
improved efficiency as compared to systems without such
capabilities. In a first example, the processor 70 may use
information on incoming water temperature (as sensed by the
temperature sensor 34, for example) to adjust the temperature
profile to use the minimum energy needed to satisfy the DHW demand.
In a particular example, in the summer, warmer ground water
temperature would require less energy to raise the delivered DHW to
the same temperature as in the winter. As such, a lower boiler
water deliver temperature may be able to satisfy the same flow rate
in the summer as a higher delivery temperature would in the winter.
Lower boiler water temperatures allow the boiler 12 to run at a
higher efficiency.
[0038] In a second example, by knowing the temperature at both the
top and bottom of the tank, the processor 70 may change the target
boiler water temperature during a DHW draw in order to most
effectively meet the demand. The processor 70 may increase the
delivery temperature to facilitate transferring maximum energy to
the DHW. Also, in response to signals from the sensor 36, the
processor 70 may determine that the top of the hot water storage
tank 32 has reached its targeted temperature and may change
(decrease) the target boiler water temperature in order to limit
the energy added to the top of the hot water storage tank 32 while
still adding energy to the colder water at the bottom of the hot
water storage tank 32. This feature of the processor 70 drastically
increases the thermal storage of the hot water storage tank 32 by
adding the maximum amount of energy to the hot water storage tank
32 while preventing the hottest water in the hot water storage tank
32 from greatly overshooting its target temperature and is a great
improvement in the art. This symptom of overshooting a targeted DHW
delivery temperature is known to those familiar with the art as
thermal stacking. Thermal stacking can, in some circumstances, lead
to significantly hotter DHW than desired due to adding excessive
energy to the top of the storage tank in order to recover the
colder water in the tank to the desired temperature. It is an
advantage of embodiments described herein that significantly
greater control over this negative performance characteristic is
provided as compared to conventional storage water heaters.
[0039] FIG. 4 is a block diagram of a method 100 of controlling the
hot water heater appliance 10 according to an embodiment of the
present invention. Prior to performance of the method 100, the hot
water heater appliance 10 may be installed. It is an advantage of
the hot water heater appliance 10 that the various components to
connect the boiler 12 to the hot water storage tank 32 are packaged
as a kit and flexible to allow connection to a variety of boiler
configurations. For example, the boiler connectors 42 are flexible
to allow for different placement of inlet and outlet from the
boiler 12. Prior to and/or during performance of the method 100,
various program parameters may be input and stored to the file 84.
For example, the user or a technician may select a performance mode
such as, for example: Off-Disabled which is generally for service;
High performance which delivers the highest performance and
maximizes the thermal energy stored in the hot water storage tank
32; Normal performance which delivers a balance of performance and
energy efficiency; Economy which delivers the most energy
efficiency; Vacation mode which maintains the water in the hot
water storage tank 32 at a temperature sufficient to deter
freezing; and Scheduled which provides the user with the capability
to schedule different performance modes to be performed at
different times of the weekday and/or weekend; and Learning mode
which may accept some initial user input and then learn DHW usage
trends and alter the performance mode based on the DHW usage
trend.
[0040] At step 102, the controller 18 receives sensor measurements.
For example, some or all of the sensors 34, 36, and 64 may forward
signals corresponding to the temperature sensed by the sensors to
the controller 18.
[0041] At step 104, the controller 18 may determine temperatures at
the various locations, compare these sensed temperatures to target
temperatures, determine one or more temperature profiles over time,
and compare those one or more temperature profiles to predetermined
temperature profile(s). For example, based on these forwarded
signals, the controller 18 may determine the temperature at the
lower and upper portion of the hot water storage tank 32 and,
optionally, the ambient temperature. These determined temperatures
may be compared to a target temperature range and/or a target
temperature for the lower and upper portion of the hot water
storage tank 32, respectively. If the determined temperatures fall
outside the target temperature range or below the target
temperatures, the controller 18 may be configured to determine an
action to rectify the determined temperatures. In a particular
example, if the determined temperatures at the upper portion of the
hot water storage tank 32 falls below the target temperature for
the upper portion of the hot water storage tank 32, the controller
18 may be configured to modulate the boiler at step 114 to increase
the energy delivered to the hot water storage tank 32.
[0042] As described herein, a large disparity in temperatures
between the lower and upper portion of the hot water storage tank
32 may lead to an unwanted condition of `thermal stacking`. It is
an advantage of embodiments described herein that the controller 18
may be configured to identify temperature disparities that exceed a
predetermined maximum temperature variance and act to rectify the
temperature disparity. In a particular example, the controller 18
may be configured to lower the energy in the boiler water delivered
to the hot water storage tank 32 via the heat exchange coil 50. As
a result, energy can be imparted into portions of hot water storage
tank 32 with lower temperatures while not significantly raising the
temperature of portions of hot water storage tank 32 with higher
temperatures. In addition, depending on the boiler 12 (e.g., heat
source), generating lower energy boiler water may be more efficient
than generating higher energy boiler water. The efficiencies of the
boiler 12 at various energy levels may be factored into determining
the energy of the boiler water delivered to the hot water storage
tank 32 via the heat exchange coil 50.
[0043] Over time, at step 104, a temperature profile may be
determined for the lower and upper portion of the hot water storage
tank 32 and, optionally, the ambient temperature.
[0044] At step 106, the controller 18 may be configured to
determine DHW usage. For example, the temperature profiles of the
lower and upper portion of the hot water storage tank 32 and/or an
average thereof may be compared to standby loss. If these profiles
closely match or match within a predetermined amount, it may be
determined that no DHW is being drawn. If these profiles do not
match, the rate at which the sensed temperature profiles are
falling may be used to determine DHW usage.
[0045] At step 108, the controller 18 may be configured to
determine the amount of thermal energy presently stored in the hot
water storage tank 32. For example, the temperature at the lower
and upper portion of the hot water storage tank 32 may be used to
determine an average temperature or calculate a thermal gradient
within the hot water storage tank 32 and that value is then
multiplied by the volume of water in the hot water storage tank
32.
[0046] At step 110, the selected performance mode may be factored
into the determination about whether to add heat to the hot water
storage tank 32. For example in some performance mode, the
controller 18 may be configured to add thermal energy to the hot
water storage tank 32 in anticipation of outflow DHW falling below
the predetermined minimum. In other performance modes, the
controller 18 may be configured to wait until the temperature of
the outflow DHW falls below the predetermined minimum before adding
thermal energy to the hot water storage tank 32.
[0047] In general, the various performance modes provide a
combination of operating parameters of the hot water heater
appliance 10 that provide the user of the hot water heater
appliance 10 with the ability to select one general mode over
another without having to explicitly program each operating
parameter. For example, if the user selects the `Economy Mode` and
then a particular desired DHW temperature, the controller 18 may be
configured to adjust the temperature at the upper portion of the
hot water storage tank 32 to be near or at the desired DHW
temperature and also control the boiler 12 to deliver boiler water
to the hot water storage tank 32 at or slightly above the desired
DHW temperature. Use of the performance modes greatly simplifies
the operation of the hot water heater appliance 10 for the user.
Through calculations and lab testing, the performance modes have
been developed that can be selected by the user and that that
optimize the parameters (tank storage temperature, boiler
temperature, on/off temperature differentials, and others). These
can range from "Economy" mode to provide the best efficiency when
producing hot water, "High Performance" mode that provides the
maximum amount of hot water at the expense of efficiency,
"Vacation" to use a minimum amount of energy to keep the hot water
storage tank 32 from freezing, and other modes.
[0048] It is another benefit of some embodiments that the
performance modes may be scheduled by a technician or the user. The
user interface 16 provides the user with the ability to set the
schedule of when the different performance modes may be active. For
example, the "High Performance" mode may be scheduled in the
morning hours when hot water usage is high. The hot water heater
appliance 10 can be scheduled to then shift over to an "Economy"
mode or even "Off" during times the building would not be occupied.
This differs from conventional DHW supply systems that require the
contractor or user to program this schedule. In yet another
embodiment, the scheduling of the various modes may be based on
historical usage. For example, the hot water heater appliance 10
may be configured to learn that DHW usage increases at 7 am each
weekday morning followed by a period of no usage for 9 hrs and then
some small DHW draws between 6 pm and 11 pm. These and other
learned DHW usage habits may then be used to develop a schedule
that maximizes DHW availability and efficiency.
[0049] At step 112, the controller 18 may determine whether or not
to add thermal energy to the hot water storage tank 32. For
example, the controller 18 may utilize the determined values,
preset temperatures, preset performance mode. Based on the set of
instructions in the code 82, these and other factors may be weighed
to determine if thermal energy is to be added to the hot water
storage tank 32. The plurality of sensors 34 and 36 facilitates
greater flexibility and efficiency of the system. The combination
of the two sensors 34 and 36 can detect both the high temperature
at the upper portion of the hot water storage tank 32 as well as
the lower temperatures at the lower portion of the hot water
storage tank 32. Monitoring the current value of these sensors as
well as their rate of change can help the controller 18 determine
the inferred load on the boiler 12. If the upper sensor 36 slowly
drops in temperature, this can be indicative of a natural standby
loss of the hottest part of the tank and the controller 18 can be
configured to then respond with a high efficiency recovery because
there is no immediate need for hot water. If the lower temperature
sensor 34 begins to drop the controller 18 can determine if this is
indicating a flow rate of cold water coming into the hot water
storage tank 32. This can be used in lieu of a flow sensor with the
added benefit of temperature measurement that can be used for other
functions. Based on the speed of the temperature decrease at the
lower temperature sensor 34, the controller 18 can determine the
size of the heat demand and the boiler 12 or other such energy
source can be controlled to respond accordingly. If the controller
18 detects a drop in temperature at the lower sensor 34 followed by
a drop in temperature at the upper sensor 36, this can indicate a
very large flow/demand for hot water and the boiler 12 can be
controlled to aggressively add energy to the hot water storage tank
32 to try to meet the demand and recover the tank temperature. Of
note, the location and orientation of the sensors 34 and 36
depicted in FIG. 1 are for illustrative purposes only and may each
be located higher or lower on the hot water storage tank 32 and may
be oriented in any suitable manner.
[0050] In some DHW drawing circumstances, the controller 18 may
determine that a total tank recovery procedure is warranted. In
conventional systems with a single sensor, overheating the tank is
a common problem. When trying to recover the tank temperature with
a high temperature in the coil or inner tank (or any other type of
heat exchanger) a portion of the domestic tank can experience
overheating due to the fact that the boiler or energy source will
continue to add heat to the tank until the sensor location has
reached temperature. Often the sensor is not located at the highest
temperature location in the tank, which causes the excess heat to
be added to the tank. In various embodiments described herein, the
controller 18 is configured to control the boiler 12 to deliver a
high energy boiler water to recover the energy within the hot water
storage tank 32 quickly, and then in response to the upper sensor
36 (or wherever the highest temperature sensor is located) sensing
the target temperature, the boiler 12 is controlled to deliver a
lower energy boiler water to continue to add heat to the hot water
storage tank 32 without the potential or ability to heat any part
of the hot water storage tank 32 over the desired value. In a
particular example, the boiler 12 is controlled to deliver a boiler
water at the target temperature of the hot water storage tank 32 in
response to the temperature at the upper portion of the hot water
storage tank 32 having reached the target temperature but the lower
portion of the hot water storage tank 32 still being below the
target temperature. In this manner, overheating is reduced or
prevented while allowing the hot water storage tank 32 to reach a
maximum amount of energy heat stored within the hot water storage
tank 32. The boiler 12 may be controlled to continue to add energy
until it can no longer modulate down any further because the hot
water storage tank 32 is no longer absorbing energy and the return
water temperature coming back to the boiler increases and the
outlet water rises above the target temperature and the boiler 12
is then controlled to shut off. This "Total Tank Recovery" has
essentially fully charged the hot water storage tank 32 as if it
was a thermal battery. The first portion of the recovery being a
high performance mode heating and the last portion of the recovery
being performed at high efficiency mode heating.
[0051] If it is determined that thermal energy is to be added to
the hot water storage tank 32, then, at step 114, the boiler 12 is
controlled to increase energy output and the circulator pump 40 is
controlled to urge the flow of water to circulate between the
boiler 12 and the heat exchange coil 50. Following the step 114, it
is determined if further thermal energy is to be added to the hot
water storage tank 32 and this is continued until it is determined
that the hot water storage tank 32 has sufficient thermal energy.
Of note, in order to make this determination, the temperature of
the water in the hot water storage tank 32 is continually or
periodically sensed. If it is determined that the hot water storage
tank 32 has sufficient thermal energy, the temperatures are sensed
at step 102.
[0052] The many features and advantages of the invention are
apparent from the detailed specification, and thus, it is intended
by the appended claims to cover all such features and advantages of
the invention which fall within the true spirit and scope of the
invention. Further, since numerous modifications and variations
will readily occur to those skilled in the art, it is not desired
to limit the invention to the exact construction and operation
illustrated and described, and accordingly, all suitable
modifications and equivalents may be resorted to, falling within
the scope of the invention.
* * * * *