Note: Descriptions are shown in the official language in which they were submitted.
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SYSTEMS, METHODS, AND APPARATUS FOR PREVENTING
CONDENSATION IN REFRIGERATED DISPLAY CASES
RELATED APPLICATION
This application claims priority under 35 U.S.C. 119(e) to United States
Provisional Patent Application No. 61/700,303, titled Systems, Methods, and
Apparatus
for Preventing Condensation in Display Cases, filed on September 12, 2012, the
entire
contents of which are hereby incorporated herein by reference.
TECHNICAL FIELD
The present disclosure relates generally to the field of heater systems for
refrigerated display units and more particularly to systems, methods, and
apparatus for a
dual circuit anti-sweat heater control system.
BACKGROUND
Retail and other establishments that store and sell refrigerated items
frequently
must be concerned with condensation problems. It is a common practice in
commercial
refrigerators and freezers, referred to below as refrigerated display units,
to utilize a glass
display door/window with a large transparent window in it to provide easy
access for a
customer while allowing the customer to also see what is inside the
refrigerated display
unit. Frequently, the window makes up the majority of the door panel. Under
adverse
environmental conditions, condensation on the door/window frames of the unit
and
window panes and outer frame of the door can be a problem.
For example, a door to a refrigerated display unit in a store may be opened
frequently by customers. When this happens, the inside of the door, which may
be, for
example, at a temperature of -15 degrees Fahrenheit to 40 degrees Fahrenheit,
is
immediately exposed to the ambient air in the store, which is typically at a
much higher
temperature. Depending on the temperature and humidity levels of the ambient
air,
condensation may form on the cold outside surfaces of the door. If the
humidity is
relatively high, heavy condensation may form almost immediately, which can
completely
obscure the view through the door/window glass. This obviously is detrimental
to the
purpose of the window, which is to provide a clear view inside the cooler to
better
promote the products stored therein. Additionally, the condensation may be
heavy enough
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to cause the door/window to drip when opened or condensation on the door frame
to drip
down the front of the display unit. This is a particular problem in retail
stores where it can
create a slip hazard.
In an effort to reduce or eliminate these problems, it has become a common
practice to employ heaters in door windows and door frames of refrigeration
equipment.
These devices, which will be referred to as refrigerated display units below,
use small
electrical heating elements to raise the temperature of the door glass or
frame sufficiently
above the dewpoint temperature so that condensation is reduced or eliminated.
Door
heaters are used in both refrigerators and freezers, and both types of units
will be
understood to be included in the term refrigerated display unit as it is used
below. There is
a significant energy cost associated with using such devices, however. It
takes energy to
power the heaters, and the heat generated by these heaters must be removed
from the
refrigerated volume by the refrigeration system. The costs involved with door
heaters can
be substantial.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the present disclosure and certain
features
thereof, reference is now made to the following description, in conjunction
with the
accompanying figures briefly described as follows:
Figure lA is a perspective view of a refrigerated display unit configured to
include
the dual-circuit anti-sweat heater control system, and a smart controller in
accordance with
one exemplary embodiment;
Figure 1B is a partial-perspective view of the door frame for one of the doors
of
the refrigerated display unit in accordance with one exemplary embodiment;
Figures 2A and 2B are schematic diagrams of the dual-circuit anti-sweat heater
control system for use in the refrigerated display unit of Figure lA in
accordance with one
exemplary embodiment;
Figure 3 is a schematic diagram of an alternative anti-sweat heater control
system
having a single or dual-circuit heating control system for use in the
refrigerated display
unit of Figure lA in accordance with an alternate exemplary embodiment;
Figure 4 is a flowchart of a method for providing anti-sweat heating control
with
the dual-circuit anti-sweat heater control system of Figures 2A-B in
accordance with one
exemplary embodiment;
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Figure 5 is a flowchart of another method for providing anti-sweat heating
control
with the dual-circuit anti-sweat heater control system of Figures 2A-B in
accordance with
another exemplary embodiment;
Figure 6 is a flowchart of another method for providing anti-sweat heating
control
with the dual-circuit anti-sweat heater control system of Figures 2A-B in
accordance with
yet another exemplary embodiment;
Figure 7 is a flowchart of a method for providing anti-sweat heating control
with
the anti-sweat heater control system of Figure 3 in accordance with one
exemplary
embodiment;
Figure 8 is a perspective view of another example refrigerated display unit
configured to include the exemplary dual-circuit or single circuit anti-sweat
heater control
system and smart controller in accordance with one exemplary embodiment;
Figure 9 is a perspective view of yet another refrigerated display unit
configured to
include the exemplary dual-circuit or single-circuit anti-sweat heater control
system and
smart controller in accordance with one exemplary embodiment; and
Figure 10 is a flowchart of another method for providing anti-sweat heating
control
with the dual-circuit anti-sweat heater control system of Figures 2A-B or a
single-circuit
anti-seat heater control system in accordance with another exemplary
embodiment.
DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
Exemplary embodiments will now be described more fully hereinafter with
reference to the accompanying drawings, in which the exemplary embodiments are
shown.
The concepts disclosed and/or claimed herein may, however, be embodied in many
different forms and should not be construed as limited to the exemplary
embodiments set
forth herein; rather, these embodiments are provided so that this disclosure
will be
thorough and complete, and will fully convey the scope of that which is
disclosed to those
or ordinary skill in the art. Like numbers refer to like, but not necessarily
the same or
identical, elements throughout.
Figure lA is a perspective view of an exemplary refrigerated display unit 100
configured to include a dual-circuit anti-sweat heater control system in
accordance with
one exemplary embodiment. Figure 1B is a partial-perspective view of one of
the
door/window frames of the refrigerated display unit 100 according to one
exemplary
embodiment. Referring now to Figures lA and 1B, the exemplary display unit 100
can
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include a casing 101 which includes multiple walls 105, such a back wall 111,
an opposing
front wall 115, two or more side walls 120, a top wall or ceiling 125, and a
bottom wall or
floor 130. The walls 105 can define one or more cavities for storing products
within the
unit 100. The unit 100 can also include one or more cooling units 135 for
cooling the
cavity area. The front wall of the casing 101 can include one or more openings
that allow
access to the products within the casing.
One or more doors 102 can be pivotally or otherwise adjustably mounted to the
casing 101 to both cover and provide access to the openings. Each door 102 can
include
an outer frame 140 that surrounds the perimeter of a transparent material 145,
such as
glass or plastic. The outer frame 140 of the door 102 can be made of a
metallic material,
such as steel, aluminum, or any other material known to those of skill in the
art. Each
door 102 can also include a door handle 150 that can be coupled to or provided
in the
outer frame 140 or the transparent material 145 of the door 102. The door
handle 150 can
provide a means for rotatably opening the door 102 to access the contents
within the unit
100.
A casing door frame 103 is provided on the casing 101 and disposed along the
front wall for each corresponding door 102. The door frame 103 generally has
the same
perimeter shape as the door 102 and is configured to contact at least a
portion of the door
102 when the door 102 is in the closed position. For example, the metal frame
140
disposed along the outer periphery of the door 102 can contact the door frame
103 when
the door 102 is in the closed position. In the example shown in Figure 1A, the
door frame
103 would have a generally rectangular shape to match the generally
rectangular shape of
the door 102 so that the metallic outer frame 140 of the door 102 can be
mechanically,
magnetically, and/or thermally coupled to the door frame 103. For example,
heat can be
transferred from the door frame 103 to the metallic outer frame 140 of the
door by way of
thermal conduction.
As best seen in Figure 1B, the door frame 103 can include a first channel 106
and a
second channel 107 disposed along and within the door frame 103. The first
channel 106
is sized and shaped to receive a primary heating device for a primary heater
circuit. For
example, the channels 106, 107 can have a depth such that, when heating device
is
disposed therein, the top or outward facing portion of the heating device will
be flush with
the surface of the remainder of the door frame 103. In one exemplary
embodiment, the
primary heating device for the primary heater circuit is a small gauge heater
wire. While
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the first channel 106 is shown as being generally straight, in alternative
embodiments, the
first channel 106, and the primary heating device for the primary heater
circuit disposed
therein, can have a serpentine or other pattern to provide a greater amount of
surface area
contact for the primary heater circuit along the door frame 103.
The second channel 107 is sized and shaped to receive a secondary heating
device
for a secondary heater circuit. In certain exemplary embodiments, the primary
and
secondary heater circuits are electrically isolated or not electrically
coupled to one another.
In one exemplary embodiment, the secondary heating device for the secondary
heater
circuit is a small gauge heater wire. While the second channel 107 is shown as
being
generally straight along each edge of the door/window frame (such as around
each
opening) (to create a generally rectangular shape for the channel 107), in
alternative
embodiments, the second channel 107, and the secondary heating device for the
secondary
heater circuit disposed therein, can have a serpentine or other pattern to
provide a greater
amount of surface area contact for the secondary heater circuit along the
door/window
frame. Alternatively, the secondary heater circuit can be routed and
positioned anywhere
additional heat is needed in a refrigerated display unit to limit or prevent
condensation
build-up. While the example discussed above shows just one first channel 106
and second
channel 107, it is understood that the unit 100 can have a first 106 and
second 107 channel
about each opening, about a group of openings in the unit 100 or a single
first 106 and
second 107 channel for the entire unit 100.
Figures 2A and 2B are schematic diagrams of an exemplary dual-circuit anti-
sweat
heater control system 200 that can be incorporated into the refrigerated
display unit 100 of
Figures 1A-1B. Now referring to Figures 1A-2B, the exemplary dual-circuit anti-
sweat
heater control system 200 includes a primary heater circuit 105 and a
secondary heater
circuit 110. The primary heater circuit 105 and the secondary heater circuit
110 can be
disposed in or along the door frame 103 of the unit 100. For example, the
primary heater
circuit 105 can have at least a portion that is disposed in the first channel
106 and the
secondary heater circuit 110 can have a least a portion that is disposed in
the secondary
channel 107.
The primary heater circuit 105 is electrically coupled to a source of power
(not
shown) by way of a line conductor 205 and a neutral conduct 210. The primary
heater
circuit 105 has a top end and a bottom end and may be routed in a serpentine
shape 130 to
provide increased surface area contact along the door frame 103. In certain
exemplary
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embodiments, at least a portion of the primary heater circuit 105 is disposed
in the first
channel 106 and extends around the perimeter of each door frame 103 or around
portions
of the perimeter of each door/window frame only where needed. As discussed
above, in
certain exemplary embodiments, the primary heater circuit 105 includes a small
gauge
wire that emits heat through conduction to the surface of the respective door
frame 103
and to the outer frame of the door 102 when the door 102 abuts the door frame
103 in the
closed position.
The secondary heater circuit 110 is electrically coupled to a source of power
(not
shown) by way of a line conductor 215 and a neutral conductor 220. In certain
exemplary
embodiments, the source of power for the primary heater circuit 105 and the
secondary
heater circuit 110 is the same. Alternatively, the primary heater circuit 105
and the
secondary heater circuit 110 can have different sources of electrical power.
In certain
exemplary embodiments, at least a portion of the secondary heater circuit 110
is disposed
in the secondary channel 107 and extends around the perimeter of each door
frame 103.
As discussed above, in certain exemplary embodiments, the secondary heater
circuit 110
includes a small gauge wire that emits heat through conduction to the surface
of the
respective door/window frame 103 and to the outer frame of the door 102 when
the door
102 abuts the door frame 103 in the closed position.
The secondary heater circuit 110 can also be electrically and/or communicably
coupled to a sensor 120. The sensor 120 can be disposed adjacent to or remote
from the
door frame 103. Further, the sensor 120 can be coupled to the unit 100 or
positioned
elsewhere, as long as it is electrically and/or communicably coupled to the
secondary
heater circuit 110 or a controller controlling the secondary heater circuit
110. Typically
the sensor 120 will be placed in the same general area as the unit 100 where
humidity is
likely to be at the highest level. In one exemplary embodiment, the sensor 120
is coupled
along the top of the unit 100 adjacent the door frame 103. The exemplary
sensor 120 can
be a humidity sensor, a temperature sensor, or a dewpoint sensor.
Alternatively, the
sensor 120 represents more than one sensor (including any one of or
combination of the
sensor types previously stated) that is electrically and/or communicably
coupled to the
secondary heater circuit 110. The sensor 120 can include a relay 125 or switch
that is
electrically and/or communicably coupled to the secondary heater circuit 110.
In certain
exemplary embodiments, when the relay 125 is open, power does not flow through
the
secondary heater circuit 110 and the secondary heater circuit 110 does not
produce heat
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along the door frame 103. Alternatively, when the relay 125 is closed, power
flows
through the secondary heater circuit 110 and the secondary heater circuit 110
produces
heat along the door frame 103. While the exemplary embodiment of Figures 2A-B
does
not shown a sensor electrically coupled to the primary heater circuit 105, in
an alternative
embodiment (not shown), the sensor 120 or another sensor is electrically
and/or
communicably coupled to the primary heater circuit 105. This other sensor can
be a
humidity sensor, a temperature sensor, a dewpoint sensor or any combination
thereof,
similar to that described for the sensor 120 of the secondary heater circuit
110.
Figure 3 is schematic diagram of an alternative exemplary anti-sweat heater
control
system 300 that can be incorporated into the refrigerated display unit 100 of
Figure 1A.
Now referring to Figures 1A-B and 3, the exemplary anti-sweat heater control
system 300
includes a heater circuit 310 disposed along or within the door frame 315, a
controller 330
electrically and/or communicably coupled to the heater circuit 310, and a
sensor 320
electrically and/or communicably coupled to the heater circuit 310 and/or the
controller
330. In certain exemplary embodiments, the door frame 315 is the same or
substantially
similar to the door frame 103 of Figure lA and the heater circuit 310 is
disposed within a
channel (e.g., the first 106 or second 107 channel) of the door frame 315 in a
manner
similar to that described with reference to Figure 1B. In one exemplary
embodiment, the
heater circuit 310 is substantially similar to the secondary heater circuit
110 of Figure 2A.
The heater circuit 310 can include a small gauge wire to emit heat along the
surface of the
door frame 315 and can include a line conductor and a neutral conductor
electrically
coupled to a source of power. While the exemplary embodiment of Figure 3
presents a
single heater circuit 310, alternatively, two heater circuits similar to that
shown and
described with reference to Figures 1B and 2A-B can be used.
The exemplary door frame 315 further includes one or more temperature sensors
335 coupled along an outer surface of the door frame 315 and electrically
and/or
communicably coupled to the controller 330 and/or the heater circuit 310. In
certain
exemplary embodiments, three temperature sensors 335 are used and are disposed
along
different areas of the door/window frame 335. However, greater or fewer
numbers of
temperature sensors 335, such as one or more temperature sensors, can be
alternatively
used.
The exemplary system 300 also includes a controller 330 electrically and/or
communicably coupled to the heater circuit 310 and the temperature sensors
335. The
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controller can be positioned adjacent to or remote from the door frame 315
and/or the
sensor 320. The controller 330 provides control signals for activating and
deactivating the
heater circuit 310. For example, the controller 330 can include a relay 325 or
switch that
activates and deactivates the heater circuit 310. In alternative embodiments
where two
heater circuits are used, each heater circuit can be electrically and/or
communicably
coupled to the controller 330 or only one can be electrically and/or
communicably coupled
to the controller 330. In this alternative exemplary embodiment, the relay 325
can be, for
example, a double pole relay capable of operating both heater circuits, such
that one pole
is normally closed and one is normally open.
The controller 330 also includes temperature sensor contacts 340 for
electrically
and/or communicably coupling the temperatures sensors 335 to the controller
330. The
exemplary controller 330 can also include a data storage device 345. The data
storage
device 345 may be any suitable memory device, for example, caches, read only
memory
devices, and random access memory devices. The data storage device 345 can
also store
data, tables or executable instructions for use by the controller 330. The
data storage
device 345 can store data from the temperature sensors 335 the sensor 320 as
well as
record the amount of time or how often the heater circuit 310 is activated.
For example,
the data storage device 345 can record the dewpoint temperature from a
dewpoint sensor
320, the temperature readings from one or more of the temperature sensors 335,
and the
length or percentage of time that the heater 310 has been activated. In
embodiments using
the dual heater circuit, such as those shown and described in Figures 2A-B,
the data
storage device 345 may record on-time information individually for each heater
circuit as
well as the amount of power or the heater level for each heater circuit.
In certain exemplary embodiments, the controller 330 can also include a
temperature display 350 that provides a visual indication of the temperature
data received
by the controller 330 from one or more of the temperature sensors 340. In
addition, the
temperature display 350 can provide a visual indication of the dewpoint
temperature or
other information received by the controller 330 from the sensor 320. In
certain
exemplary embodiments, the temperature display 350 is a light emitting diode
(LED)
display and liquid crystal (LCD) display, an analog display, or any other
display known to
those of ordinary skill in the art. In certain exemplary embodiments, the
temperature
display 350 and/or controller also includes an alarm. The alarm can be audible
or visual.
For example, the alarm can emit a sound via a speaker (not shown) or a
blinking light or
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both when the temperature reading from one or more of the temperature sensors
335 are
below the dewpoint temperature or remains below the dewpoint temperature for a
predetermined or configurable amount of time. In certain exemplary
embodiments, the
predetermined amount of time can be anywhere between one second and two
hundred
minutes and can be pre-programmed in the controller 330 or programmable to an
amount
desired by a user at the controller.
The exemplary controller 330 can also include a remote monitoring device 355.
In
certain exemplary embodiments, the remote monitoring device 355 is a wireless
transmitter or transceiver or a Bluetooth transmitter for transmitting the
data stored or
received in the data storage device 345 and or controller 330 wirelessly to a
remote device
for viewing the data by a user or another computer device.
The system 300 also includes a sensor 320 electrically and/or communicably
coupled to the controller 330. The sensor 320 can be coupled to the unit 100
or positioned
elsewhere, as long as it is electrically and/or communicably coupled to the
controller 330.
In certain exemplary embodiments, the sensor 320 will be placed in the same
general area
as the unit 100 where humidity is likely to be at the highest level. In one
exemplary
embodiment, the sensor 320 is coupled along the top of the unit 100 adjacent
the door
frame 315. The exemplary sensor 320 can be a humidity sensor, a temperature
sensor, or a
dewpoint sensor, as shown in Figure 3. Alternatively, the sensor 320
represents more than
one sensor (including any one of or combination of the sensor types previously
stated) that
are electrically and/or communicably coupled to the controller 330.
Figure 4 is a flowchart of an example method 400 for providing anti-sweat
heating
control with the dual circuit anti-sweat heater control system of Figures 1-2B
or 1A-B and
3, in accordance with one exemplary embodiment. Referring now to Figures 1-4,
the
exemplary method 400 begins at the START step and proceeds to step 405 where a
heater
control system for a display case door/window is provided. In one exemplary
embodiment, the heater control system is the unit 100 and system 200 or 300
described in
Figures 1-2B or 1A-B and 3. In step 410, the primary heater circuit 105 is
operated at a
constant power level. In one exemplary embodiment, the power level of the
primary
heater circuit 105 is set to the lowest level that will output an amount of
heat along the
small gauge wire of the circuit 105 to prevent condensation along the
door/window frame
and the outer frame of the door/window during normal conditions, such as those
levels that
are less than or less than or equal to the preset levels discussed in step 420
below. For
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example, if the ambient dewpoint temperature is normally 58 degrees
Fahrenheit, the
power level or the amount of power provided to the primary heater circuit 105
will be
adjusted to maintain the temperature along the door/window frame and the outer
frame of
the door/window at a level above 58 degrees Fahrenheit. The primary heater
circuit 105 is
not typically intended to be sufficient when ambient conditions dramatically
differ from
the normal level.
The ambient humidity level is received in step 415. In one exemplary
embodiment, the ambient humidity level is sensed by the sensor 120 and can be
transmitted, for example, to the controller or relay 125. In this exemplary
embodiment,
the sensor 120 is a humidity sensor or a combination sensor that include the
ability to
detect humidity levels. In step 420, an inquiry is conducted to determine if
the ambient
humidity level is greater than a preset humidity level. For example, in
situations where the
sensor 120 or relay 125 make the determination, the sensor 120 or relay 125 is
set with a
preset humidity level. When the humidity level, as sensed by the sensor 120,
exceeds the
preset humidity level, the secondary heater circuit 110 will be activated for
a preset
amount or percentage of time. In one exemplary embodiment, the preset humidity
level is
fifty-five percent relative humidity. Alternatively, the preset humidity level
could be set
anywhere between 1-100 percent relative humidity. In an alternative
embodiment, the
information from the sensor 120 can be sent to a controller (such as a
controller having the
same features and functionality as that described with regards to controller
330) which
determines if the ambient humidity level is greater than the preset humidity
level. While
the exemplary embodiment describes determining if the ambient humidity is
greater than a
preset humidity level, alternatively the system can determine if the ambient
humidity is
greater than or equal to the preset humidity level.
If the ambient humidity level is less than, or less than or equal to, the
preset
humidity level, then the NO branch is followed back to step 415 to continue
receiving
ambient humidity level readings from the humidity sensor 120. On the other
hand, if the
ambient humidity level is greater than or greater than or equal to the preset
humidity level,
then the YES branch is followed to step 425, where relay 125 closes and power
is supplied
to the secondary heater circuit 110 for a predetermined amount or percentage
of time. In
one exemplary embodiment, the controller can send a signal to close the relay
125 based
on the determination made in step 420. In one exemplary embodiment, the amount
or
percentage of time that the secondary heater circuit 110 is activated is
dependent on the
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current humidity level reading from the sensor. For example, if the preset
limit is fifty-
five percent relative humidity and the reading from the sensor 120 is fifty-
six percent
relative humidity, the secondary heater circuit 110 is operated for forty
percent of the time
going forward, such as by being on for two minutes and then off for three
minutes, or any
other combination thereof to satisfy the percentage of time setting. As the
ambient
humidity level increases further above the preset humidity level, the
percentage of time
that the secondary heater circuit 110 is on is increased. For example the
percentage of
time that the secondary heater circuit 110 is on based on the ambient humidity
level
reading from the sensor 120 can follow the percentages shown in Table 1 below.
Ambient Humidity Level Percentage of Time Secondary Heater Circuit
is On
0-55% 0%
56% 40%
57% 55%
58% 70%
59% 85%
60-100% 100%
TABLE!
Table 1, shown above is only one example of a preset humidity limit, the
ambient
humidity levels and the amount that the secondary heater circuit is operated
based on the
ambient humidity levels and the preset humidity limit. While the exemplary
embodiment
shown above provides for a linear increase in the percentage of time that the
secondary
heater 110 is on, the increase could be non-linear in alternative exemplary
embodiments.
Further, the increase in percentage levels of on time could be spread out over
a greater
amount of relative humidity such that further step increases in percentage on
time are
realized. In addition, the present humidity level for initial activation could
be set at a level
that is greater than or less than the fifty-five percent humidity level
provided for in the
exemplary embodiment. As an additional option, in addition to or in the
alternative to
operating the secondary heater circuit 110 as described above, the operation
of the primary
heater circuit 105 can be adjusted such that the primary heater circuit 105
can be turned on
for the preset amount of time, instead of being on all the time, depending on
the humidity
level. This optional arrangement would provide additional energy savings if
needed or
desired. In another alternative embodiment, once activated, the secondary
heater circuit
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110 remains ON constantly until the humidity sensor 120 receives an subsequent
ambient
humidity reading that is less than or less than or equal to the preset
humidity level.
In yet another alternative exemplary embodiment, instead of varying the amount
of
time the secondary heater circuit is activated based on the ambient humidity
level, the
voltage level supplied to the secondary heater circuit can be varied based on
the ambient
humidity level in a manner substantially similar to that described in Figure
10 below. For
purposes of example, the ambient humidity levels shown above in Table 1 can be
substituted for the dewpoint temperature levels provided in Figures 5-8 to
show example
variations that can be provided in the voltage level of the secondary heater
circuit based on
differing electrical systems.
In step 430, subsequent ambient humidity level readings can be received by the
circuit and/or the controller from the humidity sensor 120. In step 435, an
inquiry is
conducted to determine if the subsequent humidity level is greater than or
greater than or
equal to the preset humidity level. As with step 420 above, the determination
can be made
by the sensor 120, the relay 125 or the controller (not shown). If the
subsequent humidity
level is greater than or greater than or equal to the preset humidity level,
the YES branch is
followed back to step 430 to continue receiving subsequent humidity level
readings from
the sensor 120. Alternatively, if the subsequent ambient humidity level
reading is less
than or less than or equal to the preset humidity level, the NO branch is
followed to step
440. In step 440, the relay 125 opens and the secondary heater circuit 110 is
deactivated.
In one exemplary embodiment, the controller can send a signal to open the
relay 125 based
on the determination made in step 435. In addition, optionally, if adjustments
to the
operation of the primary heater circuit 105 were made in a manner similar to
that
described in step 425, the primary heater circuit 105 can be adjusted to once
again operate
in its original operational state (e.g., operating constantly at a constant
power level). The
process then returns to step 415 to receive the next ambient humidity level
reading from
the humidity sensor 120.
While the exemplary embodiment of Figure 4 has been described with reference
to
a humidity sensor and humidity levels, in an alternative embodiment, the
method of Figure
4 could be modified to activate and deactivate the secondary heater circuit
110 based on
surface temperature readings from a temperature sensor 120 positioned along an
outer
surface of the door frame 103 or other surface being monitored and heated as
compared to
a preset temperature. For example, if the surface temperature reading is less
than, or less
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than or equal to, the preset temperature the secondary heater circuit 110 is
not activated.
On the other hand, if the surface temperature reading is greater than, or
greater than or
equal to, the preset temperature, then the relay 125 closes and power is
supplied to the
secondary heater circuit 110 for a predetermined amount or percentage of time
in a
manner substantially similar to those described above for the humidity sensor.
In one
exemplary embodiment, the amount or percentage of time that the secondary
heater circuit
110 is activated is dependent on the amount that the surface temperature
reading received
from the sensor 120 is above the present temperature limit. For example, if
the preset
temperature limit is 58 degrees Fahrenheit and the surface temperature reading
from the
sensor 120 is 59 degrees Fahrenheit, the secondary heater circuit 110 is
operated for forty
percent of the time, such as by being on for two minutes and then off for
three minutes, or
any other combination thereof to satisfy the percentage on setting. As the
surface
temperature increases further above the preset temperature limit, the
percentage of time
that the secondary heater circuit 110 is on is increased. For example the
percentage of
time that the secondary heater circuit 110 is on based on the surface
temperature reading
from the sensor 120 can follow the percentages shown in Table 2 below.
Degrees Fahrenheit Percentage of Time Secondary Heater Circuit
is On
0-58 0%
59 40%
60 55%
61 70%
62 85%
63 and above 100%
TABLE 2
Table 2, provided above, is only one example of the set-up for preset
temperature
limit, the actual surface temperature levels and the amount that the secondary
heater
circuit is operated based on the surface temperature and the preset
temperature limit.
While the exemplary embodiment shown above in Table 2 provides for a linear
increase in
the percentage of time that the secondary heater circuit 110 is on, the
increase could be
non-linear in alternative exemplary embodiments. Further, the increase in
percentage
levels of on time could be spread out over a greater amount of surface
temperatures such
that additional step increases in percentage on time are realized. In
addition, the preset
temperature for initial activation could be set at a level that is greater
than or less than the
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59 degrees Fahrenheit provided for in the exemplary embodiment. As an
additional
option, in addition to or in the alternative to operating the secondary heater
circuit 110 as
described above, the operation of the primary heater circuit 105 can be
adjusted such that
the primary heater circuit 105 can be turned on for the preset amount of time,
instead of
being on all of the time, depending on the sensed surface temperature. This
optional
arrangement would provide additional energy savings if needed or desired. In
another
alternative embodiment, once activated, the secondary heater circuit 110
remains ON
constantly until the surface temperature sensor 120 receives a subsequent
ambient
temperature reading that is less than, or less than or equal to, the preset
temperature limit.
In yet another alternative exemplary embodiment, instead of varying the amount
of
time the secondary heater circuit is activated based on the surface
temperature level, the
voltage level supplied to the secondary heater circuit can be varied based on
the surface
temperature level in a manner substantially similar to that described in
Figure 10 below.
For purposes of example, the temperature levels shown above in Table 2 can be
substituted for the dewpoint temperature levels provided in Figures 5-8 to
show example
variations that can be provided in the voltage level of the secondary heater
circuit of
Figure 4 based on differing electrical systems.
Figure 5 is a flowchart of another method for providing anti-sweat heating
control
with the dual-circuit anti-sweat heater control system of Figures 1-2B or 1A-B
and 3, in
accordance with one exemplary embodiment. Now referring to Figures 1-3 and 5,
the
exemplary method 500 begins at the START step and proceeds to step 505 where a
heater
control system for a display case door/window is provided. In one exemplary
embodiment, the heater control system is the unit 100 and system 200 or 300
described in
Figures 1-2B or 1A-B and 3. In step 510, the primary heater circuit 105 is
operated at a
constant power level. In one exemplary embodiment, the power level of the
primary
heater circuit 105 is set to the lowest amount that will output a level of
heat along the
small gauge wire of the circuit 105 to prevent condensation along the door
frame 103 and
the outer frame of the door 102 during normal conditions, such as those levels
that are less
than or less than or equal to the preset levels discussed in step 530 below.
For example, if
the ambient dewpoint temperature is normally 58 degrees Fahrenheit, the power
level or
the amount of power provided to the primary heater circuit 105 will be
adjusted to
maintain the temperature along the door frame 103 and the outer frame of the
door 102 at
a level above 58 degrees Fahrenheit. The primary heater circuit 105 is not
typically
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intended to be sufficient when ambient conditions dramatically differ from the
normal
level.
The ambient humidity level is received in step 515. In one exemplary
embodiment, the ambient humidity level is sensed by the sensor 120 and can be
transmitted, for example, to the controller or relay 125. In this exemplary
embodiment,
the sensor 120 is a dewpoint sensor that is capable of sensing both ambient
humidity and
temperature levels. An ambient temperature level is received from the sensor
120 at, for
example, the controller, in step 520. While the exemplary embodiment describes
both the
ambient temperature and humidity levels being sensed by a single sensor 120,
alternatively
two separate sensors may be used, one for temperature and one for humidity and
the
dewpoint temperature can be determined either by one of those two sensors or
by a
controller (not shown) electrically and/or communicably coupled to the
sensor(s) 120. In
step 525, the dewpoint temperature is calculated based on the received ambient
humidity
level and the received ambient temperature. In one exemplary embodiment, the
dewpoint
temperature is calculated by the dewpoint sensor 120. In an alternative
embodiment, the
dewpoint temperature is calculated by the controller.
In step 525 an inquiry is conducted to determine if the calculated dewpoint
temperature is greater than, or greater than or equal to, the preset dewpoint
temperature.
For example, in situations where the sensor 120 or relay 125 make the
determination, the
sensor 120 and/or relay 125, is set with a preset dewpoint temperature. When
the
dewpoint temperature, as calculated by the sensor 120, exceeds the preset
dewpoint
temperature, the secondary heater circuit 110 will be activated for a preset
amount or
percentage of time. In one exemplary embodiment, the preset dewpoint
temperature is 58
degrees Fahrenheit. Alternatively, the preset dewpoint temperature could be
set anywhere
between 40-80 degrees Fahrenheit. In an alternative embodiment, the
information from
the sensor 120 can be sent to a controller which determines if the calculated
dewpoint
temperature is greater than, or greater than or equal to, the preset dewpoint
temperature.
If the calculated dewpoint temperature is less than, or less than or equal to,
the
preset dewpoint temperature, the NO branch is followed back to step 515 to
continue
receiving ambient humidity and temperature level readings from the dewpoint
sensor 120.
On the other hand, if the calculated dewpoint temperature is greater than or
greater than or
equal to the preset dewpoint temperature, the YES branch is followed to step
535, where
relay 125 closes and power is supplied to the secondary heater circuit 110 for
a
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predetermined amount or percentage of time. In one exemplary embodiment, the
controller can send a signal to close the relay 125 based on the determination
made in step
530. In one exemplary embodiment, the amount or percentage of time that the
secondary
heater circuit 110 is activated is dependent on the calculated dewpoint
temperature from
the sensor 120. For example, if the preset dewpoint temperature is 58 degrees
Fahrenheit
and the calculated dewpoint temperature is 59 degrees Fahrenheit, the
secondary heater
circuit 110 is operated for forty percent of the time going forward, such as
by being on for
two minutes and then off for three minutes, or any other combination thereof
to satisfy the
percentage of time setting. As the calculated dewpoint temperature increases
further
above the preset dewpoint temperature, the percentage of time that the
secondary heater
circuit 110 is on is increased. For example the percentage of time that the
secondary
heater circuit 110 is on based on the calculated dewpoint temperature can
follow the
percentages shown in Table 3 below.
Calculated Dewpoint Temp. ( F) Percentage of Time Secondary Heater Circuit is
On
0-58 0%
59 40%
60 55%
61 70%
62 85%
63 and above 100%
TABLE 3
Table 3, provided above, is only one example of a preset dewpoint temperature
limit, the calculated dewpoint temperature levels and the amount that the
secondary heater
circuit 110 is operated based on the calculated dewpoint temperature and the
preset
dewpoint temperature limit. While the exemplary embodiment shown above
provides for
a linear increase in the percentage of time that the secondary heater is on,
the increase
could be non-linear in alternative exemplary embodiments. Further, the
increase in
percentage levels of on time could be spread out over a greater amount of
dewpoint
temperatures such that further step increases in percentage on time are
realized. In
addition, the dewpoint temperature for initial activation could be set at a
level that is
greater than or less than 58 degrees Fahrenheit provided for in the exemplary
embodiment.
As an additional option, in addition to or in the alternative to operating the
secondary
heater circuit 110 as described above, the operation of the primary heater
circuit 105 can
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be adjusted such that the primary heater circuit 105 can be turned on for the
preset amount
of time, instead of being on all of the time, depending on the dewpoint
temperature. This
optional arrangement would provide additional energy savings if needed or
desired. In
another alternative embodiment, once activated, the secondary heater circuit
110 remains
ON constantly until the calculated dewpoint temperature subsequently
determined is less
than, or less than or equal to, the preset dewpoint temperature.
In yet another alternative exemplary embodiment, instead of varying the amount
of
time the secondary heater circuit is activated based on the calculated
dewpoint
temperature, the voltage level supplied to the secondary heater circuit can be
varied based
on the calculated dewpoint temperature in a manner substantially similar to
that described
in Figure 10 below. For purposes of example, the calculated dewpoint
temperatures
shown above in Table 3 can be substituted for the calculated dewpoint
temperatures
provided in Figures 5-8 to show example variations that can be provided in the
voltage
level of the secondary heater circuit of Figure 5 based on differing
electrical systems.
In step 540, subsequent ambient humidity level and temperature readings are
received at the dewpoint sensor 120 and subsequent ambient dewpoint
temperatures are
calculated, for example either at the sensor 120 or the controller (not
shown). In step 545,
an inquiry is conducted to determine if the subsequent dewpoint temperature is
greater
than, or greater than or equal to, the preset dewpoint temperature. As with
step 530 above,
the determination can be made by the sensor 120, the relay 125 or a controller
(not
shown). If the subsequent dewpoint temperature is greater than, or greater
than or equal
to, the preset dewpoint temperature, the YES branch is followed back to step
540 to
continue receiving subsequent humidity level and temperature readings from the
sensor
120 and calculating subsequent dewpoint temperatures. Alternatively, if the
subsequent
ambient dewpoint temperature calculation is less than or less than or equal to
the preset
dewpoint temperature, the NO branch is followed to step 550. In step 550, the
relay 125
opens and the secondary heater circuit 110 is deactivated. In one exemplary
embodiment,
the controller can send a signal to open the relay 125 based on the
determination made in
step 545. In addition, optionally, if adjustments to the operation of the
primary heater
circuit 105 were made in a manner similar to that described in step 535, the
primary heater
circuit 105 can be adjusted to once again operate in its original operational
state (e.g.,
operating constantly at a constant power level). The process then returns to
step 515 to
receive the next ambient humidity level reading from the sensor 120.
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Figure 6 is a flowchart of another method for providing anti-sweat heating
control
with the dual-circuit anti-sweat heater control system of Figures 1-2B or 1A-B
and 3, in
accordance with one exemplary embodiment. Now referring to Figures 1-2B and 6
or 1A-
B, 3 and 6, the exemplary method 600 begins at the START step and proceeds to
step 605
where a heater control system for a display case door/window is provided. In
one
exemplary embodiment, the heater control system is the unit 100 and system 200
or 300
described in Figures 1-2B or 1A-B and 3. In step 610, the primary heater
circuit 105 is
operated at a constant power level. In one exemplary embodiment, the power
level of the
primary heater circuit 105 is set to the lowest amount that will output a
level of heat along
the small gauge wire of the circuit 105 to prevent condensation along the door
frame 103
and the outer frame of the door 102 during normal conditions, such as those
levels that are
less than or less than or equal to the present levels discussed in step 620
below. For
example, if the ambient dewpoint temperature is normally 58 degrees
Fahrenheit, the
power level or the amount of power provided to the primary heater circuit 105
will be
adjusted to maintain the temperature along the door frame 103 and the outer
frame of the
door 102 at a level above 58 degrees Fahrenheit. The primary heater circuit
105 is not
typically intended to be sufficient when ambient conditions dramatically
differ from the
normal level or variations in conditions from time-to-time.
The ambient humidity level is received in step 615. In one exemplary
embodiment, the ambient humidity level is sensed by the sensor 120 and can be
transmitted to, for example, a controller or relay 125. In this exemplary
embodiment, the
sensor 120 is a humidity sensor. In step 620, an inquiry is conducted to
determine if the
ambient humidity level is greater than, or greater than or equal to, a preset
humidity level.
For example, in situations where the sensor 120 or relay 125 make the
determination, the
sensor 120 or relay 125 can be set with a preset humidity level. When the
humidity level,
as sensed by the sensor 120, exceeds or equals (depending upon how it is set
up) the preset
humidity level, the secondary heater circuit 110 will be activated for a
preset amount or
percentage of time similar to that described in Figure 4. In an alternative
embodiment, the
information from the sensor 120 can be sent to a controller (not shown) which
determines
if the ambient humidity level is greater than, or great than or equal to, the
preset humidity
level.
If the ambient humidity level is less than, or less than or equal to, the
preset
humidity level, the NO branch is followed to step 625. In step 625, an inquiry
is conduct
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to determine if the ambient humidity level is less than, or less than or equal
to a second
preset humidity level. There may be situations where the ambient humidity
level,
temperature, or calculated dewpoint temperature are so low that it is not even
necessary to
operate the primary heater circuit 105 because the risk of condensation is
small or non-
existent. In one exemplary, the second preset humidity level is 0-30% relative
humidity.
Alternatively, the second preset humidity level could be anywhere between 0-
40% relative
humidity. As with step 620, the determination can be made by the sensor 120,
the relay
125, or a controller (not shown). If the ambient humidity level is not less
than, or less than
or equal to, the second present humidity level, the NO branch is followed back
to step 610
to continue operation of the primary heater circuit 105 at the constant power
level. On the
other hand, if the ambient humidity level is less than, or less than or equal
to, the second
preset humidity level, the YES branch is followed to step 630, where the
primary heater
circuit 105 is deactivated. While not shown in Figures 2A-B, a relay could
also be
electrically coupled between the sensor 120 and the primary heater circuit 105
or between
a different sensor and the primary heater circuit 105 to activate and
deactivate the primary
heater circuit 105. The process then returns to step 615 to continue to
receive ambient
humidity level readings.
Returning to step 620, if the ambient humidity level is greater than, or
greater than
or equal to, the present humidity level, the YES branch is followed to step
635, where
relay 125 closes and power is supplied to the secondary heater circuit 110 for
a
predetermined amount or percentage of time similar to the manner and options
described
in Figure 4 above. As an additional option, in addition to or in the
alternative to operating
the secondary heater circuit 110 as described above, the operation of the
primary heater
circuit 105 can be adjusted such that the primary heater circuit 105 can be
turned on for
the preset amount of time, instead of being on all of the time, depending on
the humidity
level. This optional arrangement would provide additional energy savings if
needed or
desired. In an alternative exemplary embodiment, instead of varying the amount
of time
the secondary heater circuit 110 is activated based on the ambient humidity
level, the
voltage level supplied to the secondary heater circuit can be varied based on
the ambient
humidity level in a manner substantially similar to that described in Figure
10 below. For
purposes of example, the ambient humidity levels shown above in Table 2
described
above with reference to Figure 4 can be substituted for the dewpoint
temperature levels
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provided in Figures 5-8 to show example variations that can be provided in the
voltage
level of the secondary heater circuit of Figure 6 based on differing
electrical systems.
In one exemplary embodiment, the controller can send a signal to close the
relay
125 based on the determination made in step 620. In step 640, subsequent
ambient
humidity level readings are received by the humidity sensor 120. In step 645,
an inquiry is
conducted to determine if the subsequent humidity level is greater than, or
greater than or
equal to, the preset humidity level. As with step 620 above, the determination
can be
made by the sensor 120, the relay 125, or a controller (not shown). If the
subsequent
humidity level is greater than, or greater than or equal to, the preset
humidity level, the
YES branch is followed back to step 640 to continue receiving subsequent
humidity level
readings at the sensor 120. Alternatively, if the subsequent ambient humidity
level
reading is less than, or less than or equal to, the preset humidity level, the
NO branch is
followed to step 650. In step 650, the relay 125 opens and the secondary
heater circuit 110
is deactivated. In one exemplary embodiment, the controller can send a signal
to open the
relay 125 based on the determination made in step 645. In addition,
optionally, if
adjustments to the operation of the primary heater circuit 105 were made in a
manner
similar to that described in step 635, the primary heater circuit 105 can be
adjusted to once
again operate in its original operational state (e.g., operating constantly at
a constant
power level). The process then returns to step 615 to receive the next ambient
humidity
level reading at the humidity sensor 120.
While the exemplary embodiment of Figure 6 has been described with reference
to
a humidity sensor and humidity levels, in an alternative embodiment, the
method of Figure
6 could be modified to activate and deactivate the primary 105 and secondary
110 heater
circuits based on ambient temperature readings from a temperature sensor 120
as
compared to a preset temperature similar to that described in Figure 4 or
based on
calculated dewpoint temperature as compared to a preset dewpoint temperature
similar to
that described in Figure 5. In one exemplary embodiment, the second preset
temperature
could be between 0-40 degrees Fahrenheit, while the second preset dewpoint
temperature
could be between 32-50 degrees Fahrenheit.
Figure 7 is a flowchart of another method for providing anti-sweat heating
control
with the dual-circuit anti-sweat heater control system of Figures 1-2B or 1A-B
and 3, in
accordance with one exemplary embodiment. Now referring to Figures 1-2B and 7
or 1A-
B, 3, and 7, the exemplary method 700 begins at the START step and proceeds to
step 705
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where a heater control system for a display case door/window is provided. In
one
exemplary embodiment, the heater control system is the unit 100 described in
Figures 1A-
B employing the circuit system 300 of Figure 3 or the system 200 of Figures 2A-
B. In
step 710, the primary heater circuit 105 is operated at a constant power
level. Step 710 is
optional and is employed if there are two heating circuits in the system. In
one exemplary
embodiment, the power level of the primary heater circuit 105 is set to the
lowest amount
that will output a level of heat along the small gauge wire of the circuit 105
to prevent
condensation along the door frame 103 and the outer frame of the door 102
during normal
conditions. For example, if the ambient dewpoint temperature is normally 58
degrees
Fahrenheit, the power level or the amount of power provided to the primary
heater circuit
105 will be adjusted to maintain the temperature along the door frame 103 and
the outer
frame of the door 102 at a level above 58 degrees Fahrenheit. The primary
heater circuit
105 is not typically intended to be sufficient when ambient conditions
dramatically differ
from the normal level or variations in conditions from time-to-time.
Surface temperature readings are received from one or multiple temperature
sensors 335 and transmitted to the controller 330 in step 715. In one
exemplary
embodiment, each temperature sensor 335 transmits the sensed temperature
readings to the
controller 330 via one or more temperature sensor contacts 340. In one
exemplary
embodiment, three separate temperature sensors are positioned along an outer
surface of
the door frame 103. Alternatively greater or fewer numbers of temperature
sensors may
be used in step 715. In step 720, the controller 330 evaluates the readings
from the
multiple temperature sensors 335 and determines the lowest received surface
temperature
reading received in that iteration from the temperature sensors 335.
The ambient humidity level is received at the controller 330 in step 725 from
the
sensor 320. In this exemplary embodiment, the sensor 320 is a dewpoint sensor.
An
ambient temperature level is received by the controller 330 from the sensor
320 in step
730. While the exemplary embodiment describes both the ambient temperature and
humidity levels being sensed by a single sensor 320, alternatively two
separate sensors
may be used, one for temperature and one for humidity and the dewpoint
temperature can
be determined either by one of those two sensors or by the controller 330. In
step 735, the
dewpoint temperature is calculated based on the received ambient humidity
level and the
received ambient temperature. In one exemplary embodiment, the dewpoint
temperature
is calculated by the dewpoint sensor 320 and transmitted to the controller
330.
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Alternatively, the dewpoint temperature is calculated by the controller 330.
In step 740,
the controller 330 compares the lowest surface temperature reading to the
calculated
dewpoint temperature.
In step 745 an inquiry is conducted to determine if the lowest surface
temperature
reading is less than, or less than or equal to, the calculated dewpoint
temperature. For
example, when the lowest surface temperature reading is less than, or less
than or equal to
the calculated dewpoint temperature, the heater circuit 310 will be activated
for a preset
amount or percentage of time similar to that described in Figure 5.
If the lowest surface temperature reading is greater than, or greater than or
equal
to, the calculated dewpoint temperature, the NO branch is followed back to
step 715 to
continue receiving surface temperature readings from the one or multiple
sensors 335. On
the other hand, if the lowest surface temperature reading is less than, or
less than or equal
to, the calculated dewpoint temperature, the YES branch is followed to step
750, where
relay 325 closes and power is supplied to the heater circuit 310 for a
predetermined
amount or percentage of time. In one exemplary embodiment, the controller can
send a
signal to close the relay 125 based on the determination made in step 745. In
one
exemplary embodiment, the amount or percentage of time that the heater circuit
310 is
activated is dependent on the amount of difference between the lowest surface
temperature
reading from the sensors 335 and the calculated dewpoint temperature. For
example the
percentage of time that the heater circuit 310 is on can be similar to that
shown in Table 4
below.
Difference Between Temperature
Sensor and Calculated Dewpoint Percentage of Time Secondary Heater Circuit is
On
Temperature (in F)
0 0%
1 40%
2 55%
3 70%
4 85%
5 and above 100%
TABLE 4
Table 4, provided above, is only one example. While the exemplary embodiment
shown above provides for a linear increase in the percentage of time that the
heater circuit
310 is on, the increase could be non-linear in alternative exemplary
embodiments.
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Further, the increase in percentage levels of on time could be spread out over
a greater
amount of differences between the surface temperature sensor(s) 335 and the
calculated
dewpoint temperature such that further step increases in percentage on time
are realized.
In addition, the initial difference for initial activation of the heater
circuit 310 could be set
at a level that is greater than or less than 1 degree Fahrenheit of difference
provided for in
the exemplary embodiment. As an additional option, in addition to or in the
alternative to
operating the secondary heater circuit 110 as described above, the operation
of the primary
heater circuit 105 can be adjusted such that the primary heater circuit 105
can be turned on
for the preset amount of time, instead of being on all of the time, depending
on the
dewpoint temperature. This optional arrangement would provide additional
energy
savings if needed or desired.In another alternative embodiment, once
activated, the heater
circuit 310 remains ON constantly until the difference is subsequently
determined is less
than, or less than or equal to, one.
In yet another alternative exemplary embodiment, instead of varying the amount
of
time the heater circuit 310 is activated based on the temperature difference,
the voltage
level supplied to the heater circuit 310 can be varied based on the
temperature difference
in a manner substantially similar to that described in Figure 10 below. For
purposes of
example, the temperature differences shown above in Table 4 can be substituted
for the
calculated dewpoint temperatures provided in Figures 5-8 to show example
variations that
can be provided in the voltage level of the heater circuit 310 of Figure 7
based on differing
electrical systems.
Subsequent surface temperature readings are received from the sensors 335 and
transmitted to the controller 330 in step 755. In step 760, the controller 330
determines
the lowest surface temperature of the subsequently received surface
temperature readings.
In step 765, the controller 330 calculates a subsequent dewpoint temperature
based on
subsequent humidity and temperature readings received from the sensor 320 and
transmitted to the controller 330. The controller 330 compares the subsequent
lowest
surface temperature reading to the subsequent dewpoint temperature in step
770. In step
775, an inquiry is conducted to determine if the lowest subsequent surface
temperature
reading is less than, or less than or equal to, the subsequent dewpoint
temperature. If so,
the YES branch is followed back up to step 755 to continue receiving
subsequent surface
temperature readings from the temperature sensors 335. Otherwise, the NO
branch is
followed to step 780, where the controller 330 transmits a signal to open the
relay 325 and
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deactivate the heater circuit 310. In addition, optionally, if adjustments to
the operation of
the primary heater circuit 105 were made in a manner similar to that described
in step 750,
the primary heater circuit 105 can be adjusted to once again operate in its
original
operational state (e.g., operating constantly at a constant power level). The
process then
continues to step 715 to continue receiving surface temperature readings from
the one or
more temperature sensors 335.
During any of the steps provided in Figure 7, the surface temperatures, the
calculated dewpoints and the time (either by percentage, total amount) that
the circuit 310
is activated can be recorded and stored in the data storage device 345. In
addition, while
the controller 330 is operating, information that is currently being received
by the
controller 300 and/or data stored in the data storage device 345 can be
wirelessly or wire
transmitted to another device, such as another computer by way of the remote
monitoring
device 355.
The methods shown and described in Figures 4-7 may be carried out or performed
in any suitable order as desired in various alternative exemplary embodiments.
Additionally, in certain exemplary embodiments, at least a portion of the
steps may be
carried out in parallel. Furthermore, in certain exemplary embodiments, one or
more steps
may be omitted.
Accordingly, the exemplary embodiments described herein provide the technical
effects of creating a system, method, and apparatus that provides real-time,
single or dual-
circuit anti-sweat control for refrigerated display cases. Various block
and/or flow
diagrams of systems, methods, apparatus, and/or computer program products
according to
exemplary embodiments are described above. It will be understood that one or
more
elements of the schematic diagrams or steps in the flowcharts can be
implemented by
computer-executable program instructions. Likewise, some elements of the
schematic
diagrams and steps of the flowchart diagrams may not necessarily need to be
performed in
the order presented, or may not necessarily need to be performed at all,
according to
certain alternative embodiments.
These computer-executable program instructions may be loaded onto a special
purpose computer or other particular machine, a processor, or other
programmable data
processing apparatus, such as the controller, to produce a particular machine,
such that the
instructions that execute on the computer, processor, or other programmable
data
processing apparatus create means for implementing one or more functions
specified in
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the flowcharts. These computer program instructions may also be stored in a
computer-
readable memory, such as the data storage device 345 on or communicably
coupled to the
controller, that can direct a computer or other programmable data processing
apparatus to
function in a particular manner, such that the instructions stored in the
computer-readable
memory produce an article of manufacture including instruction means that
implement one
or more functions specified in the flow diagram block or blocks. As an
example,
embodiments of the invention may provide for a computer program product,
comprising a
computer usable medium having a computer readable program code or program
instructions embodied therein, said computer readable program code adapted to
be
executed to implement one or more functions specified in the flowcharts of
Figures 4-7.
The computer program instructions may also be loaded onto a computer or other
programmable data processing apparatus, such as the controller, to cause a
series of
operational elements or steps to be performed on the computer or other
programmable
apparatus to produce a computer-implemented process such that the instructions
that
execute on the computer or other programmable apparatus provide elements or
steps for
implementing the functions specified in the steps of Figures 4-7.
Figures 8 and 9 are perspective view of two additional example refrigerated
display units configured to include the dual-circuit or single circuit anti-
sweat heater
control system 200, 300 and/or a smart controller system 200, 300 and capable
of
controlling condensation using the exemplary methods described in Figures 4-7
in
accordance with one exemplary embodiment. Referring now to Figure 8, the
exemplary
refrigerated display unit 800 can include a casing 815 which includes multiple
side walls
820 and a bottom wall or floor (not shown). The exemplary display unit 800 can
have an
opening 825 along the top defined by the side walls 820 for providing access
into the
casing or cavity 830 of the unit 800. Further, the side walls 820 and the
bottom wall can
define one or more cavities 830 for storing products within the unit 800 for
access through
the top opening 825. The unit 800 can also include one or more cooling units
(not shown)
for cooling the cavity area 830.
The side walls 820 can include one or more transparent panels 835. One or more
of the transparent panels 835 can also include or be attached to a metallic
frame 805, 810.
The metallic frame 805, 810 can be made of a metallic material, such as steel
or
aluminum. The metallic frame 805, 810 itself, or an area about the transparent
material,
such as glass or transparent plastic can include a primary heater circuit
and/or a secondary
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heater circuit as shown and described in Figures 2A-B and 3 to transfer heat
or to heat up
the metallic frame 805, 810 or transparent side walls 835 to limit or prevent
condensation
by way of thermal conduction.
Similarly, Figure 9 presents another refrigerated display unit 900 or a
portion of
the display unit that can be used in conjunction with the unit 800 of Figure 8
in accordance
with one exemplary embodiment. Referring now to Figure 9, the exemplary unit
900 can
include a casing which includes multiple side walls 915 and a bottom wall or
floor 910.
The exemplary display unit 900 can have an opening 920 along the top defined
by the side
walls for providing access into the casing or cavity of the unit 900. Further,
the side walls
and the bottom wall can define one or more cavities for storing products
within the unit
900 for access through the top opening 920. The unit 900 can also include one
or more
cooling units 925 for cooling the cavity area and a metallic area 905 disposed
near the
cooling unit and providing or acting as part of one of the side walls or the
top of one of the
side walls. This large metallic area 905 can be a source of condensation if
not properly
controlled. The metallic area 905 can include a primary heater circuit and/or
a secondary
heater circuit as shown and described in Figures 2A-B and 3 to transfer heat
or to heat up
the metallic area 905 to limit or prevent condensation by way of thermal
conduction.
Figure 10 is a flowchart of another method for providing anti-sweat heating
control
with the dual-circuit anti-sweat heater control system of Figures 1-2B or 1A-B
and 3, or
through the use of a single-circuit anti-sweat heater control system in
accordance with one
exemplary embodiment. Now referring to Figures 1-3 and 10, the exemplary
method 1000
begins at the START step and proceeds to step 1005 where a heater control
system for a
display case door/window is provided. In one exemplary embodiment, the heater
control
system is the unit 100 and system 200 or 300 described in Figures 1-2B or 1A-B
and 3. In
step 1010, the primary heater circuit 105, if a dual heater circuit system is
being employed,
is operated at a constant power level. In one exemplary embodiment, the power
level of
the primary heater circuit 105 is set to the lowest amount that will output a
level of heat
along the small gauge wire of the circuit 105 to prevent condensation along
the door frame
103 and the outer frame of the door 102 during normal conditions, such as
those levels that
are less than or less than or equal to the preset levels discussed in step
1030 below. For
example, if the ambient dewpoint temperature is normally 58 degrees
Fahrenheit, the
power level or the amount of power provided to the primary heater circuit 105
will be
adjusted to maintain the temperature along the door frame 103 and the outer
frame of the
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door 102 at a level above 58 degrees Fahrenheit. The primary heater circuit
105 is not
typically intended to be sufficient when ambient conditions dramatically
differ from the
normal level.
The ambient humidity level is received in step 1015. In one exemplary
embodiment, the ambient humidity level is sensed by the sensor 120 and can be
transmitted, for example, to the controller or relay 125. In this exemplary
embodiment,
the sensor 120 is a dewpoint sensor that is capable of sensing both ambient
humidity and
temperature levels. An ambient temperature level is received from the sensor
120 at, for
example, the controller, in step 1020. While the exemplary embodiment
describes both
the ambient temperature and humidity levels being sensed by a single sensor
120,
alternatively two separate sensors may be used, one for temperature and one
for humidity
and the dewpoint temperature can be determined either by one of those two
sensors or by a
controller (not shown) electrically and/or communicably coupled to the
sensor(s) 120. In
step 1025, the dewpoint temperature is calculated based on the received
ambient humidity
level and the received ambient temperature. In one exemplary embodiment, the
dewpoint
temperature is calculated by the dewpoint sensor 120. In an alternative
embodiment, the
dewpoint temperature is calculated by the controller.
In step 1030 an inquiry is conducted to determine if the calculated dewpoint
temperature is greater than, or greater than or equal to, the preset dewpoint
temperature.
For example, in situations where the sensor 120 or relay 125 make the
determination, the
sensor 120 and/or relay 125, is set with a preset dewpoint temperature. When
the
dewpoint temperature, as calculated by the sensor 120, exceeds the preset
dewpoint
temperature, the secondary heater circuit 110 will be activated at one of a
set of preset
stepped voltage levels, which can be at a series of steps below the full
voltage level for the
circuit. In one exemplary embodiment, the preset dewpoint temperature is 58
degrees
Fahrenheit. Alternatively, the preset dewpoint temperature could be set
anywhere between
40-80 degrees Fahrenheit. In an alternative embodiment, the information from
the sensor
120 can be sent to a controller which determines if the calculated dewpoint
temperature is
greater than, or greater than or equal to, the preset dewpoint temperature.
If the calculated dewpoint temperature is less than, or less than or equal to,
the
preset dewpoint temperature, the NO branch is followed back to step 1015 to
continue
receiving ambient humidity and temperature level readings from the dewpoint,
or other,
sensor 120. On the other hand, if the calculated dewpoint temperature is
greater than or
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greater than or equal to the preset dewpoint temperature, the YES branch is
followed to
step 1040, where a determination is made as to the voltage level setting for
the secondary
heater based at least upon the amount that the dewpoint temperature is above
the preset
dewpoint temperature. For example, the system, (i.e. the relay or controller)
can be set up
with a series or preset stepped voltage levels that would be applied/supplied
to the
secondary heater circuit 110 (or the primary heater circuit in a single heater
circuit
arrangement) based on the calculated dewpoint temperature. In one exemplary
embodiment, the determination as to the amount of voltage supplied to or
driving the
secondary heater circuit 110 is dependent on the calculated dewpoint
temperature from the
sensor 120. For example, if the preset dewpoint temperature is 58 degrees
Fahrenheit and
the calculated dewpoint temperature is 59 degrees Fahrenheit, the controller
can
determine that the secondary heater circuit 110 is to be supplied with 50
Volts of
electricity. As the calculated dewpoint temperature increases further above
the preset
dewpoint temperature, the controller may determine, based on preset values or
percentages, to increase the voltage level to be supplied to the secondary
heater circuit
110. For example the controller's determination as to the voltage level to be
supplied to
the secondary heater circuit 110 based on the calculated dewpoint temperature
can follow
the voltage levels shown in Table 5 below.
Calculated Dewpoint Temp. ( F) Percentage of Time Secondary Heater Circuit is
On
0-58 0 Volts
59 50 Volts
60 70 Volts
61 95 Volts
62 105 Volts
63 and above 120 Volts
TABLE 5
Table 5, provided above, is only one example of a preset dewpoint temperature
limit, the calculated dewpoint temperature levels and the voltage levels
provided to the
secondary heater circuit 110 based on the calculated dewpoint temperature and
the preset
dewpoint temperature limit. While the exemplary embodiment shown above
provides for
a generally linear increase in the amount of voltage provided to drive the
secondary heater
circuit, the increase could be non-linear in alternative exemplary
embodiments. Further,
the increase in voltage levels could be spread out over a greater amount of
dewpoint
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temperatures such that further step increases in voltage levels are realized.
In addition, the
dewpoint temperature for initial activation could be set at a level that is
greater than or less
than 58 degrees Fahrenheit provided for in the exemplary embodiment.
Furthermore,
while the exemplary table presented above is based on an electrical system
where 120
volts is the full voltage level, the exemplary system and method can be
modified to work
with other types of electrical systems as well, where full voltage level is
other than 120
volts. This includes systems where the full voltage level is 230 volts, 240
volts and/or 400
volts. Examples tables for each might look like that provided below in Tables
6-8.
230 Volt Electrical System
Calculated Dewpoint Temp. ( F) Percentage of Time Secondary Heater Circuit is
On
0-58 0 Volts
59 110 Volts
60 140 Volts
61 170 Volts
62 200 Volts
63 and above 230 Volts
TABLE 6
240 Volt Electrical System
Calculated Dewpoint Temp. ( F) Percentage of Time Secondary Heater Circuit is
On
0-58 0 Volts
59 120 Volts
60 150 Volts
61 180 Volts
62 210 Volts
63 and above 240 Volts
TABLE 7
400 Volt Electrical System
Calculated Dewpoint Temp. ( F) Percentage of Time Secondary Heater Circuit is
On
0-58 0 Volts
59 200 Volts
60 250 Volts
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61 300 Volts
62 350 Volts
63 and above 400 Volts
TABLE 8
As an additional option, in addition to or in the alternative to operating the
secondary heater circuit 110 as described above, the operation of the primary
heater circuit
105 can be adjusted such that the voltage level of the primary heater circuit
105 can be
adjusted, instead of being on at full voltage level all of the time, depending
on the
dewpoint temperature. This optional arrangement would provide additional
energy
savings if needed or desired. In step 1045, the secondary heater circuit 110
(or the
primary heater circuit in a single heater circuit embodiment) is supplied with
the amount
of voltage corresponding with the preset voltage level setting based on the
calculated
dewpoint temperature or the amount that the calculated dewpoint temperature is
above the
preset dewpoint temperature. For example, relay 125 closes and power is
supplied to the
secondary heater circuit 110 at one of a set of preset stepped voltage levels,
like those
shown in Table 5. In one exemplary embodiment, the controller can send a
signal to close
the relay 125 and provide the secondary heater circuit with the amount of
voltage
corresponding to the preset voltage level setting based on the determination
made in step
1040. In the exemplary embodiment provided above, once activated, the
secondary heater
circuit 110 remains ON constantly at the particular preset voltage level until
the calculated
dewpoint temperature subsequently determined is less than, or less than or
equal to, the
preset dewpoint temperature or the calculated dewpoint temperature changes to
one that is
greater than or greater than or equal to the preset dewpoint temperature but
is different
than that of the current calculated dewpoint temperature.
In step 1050, subsequent ambient humidity level readings are received at the
sensor
120. Subsequent ambient temperature level readings are received at the sensor
120 in step
1055. In step 1060, a subsequent dewpoint temperature is calculated, for
example either at
the sensor 120 or the controller (not shown), based on the subsequent ambient
humidity
and temperature level readings received in steps 1050 and 1055, in a manner
substantially
the same as that discussed with regard to step 1025. In step 1065, an inquiry
is conducted
to determine if the subsequent calculated dewpoint temperature is greater
than, or greater
than or equal to, the preset dewpoint temperature. As with step 1030 above,
the
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determination can be made by the sensor 120, the relay 125 or a controller
(not shown). If
the subsequent calculated dewpoint temperature is greater than, or greater
than or equal to,
the preset dewpoint temperature, the YES branch is followed back to step 1040
to continue
determining the amount of voltage to provide to the secondary heater circuit
and to
continue receiving subsequent humidity level and temperature readings from the
sensor
120 and calculating subsequent dewpoint temperatures. Alternatively, if the
subsequent
calculated dewpoint temperature is less than or less than or equal to the
preset dewpoint
temperature, the NO branch is followed to step 1070. In step 1070, the relay
125 opens
and the secondary heater circuit 110 is deactivated. In one exemplary
embodiment, the
controller can send a signal to open the relay 125 based on the determination
made in step
1065. In addition, optionally, if adjustments to the operation of the primary
heater circuit
105 were made in a manner similar to that described in step 1045, the primary
heater
circuit 105 can be adjusted to once again operate in its original operational
state (e.g.,
operating constantly at a constant full voltage level or could alternatively
remain at the
reduced voltage level). The process then returns to step 1015 to receive the
next ambient
humidity level reading from the sensor 120.
Although example embodiments of the disclosure have been described, one of
ordinary skill in the art will recognize that numerous other modifications and
alternative
embodiments are within the scope of the disclosure. For example, any of the
functionality
and/or processing capabilities described with respect to a particular device
or component
may be performed by any other device or component. Furthermore, while various
example implementations and architectures have been described in accordance
with
example embodiments of the disclosure, one of ordinary skill in the art will
appreciate that
numerous other modifications to the example implementations and architectures
described
herein are also within the scope of this disclosure.
Certain aspects of the disclosure are described above with reference to block
and flow
diagrams of systems, methods, apparatuses, and/or computer program products
according
to example embodiments. It will be understood that one or more blocks of the
block
diagrams and steps of the flow diagrams, and combinations of blocks in the
block
diagrams and steps of the flow diagrams, respectively, may be implemented by
execution
of computer-executable program instructions. Likewise, some blocks of the
block
diagrams and steps of the flow diagrams may not necessarily need to be
performed in the
order presented, or may not necessarily need to be performed at all, according
to some
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embodiments. Further, additional components and/or operations beyond those
depicted in
blocks of the block and/or steps of the flow diagrams may be present in
certain
embodiments.
Accordingly, blocks of the block diagrams and steps of the flow diagrams
support
combinations of means for performing the specified functions, combinations of
elements
or steps for performing the specified functions and program instruction means
for
performing the specified functions. It will also be understood that each block
of the block
diagrams and step of the flow diagrams, and combinations of blocks in the
block diagrams
and steps of the flow diagrams, may be implemented by controllers or special-
purpose,
hardware-based computer systems that perform the specified functions, elements
or steps,
or combinations of special-purpose hardware and computer instructions.
Computer-executable program instructions may be loaded onto a controller or
other special-purpose computer or other particular machine, a processor, or
other
programmable data processing apparatus to produce a particular machine, such
that
execution of the instructions on the computer, processor, or other
programmable data
processing apparatus causes one or more functions or steps specified in the
flow diagrams
to be performed. These computer program instructions may also be stored in a
computer-
readable storage medium (CRSM) that upon execution may direct a computer or
other
programmable data processing apparatus to function in a particular manner,
such that the
instructions stored in the computer-readable storage medium implement one or
more
functions or steps specified in the flow diagrams. The computer program
instructions may
also be loaded onto a computer or other programmable data processing apparatus
to cause
a series of operational elements or steps to be performed on the computer or
other
programmable apparatus to produce a computer-implemented process.
Additional types of CRSM that may be present in any of the devices described
herein may include, but are not limited to, programmable random access memory
(PRAM), SRAM, DRAM, RAM, ROM, electrically erasable programmable read-only
memory (EEPROM), flash memory or other memory technology, compact disc read-
only
memory (CD-ROM), digital versatile disc (DVD) or other optical storage,
magnetic
cassettes, magnetic tape, magnetic disk storage or other magnetic storage
devices, or any
other medium which can be used to store the information and which can be
accessed.
Combinations of any of the above are also included within the scope of CRSM.
Alternatively, computer-readable communication media (CRCM) may include
computer-
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readable instructions, program modules, or other data transmitted within a
data signal,
such as a carrier wave, or other transmission. However, as used herein, CRSM
does not
include CRCM.
Although example embodiments have been described in language specific to
structural features and/or methodological acts, it is to be understood that
the disclosure is
not necessarily limited to the specific features or acts described. Rather,
the specific
features and acts are disclosed as illustrative forms of implementing the
example
embodiments. Conditional language, such as, among others, "can," "could,"
"might," or
"may," unless specifically stated otherwise, or otherwise understood within
the context as
used, is generally intended to convey that certain example embodiments could
include,
while other example embodiments do not include, certain features, elements,
and/or steps.
Thus, such conditional language is not generally intended to imply that
features, elements,
and/or steps are in any way required for one or more embodiments or that one
or more
embodiments necessarily include logic for deciding, with or without user input
or
prompting, whether these features, elements, and/or steps are included or are
to be
performed in any particular embodiment.
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