SYSTEMS, METHODS, AND APPARATUS FOR PREVENTING CONDENSATION IN REFRIGERATED DISPLAY CASES

Info

Publication number: 20140069125
Type: Application
Filed: Sep 12, 2013
Publication Date: Mar 13, 2014
Applicant: HEATCRAFT REFRIGERATION PRODUCTS LLC (Richardson, TX)
Inventors: Chandrashekhara S. Chikkakalbalu (Columbus, GA), Ajay Iyengar (Stone Mountain, GA)
Application Number: 14/024,967

Abstract

Systems, methods, and apparatuses are provided for preventing condensation in refrigerated display cases. A display case can be provided with one or more heater circuits and one or more sensors communicably coupled thereto. The sensor can sense ambient humidity levels, ambient temperature levels, and surface temperature levels. In certain embodiments, dewpoint temperatures may be calculated based on the ambient humidity and temperature levels provided by the sensor. The sensed ambient humidity level, temperature level, surface temperature, or calculated dewpoint can be compared to preset trigger levels and at least one of the heater circuits can be activated if the preset trigger level is violated. Activation of the heater circuit can be for a predetermined amount or percentage of time or at a predetermined voltage level based on the sensed or calculated level or the amount the sensed or calculated level is over the preset trigger level.

Description

Description

RELATED APPLICATION

This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 61/700,303, titled Systems, Methods, and Apparatus for Preventing Condensation in Display Cases, filed on Sep. 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 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:

FIG. 1A 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;

FIG. 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;

FIGS. 2A and 2B are schematic diagrams of the dual-circuit anti-sweat heater control system for use in the refrigerated display unit of FIG. 1A in accordance with one exemplary embodiment;

FIG. 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 FIG. 1A in accordance with an alternate exemplary embodiment;

FIG. 4 is a flowchart of a method for providing anti-sweat heating control with the dual-circuit anti-sweat heater control system of FIGS. 2A-B in accordance with one exemplary embodiment;

FIG. 5 is a flowchart of another method for providing anti-sweat heating control with the dual-circuit anti-sweat heater control system of FIGS. 2A-B in accordance with another exemplary embodiment;

FIG. 6 is a flowchart of another method for providing anti-sweat heating control with the dual-circuit anti-sweat heater control system of FIGS. 2A-B in accordance with yet another exemplary embodiment;

FIG. 7 is a flowchart of a method for providing anti-sweat heating control with the anti-sweat heater control system of FIG. 3 in accordance with one exemplary embodiment;

FIG. 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;

FIG. 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

FIG. 10 is a flowchart of another method for providing anti-sweat heating control with the dual-circuit anti-sweat heater control system of FIGS. 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.

FIG. 1A 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. FIG. 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 FIGS. 1A and 1B, the exemplary display unit 100 can 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 FIG. 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 FIG. 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 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.

FIGS. 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 FIGS. 1A-1B. Now referring to FIGS. 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 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 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 FIGS. 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.

FIG. 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 FIG. 1A. Now referring to FIGS. 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 FIG. 1A 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 FIG. 1B. In one exemplary embodiment, the heater circuit 310 is substantially similar to the secondary heater circuit 110 of FIG. 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 FIG. 3 presents a single heater circuit 310, alternatively, two heater circuits similar to that shown and described with reference to FIGS. 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 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 FIGS. 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 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 FIG. 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.

FIG. 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 FIGS. 1-2B or 1A-B and 3, in accordance with one exemplary embodiment. Referring now to FIGS. 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 FIGS. 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 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 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.

TABLE 1 Percentage of Time Ambient Humidity Level Secondary Heater Circuit is On 0-55% 0% 56% 40% 57% 55% 58% 70% 59% 85% 60-100% 100%

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 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 FIG. 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 FIGS. 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 FIG. 4 has been described with reference to a humidity sensor and humidity levels, in an alternative embodiment, the method of FIG. 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 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.

TABLE 2 Percentage of Time Degrees Fahrenheit Secondary Heater Circuit is On 0-58 0% 59 40% 60 55% 61 70% 62 85% 63 and above 100%

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 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 FIG. 10 below. For purposes of example, the temperature levels shown above in Table 2 can be substituted for the dewpoint temperature levels provided in FIGS. 5-8 to show example variations that can be provided in the voltage level of the secondary heater circuit of FIG. 4 based on differing electrical systems.

FIG. 5 is a flowchart of another method for providing anti-sweat heating control with the dual-circuit anti-sweat heater control system of FIGS. 1-2B or 1A-B and 3, in accordance with one exemplary embodiment. Now referring to FIGS. 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 FIGS. 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 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 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.

TABLE 3 Calculated Percentage of Time Secondary Dewpoint Temp. (° F.) Heater Circuit is On 0-58 0% 59 40% 60 55% 61 70% 62 85% 63 and above 100%

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 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 FIG. 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 FIGS. 5-8 to show example variations that can be provided in the voltage level of the secondary heater circuit of FIG. 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.

FIG. 6 is a flowchart of another method for providing anti-sweat heating control with the dual-circuit anti-sweat heater control system of FIGS. 1-2B or 1A-B and 3, in accordance with one exemplary embodiment. Now referring to FIGS. 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 FIGS. 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 FIG. 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 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 FIGS. 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 FIG. 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 FIG. 10 below. For purposes of example, the ambient humidity levels shown above in Table 2 described above with reference to FIG. 4 can be substituted for the dewpoint temperature levels provided in FIGS. 5-8 to show example variations that can be provided in the voltage level of the secondary heater circuit of FIG. 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 FIG. 6 has been described with reference to a humidity sensor and humidity levels, in an alternative embodiment, the method of FIG. 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 FIG. 4 or based on calculated dewpoint temperature as compared to a preset dewpoint temperature similar to that described in FIG. 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.

FIG. 7 is a flowchart of another method for providing anti-sweat heating control with the dual-circuit anti-sweat heater control system of FIGS. 1-2B or 1A-B and 3, in accordance with one exemplary embodiment. Now referring to FIGS. 1-2B and 7 or 1A-B, 3, and 7, the exemplary method 700 begins at the START step and proceeds to step 705 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 FIGS. 1A-B employing the circuit system 300 of FIG. 3 or the system 200 of FIGS. 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. 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 FIG. 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.

TABLE 4 Difference Between Temperature Percentage of Sensor and Calculated Dewpoint Time Secondary Temperature (in ° F.) Heater Circuit is On 0 0% 1 40% 2 55% 3 70% 4 85% 5 and above 100%

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. 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 FIG. 10 below. For purposes of example, the temperature differences shown above in Table 4 can be substituted for the calculated dewpoint temperatures provided in FIGS. 5-8 to show example variations that can be provided in the voltage level of the heater circuit 310 of FIG. 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 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 FIG. 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 FIGS. 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 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 FIGS. 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 FIGS. 4-7.

FIGS. 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 FIGS. 4-7 in accordance with one exemplary embodiment. Referring now to FIG. 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 heater circuit as shown and described in FIGS. 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, FIG. 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 FIG. 8 in accordance with one exemplary embodiment. Referring now to FIG. 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 FIGS. 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.

FIG. 10 is a flowchart of another method for providing anti-sweat heating control with the dual-circuit anti-sweat heater control system of FIGS. 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 FIGS. 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 FIGS. 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 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 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.

TABLE 5 Calculated Dewpoint Percentage of Time Secondary Temp. (° F.) 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, 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 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

TABLE 6 Calculated Percentage of Time Dewpoint Temp. (° F.) 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

240 Volt Electrical System

TABLE 7 Calculated Percentage of Time Dewpoint Temp. (° F.) 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

400 Volt Electrical System

TABLE 8 Calculated Percentage of Time Dewpoint Temp. (° F.) Secondary Heater Circuit is On 0-58 0 Volts 59 200 Volts 60 250 Volts 61 300 Volts 62 350 Volts 63 and above 400 Volts

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 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 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-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.

Claims

1. A method for controlling a heating system in a refrigerated display case comprising the steps of:

providing a refrigerated display case comprising a secondary heater circuit and a sensor communicably coupled to the secondary heater circuit;

receiving an ambient humidity level from the sensor;

determining if the ambient humidity level is greater than a preset humidity level; and

activating the secondary heater circuit based on the determination that the ambient humidity level is greater than the preset humidity level.

2. The method of claim 1, further comprising the steps of:

providing a primary heater circuit for the refrigerated display case; and

operating the primary heater circuit at a constant power level.

3. The method of claim 2, wherein the refrigerated display case comprises:

a plurality of walls defining at least one cavity;

an aperture disposed though a first of the plurality of the walls to provide access to the cavity; and

a door comprising a door frame along the first wall and disposed about at least a portion of the aperture,

wherein at least a portion of the primary heater circuit and the secondary heater circuit are disposed within the door frame.

4. The method of claim 2, wherein the refrigerated display case comprises:

a plurality of side walls, and a floor coupled to one or more of the side walls;

said side walls and floor defining a cavity within the display case, wherein at least one of the side walls include a portion that is at least partially transparent and wherein at least one other of the side walls includes a top portion comprising a metallic panel;

said side walls defining an opening along a top of the side walls to access the cavity from an area above the side walls;

wherein the at least one of the side walls comprises a metallic panel and wherein the primary heater circuit and the secondary heater circuit are in thermal communication with at least a portion of the metallic panel, said primary heater circuit being electrically isolated from said secondary heater circuit.

5. The method of claim 1, wherein activating the secondary heater circuit comprises activating the secondary heater circuit for a predetermined amount of time, wherein the predetermined amount of time the secondary heater circuit is activated is based on the ambient humidity level.

6. The method of claim 5, wherein the predetermined amount of time the secondary heater circuit is activated increases as the ambient humidity level from the sensor increases.

7. The method of claim 1, further comprises the steps of:

determining, based on the received ambient humidity level, a first voltage level setting for the secondary heater circuit, wherein the first voltage level setting is less than a full voltage level; and

wherein activating the secondary heater circuit comprises activating the secondary heater circuit at the first voltage level based on the determination that the ambient humidity level is greater than the preset humidity level.

8. The method of claim 7, wherein the full voltage level is selected from the group consisting of 120 volts, 230 volts, 240 volts, and 400 volts.

9. A method for controlling a heating system in a refrigerated display case comprising the steps of:

providing a refrigerated display case comprising: a primary heater circuit; a secondary heater circuit; and a sensor communicably coupled to the secondary heater circuit;

operating the primary heater circuit at a constant power level;

receiving an ambient temperature level from the sensor;

determining if the ambient temperature level is greater than a preset temperature level; and

activating the secondary heater circuit based on the determination that the ambient temperature level is greater than the preset temperature level.

10. The method of claim 9, wherein activating the secondary heater circuit comprises activating the secondary heater circuit for a predetermined amount of time, wherein the predetermined amount of time the secondary heater circuit is activated is based on the ambient temperature level.

11. The method of claim 10, wherein the predetermined amount of time the secondary heater circuit is activated increases as the ambient humidity level from the sensor increases.

12. The method of claim 9, further comprises the steps of:

determining, based on the received ambient temperature level, a first voltage level setting for the secondary heater circuit, wherein the first voltage level setting is less than a full voltage level; and

wherein activating the secondary heater circuit comprises activating the secondary heater circuit at the first voltage level based on the determination that the ambient temperature level is greater than the preset temperature level.

13. A method for controlling a heating system in a refrigerated display case comprising the steps of:

providing a refrigerated display case comprising: a primary heater circuit; a secondary heater circuit; and a dewpoint sensor communicably coupled to the secondary heater circuit and disposed outside of the display case;

operating the primary heater circuit at a constant power level;

receiving an ambient humidity level from the dewpoint sensor;

receiving an ambient temperature from the dewpoint sensor;

calculating a dewpoint temperature;

determining if the calculated dewpoint temperature is greater than a preset dewpoint temperature; and

activating the secondary heater circuit based on the determination that the calculated dewpoint temperature is greater than the preset dewpoint temperature.

14. The method of claim 13, wherein activating the secondary heater circuit comprises activating the secondary heater circuit for a predetermined amount of time, wherein the predetermined amount of time the secondary heater circuit is activated is based on the calculated dewpoint temperature.

15. The method of claim 14, wherein the predetermined amount of time the secondary heater circuit is activated increases as the calculated dewpoint temperature increases.

16. The method of claim 13, further comprises the steps of:

determining, based on the calculated dewpoint temperature, a first voltage level setting for the secondary heater circuit, wherein the first voltage level setting is less than a full voltage level; and

wherein activating the secondary heater circuit comprises activating the secondary heater circuit at the first voltage level based on the determination that the calculated dewpoint temperature is greater than the preset dewpoint temperature.

17. A method for controlling a heating system in a refrigerated display case comprising the steps of:

providing a refrigerated display case comprising: a display case comprising a plurality of walls defining at least one cavity; an aperture disposed though a first of the plurality of the walls to provide access to the cavity from an exterior of the display case; a door frame along the first wall and disposed about at least a portion of the aperture; at least one temperature sensor disposed along an outer exposed surface of the door frame; a heater circuit disposed within the door frame; and a dewpoint sensor communicably coupled to the heater circuit;

receiving at least one surface temperature reading from the at least one temperature sensor;

sensing an ambient temperature at the dewpoint sensor;

sensing an ambient relative humidity at the dewpoint sensor;

calculating a dewpoint temperature based on the sensed ambient temperature and sensed ambient relative humidity;

determining if the surface temperature reading is less than the calculated dewpoint temperature; and

activating the heater circuit based on the determination that the surface temperature reading is less than the calculated dewpoint temperature.

18. The method of claim 17, wherein the step of receiving at least one surface temperature reading comprises receiving a plurality of surface temperature readings from a plurality of temperature sensors disposed along the outer exposed surface of the door frame, the method further comprising:

determining a lowest surface temperature reading from the received plurality of surface temperature readings;

determining if the lowest surface temperature reading is less than the calculated dewpoint temperature; and

activating the heater circuit based on the determination that the lowest surface temperature reading is less than the calculated dewpoint temperature.

19. The method of claim 17, wherein the refrigerated display case further comprises a data storage device communicably coupled to a controller and the at least one temperature sensor, the data storage device configured to store control information for the heater circuit, the control information capable of being used to generate a chart of operational parameters for the heater circuit to educate the customer on the effect of humidity on energy consumption by the heater circuit.

20. The method of claim 17, wherein the refrigerated display unit further comprises an alarm communicably coupled to a controller controlling the heater circuit, wherein the controller evaluates the energy consumed by the heater circuit and initiates the alarm if the energy consumed by the heater circuit is greater than a predetermined level.

21. The method of claim 17, wherein the refrigerated display unit further comprises an alarm communicably coupled to a controller controlling the heater circuit, wherein the controller evaluates the received surface temperature reading to determine if the surface temperature remains below the calculated dewpoint temperature for a predetermined amount of time after activating the heater circuit and wherein the controller initiates the alarm based on a positive determination that the surface temperature remains below the calculated dewpoint temperature for a predetermined amount of time after activating the heater circuit.