BACKGROUND

Field of the Disclosure

[0001] The embodiments disclosed herein relate to systems and methods for controlling condensation, and more particularly, to electronic control systems for adjusting power to heaters to prevent condensation from forming, for example, on door windows and/or door frames of commercial refrigeration units.

Description of the Related Art

[0002] Glass doors are used in many commercial refrigerators, such as walk-in or reach-in refrigeration units commonly used in supermarkets. Electric heaters can be used to heat the glass doors to reduce or prevent the formation of condensation thereon. As a result, it can be easier for customers to see products inside commercial refrigerators with heated glass doors. Refrigeration units can use heaters to reduce or prevent the formation of condensation on various other surfaces or components (e.g., air vents and drain lines).

[0003] Some heating systems apply more heat to the glass doors than is needed to prevent condensation, which results in wasted energy. Also, because some of the heat applied to the glass doors can be transferred into the refrigerated space of the refrigeration units, applying more heat than necessary to the glass doors can also increase the amount of energy used by the cooling system of the refrigerator to maintain the cold temperature inside the refrigerator, which results in additional wasted energy.

[0004] Some existing controllers receive input from one or more sensors on the glass doors (e.g., at or near the surface a glass window on the door) and adjust the heater based on the input from the one or more sensors on the glass doors. The use of one or more sensors on the glass doors can result in an expensive and cumbersome system.

SUMMARY OF CERTAIN EMBODIMENTS

[0005] Various embodiments disclosed herein can relate to an anti-condensation control system that can include a first refrigeration unit having a first door window, a first heater thermally coupled to the first door window, a second refrigeration unit having a second door window, and a second heater thermally coupled to the second door window. The system can include an ambient temperature sensor configured to sense an ambient temperature outside the first and second refrigeration units, and an ambient humidity sensor configured to sense an ambient humidity outside the first and second refrigeration units. The system can include a controller in communication with the ambient temperature sensor, the ambient humidity sensor, the first heater, and the second heater. The controller can be configured to receive an ambient temperature input that is indicative of the ambient temperature, receive an ambient humidity input that is indicative of the ambient humidity, receive a target refrigeration temperature input indicative of a target internal temperature associated with the first refrigeration unit and the second refrigeration unit, receive a door window structure input indicative of a structural aspect of the first door window and the second door window, and receive a maximum heating power input indicative of a maximum heating power associated with the first heater and the second heater. The controller can be configured to adjust the first heater and the second heater based at least in part on the ambient temperature input, the ambient humidity input, the target refrigeration temperature input, the door window structure input, and the maximum heating power input.

[0006] The controller can be configured to adjust the first heater and the second heater based at least in part on the ambient temperature input that is indicative of the ambient temperature measured by a single ambient temperature sensor. The controller is configured to adjust the first heater and the second heater based at least in part on the ambient humidity input that is indicative of the ambient humidity measured by a single ambient humidity sensor.

[0007] The controller can be configured to receive a heating buffer input, and the controller can be configured to adjust the first heater and the second heater based at least in part on the heating buffer input. The controller can be configured to determine the heater control signal without any feedback information received from the first and second refrigeration units. The system can include one or more user input elements configured to receive input from a user, and the controller can be configured to receive the target refrigeration temperature input, the door window structure input, and the maximum heating power input via the one or more user input elements.

[0008] The system can include computer-readable memory in communication with the controller and configured to store the target refrigeration temperature input, the door window structure input, and the maximum heating power input. The controller can be configured to receive the target refrigeration temperature input, the door window structure input, and the maximum heating power input from the computer-readable memory.

[0009] Various embodiments disclosed herein can relate to an anti-condensation control system that can include an ambient temperature sensor configured to sense an ambient temperature outside one or more refrigeration units, an ambient humidity sensor configured to sense an ambient humidity outside the one or more refrigeration units, and a controller in communication with the ambient temperature sensor and the ambient humidity sensor. The controller can be configured to receive an ambient temperature input indicative of the ambient temperature, receive an ambient humidity input indicative of the ambient humidity, and receive a target refrigeration temperature input indicative of a target internal temperature associated with the one or more refrigeration units. The controller can be configured to determine a heater control signal for adjusting one or more heaters coupled to the one or more refrigeration units based at least in part on the ambient temperature input, the ambient humidity input, and the target refrigeration temperature input.

[0010] The controller can be configured to receive a door window structure input indicative of a structural aspect of one or more door windows on the one or more refrigeration units and to determine the heater control signal based at least on part on the door window structure input. The door window structure input can be indicative of whether the one or more door windows are double-paned or triple-paned.

[0011] The controller can be configured to receive a heater property input indicative of a property associated with the one or more heaters and to determine the heater control signal based at least in part on the heater property input. The heater property input is indicative of a maximum heating power associated with the one or more heaters. The controller can be configured to receive a heating buffer input and determine the heater control signal based at least in part on the heating buffer input.

[0012] The controller can be configured to output the heater control signal directly to the one or more heaters. The controller can be configured to output the heater control signal to a power distributor coupled to the one or more heaters. [0013] The ambient humidity sensor can be a relative humidity sensor and the ambient humidity input can be indicative of a relative ambient humidity outside the one or more refrigeration units. The ambient humidity sensor can be an absolute humidity sensor and the ambient humidity input can be indicative of an absolute ambient humidity outside the one or more refrigeration units.

[0014] The system can include one or more user input elements configured to receive input from a user, wherein the controller is configured to receive the target refrigeration temperature input via the one or more user input elements. The system can include computer-readable memory in communication with the controller and configured to store the target refrigeration temperature input. The controller can be configured to receive the target refrigeration temperature input from the computer-readable memory.

[0015] The controller can be configured to determine the heater control signal without any feedback information received from the one or more refrigeration units. The heater control signal can be configured to adjust a power level of the one or more heaters. The heater control signal can be configured to adjust a target temperature of the one or more heaters. The heater control signal can be configured to adjust a duty cycle associated with the one or more heaters. The heater control signal can be associated with a pulse-width modulation of power delivered to the one or more heaters.

[0016] The controller can be configured to identify a value in a look-up table based at least in part on the ambient temperature input, the ambient humidity input, and the target refrigeration temperature input, and the heater control signal can be based at least in part on the identified value.

[0017] The controller can be configured to determine an estimated dew point, and the heater control signal can be based at least in part on the estimated dew point. The controller can be configured to determine an estimated surface temperature of one or more controlled surfaces on the one or more refrigeration units, and the heater control signal can be based at least in part on the estimated dew point and the estimated surface temperature. The one or more controlled surfaces can include one or more door windows on the one or more refrigeration units. The controller can be configured to determine a heater control signal by utilizing a single formula or look-up table. The system can further include the one or more refrigeration units.

[0018] Various embodiments disclosed herein can relate to a method of reducing or preventing the formation of condensation on one or more controlled surfaces in one or more refrigeration units. The method can include receiving, by a controller comprising hardware that includes one or more computing devices, an ambient temperature input indicative of an ambient temperature outside the one or more refrigeration units, receiving, by the controller, an ambient humidity input indicative of an ambient humidity outside the one or more refrigeration units, and receiving, by the controller, a target refrigeration temperature input indicative of a target internal temperature associated with the one or more refrigeration units. The controller can be configured to determining, by the controller, a heater control signal configured to adjust one or more heaters coupled to the one or more controlled surfaces in the one or more refrigeration units based at least in part on the ambient temperature input, the ambient humidity input, and the target refrigeration temperature input.

[0019] The method can include receiving a controlled surface structure input indicative of a structural aspect of the one or more controlled surfaces, and the heater control signal can be based at least on part on the controlled surface structure input. The method can include a maximum heating power input indicative of a maximum heating power of the one or more heaters, and the heater control signal can be based at least in part in part on the maximum heating power input. The method can include receiving a heating buffer input signal, and the heater control signal can be based at least in part in part on the heating buffer input signal.

[0020] The method can include outputting the heater control signal to the one or more heaters coupled to the one or more refrigeration units. The heater control signal can be configured to adjust a power level of the one or more heaters. The heater control signal can be configured to adjust a duty cycle associated with the one or more heaters.

[0021] Determining a heater control signal can include identifying a value in a look-up table based at least in part on the ambient temperature input, the ambient humidity input, and the target refrigeration temperature input. [0022] Various embodiments disclosed herein can relate to a non-transitory computer-readable medium storing instructions that when executed by computing hardware, cause the computing hardware to perform operations that include receiving an ambient temperature input, receiving an ambient humidity input, receiving a target refrigeration temperature input indicative of a target internal temperature associated with one or more refrigeration units, and determining a heater control signal for adjusting one or more heaters coupled to the one or more refrigeration units based at least in part on the ambient temperature input, the ambient humidity input, and the target refrigeration temperature input.

[0023] The operations can also include outputting the heater control signal to the one or more heaters coupled to the one or more refrigeration units.

[0024] The non-transitory computer-readable medium can store instructions that cause computing hardware to perform various other operations discussed herein (e.g., discussed in connection with the methods mentioned above, or mentioned elsewhere in this application.

[0025] Various embodiments disclosed herein can relate to a heater control system that can include an ambient humidity receiver configured to receive an ambient humidity signal indicative of an ambient humidity, an ambient temperature receiver configured to receive an ambient temperature signal indicative of an ambient temperature, and one or more user input elements configured to receive a target surface temperature input that is indicative of a target temperature associated with a controlled surface. The system can include a controller configured to determine a heater control signal for adjusting a heater coupled to the controlled surface based at least in part on the ambient humidity, the ambient temperature, and the target surface temperature input.

[0026] The humidity receiver can be configured to receive an ambient relative humidity signal indicative of a relative ambient humidity. The humidity receiver can be configured to receive an ambient absolute humidity signal indicative of a relative absolute humidity.

[0027] The system can further include a refrigeration unit that includes the controlled surface. The controlled surface can include a transparent window. [0028] The system can further include an ambient humidity sensor configured to send the ambient humidity signal to the ambient humidity receiver. The system can further include an ambient temperature sensor configured to send the ambient temperature signal to the ambient temperature receiver.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Fig. 1 illustrates an example embodiment of an anti-condensation system.

[0030] Fig. 2 illustrates another example embodiment of an anti-condensation system.

[0031] Fig. 3 illustrates an example embodiment of a heater control system and ambient sensors.

[0032] Fig. 4 illustrates an example embodiment of a heater control system that includes one or more user input elements and one or more information output elements.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

[0033] Some embodiments disclosed herein provide anti-condensation systems that can prevent or reduce the formation of condensation on a controlled surface, such as a door window or door frame on a commercial refrigeration unit. Some embodiments do not include sensors for directly measuring the temperature of the door window or other controlled surface. Some embodiments include sensors for sensing the ambient surroundings outside the refrigerator, and can use those ambient readings to control a heater associated with the door window or other controlled surface. In some embodiments, the readings of the ambient surroundings outside the refrigerator can be used to determine the amount of heat that should be applied to the door window or other controlled surface in order to prevent condensation from forming on the door window or other controlled surface. The system can control the heater based on a measured ambient temperature, a measured ambient humidity, a target temperature that a refrigeration unit is set to, information about the structure of the door window (e.g., double-paned or triple-paned), and the maximum heating power associated with the heater, or various combinations of these inputs. Some of these inputs can be specified by a user, e.g., through a user interface on the system. As the ambient temperature and ambient humidity change over time, the system can automatically adjust the heater accordingly, to prevent or reduce the formation of condensation (e.g., on a door window on a refrigeration unit).

[0034] Although various examples are provided with reference to a "refrigeration unit" or "refrigerator," it will be appreciated that the embodiments disclosed herein may be used to control condensation on various other types of units, such as commercial showcases and display cases. As used herein, "refrigeration unit" and "refrigerator" shall refer to various types of display cases and enclosures configured to cool an interior chamber, including, for example, commercial refrigerators and commercial freezers.

[0035] While various examples and descriptions are provided with reference to transparent windows (e.g., made of glass), which can be located on refrigerator doors, it will be appreciated that the embodiments disclosed herein may be used to control condensation on various other surfaces, such as on door frames, air vents, drain lines, or control components of a refrigeration unit, etc. Furthermore, various embodiments and features can be used to reduce or prevent condensation from forming on a variety of different objects, such as car windows, glass tables, displays at a supermarket, etc.

[0036] Furthermore, the terms "control," "prevent," "reduce," and "remove" condensation may sometimes be used interchangeably. Any one of those terms may refer to any combination thereof. Thus, "preventing condensation" may also refer to "removing condensation" or "reducing condensation." In some cases, these terms can be used to refer to suppression of condensation even if condensation is not always completely absent.

[0037] Fig. 1 illustrates an anti-condensation system 100 for controlling condensation on one or more refrigeration units 132a-c. Referring to Fig. 1, an anti- condensation system 100 can include heaters 136a-c coupled to controlled surface 134a-c (e.g., windows on refrigerator doors). The anti-condensation system 100 can also include a heater control system 102, which can receive a variety of inputs 110, 114, 120, 126, 122, 124 and can output a signal to the heaters 136a-c in order to control the heaters 136a-c and the temperature on the door windows 134a-c. Although examples are provided with reference to glass door windows, it will be appreciated that the anti-condensation system 100 can work with various other surfaces on which it is desirable to reduce condensation. The door windows 134a-c can include a glass material or other transparent material. In addition, although Fig. 1 illustrates three refrigeration units 132a-c, it will be appreciated that the embodiments disclosed herein can be used with a single refrigeration unit 132a, or with various other numbers of refrigeration units (e.g., 2, 4, 5, 8, 12, 20, or more refrigeration units).

[0038] In some embodiments, the door windows 134a-c can be coated with a thin transparent electrically conductive layer for heating the door windows 134a-c. The heaters 136a-c may also be coupled to the door windows 134a-c in any number of ways that are configured to heat the door windows 134a-c. In some embodiments, the heaters 136a-c can reduce or eliminate the condensation (e.g., by causing the condensation to vaporize). Also, the heaters 136a-c can raise the temperature of the door windows 134a-c (e.g., and the area immediately surrounding the door windows 134a-c) such that condensation does not form on the door windows 134a-c, or so that less condensation forms on the door windows 134a-c than would form without the heaters 136a-c.

[0039] A heater control system 102 can be in communication with the heaters 136a-c that are coupled to the door windows 134a-c (or other controlled surfaces). The heater control system 102 may output a signal that can be used to control the heaters 136a-c (e.g., to control the amount of heat generated by the heaters 136a-c). In some embodiments, the heater control system 102 does not receive any signals from the refrigeration units 132a-c. The heater control system 102 can be configured to determine a heater control output signal that does not depend on any input fed back to the heater control system 102 (e.g., from the heaters 136a-c or from any other sensor or component on the refrigeration units 132a-c). Accordingly, in some embodiments, the anti-condensation system 100 is not a feedback system.

[0040] Referring to Fig. 2, in some embodiments, heater control system 102 can provide a heater control signal to a power distributor 138 (e.g., a variable transformer), which can be configured to adjust the power delivered to the one or more heaters 136a-c based at least in part on the heater control signal output by the heater control system 102. For example, the power distributor 138 can be a variable transformer that is configured to change the voltage that is delivered to the heaters 136a-c based at least in part on the heater control signal received from the heater control system 102. The power distributor 138 can be coupled to the power grid, and can be configured to send power from the power grid to the heaters 136a-c. One power distributor 138 can be configured to distribute power to multiple heaters 136a-c based on the heater control signal. In some embodiments, multiple power distributors 138 (e.g., variable transformers) can be used (e.g., depending on the number heaters 136a-c). For example, the heater control system 102 can send heater control signals to multiple power distributors 138 (e.g., variable transformers), which can each distribute power to one or more heaters 136a-c. Accordingly, one heater control system 102 can be used to control the heaters 136a-c on a large number of refrigeration units 132a-c, in some embodiments.

[0041] With reference again to Figure 1, in some embodiments, the heater control system 102 can be configured to send heater control signals directly to the heaters 136a-c. In some embodiments, the heater control system 102 can deliver power to the heaters 136a-c. Thus, the heater control signal can be an adjust amount of electrical power that is used to drive a heater 136a-c. In some embodiments, the heater control system 102 can be configured to receive power from the power grid and output an adjusted level of power to the one or more heaters 136a-c. For example, the heater control system 102 can include a variable transformer (not shown in Figure 1) or other power distributor. In some embodiments, the heaters 136a-c can be configured to adjust their power levels based on the heater control signal output by the heater control system 102. For example, one or more of the heaters 136a-c can be coupled to the power grid and can include a variable transformer or other power distributor configured to adjust the power that the heater 136a-c uses based at least in part on the heater control signal from the heater control system 102.

[0042] The heater control system 102 can receive a variety of inputs, which can be used by the heater control system 102 to determine the heater control signal (e.g., which can indicate the amount of heat that should be applied by the heaters 136a-c to prevent condensation). As shown, for example, in Fig. 1, the anti-condensation system 100 can include a temperature sensor 110 and a humidity sensor 114 to sense the ambient settings (e.g., ambient temperature and ambient humidity) outside the refrigerators 134a-c. The heater control system 102 can receive the ambient temperature reading and the ambient humidity reading sensed by the temperature sensor 1 10 and humidity sensor 114, respectively. In some embodiments, the heater control system 102 can use the readings of the ambient temperature and the ambient humidity to control the heaters 136a-c (e.g., to determine a heater control signal). In some embodiments, heater control system 102 can determinate the amount of heat that should be applied to the door windows 134a-c in order to prevent condensation. In some embodiments, the anti-condensation system 100 does not include temperature sensors or humidity sensors at or near the door windows 134a-c. In some embodiments, the anti-condensation control system 100 is not a feedback system.

[0043] The heater control system 102 can determine the heater control signal based at least in part on a target internal temperature 120 that is set for the inside of the one or more refrigeration units 132a-c. For example, a target internal temperature 120 for a refrigeration unit 132a-c (e.g., a freezer) that is designed to freeze food items may be about 0°F. As another example, a set temperature for a refrigeration unit 132a-c that is designed to keep food items cold without freezing the food items may be about 35°F. In some embodiments, the heater control system 102 can assume that the temperature inside the refrigeration unit 132a-c is a constant value held at the target internal temperature 120. Thus, although the actual internal temperature may vary from the target temperature 120 for short periods of time (e.g., after a user opens the door to the refrigeration unit 132a-c), the heater control system 102 can assume that the target internal temperature 120 is constant. The target internal refrigerator temperature 120 may be entered by a user. Thereby, the heater control system 102 may be configured to receive the target internal refrigerator temperature 120 via one or more user input elements.

[0044] The heater control system 102 can be configured to determine the heater control signal based at least in part on the window structure 122 of one or more door windows 134a-c on the one or more refrigeration units 132a-c, such as whether the one or more door windows 134a-c are double-paned or triple-paned. For example, in some embodiments, a user may enter an input indicating whether the door windows 134a-c are double-paned or triple-paned. The control system 102 can be configured to receive user input regarding the window structure 122 of the door windows 134a-c (e.g., via one or more user input elements). [0045] The heater control system 102 can be configured to determine the heater control signal based at least in part on a heater property 124 of the one or more heaters 136a-c, such as a maximum heating capability of the one or more heaters 136a-c. The heater property 124 can include an indication of a heater type, heater name, heater make, heater model, heater efficiency, etc. For example, if the heater control signal is configured to indicate a percentage of the maximum heater power for operating the one or more heaters 136a-c and if the one or more heaters 136a-c have a relatively high maximum heating capability, the heater control system 102 can be configured to output a heater control signal that corresponds to a relatively low percentage power for operating the one or more heaters 136a-c. The control system 102 can be configured to receive user input regarding the heater property 124 (e.g., via one or more user input elements).

[0046] In some embodiments, the heater control system 102 can determine the heater control signal based at least in part on a heating buffer 126, which can represents a deviation from an estimated minimum amount of heating necessary to prevent condensation. Thus, for example, if the heater control system 102 determines that a heater power level of 50% is the minimum power level sufficient to prevent condensation, the heating buffer 126 can cause the heater output signal to indicate a heater power level of over 50% by some amount that is based at least in part on the heating buffer 126. For example, a relatively high heating buffer 126 can cause the heater output signal to indicate a power level of 60%, and a relatively low heating buffer 126 can cause the heater control signal to indicate a power level of 51 %, and a heating buffer of 0 can cause the heater control signal to indicate a power level of 50%. Thus, a high heating buffer 126 setting can be used to more reliably reduce or eliminate condensation while sacrificing some energy efficiency. In some embodiments, the heating buffer 126 can be used to generate a heater control signal that corresponds to a heater power level that is below the estimated minimum heater power level that is sufficient to prevent condensation. Continuing the example discussed above, a negative heating buffer 126 can cause the heater power level to decrease to 45%. Thus, low or negative heating buffer 126 settings can be used to increase energy efficiency, while increasing the risk of allowing some condensation. The control system 102 can be configured to receive user input regarding the heating buffer 126 (e.g., via one or more user input elements). Accordingly, the heating buffer 126 setting can allow a user to adjust the heating control system 102 depending, for example, on the user's preferences regarding energy efficiency vs. reliability of condensation prevention. Also, if a user notices that current heating buffer setting 126 is not providing satisfactory condensation prevention (e.g., possibly due to variations between the actual humidity at the door windows 134a-c and the measured ambient humidity from the ambient humidity sensor 114), the user can change the heating buffer 126 to achieve the desired condensation prevention.

[0047] In some embodiments, some or all of the input values (e.g., any combination of the ambient temperature, the ambient humidity, the target refrigeration temperature 120, the door window structure 122, the heater property 124, and the heating buffer 126) can be used to control the heaters 136a-c on two or more of the refrigeration units 132a-c, or on all the refrigeration units 132a-c in the anti-condensation control system 100. For example, a user may input a single value for one of the inputs (e.g., target refrigeration temperature 120), and the heater control system 102 can use the single value for controlling the heaters 136a-c on some or all of the refrigeration units 132a-c. In some embodiments, the heater control system 102 can determine a heater control signal that is used to control the heaters 136a-c on multiple refrigeration units 132a-c or on all the refrigeration units 132a-c in the system 100.

[0048] In some embodiments, the heater control system 102 can determine different heater control signals for different refrigeration units 132a-c (either individually or in zones or groups). The heater control system 102 can be configured to enable the user to enter different values for different refrigeration units 132a-c, for one, or some, or all of the inputs (e.g., any combination of the ambient temperature, the ambient humidity, the target refrigeration temperature 120, the door window structure 122, the heater property 124, and the heating buffer 126). For example, a user can enter different target refrigeration temperatures 120 for different refrigeration units 132a-c (either individually or in zones or groups). In some embodiments, a user can enter a different heating buffer 126 value for different refrigeration units 132a-c (either individually or in zones or groups). For example, if a user notices that a particular refrigeration unit 132a-c in the system 100 does not experience satisfactory condensation prevention, the user can increase the heating buffer 126 for that refrigeration unit 132a-c individually. In some embodiments, a user can enter the same value for some refrigeration units 132a-c and different values for other refrigeration units 132a-c. Thus, the control system 102 can be configured to allow a user to enter a variety of inputs in a variety of ways such that the heaters 136a-c apply a desired amount of heat to the windows 134a-c to prevent or reduce condensation. Thus, one heater control system 102 can be used to control heaters 136a-c on different refrigeration units 132a-c having different settings (e.g., different target refrigeration temperatures 120), different properties (e.g., different heater types), different surrounding environments (e.g., different ambient temperatures or different ambient humidities), etc. In some embodiments, the heater control system 102 can be configured to receive and/or use different inputs for different zones or groups, and each zone or group can include one or more refrigeration units 132a-c that are controlled using the same inputs.

[0049] Multiple ambient temperatures sensors 110 can be included, and their respective readings can be combined (e.g., averaged) into a single value for use in determining a heater control signal. The multiple ambient temperature sensors 110 can be arranged into different zones or groups such that the different zones or groups have different ambient temperature values from the different sensors 110. In some embodiments, different refrigeration units 132a-c can have a different temperature values applied to them depending on the distance from the different refrigeration units 132a-c to the different ambient temperature sensors 110. Similarly, multiple ambient humidity sensors 1 14 can be included, and their respective readings can be combined (e.g., averaged) into a single value for use in determining a heater control signal. The multiple ambient humidity sensors 114 can be arranged into different zones or groups such that the different zones or groups have different ambient humidity values from the different sensors 114. In some embodiments, different refrigeration units 132a-c can have a different ambient humidity values applied to them depending on the distance from the different refrigeration units 132a-c to the different ambient humidity sensors 114.

[0050] Using a variety of combinations of the inputs, the heater control signal 102 can determine the heater control signal, which can correspond to an amount of heat to apply to the heaters 136a-c in order to prevent condensation. In some embodiments, the heater control system 102 can utilizes a formula or a look-up table to determine the heater control signal. In some embodiments, the heater control signal can be a power signal configured to be delivered directly to the heaters 136a-c. In some embodiments, the heater control signal can be instructions that can be configured to be delivered to a different component (e.g., a variable transformer 138) for applying the appropriate power to the heaters 136a-c.

[0051] Fig. 3 illustrates an example embodiment of a heater control system 102 and an ambient temperature sensor 110 and an ambient humidity sensor 114. Referring to Fig. 3, the ambient temperature sensor 110 can connect to the heater control system 102 via the ambient temperature signal receiver 108. The ambient temperature signal receiver 108 can include a port, plug, slot, wire, cable, or any other mechanism for allowing a connection between the temperature sensor 100 and the heater control system 102. In some embodiments, the ambient temperature signal receiver 108 can be a wireless communication system that is configured to receive information from the ambient temperature sensor wirelessly. In some embodiments, the ambient temperature sensor 110 is connected to the heater control system 102 by a wire that plugs in to the ambient temperature signal receiver 108. Similarly, the heater control system can include an ambient humidity signal receiver 112 configured to receive a signal from the ambient humidity sensor 112. The ambient humidity signal receiver 112 can include a port, plug, slot, wire, cable, wireless communication system, or any other mechanism for allowing transfer of information between the humidity sensor 114 and the heater control system 102. In some embodiments, the ambient temperature signal receiver 108 and the ambient humidity signal receiver 112 can be incorporated into one receiver that is provided for both the temperature sensor 110 and the humidity sensor 114. For example, one cable can transmit data from both the ambient temperature sensor 110 and the ambient humidity sensor 114, or a single wireless communication system can receive information from both the ambient temperature sensor 110 and the ambient humidity sensor 114.

[0052] The ambient temperature sensor 110 and the ambient humidity sensor 114 may be placed at any location outside the refrigeration units 132a-c that is suitable for sensing the ambient temperature and humidity. For example, the ambient sensors 110, 114 may be placed in the same room with the one or more refrigeration units 132a-c, on a ceiling, in a hallway just outside the room the refrigeration units 132a-c are in, in the middle of the room with the refrigeration units 132a-c, adjacent or near the refrigeration units 132a-c, adjacent or near heater control system 102, and so forth. In some embodiments, the ambient temperature sensor 110 and/or the ambient humidity sensor 114 can be incorporated into the heater control system 102, such as within or on the same panel or housing the supports one or more of the other components of the heater control system 102. Further, the ambient sensors 110, 114 may comprise sensors that are already installed in a room or a building. Thus, the anti- condensation system 100 according to some embodiments need not provide additional sensors, but may use sensors already installed in a building. In some embodiments, the temperature sensor 110 and/or the humidity sensor 114 can be mounted onto a housing containing the heater-control system 102, or can be incorporated into the heater-control system (e.g., disposed inside or on a housing of the heater-control system).

[0053] As shown in Fig. 3, in some embodiments, a single ambient temperature sensor 110 and/or a single ambient humidity sensor 114 can be used by the anti-condensation system 100. However, it will be appreciated that any suitable number and combination of ambient sensors 110, 114 can be used.

[0054] The humidity sensor 114 may be a relative humidity sensor configured to measure the relative humidity of the ambient area outside the refrigeration units 132a-c, or an absolute humidity sensor configured to measure the absolute humidity (e.g., amount of water vapor per volume) of the ambient area outside the refrigeration units 132a-c. As used herein, "ambient sensors" can refer to any combination of suitable sensor types that are capable of measuring values relating to ambient temperature and/or ambient humidity. Further, any combination of these ambient sensors 110, 114 may be used with the anti-condensation system 100.

[0055] In some embodiments, the anti-condensation system 100 utilizes only one ambient temperature sensor 110 and only one ambient humidity sensor 114, and in some cases the heater control system 102 can be used to control heaters 136a-c on multiple refrigeration units 132a-c (e.g., 2, 4, 8, 12, 20, or more refrigeration units). The readings obtained from the ambient sensor(s) 110, 114 may be applied to one refrigeration unit, two refrigeration units, or a plurality of refrigeration units 132a-c. In some embodiments, the ambient sensor readings are applied to a plurality of refrigeration units 132a-c in the same room. In some embodiments, the ambient sensor readings are applied to a plurality of refrigeration units 132a-c in the same building.

[0056] In some embodiments, a plurality of ambient sensors 110, 114 may be used, as discussed herein. For example, an anti-condensation 100 system may include two ambient temperature sensors 110, two ambient humidity sensors 114, or more ambient sensors 110, 114.

[0057] Referring to Fig. 3, in use, the ambient temperature sensor 110 and the ambient humidity sensor 114 can generate respective signals indicative of ambient temperature and humidity outside a refrigeration unit 132a-c. The signals can be received by the ambient temperature sensor receiver 108 and the ambient humidity sensor receiver 112 on the heater control system 102. In some embodiments, the signal(s) from the ambient temperature sensor 110 and/or the ambient humidity sensor 114 can be sent to a controller 116 or to a computer-readable memory 118 (e.g., via the ambient temperature sensor receiver 108 and/or the ambient humidity sensor receiver 112). In some embodiments, data relating to ambient temperature and/or the ambient humidity can be stored in the computer-readable memory 118. The ambient temperature signal and/or the ambient humidity signal can be sent from the computer-readable memory 118 to the controller 116. The signals relating to ambient temperature and/or humidity may travel any path according to the electronic circuitry in the heater controller system 102 to the controller 116. Thus, the controller 116 can be configured to receive signals indicative of the ambient temperature and ambient humidity outside a refrigerator 132a-c according to some embodiments. In some embodiments, the controller 116 includes computing hardware components, such as one or more processors, one or more integrated circuits, etc., as discussed herein.

[0058] Referring to Fig. 3, the heater controller system 102 can also include one or more user input elements 128 configure to enable a user to enter a variety of information associated with the anti-condensation system 100 (e.g. internal target temperature 120, heater buffer value 126, structural aspect of a window 122, and/or a property of a heater 124). The one or more user input elements 128 can include one or more buttons, knobs, switches, dials, touchscreens, and the like, or any suitable combination thereof, by which the user can enter information. In some embodiments, the inputs can be entered via a wireless receiver, e.g., via WiFi, Bluetooth, radio frequency (rF), and other wireless technologies. Accordingly, some or all of the one or more user input elements can be located remotely from the controller or from other component of the heater control system 102. In some embodiments, the system can be configured to enable a user to input information using a remote control device. In some embodiments, the system can be configured to allow a user to input information via a mobile device (e.g., utilizing a smart phone or tablet application) or a remote computer system.

[0059] Referring to Fig. 3, one or more information output elements 130 can be included to output information, and can be configured to provide the information to a user. In some embodiments, the one or more information output elements 130 can display current settings and/or information input by a user, e.g., thereby enabling a user to see the information as it is entered. The one or more information output elements 130 can include one or more displays, indicator lights, audio output devices, wireless transmitters, touchscreens, or any other mechanism for outputting information (e.g., to the user or to a database or archive). In some embodiments, the one or more information output elements 130 can output (e.g., display) information about the anti-condensation system 100, such as the percentage or amount of power being used to drive the heaters 136a-c, the amount of estimated energy savings, etc. In some embodiments, the user input elements 128 and the information output elements 130 can be integrated together, e.g., such as a touch screen. In some embodiments, the one or more output elements 130 can be configured to output information (e.g., the current settings, the heater control signals, a percentage or amount of power used by the heaters, estimated energy savings, a percentage of output power vs. full output power, or an average percentage of output power vs. full output power during a certain period, etc.) to a database or archive, which can be stored in a computer-readable memory device.

[0060] Fig. 4 illustrates one embodiment of a heater control system 102 that includes user input elements 128 and information output elements 130. Referring to Fig. 4, the heater control system 102 can include a housing 150, which can enclosure or support various components of the heater control system 102. Some features of the heater control system 102 are hidden from view in Figure 4 (e.g., disposed inside the housing 102). The housing 102 can be configured to be mounted on a wall. The information output elements 130 shown in Fig. 4 can include indicator lights and displays, although many variations are possible. The displays can be alpha-numeric displays, which can be configured to display numbers associated with information input by a user, stored values associated with inputs that affect the determination of the heater control signal, reporting information regarding the heater control signal or energy savings, or any other values discussed herein. The user input elements 128 show in Fig. 4 can include a plurality of push buttons, although many variations are possible.

[0061] A display 152 can be configured to display the percentage of the current power level to the maximum power level. In the configuration shown, the heater control system 102 is driving one or more heaters at a power level that is 35.9% of the full power level. The display 152 can also be configured to show the average percentage of the current power level to the maximum power level over a period of time. A button 154 can enable a user to switch the display 152 between the percentage power and the average percentage power over the time period, and indicator lights 156 and 158 can provide an indication of whether the display 152 is showing the percentage power or the average percentage power over the time period. A reset button 160 can enable the user to reset the average percentage power (e.g., by restarting the time period used for the average).

[0062] A display 162 can be configured to display values input by the user or values stored in the heater control system 102. For example, in Figure 4, the display 162 shows a heating buffer value of 1.0. Buttons 164 and 166 can enable a user to modify the increase or decrease the value of the input displayed on the display 162. Button 168 can enable a user to change which input that is displayed on the display 162, and indicator lights 170, 172, and 174 can provide an indication of which input is being displayed on the display 162. For example, in some cases the button 168 can enable the user to switch between the heating buffer values 126 of three different refrigeration units 132a-c or three different zones or groups of refrigeration units 132a-c. In some embodiments, similar features can be used to enable a user to modify other input values discussed herein, such as the target refrigeration temperature 120, the door window structure information 122, the heater property 124, etc. [0063] The heater control system 102 can include a power indicator light 176 configured to indicate whether the heater control system 102 has power or is turned on, etc. A run indicator light 178 can indicate whether the system 102 is running. Indicator lights 180, 182, 184, and 186 can indicate whether information is being transferred (Tx) or received (Rx) between the heater control system 102 and, for example, the ambient temperature sensor 110, the ambient humidity sensor 114, the heaters 136a-c, an external input or output device, etc.

[0064] With reference again to Fig. 3, in some embodiments, information used to determine the heater output signal can be stored in computer-readable memory 118 in the heater control system 102. For example, a target internal refrigeration temperature 120 can be stored in a computer-readable memory 118. One or more, or all, of window structure information 122, heater property information 124, and heating buffer information 126 can also be stored in the computer readable-memory 118, according to some embodiments. In some embodiments, computer-readable memory 118 can be in electronic communication with the at least one user input elements 128 and/or the one or more information output elements 130, and the system 102 can be configured to allow a user to input and/or modify the information that is stored in the computer-readable memory 118. Further, the computer- readable memory 118 can have instructions that can be executed by the controller 116 to implement the various operations and features described herein.

[0065] Information input by the user can be transferred from the user input elements 128 to the computer-readable memory. In some embodiments, the controller 116 can receive information from the one or more user input elements 128, and the controller 116 can cause the information to be stored in the computer-readable memory, or the controller 116 can use the information to determine the heater control signal without first storing. In some embodiments, data stored in the computer readable memory 118 can sent to the controller 116. In some embodiments, the controller 116 can use user input data and/or information stored in the computer-readable memory and/or ambient temperature and ambient humidity readings to determine a heater control signal 106. A heater control output 104 can be included in a heater control system 102 to output the heater control signal 106 (e.g., to the heaters 136a-c or to an intermediate device such as a variable transformer 138 or other power distributor). The heater control output 104 can transfer information, for example, by wire, by cable, by optical signals, by wireless signals. Accordingly, the heater control output 104 can include a port, plug, slot, wire, cable, wireless communication system, or any other mechanism for allowing transfer of information between the heater control system 102 and the heaters 136a-c, the variable transformer 138, etc.

[0066] In some embodiments, the heater control system 102 sends a heater control signal 106 to adjust the heaters 134a-c coupled to refrigeration units 132a-c, thereby preventing or reducing condensation. The heater control signal may adjust the heater 114 in any number of ways.

[0067] In some embodiments, the heater control system 102 causes the power level of the heater 134a-c to be adjusted. For example, the heater control system 102 may output a heater control signal that causes the power level to be a percentage of the maximum power of the heater. In some embodiments, the heater can remain on for extended periods of time, and the amount of heat generated by the heater can be adjusted by changing the amount (e.g., percentage) of power applied while the heater remains on.

[0068] In some embodiments, the heater control system 102 can output a heater controller signal that is configured to adjust a duty cycle of the one or more heaters 134a-c. For example, power to the one or more heaters 134a-c may turn on and off (e.g., in periodic cycles), with the duty cycle defining the amount of time (e.g., as a percentage or ratio) that the heater 134a-c spends in an "on" state as opposed to an "off state. A higher duty cycle can therefore correlate to more heat being applied to the glass windows 134a-c, whereas a lower duty cycle can correlate to less heat being applied to the glass windows 134a-c. For example, a duty cycle of 70% can indicate that the heater 134a-c is in an on state (or high power state) for 70% of a period of time, and that the heater is in an off state (or a low power state) for 30% of the period of time. In some embodiments, the heater control system 102 can be configured to apply a pulse-width modulation to the duty cycle.

[0069] In some embodiments, the heater control system 102 can output a heater control signal that relays a desired temperature to the one or more heaters 134a-c. Thus, for example, if the heater control system 102 determines that the temperature on the door windows 134a-c should be 40°F, an output signal indicating "40°F" may be sent to the one or more heaters 134a-c, and the one or more heaters 134a-c can be configured to adjust its heat output to try to bring the window to a temperature of 40°F.

[0070] To determine a heater control signal 106, the controller 116 can take into account a variety of combinations of the inputs.

[0071] In some embodiments, the controller 116 determines a heater control signal 106 based at least in part on the ambient humidity (e.g., measured by the ambient humid sensor 114), the ambient temperature (e.g., measured by the ambient temperature sensor 110), the target internal refrigeration temperature 120 of the one or more refrigeration units 134a-c (e.g., as inputted by a user), window structure information 122 (e.g., inputted by a user), and information regarding a heater property 124 such as a maximum heating capability (e.g., inputted by a user). In some embodiments, additional inputs (e.g., a heater buffer value 126, which can be inputted by a user) can be used to determine the heater control signal 106. In various embodiments disclosed herein, the heater control system 102 can be configured to allow a user to specify (e.g., via the one or more user input elements 128) a minimum heating value and/or a maximum heating value. The minimum heating value and/or maximum heating value can be stored in the computer-readable memory 118 (although not shown in Figure 1), and the controller 116 can determine the heater control signal 106 based at least in part on the minimum heating value and/or the maximum heating value. For example, the minimum heating value can set a floor, such that the heater control system 102 will not output a heater control signal that is associated with a heating value below the minimum heating value. Similarly, the maximum heating value can set a ceiling, such that the heater control system 102 will not output a heater control signal that is associated with a heating value that is above the maximum heating value.

[0072] In some embodiments, the current heater control signal 106 that is being output by the system 102, and/or some number of prior heater control signals 106 can be used to determine the heater control signal 106, although in some embodiments, no current or past heater control signals 106 are considered by the controller 116 in making the determination of the new heater control signal 106. In some embodiments, some of the inputs listed above can be omitted from the determination of the heater control signal 106. For example, if a heater control system 102 is configured to be used with only one type of heater, or if the heater output signal 106 is configured to specify a target heater power, or a target heated temperature, instead of a percentage of the maximum heater power, the information regarding a heater property 124 can be omitted from the determination. If a heater control system 102 is configured to be used with only refrigeration units 132a-c that are set to a particular refrigeration temperature or that have a particular door window structure (e.g., double-paned or triple-paned), the inputs of the target refrigeration temperature 120 and or the window structure information 122 can be omitted from the determination of the heater control signal 106. In some embodiments, an inputs can be consider by the controller 116 in determining the heater control signal 106 even if the input is set (e.g., not adjustable by a user or by a sensor). For example, if a heater control system 102 is configured to be used with only a particular type of heater, the heater property information 124 can be stored in a computer memory or can be incorporated directly into a formula or directly into values in a look-up table such that the heater property information is still influences the determination of the heater control signal 106.

[0073] In some embodiments, the ambient humidity (measured by humidity sensor 114) (e.g., relative humidity and/or absolute humidity) and target internal refrigeration temperature 120 can be used to determine the heater control signal 106, without using the other inputs discussed above. In some embodiments, the controller 116 may utilize the ambient humidity (e.g., absolute humidity and/or relative humidity), ambient temperature, and target internal refrigeration temperature 120 to determine the heater control signal 106. In some embodiments, additional user inputs, such as a heater buffer value 126, window structure aspect 122, and property of a heater 124 may also be taken into account by the controller 116 when determining the heater control signal 106. Some embodiments do not utilize any temperature sensors to directly measure the temperature of a window 134a-c on a refrigerator 132a-c, or any humidity sensors 114 to directly measure the humidity at or near a window 134a-c on a refrigerator 132a-c, to determine a heater control signal 106. Accordingly, in some embodiments, the heater control system is not a feedback system.

[0074] The controller 116 may determine the heater control signal 116 by utilizing one or more look-up tables, according to some embodiments. The one or more look-up tables may comprise an array of values associated with various combinations of inputs (e.g. ambient temperature, ambient humidity, target internal temperature 120, window structure aspect 122, property of a heater 124 (e.g., maximum heating power of the glass door), and/or heater buffer 126) with an output (e.g. heater control signal 106, such as heater power level). For example, the look-up table(s) may indicate that for ambient temperature of 35°C, ambient relative humidity of 75%, a target internal refrigeration temperature 120 of - 24°C, and a window structure of triple-paned glass, max heating power 124 on the window of 120 watts per square meter, and a heating buffer of +1°C, the power level for a heater (with buffering) should be 74% (e.g., 74% of the total max power of 120Watt per square meter), the duty cycle of the heater should be 74%, or that the temperature should be at least 30.8°C. Various other inputs (e.g., the maximum heating capability of the heater and/or a heating buffer value 126) can also be considered by the look-up table(s) in determining the heater output signal 106. In some embodiments, a single look-up table can be used to directly determine the heater control signal 106 based on the various inputs, or multiple look-up tables can be used to make intermediate determinations, as discussed herein.

[0075] In some embodiments, the controller 116 determines the heater control signal 106 by utilizing one or more formulas, which can be stored in the computer-readable memory 118. In some embodiments, a single formula can used to determine the heater control signal 106 directly from the various inputs. In some embodiments, multiple formulas can be used to make intermediate determination, as discuss herein. In some embodiments, the controller 1 16 can include circuitry that is configured to execute an algorithm to determine the heater control signal 106. In some embodiments, the controller 116 can read various inputs such as the ambient temperature, ambient humidity, target internal temperature 120, window structure aspect 122, property of a heater 124 (e.g., maximum heating power), and/or heater buffer 126), and the controller 116 can determine an a heating power value. The heating power value can be compared to the maximum heating power 124 to get the percentage or proportion of total output power, which can be output as the heater control signal 106.

[0076] In some embodiments, the controller 116 can include computer hardware components (e.g., one or more integrated circuits) that are configured to implement the one or more formulas or similar algorithms for determining the heater control signal 106 based on the various inputs discussed herein.

[0077] In some embodiments, the controller 116 can determine the heater control signal 106 in a using multiple formulas or multiple look-up tables. For example, the controller 116 can determine a dew point value using a first look-up table or a first formula. The controller 116 can determine an estimated temperature for the door window using a second look-up table or a second formula. And the controller can determine the heater control signal 106 based on the estimated dew point and the estimated door window temperature using a third look-up table or a third formula, e.g., which can be configured to drive the heaters 136a-c so that the estimated temperature of the door windows 134a-c is higher than the estimated dew point, thus preventing condensation from forming.

[0078] In some embodiments, the controller 116 calculates or estimates the ambient dew point based on the ambient temperature and the ambient humidity. In some embodiments, the ambient dew point is assumed to also be the estimated dew point at the door windows 134a-c. In some embodiments, the controller 116 can determine an estimated dew point at the one or more door windows 134a-c (which can be different than the ambient dew point) based on the ambient temperature, the ambient humidity, and the first look-up table or the first formula can be configured to account for an expected difference between the ambient environment (e.g., ambient humidity) and the environment inside the refrigeration units 132a-c (e.g., an internal refrigerator humidity), and/or to account for one or more additional variables, such as the target internal refrigeration temperature 120 of the refrigeration units 132a-c. For example, the ambient temperature and the ambient humidity may be used to determine the dew point in the ambient room, and then the target internal temperature of the refrigerator 132a-c or other factors can be used to estimate the dew point on the door windows 134a-c on the refrigeration units 132a-c.

[0079] In some embodiments, the controller 116 also estimates the temperature of the door windows 134a-c, e.g., using a second look-up table or formula. For example, given some combination of the ambient temperature (e.g., measured by the ambient temperature sensor 110), the target internal refrigeration temperature 120 of the refrigeration units 132a-c, the structure of the window 122, the heater property 124, and one or more current or past signals sent to the heaters 136a-c, the temperature at the door windows 134a-c can be estimated using a second look-up table or a second formula. In some embodiments, the heater control signal 106 that is currently being sent to the heaters 136a-c, or that was sent to the heaters based on the immediately prior heater control signal determination can be considered in estimating the temperature of the door windows 134a-c (and can also be considered in determining the heater control signal 106 in various other embodiments disclosed herein). In some embodiments one or more past heater control signals 106 can be stored in the computer readable memory 118 (e.g., in a heater control signal history accessed by the controller 116), and at least some past heater control signals can be used by the controller 116 to estimate the temperature of the door windows 134a-c (and also to determine the heater control signal 106 in various other embodiments disclosed herein). In some embodiments, the controller does not consider the current or past heater control signals 106, and the controller 116 can determine an estimated door window temperature independent of the heater (e.g., an estimated temperature that the door windows 134a-c would have if no heater were used), and the heater control signal 106 can be determined using that estimated temperature value.

[0080] In some embodiments, the controller 116 may compare the dew point (e.g., the ambient dew point or the estimated dew point at the door windows 134a-c) with the estimated temperature at the door windows 134a-c, to determine a proper heater control signal 106 (e.g., using a third look-up table or a third formula). For example, if the estimated temperature of the door windows 134a-c is lower than the estimated dew point at the door windows 134a-c, the controller 116 may determine that adjustments should be made to the heaters 136a-c coupled to the door windows 134a-c in order to bring the estimated temperature of the glass 134a-c at or above the dew point, and the controller 116 may use the third look-up table or a third formula to determine a suitable heater control signal 106 to adjust the heaters 136a-c.

[0081] In some embodiments, one or more additional inputs (e.g., the heating buffer 126 discussed herein) can be considered by the third formula or the third look-up table in determining the heater control signal 106. For example, the heating buffer 126 can indicate how for (e.g., in degrees temperature) above or below the estimated dew point temperature the controller 116 will try to set the estimated door window temperature. For example, if the heating buffer 126 is set to a low value (e.g., 1°F), the controller 116 may configured to adjust heater 136a-c to try and maintain the estimated door window temperature only slightly (e.g., 1°F) above the estimated dew point temperature. As another example, if the heating buffer 126 is set to a higher value (e.g., 4°F), the controller 116 may increase the heater 136a-c power levels to try to maintain estimated door window temperature at a temperature that is above the estimated dew point temperature by a larger amount (e.g., 4°F).

[0082] Many variations are possible. For example, each of the three formulas or look-up tables discussed above can be separated into additional formulas or look-up tables, hi some embodiments, the heater control system can output the estimated dew point or door window temperature using the information output elements 130 (e.g., on a display or to a database for storage).

[0083] In some embodiments, the controller 1 16 can determine the heater control signal 106 without estimating a dew point and/or without estimating a temperature of the door windows 134a-c. For example, in some embodiments, a single look-up table or formula can be used by the controller 116 to determine the heater control signal 106 utilizing the inputs discussed herein (e.g., some combination of the ambient humidity (e.g., measured by the ambient humid sensor 1 14), the ambient temperature (e.g., measured by the ambient temperature sensor 110), the target internal refrigeration temperature 120, the window structure information 122, information regarding a heater property 124 such as a maximum heating capability (e.g., inputted by a user). In some embodiments, additional inputs (e.g., a heater buffer value 126) can be used by the controller 116 to determine the heater control signal 106. In some embodiments, the current heater control signal 106 that is being output by the system 102 and/or some number of prior heater control signals 106 can be used to determine the heater control signal 106, although in some embodiments, no current or past heater control signals 106 are considered by the controller 116 in making the determination of the new heater control signal 106. As discussed herein, various inputs mentioned above can be omitted in some embodiments. By determining the heater control signal 106 without determining an estimated dew point and/or without determining an estimated door window temperature (e.g., using the single formula or single look-up table discussed herein), the heater control signal 106 can be determined using fewer and/or simpler calculations, using fewer and/or simpler formulas or look-up tables, using simpler controller hardware (e.g., one or more integrated circuits). The heater control system 102 can use less memory and/or use less complicated circuitry when the heater control signal 106 is determined without estimating the dew point and/or without estimating the window door temperature.

[0084] Various different formulas and look-up tables can be used to determine the heater output signal 106. For example, a formula or look-up table can be configured to indicate that less heat can be applied (e.g., via the heaters 136a-c) when the ambient temperature reading is relatively high, and that more heat should be applied (e.g., via the heaters 136a-c) when the ambient temperature is relatively low (assuming all other variables stay the same).

[0085] A formula or look-up table can be configured to indicate that less heat can be applied (e.g., via the heaters 136a-c) when the ambient humidity reading is relatively low, and that more heat should be applied (e.g., via the heaters 136a-c) when the ambient humidity is relatively high (assuming all other variables stay the same).

[0086] A formula or look-up table can be configured to indicate that less heat can be applied (e.g., via the heaters 136a-c) when the target temperature in the refrigeration units 132a-c is relatively high, and that more heat should be applied (e.g., via the heaters 136a-c) when the target temperature in the refrigeration units 132a-c relatively low (assuming all other variables stay the same).

[0087] Regarding structural aspects of a window 122, a formula (or look-up table) may be configured to indicate that the amount of heat applied to a two-paned window should be higher than the amount of heat applied to a three-paned window and that the amount (assuming all other variables are constant).

[0088] As another example, regarding heater properties 124 (e.g., maximum power capabilities of the heater), a formula or look-up table may indicate that the power output percentage level should be lower for a heater 136a-c with a high power output capability, and higher for a heater 136a-c with a low power output capability (assuming all other variables are constant). Thus, for example, if a heater 114 with a maximum power of 100 watts were be able to prevent condensation running at 40%, a heater with a maximum power of 80 watts may need to run at 50% to achieve the same level of condensation. In some embodiments, a controller 116 may receive other properties associated with the heater 136a-c, and a look-up table or formula may be utilized accordingly. For example, a look-up table may indicate that different heater control signals should be sent to different models of heaters (even if all other variables are constant).

[0089] As yet another example, regarding heating buffer values 126, a formula (or look-up table) may indicate that the amount of heat to be applied to a window 134a-c should be higher when the buffer 126 is set a high value, whereas the amount of heat should be lower when the buffer 126 is set at a low value (assuming all other variables are constant). The heating buffer value 126 can indicate, for example, an additional amount or percentage of power that will be applied to the heaters 136a-c (e.g., above the amount or percentage of power that would be applied with no heating buffer 126). In some embodiments, the heating buffer 126 can be applied separately from the formula or look-up table that considers to the other inputs (e.g., as a final adjustment before the heater control signal 106 is outputted), or the adjustment of the heating buffer 126 can be incorporated into the formula or look-up table.

[0090] In some embodiments, a look-up table or formula includes various combinations of the described inputs (e.g., structural aspects of a glass window 122, heating buffer value 126, heater property 124, ambient temperature, ambient humidity, and/or target internal refrigerator temperature 120). Accordingly, the controller 116 may utilize a combination of inputs that it receives to look up or formulate the appropriate heater control signal 106 that should be outputted (e.g., sent to the one or more heaters 136a-c), so that the one or more heaters 132a-c apply a suitable amount of heat the glass window 134a-c to reduce or prevent the formation of condensation.

[0091] In some embodiments, one heater control system 102 may send the same heater control signal 106 to the heaters 136a-c for a plurality of refrigeration units 132a-c. For example, for refrigerators in the same room or in the same area within a room, the same ambient temperature signal and the same ambient humidity signal can be used for controlling each of the heaters 136a-c. In addition, the other inputs (e.g., received via user inputs) may be the same for controlling each heater 136a-c (e.g., target internal temperature 120, structural aspect of glass window 122, heater property 124, and/or heater buffer 127), such that the same heater control signal 106 is used for the heaters 136a-c on the plurality of refrigeration units 132a-c. A surface temperature sensor on the surface of a glass window 112 is not used, according to some embodiments. Thus, some embodiments may control condensation on a plurality of refrigeration units 132a-c without the use of individual surface temperature sensors on the door windows 134a-c.

[0092] In some embodiments, the controller 116 sends different heater control signals 106 to the different heaters 136a-c for different refrigeration units 132a-c. For example, two refrigeration units 132a-c in the same room may be associated with different target refrigeration temperatures 120 (e.g., one may be a freezer configured to freeze food items, and the other may be a refrigerator configured to cool food items without freezing them). In such a case, the heater control system 102 may send a different heater control signal 106 to the heaters 136a-c on the two refrigeration units 132a-c, with each heater control signal 106 tailored for each unit.

[0093] If or when the inputs associated with the refrigerator 132a-c change (e.g. ambient settings outside the refrigerator 132a-c), the heater control system 102 may output a new heater control signal 106, in order to properly control condensation on the one or more door windows 134a-c according to the changed inputs.

[0094] In some embodiments, the heater control system 102 receives ambient settings (even if they do not change) according to a certain frequency. This frequency may be at least about once every hour, about once every 30 minutes, about once every 10 minutes, about once every minute, about once every second, about 10 times a second, or more. In some embodiments, each time the heater control system 102 receives ambient settings, the controller 116 can determine a heater control signal 106. In other embodiments, the controller 116 determines a heater control signal 106 only when the ambient settings change, or when the ambient settings change over a certain threshold. In some embodiments, the heater control system 102 outputs the heater control signal 106 to the heater 136a-c every time the controller 116 determines a heater control signal 106. In other embodiments, the heater control system 102 outputs the heater control signal 106 only if it has changed compared to a previous heater control signal, or if it has changed over a certain threshold. When the ambient settings change, the amount of heat applied to the one or more door windows 134a-c adjusts automatically, according to some embodiments of the invention.

[0095] When a user inputs changes or new values (e.g., for the target internal temperature 120, window structure 122, heating buffer value 126, and/or heater property 124), the controller 116 may determine a heater control signal 106 based on the new or changed input. In some embodiments, previous heater control signals 106 can also be utilized to determine the heater control signal to be sent to the heater 136a-c.

[0096] The various illustrative logical blocks, modules, and processes described herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, and states have been described above generally in terms of their functionality. However, while the various modules are illustrated separately, they may share some or all of the same underlying logic or code. Certain of the logical blocks, modules, and processes described herein may instead be implemented monolithically.

[0097] The various illustrative logical blocks, modules, and processes described herein may be implemented or performed by a machine, such as a computer, a processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A processor may be a microprocessor, a controller, microcontroller, state machine, combinations of the same, or the like. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors or processor cores, one or more graphics or stream processors, one or more microprocessors in conjunction with a DSP, or any other such configuration.

[0098] The blocks or states of the processes described herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. For example, each of the processes described above may also be embodied in, and fully automated by, software modules executed by one or more machines such as computers or computer processors. A module may reside in a computer-readable storage medium such as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, memory capable of storing firmware, or any other form of computer-readable storage medium known in the art. An exemplary computer-readable storage medium can be coupled to a processor such that the processor can read information from, and write information to, the computer-readable storage medium. In the alternative, the computer-readable storage medium may be integral to the processor. The processor and the computer-readable storage medium may reside in an ASIC.

[0099] Depending on the embodiment, certain acts, events, or functions of any of the processes or algorithms described herein can be performed in a different sequence, may be added, merged, or left out altogether. Thus, in certain embodiments, not all described acts or events are necessary for the practice of the processes. Moreover, in certain embodiments, acts or events may be performed concurrently, e.g., through multi-threaded processing, interrupt processing, or via multiple processors or processor cores, rather than sequentially.

[0100] Conditional language used herein, such as, among others, "can," "could," "might," "may," "e.g.," and from the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and/or states are included or are to be performed in any particular embodiment.

[0101] While the above detailed description has shown, described, and pointed out novel features as applied to various embodiments, it will be understood that various omissions, substitutions, and changes in the form and details of the logical blocks, modules, and processes illustrated may be made without departing from the spirit of the disclosure. As will be recognized, certain embodiments of the inventions described herein may be embodied within a form that does not provide all of the features and benefits set forth herein, as some features may be used or practiced separately from others. While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosure. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in systems and methods of controlling condensation described herein may be made without departing from the spirit of the disclosure.