Patent Description:
A potable water supply for an aircraft is generally filled while the aircraft is on the ground. This can mean the potable water may be sourced from several different geographic locations. Different geographic locations provide water of varying levels of hardness, meaning different concentrations of hard minerals dissolved in the water. Hard water (i.e., water with high concentrations of hard minerals) can create scale buildup in the aircraft beverage making devices, particularly, in devices that heat the water and/or create steam. Scale buildup tends to be especially harmful in devices that employ inline heaters, as the scale buildup may restrict the flow of the water through the fluid lines/conduits. Hard water can also lead to scale buildup on the liquid control solenoids downstream of the device heaters. <CIT> discloses a beverage maker, in which the time t1 to reach a desired temperature T2 is recorded. The recorded time t1 is then compared to a reference time t2; when the difference is above a tolerance time tt, then this is regarded as an indication of a scale buildup.

Disclosed herein is a beverage maker. The beverage maker comprises a heating system, a temperature sensor operably coupled to the heating system, a controller configured to receive a measured temperature signal from the temperature sensor, and a tangible, non-transitory computer-readable storage medium. The tangible, non-transitory computer-readable storage medium has instructions stored thereon for that, in response to execution by the controller, cause the controller to perform operations, which comprise receiving, by the controller, a series of measured temperature signals from the temperature sensor; calculating, by the controller, a change in temperature using the series of measured temperature signals; calculating, by the controller, an efficiency of the heating system based on the change in temperature; estimating, by the controller, a scale buildup based on the efficiency of the heating system; and storing, by the controller, at least one of the estimated scale buildup or the efficiency of the heating system in a heating system performance database.

Calculating, by the controller, the efficiency of the heating system based on the change in temperature comprises determining, by the controller, an expected change in temperature using a system thermal model; and comparing, by the controller, the change in temperature to the expected change in temperature.

In various embodiments, calculating, by the controller, the efficiency of the heating system based on the change in temperature further comprises accessing, by the controller, previous heating system performance data stored in the heating system performance database; and comparing, by the controller, the change in temperature to the previous heating system performance data stored.

In various embodiments, a display device is operably coupled to the controller, and the operations further comprise commanding, by the controller, the display device to display the estimated scale buildup.

In various embodiments, a display device is operably coupled to the controller, and the operations further comprise determining, by the controller, an estimated service life of the heating system; and commanding, by the controller, the display device to display the estimated service life.

In various embodiments, a display device is operably coupled to the controller, and the operations further comprise: determining, by the controller, if the estimated scale buildup is impacting a performance of the beverage maker; and commanding, by the controller, the display device to display a maintenance required alert, if the estimated scale buildup is impacting the performance of the beverage maker.

In various embodiments, determining, by the controller, if the estimated scale buildup is impacting the performance of the beverage maker comprises comparing, by the controller, the efficiency of the heating system to a threshold efficiency.

In various embodiments, a flow rate sensor is operably coupled to the heating system. The flow rate sensor is configured to measure a rate of flow of fluid through the heating system. The controller may be configured to receive a flow rate measurement signal from the flow rate sensor and calculate the efficiency of the heating system using the flow rate measurement signal.

In various embodiments, the controller is configured to receive energy input data. The controller may calculate the efficiency of the heating system using the energy input data.

An article of manufacture is also disclosed herein. The article includes a tangible, non-transitory computer-readable storage medium having instructions stored thereon for detecting and monitoring scale buildup in a beverage maker. The instructions, in response to execution by a controller, cause the controller to perform operations, which comprise receiving, by the controller, a series of measured temperature signals from a temperature sensor operably coupled to a heating system of the beverage maker; determining, by the controller, a change in temperature using the series of measured temperature signals; calculating, by the controller, an efficiency of the heating system based on the change in temperature; estimating, by the controller, a scale buildup based on the efficiency of the heating system; and storing, by the controller, at least one of the estimated scale buildup or the efficiency of the heating system in a heating system performance database.

In various embodiments, calculating, by the controller, the efficiency of the heating system based on the change in temperature further comprises: accessing, by the controller, previous heating system performance data stored in the heating system performance database; and comparing, by the controller, the change in temperature to the previous heating system performance data stored.

Calculating, by the controller, the efficiency of the heating system based on the change in temperature comprises: determining, by the controller, an expected change in temperature using a system thermal model; and comparing, by the controller, the change in temperature to the expected change in temperature.

In various embodiments, the operations further comprise commanding, by the controller, a display device to display the estimated scale buildup. In various embodiments, the operations further comprise determining, by the controller, an estimated service life of the heating system; and commanding, by the controller, a display device to display the estimated service life.

In various embodiments, the operations further comprise commanding, by the controller, the display device to display a maintenance required alert if the efficiency of the heating system is less than a threshold efficiency. In various embodiments, the operations further comprise determining, by the controller, a descaling operation has been performed; and deleting, by the controller, the previous heating system performance data from the heating system performance database.

A method for detecting and monitoring scale buildup in a beverage maker is also disclosed herein. The method comprises the step of receiving, by a controller, a series of measured temperature signals from a temperature sensor operably coupled to a heating system of the beverage maker; determining, by the controller, a change in temperature using the series of measured temperature signals; calculating, by the controller, an efficiency of the heating system based on the change in temperature; estimating, by the controller, a scale buildup based on the efficiency of the heating system; and storing, by the controller, at least one of the estimated scale buildup or the efficiency of the heating system in a heating system performance database.

Calculating, by the controller, the efficiency of the heating system based on the change in temperature further comprises accessing, by the controller, previous heating system performance data stored in the heating system performance database; determining, by the controller, an expected change in temperature using a system thermal model. The method further includes comparing, by the controller, the change in temperature to the expected change in temperature.

In various embodiments, the method may further comprise determining, by the controller, a descaling operation has been performed; and deleting, by the controller, the previous heating system performance data from the heating system performance database.

In various embodiments, the method may further comprise receiving, by the controller, a flow rate measurement signal from a flow rate sensor configured to measure a flow rate of a heat exchanger fluid through the heating system; receiving, by the controller, energy input data; and determining, by the controller, the change in temperature using the series of measured temperature signals, the flow rate measurement signal, and the energy input data.

A more complete understanding of the present disclosure, however, may best be obtained by referring to the detailed description and claims when considered in connection with the drawing figures.

The detailed description of exemplary embodiments herein makes reference to the accompanying drawings, which show exemplary embodiments by way of illustration. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, it should be understood that other embodiments may be realized and that logical changes and adaptations in design and construction may be made in accordance with this disclosure and the teachings herein without departing from the scope of the claims.

Disclosed herein, according to various embodiments are systems and methods for detecting and predicting scale buildup in a beverage maker. Although details and examples are included herein pertaining to implementing the systems and methods in a beverage maker for an aircraft, the present disclosure is not necessarily so limited, and thus aspects of the disclosed embodiments may be adapted for performance in a variety of other industries. As such, numerous applications of the present disclosure may be realized.

In various embodiments, and with reference to <FIG>, an aircraft <NUM> may include galley area <NUM>. The galley area <NUM> may include a beverage maker <NUM>. Beverage maker <NUM> may include an espresso machine, a cappuccino machine, a coffee machine, a water heater, and/or similar machine, or combinations thereof. <FIG> illustrates a schematic of beverage maker <NUM>. Beverage maker <NUM> receives water <NUM> from a potable water source <NUM>. Potable water source <NUM> may be located on aircraft <NUM> (<FIG>). Beverage maker <NUM> may include one or more pump(s) <NUM>. Pump(s) <NUM> is/are configured to pump water <NUM> from a potable water source <NUM> through various components of beverage maker <NUM>. In various embodiments, pump(s) <NUM> may be located outside beverage maker <NUM>. For example, pump(s) <NUM> may be coupled between an output of potable water source <NUM> and a potable water input of beverage maker <NUM>. In various embodiments, pressurization of the potable water system may be performed by means other than pumps, e.g., bleed-off pressure from jet engines.

Beverage maker <NUM> includes a heating system <NUM>. Heating system <NUM> is configured to increase a temperature of the water <NUM> received from potable water source <NUM> and provided to at least one of a brew system <NUM> and/or a froth system <NUM> of beverage maker <NUM>.

With reference to <FIG>, a cross-section view of an inline heat exchanger <NUM> of heating system <NUM> is illustrated. Inline heat exchanger <NUM> includes a heating element <NUM> and a thermally conductive block <NUM> (also referred to herein as a heating block) located about the heating element <NUM>. In various embodiments, thermally conductive block <NUM> is formed of a metal or metal alloy. For example, thermally conductive block <NUM> may be formed of aluminum, copper, stainless steel, or any other suitably conductive material. A conduit <NUM> is located through thermally conductive block <NUM>. Conduit <NUM> is thermally coupled to thermally conductive block <NUM>. In various embodiments, conduit <NUM> is helically formed about heating element <NUM>. While conduit <NUM> is illustrated as formed through thermally conductive block <NUM>, in various embodiments, conduit <NUM> may be located about the outer circumferential surface of thermally conductive block <NUM>. In other embodiments, conduit <NUM> may be a channel defined by thermally conductive block <NUM> (i.e., water <NUM> may be in direct contact with thermally conductive block <NUM>).

During operation, potable water <NUM> from potable water source <NUM> (<FIG>) flows into an inlet <NUM> of thermally conductive block <NUM>. Water <NUM> flows through conduit <NUM> and about heating element <NUM>. Thermally conductive block <NUM> conducts heat generated by heating element <NUM> into water <NUM>, thereby increasing the temperature of water <NUM> as it flows through conduit <NUM>. Water <NUM> exits thermally conductive block <NUM> at outlet <NUM>. In this regard, thermally conductive block <NUM> and heating element <NUM> are configured to heat water <NUM> as it flows through conduit <NUM>.

While <FIG> illustrates an inline heat exchanger <NUM>, it is further contemplated and understood that, in various embodiments, heating system <NUM> may include a reservoir heater. <FIG> illustrates a reservoir heater <NUM>. In various embodiments, beverage maker <NUM> may include reservoir heater <NUM> in place of, or in addition to, inline heat exchanger <NUM> (<FIG>). Reservoir heater <NUM> includes a water reservoir <NUM> and one or more heating element(s) <NUM> located in water reservoir <NUM>. Heating elements <NUM> comprise immersion heaters that are in direct contact with the fluid to be heated. For example, heating element <NUM> may include a resistance heating element (e.g., a nichrome heater core) embedded in a conductive thermal mass (i.e., a thermally conductive electrical insulator) with a metal casing located about the conductive thermal mass. The metal casing is in direct contact with the water <NUM> in the water reservoir <NUM>.

During operation, potable water <NUM> from potable water source <NUM> (<FIG>) flows into an input <NUM> of water reservoir <NUM>, heat generated by heating element(s) <NUM> is conducted into water <NUM>, thereby increasing the temperature of water <NUM>. Water <NUM> exits water reservoir <NUM> via an outlet <NUM>. While an inline heat exchanger (<FIG>) and a reservoir heater have been described, it is contemplated and understood that beverage maker <NUM> may include other types of fluid heaters. For example, in various embodiments, heating system <NUM> may comprise a fluid to fluid heat exchanger.

Returning to <FIG>, in accordance with various embodiments, beverage maker <NUM> further includes a brew system <NUM> and/or a froth system <NUM>. Brew system <NUM> and froth system <NUM> are each configured to receive heated fluid (e.g., water or steam) output from heating system <NUM>. Brew system <NUM> may be configured to brew (e.g., mix heated water <NUM> with) coffee, tea, espresso, etc. Froth system <NUM> may be configured to combine steam and milk to form froth.

In accordance with various embodiments, beverage maker <NUM> includes a scale detection and monitoring system <NUM>. As described in further detail below, scale detection and monitoring system <NUM> is configured to monitor scale buildup in heating system <NUM>. Scale detection and monitoring system <NUM> determines the scale buildup and efficiency of heating system <NUM> based on a change in temperature in at least one of the heating block of heating system <NUM> or of the water <NUM> output from heating system <NUM>. In various embodiments, scale detection and monitoring system <NUM> may also use a flow rate of water <NUM> through conduit <NUM> and/or an amount of energy input into heating system <NUM> to determine the scale buildup and heating system efficiency.

I In accordance with various embodiments, scale detection and monitoring system <NUM> incudes a controller <NUM>. Controller <NUM> may include a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or some other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. A tangible, non-transitory computer-readable storage medium <NUM> may be in communication with controller <NUM>. The storage medium <NUM> may comprise any tangible, non-transitory computer-readable storage medium known in the art. The storage medium <NUM> has instructions stored thereon that, in response to execution by controller <NUM>, cause controller <NUM> to perform operations related to detecting and monitoring scale buildup in beverage maker <NUM>.

Mineral deposits (i.e., scale) on the walls of conduit <NUM> (<FIG>) and/or on the walls of heating element(s) <NUM> (<FIG>) can act as an insulator and decrease the efficiency of heat transfer to water <NUM>. Scale buildup on the walls of conduit <NUM> (<FIG>) and/or on the walls of the inlet <NUM> and/or outlet <NUM> (<FIG>) can also impede fluid flow, which also tends to decrease heating system efficiency. Controller <NUM> may be configured to detect and monitor scale buildup based on signals received from a sensor unit <NUM> of heating system <NUM>.

With combined reference to <FIG>, and <FIG>, in accordance with various embodiments, sensor unit <NUM> includes at least one temperature sensor <NUM> (e.g., resistive temperature device) configured to send measured temperature signals <NUM> to controller <NUM>. In various embodiments, sensor unit <NUM> includes a heating block temperature sensor 126a operably coupled to the heating block <NUM> in <FIG>. Heating block temperature sensor 126a is configured to measure a temperature of the heating block <NUM>. In various embodiments, sensor unit <NUM> includes a liquid temperature sensor 126b located in water reservoir <NUM> in <FIG>. Liquid temperature sensor 126b is configured to measure a temperature of the water <NUM> in water reservoir <NUM>. In various embodiments, , sensor unit <NUM> includes one or more temperature sensors immersion heater temperature sensors 126c operably coupled to heating elements <NUM> in water reservoir <NUM>. Heater temperature sensors 126c are configured to measure a temperature of heating elements <NUM> In various embodiments, sensor unit <NUM> includes an inlet temperature sensor <NUM>Inlet configured to measure temperature of the water <NUM> at the inlet <NUM>, <NUM> of the heating system <NUM> and an outlet temperature sensor <NUM>Outlet configured to measure a temperature of the water <NUM> at the outlet <NUM>, <NUM> of the heating system <NUM>.

In various embodiments, sensor unit <NUM> may also include one or more flow sensor(s) <NUM>, configured to send measured flow rate signals <NUM> to controller <NUM>. The flow sensor(s) <NUM> may be configured to measure at a flow rate (e.g. volume of fluid per unit of time) of the water <NUM> through conduit <NUM> and/or output from water reservoir <NUM> (e.g., the flow rate of water <NUM> through heating system <NUM>).

With additional reference to <FIG>, a method <NUM> for detecting and monitoring scale buildup in a beverage maker is illustrated. The steps of method <NUM> may be performed by controller <NUM>, with momentary reference to <FIG>, to detect and monitor scale buildup in beverage maker <NUM>. Method <NUM> may begin in response to at least one of a brew operation or a froth operation being initiated (step <NUM>). Stated differently, step <NUM> may comprise controller <NUM> receiving a signal indicating that a brew operation or a froth operation has been initiated. Initiating a brew operation or a froth operation may cause water <NUM> from potable water source <NUM> to flow into heating system <NUM>.

In accordance with various embodiments, controller <NUM> may start a scale detection process in response to determining the brew operation or the froth operation has been initiated (step <NUM>). In response to starting the scale detection process, controller <NUM> may begin receiving measured temperature signals <NUM> from temperature sensor(s) <NUM> (step <NUM>). Controller <NUM> calculates a change in temperature (ΔT) using the measured temperature signals <NUM> (step <NUM>). For example, controller <NUM> may calculate ΔT based on measured temperature signals <NUM> from heating block temperature sensor 126a and/or based on measured temperature signals <NUM> from liquid temperature sensor 126b and/or based on measured temperature signals <NUM> received from inlet temperature sensor <NUM>Inlet and outlet temperature sensor <NUM>Outet. In various embodiments, step <NUM> may comprise controller <NUM> calculating a rate of ΔT (e.g., the change in temperature relative a duration of time). In various embodiments, step <NUM> may comprise controller <NUM> calculating a duration of time to reach a threshold ΔT. For example, controller <NUM> may calculate the duration of time it takes for the temperature of the heating block to decrease by, for example, <NUM>° Celsius (C), or <NUM>° C, or any other desired ΔT. In various embodiments, controller <NUM> may calculate the duration of time it takes for the outlet water temperature to be <NUM>° C, <NUM>° C, or any other desired ΔT greater than the inlet water temperature.

Controller <NUM> may then calculate an efficiency of heating system <NUM> based on ΔT (step <NUM>). Step <NUM> may comprise controller <NUM> determining an expected ΔT and calculating a difference between the expected ΔT and the ΔT calculated in step <NUM> (referred to herein as "actual ΔT"). In other words, actual ΔT is calculated based on measured temperature signals <NUM> and then actual ΔT is compared to expected ΔT. In various embodiments, controller <NUM> may calculate the efficiency as a percentage of expected ΔT. In this regard, controller <NUM> may calculate the efficiency by dividing actual ΔT by expected ΔT (actual ΔT/expected ΔT). Controller <NUM> determines an expected ΔT using a system thermal model <NUM>, which may be stored in storage medium <NUM> (or any other memory accessible to controller <NUM>). System thermal model <NUM> is modelled to the specifications of heating system <NUM>. In this regard, system thermal model <NUM> may model expected ΔT based on the specifications of the heating unit of heating system <NUM> (e.g., the material, volume, and/or thermal conductivity of the heating block, the diameter of the conduit, the specification of heating elements <NUM>, <NUM>, etc.) and the energy supplied to heating system <NUM> (e.g., the energy supplied to heating elements <NUM>, <NUM>).

In various embodiments, step <NUM> may further comprise controller <NUM> comparing ΔT to previous heating system performance data <NUM>, stored in a heating system performance database <NUM>. Heating system performance database <NUM> may be located in storage medium <NUM> (or any other memory accessible to controller <NUM>). For example, previous heating system performance data <NUM> includes ΔTs and/or heating system efficiencies (e.g., actual ΔT/expected ΔT) calculated during previous heating system scale detection processes performed by controller <NUM>. Controller <NUM> may compare the current ΔT to the ΔTs calculated during previous heating system scale detection processes and/or controller <NUM> may compare a current ratio of actual ΔT to expected ΔT to ratios of actual ΔT to expected ΔT calculated during previous heating system scale detection processes. In this regard, step <NUM> may include controller <NUM> determining a trend in the efficiency of heating system <NUM>.

Controller <NUM> may estimate a scale buildup within heating system <NUM> (step <NUM>). Controller <NUM> may estimate the scale buildup based on the heating system efficiency calculated in step <NUM>. For example, a decrease in efficiency correlates to an increase in scale buildup. Step <NUM> may further include controller <NUM> estimating a remaining service life of heating system <NUM> based on the trend in the efficiency and/or based on a rate at which scale buildup is increasing. For example, controller <NUM> may estimate a number of brewing operations and/or frothing operations that can be performed and/or a duration of time (minutes, hours, etc.) heating system <NUM> may be operated before significantly impacting performance of beverage maker <NUM>. For example, controller <NUM> may estimate a number of brewing operations and/or frothing operations that can be performed before the efficiency (determined in step <NUM>) will be less than a threshold efficiency (e.g., <NUM>% efficiency, <NUM>% efficiency, etc.).

In accordance with various embodiments, controller <NUM> may command a display device <NUM> of beverage maker <NUM> to display at least one of the estimated scale buildup or the estimated remaining service life. For example, the estimated scale buildup may be displayed as percentage of a maximum allowable scale buildup. The maximum allowable scale buildup may correlate to a scale buildup that would result in the efficiency of heating system <NUM> being less than the threshold efficiency. For example, controller <NUM> may command display device <NUM> to display that the scale buildup is at <NUM>% and/or that <NUM> more brewing operations remain, and/or that <NUM> more frothing operation remain, and/or that heating system has <NUM> hours remaining. It is understood that the previous values are for purposes of example only, and that display device <NUM> may display any message, symbol, picture, text, etc. configured to convey the estimated scale buildup and/or the estimated remaining service life). Displaying the current scale buildup or remaining service life allows the aircraft operator to better plan for and schedule maintenance (e.g., a descaling) of beverage maker <NUM>. Allowing the aircraft operator to schedule maintenance and/or scale removal decreases a probability that beverage maker <NUM> will be unavailable during flight.

In accordance with various embodiments, controller <NUM> stores the heating system performance data (e.g., the heating system efficiency calculated in step <NUM>, the scale buildup estimated in step <NUM>, and/or the service life estimated in step <NUM>) for use in subsequent scale detection processes (step <NUM>). The heating system performance data may be stored in heating system performance database <NUM>.

In accordance with various embodiments, controller <NUM> determines whether the scale buildup estimated in step <NUM> is impacting a performance of beverage maker <NUM> (step <NUM>). Controller <NUM> may determine the scale buildup is impacting the performance of beverage maker <NUM> if the efficiency (determined in step <NUM>) is less than a threshold efficiency (e.g., less than <NUM>% efficient, less than <NUM>% efficient, etc.). If controller <NUM> determines the scale buildup is impacting the performance of beverage maker <NUM>, controller <NUM> commands display device <NUM> to output a maintenance needed alert (step <NUM>). The maintenance needed alert may convey to an operator that beverage maker <NUM> needs to be descaled and that beverage maker <NUM> should be scheduled for service.

In accordance with various embodiments, controller <NUM> may be configured to perform a history reset (step <NUM>) and delete previous heating system performance data <NUM> from heating system performance database <NUM> (step <NUM>). Controller <NUM> may perform the history reset in response to a descaling operation being performed. Controller <NUM> may perform the history reset and data deletion (steps <NUM>, <NUM>) in response to receiving a reset signal. The reset signal may be sent manually. For example, the reset signal may be sent in response to maintenance personnel pressing a button, or other input on beverage maker <NUM>, after performing the descaling operation. In various embodiment, controller <NUM> may perform the history reset and data deletion (steps <NUM>, <NUM>) in response to determining the estimated scale buildup (determined in step <NUM>) is sufficiently less than the estimated scale buildup from the previous (or last) heating system scale detection process. In this regard, the current heating system scale detection process may be referred to as "n," the last heating system scale detection process being "n-<NUM>," the second to last heating system scale detection process being "n-<NUM>," and so on. Controller <NUM> may perform the history reset and data deletion (steps <NUM>, <NUM>) if the difference between estimated scale buildup from the last heating system scale detection process ((n-<NUM>)Estirnated_Scale_Buildup) and the estimated scale buildup from the current heating system scale detection process (nEstimated_Scale_Buildup) is greater than a threshold difference (i.e., is nEstimated_Scale_Buildup - (n-<NUM>)Estimated_Scale_Buildup > threshold difference).

With reference to <FIG>, a method <NUM> for detecting and monitoring scale buildup is illustrated. The steps of method <NUM> may be performed by controller <NUM> to detect and monitor scale buildup in beverage maker <NUM>. Method <NUM> may include steps similar to method <NUM> in <FIG>. In this regard, elements with like element numbering, as depicted in <FIG>, are intended to be the same and will not necessarily be repeated for the sake of brevity.

In accordance with various embodiments, controller <NUM> may also receive measured flow rate signals <NUM> from flow rate sensor(s) <NUM> (step <NUM>). In various embodiments, controller <NUM> may also receive energy input data (step <NUM>). Energy input data may comprise a duration of time the heating system is powered on, a current and/or voltage provided to heating system <NUM> (e.g., current and/or voltage supplied to heating elements <NUM>, <NUM>), or similar energy data related to operating of heating system <NUM>. Controller <NUM> may calculate the heating system efficiency (step <NUM>) using the calculated/actual ΔT (step <NUM>) along with the measured flow rate signals <NUM> and/or the energy input data. Using the flow rate data along with the energy input data may increase the accuracy of the heating system efficiency calculation and/or the estimated scale buildup and remaining service life calculations.

Moreover, where a phrase similar to "at least one of A, B, or C" is used in the claims, it is intended that the phrase be interpreted to mean that A alone may be present in an embodiment, B alone may be present in an embodiment, C alone may be present in an embodiment, or that any combination of the elements A, B and C may be present in a single embodiment; for example, A and B, A and C, B and C, or A and B and C.

Claim 1:
A beverage maker (<NUM>), comprising
a heating system (<NUM>);
a temperature sensor (<NUM>) operably coupled to the heating system (<NUM>);
a controller (<NUM>) configured to receive measured temperature signals from the temperature sensor; and
a tangible, non-transitory computer-readable storage medium having instructions stored thereon for that, in response to execution by the controller, cause the controller to perform operations comprising:
receiving, by the controller, a series of measured temperature signals from the temperature sensor;
calculating, by the controller, a change in temperature using the series of measured temperature signals;
calculating, by the controller, an efficiency of the heating system based on the change in temperature;
estimating, by the controller, a scale buildup based on the efficiency of the heating system; and
storing, by the controller, at least one of the estimated scale buildup or the efficiency of the heating system in a heating system performance database;
wherein calculating, by the controller, the efficiency of the heating system based on the change in temperature comprises:
determining, by the controller, an expected change in temperature using a system thermal model; and
comparing, by the controller, the change in temperature to the expected change in temperature.