WATER HEATER INCLUDING MULTIPLE TEMPERATURE SENSORS

A water heater appliance includes a tank storing water, a first temperature sensor, a second temperature sensor, and a heat source. A method of operating the water heater appliance includes determining a temperature set point of the water within the tank; obtaining a first temperature of the water within the tank via the first temperature sensor; obtaining a second temperature of the water within the tank via the second temperature sensor; determining a heat depletion level of the water indicating a temperature reduction of the water within the tank based on the temperature set point, the first temperature, and the second temperature; and activating the heat source based on the determined heat depletion level.

FIELD OF THE INVENTION

The present subject matter relates generally to water heater appliances, and more particularly to evenly controlling temperatures within water heater appliances.

BACKGROUND OF THE INVENTION

Many households and buildings include water heaters (or hot water tanks) that selectively provide heated water on demand via faucets, showers, and the like. Conventional water heaters include a tank storing a quantity of water, a temperature sensor to sense the temperature of the water, one or more heat sources to provide heat to the water; and piping or tubing to deliver water to and from the tank. The temperature sensor can be provided within the tank (as a thermistor, for example) and may be operably connected with a controller and an actuator for the heat source. According to inputs from the temperature sensor, the heat source is activated when the temperature of the water drops below a predetermined limit.

However, certain drawbacks exist to current water heaters. For instance, the temperature sensor is only capable of determining the temperature of the water in a single location within the tank. Thus, fluctuations within the tank at different areas may not be captured, resulting in inaccurate readings and unnecessary heating or inadequate heating. Moreover, current water heating methods are susceptible to heat stacking, where a portion of the water is markedly hotter than another portion. This may lead to inconsistent supplies of water, which is undesirable to users.

Accordingly, a water heating appliance that obviates one or more of the above-mentioned drawbacks would be beneficial. In particular, a water heater using multiple temperature sensors and curated heating profiles would be useful.

BRIEF DESCRIPTION OF THE INVENTION

In one exemplary aspect of the present disclosure, a water heater appliance is provided. The water heater appliance may include a tank defining a receiving space for storing a quantity of water, a heat source selectively providing heat to the quantity of water, a first temperature sensor provided at a first location on the tank, a second temperature sensor provided at a second location on the tank different from the first location, and a controller operably coupled with the heat source, the first temperature sensor, and the second temperature sensor, the controller being configured to perform an operation. The operation may include determining a temperature set point of the water within the receiving space, obtaining a first temperature of the water within the receiving space via the first temperature sensor, obtaining a second temperature of the water within the receiving space via the second temperature sensor, determining a heat depletion level of the water indicating a temperature reduction of the water within the receiving space based on the temperature set point, the first temperature, and the second temperature, and activating the heat source based on the determined heat depletion level.

In another exemplary aspect of the present disclosure, a method of operating a water heater appliance is provided. The water heater appliance may include a tank storing water, a first temperature sensor, a second temperature sensor, and a heat source. The method may include determining a temperature set point of the water within the tank, obtaining a first temperature of the water within the tank via the first temperature sensor, obtaining a second temperature of the water within the tank via the second temperature sensor, determining a heat depletion level of the water indicating a temperature reduction of the water within the tank based on the temperature set point, the first temperature, and the second temperature, and activating the heat source based on the determined heat depletion level.

DETAILED DESCRIPTION

Turning now to the figures,FIG.1provides a perspective view of a water heater appliance100according to an exemplary embodiment of the present disclosure.FIG.2provides a schematic view of certain components of water heater appliance100. As may be seen inFIGS.1and2, water heater appliance100includes a casing102and a tank (i.e., water tank)112mounted within casing102. Tank112defines an interior volume114for heating water therein.

Water heater appliance100may also include an inlet conduit104and an outlet conduit106that are both in fluid communication with tank112within casing102. As an example, cold water from a water source, such as a municipal water supply or a well, enters water heater appliance100through inlet conduit104(e.g., at an inlet105extending through an upper portion of tank112). From inlet conduit104, such cold water enters interior volume114of tank112wherein the water is heated to generate heated water. Such heated water exits water heater appliance100at outlet conduit106(e.g., supplied through an outlet107at an upper portion of tank112) and, for example, is supplied to a bath, shower, sink, or any other suitable feature.

From line104, water may travel into tank102through a cold water dip tube116that generally extends along a vertical direction V towards the bottom109of tank102. According to some embodiments, dip tube116extends a predetermined distance or length into interior volume or receiving space114of tank102. For instance, a distal outlet end118of dip tube116may be located below a midpoint of tank102along the vertical direction V. Advantageously, cool water supplied via dip tube116may be supplied to a lower portion of tank102, thus allowing a high volume of heated water to be maintained at or near the top of tank102to be easily output to users.

As shown, interior volume114of tank112extends between a top portion108and a bottom portion109along a vertical direction V. Thus, water heater appliance100is generally vertically oriented. Water heater appliance100can be leveled (e.g., such that casing102is plumb in the vertical direction V) in order to facilitate proper operation of water heater appliance100.

In certain embodiments, a drain pan110is positioned at bottom portion109of water heater appliance100such that water heater appliance100sits on drain pan110. Drain pan110sits beneath water heater appliance100along the vertical direction V (e.g., to collect water that leaks from water heater appliance100or water that condenses on an evaporator of water heater appliance100). It should be understood that water heater appliance100is provided by way of example only and that the present subject matter may be used with any suitable water heater appliance.

FIG.2provides a cut away close-up of section A ofFIG.1. As seen inFIG.2, water heater100may include a combustion chamber120in which a gas burner122is centrally located. Gas burner122may be supplied with a gaseous fuel (e.g., propane or natural gas). Air may travel into combustion chamber120through an air intake112in casing102. The resulting mixture of air and gas may be ignited and burned to heat bottom109of tank114and its water contents. Hot combustion gas may exit combustion chamber110through a vent or flue centrally located within tank114. Heat exchange with flue may also help heat water in tank114. A baffle may promote this heat exchange. The gas may then exit water heater100through a vent hood, which may be connected with additional vent piping (not shown). It should be understood that the gas burner described herein is provided by way of example only, and that any suitable heat source (including multiple heat sources) may be incorporated into specific embodiments.

As shown, water heater appliance100includes one or more tank temperature sensors, such as a first temperature sensor130(e.g., lower temperature sensor) and a second temperature sensor132(e.g., upper temperature sensor). Generally, tank temperature sensors130,132are configured for measuring a temperature of water within interior volume114of tank112and can be any suitable temperature sensing device (e.g., in operative communication with a controller150at a corresponding connection pin). For example, one or more tank temperature sensors130,132may be provided as a thermocouple or thermistor. Thus, each temperature sensor130and132may be configured to transmit a voltage signal (e.g., corresponding to a detected temperature) to controller150.

When assembled, one or more tank temperature sensors130,132may be positioned within interior volume114of tank112or may be mounted to tank112outside of interior volume114of tank112. When mounted to tank112outside of interior volume114of tank112, a tank temperature sensor (e.g., first temperature sensor130or second temperature sensor132) can be configured for indirectly measuring the temperature of water within interior volume114of tank112. For example, tank temperature sensors130,132can measure the temperature of tank112and correlate the temperature of tank112to the temperature of water within interior volume114of tank112.

As used herein, “temperature sensor” or the equivalent is intended to refer to any suitable type of temperature measuring system or device positioned at any suitable location for measuring the desired temperature. Thus, for example, temperature sensors130,132may each be any suitable type of temperature sensor, such as a thermistor, a thermocouple, a resistance temperature detector, a semiconductor-based integrated circuit temperature sensors, etc. In addition, temperature sensors130,132may be positioned at any suitable location and may output a signal, such as a voltage, to a controller that is proportional to and/or indicative of the temperature being measured. Although exemplary positioning of temperature sensors is described herein, it should be appreciated that appliance100may include any other suitable number, type, and position of temperature and/or other sensors according to alternative embodiments.

Water heater appliance100further includes a power source or controller150that is configured for regulating operation of water heater appliance100(e.g., by selectively directing electrical power energy from a connected power grid). Controller150is in, for example, operative communication (e.g., electrical communication through one or more conductive wires/busses) with gas burner122and/or tank temperature sensors130,132. Thus, controller150may selectively activate gas burner122in order to heat water within interior volume114of tank112. As an example, controller150may activate/deactivate gas burner122in response to signals from temperature sensors130,132. As will be explained in further detail below, the signals from temperature sensors130,132may be processed and analyzed (e.g., within controller150) to determine a heat depletion level of the water within interior volume114of tank112. For instance, the heat depletion level may indicate a heat reduction of the water relating to usage, idle time, power outages, or the like.

In some embodiments, controller150includes memory (e.g., non-transitive media) and one or more processing devices such as microprocessors, CPUs or the like, such as general or special purpose microprocessors operable to execute programming instructions or micro-control code associated with operation of water heater appliance100. The memory can represent random access memory such as DRAM, or read only memory such as ROM or FLASH. The processor executes programming instructions stored in the memory. The memory can be a separate component from the processor or can be included onboard within the processor. Alternatively, controller150may be constructed without using a microprocessor (e.g., using a combination of discrete analog or digital logic circuitry; such as switches, amplifiers, integrators, comparators, flip-flops, AND gates, and the like) to perform control functionality instead of relying upon software.

Referring now toFIG.3, a schematic illustration of a flowchart of heat depletion levels will be described. As mentioned above, controller150may determine one or more depletion levels of the water within tank114. In detail, controller150may receive signals from each of temperature sensors130,132indicating specific temperatures of the water at each position within tank114. Controller150may then approximate, estimate, or otherwise calculate a general temperature of the water. Based on the general temperature, controller150may determine the heat depletion level of the water. The heat depletion level may indicate or correspond to an amount of heat lost in the water, a rate of heat loss of the water (e.g., due to usage), an anticipated demand of heated or hot water, or the like. Controller150may then direct or perform one or more further algorithms, programs, or methods based on the determined temperatures from temperature sensors130,132.

According to at least one example, controller150compares the temperature determined at second temperature sensor132against a temperature set point (e.g., as input by a user). Controller150may additionally compare the temperature determined at the first temperature sensor130against the temperature set point. Controller150may determine that the water is in a mild depletion state. For instance, the mild depletion state may indicate that a small draw of water has recently been performed (i.e., a small amount of heated water has been removed from tank114). Additionally or alternatively, controller150may determine that the water at or near top108of tank114is still hot (e.g., close to or at the temperature set point, via second temperature sensor132). Controller may then perform a predetermined operation in response to determining the heat depletion level of the water (e.g., an activation of the heat source, emitting a notification, performing a water release operation, etc.).

Now that the general descriptions of an exemplary appliance have been described in detail, a method400of operating an appliance (e.g., water heater appliance100) will be described in detail. Although the discussion below refers to the exemplary method400of operating water heater appliance100, one skilled in the art will appreciate that the exemplary method400is applicable to any suitable domestic appliance capable of performing a water heating operation. In exemplary embodiments, the various method steps as disclosed herein may be performed by controller150and/or a separate, dedicated controller.FIG.4provides a flow chart illustrating a method of operating a water heater appliance. Hereinafter, method400will be described with specific reference toFIG.4.

At step402, method400may include determining a temperature set point of water within a tank. In detail, the controller may determine a temperature input by a user (e.g., via a user interface panel, board, or screen) for a desired water temperature. The user may enter a desired temperature as the temperature set point (e.g., 160° F., 180° F., 200° F., etc.) to be stored in the controller or a memory thereon. The temperature set point may be manually input by the user directly on the appliance, or may be retrieved from a look-up table or predetermined schedule. Additionally or alternatively, the temperature set point may be received wirelessly via a network connection.

At step404, method400may include obtaining a first temperature of the water within the tank via a first temperature sensor. In detail, the controller may receive a signal from a first temperature sensor (e.g., first temperature sensor130) indicating a temperature of water within the tank. The first temperature sensor may indicate a temperature at a particular location within the tank (e.g., an upper location above a tank midpoint or a lower location below the tank midpoint). Accordingly, the first temperature sensor may be located or provided at a first location on the tank (e.g., on an exterior surface of the tank, as described above). According to some embodiments, the controller may analyze the first temperature signal to approximate, extrapolate, or otherwise calculate a temperature of the water within a first predetermined region of the tank.

At step406, method400may include obtaining a second temperature of the water within the tank via a second temperature sensor. In detail, the controller may receive a signal from a second temperature sensor (e.g., second temperature sensor132) indicating a temperature of water within the tank at a second location. The second temperature sensor may indicate a temperature at a particular location within the tank that is different from (e.g., above) the first location. For instance, if the first temperature sensor determines a temperature of a lower region of the tank, the second temperature sensor may determine a temperature of an upper region of the tank (e.g., water within the tank). Accordingly, the second temperature sensor may be located or provided at a second location on the tank (e.g., on an exterior surface of the tank, as described above) spaced apart from the first temperature sensor. According to some embodiments, the controller may analyze the second temperature signal to approximate, extrapolate, or otherwise calculate a temperature of the water within a second predetermined region of the tank.

At step408, method400may include determining a heat depletion level of the water. Such a heat depletion level may indicate a temperature reduction of the water within the tank based on the temperature set point, the first temperature, and the second temperature. In detail, the controller may analyze each of the first temperature (from the first temperature sensor) and the second temperature (from the second temperature sensor) against the temperature set point to determine the heat depletion level. As described above, the heat depletion level may indicate a temperature reduction of the water within the tank (e.g., in the interior volume or receiving space of the tank). According to some embodiments, the heat depletion level is determined based on additional factors apart from temperature differences. For instance, the controller may incorporate one or more variables related to usage, idle time, power outages, water supply, or the like.

The appliance may have the one or more variables stored within a memory (e.g., an onboard memory, a cloud storage, a remote server, etc.). For some examples, the one or more variables include a quick heat offset variable, a change offset variable, a flow offset variable, a low setpoint threshold variable, a depleted level variable, a hysteresis value, a critical depletion drop variable, and the like. Accordingly, in determining the heat depletion level, one or more algorithms may be performed (e.g., by the controller) incorporating one or more of the variables. For instance, the first temperature may be compared against a first value determined according to a first variable. The first variable may be derived from the one or more variables. For another example, the first variable may be based on the temperature set point.

The first value may be determined according to the first variable along with an activation of the water heater appliance (e.g., a request for hot or heated water from a user). For one example, the first temperature is compared against the tank setpoint minus a predetermined offset before the heat source is activated, such that

wherein T1 is the first temperature, TankSPis the tank setpoint, and t1offsetis the predetermined offset before the heat source is activated. The predetermined offset may vary according to the specified tank setpoint, such that the offset is larger when the tank setpoint is higher, for instance. For example, a lookup table or chart is stored within the appliance containing a plurality of predetermined offsets associated with particular tank setpoints. However, it should be understood that the equation given above is merely exemplary and that additional variables may be included or changed according to specific embodiments.

Similarly, the second value may be determined according to the second variable along with the activation of the water heater appliance. For another example, the second temperature is compared against the tank setpoint minus a variation variable, such that

wherein T2 is the second temperature, TankSPis the tank setpoint, and X is the variation variable. X may be adjusted according to the specific setpoint of the tank. For instance, X may proportionately increase as the tank setpoint increases. Again, it should be understood that the equation given above is merely exemplary and that additional variables may be included or changed according to specific embodiments.

Upon comparing the first and second temperatures against the first and second values, respectively, a heat depletion level may be determined. For another example, if the appliance determines that the first temperature is less than the first value by at least a first predetermined amount, and the second temperature is less than the second value by at least a second predetermined amount, a mild heat depletion level may be determined and appropriately stored within the appliance. For instance, a virtual flag may be set within the controller indicating that the mild heat depletion level has been determined. One or more responsive actions may then be taken in response to the determination of the appropriate heat depletion level (e.g., according to the flag setting). For instance, as will be described below, the controller may initiate an activation of the heat source based on the determined heat depletion level. Additionally or alternatively, the controller may perform a controlled release of water or addition of water according to the determined heat depletion level.

Moreover, the critical heat depletion level and severe heat depletion levels may be determined according to similar methods. For another example, the first temperature is less than a lower temperature limit and the second temperature is below the tank setpoint minus the variation variable. The severe heat depletion level may thus be determined and appropriately stored within the appliance. Likewise, the appropriate virtual flag may be set within the controller to initiate the proper responsive action according to the severe heat depletion level.

At step410, method400may include activating the heat source based on the determined heat depletion level. In detail, the responsive action may include activating the heat source (e.g., the gas burner). In some instances, the heat source may be activated according to a particular power level. For example, in the case of the severe heat depletion level (e.g., a temperature loss above a certain level, a rate of heat loss above a certain level, etc.), the heat source may be activated at a maximum power level (e.g., high gas supply, high air intake, etc.). However, according to some embodiments, the heat source is only operational at a single power level. The responsive action may include additional steps, such as limiting an output of water (e.g., restricting a water pressure after a predetermined amount is output), sending an alert to a user, or the like.

The appliance (e.g., the controller) may continue to monitor the first and second temperatures at the first and second temperature sensors (e.g., while the heat source is active). For instance, the controller may determine that the heat depletion level has transitioned from one of the mild heat depletion level, the critical heat depletion level, or the severe heat depletion level to the standby level while the heat source is active. Similar to the equations given above, the first and second temperatures may respectively be compared against first and second values (e.g., determined according to the first and second variables). Accordingly, the heat depletion level may be regularly monitored according to the temperature setpoint, the first temperature, and the second temperature to determine appropriate responsive actions. Thus, when it is determined that the heat depletion level has returned to the standby mode, the heat source may be deactivated.