Hot water heater systems and methods for monitoring electronic mixing valves

Hot water heater systems and methods for monitoring electronic mixing valves of hot water heater systems are provided. An electronic mixing valve provides a flow of water in a mixed output line. A method includes determining whether an output flow event is occurring, determining a first temperature value for water in the mixed output line when the output flow event is occurring, comparing the first temperature value to a setpoint temperature value to obtain a first temperature error value when the output flow event is occurring, and generating a failure signal when the first temperature error value is outside of a predetermined error range and the output flow event is occurring.

FIELD OF THE INVENTION

The present disclosure relates generally to hot water heater systems, and more particularly to methods for monitoring electronic mixing valves of hot water heater systems.

BACKGROUND OF THE INVENTION

Mixing valves in hot water heater systems are generally used to increase the hot water capacity of hot water tanks of the hot water heaters. By increasing the temperature of the hot water in the hot water tank, and then mixing the hot water flow from the hot water tank with cold water in a mixing valve, the realized capacity of the hot water tank is increased.

U.S. Patent Application Publication No. 2014/0026970, filed Jan. 30, 2014, entitled “Electronic Mixing Valve in Standard Hot Water Heater”, and which is incorporated by reference in its entirety herein, discloses electronic mixing valves for use in hot water heaters. Electronic mixing valves generally provide improved control over the temperature of the water delivered from associated hot water heaters relative to, for example, mechanical mixing valves.

However, improvements could be made to presently known methods for controlling such electronic mixing valves. For example, one concern is that if an electronic mixing valve fails, water having a different temperature than desired by a user can be inadvertently provided to the user. This is of particular concern in cases wherein the temperature of the water stored in the tank is increased. If the electronic mixing valve fails, water that is significantly hotter than a desired temperature could be provided to the user, causing discomfort and potentially injuring the user. Accordingly, improved hot water heater systems and methods for monitoring electronic mixing valves are desired. In particular, improvements which monitor for indications if electronic mixing valve failure would be advantageous.

BRIEF DESCRIPTION OF THE INVENTION

In accordance with one embodiment of the present disclosure, a method for monitoring an electronic mixing valve of a hot water heater system is disclosed. The electronic mixing valve provides a flow of water in a mixed output line. The method includes determining whether an output flow event is occurring, determining a first temperature value for water in the mixed output line when the output flow event is occurring, comparing the first temperature value to a setpoint temperature value to obtain a first temperature error value when the output flow event is occurring, and generating a failure signal when the first temperature error value is outside of a predetermined error range and the output flow event is occurring.

In accordance with another embodiment of the present disclosure, a hot water heater system is disclosed. The hot water heater system includes a hot water tank having a cold water inlet line and a hot water outlet line, an electronic mixing valve fluid coupled to the cold water inlet line and the hot water outlet line, a mixed output line fluidly coupled to the electronic mixing valve, and a controller operatively coupled to the electronically controlled mixing valve. The controller is configured for determining whether an output flow event is occurring, determining a first temperature value for water in the mixed output line when the output flow event is occurring, comparing the first temperature value to a setpoint temperature value to obtain a first temperature error value when the output flow event is occurring, and generating a failure signal when the first temperature error value is outside of a predetermined error range and the output flow event is occurring.

DETAILED DESCRIPTION OF THE INVENTION

Referring toFIG. 1, an exemplary hot water heater system100and hot water heater10therefor are provided. As shown, the hot water heater system100generally includes hot water heater10, an electronic mixing valve20and a controller30. In the embodiment ofFIG. 1, the hot water heater10includes a reservoir or water storage tank12for storing water and a heat source14for heating the water stored in the tank12. The tank12and heat source14are generally housed within a casing11of the hot water heater10. In exemplary embodiments, the hot water heater10is a heat pump water heater, and the heat source14is thus a heat pump heating element. It should be understood, however, that the present disclosure is not limited to heat pump water heaters, and rather that any suitable water heaters may be utilized. Further, any suitable heat sources14, including gas burners, heat pumps, electric resistance elements, microwave elements, induction elements, or any other suitable heating element or combinations thereof, may be utilized. The hot water heater system10includes an inlet34for receiving water from inlet line16for delivery into the tank12. The water in the inlet line16is typically described as non-heated or “cold” water. The inlet line16is typically part of or connected to a water supply line for a home or building. The hot water heater system10also includes an outlet line18for supplying water from the tank12that has been heated to a pre-determined temperature, generally referred to herein as hot water. In the embodiment shown inFIG. 1, the outlet line18is coupled to the mixing valve20. The mixing valve20may receive non-heated water from the inlet line16and heated water from the outlet line18and may mix the heated water with the non-heated water to reduce the temperature of the water from the mixing valve20that is delivered to the plumbing system40. The mixing valve20includes a mixed outlet or output line22that delivers the heated water resulting from the mixing to the portions of the plumbing system40to which the hot water heater10is connected, generally referred to herein as the hot water portions of the hot water system. The plumbing system40can be part of a residential, commercial or other water plumbing system that incorporates a hot water heater.

As shown inFIG. 1, in these embodiments, the mixing valve20is fluidly connected to the inlet line16and the outlet line18. The mixing valve20is coupled to the plumbing system40via the mixed output line22. In one embodiment, the mixing valve20is an electronically controlled mixing valve and can include for example, a solenoid operated water valve and a gear or motor driven water valve. In alternate embodiments, any suitably controlled water mixing valve can be utilized to provide precise flow control such as for example, a servo or stepper motor coupled with a valve.

In exemplary embodiments, the mixing valve is disposed within the casing11. Alternatively, however, the mixing valve may be external to the hot water heater10.

In the embodiment shown inFIG. 1, the controller30is an electronic controller that is operatively coupled to the hot water heater10and the mixing valve20. Controller30can include or be operatively coupled to, or be in communication with, one or more processor(s) that are operable to monitor and control the flow of hot water from the hot water tank12and heated water from the mixing valve20, as well as execute the processes that are generally described herein. In one embodiment the controller30can include or receive machine-readable instructions that are executable by one or more processors or other suitable processing device(s). The processor(s) can include program code to perform particular tasks and/or data manipulations, as are generally described herein. In one embodiment, the processor(s) can include or be coupled to a memory and input/output devices. The memory typically includes both non-volatile memory, such as semiconductor type random access memory, and non-volatile memory such as a magnetic computer disk.

In one embodiment, the controller30is operatively coupled to and between, and is communication with, the hot water heater10and the mixing valve20. The controller30can also include or be coupled to a user interface32. In one embodiment, the controller30and user interface32form part of a home energy management (HEM) system. The user interface32can comprise any suitable control or display that will allow a user to program, set and adjust the functions and settings of the hot water heater system100, as are generally described herein. In one embodiment, the user interface32comprises a display interface, such as a touch screen display. In alternate embodiments, the user interface32can include buttons or switches for manipulating and programming the settings of the system100, including for example the setpoint temperature. In one embodiment, the user interface32comprises or is part of a control panel for the hot water heater10. The user interface32can also be located remotely from the hot water heater10, and can be accessible through a computing device or a web based interface.

As is illustrated inFIG. 1, in one embodiment, the system100includes one or more temperature sensors24for detecting and monitoring the temperature of the water in the different portions of the system100. In the example ofFIG. 1, sensors24, such as thermistors, are shown on or thermally coupled to one or more of the inlet line16, the outlet line18, the mixed output line22and the hot water tank12. The sensor(s)24are generally configured to provide one or more signals or commands to the controller30that will allow the controller30to detect and determine temperature values for the water in various portions of the hot water system100.

In one embodiment, the sensors24are coupled to the controller30via a wired or wireless communication connection or interface. For purposes of the description herein, wireless communication connections and interfaces can include, but are not limited to, wireless radio, WiFi, Bluetooth, Zigbee and ethernet wireless type devices and interfaces.

Further, in some embodiments, the system100includes one or more flow detectors25. A flow detector25, which may for example be a flow meter or flow valve, may be provided for detecting flow rates of water therethrough in different portions of the system100. In the example ofFIG. 1, a flow detector25is shown in the outlet line18for detecting flow, and a flow rate, therethrough. Additionally or alternatively, a flow detector25may be provided in the mixed output line22and/or at other suitable locations in the system100. The flow detector(s)25are generally configured to provide one or more signals or commands to the controller30that will allow the controller30to detect and determine flow rates for the water in various portions of the hot water system100.

In one embodiment, the flow detectors25are coupled to the controller30via a wired or wireless communication connection or interface. For purposes of the description herein, wireless communication connections and interfaces can include, but are not limited to, wireless radio, WiFi, Bluetooth, Zigbee and ethernet wireless type devices and interfaces.

Referring now toFIG. 2, various embodiments of methods for monitoring electronic mixing valves20for hot water heater systems100are provided. In general, such methods provide improved operation of controllers30, electronic mixing valves20, and systems100in general. For example, such methods may advantageously detect electronic mixing valve20failures and allow for actions to be taken to alleviate such failures. For example, the electronic mixing valve may be adjusted to prevent excessively hot or cold water from being provided to a user, and the user may be notified of the failure. Advantageously, such methods may be performed without the use of thermal cutoffs.

It should be noted that controllers30as disclosed herein are capable of and may be configured to perform any methods and associated method steps as disclosed herein.

For example, a method200may include the step210of determining whether an output flow event212is occurring. An output flow event is the active flow of water from the hot water heater10generally to the plumbing40and thus to a user, and thus can include the flow of water through inlet line16(to mixing valve20), outlet line18, electronic mixing valve20, and/or mixed output line22. The existence of an output flow event can be determined, for example, by determining whether a flow rate from the tank12, through the outlet line18, through electronic mixing valve20, and/or through the mixed output line22is greater than zero or above a predetermined flow rate threshold. In some embodiments, a flow detector25may be utilized to determine such flow rate, and may transmit signals to the controller30to determine the flow rate and if an output flow event212is occurring. Alternatively, changes in temperature (as measured for example by a temperature sensor24) or other suitable apparatus and/or techniques may be utilized (in exemplary embodiments in conjunction with controller30) to determine a flow rate of water from the hot water heater10and thus to determine whether an output flow event is occurring.

Method200may further include, for example, the step220of determining a first temperature value222for water in the mixed output line22. Such step220may, for example, occur when an output flow event212is occurring and due to such output flow event212occurring. For example, as discussed, a temperature sensor24may be operatively coupled to the mixed output line22and the controller30. Temperature sensor24may transmit signals to the controller30to determine the temperature of the water in the mixed output line22. Accordingly, the first temperature value222may be determined based on signals received from the temperature sensor24. Alternatively, any suitable methods or apparatus may be utilized to determine the first temperature value212.

In some embodiments, the determining step220may be performed immediately upon the determination that an output flow event212is occurring. In other embodiments, the determining step220may occur after a predetermined delay time period, which may for example be initiated upon determination (via step210) that an output flow event212is occurring. The predetermined delay time period may, for example, be between 10 seconds and 45 seconds, such as between 15 seconds and 40 seconds, such as between 20 seconds and 30 seconds. This may allow the flow rate to stabilize before other method steps, as discussed herein, are performed.

Further, in some embodiments, the predetermined delay time period may reset when a change in a flow rate for the output flow event212is outside of a predetermined change range. For example, the predetermined change range may include a range of acceptable changes in flow rate (over time; i.e. flow rate slopes), and may in particular include a predetermined maximum change in flow rate. If a change in flow rate (as for example calculated by the controller30for the flow rate over a period of time, such as during the predetermined delay time period) is greater than the predetermined maximum change in flow rate, the predetermined delay time period may reset. This may further ensure that the flow rate is stable before other method steps, as discussed herein, are performed.

Method200may further include, for example, the step230of comparing the first temperature value222to a setpoint temperature value232to determine a first temperature error value234. Such step230may, for example, occur when an output flow event212is occurring and due to such output flow event212occurring. In some embodiments, step230may further occur after the predetermined delay time period has expired. The setpoint temperature value232may be the value selected by a user for desired water output temperature within the mixed output line22. For example, a user may select the setpoint temperature value232through use of the user interface32. In general, when the electronic mixing valve20is operational and not failing, when a setpoint temperature value232is selected, the controller30and electronic mixing valve20may react to adjust the electronic mixing valve20such that the actual temperature of water within the mixed output line22is within a particular tolerance level of the setpoint temperature value232.

In exemplary embodiments, comparing the first temperature value222to the setpoint temperature value232to determine the first temperature error value234includes subtracting the first temperature value222from the setpoint temperature value232. The resulting first temperature error value234is thus in these embodiments the difference between the first temperature value222and the setpoint temperature value232.

In some embodiments, a single comparison of the first temperature value222and setpoint temperature value232may be performed. In other embodiments, multiple comparisons over a period of time may be performed. For example, in some embodiments, the first temperature value222may be compared to the setpoint temperature value232for a predetermined time period (i.e. multiple times at a predetermined interval during the predetermined time period). The predetermined time period may, for example, be between 10 seconds and 45 seconds, such as between 15 seconds and 40 seconds, such as between 20 seconds and 30 seconds.

Method200may further include, for example, the step240of generating a failure signal242when the first temperature error value234is outside of a predetermined error range. Such step240may, for example, occur when an output flow event212is occurring and due to such output flow event212occurring. In exemplary embodiments, the predetermined error range may for example be between −2 degrees and 2 degrees, such as between −1 degree and 1 degree, such as between −0.75 degrees and 0.75 degrees, such as between −0.5 degrees and 0.5 degrees.

Notably, in embodiments wherein the first temperature value222is compared to the setpoint temperature value232in step230for a predetermined time period, the failure signal242may be generated when the first temperature error value234is outside of the predetermined error range at any time during the predetermined time period. In other words, if at any one interval during the predetermined time period when the first temperature value222is compared to the setpoint temperature value232the resulting first temperature error value234is outside of a predetermined error range, a failure signal242may be generated.

Notably, when a failure signal242is generated, further comparisons for the remainder of the predetermined time period may in some embodiments be ceased. Alternatively, such comparisons may continue for the remainder of the predetermined time period.

In some embodiments, method200may further include the step235of adding a failure count237to a failure count total239when the first temperature error value234is outside of a predetermined error range. For example, the failure count total239may be a counter programmed into the controller30, and a failure count237may be added to the failure count total239when the first temperature error value234is outside of a predetermined error range. In these embodiments, after the failure count237is added, various steps such as steps210,220and/or230may be repeated if the failure count total239does not meet or exceed a failure count threshold. The failure count threshold may, for example, be one, two, three, four, five or more failure counts237. When the failure count total239meets or exceeds the failure count threshold, the failure signal242may be generated as discussed.

In some embodiments, a method200in accordance with the present disclosure may further include secondary steps for determining whether the electronic mixing valve20has failed. Such steps may be utilized, for example, in cases wherein water in the tank12is at a temperature that is less than or equal to the setpoint temperature value232. For example, method200may include the step250of determining a second temperature value252for water in the tank12. Such step250may, for example, occur when an output flow event212is occurring and due to such output flow event212occurring. For example, as discussed, a temperature sensor24may be operatively coupled to the tank12and the controller30. Temperature sensor24may transmit signals to the controller30to determine the temperature of the water in the tank12. Accordingly, the second temperature value252may be determined based on signals received from the temperature sensor24. Alternatively, any suitable methods or apparatus may be utilized to determine the second temperature value252.

In some embodiments, the determining step250may be performed immediately upon the determination that an output flow event212is occurring. In other embodiments, the determining step250may occur after the predetermined delay time period as discussed above. Further, in some embodiments, the predetermined delay time period may reset when a change in a flow rate for the output flow event212is outside of a predetermined change range, as discussed above.

Method200may further include, for example, the step260of comparing the second temperature value252to the setpoint temperature value232to determine a second temperature error value264. Such step260may, for example, occur when an output flow event212is occurring and due to such output flow event212occurring. In some embodiments, step260may further occur after the predetermined delay time period has expired.

In exemplary embodiments, comparing the second temperature value252to the setpoint temperature value232to determine the second temperature error value264includes subtracting the second temperature value252from the setpoint temperature value232. The resulting second temperature error value264is thus in these embodiments the difference between the second temperature value252and the setpoint temperature value232.

In some embodiments, a single comparison of the second temperature value252and setpoint temperature value232may be performed. In other embodiments, multiple comparisons over a period of time may be performed. For example, in some embodiments, the second temperature value252may be compared to the setpoint temperature value232for a predetermined time period (i.e. multiple times at a predetermined interval during the predetermined time period). The predetermined time period may, for example, be between 10 seconds and 45 seconds, such as between 15 seconds and 40 seconds, such as between 20 seconds and 30 seconds.

In these embodiments, the failure signal242may be generated when, additionally or alternatively to the requirements as discussed above, the second temperature error value264is outside of a second predetermined error range. In exemplary embodiments, the predetermined error range may for example be between −2 degrees and 2 degrees, such as between −1 degree and 1 degree, such as between −0.75 degrees and 0.75 degrees, such as between −0.5 degrees and 0.5 degrees. Notably, such generation may only occur in these embodiments when the second temperature value252is less than or equal to the setpoint temperature value232.

Notably, in embodiments wherein the second temperature value252is compared to the setpoint temperature value232in step260for a predetermined time period, the failure signal242may be generated when the second temperature error value264is outside of the predetermined error range at any time during the predetermined time period. In other words, if at any one interval during the predetermined time period when the second temperature value252is compared to the setpoint temperature value232the resulting second temperature error value264is outside of a predetermined error range, a failure signal242may be generated.

When the failure signal242is generated, various steps may occur to alert a user to the potential failure of the electronic mixing valve20and/or to at least temporarily alleviate issues that may be caused by such failure. For example, in some embodiments, method200may further include, for example, the step270of transmitting failure signal242to the user interface32. When the user interface32receives the failure signal242, an alert, such as a visual (light, text, etc.) or auditory (bell, tone, etc) alert may be generated in the user interface32to alert a user to the potential failure of the electronic mixing valve20. Additionally or alternatively, in some embodiments, method200may further include, for example, the step280of adjusting the electronic mixing valve20when the failure signal242is generated. For example, the electronic mixing valve20may be adjusted to a more open position if there is an indication that the valve20failed closed, or may be adjusted to a more closed position if there is an indication that the valve20failed open.

Notably, in exemplary embodiment predetermined periods, ranges, values etc. as discussed herein may be programmed into the controller30. Such variables may be user adjustable (i.e. by a user via user interface32) and/or may initially be factory settings for the water heater10and system100.