US20210048225A1

US20210048225A1 - Gas valve operator drive circuit

Info

Publication number: US20210048225A1
Application number: US16/993,140
Authority: US
Inventors: Frederick Hazzard; Adam Myre; Gregory Young
Original assignee: Ademco Inc
Current assignee: Ademco Inc
Priority date: 2019-08-14
Filing date: 2020-08-13
Publication date: 2021-02-18

Abstract

A water heater comprising a thermoelectric device to power components of the water heater, a valve configured to control gas flow, and a controller. The controller may be configured to periodically determine one or more electrical parameters for holding the valve in the open state. The controller may be configured to alter the one or more parameters with the valve in an open state until the valve deviates from the open state. The controller may cause a current to flow through the valve based on the determined one or more electrical parameters.

Description

This application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/886,746 (filed Aug. 14, 2019), which is entitled, “GAS VALVE OPERATOR DRIVE CIRCUIT” and incorporated by reference herein in its entirety.

TECHNICAL FIELD

The disclosure relates to water heating systems.

BACKGROUND

Tank-type water heating systems which incorporate gas combustion as a heat source typically utilize a pilot flame issuing from a pilot burner to initiate combustion of a main gas flow. Combustion of the main gas flow initiates a flame at a main burner. The main burner flame typically heats a volume of water. A temperature sensing device in thermal communication with the volume of water may provide a temperature to a control system to serve as an indication of when pilot flame and main burner flame may be desired. The control system may initiate operations within the water heater system to initiate the pilot flame and the main burner flame by, for example, energizing valve actuators in order to establish the necessary gas flows to one or more dormant burners.

SUMMARY

The water heater system disclosed herein provides for the periodic determination of one or more electrical parameters required to maintain a one or more valves in an open position. The periodic determination of the one or more electrical parameters allows the control system to judiciously supply power in an efficient manner, such that energy significantly beyond what may be required for a specific valve operation is not expended. This may be beneficial when the water heater control system relies on a stored energy system or a thermoelectric device to supply operating power, rather than power from a line source external to the water heater.
The water heater system comprises at least a thermoelectric device, a valve, and a controller. The thermoelectric device may convert thermal energy into electrical energy and power one or more components of the water heater. The valve is configured to control whether there is a gas flow to cause a flame. The gas flow may be a main gas flow and the flame may be a main burner flame caused by thermal communication between a pilot flame and the main gas flow. In some examples, the gas flow may be the pilot gas flow and the flame may be the pilot flame. In some examples, the thermoelectric device converts thermal energy from the pilot flame into electrical energy.
The controller may be configured to receive power from the electrical energy generated by the thermoelectric device. The controller may be configured to receive power from a from a power source such as a battery or capacitor. The power source may be a non-rechargeable battery or pre-charged capacitor having a life that lasts as long as a life of the water heater device. The controller may periodically determine one or more electrical parameters for holding the valve in an open state. The one or more electrical parameters may be a voltage amplitude provided to the valve (e.g., to a solenoid or other electrical component comprising the valve), a current amplitude provided to the valve, or a voltage amplitude and a current amplitude provided to the valve. The controller may periodically determine the one or more electrical parameters based at least in part on information indicative of whether the valve is in the open state. The controller may cause a current to flow through the valve (e.g., through a valve actuator) based on the determine one or more electrical parameters. In an example, the valve is a solenoid valve actuated by a solenoid, and the controller causes a current to flow through the solenoid in accordance with the determined one or more electrical parameters.
The controller may be configured to determine an amount of energy generated by the thermoelectric device, and the information indicative of whether the valve is in the open state may be an amount of energy generated by the thermoelectric device. The indicative information may be an increase or a decrease in the electrical energy generated by the thermoelectric device. In some examples, when the valve controls whether there is a pilot gas flow causing a pilot flame, a decrease in the electrical energy generated may indicate the valve is no longer in the open state (e.g., the valve has deviated from the open state). In some examples, when the valve controls whether there is a main gas flow causing a main burner flame, an increase in the electrical energy generated may indicate the valve is no longer in the open state.
The controller may be configured to determine one or more of a voltage supplied to the valve, an inductive signature associated with the valve, or a current supplied to the valve. The information indicative of whether the valve is in the open state (or has deviated from the open state) may be at least one of the voltage supplied to the valve, the inductive signature of the valve, or the current supplied to the valve.
In examples, the valve is configured to hold in an open state while receiving a holding amount of the one or more electrical parameters. The holding amount may be a voltage amplitude provided to the valve, a current amplitude provided to the valve, or a voltage amplitude and a current amplitude provided to the valve. The holding amount may be a voltage amplitude, a current amplitude, or a voltage amplitude and a current amplitude provided to the valve which results in a holding current flowing to the valve. The controller may be configured to provide the holding amount to the valve and hold the valve in the open state. With the valve in the open state, the controller may determine a dropping amount by altering one or more of the electrical parameters until the valve deviates from the open state. The holding amount may be a voltage amplitude, a current amplitude, or a voltage amplitude and a current amplitude provided to the valve which results in a dropping current flowing to the valve. The controller may revise the holding amount of the one or more electrical parameters for the valve based on the dropping amount, and thereby periodically determine the one or more electrical parameters for holding the valve in the open state.
In this manner, the controller may recognize when the electrical power required to hold a specific valve open has decreased due to, for example, mechanical wear, changes in environmental conditions, or some other reason. This can provide advantage in scenarios where power availability may be limited. The system may be configured to subsequently utilize the determined electrical parameters for the specific valve going forward, so that the energy savings associated with a reduced hold current can be realized.
The water heater system may further comprise a temperature sensor. The controller may be configured to receive a reference temperature signal from the temperature sensor when the controller periodically determines and revises the holding amount of the one or more electrical parameters necessary to hold open the valve. The controller may associate the determined one or more electrical parameters with the reference temperature signal. Going forward, when operation of the valve is required, the controller may receive an environmental temperature signal indicative of a present environmental temperature, and cause current to flow through the valve based at least in part on the environmental temperature signal.
In examples, the valve is a main valve controlling whether there is a main gas flow. The main gas flow may be in thermal communication with a pilot flame to generate a main burner flame. The water heater may be an intermittent pilot system further comprising an pilot valve controlling whether there is a pilot gas flow to generate the pilot flame. The controller may be configured to periodically determine a holding amount of the one or more electrical parameters for each of the main valve and the pilot valve.
The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram of a pilot light and appliance burner integration in a water heater system.

FIG. 2A is an example pilot valve and main valve apparatus with a pilot servo valve and main servo valve in a closed position.

FIG. 2B is the example pilot valve and main valve apparatus with the pilot servo valve in an open position and the main servo valve in a closed position.

FIG. 2C is an example pilot valve and main valve apparatus with the pilot servo valve and the main servo valve in the open position.

FIG. 3 is an example of a control system for an intermittent pilot water heater.

FIG. 4 is an example of a control system configured to periodically determine one or more electrical parameters of a valve.

FIG. 5 is an example technique for determining one or more parameters required to hold a valve in an open state using a controller.

DETAILED DESCRIPTION

The water heater control system disclosed herein provides a controller configured to periodically determine one or more electrical parameters required to hold a valve in an open position, and then subsequently apply the determined one or more electrical parameters when operation of the valve is required. This periodic determination provides a capability for the control system to recognize when the power requirements for holding open a specific valve may have increased or decreased. This allows the controller to judiciously supply power in an efficient manner, such that energy significantly beyond what may be required for a specific valve operation is not expended. This may be beneficial when the water heater control system relies on a stored energy system or a thermoelectric device to supply operating power, rather than power from a line source external to the water heater.
A control system may benefit from a controller being configured to periodically determine one or more electrical parameters required to maintain one or more control valves in an open position, and then subsequently apply the one or more electrical parameters when control valve operation is required. The electrical power sufficient to maintain a given control valve open may decrease over the life and continued operation of the control valve due to mechanical wear, changes in environmental conditions, or other reasons. In a system which may rely whole or in part on a limited power supply, periodic evaluation and subsequent application of the sufficient power level for opening and holding open a specific control valve can mitigate excessive expenditures of the limited power available. Additionally, periodically determining and subsequently providing the sufficient levels of power may increase the availability of electrical power for other powered components either within the control system or elsewhere in a water heating system, as opposed to uniformly applying predetermined power levels throughout the life of a control valve.
The one or more valves may be control valves within a water heating system. For example, a first control valve such as a pilot servo valve may be configured to cause a pilot gas flow to issue from a pilot burner, while a second control valve such as a main servo valve may be configured to cause a main gas flow to issue from a main burner. Each valve may be operated via electrical power provided to a specific valve operator. For example, a control valve may be a solenoid operated valve comprising a solenoid, and the solenoid may be the specific valve operator.
The water heater control system provides for periodic determination of one or more electrical parameters required to maintain a control valve in an open position. Generally, the control valves are configured such that remaining in an open position is necessary to execute desired operations of the water heater. For example, the water heater may be an intermittent pilot system where a pilot servo valve is required to open and remain open in order to provide a pilot gas flow to a pilot burner, so that a pilot flame may be generated and sustained through the duration of some desired operating period. Similarly, a main servo valve may be required to open and remain open in order to provide a main gas flow to a main gas burner, so that a main burner flame may be generated and sustained until completion of the desired operating period. Closure of the pilot servo valve or the main servo valve before elapse of the desired operating period may result in premature termination of the main burner flame. Consequently, electrical power must be supplied to both the pilot servo valve and the main servo valve throughout the desired operating period.
In many control systems responsible for control valve operation, the necessary electrical parameters such as a current and/or voltage required to establish a control valve in an open position is initially determined either through testing or a manufacturer specification, then applied uniformly throughout the life of the control valve. However, in some cases, the electrical power required to maintain a given control valve open may decrease over the life and continued operation of the control valve, due to mechanical wear, changes in environmental conditions, or other reasons. For example, in some solenoid operated control valves, the holding currents necessary to maintain an open position might decrease by 3-25 times over the operating life of the control valve. When such changes occur, continuing to apply current and/or voltage to the control valve based on parameters initially determined at beginning of life can result in providing more power than is necessary. This can be a distinct disadvantage in scenarios where power availability may be limited. The system disclosed herein comprises a controller configured to periodically evaluate one or more of the electrical parameters provided to a specific control valve, allowing the controller to recognize when these required holding currents have decreased. The system is configured to determine the one or more electrical parameters required for operation of the control valve, and subsequently utilize the determined electrical parameters for the specific valve going forward, so that the energy savings associated with a reduced hold current can be realized.
This capability may be important in water heater systems that operate in the absence of a line voltage provided by an existing energy infrastructure, such as a line voltage provided to a residence or some other structure served. These water heater systems may be wholly or partially reliant on a thermoelectric device in order to generate necessary electrical power for operation. In conjunction with the thermoelectric device, the systems may also include an energy storage system to store some portion of the electrical energy generated by the thermoelectric device. The energy storage system may be relied upon for operations necessary when the thermoelectric device is dormant or not generating significant electrical power. The energy storage system may comprise a battery and/or capacitor. The energy storage system may comprise a non-rechargeable battery or pre-charged capacitor having a life intended to last as long as a life of the water heater device. The battery or capacitor may be replaceable.
As an example, in a control system for an intermittent pilot water heater, a stored energy system may provide the electrical energy for operations necessary to establish a pilot flame when pilot flame operation is called for, due to a call for heat using a main burner or for some other reason. These operations may include opening and holding open a pilot control valve configured to establish a pilot gas flow, and energizing an ignition circuit in thermal communication with the pilot gas flow to establish a pilot flame, among other possible duties. A controller configured to periodically evaluate one or more of the electrical parameters provided to the pilot control valve, update the one or more electrical parameters required, and subsequently utilize the updated electrical parameters in future operations may allow the system to recognize when the required energy for establishing the pilot flame have decreased, and to take advantage of the reduced power requirements which may be available. This may increase the energy budget available for other components which may be reliant on the stored energy system, as well as reduce the frequency of charging cycles which may be required due to a discharges from the stored energy system.
Once the pilot flame is established, a thermoelectric device in thermal communication with the pilot flame may be utilized to generate the electrical power necessary for additional operations required to generate a main burner flame. These operations may include opening and holding open a main control valve configured to establish a main gas flow to a main burner, with the main gas flow in thermal communication with the pilot flame to establish a main flame. A controller configured to periodically evaluate one or more of the electrical parameters provided to the main control valve, update the one or more electrical parameters required, and subsequently utilize the updated electrical parameters in future operations may allow the system to recognize when the required energy for establishing the main flame have decreased, and to take advantage of the reduced power requirements. This may increase the energy budget available for other components which may be reliant on the thermoelectric device.
FIG. 1 provides an example water heating system which might benefit from periodic determination of control valve electrical power requirements. FIG. 1 comprises pilot burner 41 and main burner 42 integrated in a water heater system 70. Fuel line 46 is in fluid communication with a main valve 44, which controls fuel flow to a main burner 42. A flue 50 may be an exhaust for main burner 42 in system 70. A pilot valve (not shown) may control fuel flow to a pilot burner 41 through fuel line 58. The pilot valve may be substantially in series, or in some other arrangement with main valve 44, and fuel to pilot burner 41 may come from fuel line 46 or some other source. There may be a pilot spark ignitor 56, for igniting a pilot gas flow discharging from pilot burner 54.
There may be a thermoelectric device 66 such as a thermopile connected by an electrical line 52 to control system 71. In examples, control system 71 may be at least partially enclosed within control housing 72. There may be a pilot spark ignitor 56 for igniting a pilot gas flow discharging from pilot burner 41. Pilot spark ignitor 56 may be connected via electrical line 60 to control system 71. Thermoelectric device 66 may be in thermal communication with pilot flame generated at pilot burner 41, and may convert some portion of a heat flux emitted by the pilot flame into electrical energy. A temperature sensing device 62 may be connected to control system 71 and situated in a water tank 64, or otherwise be configured to be in thermal communication with a volume of water in water tank 64. Control system 71 may incorporate a microcontroller configured to establish electrical or data communication with one or more of main valve 44, the pilot valve, and other components.
A control system may include a pilot valve operator configured to actuate the pilot valve of system 70, and may include a main valve operator configured to actuate main valve 44. The control system may also establish an electrical connection between thermoelectric device 66 and the main valve operator, such that the main valve operator can be powered by thermoelectric device 66. The control system may also include an energy storage system in electrical connection with the pilot valve operator.
In an intermittent pilot light system, when main burner 48 operation is called for, an operating sequence in system 70 might initially actuate the pilot valve and establish a pilot flame at pilot burner 41 prior to commencing main valve 44 operations. For example, control system 71 might initially actuate the pilot valve and pilot spark ignitor 56 using an energy storage system in order to establish the pilot flame at pilot burner 41. Subsequently, once the pilot flame is established, the operating sequence might actuate main valve 44 using power delivered by thermoelectric device 66. This operating sequence might be utilized to ensure the pilot flame is established prior to initiating main fuel flow to the burner.
In order to maintain the pilot flame, pilot valve 41 may be required to be held open by a valve operator consuming electrical power. For example, a position of pilot valve 41 may be controlled by an electrically actuated servo valve. Allowing the servo valve to close may close pilot valve 41, terminating a pilot gas flow to the pilot burner and extinguishing the pilot flame. Consequently, when the servo valve is an electrically actuated valve requiring energization to remain open, such as a solenoid valve, the servo valve receives electrical power throughout the period a pilot flame is desired. As a result, periodically determining a sufficient level of power necessary to open and hold open the servo valve avoids excessive expenditures of electrical power. Similarly, in order to maintain the main burner flame, main valve 44 may be required to be held open by another valve operator consuming electrical power. For example, a position of main valve 44 may be controlled by a second electrically actuated servo valve. Allowing the second servo valve to close may close main valve 44, terminating a main gas flow to the main burner and extinguishing the main burner flame. Consequently, when the second servo valve is an electrically actuated valve requiring energization to remain open, such as a solenoid valve, the second servo valve receives electrical power throughout the period a main burner flame is desired. As a result, periodically determining a sufficient level of power necessary to open and hold open the second servo valve avoids excessive expenditures by a control system providing electrical power to maintain pilot valve 41 and main valve 44 in an open position.
As described in more detail, operation of the pilot valve and the main valve may be driven by respective pilot valve operators and main valve operators. Examples of pilot valve operators and main valve operators are servo valves (e.g., solenoids), also referred to as milli-volt (mV) operators. The example techniques may be applied to the pilot valve operators and the main valve operators or directly to the pilot valve and the main valve. Accordingly, the example techniques described in this disclosure are described with respect to valves, examples of which include the pilot valve operators, main valve operators, pilot valve, and main valve.
Furthermore, utilization of the technique on pilot valve operators and pilot valves may not be necessary in all examples. For instance, in some examples where water heater system 70 is not an intermittent pilot system (e.g., system 70 is a continuous pilot or standing pilot system), pilot burner 41 may be lit substantially continuously, and there may not be pilot valve operators or pilot valves as specifically discussed with reference to FIG. 1. However, a pilot valve operator or pilot valve may still be present in examples where water heater system 70 is not an intermittent pilot system. In examples where water heater system 70 is an intermittent pilot system, water heater system 70 includes a pilot valve operator or pilot valve.
The valves (e.g., pilot valve operators, main valve operators, pilot valve, and main valve) may operate in accordance with a pick current, hold current, and drop current. The pick current is an amount of current needed to move a valve from a closed state to an open state. The hold current is an amount of current needed to keep the valve in an open state once in the open state. The drop current is a current slightly less than the hold current at which the valve deviates from the open state to a non-open state (e.g., closed state). The non-open state may be a fully closed state where for example a valve disc rests on a valve seat, or may be some state in between the open state and the fully closed state. For example, a non-open state may indicate a state that might be characterized as only 20% open, or 90% shut, or some other descriptor indicating a valve having some status between the open state and a fully shut state.
As described in more detail, a control system may be configured to determine the amount of the electrical parameters (e.g., electrical parameter levels) needed to keep the valves in the open state. For instance, rather than delivering current at a level much higher than the needed hold current, which can waste power, the control system may determine the electrical parameters needed to deliver the current to keep the valves in the open state where the amplitude of the delivered current is approximately equal to the hold current (e.g., equal to the hold current or 10-20% greater than the hold current).
FIGS. 2A-2C illustrates an example pilot valve and main valve configuration. At FIG. 2A, diaphragm 124 is illustrated in a closed position isolating an inlet 122, an intermediate pressure chamber 130, and a pilot outlet 132. Inlet 122 may be in fluid communication with a fuel supply and pilot outlet 132 may be in fluid communication with a pilot burner. Diaphragm 124 in the position illustrated is isolating the fuel supply and the pilot burner, at least at location 158. Diaphragm 124 is acted on by spring member 126, and fluid pressures in inlet 122 and chamber 128 are substantially equal, so that diaphragm 124 is maintained in the closed position. Servo valve 134 is maintaining disc 136 in a position isolating conduit 138 and intermediate pressure chamber 130 (intermediate pressure chamber 130 comprises and extends across 130 a, 130 b, and 130 c), maintaining the fluid pressures in inlet 122 and chamber 128 substantially equal. Additionally, fluid pressures in inlet 122 and chamber 128 are greater than a pressure at intermediate pressure chamber 130 and pilot outlet 132.
Valve body 120 also has diaphragm 142, and servo valve 152 having disc 154. Diaphragm 142 is in a closed position isolating intermediate pressure chamber 130 (comprising 130 a, 130 b, and 130 c) and outlet 148 at least at position 160 (outlet 148 comprises and extends across 148 a, 148 b, and 148 c). Outlet 148 may be in fluid communication with a main burner. Diaphragm 142 is acted on by spring member 144, and diaphragm 124 is maintained in the closed position at least by spring member 144. The pressure of chamber 130 is equalized with outlet 148 through conduit 162.
A pilot valve operator may be configured to cause servo valve 134 to reposition disc 136. In an example, control system 71 may be configured to energize the pilot valve operator. For example, FIG. 2B illustrates valve body 120 with servo valve 134 having positioned disc 136 to allow fluid communication between chamber 128 and intermediate pressure chamber 130. This provides at least some venting of the pressure in chamber 128 through first supply orifice 140 and reduces the pressure of chamber 128. This allows the pressure of inlet 122 to position diaphragm 124 into the position shown, where fluid communication between inlet 122 and pilot outlet 132 may occur at least at location 158. This allows fluid communication between inlet 122 and pilot outlet 132, and may allow a fuel supply to proceed from inlet 122 to the pilot burner. Additionally, with 152 closed, the pressure of chamber 146 is substantially equalized with intermediate pressure chamber 130 through conduit 162, and diaphragm 142 remains in the closed position.
With servo valve 134 held open and fuel supplied to a pilot burner, such as pilot burner 41, an ignitor such as ignitor 56 may establish a pilot flame at pilot burner 41 (FIG. 1). Thermoelectric device 66 in thermal communication with the pilot flame may convert some portion of the heat flux emitted by the pilot flame into electrical energy.
Allowing servo valve 134 to close will return diaphragm 124 to the position depicted in FIG. 2A, terminating the fuel supply to the pilot burner. Consequently, when servo valve 134 is an electrically actuated valve requiring energization to remain open, such as a solenoid valve, servo valve 134 receives electrical power throughout the period a pilot flame is desired. As a result, periodically determining a sufficient level of power necessary to open and hold open servo valve 134, and then applying that level of power to servo valve 134 when a pilot flame is called for, avoids excessive expenditures from a control system when providing power to servo valve 134. This may be particularly meaningful when an operating sequence calls for electrical power from an energy storage system to open and hold open servo valve 134 until a pilot flame generates and a thermoelectric electric device can commence generation of electrical power, or when a control system is wholly or partially reliant on a limited power supply to supply all or a large portion of the electric power needs required
A main valve operator may be configured to cause servo valve 152 to reposition disc 154. In an example, control system 71 may be configured to energize the main valve operator. For example, FIG. 2C illustrates valve body 120 with servo valve 152 having positioned disc 154 to allow fluid communication between chamber 146 and outlet 148 though conduit 150. This allows at least some venting of the pressure in chamber 146 through second supply orifice 157 and reduces the pressure of chamber 146. The venting of chamber 146 through conduit 150 allows the pressure of intermediate pressure chamber 130 to position diaphragm 142 into the position shown, where fluid communication between intermediate pressure chamber 130 and outlet 148 (comprising 148 a, 148 b, and 148 c) may occur at least at location 160. With servo valve 134 and servo valve 152 both positioned as shown at FIG. 2C, this allows fluid communication between inlet 122 and outlet 148, and may allow a fuel supply to proceed from inlet 122 to a main burner, such as main burner 42 (FIG. 1). With fuel supplied to the main burner and the pilot flame established, a main flame may be generated at the main burner.
Allowing servo valve 152 to close will return diaphragm 142 to the position depicted in FIGS. 2A-2B, terminating the main fuel supply to the main burner. Consequently, when servo valve 152 is an electrically actuated valve requiring energization to remain open, such as a solenoid valve, servo valve 152 receives electrical power throughout the period main burner operation is desired. As a result, excessive power expenditures can be avoided by periodically determining a sufficient level of power necessary to open and hold open servo valve 152 and then applying that level of power when main burner operation is called for. This may be particularly meaningful when a control system is wholly or partially reliant on a limited power supply to supply all or a large portion of the electric power needs required, including continued energization of servo valve 134 and servo valve 152 when main burner operation is called for. Providing an efficient amount of electric power to servo valves 134 and 152 may increase the availability of electrical power to other powered components in water heating system 70 (FIG. 2).
An example water heater control system 10 which may be configured to provide electrical power to one or more control valves is depicted at FIG. 3. Control system 10 may be configured operate a first control valve, such as servo valve 134 (FIG. 2A-2C), to cause a pilot gas flow to issue from a pilot burner. System 10 may also be configured to operate a second control valve, such as servo valve 152 (FIGS. 2A-2C), configured to cause a main gas flow to issue from a main burner. Each valve may be operated via electrical power provided to a specific valve operator. For example, each control valve may be a solenoid operated valve comprising a solenoid, and the solenoid may be the specific valve operator energized by system 10.
System 10 is an electric circuit configured to receive power from a thermoelectric device 16. Thermoelectric device 16 is a component configured to convert thermal energy into electrical power, such as a thermopile. In examples, thermoelectric device 16 may be the sole source of electrical energy to system 10 and the components within system 10, or system 10 may additionally comprise rechargeable or non-rechargeable batteries and/or capacitors. Thermoelectric device 66 of FIG. 1 is an example thermoelectric device 16. System 10 additionally comprises pilot valve operator 12 and main valve operator 14, as well as convertor 18. Pilot valve operator 12 may be configured to actuate a pilot valve such as the pilot valve of system 70 (FIG. 1), and main valve operator 14 may be configured to actuate a main valve such as main valve 44 (FIG. 1).
As illustrated, thermoelectric device 16 may provide power to main valve operator 14 through electrical line 34, and to convertor 18 through electrical connection 36. Convertor 18 may forward the generated power through electrical line 39 to energy storage system 20 through electrical connection 40, and to pilot valve operator 12 through electrical connection 38. Energy storage system 20 may also provide power to pilot valve operator 12 through electrical connection 40 and electrical connection 38. Energy storage system 20 thus provides the capability to store some portion of the electrical power generated by thermoelectric device 16, and also provides for powering of pilot valve operator 12 when thermoelectric device 16 is not generating. For example, thermoelectric device 16 may be configured to be in thermal communication with a heat source intended to operate intermittently, such as an intermittent pilot flame in a water heater. Energy storage system 20 may also power an ignition circuit 24. System 10 may further comprise a microcontroller 22 configured to receive power through electrical connection 37 from either convertor 18 or energy storage system 20. In the example illustrated at FIG. 3, Microcontroller 22 is shown as configured to receive power through electrical connection 37 from either convertor 18 or energy storage system 20. However, microcontroller 22 may be additionally or exclusively powered from a power source such as a battery or capacitor. The battery may be a non-rechargeable battery or pre-charged capacitor having a life that lasts as long as a life of the water heater device.
Additionally, system 10 may be configured to limit power flow from node 35 to energy storage system 20 to a single direction using, for example, converter 18 or another electronic device, so that while energy storage system 20 may receive power from thermoelectric device 16 through node 35, power flow cannot occur from energy storage system 20 to any components where node 35 is in the electrical path, such as main valve operator 14. This configuration may be employed so that main valve operator 14 can only receive power when thermoelectric device 16 is generating power, whereas pilot valve operator 12 may receive power from thermoelectric device 16 via converter 18 (when thermoelectric device 16 is generating) or energy storage system 20 (when thermoelectric device 16 is not generating). This configuration of system 10 may be provided to ensure a pilot flame is present at a pilot burner prior to establishing a main gas flow to a main burner.
System 10 may comprise microcontroller 22. In examples, microcontroller 22 is configured to establish and terminate electrical contact between thermoelectric device 16 and pilot valve operator 12 using, for example, a first electronic device 26. Microcontroller 22 may be is configured to establish and terminate electrical contact between thermoelectric device 16 and main valve operator 14 using, for example, a second electronic device 28. Microcontroller 22 may also be configured to establish and terminate electrical contact between convertor 18 and energy storage system 20 using, for example, a third electronic device 30. Microcontroller 22 may also be configured to establish and terminate electrical contact between pilot valve operator 12 and energy storage system 20 using second electronic device 26 and third electronic device 30. First electronic device 26, second electronic device 28, and third electronic device 30 may each be an apparatus sufficient to establish and terminate electrical contact between two portions of an electrical system in response to a signal from microcontroller 22. For example, first electronic device 26, second electronic device 28, and/or third electronic device 30 may comprise a field effect transistor (FET), a relay, a separate switching circuit, or any other device capable of establishing and terminating electrical contact in response to a signal from microcontroller 22.
System 10 may control an intermittent pilot water heating system or a water system in which the pilot is always lit and operate in the absence of an externally provided power supply. Under such conditions, when main burner operation is called for, pilot valve operator 12 may be de-energized and fuel flow through the pilot valve blocked, such that the pilot flame is dormant. With the pilot flame dormant, system 10 may initiate establishment of the dormant pilot flame by energizing pilot valve operator 12 using stored energy system 20, initiating a pilot gas flow to a pilot burner such as pilot burner 41 (FIG. 1). Similarly, system 10 may energize ignition circuit 24 to cause pilot spark ignitor 32 to generate thermal energy. Similar to pilot burner 41 and pilot spark ignitor 56 of FIG. 1, pilot spark ignitor 32 may be in thermal communication with the pilot gas flow such that the pilot flame generates. With thermoelectric device 16 in thermal communication with the established pilot flame, thermoelectric device 16 generates electrical energy from the thermal energy of the pilot flame and provides this electrical energy to main valve operator 14. Main valve operator 14 may actuate a main valve such as main valve 44 (FIG. 1), providing a main fuel flow to a main burner such as main burner 48 (FIG. 1). The established pilot flame is in thermal communication with the main fuel flow and generates combustion of the main fuel flow.
In between periods where a main burner flame is requested, microcontroller 22 of system 10 may be additionally configured to periodically wake and check the status of energy storage system 20. This ensures that energy storage system 20 has sufficient stored energy to initiate the pilot flame sequence described above when necessary. If energy storage system 20 is below a threshold level of charge, microcontroller 22 may be configured to energize pilot valve operator 12 using stored energy system 20, and/or may be configured to initiate the pilot gas flow, energize ignition circuit 24, and cause establishment of the pilot flame and generation of electrical energy from thermoelectric device 16. Microcontroller 22 may be configured to provide the electrical energy generated by thermoelectric device 16 to stored energy system 20, in order to recharge stored energy system 20.
A control system such as system 10 may benefit from microcontroller 22 being configured to periodically determine one or more electrical parameters required to maintain a control valve in an open position, and then subsequently apply the one or more electrical parameters when control valve operation is required. As discussed, the electrical power sufficient to maintain a given control valve open may increase and/or decrease over the life and continued operation of the control valve due to mechanical wear, changes in environmental conditions, or other reasons. In a system such as system 10—which relies on either a thermoelectric device generating electrical power, or an energy storage system providing electrical power previously generated by the thermoelectric device—periodic evaluation and subsequent application of the sufficient power level for opening and holding open a specific control valve can mitigate excessive expenditures of the limited power available. Additionally, periodically determining and subsequently providing the sufficient levels of power may increase the availability of electrical power for other powered components either within the control system or elsewhere in a water heating system, as opposed to uniformly applying predetermined power levels throughout the life of a control valve.
As an example, FIG. 4 illustrates a system 80 suitable for use within a water heating system such as water heating system 70 (FIG. 1). As will be discussed, system 80 may be incorporated within or present in a water heater control system such as system 10 (FIG. 3). System 80 comprises a microprocessor 82 configured to receive power from thermoelectric device 88. In FIG. 4, microprocessor 82 is configured to receive power from thermoelectric device 88 via electrical lead 81 and electrical connection 83. Thermoelectric device 88 is configured to generate electrical energy by converting thermal energy from a flame 92. Flame 92 is sustained by a gas flow 91 flowing into burner 93. Thermoelectric device 88 may be, for example, thermoelectric device 16 (FIG. 3) or thermoelectric device 66 (FIG. 1). Microprocessor 82 may be microprocessor 22 (FIG. 3). Gas flow 91 may be, for example, a pilot gas flow flowing into pilot burner 41.
System 80 further includes valve operator 84 within valve 87. Valve operator 84 is configured to establish a position of valve 87. Valve operator 84 might be, for example, pilot valve operator 12 or main valve operator 14 (FIG. 3). Valve 87 is configured to control whether or not a gas flow is present to cause a flame, based for example on a position of disc 90. Valve 87 might be, for example, servo valve 134 configured to control whether a pilot gas flow issues from pilot outlet 132, or servo valve 152 configured to control whether a main gas flow issues from outlet 156 (FIGS. 2A-2C).
Microcontroller 82 is configured to provide or facilitate some portion of a voltage present at node 94 to power valve operator 84. For example, microcontroller 84 may be configured to utilize electronic device 86 to provide some portion of the voltage at node 94 to valve operator 84. Electronic device 86 may be an apparatus sufficient to establish and terminate electrical contact between valve operator 84 and node 94, among other functions. For example, electronic device 86 may be a circuit comprising a Pulse Width Modulator (PWM) controlling a Field Effect Transistor (FET), and microcontroller 84 may be configured to determine the switching rate and/or pulse period of the PWM. The FET may be in series with valve operator 84 and node 94, and the PWM may be configured to cause the FET to rapidly open and close, to provide an average voltage and average current to valve operator 84 determined by, for example, a ratio of the FET on-time to a pulse period determined by the PWM.
Microcontroller 82 is configured to provide or facilitate one or more electrical parameters to valve operator 84 and cause sufficient current to flow through valve operator 84 to establish and hold valve 87 in an open state. For example, when valve 84 is a solenoid valve comprising a solenoid and a plunger and valve operator 84 is the solenoid, microcontroller 82 may provide one or more electrical parameters to valve operator 84 to initially generate a pick current to bring the plunger to an open state, followed by a generally lower hold current to maintain the plunger in the open state. Microcontroller 82 is further configured periodically determine one or more electrical parameters for holding valve 87 in the open state, based at least in part on information indicative of whether the valve is in the open state.
For example, when valve 87 is a solenoid valve comprising a solenoid and a plunger and valve operator 84 is the solenoid, microcontroller 82 may be configured to alter the one or more electrical parameters provided to valve operator 84 in a manner that causes a decrease in the current through the solenoid from a holding current to a drop current. Microcontroller 82 may then revise the one or more electrical parameters for holding valve 87 in the open state based on the quantity of the one or more parameters which resulted in the drop current.
In other words, microcontroller 82 may first open valve 87, and then keep reducing the current that flows through valve operator 84 (e.g., modify the duty cycle of the PWM to reduce the current that flows through valve operator 84). Microcontroller 82 may keep reducing the current until valve 87 closes (or deviates from the open state). The current at which valve 87 closes is the drop current. Microcontroller 82 may determine the electrical parameters that generated the current level right before the drop current level as microcontroller 82 was reducing the current flowing through valve operator 84. Microcontroller 82 may then cause the determined electrical parameters to be applied to valve 87 the next time valve 87 is to remain open (e.g., microcontroller 82 may first apply a pick current to cause valve 87 to transition to an open state and then apply the determined electrical parameters to keep valve 87 in the open state). Microcontroller 82 may periodically perform such operations to determine the minimum current needed to keep valve 87 in an open state (e.g., determine the hold current) and deliver current at or approximately at the hold current (e.g., up to 20% above the drop current).
As described above, part of the technique in which microcontroller 82 determines the hold current and the drop current is based on information indicative of whether valve 87 is in an open state or a closed state (e.g., if valve 87 has deviated from an open state). Microcontroller 82 may be configured to discern the indicative information evidencing that valve 87 has experienced the drop current and deviated from an open state (e.g., transitioned from an open position to a generally closed position) through a variety of methods, including a change in the amount of electrical energy received from thermoelectric device 88, or a voltage signature, current signature, or inductive signature of valve operator 84.
Having revised the one or more electrical parameters based on the quantity of the one or more parameters which resulted in the drop current, and having thereby determined one or more electrical parameters for holding valve 87 in the open state, microcontroller 82 is configured to cause a current to flow through valve operator 84 based on the determined one or more parameters. This capability allows microprocessor 84 to adjust the electrical power provided to hold open valve operator 84 as the electrical power requirements change over the operating lifetime of valve operator 84 within system 80. The periodic evaluation and subsequent application of the electrical power level for holding open valve 87 can mitigate excessive expenditures of the limited power which may be available to system 80.
A controller such as microcontroller 82 can offer significant advantage when utilized in a system such as system 10 (FIG. 3), where the periodic operation of power pilot operator 12, main valve operator 14, microcontroller 22, converter 18, ignition circuit 24, and pilot spark ignitor 32 may be wholly reliant on electrical power either directly generated by thermoelectric device 16, or generated by thermoelectric device 16 and stored by energy storage system 20. Reducing the electrical energy provided to pilot valve operator 12 to hold open, for example, pilot servo valve 134, and reducing the electrical energy provided to main valve operator 14 to hold open, for example, main servo valve 152, may decrease the overall electrical energy expenditure required to initiate and maintain pilot and main burner flames when required. This reduction may decrease the amount of stored energy withdrawn from energy storage system 20 during the period when pilot valve operator 12 is energized but thermoelectric device 16 is not yet generating electrical energy. This reduction may also decrease the portion of the electrical energy generated by thermoelectric device 16 which must be dedicated to energizing pilot valve operator 12 and main valve operator 14, thereby increasing the energy budget which might be allocated to other components present in the water heating system.
The one or more electrical parameters required to hold valve 87 in an open state may include a voltage provided to valve operator 84, with microprocessor 82 is configured to cause a current to flow through valve operator 84 based on the voltage. The one or more electrical parameters required to hold valve 87 in an open state may include a current provided to valve operator 84, with microprocessor 82 is configured to cause the current to flow through valve operator 84. Microprocessor 82 is configured to cause a current to flow through valve operator 84 based on the determined one or more electrical parameters. In examples, microprocessor 82 is configured to determine a holding amount of the one or more electrical parameters for holding valve 87 in an open position by establishing valve 87 in an open position, confirming valve 87 is in the open position, then altering the one or more electrical parameters provided and determining when valve 87 deviates from the open position.
Microcontroller 82 may determine when valve 87 is in an open state using any suitable technique. In an example, microcontroller 82 determines that valve 87 is in an open state based on reception of an increase in the amount of electrical energy generated by thermoelectric device 91. As discussed, valve 87 may be configured to control whether or not gas flow 91 sustaining flame 92 is present, and thermoelectric device 88 is configured to generate electrical energy by converting thermal energy from a flame 92. Consequently, microprocessor 82 may conclude that valve 87 is in an open position based on an increase in the electrical energy received from thermoelectric device 88. Microprocessor 82 may also conclude that valve 87 has closed or deviated from the open state based on a decrease in the electrical energy received from thermoelectric device 88. Correspondingly, microprocessor 82 may be configured to discern information indicative of whether valve 87 is in the open state based at least in part on the electrical energy received from thermoelectric device 88, and may be configured to determine that valve 87 has deviated from the open state (e.g. Closed) based at least in part on the electrical energy received from thermoelectric device 88.
The increase in the electrical energy is generally due to the pilot flame, which means that the pilot gas is allowed to flow, which means that valve 87 is open. Conversely, when valve 87 is closed, gas flow 91 is not present and the pilot light extinguishes, causing the voltage from thermoelectric device 88 to be substantially lowered (e.g., close to or equal to zero). Accordingly, as microcontroller 82 reduces the current to determine the minimum current needed to keep valve 87 open, once microcontroller 82 reduces the current to the drop current, valve 87 may close and thermopile 88 may stop generating a voltage. Microcontroller 82 may utilize this sudden drop in the voltage from thermopile 88 as indicative of gas flow 91 shutting off, indicating that valve 87 is substantially closed, and indicating that microcontroller 82 has reduced the current through valve 87 to the drop current of valve 87.
Additionally, and as will be discussed, in some examples microprocessor 82 may conclude that valve 87 is in an open position based on a decrease in the electrical energy received from thermoelectric device 88. For instance, in examples where valve 87 is for a main burner, the pilot valve is already open and a pilot flame may be lit. In such examples, gas flow 91 is for the main burner. When valve 87 is open, and gas flow 91 flows to light the main burner, there may be a much stronger flame, which can cause thermoelectric device 88 to generate a lower voltage due to an increase in an overall ambient temperature. Thermoelectric device 88 generates a voltage based on a differential temperature across two or more sensors. If the overall ambient temperature is high, due to a relatively strong flame from the main burner, then the differential temperature may be lower, and the voltage from thermoelectric device 88 may be lower. Accordingly, when valve 87 controls the gas flow for the main burner, a decrease in voltage from thermoelectric device 88 may be indicative of valve 87 being open. Conversely, when the main burner flame extinguishes, the voltage from thermoelectric device 88 may increase, indicating valve 87 has closed (or deviated from the open state). Therefore, by determining whether the voltage from thermoelectric device 88 increased or decreased, microcontroller 82 may determine whether a valve (e.g., valve 87) has deviated from the open state.
In some examples, microcontroller 82 might discern information indicative of whether valve 87 is in an open state based on a voltage supplied to valve operator 84. In some examples, microcontroller 82 might discern information indicative of whether valve 87 is in an open state based on a current supplied to valve operator 84. In some examples, microcontroller 82 might discern information indicative of whether valve 87 is in an open state based on an inductive signal of valve operator 84.
For example, when valve 87 is a solenoid valve comprising a plunger and valve operator 84 is a coil influencing a position of the plunger, the valve operator 84 would be expected to define a performance curve between a first state when an air gap between the coil and plunger is at a maximum (air gap open (AGO)) and a second state when the air gap between the coil and plunger is at a minimum (air gap closed(AGC)). The performance curve may have particular voltage, current, and/or inductive signature markers indicating when the AGO and AGC positions occur or are being approached. The marker may be, for example, a certain increase or decrease of the voltage, current, and/or inductive signature, or may be the attainment of a specific value of the voltage, current, and/or inductive signature. Microprocessor 82 may be configured to recognize one or more of these markers associated with the AGO and AGC positions, and determine when valve 87 is in an open state based on the marker recognized. Correspondingly, microprocessor 82 may be configured to discern information indicative of whether valve 87 is in the open state based at least in part on an observed increase or decrease of the voltage, current, and/or inductive signature, or recognition of an evident voltage, current, and/or inductive signature marker. Microprocessor 82 may also be configured to determine that valve 87 has deviated from the open state (e.g. Closed) based at least in part on a recognized increase or decrease of the voltage, current, and/or inductive signature, or recognition of a distinct voltage, current, and/or inductive signature marker.
In an example, microcontroller 82 periodically determines the one or more electrical parameters for holding valve 87 in the open state by initially causing valve 87 to assume and hold an open position. Microprocessor 82 may be configured to accomplish this by initially providing a picking amount of the one or more electrical parameters to cause a pick current to flow to valve operator 84 to open valve 87, followed by providing a holding amount of the one or more electrical parameters to cause a hold current to flow to valve operator 84 to hold open valve 87. The picking amount and the holding amount initially provided may be based on one or more of a previous evaluation of the electrical parameters necessary to open and maintain valve 87 in an open state, predetermined test levels of the picking amount and holding amount, and the picking and holding amounts the controller is presently configured to provide at the commencement of the periodic determination.
With valve 87 established in the open state, microcontroller 82 evaluates the holding amount by decreasing the one or more electrical parameters until valve 87 deviates from the open position. In an example, microcontroller 82 is configured to decrease the one or more electrical parameters utilizing electronic device 86. Electronic device 86 may be configured to decreases the one or more electrical parameters based on direction from microprocessor 82.
For example and as discussed, electronic device 86 may be a circuit comprising a PWM controlling a FET. The FET may be in series with valve operator 84 and node 94, and the PWM may be configured to cause the FET to rapidly open and close in order to provide an average voltage and average current to valve operator 84. Microcontroller 82 may be configured to control the duty cycle (e.g., pulse period) of the PWM, and may decreases the one or more electrical parameters by altering the switching rate and/or pulse period. Other techniques may be utilized. For example, microcontroller 82 may be configured to control a potentiometer using some portion of the voltage at node 94 as an input voltage and supplying an output voltage to valve operator 84. The potentiometer may be a digital potentiometer. Microcontroller 82 may be configured to control an electronic circuit comprising one or more of an op-amp, a transistor, and/or a diode, with the electronic circuit configured within system 80 to provide a voltage to valve operator 84. In some examples, microcontroller 82 may be configured to control an independent or dependent current source configured within system 80 to provide a current to the coil of valve operator 84. The current source may be an electronic circuit comprising an op-amp, a transistor, and/or a diode. Microcontroller 82 may be configured to control a rheostat configured within system 80 to provide a current to the coil of valve operator 84.
As used herein, “holding amount” means a voltage, a current, or a voltage and a current provided to a valve in order to maintain the valve in an open state. In an example, the voltage, current, or voltage and current is provided to a valve operator for the valve. The valve may be a solenoid valve comprising a solenoid as the valve operator, and the voltage, current, or voltage and current may cause a holding current to flow through the solenoid.
As used herein, “picking amount” means a voltage, a current, or a voltage and a current provided to an actuated valve (e.g., a valve in a de-actuated state) in order to transition the valve from a closed state to an open state. In an example, the voltage, current, or voltage and current is provided to a valve operator for the valve. The valve may be a solenoid valve comprising a solenoid as the valve operator, and the voltage, current, or voltage and current may cause a pick current to flow through the solenoid.
As used herein, “dropping amount” means a voltage, a current, or a voltage and a current provided to a valve which is insufficient to maintain the valve in an open state. The dropping amount may cause the valve to transition from an open state to a closed state. In an example, the voltage, current, or voltage and current is provided to a valve operator for the valve. The valve may be a solenoid valve comprising a solenoid as the valve operator, and the voltage, current, or voltage and current may cause a drop current to flow through the solenoid.
As used herein, a valve in an open state means a valve where a microprocessor such has microprocessor 82 has discerned that the valve is in the open state using one or more indications, such as an increase or decrease in electrical energy received from a thermoelectric device, an observed increase or decrease of the voltage, current, and/or inductive signature of the valve or a valve operator, and/or an evident voltage, current, and/or inductive signature marker of the valve or valve operator.
As used herein, a valve in a closed state or a valve which has deviated from an open state means a valve where a microprocessor such as microprocessor 82 has discerned that the valve is in the closed state or has deviated from the open state using one or more indications, such as an increase or decrease in electrical energy received from a thermoelectric device, a recognized increase or decrease of the voltage, current, and/or inductive signature of the valve or a valve operator, and/or recognition of a distinct voltage, current, and/or inductive signature marker of the valve or valve operator.
Microcontroller 82 may be configured to determine when valve 87 deviates from an open position using a variety of suitable techniques. For example, microcontroller 82 may be configured to determine when valve 87 deviates from an open position based on an increase or decrease in the electrical energy received from thermoelectric device 88. In examples, microcontroller 82 may be configured to determine when valve 87 deviates from an open position based on changes to the voltage, current, and/or inductive signature markers of valve operator 84. In this manner, microcontroller may determine a dropping amount of the one or more parameters, where the dropping amount is the amount provided to valve operator 84 when microcontroller 82 determines that valve 87 has deviated from an open position.
Microcontroller 82 may be configured to then revise the holding amount of the one or more electrical parameters provided to valve operator 84 based on the dropping amount of the one or more electrical parameters. For example, microcontroller 82 may revise the holding amount of the one or more electrical parameters by adding a margin to the dropping amount of the one or more electrical parameters. In this manner, microprocessor 84 may recognize when the electrical power required to maintain valve 87 in the open position has decreased due to mechanical wear, changes in environmental conditions, or some other reason, and subsequently apply the revised one or more electrical parameters. Periodic determination of the electrical parameters necessary to hold open specific control valves mitigates excess expenditures of electrical power, and can provide significant advantage in the operations of systems where available power may be limited. This can be particularly beneficial in water heater control systems which rely on a stored energy system or a thermoelectric device to supply operating power, rather than power from a line source external to the water heater. For example, the periodic determination of electrical parameters may be particularly beneficial in a system such as water heater system 70 (FIG. 1) controlled by control system 10 (FIG. 3), where energy storage system 20 may be expected to provide power for a variety of functions when thermoelectric device 16 (or thermoelectric device 41 of FIG. 2) is not providing appreciable electrical power.
In some examples, microcontroller 82 is configured to receive a temperature signal T_ENVindicative of the environmental temperature conditions of valve operator 84 and associate the determined parameters with the temperature signal T_ENV. For example, when valve operator 84 is located within control system 71, microcontroller 82 may be configured to receive a temperature signal T_ENVindicative of the environmental temperature conditions of control system 71 (e.g., a temperature within control housing 72). In some examples, control system 71 includes a temperature sensor configured to determine a temperature indicative of the environmental temperature (e.g., a temperature sensor within control housing 71) and provide the temperature signal T_ENVto microcontroller 82. In some examples, a water heating system comprises a temperature sensor such as temperature sensing device 62 (FIG. 1) configured to provide a signal T_REF, and the temperature signal T_ENVis based on a signal T_REFindicative of a temperature from the temperature sensor.
Microcontroller 82 may associate the determined parameters with the temperature signal T_ENVwhen periodically determining the one or more parameters. Over time, microcontroller 82 may determine a plurality of data sets, with each data set comprising a particular temperature signal T_ENVor other temperature signal and, for example, a holding amount of the one or more electrical parameters required to hold open valve 87 at the particular temperature signal T_ENV. Subsequently, when valve 87 operation is required, microcontroller 82 may receive the temperature signal T_ENVproviding a possible indication of the current temperature conditions of valve operator 84, and cause current to flow through valve operator 84 using the plurality of data sets and based on the temperature signal T_ENVin the plurality of data sets. This may be advantageous when valve operator 84 is potentially subject to a variety of environmental temperatures and the varying environmental temperatures impact the electrical properties of valve operator 84. For example, valve operator 84 may be subject to varying environmental temperatures as a result of changing seasons, or due to a proximity to other appliances or devices which generate heat on a periodic basis, or some other reason.
In examples, valve 87 of FIG. 4 is a valve configured to provide a pilot gas flow to cause a pilot flame. For example, valve 87 may be servo valve 134 (FIGS. 2A-2C) configured to control whether a pilot gas flow issues from pilot outlet 132 to pilot burner 41 of water heater system 70 (FIG. 1). Valve operator 84 (FIG. 4) may be a valve operator controlling servo valve 134, such as pilot valve operator 12 (FIG. 3). Electronic component 86 (FIG. 4) may be a component controlling a voltage and current provided to pilot valve operator 12, such as first electronic component 26 (FIG. 3). Microprocessor 82 may be microprocessor 22 of FIG. 3, configured to establish and terminate electrical contact between thermoelectric device 16 and pilot valve operator 12 using first electronic device 26, as well as to periodically determine the one or more electrical parameters sufficient to hold open servo valve 134 using pilot valve operator 12. Microcontroller 22 may be configured to control one or more electrical parameters provided to pilot valve operator 12 using first electronic device 26. For example, first electronic device 26 may be a circuit comprising a Pulse Width Modulator (PWM) controlling a Field Effect Transistor (FET), and microcontroller 22 may be configured to determine the switching rate and/or pulse period of the PWM to provide an average voltage and average current to pilot valve operator 12. Microcontroller 22 may be configured to determine a holding amount of the one or more parameters for pilot valve operator 12 and servo valve 134 in like manner to the technique employed by microprocessor 82 for valve operator 84 and valve 87.
In some examples, valve 87 of FIG. 4 is a valve configured to provide a main gas flow to cause a main burner flame. For example, valve 87 may be servo valve 152 (FIGS. 2A-2C) configured to control whether a main gas flow issues from outlet 156 to main burner 42 of water heater system 70 (FIG. 1). Valve operator 84 (FIG. 4) may be a valve operator controlling servo valve 152, such as main valve operator 14 (FIG. 3). Electronic component 86 (FIG. 4) may be a component controlling a voltage and current provided to main valve operator 14, such as second electronic component 28 (FIG. 3). Microprocessor 82 may be microprocessor 22 of FIG. 3 configured to establish and terminate electrical contact between thermoelectric device 16 and main valve operator 14 using second electronic device 28, as well as to periodically determine the one or more electrical parameters sufficient to hold open servo valve 152 using main valve operator 14. Microcontroller 22 may be configured to control one or more electrical parameters provided to main valve operator 14 using second electronic device 28. For example, second electronic device 28 may be a circuit comprising a Pulse Width Modulator (PWM) controlling a Field Effect Transistor (FET), and microcontroller 22 may be configured to determine the duty cycle (e.g., pulse period) of the PWM to provide an average voltage and average current to main valve operator 14. Microcontroller 22 may be configured to determine a holding amount of the one or more parameters for main valve operator 14 and servo valve 152 in like manner to the technique employed by microprocessor 82 for valve operator 84 and valve 87.
In some examples, the configuration between microcontroller 82 and valve operator 84 illustrated in FIG. 4 may be present between a microcontroller and more than one valve operator. For example, in FIG. 3, microcontroller 22 may be configured to establish and terminate electrical contact between thermoelectric device 16 and pilot valve operator 12 using first electronic device 26, and establish and terminate electrical contact between thermoelectric device 16 and main valve operator 14 using second electronic device 28. Further, first electronic device 26 may be configured to decrease one or more electrical parameters to pilot valve operator 12 based on direction from microprocessor 22, and second electronic device 28 may be configured to decrease one or more electrical parameters to main valve operator 14 based on direction from microprocessor 22. First electronic device 26 and second electronic device 28 may each be a circuit comprising a PWM controlling a FET, and microcontroller 22 may be configured to determine the switching rate and/or pulse period of the PWM of each circuit to provide a first average voltage and first average current to pilot valve operator 12, and a second average voltage and second average current to main valve operator 14. Microcontroller 22 may be configured to determine a holding amount of the one or more parameters for pilot valve operator 12 and servo valve 134 in like manner to the technique employed by microprocessor 82 for valve operator 84 and valve 87, as well as be configured to determine a holding amount of the one or more parameters for main valve operator 14 and servo valve 152 in like manner to the technique employed by microprocessor 82 for valve operator 84 and valve 87.
An example technique a controller may perform to periodically determine one or more electrical parameters for holding a valve might comprise providing a sufficient amount of the one or more electrical parameters for holding the valve in an open state. The sufficient amount may be based on a holding amount previously determined by the controller. The sufficient amount of the one or more electrical parameters may include a voltage and may include a current. The controller may cause a current to flow through valve operator based on one or more electrical parameters. The controller may receive a signal indicative of a temperature T_REF.
After providing the sufficient amount of the one or more electrical parameters, the controller may determine that the valve is open. The controller may determine the valve is open based on an amount of electrical energy generated by a thermoelectric device. The controller may determine when the valve is open based on a voltage supplied to a valve operator establishing a position of the valve. The controller may determine when the valve is open based on a current supplied to a valve operator. The controller may determine the valve is open based on an inductive signal of the valve operator.
With the valve in the open state, the controller may decrease the one or more electrical parameters. The controller may decrease a voltage and cause current to flow through the valve operator based on the reduced voltage. The controller may reduce a current and cause the reduced current to flow through the valve operator. The controller may determine whether the valve has deviated from the open state. The controller may determine whether the valve has deviated from the open state based on an increase or decrease in the amount of electrical energy received from the thermoelectric device. The controller may determine whether the valve has deviated from the open state based on changes to the voltage, current, and/or inductive signature markers of a valve operator establishing a position of the valve.
If the valve has not deviated from the open state, the controller may repeat decreasing the one or more electrical parameters and determining if the valve has deviated from the open state. If the valve has deviated from the open state, the controller may designate the one or more electrical parameters currently supplied to the valve operator as the dropping amount, and revise the holding amount of electrical power based on the dropping amount. For example, controller may revise the sufficient amount of the one or more electrical parameters by adding a predetermined margin to the dropping amount of the one or more electrical parameters which resulted in the deviation of the valve from the open state. The controller may associate the revised holding amount of the one or more electrical parameters with the signal indicative of a temperature T_REF.
A controller such as microcontroller 82 configured to periodically establish and revise the one or more electrical parameters required to maintain a specific control valve in an open position may provide distinct advantage when utilized in a system such as system 10 (FIG. 3), where power pilot operator 12, main valve operator 14, microcontroller 22, converter 18, ignition circuit 24, and pilot spark ignitor 32 may be wholly reliant on electrical power provided directly or indirectly by thermoelectric device 16. Reducing the required electrical energy which must be provided to pilot valve operator 12 and main valve operator 14 may decrease the overall electrical energy expenditure required to initiate and maintain pilot and main burner flames when required, and increase the energy budget which might be allocated to other components present in the water heating system.
In some examples, microcontroller 22 (FIG. 3) is configured in like manner to microcontroller 88, and may periodically determine the one or more electrical parameters sufficient to hold open servo valve 134 using pilot valve operator 12 (i.e., the holding amount for pilot valve operator 12). Microcontroller 22 may be configured to utilize first electronic component 26 to control a voltage and/or current provided to pilot valve operator 12. Microcontroller 22 may be configured to determine when servo valve 134 is open and when servo valve 134 deviates from an open position based on, for example, an amount of electrical energy generated by thermoelectric device 16 (or thermoelectric device 66 of FIG. 1), a voltage supplied to pilot valve operator 12, a current supplied to pilot valve operator 12, and/or an inductive signal of pilot valve operator 12. Microcontroller 22 may be configured to revise the holding amount of the one or more electrical parameters provided to pilot valve operator 12 based on the periodic determination. In examples, microcontroller 22 may be configured to associate the revised holding amount of the one or more electrical parameters with a temperature signal T_REFfrom a temperature sensor such as temperature sensor 62 (FIG. 1). In examples, microcontroller 22 provides a holding amount of the one or more electrical parameters to pilot valve operator 12 based on comparison of a temperature T_ENVreceived and a T_REFvalue.
Microcontroller 22 (FIG. 3) may be further configured to periodically determine the one or more electrical parameters sufficient to hold open servo valve 152 using main valve operator 14 (i.e., the holding amount for main valve operator 14). Microcontroller 22 may be configured to utilize second electronic component 28 to control a voltage and/or current provided to main valve operator 14. Microcontroller 22 may be configured to determine when servo valve 152 is open and when servo valve 152 deviates from an open position based on, for example, an amount of electrical energy generated by thermoelectric device 16 (or thermoelectric device 66 of FIG. 1), a voltage supplied to main valve operator 14, a current supplied to main valve operator 14, and/or an inductive signal of main valve operator 16. Microcontroller 22 may be configured to revise the holding amount of the one or more electrical parameters provided to main valve operator 14 based on the periodic determination. In examples, microcontroller 22 may be configured to associate the revised holding amount of the one or more electrical parameters with a temperature signal T_REFfrom a temperature sensor such as temperature sensor 62 (FIG. 1). In examples, microcontroller 22 provides a holding amount of the one or more electrical parameters to main valve operator 14 based on comparison of a temperature T_ENVreceived and a T_REFvalue.
In some examples, when microprocessor 22 is configured to periodically determine holding amounts of the one or more electrical parameters for both pilot valve operator 12 and main valve operator 14, microprocessor 22 may determine that a valve operated by pilot valve operator 12 is in an open state based on an increase in the electrical energy received from thermoelectric device 16, and determine that a valve operated by pilot valve operator 14 is in an open state based on a decrease in the electrical energy received from thermoelectric device 16. Similarly, microprocessor 22 may determine that a valve operated by pilot valve operator 12 has closed or deviated from the open state based on an decrease in the electrical energy received from thermoelectric device 16, and determine that a valve operated by pilot valve operator 14 has closed or deviated from an open state based on an increase in the electrical energy received from thermoelectric device 16. If thermoelectric device 16 is a device generating electrical power based on a temperature difference between a cold junction and a hot junction, the location of thermoelectric device 16 within a water heating system might result in a pilot flame alone causing a first temperature difference, while the pilot flame in conjunction with a main burner flame (typically much larger) results in a second temperature difference distinct from the first temperature difference. This may result when the main burner flame exerts a greater thermal influence on the general environment surrounding the hot and cold junctions of thermoelectric device 16 as compared to a pilot flame alone. In this scenario, the greater thermal influence of the main burner flame may act to increase the temperature of one or both of the hot and cold junctions as compared to the pilot flame acting alone, This may reduce the temperature difference between the hot and cold junctions, and reduce the amount of electrical energy produced by thermoelectric device 16 (or thermoelectric device 66 of FIG. 1).
For example, microprocessor 22 may interpret an increase in electrical energy received from thermoelectric device 16 to a level substantially equal to the first amount of electrical energy to indicate a valve such as servo valve 134 (FIG. 2A-2C) has opened and prompted generation of a pilot flame. Microprocessor 22 may interpret a decrease in electrical energy received from thermoelectric device 16 to a level less than substantially equal to the first amount to indicate a valve such as servo valve 134 (FIG. 2A-2C) has closed or deviated from the open state, and extinguished the pilot flame. In like manner, microprocessor 22 may interpret an decrease in electrical energy received from thermoelectric device 16 from a level substantially equal to the first amount to a level substantially equal to the second amount to indicate a valve such as servo valve 152 (FIG. 2A-2C) has opened and prompted generation of a main burner flame. Microprocessor 22 may interpret an increase in electrical energy received from thermoelectric device 16 from a level substantially equal to the second amount to a level substantially equal to the first amount to indicate a valve such as servo valve 154 (FIG. 2A-2C) has closed or deviated from the open state, extinguishing the main burner flame.
In some examples, microprocessor 82 is configured to determine a picking amount of the one or more electrical parameters required to bring a control valve to an open state from a closed state. For example and as discussed, when valve 84 is a solenoid valve comprising a solenoid and a plunger and valve operator 84 is the solenoid, microcontroller 82 may initially provide a picking amount of the one or more electrical parameters to valve operator 84, in order to establish a pick current in the coils of operator 84 and bring the plunger to an open state. Microprocessor 82 may subsequently provide a holding amount of the one of more electrical parameters, in order to establish a generally lower hold current in the coils of operator 84 to maintain the plunger in the open state. In some examples, microprocessor 82 may be configured to periodically determine a picking amount required to establish a pick current to flow through a valve operator. Microprocessor 82 may be configured to periodically determine the picking amount in addition to periodically determining the holding amount for a valve operator.
An example technique a controller may perform to periodically determine a picking amount of the one or more electrical parameters might comprise providing a picking amount of the one or more electrical parameters sufficient to transition the valve from a closed state to an open state. The picking amount may be based on a picking amount previously determined by the controller. The picking amount of the one or more electrical parameters may include one or more of a voltage and a current. The controller may cause a current to flow through valve operator based on the one or more electrical parameters. The controller may receive a signal indicative of a temperature T_REF.
After providing the picking amount of the one or more electrical parameters, the controller may determine that the valve is open. The controller may determine the valve is open based on an amount of electrical energy generated by a thermoelectric device. The controller may determine when the valve is open based on a voltage supplied to a valve operator establishing a position of the valve. The controller may determine when the valve is open based on a current supplied to a valve operator. The controller may determine the valve is open based on an inductive signal of the valve operator.
If the controller verifies the valve is open, the controller may then terminate providing electrical power to the valve, allowing the valve to close. The controller may then revise the one or more electrical parameters of the picking amount. For example, the controller may revise the one or more electrical parameters of the picking amount such that a pick current provided to the valve decreases. The controller may then repeat the process as long as a verification indicates the valve is open.
If the valve is not open, the controller may finalize the picking amount of the one or more electrical parameters. For example. The controller may finalize the picking amount based on an amount of the one or more electrical parameters which produced an open verification. The controller may finalize the picking amount based on the most recent amount of the one or more electrical parameters which produced an open verification. The controller may also finalize the picking amount of the one or more electrical parameters based on an amount of the one or more electrical parameters which produced a non-open state. For example, the controller may finalize the picking amount of the one or more electrical parameters based on the most recent one or more electrical parameters which produced a non-open state. The controller may associate the finalize picking amount of the one or more electrical parameters with the signal indicative of the temperature T_REF.
An example technique for determining one or more electrical parameters to be delivered to a valve is illustrated at FIG. 5. The technique may include generating electrical power using a thermoelectric device converting thermal energy from a flame into electrical energy (422). The technique may include delivering, using the controller, a quantity of the electrical power to a valve operator configured to hold a valve in an open state while receiving the quantity of electrical power (424).
The technique may further include monitoring, using the controller, whether the valve is in the open state (426). The technique may include monitoring the open state using at least one of an amount of electrical power received from the thermoelectric device, a voltage provided to the valve operator, a current provided to the valve operator, and an inductive signature of the valve operator. The technique may further include determining, using the controller, one or more electrical parameters of the quantity of electrical power required by the valve operator to hold the valve in the open state (428). The technique may further include causing, using the controller, the determined one or more electrical parameters to be delivered to the valve operator (430).
In an example, periodically determining the one or more electrical parameters includes decreasing, using the controller, the one or more electrical parameters until the valve deviates from the open state, thereby determining a closing amount of the one or more electrical parameters, and subsequently revising, using the controller, the quantity of electrical power provided to the valve operator based on the closing amount of the one or more electrical parameters.
In examples, when a flame such as the pilot flame is in thermal communication with a gas flow, or a gas flow is in thermal communication with a flame, this means the flame generates a heat flux and the heat flux impinges on some portion of the gas flow. In examples, the heat flux of the flame is sufficient to generate combustion within the portion of the gas flow. In examples, when thermoelectric device 16 is in thermal communication with a flame, the flame generates a heat flux and some portion of the heat flux impinges on some part of thermoelectric device 16. In examples, the heat flux of the flame is sufficient to cause thermoelectric device 16 to convert some portion of the heat flux into electrical energy.
In examples, one or more of pilot valve operator 12 and main valve operator 14 are millivoltage automatic valve operators. In examples, one or more of pilot valve operator 12 and main valve operator 14 are configured to alter the position of a valve when receiving power at less than 750 mV. In examples, one or more of pilot valve operator 12 and main valve operator 14 cause the opening of a valve when in an energized state. In some examples, one or more of pilot valve operator 12 and main valve operator 14 cause the closing of a valve when in the de-energized state. In some examples, one or more of pilot valve operator 12 and main valve operator 14 control the energizing of an electromechanical device such as a solenoid valve.
In examples, convertor 18 may be a power convertor which receives electrical power is a first form and converts the electrical power to another form. Converter 16 may be an electronic circuit, electronic device, or electromechanical device. In examples, converter 16 receives a first voltage received from thermoelectric device 16 and provides a second voltage to electrical line 39. In examples, the second voltage is greater than the first voltage. For example, convertor 18 might receive a first voltage of about 0.7 VDC (700 mV) from thermoelectric device 16 and provide a voltage of about 3.3 VDC to electrical line 39. In examples, convertor 18 is a DC step-up convertor.
In examples, thermoelectric device 16 comprises one or more components which generate an output voltage proportional to a local temperature difference or temperature gradient, such as a thermopile, thermocouple, or other thermoelectric generator. Thermoelectric device 16 may comprise a thermoelectric material. Thermoelectric device 16 may comprise a plurality of thermocouples connected in series or in parallel. Thermoelectric device 16 may comprise one or more thermocouple pairs. In examples, a heat flux from a pilot flame generates a temperature gradient, and thermoelectric device 16 generates a DC voltage in response to the temperature gradient.
In examples, energy storage system 20 comprises one or more of a capacitor and a battery. Energy storage system 20 may comprise a supercapacitor. Energy storage system 20 may comprise an electrochemical double-layer capacitor (EDLC). Energy storage system 20 may comprise one or more of a double-layer capacitor, a pseudocapacitor, and a hybrid capacitor.
In examples, microcontroller 22 may include any one or more of a microcontroller (MCU), e.g. a computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals, a microcontroller (μP), e.g. a central processing unit (CPU) on a single integrated circuit (IC), a controller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a system on chip (SoC) or equivalent discrete or integrated logic circuitry. A processor may be integrated circuitry, i.e., integrated processing circuitry, and that the integrated processing circuitry may be realized as fixed hardware processing circuitry, programmable processing circuitry and/or a combination of both fixed and programmable processing circuitry.
In one or more examples, functions described herein may be implemented in hardware, software, firmware, or any combination thereof. For example, the various components and functions of FIGS. 1-5 may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on a tangible computer-readable storage medium and executed by a processor or hardware-based processing unit.
Instructions may be executed by one or more processors, such as one or more DSPs, general purpose microcontrollers, ASICs, FPGAs, or other equivalent integrated or discrete logic circuitry. Accordingly, the term “processor,” as used herein, such as may refer to any of the foregoing structure or any other structure suitable for implementation of the techniques described herein. Also, the techniques could be fully implemented in one or more circuits or logic elements.
The techniques of this disclosure may be implemented in a wide variety of devices or apparatuses, including a wireless handset, an integrated circuit (IC) or a set of ICs (e.g., a chip set). Various components, modules, or units are described in this disclosure to emphasize functional aspects of devices configured to perform the disclosed techniques, but do not necessarily require realization by different hardware units. Rather, as described above, various units may be combined in a hardware unit or provided by a collection of interoperative hardware units, including one or more processors as described.
The present disclosure includes the following examples:
Example 1: A water heater comprising: a thermoelectric device that converts thermal energy to electrical energy to power components of the water heater; a valve configured to control whether there is a gas flow to cause a flame; and a controller configured to: receive power from the electrical energy generated by the thermoelectric device; periodically determine one or more electrical parameters for holding the valve in an open state based at least in part on information indicative of whether the valve is in the open state; and cause a current to flow through the valve based on the determined one or more electrical parameters.
Example 2: The water heater of example 1, wherein the information indicative of whether the valve is in the open state is an amount of the electrical energy generated by the thermoelectric device, and wherein the controller is configured to determine the amount of the electrical energy generated by the thermoelectric device.
Example 3: The water heater of example 1 or 2, wherein the information indicative of whether the valve is in the open state is an increase or a decrease in the amount of the electrical energy generated by the thermoelectric device, and wherein the controller is configured to determine the increase or the decrease in the amount of the electrical energy generated by the thermoelectric device.
Example 4: The water heater of any of examples 1-3, wherein the information indicative of whether the valve is in the open state is at least one of a voltage supplied to the valve, an inductive signature of the valve, or a current supplied to the valve, wherein the controller is configured to determine one or more of the voltage supplied to the valve, the inductive signature of the valve, or the current supplied to the valve.
Example 5: The water heater of any of examples 1-4, further comprising a temperature sensor, wherein the controller is configured to receive a temperature signal from the temperature sensor when the controller periodically determines the one or more electrical parameters.
Example 6: The water heater of example 5, wherein the controller associates the determined one or more electrical parameters with the temperature signal.
Example 7: The water heater of example 6, wherein the controller causes the current to flow through the valve based at least in part on the temperature signal.
Example 8: The water heater of any of examples 1-7, wherein the valve is a solenoid operated valve comprising a solenoid and a plunger, and wherein when the controller causes the current to flow through the valve, the current flows through the solenoid.
Example 9: The water heater of any of examples 1-8, wherein the thermoelectric device converts thermal energy from a pilot flame to electrical energy, and wherein the gas flow is a main gas flow in thermal communication with the pilot flame, and wherein the flame is a main burner flame caused by the thermal communication between the pilot flame and the main gas flow.
Example 10: The water heater of example 9, wherein the pilot flame is caused by a pilot gas flow and further comprising: a second valve configured to control whether there is the pilot gas flow, wherein the controller is configured to, periodically determine a second set of the one or more electrical parameters for holding the second valve in an open state based at least in part on information indicative of whether the second valve is in the open state, and cause a current to flow through the second valve based on the determined second set of the one or more electrical parameters.
Example 11: The water heater of example 10, further comprising: an energy storage system, wherein the energy storage system is configured to receive a first portion of the electrical energy from the thermoelectric device, wherein the second valve is configured to receive electrical energy from the energy storage system and configured to receive a second portion of the electrical energy from the thermoelectric device, and wherein the valve is configured to receive a third portion of the electrical energy from the thermoelectric device.
Example 12: The water heater of any of examples 1-11, wherein the valve is configured to hold in the open state while receiving a holding amount of the one or more electrical parameters, and wherein the controller is configured to: determine when the valve deviates from the open state; provide the holding amount of the one or more electrical parameters and hold the valve in the open state; alter the one or more electrical parameters of the holding amount until the valve deviates from the open state, thereby determining a dropping amount of the one or more electrical parameters; and revise the holding amount of the one or more electrical parameters based on the dropping amount of the one or more electrical parameters, thereby periodically determining the one or more electrical parameters for holding the valve in the open state.
Example 13: The water heater of example 12, wherein the controller is configured to determine when the valve deviates from the open state using at least one of the electrical energy generated by the thermoelectric device, a voltage supplied to the valve, an inductive signature of the valve, or a current supplied to the valve.
Example 13: The water heater of examples 12 or 13, further comprising a temperature sensor, wherein the controller is configured to receive a temperature signal from the temperature sensor, and wherein the controller is configured to associate the revised sufficient amount of the one or more electrical parameters with the temperature signal.
Example 14: A water heater comprising: a thermoelectric device configured to convert thermal energy from a flame to generate electrical energy to power components of the water heater; a valve having a valve operator, wherein the valve operator is configured to receive electrical power and cause the valve to hold an open state; a temperature sensor; and a controller configured to: receive power from the electrical energy generated by the thermoelectric device when the flame is present and receive power from a stored energy system when the pilot flame is not present; receive a temperature signal from the temperature sensor; periodically determine one or more electrical parameters of the electrical power required by the valve operator to cause the valve to hold an open state based at least in part on information indicative of whether the valve is in the open state; associate the determined one or more electrical parameters with the temperature signal; and provide the electrical power to the valve operator based on the determined one or more electrical parameters and the temperature signal.
Example 16: The water heater of example 15, wherein the controller is configured to: facilitate the electrical power to the valve operator and allow the valve operator to cause the valve to hold the open state; determine when the valve deviates from the open state; decrease, with the valve in the open state, the one or more electrical parameters of the electrical power until the valve deviates from the open state, thereby determining a closing amount of the one or more electrical parameters; and revise the electrical power provided to the valve operator based on the closing amount of the one or more electrical parameters and the temperature signal, thereby periodically determining the one or more electrical parameters of the electrical power required by the valve operator to cause the valve to hold the open state.
Example 17: The water heater of example 16, wherein the controller is configured to determine when the valve deviates from the open state using at least one of the electrical energy generated by the thermoelectric device, a voltage supplied to the valve operator, an inductive signature of the valve operator, or a current supplied to the valve operator.
Example 18: The water heater of any of examples 15-17, wherein the thermoelectric device converts thermal energy from a pilot flame to electrical energy, wherein the valve is configured to control a pilot gas flow causing the pilot flame, and further comprising: a second valve configured to control a main gas flow causing a main burner flame using the pilot flame, wherein the controller is configured to, periodically determine a second set of the one or more electrical parameters for holding the second valve in the open state based at least in part on information indicative of whether the second valve is in the open state, and cause a current to flow through the second valve based on the determined second set of the one or more electrical parameters.
Example 19: A method comprising: generating electrical power using a thermoelectric device converting thermal energy from a flame into electrical energy; delivering, using the controller, a quantity of the electrical power to a valve operator configured to hold a valve in an open state while receiving the quantity of electrical power; monitoring, using the controller, whether the valve is in the open state; determining, using the controller, one or more electrical parameters of the quantity of electrical power required by the valve operator to hold the valve in the open state; and causing, using the controller, the determined one or more electrical parameters to be delivered to the valve operator.
Example 20: The method of claim 19, further comprising: decreasing, using the controller, the one or more electrical parameters until the valve deviates from the open state, thereby determining a closing amount of the one or more electrical parameters; revising, using the controller, the quantity of electrical power provided to the valve operator based on the closing amount of the one or more electrical parameters, thereby periodically determining the one or more electrical parameters of the quantity of the electrical power required by valve operator to hold the valve in the open state.
Various examples have been described. These and other examples are within the scope of the following claims.

Claims

What is claimed is:

1. A water heater comprising:

a thermoelectric device that converts thermal energy to electrical energy to power components of the water heater;

a valve configured to control whether there is a gas flow to cause a flame; and

a controller configured to:

receive power from the electrical energy generated by the thermoelectric device;

periodically determine one or more electrical parameters for holding the valve in an open state based at least in part on information indicative of whether the valve is in the open state; and

cause a current to flow through the valve based on the determined one or more electrical parameters.

2. The water heater of claim 1, wherein the information indicative of whether the valve is in the open state is an amount of the electrical energy generated by the thermoelectric device, and wherein the controller is configured to determine the amount of the electrical energy generated by the thermoelectric device.

3. The water heater of claim 2, wherein the information indicative of whether the valve is in the open state is an increase or a decrease in the amount of the electrical energy generated by the thermoelectric device, and wherein the controller is configured to determine the increase or the decrease in the amount of the electrical energy generated by the thermoelectric device.

4. The water heater of claim 1, wherein the information indicative of whether the valve is in the open state is at least one of a voltage supplied to the valve, an inductive signature of the valve, or a current supplied to the valve, wherein the controller is configured to determine one or more of the voltage supplied to the valve, the inductive signature of the valve, or the current supplied to the valve.

5. The water heater of claim 1 further comprising a temperature sensor, wherein the controller is configured to receive a temperature signal from the temperature sensor when the controller periodically determines the one or more electrical parameters.

6. The water heater of claim 5 wherein the controller associates the determined one or more electrical parameters with the temperature signal.

7. The water heater of claim 6, wherein the controller causes the current to flow through the valve based at least in part on the temperature signal.

8. The water heater of claim 1, wherein the valve is a solenoid operated valve comprising a solenoid and a plunger, and wherein when the controller causes the current to flow through the valve, the current flows through the solenoid.

9. The water heater of claim 1, wherein the thermoelectric device converts thermal energy from a pilot flame to electrical energy, and wherein the gas flow is a main gas flow in thermal communication with the pilot flame, and wherein the flame is a main burner flame caused by the thermal communication between the pilot flame and the main gas flow.

10. The water heater of claim 9 wherein the pilot flame is caused by a pilot gas flow and further comprising:

a second valve configured to control whether there is the pilot gas flow, wherein the controller is configured to,

periodically determine a second set of the one or more electrical parameters for holding the second valve in an open state based at least in part on information indicative of whether the second valve is in the open state, and

cause a current to flow through the second valve based on the determined second set of the one or more electrical parameters.

11. The water heater of claim 10 further comprising:

an energy storage system,

wherein the energy storage system is configured to receive a first portion of the electrical energy from the thermoelectric device,

wherein the second valve is configured to receive electrical energy from the energy storage system and configured to receive a second portion of the electrical energy from the thermoelectric device, and

wherein the valve is configured to receive a third portion of the electrical energy from the thermoelectric device.

12. The water heater of claim 1, wherein the valve is configured to hold in the open state while receiving a holding amount of the one or more electrical parameters, and wherein the controller is configured to:

determine when the valve deviates from the open state;

provide the holding amount of the one or more electrical parameters and hold the valve in the open state;

alter the one or more electrical parameters of the holding amount until the valve deviates from the open state, thereby determining a dropping amount of the one or more electrical parameters; and

revise the holding amount of the one or more electrical parameters based on the dropping amount of the one or more electrical parameters, thereby periodically determining the one or more electrical parameters for holding the valve in the open state.

13. The water heater of claim 12 wherein the controller is configured to determine when the valve deviates from the open state using at least one of the electrical energy generated by the thermoelectric device, a voltage supplied to the valve, an inductive signature of the valve, or a current supplied to the valve.

14. The water heater of claim 12 further comprising a temperature sensor, wherein the controller is configured to receive a temperature signal from the temperature sensor, and wherein the controller is configured to associate the revised sufficient amount of the one or more electrical parameters with the temperature signal.

15. A water heater comprising:

a thermoelectric device configured to convert thermal energy from a flame to generate electrical energy to power components of the water heater;

a valve having a valve operator, wherein the valve operator is configured to receive electrical power and cause the valve to hold an open state;

a temperature sensor; and

a controller configured to:

receive power from the electrical energy generated by the thermoelectric device when the flame is present and receive power from a stored energy system when the pilot flame is not present;

receive a temperature signal from the temperature sensor;

periodically determine one or more electrical parameters of the electrical power required by the valve operator to cause the valve to hold an open state based at least in part on information indicative of whether the valve is in the open state;

associate the determined one or more electrical parameters with the temperature signal; and

provide the electrical power to the valve operator based on the determined one or more electrical parameters and the temperature signal.

16. The water heater of claim 15, wherein the controller is configured to:

facilitate the electrical power to the valve operator and allow the valve operator to cause the valve to hold the open state;

determine when the valve deviates from the open state;

decrease, with the valve in the open state, the one or more electrical parameters of the electrical power until the valve deviates from the open state, thereby determining a closing amount of the one or more electrical parameters; and

revise the electrical power provided to the valve operator based on the closing amount of the one or more electrical parameters and the temperature signal, thereby periodically determining the one or more electrical parameters of the electrical power required by the valve operator to cause the valve to hold the open state.

17. The water heater of claim 16 wherein the controller is configured to determine when the valve deviates from the open state using at least one of the electrical energy generated by the thermoelectric device, a voltage supplied to the valve operator, an inductive signature of the valve operator, or a current supplied to the valve operator.

18. The water heater of claim 15, wherein the thermoelectric device converts thermal energy from a pilot flame to electrical energy, wherein the valve is configured to control a pilot gas flow causing the pilot flame, and further comprising:

a second valve configured to control a main gas flow causing a main burner flame using the pilot flame, wherein the controller is configured to,

periodically determine a second set of the one or more electrical parameters for holding the second valve in the open state based at least in part on information indicative of whether the second valve is in the open state, and

19. A method comprising:

generating electrical power using a thermoelectric device converting thermal energy from a flame into electrical energy;

delivering, using the controller, a quantity of the electrical power to a valve operator configured to hold a valve in an open state while receiving the quantity of electrical power;

monitoring, using the controller, whether the valve is in the open state;

determining, using the controller, one or more electrical parameters of the quantity of electrical power required by the valve operator to hold the valve in the open state; and

causing, using the controller, the determined one or more electrical parameters to be delivered to the valve operator.

20. The method of claim 19 further comprising:

decreasing, using the controller, the one or more electrical parameters until the valve deviates from the open state, thereby determining a closing amount of the one or more electrical parameters;

revising, using the controller, the quantity of electrical power provided to the valve operator based on the closing amount of the one or more electrical parameters, thereby periodically determining the one or more electrical parameters of the quantity of the electrical power required by valve operator to hold the valve in the open state.