Water Heater with Intermittent Pilot and Damper Control

This application claims priority to U.S. Provisional Application No. 63/658,524, filed on Jun. 11, 2024, entitled “WATER HEATER WITH INTERMITTENT PILOT AND DAMPER CONTROL,” the disclosure of which is hereby incorporated herein by reference in its entirety.

The present invention relates generally to a water heater, and more particularly, to an energy-sustaining gas water heater.

Although many improvements to water heating systems have been made over the years, there remains a need for further improvements in terms of, for example, improved performance, improved efficiency, cost effectiveness, and/or ease of use.

According to a first aspect of the present disclosure, a water heater is provided comprising a water storage tank defining an interior region configured to contain water to be heated; a heat source configured to generate heat for transfer to water when contained in the interior region of the water storage tank, the heat source including a gas burner configured to generate combustion gases; a flue extending through the interior region of the water storage tank and configured to exhaust the combustion gases generated by the gas burner; a temperature sensor positioned to directly or indirectly sense a temperature of the water when contained in the interior region of the water storage tank; a pilot associated with the gas burner and configured to fire the gas burner; a pilot valve configured to supply gas to the pilot; an intermittent spark generator associated with the pilot and configured to ignite a pilot flame; a thermoelectric element configured to generate energy from the pilot flame; a main valve associated with the gas burner and configured to supply gas to the gas burner; a damper extending within the flue and configured to move between a closed position to restrict the flow of the combustion gases through the flue and an open position to allow the flow of the combustion gases through the flue; and a controller coupled to the temperature sensor, the pilot valve, the intermittent spark generator, the thermoelectric element, and the damper. The controller is configured to: actuate the intermittent spark generator to ignite the pilot flame of the pilot after a first predetermined condition is satisfied, move the damper toward the open position when the energy generated by the thermoelectric element exceeds a threshold value, and open the main valve to permit flow of gas to the gas burner after the damper is in the open position and after a second predetermined condition is satisfied. The first predetermined condition is different from the second predetermined condition, and the first predetermined condition is selected to be satisfied before the second predetermined condition is satisfied.

Embodiments of the first aspect of the present disclosure can include any one or a combination of the following features:

According to a second aspect of the present disclosure, a method of firing a water heater is provided. The water heater includes a gas burner coupled to receive gas via a main valve, a pilot coupled to receive gas via a pilot valve, an intermittent spark generator positioned to spark the pilot, a thermoelectric element, a flue, and a damper configured to move between a closed position and an open position relative to the flue. The method comprises the steps of: actuating the intermittent spark generator to ignite a pilot flame of the pilot after a first predetermined condition is satisfied, generating a threshold value of energy in the thermoelectric element via the pilot flame, moving the damper toward the open position when the threshold value of energy reaches the threshold value thus permitting combustion gases to flow through the flue, and opening the main valve to permit flow of gas to the gas burner after the damper is in the open position and after a second predetermined condition is satisfied. The first predetermined condition is different from the second predetermined condition, and the first predetermined condition is selected to be met before the second predetermined condition.

Embodiments of the second aspect of the present disclosure can include any one or a combination of the following features:

According to a third aspect of the present disclosure, a controller for a water heater is provided. The water heater includes a water storage tank defining an interior region configured to contain water to be heated, a heat source including a gas burner including a pilot, a pilot valve, an intermittent spark generator, and a main valve, a thermoelectric element, and a damper configured to move between a closed position and an open position. The controller comprises a memory; a processor coupled to the memory; and programming stored in the memory. Execution of the programming by the processor configures the controller to: actuate the intermittent spark generator to ignite a pilot flame of the pilot when a first predetermined condition is satisfied, move the damper toward the open position when an energy generated by the thermoelectric element from the pilot flame exceeds a threshold value, and open the main valve to permit flow of gas to the gas burner after the damper is in the open position and after a second predetermined condition is satisfied. The first predetermined condition is different from the second predetermined condition, and the first predetermined condition is selected to be met before the second predetermined condition.

According to a fourth aspect of the present disclosure, a method for retrofitting a water heater is provided. The water heater includes a water storage tank defining an interior region configured to contain water to be heated, a flue, and a heat source including a gas burner, a pilot, a pilot valve, and a main valve. The method comprises the steps of: providing the water heater with an intermittent spark generator for igniting the pilot valve, a thermoelectric element, and a damper configured to move relative to the flue between a closed position and an open position; and providing a controller configured for: actuating the intermittent spark generator to ignite a pilot flame of the pilot when a first predetermined condition is satisfied, moving the damper toward the open position when an energy generated by the thermoelectric element from the pilot flame exceeds a threshold value, and opening the main valve to permit flow of gas to the gas burner after the damper is in the open position and after a second predetermined condition is satisfied. The first predetermined condition is different from the second predetermined condition, and the first predetermined condition is selected to be met before the second predetermined condition.

Embodiments of the fourth aspect of the present disclosure can include any one or a combination of the following features:

These and other features, advantages, and objects of the present disclosure will be further understood and appreciated by those skilled in the art by reference to the following specification, claims, and appended drawings.

Although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the invention.

The invention is best understood from the following detailed description when read in connection with the accompanying drawing figures, which shows exemplary embodiments of the invention selected for illustrative purposes. The invention will be illustrated with reference to the figures. Such figures are intended to be illustrative rather than limiting and are included herewith to facilitate the explanation of the present invention.

According to some embodiments of the invention, an improved water heater is provided in which energy can be sustained within the water heater to allow for the reliable operation of the water heater even in the event of a power failure. For example, in some embodiments of the invention, the water heater can sustain energy during the standby mode and the recovery mode and/or power energy-saving devices while minimizing energy loss and controlling the stored water temperature.

In some embodiments of the invention, this may be accomplished without the use of external electric power, because the water heater can sustain the energy needed to power a damper while in the standby mode. For example, embodiments of the present invention can include damper control so that a pilot is not ignited all the time.

Referring now to the figures, selected embodiments of the invention are illustrated as non-limiting examples.

An exemplary embodiment of a water heateris illustrated in. Referring to, the water heaterincludes a tankconfigured to store water to be heated. Although a gas-fired storage water heater is selected for purposes of illustration, the invention is not limited to gas-fired water heaters or to storage water heaters and can be applied to other forms of water heaters. Also, the invention can be utilized in residential, commercial, or other water heating systems.

The tankof illustrated water heaterhas a wall with an external surface and an internal surface defining an interior region() configured to contain water to be heated. The water heaterincludes a heat source() including a gas burnerconfigured to generate combustion gases, a controller(), and a temperature sensor(e.g., a thermistor) or a thermostat (e.g., bimetallic or thermocouple-based thermostat) that is thermally coupled to (e.g., physically contacting) a wall portion of the water tankand that monitors the temperature of the water in the water heater. Temperature sensoris preferably located in an opening on tankto directly or indirectly sense the temperature of the water when contained in the interior regionof the water storage tank.

Referring now to, the water heaterincludes a pilot burnerassociated with the gas burnerand a pilot valveconfigured to supply gas to the pilot burner. Additionally, the heatercan include a gas valveconfigured to permit or prevent, or limit flow of gas to the gas burner. The controlleris configured to operate the gas valvein response to a demand for heat signal. A pilot and thermopile assemblyincludes the pilot burnerand two thermo-voltaic devicesandlocated proximally thereto. Pilot burneris lit when the water heater is brought into operation. For example, an intermittent spark generator, including, e.g., a spark coil, a transformer, an electrical circuit, and/or a spark plug, can be associated with the pilot burnerand configured to ignite a pilot flame.

The pilot flame from pilot burner, which may or may not be in contact with thermo-voltaic devicesand, provides heat energy to thermo-voltaic devicesand, which thereby generate electrical energy from the pilot flame. Thermo-voltaic devicesandpreferably comprise thermopiles, but are not necessarily limited thereto. The operation of thermopiles is well known to those of ordinary skill in the art and will not be further elaborated upon here except to note that the voltage produced by thermo-voltaic devicesandis preferably in the milli-volt (mV) range.

While two thermopiles are shown in, those of ordinary skill in the art will appreciate that more or fewer thermopiles may be used depending on the voltage and current required and the performance characteristics of thermopiles used. However, by using two or even more thermopiles in the manner illustrated, the output from a single pilot burner can be maximized while keeping the overall size of the pilot assembly to a minimum.

Thermo-voltaic devicesandare preferably, but not necessarily, wired in series if plural devices are used. Lead wiresandfor thermo-voltaic deviceare connected to the gas valve, and the lead wirefor the thermo-voltaic deviceis connected to the gas valve, with wirefor the devicebeing connected to the thermostatto provide power thereto, as shown. Thermo-voltaic devicesupplies the power needed to hold open the pilot valvelocated in the gas valve.

When thermostatdetects the need to heat the water, it closes the circuit between wiresupplying power to the thermostatfrom thermo-voltaic devicesandand wireleading from thermostatto damper, which is normally in a closed position. As a result of this completed circuit, power is delivered to damper motor, causing damper vaneto move into the full open vertical position.

When damper vanereaches the full open vertical position, switchesandare actuated. Switchopens the circuit, providing power to the motor and acts in series with switchto complete a circuit providing power to main gas valve. Main gas valvethen opens supplying gas through manifoldto the main burners, and main burnersare ignited by the pilot flame. The gas is burned in the combustion chamber. The products of combustion rise through the flue tubes, collector, and opened flue damper. The passage of exhaust gases from the at least one main burneris controlled with flueand flue damper. The combustion products then exit the water heater through draft diverterinto the installation's venting system (not shown).

When the temperature of the water in the tank reaches the set point of thermostat, thermostatswitches, opening the circuit between wiresupplying power to the thermostat and wireleading to switchin the flue damper, and closing the circuit between wiresupplying power to the thermostatand wireconnected to a thermal switch. Thermal switchis coupled to flue damper. Thermal switchdetermines whether the at least one main burneris firing after the temperature of the water in the tank reaches the set point of thermostat. It is contemplated that thermal switchmay determine whether the at least one main burneris firing by sensing whether a temperature proximate to the main burner is equal to or greater than a predetermined threshold temperature.

If the at least one main burneris determined to be firing, flue damperis controlled to remain open, as shown at step. For example, if main gas valvewere to remain open after the temperature of the water in the tank reaches the set point of thermostat, thermal switchwould continue to sense heat from the main burnersand remain open. If thermal switchremains open, the circuit is not completed, power is not supplied to damper motor, and damper vaneremains in the open position.

Alternatively, if the at least one main burneris determined to not be firing, flue damperis controlled to close, as shown at step. When thermal switchno longer senses heat from the main burner or burners, thermal switchcloses, completing a circuit between thermostatand wireleading to damper. The completion of this circuit supplies power to damper motorso that damper vanemoves to the closed position. When damper vanemoves to the closed position, switchopens, interrupting power to damper motor.

If the damper vaneis caused to move to the closed position, the damper vanepreferably remains closed while the water heater is in standby, reducing energy loss from the water heater. Pilot burnercontinues to burn so that the energy is available for another cycle when the water in the tankbecomes cold enough to again activate the thermostat, without the need for an external source of power to operate damper motor.

When power is interrupted in the circuit leading to switchin the flue damper, the power to main gas valveis interrupted. An exemplary thermal switch may be Model No. 36TXVG11 of Thermodisc, Inc., of 1320 South Main Street, Mansfield, OH 44907. Other switches are optionally used.

In general, the controllerillustrated incan include devices such as a microprocessor, memory devices, analog input/output (I/O), digital I/O, power regulation, etc. (not shown), which serve to perform various operations. For example, such operations may include operations related to collecting and recording temperatures from temperature sensorand acting upon those temperatures to control the intermittent spark generator to ignite the pilot flame of the pilot, movement of the damperbetween the closed and the open positions, and opening or closing the main valve to permit or stop flow of gas to the gas burner. The controlleris operatively coupled to the temperature sensor, the heat source, the pilot valve, the spark ignition system, the thermoelectric elementsand, the main valve, and the damper.

The memory of the controllergenerally stores the programming for the controller. Specifically, the memory stores instructions that, when executed by the controller, cause the controllerto provide functionality related to actuating the intermittent spark generator to ignite the pilot flame of the pilot, moving the damper toward the open position when the energy generated by the thermoelectric element exceeds a threshold value, and opening the main valve to permit flow of gas to the gas burner after the damper is in the open position and after a predetermined condition is satisfied, temperature detection programming, temperature indicator programming, etc. To facilitate these programs, the memory also stores temperature records comprising the time, temperature, and the rate of change in temperature of the water. For example, the memory stores various values, including but not limited to setpoint temperature of the water contained in the interior regionof the water storage tank, temperature thresholds, thermopile energy thresholds, rate of change of the temperature, predetermined time periods, etc.

illustrates an overall method of heating water with a water heater according to an exemplary embodiment of the invention. As shown at step, the water heater is in a standby mode, in which the thermostat is satisfied, the pilot is off, the main burner is off, and the damper is closed. As shown at step, thermostatdetects a “call for heat,” for example, when a temperature and/or a flow and/or a pressure sensed by the temperature and/or flow and/or pressure sensor is below a setpoint (e.g., set by the user with a setpoint temperature knob for setting a desired setpoint temperature of the water) or prescribed temperature or flow or pressure. A call for heat may relate to the gas valve, which can have a temperature sensor (e.g., thermistor, RTD, thermocouple, etc.) that is in a shank/thermal well of the gas valve that is monitoring the water temperatures and the rate of change in temperature of the water. As the electro/mechanical controller(s) senses, calculates and/or gas valve sees either a rate of change of water temperature over time, or water temperatures below a certain temperature, it can charge a solenoid to open the flow path for gas to travel through a feed and/or pilot ultimately lighting the burner. When the electro/mechanical controller(s) starts the process of lighting a burner based on information or a signal from a temperature sensor (or electro/mechanical controller logic/device) it can be considered a “call for heat”.

As shown at step, in response to the “call for heat”, the pilot valveopens, and an intermittent spark ignition generator associated with the pilotignites a pilot flame using energy from stored energy source (e.g., from a rechargeable battery). The pilot flame is ignited when a first predetermined condition is satisfied. The first predetermined condition is satisfied when the temperature of the water contained in the interior region of the water storage tank drops at a rate above (e.g., faster than) a predetermined rate of temperature change. For example, the first predetermined condition is satisfied when a ratio between a change (e.g., delta) dTwe in the temperature of the water contained in the interior region of the water storage tank over a time dT of this change in temperature is above (e.g., faster or greater than) a predetermined rate of temperature change measured in degrees Fahrenheit per second, such as 0.05° F. (degrees Fahrenheit) per second, for example:

As shown at step, thermopile assemblyincluding the thermo-voltaic devicesandreceives heat energy from the flame generated by pilot burner, and converts a portion of that heat energy into electrical energy. Numerous thermopile devices are commercially available and may be used herein. For example, thermopile assemblyis capable of generating about 350 mv. This electrical energy is supplied to gas valveby wires,and,. Thermopile assemblyprovides a continuous source of electricity to the entire electrical system connected to gas valve. The pilot burnerheats the thermopile assemblyuntil a threshold voltage of about 350 mV is generated.

Because there is typically a delay in time of about two minutes as the thermopile assemblyheats up until it generates the threshold voltage of about 350 mV, embodiments of the present invention provide an energy efficient solution of monitoring the rate of water temperature change (e.g., drop) or water temperature differentials, not only the water temperature relative to a setpoint water temperature, to ignite the pilot burnerto start charging the thermopile assemblyearly enough before the temperature of the water drops below the setpoint water temperature.

As shown at step, when the threshold voltage of about 350 mV is generated, a controller routes the electrical energy from the thermopile assemblyand starts moving the flue damperfrom the closed position toward the open position. When a second predetermined condition is satisfied, the controller opens the main valve to permit flow of gas to the gas burner after the flue damperis in the open position.

The second predetermined condition is satisfied when the temperature of the water contained in the interior region of the water storage tank drops below a predetermined difference between a setpoint temperature of the water contained in the interior region of the water storage tank and a second differential temperature of the water contained in the interior region of the water storage tank, where the first differential temperature is smaller than the second differential temperature.

The controller moves the flue damperfrom the normally closed damper position to the open damper position preferably using only the electricity generated by the thermoelectric element (e.g., thermopile assembly).

As shown at step, a damper switch (e.g., switchesand) coupled to the controller is configured to send to the controller a “fully open” signal related to the open position of the flue damper.

As shown at step, the controller switches power from the flue damperto open the main gas valve, in response to the “fully open” damper signal, preferably using only energy generated by the thermoelectric element (e.g., thermopile assembly).

As shown at step, the controller ignites the main gas burner, preferably using only energy generated by the thermoelectric element (e.g., thermopile assembly).

illustrates an overall method of heating water with a water heater according to an exemplary embodiment of the invention. As shown at step, the water heater is in a recovery mode, in which the thermostat sees a “call for heat”, the pilot is on, the main burner is on, and the damper is open. As shown at step, thermostatdetects that the “call for heat” has been satisfied, for example, when a temperature and/or a flow and/or a pressure sensed by the temperature and/or flow and/or pressure sensor is at or above the setpoint or prescribed temperature or flow or pressure.

As shown at step, in response to the “call for heat” satisfied detection, the main gas valvecloses, extinguishing the burner.

As shown at step, the controller routes the electrical energy from the thermopile assemblyand starts moving the flue damperfrom the open position toward the closed position.

As shown at step, the controller receives a signal from the damper indicating that the damper is closed and discontinues power to the damper.

At step, the controller shuts down the pilot valve, extinguishes the pilot flame, turns off the pilot, and discontinues the heat energy to thermopile assemblyfrom the flame generated by pilot burner.

At step, as the thermopile assemblycools down, the stored energy (e.g., in the rechargeable battery) becomes the primary energy for the water heater.

At step, the water heateris in a standby mode, in which the thermostat is satisfied, the pilot is off, the main burner is off, and the damper is closed.

illustrates a method of heating water with a water heater based on the rate of temperature change of the water contained in the interior regionof the water storage tank, according to an exemplary embodiment of the invention.