SCALE DEPOSIT DETECTION IN WATER HEATER APPLIANCES

Abstract

A water heater appliance includes a heat exchanger, a first temperature sensor disposed on a front surface of the heat exchanger, a second temperature sensor disposed on an elbow extending from the heat exchanger, and a controller. A method of operating the water heater appliance includes monitoring a first temperature of the front surface of the heat exchanger with the first temperature sensor while the water heater appliance is running, monitoring a second temperature of the elbow with the second temperature sensor when the water heater appliance stops running, calculating a difference between the first temperature and the second temperature, and determining scale buildup in the heat exchanger based on the difference between the first temperature and the second temperature.

Description

FIELD OF THE INVENTION

The present subject matter relates generally to water heater appliances, more particularly to detecting scale deposits within tankless water heater appliances.

BACKGROUND OF THE INVENTION

Tankless water heaters differ from conventional water heaters in that a large volume of heated water is not stored in a large tank but flows through a heat exchanger where the water is quickly heated. The heat exchanger may have a burner within a combustion chamber that provides the heat to the water flowing through the heat exchanger. The combustion products, such as exhaust, then leave the system through a flue and into the outside air.

Different types of water may flow through water heaters, particularly hard water and soft water. Hard water can contain compounds and ions of calcium and magnesium which generally have good conductivity, and easily generate scale deposits. Calcium and magnesium can also help to slow down corrosion reactions inside the water heater. Soft water is formed from water softeners such as sodium or potassium replacing the calcium and magnesium. The sodium and potassium can provide better conductivity, and generate less scale deposits than hard water but provide little protection from corrosion reactions. In either case, the scale deposits will form inside the heat exchanger, leading to overheating or corrosion issues.

Accordingly, a water heater appliance configured to detect scale deposits would be advantageous to prevent overheating or corrosion issues.

BRIEF DESCRIPTION OF THE INVENTION

Aspects and advantages of the invention will be set forth in part in the following description, or may be apparent from the description, or may be learned through practice of the invention.

In one example embodiment, a water heater appliance includes a heat exchanger, a first temperature sensor disposed on a front surface of the heat exchanger, a second temperature sensor disposed on an elbow extending from the heat exchanger, and a controller. A method of operating the water heater appliance includes monitoring a first temperature of the front surface of the heat exchanger with the first temperature sensor while the water heater appliance is running, monitoring a second temperature of the elbow with the second temperature sensor when the water heater appliance stops running, calculating a difference between the first temperature and the second temperature, and determining scale buildup in the heat exchanger based on the difference between the first temperature and the second temperature.

In another example embodiment, a water heater appliance includes a heat exchanger, a first temperature sensor disposed on a front surface of the heat exchanger, a second temperature sensor disposed on an elbow extending from the heat exchanger, and a controller. The controller is configured to monitor a first temperature of the front surface of the heat exchanger with the first temperature sensor while the water heater appliance is running, monitor a second temperature of the elbow with the second temperature sensor when the water heater appliance stops running, calculate a difference between the first temperature and the second temperature, and determine scale buildup in the heat exchanger based on the difference between the first temperature and the second temperature.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures.

FIG. 1 provides a front view of an example embodiment of a tankless water heater according to aspects of the present disclosure.

FIG. 2 provides a front view of the interior of the example water heater of FIG. 1.

FIG. 3 provides a flowchart of an example method of operating a tankless water heater according to aspects of the present disclosure.

FIG. 4 provides a flowchart of another example method of operating a tankless water heater according to aspects of the present disclosure.

Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

As used herein, the terms “includes” and “including” are intended to be inclusive in a manner similar to the term “comprising.” Similarly, the term “or” is generally intended to be inclusive (i.e., “A or B” is intended to mean “A or B or both”). Approximating language, as used herein throughout the specification and claims, is applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about,” “approximately,” and “substantially,” are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. For example, the approximating language may refer to being within a ten percent (10%) margin. The terms “upstream” and “downstream” refer to the relative flow direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the flow direction from which the fluid flows, and “downstream” refers to the flow direction to which the fluid flows.

FIGS. 1 and 2 illustrate an example embodiment of a water heater appliance 100. In the present example embodiment, water heater appliance 100 may be a gas, tankless water heater appliance 100 and may be configured in the same or similar manner to known gas, tankless water heaters. As seen in FIG. 1, water heater appliance 100 may include a case 102. A controller 104 may be included in or on case 102. Controller 104 will be discussed in greater detail herein. Also shown in FIG. 1, an exhaust duct connector 106 may extend out from the interior of case 102. Referring also to FIG. 2, a heat exchanger 200 is positioned on a water line 210 disposed inside case 102. Water line 210 extends from a water inlet 108 to a water outlet 110 and may pass through heat exchanger 200 in water heater appliance 100. Water inlet 108 may be connected to a pressurized water supply, such as a well or municipal water system. Water outlet 110 may be connected to a downstream water consumption fixture, such as a dishwasher, washing machine, faucet, etc. Heat exchanger 200 may also include a burner 212, for heating up water from water line 210 passing through heat exchanger 200. Burner 212 creates combustion products, such as exhaust gases, that may exit water heater appliance 100 through exhaust duct connector 106 to ambient atmosphere.

As used herein, the terms “processing device,” “computing device,” “controller,” or the like may generally refer to any suitable processing device, such as a general or special purpose microprocessor, a microcontroller, an integrated circuit, an application specific integrated circuit (ASIC), a digital signal processor (DSP), a field-programmable gate array (FPGA), a logic device, one or more central processing units (CPUs), a graphics processing units (GPUs), processing units performing other specialized calculations, semiconductor devices, etc. In addition, these “controllers” are not necessarily restricted to a single element but may include any suitable number, type, and configuration of processing devices integrated in any suitable manner to facilitate appliance operation. Alternatively, controller 104 may be constructed without using a microprocessor, e.g., using a combination of discrete analog and/or digital logic circuitry (such as switches, amplifiers, integrators, comparators, flip-flops, AND/OR gates, and the like) to perform control functionality instead of relying upon software.

Controller 104 may include, or be associated with, one or more memory elements or non-transitory computer-readable storage mediums, such as RAM, ROM, EEPROM, EPROM, flash memory devices, magnetic disks, or other suitable memory devices (including combinations thereof). These memory devices may be a separate component from the processor or may be included onboard within the processor. In addition, these memory devices can store information and/or data accessible by the one or more processors, including instructions that can be executed by the one or more processors. It should be appreciated that the instructions can be software written in any suitable programming language or can be implemented in hardware. Additionally, or alternatively, the instructions can be executed logically and/or virtually using separate threads on one or more processors.

Referring again to FIG. 1, in some example embodiments, controller 104 may include one or more user input device 112, such as one or more of a variety of digital, analog, electrical, mechanical, or electro-mechanical input devices including rotary dials, control knobs, push buttons, toggle switches, selector switches, and touch pads. Additionally, controller 104 may include a display 114, such as a digital or analog display device generally configured to provide visual feedback regarding the operation of water heater appliance 100. According to the present example embodiment, user input device 112 and display 114 may be integrated into the controller 104, e.g., including one or more of a touchscreen interface, a capacitive touch panel, a liquid crystal display (LCD), a plasma display panel (PDP), or other informational or interactive displays.

Referring again to FIG. 2, in general, water heater appliance 100 may include a first temperature sensor 214 mounted to a front surface 215 of the heat exchanger 200. In particular, first temperature sensor 214 may record a first temperature. For example, the first temperature may be the temperature of the front surface 215 of the heat exchanger 200. In general, water heater appliance 100 may a second temperature sensor 216 mounted to an elbow 217 extending from heat exchanger 200. Particularly, second temperature sensor 216 may record a second temperature. For example, the second temperature may be the temperature of the elbow 217 extending from the heat exchanger.

As used herein, “temperature sensor” or the equivalent is intended to refer to any suitable type of temperature measuring system or device positioned at any suitable location for measuring the desired temperature. Thus, for example, temperature sensor 308 may be any suitable type of temperature sensor, such as a thermistor, a thermocouple, a resistance temperature detector, etc., or combinations thereof. In addition, temperature sensor 308 may be positioned at any suitable location and may output a signal, such as a voltage, to controller 104 that is proportional to and/or indicative of the temperature being measured. Although example positioning of temperature sensors is described herein, it should be appreciated that water heater appliance 100 may include any other suitable number, type, and position of temperature, humidity, and/or other sensors according to alternative example embodiments.

In general, controller 104 may be configured to operate in a scale detection mode. In the beginning of the scale detection mode, controller 104 may detect a type of water flowing through water line 210, e.g., the type of water may be hard water, natural (soft) water, or treated, softened water. For example, the detection of the type of water flowing through water line 210 may include receiving a user input of the type of water. Furthermore, in the scale detection mode, controller 104 may be configured to monitor the first temperature of the front surface 215 of the heat exchanger 200 with the first temperature sensor 214 while the water heater appliance is running. Also, controller 104 may monitor the second temperature, of the elbow 217, with the second temperature sensor 216 when the water heater appliance stops running. In general, controller 104 may be configured to record and store the first and second temperatures on a memory of the controller 104. Generally, the controller 104 may then calculate a difference between the first temperature and the second temperature, and determine scale buildup in the heat exchanger 200 based on the calculated difference between the first temperature and the second temperature, as will be further explained below.

In general, controller 104 may receive a command via a user input, such as manipulation of user input device 112, where activating the scale detection mode occurs in response to receiving the command via the user input. In other words, when activating a scale detection mode of the water heater appliance, the steps of monitoring, calculating and determining, as described above, are performed in response to activating the scale detection mode.

In general, before an initial installation of the water heater appliance 100, controller 104 may be configured to conduct a reliability test. The reliability test may include running the water heater appliance 100, without softener in the water, and stopping the water heater appliance 100 when overheating failure occurs. The controller 104 may record an initial first temperature of the front surface 215 of the heat exchanger 200 while the water heater appliance 100 is running during the reliability test, and an initial second temperature of the elbow 217 after ending the reliability test and the water heater appliance 100 stops running. In general, the initial first temperature is the maximum temperature of the front surface 215 of the heat exchanger 200 during operation of the water heater appliance 100, and the initial second temperature is the maximum temperature of the elbow 217, after the operation of the water heater appliance 100 has stopped. In other words, the recording of the initial first temperature and the initial second temperature may serve as preset values for the scale detection mode when the water heater appliance 100 is installed.

After first installation of the water heater appliance 100, in the scale detection mode, when the first temperature of the front surface 215 of the heat exchanger 200 exceeds the initial first temperature during operation of the water heater appliance 100, controller 104 may update the initial second temperature to the second temperature at that time. Similarly, when the second temperature of the elbow 217 exceeds the initial second temperature after the water heater appliance 100 stops running, controller 104 may update the initial first temperature to the first temperature at that time. In both cases described above, the user may be notified about the scale detection in the water heater appliance 100, e.g., the user may be notified by a warning light or audible tone.

Referring now to FIGS. 3 and 4, flow diagrams of example embodiments of methods 300, 400 of operating a water heater appliance are illustrated in accordance with aspects of the present subject matter. In general, methods 300, 400 will be described herein with reference to the embodiments of water heater appliance 100 described above with reference to FIGS. 1-2. However, it should be appreciated by those of ordinary skill in the art that the disclosed methods 300, 400 may generally be utilized in association with apparatuses and systems having any other suitable configuration. In addition, although FIGS. 3 and 4 depict steps performed in a particular order for purposes of illustration and discussion, the methods discussed herein are not limited to any particular order or arrangement. One skilled in the art, using the disclosures provided herein, will appreciate that various steps of the methods disclosed herein can be omitted, rearranged, combined, and/or adapted in various ways without deviating from the scope of the present disclosure.

As shown in FIG. 3, at (310), method 300 may generally include monitoring a first temperature of the front surface of the heat exchanger with the first temperature sensor while the water heater appliance is running. At (320), method 300 may generally include monitoring a second temperature of the elbow with the second temperature sensor when the water heater appliance stops running. Further, at (330), method 300 may generally include calculating a difference between the first temperature and the second temperature. Particularly, the temperature difference may be calculated by subtracting the second temperature form the first temperature, or, in other words, subtracting the temperature of elbow 217 from the temperature of the front surface 215 of heat exchanger 200. Moreover, at (340), method 300 may generally include determining scale buildup in the heat exchanger based on the difference between the first temperature and the second temperature. In general, the scale buildup occurs inside straight pipes of heat exchanger 200, e.g., proximate front surface 215, while the elbow 217 does not build up scale as frequently. For example, as the scale buildup in the heat exchanger 200 increases, the heat conductivity of heat exchanger 200 will be reduced and the temp on the front surface 215 of heat exchanger 200 will be increased, therefor the monitoring of the heat exchanger 200 temperatures may determine the level of scale deposits.

Referring now to FIG. 4, as shown at (410), method 400 may generally include activating a scale detection mode. For example, controller 104 may receive a command via a user input, such as manipulation of user input device 112, where activating the scale detection mode occurs in response to receiving the command via the user input. At (420), method 400 may generally include identifying a type of water. For example, controller 104 may identify a type of water flowing through water line 210, e.g., the type of water may be hard water, natural (soft) water, or treated, softened water. The identification of the type of water flowing through water line 210 may include receiving a user input of the type of water. When treated water is identified at (420), method 400 may generally include, (at 430), identifying a temperature differential between a first and second temperature. For example, the temperature differential may indicate overheating is occurring. When overheating is not indicated by the temperature differential, the scale detection mode may deactivate, however, when overheating is indicated, or when non-treated water is identified at (420), method 400 may generally include, at (440), identifying if it is the first installation of the water heater appliance. When it is not the first installation of the water heater appliance, then at (450), method 400 may generally include controller 104 comparing the temperature differential with the existing first and second temperatures. The existing first and second temperatures may have been stored on the memory elements of controller 104 from prior installations of the water heater appliance 100.

When it is the first installation of the water heater appliance, then at (460), method 400 may generally include controller 104 may compare the temperature differential with a preset first and second temperature. The preset first and second temperature may be the initial first temperature and the initial second temperature as described above with respect to the reliability test performed before first installation. When the first temperature of the heat exchanger exceeds the preset first temperature during operation of the water heater appliance 100, at (470), method 400 may generally include controller 104 updating the preset second temperature to the second temperature at that time. When the second temperature exceeds the preset second temperature after the water heater appliance 100 stops running, at (480), method 400 may generally include controller 104 updating the preset first temperature to the first temperature at that time. In both cases described above, at (490), method 400 may generally include providing a user notification to the user about the scale detection in the water heater appliance 100, e.g., the user may be notified by a warning light or audible tone.

As may be seen from the above, a method of detecting scale deposition in a tankless water heater may include temperature monitoring logic that may be set up based on the temperature sensors, with one at the heat exchanger's front surface and another at the heat exchanger's elbow pipe. The monitoring logic may be set up to determine the deposition of the scale and to avoid quality failure. Two values, a first temperature and a second temperature, may be set up for temperature monitoring logic, where the first temperature is the maximum temperature on the front surface of the heat exchanger, and the second temperature is the maximum temperature on the heat exchanger's elbow after stopping the operation of the water heater appliance. The two values, the first temperature and a second temperature, may be monitored continuously in the scale detection mode, and when any one of the values exceeds the prior set limit, failure occurs, and the user is notified about the scale deposit issue. The scale detection method may improve the quality and lifetime of the water heater without any additional cost.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

1. A method of operating a water heater appliance, the water heater appliance comprising a heat exchanger, a first temperature sensor disposed on a front surface of the heat exchanger, a second temperature sensor disposed on an elbow extending from the heat exchanger, and a controller, the method comprising: monitoring a first temperature of the front surface of the heat exchanger with the first temperature sensor while the water heater appliance is running;monitoring a second temperature of the elbow with the second temperature sensor when the water heater appliance stops running;calculating a difference between the first temperature and the second temperature; anddetermining scale buildup in the heat exchanger based on the difference between the first temperature and the second temperature.

2. The method of claim 1, further comprising, before an initial installation of the water heater, conducting a reliability test.

3. The method of claim 2, further comprising recording an initial first temperature of the front surface of the heat exchanger while the water heater appliance is running during the reliability test and an initial second temperature of the elbow after ending the reliability test and the water heater appliance stops running.

4. The method of claim 3, further comprising, when the first temperature of the front surface of the heat exchanger exceeds the initial first temperature during operation of the water heater appliance, updating the initial second temperature to the second temperature.

5. The method of claim 3, further comprising, when the second temperature of the elbow exceeds the initial second temperature after the water heater appliance stops running, updating the initial first temperature to the first temperature.

6. The method of claim 1, further comprising activating a scale detection mode of the water heater appliance, wherein the scale detection mode comprises the steps of monitoring, calculating and determining, and wherein the steps of monitoring, calculating and determining are performed in response to activating the scale detection mode.

7. The method of claim 6, further comprising receiving a command via a user input, wherein activating the scale detection mode occurs in response to receiving the command via the user input.

8. The method of claim 1, further comprising detecting a type of water flowing through a water line.

9. The method of claim 8, wherein detecting the type of water comprises detecting one of hard water or softened water.

10. The method of claim 8, wherein detecting the type of water flowing through the water line includes receiving a user input, the user input comprising the type of water.

11. A water heater appliance comprising: a heat exchanger a first temperature sensor disposed on a front surface of the heat exchanger;a second temperature sensor disposed on an elbow extending from the heat exchanger; anda controller, the controller configured to: monitor a first temperature of the front surface of the heat exchanger with the first temperature sensor while the water heater appliance is running;monitor a second temperature of the elbow with the second temperature sensor when the water heater appliance stops running;calculate a difference between the first temperature and the second temperature; anddetermine scale buildup in the heat exchanger based on the difference between the first temperature and the second temperature.

12. The water heater appliance of claim 11, wherein the controller is further configured to, before an initial installation of the water heater, conduct a reliability test.

13. The water heater appliance of claim 12, wherein the controller is further configured to record an initial first temperature of the front surface of the heat exchanger while the water heater appliance is running during the reliability test and an initial second temperature of the elbow after ending the reliability test and the water heater appliance stops running.

14. The water heater appliance of claim 13, wherein the controller is further configured to, when the first temperature of the front surface of the heat exchanger exceeds the initial first temperature during operation of the water heater appliance, updating the initial second temperature to the second temperature.

15. The water heater appliance of claim 13, wherein the controller is further configured to, when the second temperature of the elbow exceeds the initial second temperature after the water heater appliance stops running, updating the initial first temperature to the first temperature.

16. The water heater appliance of claim 11, further comprising activating a scale detection mode of the water heater appliance, wherein the scale detection mode comprises the steps of monitoring, calculating and determining, and wherein the steps of monitoring, calculating and determining are performed in response to activating the scale detection mode.

17. The water heater appliance of claim 16, further comprising receiving a command via a user input, wherein activating the scale detection mode occurs in response to receiving the command via the user input.

18. The water heater appliance of claim 11, further comprising detecting a type of water flowing through a water line.

19. The water heater appliance of claim 18, wherein detecting the type of water comprises detecting one of hard water or softened water.

20. The water heater appliance of claim 18, wherein detecting the type of water flowing through the water line includes receiving a user input, the user input comprising the type of water.