US20250297773A1

US20250297773A1 - Heating assembly with recirculation loop for storage of heated liquid

Info

Publication number: US20250297773A1
Application number: US19/088,283
Authority: US
Inventors: Gregory S. Lyon
Original assignee: Ohmiq Inc
Current assignee: Ohmiq Inc
Priority date: 2024-03-22
Filing date: 2025-03-24
Publication date: 2025-09-25
Also published as: WO2025199529A1

Abstract

A heater assembly includes a housing that defines a reservoir, and an electric heater for heating a conductive fluid within the reservoir. The electric heater includes selectable electrodes, arrayed in such a way as to form channels that define a first fluidic path of a fluidic circuit within the reservoir of the heater assembly. The housing supports baffles that form a plurality of channels that define a second fluidic path within the reservoir that communicates with the first fluidic path to form the fluidic circuit. A recirculation pump is provided to pump the fluid through the fluidic circuit in a continuous loop to uniformly heat the fluid within the reservoir.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the filing date of provisional U.S. Patent Application No. 63/568,740 filed on Mar. 22, 2024.

FIELD

This disclosure is directed to electric water heaters, and more particularly to electric Point-Of-Use (“POU”) water heaters.

BACKGROUND

Water heaters intended for POU are known and are becoming more popular and pervasive. In particular, the ability to provide heated water across a wide temperature range is beneficial as it may obviate the need for a post-pour heater, such as a kettle, etc. In fact, POU water heaters can produce temperatures of water up to 100° C. Water temperatures in this range are conducive to the preparation of hot beverages, such as coffee or tea, directly from the faucet.
These POU water heaters can be found in top-end kitchens. They are typically installed beneath the sink, so they need to be relatively small. The use of electricity is prevalent as the heating energy. Since the electrical energy available in this location is limited, the heater operates in a storage mode. That is, there is a relatively long heating up period, after which hot water may be drawn at normal flow rates, to the extent of the volume of heated water already stored at the time of the pour.
FIG. 1 illustrates a conventional water heater 10 that includes a vessel 12 defining a volume into which a resistive heating element 14 is submerged. Representative examples of this can be found in the series of boiling water taps sold by Quooker UK LTD under the trademark QUOOKER®. The top of the water heater 10 is provided with an upper flange 16 that is mounted to the upper end of the vessel 12, and a lower flange 18 that is mounted to the lower end of the vessel 12. The upper flange 16 and the lower flange 18 seal components of the water heater 10 to the vessel 12. The resistive heating element 14 extends from the upper flange 16 into the vessel 12 and includes a lower end that has a helical portion 20 that provides the majority of heating of the water within the vessel 12.
The operation of the water heater 10 is relatively simple. It consists of filling the volume of the vessel 12 with cold water through a water inlet tube 22, then applying heat via the resistive heating element 14 to heat the water to some thermal setpoint. When a discharge valve of the faucet (not shown) is opened for a pour, cold water from a water main connected to the vessel 12 pushes the hot water within the vessel 12 through the faucet.
The helical portion 20 of the resistive heating element 14 is located at the bottom of the vessel 12, ostensibly to effect some convective/buoyancy mixing of the water in the vessel 12. As the water in contact with the outer surface of the resistive heating element 14 heats up, the local density of the heated water decreases, and the heated water tends to rise within the vessel 12.
This type of heating water is random in nature. The buoyancy forces the heated water into indeterminate, unpredictable paths from the lower end of the vessel 12 towards the upper end of the vessel 12. The temperature within the vessel 12 is therefor inconsistent. Provisions are made to selectively tap the hot water, but the thermal randomness of the volume precludes a consistent temperature during a pour from the faucet. The exclusive use of buoyancy forces for mixing hot water and cold water also constrains the operation of the water heater 10 to a vertical orientation.
Further, during the pour, cold water from the supply main is entrained into the vessel 12. Since mixing is inevitable, some cold water is delivered to the faucet along with the hot water. This adds further inconsistency to the pour temperature.
Finally, the static nature of the water in the vessel 12 is conducive to overheating at the surface of the resistive heating element 14, accelerating scaling and degradation of the resistive heating element 14. Eventually the resistive heating element 14 will burn out because the resistive heating element 14 will not be able to conduct enough heat through the scaling.
Accordingly, further improvement in this area would be desired, including providing a POU water heater that has a more consistent water pour temperature.

SUMMARY

Aspects of the disclosure are directed to a heater assembly for the heating a conductive liquid. The heater assembly includes a structure to define a circuitous fluidic circuit including a secures of baffles that define a first fluidic path of the fluidic circuit and an array of electrodes defining a second fluidic path of the fluidic circuit. The heater assembly includes a recirculating pump to continuously pump the liquid through the fluidic circuit during a heating stage of the heater assembly. The heater assembly also includes a fluid inlet and a fluid outlet to receive and discharge liquid from the heater assembly.
A further aspect of the disclosure provides for sufficient fluidic flow to result in a determinate, coherent flow to accommodate the heating within the electrode array. Such flow has sufficient ‘wash’ so that the thermal profile across the electrodes is essentially constant.
Aspects of the disclosure are directed to a system for heating water including a heater assembly, a recirculation pump, and a controller. The heater assembly includes an electric heater, a housing defining a water reservoir, and a continuous fluidic circuit defined within the water reservoir. The continuous fluidic circuit includes a first fluidic path and a second fluidic path. The first fluidic path has an inlet. The second fluidic path communicates with the first fluidic path and has an inlet, an outlet, and a circuitous configuration. The electric heater is positioned to heat water passing along the second fluidic path within the fluidic circuit. The recirculation pump is coupled to the fluidic circuit and operable to recirculate the water through the fluidic circuit. The controller is operable to actuate the electric heater to supply heat to the water passing through the second fluidic path of the fluidic circuit.
In aspects of the disclosure, the circuitous configuration of the first fluidic path is a serpentine configuration.
In some aspects of the disclosure, the circuitous configuration of the second fluidic path is a serpentine configuration.
In certain aspects of the disclosure, the electric heater is an ohmic heater and includes two or more electrodes that define a portion of the second fluidic path.
In aspects of the disclosure, the housing includes a sleeve that defines a cavity, and further including a heater support received within the cavity.
In some aspects of the disclosure, the electric heater is supported within the heater support.
In certain aspects of the disclosure, the heater support includes baffles that define the first fluidic path.
In aspects of the disclosure, the first fluidic path encircles the second fluidic path, and the electric heater is centrally located with the water reservoir.
In some aspects of the disclosure, the inlet of the second fluidic path is connected to the outlet of the first fluidic path, and the outlet of the second fluidic path is connected to the recirculation pump and to a faucet.
In certain aspects of the disclosure, the inlet of the first fluidic path is adapted to be coupled to a water source.
In aspects of the disclosure, the housing includes a sleeve having a first end and a second end, a first pressure plate secured to the first end of the sleeve, a second pressure plate secured to the second end of the sleeve, a power cap secured to the first end of the sleeve, and an end cap secured to the second end of the sleeve.
In some aspects of the disclosure, the power cap and the end cap define portions of the first fluidic path and the second fluidic path.
In certain aspects of the disclosure, the heater assembly includes a temperature sensor, and the controller is electrically coupled to the heater, the temperature sensor, and the recirculation pump and is operable to maintain the fluid at a setpoint temperature.
In aspects of the disclosure, the second fluidic path includes channels, and the aspect ratios of each of the channels defining the second fluidic path is greater than 1.
In some aspects of the disclosure, the channels of the second fluidic path are configured such that the water flow through the second fluidic path has a Reynolds number of greater than 4000.
Other aspects of the disclosure are directed to a heater assembly including a housing defining a reservoir, a fluidic circuit, and an electric heater. The fluidic circuit is defined within the reservoir and has a first fluidic path and a second fluidic path. The first fluidic path has an inlet, and an outlet. The second fluidic path communicates with the first fluidic path and has an inlet, an outlet, and a circuitous configuration. The first fluidic path is connected to the second fluidic path to facilitate recirculation of fluid through the fluidic circuit. The electric heater is positioned to heat water passing along the second fluidic path. The inlet of the first fluidic path is adapted to be coupled to a water source and the outlet of the second fluid path is adapted to be connected to a faucet.
In aspects of the disclosure, the second fluidic path includes channels having an aspect ratio greater than 1 and is configured such that water flow through the second fluidic path has a Reynolds number greater than 4000.
In some aspects of the disclosure, the circuitous configuration of the second fluidic path is a serpentine configuration.
In certain aspects of the disclosure, the electric heater is an ohmic heater and includes two or more electrodes that define a portion of the second fluidic path.
In aspects of the disclosure, the housing includes a sleeve that defines a cavity, and the heater assembly includes a heater support that is received within the cavity
In some aspects of the disclosure, the electric heater is supported within the heater support.
In certain aspects of the disclosure, the heater support includes baffles that define the first fluidic path.
In aspects of the disclosure, the first fluidic path encircles the second fluidic path, and the electric heater is centrally located with the reservoir.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of the disclosed heater assembly and heater system are described herein below with reference to the drawings, wherein:

FIG. 1 is a side perspective view of a Prior Art POU water heater;

FIG. 2 is a side perspective view of a heater assembly according to aspects of the disclosure;

FIG. 3 is a side perspective, partially exploded view of the heater assembly of FIG. 2 ;

FIG. 4 is a perspective view from above of an electrode support of the heater assembly of FIG. 2 ;

FIG. 5 is a cross-sectional view of the heater assembly of FIG. 2 taken along section line 5-5 of FIG. 2 illustrating the flow of water through the electrode support of the heater assembly;

FIG. 6 is a cross-sectional view of the heater assembly taken along section line 6-6 of FIG. 2 illustrating the flow of water from the electrode support into the electric heater of the heater assembly;

FIG. 6A is a cross-sectional view of the heater assembly of FIG. 2 taken along section line 6A-6A illustrating the flow of water through the electric heater of the heater assembly;

FIG. 7 is a schematic view of a hydraulic circuit of the heater assembly system including the heater assembly shown in FIG. 1 according to aspects of the disclosure;

FIG. 8 is a side perspective view of an alternative version of a heater assembly according to aspects of the disclosure;

FIG. 9 is an exploded view of the heater assembly shown in FIG. 8 ;

FIG. 10 is a side perspective view of the heater assembly shown in FIG. 8 with the sleeve shown in phantom and the heater support removed;

FIG. 11 is an enlarged view of the indicated area of detail shown in FIG. 10 ;

FIG. 12 is a cross-sectional view taken along section line 12-12 of FIG. 8 ;

FIG. 13 is a cross-sectional view taken along section line 13-13 of FIG. 8 ;

FIG. 14 is a cross-sectional view taken along section line 14-14 of FIG. 8 ;

FIG. 15 is a side perspective view of the heater support of the heater assembly shown in FIG. 8 ;

FIG. 16 is a cross-sectional view taken along section line 16-16 of FIG. 15 ; and

FIG. 17 is a cross-sectional view taken along section line 17-17 of FIG. 9 .

DETAILED DESCRIPTION

Although illustrative systems of this disclosure will be described in terms of specific aspects, it will be readily apparent to those skilled in this art that various modifications, rearrangements, and substitutions may be made without departing from the spirit of this disclosure.
For purposes of promoting an understanding of the principles of this disclosure, reference will now be made to exemplary aspects illustrated in the figures, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of this disclosure is thereby intended. Any alterations and further modifications of this disclosure features illustrated herein, and any additional applications of the principles of this disclosure as illustrated herein, which would occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the scope of this disclosure.
As used herein, a POU water heater is a compact heating device installed directly at the location where hot water is needed that allows for instantaneous hot water delivery.
FIGS. 2 and 3 illustrate a heater assembly 100 in accordance with aspects of the disclosure. The heater assembly 100 includes a printed circuit board assembly (PCBA) 110, electrodes 112 (FIG. 3 ), a first pressure plate 114, a second pressure plate 116, a power cap 118, an end cap 120, and a sleeve 122. The first pressure plate 114 supports the PCBA 110 and defines a fluid inlet 123 for introducing fluid, e.g., water, into the heater assembly 100. In aspects of the disclosure, the fluid inlet 123 is adapted to be connected to a fluid supply, e.g., a water main. The sleeve 122 defines a cavity 122 a (FIG. 5 ) and is configured to resist hoop stresses due to hydraulic pressure within the heater assembly 100. The sleeve 122 may have a cylindrical configuration although other configurations are envisioned. The sleeve 122 may include a first flange 124 positioned at the first end of the sleeve 122 and a second flange 126 positioned at the second end of the sleeve 122. The first and second flanges 124 and 126 facilitate securement of the sleeve 122 to the first and second pressure plates 114 and 116, the power cap 118, and the end cap 120. The power cap 118 is clamped between the first pressure plate 114 and the first flange 124, and the end cap 120 is clamped between the second pressure plate 116 and the second flange 126. In aspects of the disclosure, screws 128 are used to secure the power cap 118 and the first pressure plate 114 to the first flange 124 and to secure the end cap 120 and the second pressure plate 116 to the second flange 126 although other securement devices and techniques are envisioned. The first and second pressure plates 114 and 116 resist axial reaction loads from hydraulic pressure within the sleeve 122. In aspects of the disclosure, the power cap 118 and the end cap 120 are configured to define a portion of a fluidic circuit “C” (FIG. 7 ) defined within the heater assembly 100 as described in further detail below. In some aspects of the disclosure, the power cap 118 includes structure to support the electrodes 112 such that the electrodes 112 extend from the power cap 118 through the sleeve 122 towards the end cap 120. The pressure plates 114 and 116, the power cap 118, the end cap 120, and the sleeve 122, when secured together, define form a housing that defines a reservoir 127.
In some aspects of the disclosure, the sleeve 122 may include or support mounting brackets 124 a and 126 a that are configured to support the heater assembly 100 to an adjacent structure. In certain aspects of the disclosure, the mounting brackets 124 a and 124 b are formed integrally with the first and second flanges 124 and 126. Alternately, the mounting brackets 124 a and 124 b may be formed independently of the flanges 124 and 126.
FIG. 4 illustrates a heater support 131 that is received within the sleeve 122 (FIG. 3 ) and may have a configuration that corresponds to the configuration of the cavity 122 a defined by the sleeve 122. Although the configuration of the cavity 122 a is shown to be cylindrical, other configurations are envisioned. The heater support 131 includes an outer wall 132, internal baffles 133 that extend from the outer wall 132 into the cavity 122 a of the sleeve 122, and a carrier 134. In aspects of the disclosure, the carrier 134 is centrally located within the outer wall 132 of the heater support 131 although other configurations in which the heater support 131 is not centered within the heater support 131 or within the reservoir 127 are envisioned. In some aspects of the disclosure, the carrier 134 defines external channels 136 that extend from the first end of the carrier 134 to a second end of the carrier 134 and receive ends of the internal baffles 133 to support the carrier 134 within the sleeve 122. Alternatively, it is envisioned that components of the heater support 131 including the outer wall 132, the internal baffles 133, and the heater support 131 may be integrally formed. The baffles 133, the power cap 118, and the end cap 120 are configured to define a first fluidic path “A” that is circuitous (FIG. 5 ). In some aspects of the disclosure, the first fluidic path “A” extends around or encircles the carrier 134 as described in further detail below. In some aspects of the disclosure, the first fluidic path “A” has a serpentine configuration although other circuitous configurations are envisioned.
The carrier 134 is illustrated as having a rectangular configuration and includes internal walls 140. In aspects of the disclosure, the internal walls 140 define longitudinal channels 142 that receive and support the electrodes 112 within the carrier 134 in spaced relationship to each other. Alternatively, it is envisioned that the electrodes 112 can be supported within the carrier 134 in a variety of manners. The electrodes 112 are spaced from each other to form channels that define a second fluidic path “B” (FIG. 6A) through the carrier 134 that is circuitous. In some aspects of the disclosure, the second fluidic path “B” may have a serpentine configuration although other configurations are envisioned. In aspects of the disclosure the first circuitous path “A” and the second circuitous path “B” define the fluidic circuit “C” within the heater assembly 100. It is envisioned that the carrier 134 can have a variety of different configurations.
The heater support 131 provides electrical isolation, and in that regard is desirably constructed from a dielectric or electrically-insulative material. The carrier 134 provides structural support for the electrodes 112 to position the electrodes 112 in an array for supplying electricity to the fluid, e.g. water, to thereby heat the water.
In some aspects of the disclosure, the heater assembly 100 includes a PCBA 110 as depicted in FIG. 2 . The PCBA 110 is configured to receive electrical power and control signals and to distribute power to the electrodes 112. In certain aspects of the disclosure, rather than receiving control signals, the PCBA 110 can include components that provide control functionality to provide power to the electrodes 112 to operate the heater assembly 100. The PCBA 110 may include various electrical components, such as power management circuitry, sensing circuitry, relay or switching circuitry, one more controller(s), one or more memory, and/or communication circuitry, among other possible components.
In aspects of the disclosure, the PCBA 110 may include power management circuitry which manages voltage and/or current, such as AC/DC converters, step-up converters, step-down converters, and/or waveform shaping circuitry (e.g., pulse width modulation circuitry), among other possibilities.
In aspects of the disclosure, the PCBA 110 may include sensing circuitry such as voltage sensors, current sensors, and/or circuitry that interfaces with sensors in the heater, such as circuitry that interfaces with temperature sensors in the heater, for example. The sensing circuitry may include, for example, amplifiers and/or analog-to-digital converters, among other possibilities.
In aspects of the disclosure, the PCBA 110 may include relay or switching circuitry such as switches that connect and disconnect power to various electrodes 112 in the array of electrodes 112. The relay or switching circuitry may include switches that connect to different electrical potentials from a power source, or solid-state switches, among other possibilities.
In aspects of the disclosure, the PCBA 110 may include one or more controller(s), which may include any type of device that can provide control and/or computing functionality, such as microcontrollers, microprocessors, central processing units, and/or digital signal processors, among other possibilities. In some aspects of the disclosure, the controller(s) may include and may execute firmware instructions. In certain aspects of the disclosure, the controller(s) may execute machine-readable instructions accessed from the one or more memories, which may include volatile memory (e.g., random access memory, etc.) and/or non-volatile memory (e.g., EEPROM, etc.). The machine-readable instructions may implement control functionality, such as controlling operations of the heater assembly 100. In aspects of the disclosure, the control functionality may connect power to various electrodes 112 of the array of electrodes at various times according to a predetermined operation. The control functionality may also process sensing signals provided by the sensing circuitry to perform various computations and may connect power to various electrodes 112 of the array of electrodes based on the computations. For example, the one or more controller(s) may operate to direct power to various electrodes 112 of the array of electrodes in different cycles. As another example, the controller(s) may receive an input reflective of a set point temperature and receive sensing signals reflective of measured temperatures in the heater assembly 100. The controller may direct or not direct power to various electrodes 112 of the array of electrodes 112 based on the set point temperature and the sensing signals reflective of the measured temperatures. Various other operations are described below herein. All such operations are contemplated to be within the scope of the present disclosure.
In aspects of the disclosure, the PCBA 110 may include communication circuitry, such as wireless communication circuitry enabling communication using technologies such as Wi-Fi, Bluetooth, and/or cellular communications, among other wireless communication technologies. In some aspects of the disclosure, the communication circuitry may communicate with a user device, such as a smartphone, tablet, or other user device. In certain aspects of the disclosure, the communication circuitry may transmit information to and/or receive information from a cloud system. The information communicated by the communication circuitry may be used in various ways, such as used by a user app to control operation of the heater and/or to view performance of the heater, or use to update firmware within the heater, among other possibilities. Such and other embodiments are contemplated to be within the scope of the present disclosure.
In aspects of the disclosure, the electrodes 112 function as part of an ohmic heater 150 (FIG. 6A) that operates by directing electric current through the water flowing through the second fluidic path “B” defined by the carrier 134 and the electrodes 112 so that the water is heated by conversion of electrical energy to heat within the water itself. In that regard, the electrodes 112 function as locations where the electrical current passes into the water from conductors, i.e., the electrodes 112, electrically coupled with poles of a power source. The electrodes 112 may be arranged so that different electrodes 112 can be selectively connected to opposing poles of the power source to define different current paths through the water. Precise control of the electrical energy applied to the water, and thus the amount of heating applied to the water, can be realized by selecting different combinations of electrodes 112 (spaced at different distances from one another) to connect to respective poles of the power source. The selective connection of the electrodes 112 to the power supply may occur during a succession of actuation intervals, which may be repeatedly cycled during operation of the heater. The arrangement of the electrodes 112 and the control of the power applied to them is not particularly limited here, and any of the arrangements and control schemes can be utilized that are disclosed in U.S. Pat. No. 7,817,906 (“the '906 Patent”), U.S. Pat. Nos. 8,861,943, 11,353,241 (“the '241 Patent”), U.S. Pat. No. 10,365,013 (“the '013 Patent”), U.S. Pat. Appl. Pub. No. 2022/0268140, and U.S. Pat. Appl. Pub. No. 2021/0153302, the entire contents of each of which are incorporated herein by reference. For example, switches like those disclosed in the '906 Patent may be used for selectively activating and deactivating various electrodes 112 of the array of electrodes 112. Moreover, at least some of the electrodes 112 may also be electrically connected to shunting switches as described in the '241 Patent to create more connection schemes for even more precise control. Even further, a controller may operate by a control scheme that includes modeling the fluid passing through the spaces between the electrodes 112 as a series of finite elements, as disclosed in the '013 Patent.
FIGS. 5 and 6 illustrate a partial sectional view of the heater assembly 100 as water travels through the first fluidic path “A” defined by the baffles 133 of the heater support 131, the power cap 118, and the end cap 120. In aspects of the disclosure, the first fluidic path “A” communicates with the inlet opening 123 defined by the first pressure plate 114 to receive cold water. The baffles 133 define channels between adjacent baffles 133. In some aspects of the disclosure, the upper ends and lower ends of each of the baffles 133 engage baffles 133 a formed in the power cap 118 and end cap 120 in alternating fashion to define the first fluidic path “A”. The first fluidic path “A” may be configured so that the fluid flows within the sleeve 122 of the heater assembly 100 by alternately traversing back and forth in opposite directions between successive pairs of baffles 133. As illustrated in FIG. 4 , the first fluidic path “A” may have a serpentine configuration and may extend around the carrier 134. Alternatively, other path positions configurations are envisioned including paths that extend within or on opposite ends of the second fluidic path “B”.
FIG. 6A further illustrates a partial sectional view of the heater assembly 100 as water travels through the second fluidic path “B” defined by the carrier 134, the electrodes 112, the power cap 118, and the end cap 120. As illustrated, the first fluidic path “A” communicates with the second fluidic path “B” through an opening 160 defined by the power cap 118. Each of the adjacent electrodes 112 of the array of electrodes defines a channel through which the water flows. The baffles 133 a of the power cap 118 and the end cap 120 alternatingly engage upper and lower ends of the electrodes 112 to define the second fluidic path “B” through the Ohmic heater 150. One end of the second fluidic path “B” communicates with a fluid outlet 162 to allow water to exit the heater assembly 100 through the fluid outlet 162 to a faucet 168 or a recirculation pump 170 (FIG. 7 ) as described in further detail below.
In aspects of the disclosure, the aspect ratio (width/height) of the channels defined by the electrodes 112 in the second fluidic path “B” (where the width is the width of the electrodes 112 and the height is the spacing between the electrodes 112 in the channels) are greater than 1 to minimize stagnation within the channels defining the second fluidic path “B”. By minimizing stagnation, a uniform heating of the water within the fluidic circuit “C” is achieved. In addition, the channels within the second fluidic path “B” are configured to result in turbulent water flow through the second fluidic path “B” at the setpoint temperature. In some aspects of the disclosure, the water flow through the second fluidic path “B” has a Reynolds number of greater than 4000. The turbulent flow through the second fluidic path “B” also minimizes stagnation within the second fluidic path “B” to provide for more uniform heating of the water.
FIG. 7 illustrates a POU fluid heating system 169 including the heater assembly 100. In aspects of the disclosure, the fluid heating system 169 includes a recirculation pump 170 (FIG. 7 ) for recirculating water from the fluid outlet 162 (FIG. 6A) back to the fluid inlet 123. The fluid heating system 169 is adapted to be connected to a water source, e.g., a water main 180, and may include a first check valve 182, a second check valve 184, and a temperature sensor 186. Although the recirculation pump 170 is shown to be external to the heater assembly 100, it is envisioned that the recirculation pump 170 may be incorporated into the heater assembly 100 or supported on the housing of the heater assembly 100. The first check valve 182 is positioned between the water main 180 and the fluid inlet 123 and prevents backflow of fluid from the heater assembly 100 into the water main 180 and fluid flow from the water main 180 into the heater assembly 100 when the pressure within the heater assembly 100 exceeds the pressure in the water main 180. The second check valve 184 is positioned between the water main 180 and the recirculation pump 170 and prevents fluid flow from the water main 180 into an outlet of the recirculation pump 170. In aspects of the disclosure, the temperature sensor 186 is positioned between the fluid outlet 162 of the heater assembly 100 and the recirculation pump 170. It is envisioned that the fluid heating system 169 may have a variety of configurations that facilitate recirculation of a fluid through the heater assembly 100.
The operation of the heater assembly 100 will now be described with reference to FIG. 7 . After installation, the heater assembly 100 is filled with water and purged of any remaining air by opening the faucet 168. Once the heater assembly 100 is fully filled with water, the recirculation pump 170 is activated and water is allowed to circulate through the fluidic circuit “C” defined by the first fluidic path “A” and the second fluidic path “B”. If the faucet 168 is closed, the water continues to flow through the fluidic circuit “C”, driven by the recirculation pump 170, where the water passes the temperature sensor 186 and the second check valve 184 before reentering the heater assembly 100 and passing through the fluidic circuit “C” again. The check valve 184 prevents water from the water main 180 from flowing into the outlet of the recirculation pump 170 when the recirculation pump 170 is not operating.
When the ohmic heater 150 is activated, water is heated with each pass of water around the fluidic circuit “C”. Once the temperature of the water reaches the setpoint, the heater assembly 100 and the recirculation pump 170 may be turned off. At some frequency, the recirculation pump 170 may be turned on again, the water temperature measured, and additional heat added as required to maintain the water at the setpoint.
When a pour is required, the faucet 168 is opened and the water flow is redirected from the recirculation pump 170 to the faucet 168. At that time, the recirculation pump 170 is turned off to avoid mixing hot and cold water. When the faucet 168 is opened, the pressure within the heater assembly 100 decreases allowing make-up water from the water main 180 to pass through the check valve 182 into the fluid inlet 123 of the heater assembly 100. Desirably, the make-up water (e.g., cold water from the main supply) pushes the hot water within the fluidic circuit “C” out to the faucet 168. Due to the arrangement described, with the water inlet 123 on an opposite side of the heater assembly 100 from the faucet 168 and the circuitous fluidic circuit “C” connecting the fluid inlet 123 to the fluid outlet 162, the hot water from the heater assembly 100 is almost entirely purged through the faucet 168 before cold water from the inlet mixes with the hot water to lower the outlet water temperature.
In some aspects of the disclosure, the cross-sectional area of the channels defined between the baffles 133 of the heater support 131 in the first fluidic path “A” is greater than the cross-sectional area of the channels defined between the electrodes 112 in the second fluidic path “B”. The difference between the cross-sectional areas in the first fluidic path “A” and the second fluidic path “B” results in fluid flowing through the first fluidic path “A” at a lower velocity than the water flowing through the second fluidic path “B”. The lower velocity within the first fluidic path “A” reduces convective heat transfer loss through the heater support 131.
It is an aspect of the disclosure that the volume defined between the baffles 133 and within the internal diameter of the heater support 131, constitutes the volume of the heating reservoir 127. Because the water is periodically or continuously recirculated, the water is not allowed to stagnate. Thus, the water tends to heat evenly and avoids the development of hot spots and/or cold spots.
It is a further aspect of this disclosure that the cold incoming water is not allowed to mix with the water exiting the heater assembly 100, so that the amount of dispensed hot water can be maximized before it is cooled by the incoming cold water.
It is a further aspect of this disclosure that the ohmic array is designed so that there is no stagnation within the fluidic circuit “C”. This is due to the aspect ratio of each channel.
It is a further aspect of this disclosure that the flow throughout the ohmic heater 150 is primarily turbulent or near-turbulent, which desirably further reduces the possibility of stagnation at the corners of the heating channels. That is, the velocity profile of turbulent flow is more uniform than laminar flow, and thus the boundary layers tend to be thinner.
It is a further aspect of this disclosure that the cross-sectional areas of the fluidic circuit defined by the baffles 133 in the electrode support significantly reduce the fluid velocity, thus reducing the convective heat transfer loss through the outside diameter of the electrode support.
It is a further aspect of this disclosure that the flow rate [is flow rate correct here or is it flow?] through the ohmic heater is sufficient to treat it as isothermal, which greatly simplifies modeling and the controls.
FIGS. 8-17 illustrate a heater assembly according to further aspects of the disclosure shown generally as heater assembly 200. The heater assembly 200 includes a printed circuit board assembly (PCBA) 210, electrodes 212 (FIG. 9 ), a first pressure plate 214, a second pressure plate 216, a power cap 218, an end cap 220, and a sleeve 222. The first pressure plate 214 supports the PCBA 210 and includes a first fitting 224 that defines a fluid inlet for introducing fluid, e.g., water, into the heater assembly 200 and a second fitting 226 that defines a fluid outlet adapted to be coupled to a fixture, e.g., a faucet. In aspects of the disclosure, the fitting 224 is adapted to be connected to a fluid supply, e.g., a water main. The sleeve 222 defines a cavity 222 a (FIG. 9 ) and is configured to resist hoop stresses due to hydraulic pressure within the heater assembly 200. In some aspects of the disclosure, the sleeve 222 has a cylindrical configuration although other configurations are envisioned. The sleeve 222 receives a heater support 230 (FIG. 9 ) and a liner 232 that is positioned about the heater support 230 to minimize convective heat transfer loss through the heater support 230. The heater support 230 and the liner 232 have shapes that correspond to the shape of the internal configuration of the sleeve 222. In some aspects of the disclosure, the heater support 230 and the liner 232 form a integral unit that can be slid into the sleeve 222 during manufacture.
The first pressure plate 214 and the power cap 218 are secured to one end of the sleeve 222, and the second pressure plate 216 and the end cap 220 are secured to an opposite end of the sleeve 222 to form a housing 236 of the heater assembly 200 that defines a reservoir 238 (FIG. 10 ). In aspects of the disclosure, the heater assembly 200 includes elongate bolts 240 (FIG. 14 ) that extend between the first pressure plate 214 and the second pressure plate 216 to secure the components to the sleeve 222. In some aspects of the disclosure, the heater assembly 200 includes four bolts 240 that are positioned within cylinders 242 that extend between the power cap 218 and the end cap 220. In aspects of the disclosure, the power cap 218 and the end cap 220 are configured to define a portion of a fluidic circuit “C” (FIG. 12 ) defined within the heater assembly 200 as described in further detail below. In some aspects of the disclosure, the power cap 218 includes structure 218 a (FIG. 17 ) to support the electrodes 212 such that the electrodes 212 extend from the power cap 218 through the sleeve 222 and the towards the end cap 120. In certain aspects of the disclosure, the power cap 218 defines slots 218 b that receive the electrodes 212 to support the electrodes 212 within the reservoir 238 (FIG. 10 ).
The PCBA 210 is secured to the first pressure plate 214 of the heater assembly 200 and is coupled to a power supply. The PCBA 210 may be electrically coupled to a switching device 244 which may include Triac's that are coupled to the electrodes 212 by conductors 248. The switching device 244 directs power selectively to various electrodes 212 in response to control inputs to control heating of the water flowing between the electrodes 212. In aspects of the disclosure, each of the conductors 248 has a first end that is secured to the PCBA 210 and a second end that defines a U-shaped portion 250 that is engaged with the one of the electrodes 212. In some aspects of the disclosure, the switching device 244 includes a cooling circuit 252 (FIG. 8 ) that receives fluid from the first fluidic path “D” (FIG. 12 ), delivers the fluid to a cooling passageway within the switching device 244 and returns the fluid to the first fluidic path “D”. It is envisioned that the cooling circuit 252 may be independent of the fluidic circuit defined within the housing 236.
In aspects of the disclosure, the second pressure plate 216 supports a recirculation pump 254 that has an inlet 256 (FIG. 13 ) that receives fluid from the outlet of the second fluidic path “E” (FIG. 13 ) defined by the electrodes 212 and an outlet (not shown) that communicates with the fluidic path “D” defined by the heater support 230. The recirculation pump 254 recirculates fluid through the fluidic circuit defined by the fluidic path “D” and the fluidic path “E” to heat the fluid within the reservoir 238. In some aspects of the disclosure, the heating assembly 200 includes sensors 260, 262 (temperature, pressure) to control fluid flow and temperature through the reservoir 238. The sensors 260, 262 communicate with the PCBA 210 to control activation of the recirculation pump 254 when recirculation through the electrodes 212 is indicated.
FIGS. 14-16 illustrate the heater support 230 which includes an upper baffle 270, a lower baffle 272, a semi-circular body 274, and a carrier 276. The carrier 276 receives the electrodes 212 to form an electric heater 280 (FIG. 14 ) within the heater support 230. In aspects of the disclosure, the carrier 276 includes grooves or slots 282 that receive and support the electrodes 212 within the carrier 276 at predetermined spacings to define the fluidic path “E” through the electric heater 280 (FIG. 13 ). In certain aspects of the disclosure, the upper baffle 270 and the lower baffle 272 each define annular recesses 284 and 286, respectively, that receive O-rings 288 and 290 (FIG. 12 ) that seal between the outer surface of the upper and lower baffles 270 and 272 and the inner surface of the liner 232. In aspects of the disclosure, the body 274 of the heater support 230 defines a first chamber 298, a second chamber 300, and a third chamber 302. The upper baffle 270 defines a fluid opening 304 into the first chamber 298, and the lower baffle 272 defines a fluid outlet 306 from the first chamber 298 into the second chamber 300. In some aspects of the disclosure, the lower surface of the lower baffle 272 defines a channel 308 (FIG. 12 ) that connects the first chamber 298 with the second chamber 300. The upper baffle 270 includes an outlet opening 310 that allows fluid to flow from the second chamber 300 through an opening 312 in the upper baffle 270 into the third chamber 302, and the third chamber 302 is connected to the second fluidic path “E” through the electric heater 280. In aspects of the disclosure, the first fluidic path “D” defined by the heater support 230 and the electrodes 212 of the fluidic heater 230 are circuitous and may have a serpentine configuration.
As described above regarding the heater assembly 100, the second fluidic path “E” is defined by channels formed between adjacent electrodes 212 of the electric heater 280, and each of the channels preferably has an aspect ratio (width/height, where the width is the width of the electrodes 112 and the height is the spacing between the electrodes 112 in the channels) that is greater than 1. This configuration minimizes stagnation within the channels defining the second fluidic path “E” through the electric heater 280 (FIG. 13 ). By minimizing stagnation, a uniform heating of the water within the fluidic circuit “E” is achieved. In addition, the channels within the second fluidic path “E” are configured to result in turbulent water flow through the second fluidic path “E” at the setpoint temperature. In some aspects of the disclosure, the water flow through the second fluidic path “E” has a Reynolds number of greater than 4000. The turbulent flow through the second fluidic path “B” also minimizes stagnation within the second fluidic path “E” to provide for more uniform heating of the water.
Although the heater assembly disclosed herein is disclosed in the context of an ohmic heater, the concepts disclosed herein are not limited to that type of heating. For example, other types of heater assemblies in accordance with the disclosure may include a recirculating flow path within the heater assembly like that disclosed above, where the volume of the flow path is sufficient to dispense a desired amount of hot water from a faucet at a steady temperature before being depleted and encountering a temperature drop. Moreover, the recirculating flow path can be heated by other heating means in the carrier 134, such as an electrical resistance heater. In such aspects of the disclosure, for example, the heated coils of a resistance heater may likewise be located in the carrier 134 of the heater and/or they may help to define alternating channels of a flow path. Similarly, the outer part of the flow path outside of the carrier 134 may likewise be defined by baffles 133, which may induce the flow to follow a circuitous path, thus achieving many of the benefits of the disclosure.
Although aspects of the disclosure have been described with reference to particular embodiments, it is to be understood that these aspects are merely illustrative of the principles and applications of the disclosure. It is therefore to be understood that numerous modifications may be made to the aspects of the disclosure and that other arrangements may be devised without departing from the spirit and scope of the disclosure as defined by the appended claims.
Persons skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary aspects of the disclosure. It is envisioned that the elements and features illustrated or described in connection with one exemplary aspect of the disclosure may be combined with the elements and features of another without departing from the scope of the disclosure. One skilled in the art will appreciate further features and advantages of the disclosure based on the above-described aspects of the disclosure. Accordingly, the disclosure is not to be limited by what has been particularly shown and described, except as indicated by the appended claims.

Claims

What is claimed is:

1. A system for heating water comprising:

a heater assembly including an electric heater, a housing defining a water reservoir, and a continuous fluidic circuit defined within the water reservoir, the continuous fluidic circuit including a first fluidic path and a second fluidic path, the first fluidic path having an inlet and an outlet, the second fluidic path communicating with the first fluidic path and having an inlet and an outlet, the second fluidic path having a circuitous configuration, the electric heater positioned to heat water passing along the second fluidic path within the fluidic circuit;

a recirculation pump coupled to the fluidic circuit operable to recirculate fluid through the fluidic circuit; and

a controller operable to actuate the electric heater to supply heat to the water passing through the second fluidic path of the fluidic circuit.

2. The system of claim 1, wherein the first fluidic path has a serpentine configuration.

3. The system of claim 1, wherein the circuitous configuration of the second fluidic path is a serpentine configuration.

4. The system of claim 1, wherein the electric heater is an ohmic heater and includes two or more electrodes, the two or more electrodes defining a portion of the second fluidic path.

5. The system of claim 1, wherein the housing includes a sleeve that defines a cavity, and further including a heater support received within the cavity, the electric heater supported within the heater support.

6. The system of claim 5, wherein the heater support includes baffles that define the first fluidic path.

7. The system of claim 1, wherein the first fluidic path encircles the second fluidic path, and the electric heater is centrally located with the water reservoir.

8. The system of claim 1, wherein the inlet of the second fluidic path is connected to the outlet of the first fluidic path, and the outlet of the second fluidic path is connected to the recirculation pump and to a faucet.

9. The system of claim 8, wherein the inlet of the first fluidic path is adapted to be coupled to a water source.

10. The system of claim 1, wherein the housing includes a sleeve having a first end and a second end, a first pressure plate secured to the first end of the sleeve, a second pressure plate secured to the second end of the sleeve, a power cap secured to the first end of the sleeve, and an end cap secured to the second end of the sleeve, the power cap and the end cap defining portions of the first fluidic path and the second fluidic path.

11. The system of claim 1, further including a temperature sensor, the controller electrically coupled to the heater, the temperature sensor, and the recirculation pump and being operable to maintain the fluid at a setpoint temperature.

12. The system of claim 1, wherein the second fluidic path is defined by channels, and the aspect ratio of each of the channels defining the second fluidic path is greater than 1.

13. The system of claim 1, wherein the channels of the second fluidic path are configured, is such that the water flow through the second fluidic path has a Reynolds number of greater than 4000.

14. A heater assembly comprising:

a housing defining a water reservoir;

a fluidic circuit defined within the water reservoir having a first fluidic path and a second fluidic path, the first fluidic path having an inlet and an outlet, the second fluidic path communicating with the first fluidic path and having an inlet and an outlet, the second fluidic path having a circuitous configuration, the first fluidic path connected to the second fluidic path to facilitate recirculation of the water through the fluidic circuit; and

an electric heater positioned to heat the water passing along the second fluidic path;

wherein the inlet of the first fluidic path is adapted to be coupled to a water source and the outlet of the second fluid path is adapted to be connected to a faucet.

15. The heater assembly of claim 14, wherein the second fluidic path includes channels having aspect ratios greater than 1 and is configured such that water flow through the second fluidic path has a Reynolds number greater than 4000.

16. The heater assembly of claim 14, wherein the first fluidic path has a serpentine configuration.

17. The heater assembly of claim 14, wherein the electric heater is an ohmic heater and includes two or more electrodes, the two or more electrodes defining a portion of the second fluidic path.

18. The heater assembly of claim 14, wherein the housing includes a sleeve that defines a cavity, and further including a heater support received within the cavity, the electric heater supported within the heater support.

19. The heater assembly of claim 18, wherein the heater support includes baffles that define the first fluidic path. 20 The heater assembly of claim 14, wherein the first fluidic path encircles the second fluidic path, and the electric heater is centrally located with the water reservoir.