Tankless water heater and electronic point of use water heater comprising the same

Abstract

A water heater including an inflow terminal for connecting a tankless water heater to a cold water supply and an outflow terminal for connecting the tankless water heater to a tap. A fluid channel proves a fluid connection from the inflow terminal to the outflow terminal. A heat element arrangement is arranged at or within at least a section of the fluid channel for transferring heat to fluid present within the fluid channel. An electronic controller is configured to control a heating power provided to the heat element arrangement. A flow sensor is arranged at or within the fluid channel downstream the heat element arrangement. The electronic controller is further configured to detect the presence of air bubbles within the fluid channel based on a change of a flow signal provided by the flow sensor and to adapt the heating power provided to the heat element arrangement in reaction to the determination of air bubbles.

Claims

1. A tankless water heater comprising: an inflow terminal for connecting the tankless water heater to a cold water supply; an outflow terminal for connecting the tankless water heater to a tap; a fluid channel providing a fluid connection from the inflow terminal to the outflow terminal; an electric heating element arranged at or within at least a section of the fluid channel, the electric heating element being configured to heat fluid present within the fluid channel; a flow sensor arranged at or within the fluid channel downstream of the heating element; and an electronic controller configured to: control a heating power provided to the electric heating element, detect the presence of air bubbles within the fluid channel based on a change of a flow signal provided by the flow sensor, in response to air bubbles being detected, adapt the heating power provided to the electric heating element, and delay the onset of providing heating power to the electric heating element after the flow signal becomes indicative of a start of a tap event.

2. The tankless water heater according to claim 1, further comprising: a first temperature sensor configured to determine a temperature of fluid within the fluid channel upstream the electric heating element; and a second temperature sensor configured to determine a temperature of fluid within the fluid channel downstream the electric heating element.

3. The tankless water heater according to claim 2, wherein the second temperature sensor is arranged between the flow sensor and the heat element arrangement with respect to the fluid channel.

4. The tankless water heater according to claim 2, wherein the electronic controller is further configured to adapt the heating power provided to the electric heating element based on a difference between the temperature determined by the second temperature sensor and a predetermined set temperature.

5. The tankless water heater according to claim 4, further comprising: a throttle valve, wherein the electronic controller is further configured to decrease the flow rate using the throttle valve responsive to the predetermined set temperature not being met.

6. The tankless water heater according to claim 5, wherein the electronic controller is further configured to adjust the flow rate using the throttle valve in response to the temperature determined by the first temperature sensor being low.

7. The tankless water heater according to claim 1, wherein at least the flow sensor, the fluid channel, the electric heating element, and the electronic controller are arranged within a housing.

8. The tankless water heater according to claim 1, wherein the flow sensor includes a spinning wheel, and wherein the flow signal is indicative of a spinning rate of the spinning wheel.

9. The tankless water heater according to claim 1, wherein the electronic controller is further configured to stop the provision of heating power to the electric heating element in response to a change in flow signal being indicative of the presence of air bubbles.

10. The tankless water heater according to claim 9, wherein the electronic controller is further configured to determine the presence of air bubbles in the fluid channel using a characteristic frequency pattern analysis on the flow signal provided by the flow sensor.

11. An electronic controlled point of use water heater comprising: an inflow terminal for connecting to a cold water supply; an outflow terminal for connecting to a tap; a fluid channel providing a fluid connection from the inflow terminal to the outflow terminal; an electric heating element arranged at or within at least a section of the fluid channel, the electric heating element being configured to heat fluid present within the fluid channel; a flow sensor arranged at or within the fluid channel downstream the heating element; and an electronic controller configured to: control a heating power provided to the electric heating element, detect the presence of air bubbles within the fluid channel based on a change of a flow signal provided by the flow sensor, and in response to air bubbles being detected, adapt the heating power provided to the electric heating element such that the heating power is greater than zero.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 schematically and exemplarily illustrates a tankless water heater according to the invention.

DETAILED DESCRIPTION

(2) Embodiments of the present disclosure are described herein. It is to be understood, however, that the disclosed embodiments are merely examples and other embodiments can take various and alternative forms. The figures are not necessarily to scale; some features could be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. As those of ordinary skill in the art will understand, various features illustrated and described with reference to any one of the FIGURES can be combined with features illustrated in one or more other FIGURES to produce embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. Various combinations and modifications of the features consistent with the teachings of this disclosure, however, could be desired for particular applications or implementations.

(3) FIG. 1 schematically and exemplarily illustrates a tankless water heater 10 according to an embodiment of the present invention. The tankless water heater 10 comprises in this example an optional housing 20 within which a fluid channel 16 extends from an inflow terminal 12 to be connected to the cold water supply to an outflow terminal 14, which is designed to be connected, for instance, to a tap or other point of use at which warm or hot water is desired.

(4) During its passage through tankless water heater 10, fluid channel 16 is arranged in contact with a heat element arrangement 2 which comprises a plurality of heat elements to transfer heat energy, in particular electric heat energy, to the water within the fluid channel 16.

(5) A single flow sensor 1 is arranged on the hot side downstream the heat element arrangement at or within fluid channel 16. A plurality of different flow sensors 1 for providing a flow signal indicative of a flow through fluid channel 16 are known, preferably, flow sensor 1 comprises a spinning wheel and provides a signal indicative of a spinning speed of the spinning wheel.

(6) Flow sensor 1 is arranged downstream to be capable of detecting air bubbles within fluid channel 16 as a result of air contamination of the incoming water, i.e. water entering tankless water heater 10 through inflow terminal 12, and likewise air bubbles created by the solvent evaporation

(7) The temperature range within which water leaves the outflow terminal 14 is preferentially between 40° C. and 100° C., more preferably between 60° C. and 95° C.

(8) Upstream and downstream of heat element arrangement 2 is provided a first temperature sensor 3 and a second temperature sensor 4, respectively. Temperature sensor 3 senses the incoming water side, temperature sensor 4 the outgoing water side after the water was heated by heat element arrangement 2. Additionally, a throttle valve 5 is arranged on the cold or incoming water side and can be used to adjust the flow through fluid channel 16. While throttle valve 5 is illustrated on the cold water side, it is of course contemplated to provide throttle valve 5 on the warm or hot water side since the flow through fluid channel 16 is equal through the entire tankless water heater 10.

(9) An electronic controller 6 is further provided which is configured to control the heating output of the heat element arrangement 2 such that the temperature sensed by temperature sensor 4 is close to a set point temperature, which is preferably defined by a set point monitor device 7, which can be provided integrated in electronic controller 6. In case the available heating power is not enough to satisfactorily heat the water to the desired set point temperature, the flow of water can be reduced by means of throttle valve 5 such that the available heating power is then sufficient. This will, for instance, be the case when the supplied water temperature is low or the designated set point temperature is high.

(10) All sensor elements 1, 3 and 4 as well as throttle valve 5 are illustrated to be connected via a wire 8 to electronic controller 6. It is of course contemplated that one, more or all of the sensor elements can communicate by other means, for instance wirelessly, with electronic controller 6.

(11) Tankless water heater 10 starts heating, more precisely electronic controller 6 supplies energy to heat element arrangement 2, once flow sensor 1 detects a tapping event with a delay to avoid overheating heat element arrangement 2. The delay is applied to ensure that no remaining air bubbles are present in a heating chamber, i.e. the region of fluid channel 16 in which water can be heated by heat element arrangement 2.

(12) Further, upon detection of air bubbles through controller 6 based on sensor signals by flow sensor 1, heating will be stopped. Air bubbles can be determined because of an instantaneous change rate of the rotation speed of the spinning wheel of the flow sensor 1. Additionally or alternatively, a characteristic frequency pattern analysis of the flow sensor signal is used for evaluation by electronic controller 6.

(13) While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes can be made without departing from the spirit and scope of the disclosure. As previously described, the features of various embodiments can be combined to form further embodiments of the invention that may not be explicitly described or illustrated.

(14) List of Reference Numbers: 1 flow sensor 2 heat element arrangement 3 temperature sensor 4 temperature sensor 5 throttle valve 6 electronic controller 7 set point monitor device 8 wire 10 water heater 12 inflow terminal 14 outflow terminal 16 fluid channel 20 housing