US20200025418A1

US20200025418A1 - Procedure for Displaying Performance Data on the Front of a Tankless Electric Water Heater

Info

Publication number: US20200025418A1
Application number: US16/040,782
Authority: US
Inventors: Hubert Nolte
Original assignee: Stiebel Eltron GmbH and Co KG
Current assignee: Stiebel Eltron GmbH and Co KG
Priority date: 2018-07-20
Filing date: 2018-07-20
Publication date: 2020-01-23
Also published as: DE102019004961A1

Abstract

The invention describes the procedure for displaying performance data on the front of a tankless electric water heater. At least one of the performance conditions is stored in the electronic control unit and is available to the display. A savings E is determined from a reference value R and a time value Z and is made available to be shown on the display. The reference value R contains at least one loss value V of another water heater and the time value Z is an input from the tankless electric water heater. The savings E represents a measure of the energy savings of the tankless water heater as contrasted with the other water heater.

Description

FIELD OF THE INVENTION

The invention describes the procedure for displaying performance data on the front of a tankless electric water heater. At least one of the performance conditions is stored in the electronic control unit and is sent to the digital display.
Technological advancements make it possible to equip household appliances with the ability to display usage data. For example, the consumed amount of electricity in KWh can be displayed. The momentary electricity usage can be shown, or be tallied over a period of time.
The separate document, DE 38 42 857 C3, describes how a tankless electric water heater equipped with a measuring system can determine usage. The amount of electric current flowing through a heating element can be captured by a measuring device. The amount of electrical energy being consumed can be displayed as water is being drawn through the unit.
The task of the invention is to make a procedure available by which the benefit of the tankless electric water heater is demonstrated in a simple manner.

SUMMARY OF THE INVENTION

A savings E is determined from a reference value R and a time value Z. The savings E is made available to the digital display. The reference value R contains at least one value from another water heater. The time value Z is an input of the tankless electric water heater. The Savings E represents a measure of the energy savings of the tankless water heater as contrasted with the other water heater.
The time value Z for the tankless water heater includes the time for which no hot water is drawn, or the time value is derived from hot water being produced by the tankless unit.
The time value Z can also be a virtual input or via a mobile device, especially if the data of the tankless electric heater are already contained in the mobile device or connected via mobile link.
The time value Z can also include the condition when the tankless unit is ready to deliver hot water but not in operation. This is the standby condition.
The time value Z can also mean the time during which the tankless unit is connected to the power supply, is ready for operation or is actively heating water.
A calculation of the savings E is executed when the tankless water heater produces no readiness energy losses (standby losses) or the electric heating element(s) are shut off.
The reference value R is provided to the tankless water heater either over an input device or over the internet.
The reference value R is dependent and built upon case examples. Case examples are shown to the user on the display and he/she can select. The user can modify these case examples.
The time value Z is generated from the tankless water heater itself.
The savings E is dependent on the reference value R of another hot water heater and calculated using the time value Z of the tankless water heater.
The loss value V is advantageous based on the readiness energy loss (standby loss) of the reference hot water heater.
Additionally, the loss value V is the readiness energy loss (standby loss) of a hot water heater that contains a storage tank.
The invention further executes the calculation of the savings E during the time intervals during which no hot water is being produced. The readiness energy loss value (standby loss) is calculated with a downtime of the tankless water heater. A readout of the savings E appears temporalily on the display so that the user can see how large the savings E is.
A calculation of the savings E benefit follows when the tankless water heater does not produce any readiness energy losses (standby losses).
Parameters like a distribution loss value and/or money value are drawn on to determine the reference value.
The savings E readout follows in a predetermined time interval of about 5 minutes, one hour, one day, one week or in a similar time interval.
Further, the savings E contains a parameter PE such as a current value (KWh), money value ($) or CO2 value (kg) and is correspondingly shown on the display as current value, money value or CO2 value.
A trigger signal which is dependent on the operation status of the tankless water heater, determines the idle period when a further calculation of the savings E can take place. The timing module of the CPU provides the trigger signal.
A state-of-the-art tankless water heater that is operated by a state of the art process, features a central process controller combined with an integrated operating station and display. From the inlet cold water connection, the water flows through the CPU controlled modulating heating element where it is heated to temperature.
A comparator unit is provided that is combined with a savings readout.
The comparator unit is combined with a timing module.
The timing module is connected to a trigger unit.
A trigger signal which is dependent on the operation status of the tankless water heater, determines the idle period when a further calculation of the savings E can take place. The timing module of the CPU provides the trigger signal.
The innovation includes for the entry of parameters via the entry unit. Other forms of entry are possible, for example via touchscreen or speech recognition.
Also, it may be advantageous to operate the tankless water heater with a mobile device. This can be done either via cable connection or Wifi through the internet. A mobile device may include a smart phone, tablet computer, or other mobile operating device.
The data entry can be accomplished via mobile device touchscreen but this is not mandatory. Speech recognition, touchscreen computer operation or control over service menus may also be done.
A state-of-the-art tankless water heater that is operated by a state of the art process, features a central process controller combined with an integrated operating station and display. From the inlet cold water connection, the water flows through the CPU controlled modulating heating element(s) where it is heated to temperature.
The comparator unit is integrated to display an energy savings readout.
The comparator unit is combined with a timing module.
The timing module is connected to a trigger unit. A trigger signal which is dependent on the operation status of the tankless water heater, determines the idle period when a further calculation of the savings E can take place. The timing module of the CPU provides the trigger signal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic representation of a tankless electric water heater at a point of use.

FIG. 2 shows a process sequence for evaluation of energy savings.

DETAILED DESCRIPTION OF EMBODIMENTS

It is to be understood that the figures and descriptions of the present invention have been simplified to illustrate elements that are relevant for a clear understanding of the present invention, while eliminating, for purposes of clarity, many other elements which are conventional in this art. Those of ordinary skill in the art will recognize that other elements are desirable for implementing the present invention. However, because such elements are well known in the art, and because they do not facilitate a better understanding of the present invention, a discussion of such elements is not provided herein.
The present invention will now be described in detail on the basis of exemplary embodiments.
FIG. 1 demonstrates an application of a tankless electric water heater (1) with an integrated user panel and display (4). The tankless water heater is equipped with a cold water connection (2) and hot water piping (3). The integrated user panel and display (4) comprises a temperature readout (5), a savings display (6), an operation button (7) and an entry element (8) in order to navigate the operation menu. The hot water outlet piping (3) can be combined with a least one point of use (9), here a shower head, or it can be provided in a loop with a least one point of use (9).
In order to show the user in a simple way the energy usage of his/her electric tankless water heater (1), the savings E of the heater, as opposed to a common standard tank-type unit, is shown at the savings display (6).
A centrally located tank-type water heater has additional energy costs for the water storage and distribution to the point of use (9), in comparison to a tankless water heater (1). The tankless unit (1) is installed near the point of use (9), and as a consequence there is almost no cost due to heat dissipation losses for storage and longer distribution pipe runs.
When the tankless water heater (1) is installed near the usage point (9) and only drawing electric power when the water is flowing through, over 99% of the energy used goes for heating the water. There are no energy losses for the time when no hot water is required. A savings E is shown on display (4) of the integrated operating panel, compared with the calculated value for an electric storage tank during same time that no water was used. This represents the standby loss savings e1.
A draw savings e2 is compared with an electric storage tank when hot water is being drawn through a longer pipe run than with the shorter run (3) to the draw off point as depicted in FIG. 1.
The savings E of the tankless water heater compared with an electric storage tank is calculated for the first time interval in the following manner:
E=∫ _t1 ^t2 e1+e2
E=Savings (in %)
e1 Standby Savings (Standby)
e2 Draw Savings (Heating)
In the simplest case the control board with microprocessor calculates the tankless water savings E once per second, totaled and shown on the display (4). If the user chooses, at the unit's entry station (8) the value T can be adjusted to reflect a local power cost.
The standby losses of the reference unit (tank-type) are programed into the operating station and display (4) with a well-established average value in (KWh/day). The duration of the standby and heating events are captured by the processor by collecting the tankless water heater activation and deactivation duration. This follows from a trigger signal that is provided by a trigger unit.
The corresponding saved and calculated amount of energy is totaled based on the operating mode. The resulting sum of the assessed savings E is shown on the savings display (6).
E=∫ _t1 ^t2 e1+e2
The detection of the operating mode, standby or heating, can either be accomplished by a flow dependent signal from the water flow, or monitoring the power intake for heating through which an exceeding or undercutting of a power level can be _“observed” by the electronics. The trigger unit recognizes the duration of the operating mode.
FIG. 2 shows a process sequence. In Block B1 the parameters for the assessment of energy savings E are entered (8), like the reference value R, a power value kWh, a monetary value ($), a CO2 value (kG), a valid currency, the current power price and/or the loss value.
Further, the integrated user panel and display (4) are also designed for entry of standard values (SV) for the operation of the tankless water heater (1). The standard values (SV) include a setpoint temperature of the hot water, an anti-scald temperature and/or additional control parameters for the standard operation of the tankless water heater (1).
In Block B2 the operating mode Heating H or Standby S is determined. As a benefit, the trigger unit can also be located here.
In Block B3 standby savings E2 is calculated according to a pre-determined time interval, for example 1×/sec. Also, a continual calculation of the standby savings E2 can be determined here.
In Block B4 the draw savings E1 is determined according to a pre-determined time interval or continuously.
In Block B5 the savings E is added up and in the savings display 6 shown as cumulative amount from e1 and e2.
In Block B6 the updating of the cumulative amount of savings E can occur hourly, daily or on a continual basis.
It is a beneficial arrangement when the tankless water heater 1 is connected via router with the Internet and the entry of the local power rates or currency can be automatically accomplished.
The reference system can further be differentiated through additional entries at the integrated user panel and display 4. With the additional parameter PE, like the entry of specific readiness heat loss (standby) value f1 could be useful for the case when the tankless water heater replaces a tank with a recirculation system and the reference system with the standby loss as parameter needs to be modified.
Further, a specific distribution loss factor f2 can be entered as parameter PE which is a measure for the losses in the pipe run from the tank-type water heater to the point of use or in a loop distribution.
The display showing the usage savings 6 can be carried out in (KWh), (Kg CO2) and/or in the local currency in (Euros) or ($). For expediency these parameters can be provided via the Internet which simplifies reckoning.
As a benefit, a readout of the yearly reduced CO2 emission can be carried out relative to the reference system in % of the average CO2 production of an average household.
The savings E can be called up on the display 4 according to need, can be continually displayed, can be done ala a prescribed time schedule, or through an entry at the operating station and display 4.
A trigger signal, dependent on what state of operation the tankless water heater 1 is in, produces the determination of the downtimes and the calculation of the savings E.
The trigger signal is made available by the time module of the comparator unit.
The time module is connected to a trigger unit.
While this invention has been described in conjunction with the specific embodiments outlined above, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiments of the invention as set forth above are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the inventions as defined in the following claims.
It is noted that citation or identification of any document in this application is not an admission that such document is available as prior art to the present invention.

Claims

1. A method for displaying performance data of a tankless electric water heater having a display, an electronic control unit, and heating elements, where at least one performance condition is stored in the electronic control unit and is available to the display, the method comprising:

determining a savings E based on a reference value R and a time value Z; and

making the savings E available to and shown on the display;

wherein the reference value R contains at least one loss value V of another water heater;

wherein the time value Z is an input of the tankless electric water; and

wherein the savings E represents a measure of the energy savings of the tankless water heater as contrasted with another water heater.

2. The method according to claim 1, further comprising:

generating the time value Z dependent on whether hot water is being drawn; and

then determining the savings E when the tankless water heater is not producing any readiness energy losses (standby losses) or the heating elements are not activated.

3. The method according to claim 1;

wherein the savings E is determined from an initial standby-savings e1 during standby, from a draw-savings e2 during a hot water draw, or from both.

4. The method according to claim 1;

wherein the energy savings E contains a standby loss value of a hot water heating device other than the tankless electric water heater.

5. The method according to claim 4;

wherein the tankless electric water heater has an integrated user panel and display configured to accept entry of the standby loss value.

6. The method according to claim 4;

wherein the determination of the savings E follows in time intervals in which the tankless water heater is not heating water;

wherein the standby loss value is calculated with a downtime; and

wherein a readout of a comparison of the savings E compared with a calculated value for an electric storage tank during same time that no water was used is at least temporarily shown on the display.

7. The method according to claim 1;

wherein the reference value R is determined based on a distribution loss value, a money value, or both.

8. The method according to claim 1;

wherein a statement of the savings E takes place in a predetermined time interval.

9. The method according to claim 1;

wherein the predetermined time interval is selected from the group consisting of 5 minutes, an hour, a day, a week, or any combination or multiple thereof.

10. The method according to claim 1;

wherein the savings E contains at least one parameter selected from the group consisting of a power value (kWh), a money value ($), and a CO2 value (kG); and

wherein the at least one parameter is displayed on the display.

11. The method according to claim 1;

wherein a trigger signal, dependent on a state of operation the tankless water heater, produces determination of downtimes and the determination of the savings E; and

wherein the trigger signal is made available by a time module of a comparator unit.

12. A tankless water heater, configured to perform the method of claim 1, comprising:

an electronic control unit;

with a cold water inlet connection;

an electronically controlled heating element configured to heat incoming cold water; and

a comparator unit that is connected to the display to show the savings E;

wherein the comparator unit is connected to a timing module;

wherein the timing module is connected to the trigger unit; and

wherein the trigger unit is configured to produce a trigger signal, dependent on the state of the tankless water heater operation, for determination of downtimes and calculation of the savings E.