DE19543761C2 - Detection device for the state of charge of a hot water tank - Google Patents

Description

The invention relates to a detection device for the percentage State of charge of a hot water tank with the characteristics of Preamble of claim 1.

Such a detection device is in DE 44 01 539 A1 described. The integral temperature sensor provides the information for the percentage of heat in the hot water tank. Is this Water in the hot water tank completely to the maximum adjustable target temperature is charged, then the display is shown "100%". The outlet temperature sensor ensures in the heating phase that that an indication is only given when near the hot water outlet there is a water temperature for normal use suitable is. This "usable hot water temperature" is, for example set to 40 ° C. Such a detection device enables an energy saver because the user is charged Detects hot water tank and therefore not unnecessary will switch on a reloading process.

In a detection device of the type mentioned at the beginning be guaranteed that the 100% display, or the maximum value of the Control voltage of the display device always occurs when the  DHW cylinder is fully charged to the maximum set temperature. This is theoretically unproblematic, because of series production Component tolerances are difficult to achieve. It can be in practice due to original component tolerances that the 100% display does not appear, even though the hot water tank is fully charged. The user then gets the impression that the Hot water storage device is not working properly because of the 100% display does not appear.

On the other hand, for the reasons mentioned, that the 100% display already appears when the hot water tank is not yet fully charged. This is not true either, however less disturbing for the user. Otherwise move out of the mentioned reasons also the lower ad values.

To at least approximately meet the requirement mentioned narrow-tolerance components are used and / or the Detection device can be used with any device during production be compared. Both are cost-intensive and production-related complex. In practice one will therefore try to set the limit values for to choose the control voltage so that taking into account all Component tolerances reached the limits of the display at 0 and 100% become.

The object of the invention is in a detection device a self-learning adaptation of the Propose control voltage.

According to the invention, the above object is characterized by the features of characterizing part of claim 1 solved.

This ensures that after installing the Hot water storage tank at the installation site and when it is first installed Heating up to the maximum set temperature (maximum controller position) of the resulting maximum control voltage value that the 100% display triggers, is saved so that when this occurs in the future maximum voltage value, the 100% display always appears. At the maximum of different device copies Control voltage value in its absolute amount due to  Component tolerances may be different. In any case, however, joins Full charge of the hot water tank with the maximum target temperature 100% display on. This eliminates the need for manufacturing to use tightly tolerated components or each device in the Align manufacturing. So without these measures, that the 100% display does not fail, even though the storage container is open maximum target temperature is fully charged, and the 100% display is not already occurs when the hot water tank is not yet fully open maximum adjustable target temperature is fully charged.

In a preferred embodiment of the invention there is a new one Save the maximum triggering the 100% display Control voltage value with each maximum charge of the Hot water tank with maximum target temperature.

Already for the first start-up To provide control voltage value for the 100% display, is in the embodiment of the invention on the production side on the first Storage space before the first - self-learning - coordination of the the maximum control voltage value corresponding to the 100% display an approximate maximum control voltage value is entered. This will then reach the maximum target temperature when fully charged for the first time overwritten with the current maximum control voltage value.

The detection device is designed so that in a typical Chilled water temperature of the water network between 10 ° C and 15 ° C Minimum value of the control voltage of the display device is present. Is the Chilled water temperature higher than that used for the display Value, the display shows another shortly before switching off State of charge that is not available to the user. On the other hand the cold water temperature is lower than the reference value, shows the Display before switching off by the outlet sensor State of charge 0%, and the user could unnecessarily recharge carry out. In an embodiment of the invention, the microcontroller advances Adjustment of the lowest display value when the value falls below the usable hot water temperature at the outlet temperature sensor occurring minimum control voltage value in a second Storage space. It is exploited that the shutdown signal of  Outlet temperature sensor the integral temperature sensor a signal delivers, which is a measure of the cold water temperature.

Further advantageous embodiments of the invention result from the dependent claims and the following description. In the Show drawing:

Fig. 1, a hot water storage heater with Ladezustand- detecting means schematically

Fig. 2 is a block diagram of the detection means,

Fig. 3 is a diagram of the control circuit and the percentage display of the display device and

Fig. 4 typical curves of the output voltage of the outlet temperature sensor ( Fig. 4a) and the output voltage of the integral temperature sensor ( Fig. 4b) and the display value ( Fig. 4c) in a charge and discharge cycle when the controller is set to the maximum target temperature.

An electric heater ( 2 ) is arranged at the bottom in a hot water tank ( 1 ) of a heater. At the bottom, a cold water supply line ( 3 ) opens into the hot water tank ( 1 ). A hot water outlet pipe ( 4 ) opens at the top. The cold water pipe ( 3 ) and the hot water pipe ( 4 ) lead to a tap valve ( 5 ) of a tap ( 6 ).

The heater ( 2 ) can be controlled by a temperature controller ( 7 ). The target hot water temperature can be set on a setpoint device ( 8 ). A temperature sensor ( 9 ), which is connected to the controller ( 7 ), is arranged next to the radiator ( 2 ). When the set target temperature is reached, the controller ( 7 ) switches off the radiator ( 2 ).

An integral temperature sensor ( 10 ) extends over the height (L) of the hot water tank ( 1 ). An outlet temperature sensor ( 11 ) is arranged at the top of the hot water tank ( 1 ) close to the mouth of the hot water outlet line ( 4 ). The temperature sensors ( 10 , 11 ) are arranged on the outside of the hot water tank ( 1 ) in FIG. 1. You could also be provided inside this.

The temperature sensors ( 10 , 11 ) are connected to a detection device ( 12 ) ( Fig. 2). This works with a microcontroller ( 13 ) on which the output voltage (Ui) of the integral temperature sensor ( 10 ) and a signal processing circuit ( 15 ) (A / D converter) via a signal processing circuit ( 14 ) (A / D converter). the output voltage (Ud) of the outlet temperature sensor ( 11 ).

The microcontroller ( 13 ) is assigned two non-volatile, programmable memory locations ( 16 , 17 ) which are formed, for example, by an EEPROM. On the output side, the microcontroller ( 13 ) generates a control voltage for a display device ( 18 ). This shows the respective charge level of the hot water tank ( 1 ) in percent.

Fig. 3 shows the course of the display values from 0% to 100% depending on the control voltage (Ui). At a maximum value (Umax) of the control voltage (Ui) the display shows "100%". With a minimum value (Umin) of the control voltage (Ui) there is in principle the 0% display.

The device-specific voltage value (Umax) is stored in memory location ( 16 ). Correspondingly, the voltage value (Umin) is stored in the memory location ( 17 ).

In FIG. 4, the voltage waveforms of Ud and Ui, and the percentage display in a typical charge and discharge cycle at maximum regulator position (maximum target temperature) are shown. It is assumed that the radiator ( 2 ) is switched on at time (t1). The display device ( 18 ) is initially still switched off or shows "0%". This makes sense because there is initially no usable heat content in the hot water tank ( 1 ). At time (t2), a usable mixed water temperature, for example 40 ° C., is reached at the outlet temperature sensor ( 11 ). The signal processing circuit ( 15 ) is designed so that the voltage (Ud) now changes from "off" to "on" ( FIG. 4a). Due to the previous off state, the display device ( 18 ) was kept switched off or set to 0%. Corresponding to the charge up to time (t2), the output voltage (Ui) of the integral temperature sensor ( 10 ) has also risen to Ui1 ( FIG. 4b). The display device ( 18 ) now shows a value corresponding to the percentage charge. The percentage display value increases as the hot water tank ( 1 ) is loaded further.

At the time (t3) the set maximum target temperature has been reached. The controller ( 7 ) now switches off the radiator ( 2 ). The voltage (Ui) has reached its maximum value (Umax). This maximum value (Umax) is now stored in memory location ( 16 ). A previously saved maximum value (Umax) is overwritten. The absolute value of the voltage (Umax) depends on tolerances in the tolerance chain: controller, integral temperature sensor, signal processing circuit. By storing the respective maximum value (Umax), the tolerances of the tolerance chain are compensated so that the 100% display is correct. As long as the device-specific value (Umax) is not stored in the memory location ( 16 ), but an approximately preset value, the 100% display already takes place at a time (t3 ') (see the dashed line in Fig. 4c) that is shortly before the time (t3). The user therefore receives the 100% display somewhat prematurely - before the first charging cycle with the maximum controller setting has been completed.

Since the stored value (Umax) is set with each recharge with maximum target temperature is updated, any will Corrected data loss of storage space. In case of malfunctions, for example with regard to electromagnetic compatibility (EMC) to avoid "wrong learning" from Umax can be provided be that the "learning" of the value (Umax) by additional Arithmetic operations, such as averaging, is secured.

If the controller ( 7 ) is not set to the maximum setpoint temperature, but to a different setpoint temperature, the stored value (Umax) is not overwritten.

In Fig. 4 it is assumed that at time (t4) the hot water tank ( 1 ) is discharged by hot water pegs.

The voltage (Ui) (see FIG. 4b) and the display (see FIG. 4c) decrease accordingly. At time (t5), the usable hot water temperature, for example 40 ° C., on the outlet temperature sensor ( 11 ) is below. The voltage (Ud) now switches from "On" to "Off". This switch-off information is a measure of the respective cold water temperature of the feed line ( 3 ). At time (t5) there is a voltage (Ui2). If this deviates by an amount up or down from the value (Umin) stored in the storage space ( 17 ), the value (Umin) of the storage space ( 17 ) is overwritten accordingly. This charging process is deliberately slow, that is, small amounts are set for the changes, because on the one hand the cold water temperature does not change constantly and on the other hand the tap behavior of the user is unknown. For example, if the user has emptied the hot water tank ( 1 ) so far that the outlet temperature sensor ( 11 ) still detects a usable temperature, but most of the hot water has already been drawn, and then there is a long tap break, then the cold water heats up in the hot water tank ( 1 ) gradually to room temperature, so that the integral temperature sensor ( 10 ) cannot detect the actual cold water temperature when tapping. It is therefore envisaged that this learning process only takes place after a larger number of taps in order to fully compensate for the influence of the cold water temperature. Then the display is also optimally adapted to a changing cold water temperature.

At time (t5) the display switches off or to 0%.

The self-learning storage of the correct values of Umax and Umin depending on the operating conditions or their displacement in the direction of the arrows (d1, d2, d3,) (see FIG. 3) ensures that the characteristic curve of FIG has a slope adapted to the respective operating conditions, so that the percentage display shows the respective charge state quite precisely.

Claims (8)

1.Detection device for the percentage state of charge of a hot water tank with an integral temperature sensor extending over the height of the hot water tank and an outlet temperature sensor arranged near the hot water outlet at the top in / on the hot water tank, the temperature sensors being located on a microcontroller for a display device and the microcontroller Controls the display device with a control voltage corresponding to the respective percentage charge, characterized in that the microcontroller ( 13 ) in a first step to tune the 100% display value to the maximum control voltage value (Umax) which occurs when the maximum charge of the hot water tank ( 1 ) is reached with the maximum target temperature Storage space ( 16 ) is stored, with the 100% display occurring in subsequent operation when this control voltage value (Umax) occurs. 2. Detection device according to claim 1, characterized in that the microcontroller ( 13 ) stores the minimum control voltage value (Umin) occurring when the usable hot water temperature falls below the outlet temperature sensor ( 11 ) in a second memory location ( 17 ). 3. Detection device according to claim 1 or 2, characterized in that an approximate maximum control voltage value is stored in the first memory location ( 16 ) before the first adjustment of the maximum control voltage value (Umax). 4. Detection device according to claim 3, characterized, that the approximate maximum control voltage value is chosen to be smaller than the expected maximum control voltage value (Umax), so that the 100% display before voting occurs before full charge. 5. Detection device according to one of the preceding claims 2 to 4, characterized in that an approximate minimum control voltage value (Umin) is stored in the second memory location ( 17 ) before the first adjustment of the lowest display value. 6. Detection device according to one of the preceding claims, characterized in that the maximum control voltage value (Umax) corresponding to the 100% display is stored again with each full charge of the hot water tank ( 1 ) with the maximum target temperature. 7. Detection device according to one of the preceding claims 1 to 5, characterized in that maximum control voltage values of a plurality of full charges are recorded at the maximum target temperature and the resulting value is stored as the maximum control voltage value (Umax) in the first memory location ( 16 ). 8. Detection device according to one of the preceding claims, characterized in that the memory location ( 16 ) or the memory locations ( 16 , 17 ) are formed by a non-volatile, programmable memory (EEPROM).