DE19648652A1 - Water heating device with layered storage tank - Google Patents

Abstract

The heating device has a layered storage tank (1), a solar collector (10) and a primary heat exchanger (26) heated via a burner. The cold water is supplied to the base of the storage tank, and the warm water is extracted from its top. The storage tank has two secondary heat exchangers (8,21), respectively connected to the solar collector and the primary heat exchanger on their primary side, and is connected in series on their secondary side. The operation of a circulation pump (6) for the solar collector is controlled by a number of temperature sensors (35,41,49).

Description

The invention relates to a water heater with a stratified tank according to the preamble of claim 1.

In the previously known such water heaters, there was a switching device provided through which the stratified storage either via the solar collector or via the primary heat exchanger acted upon by a burner, be could be recharged.

However, this results in the disadvantage that the solar energy is only used could, if this alone led to a corresponding charging of the stratified storage was enough. But because on many days the solar energy is of a given size of the solar collector is not sufficient to match the hot water requirement Allowing charging of the stratified storage alone can be a considerable part of the Available solar energy cannot be used.

The aim of the invention is to avoid this disadvantage and a water heater to propose a very extensive use of the suns enables energy and still provides safe and sufficient warmth water guaranteed.

According to the invention this is in a water heater of the type mentioned achieved by the characterizing features of claim 1.  

The proposed measures make it possible to use the water over the Son preheat associated collector and preheat if necessary reheat the secondary heat exchanger charged by the primary heat exchanger. In this way, the available solar energy can also be used if it is available too little and not sufficient on its own would be to be able to charge the stratified storage.

The features of claim 2 result in the advantage of a very simple one Construction of the water heater. This solution is also suitable for retrofitting existing, exclusively burner-heated water heaters. It is single for that Lich necessary, the secondary heat exchanger of a solar system or another heat source, for example a heat pump, in the existing bypass line and integrate it into the regulation.

The features of claim 3 result in a division of the stratified storage, the lower part of the stratified storage tank from the secondary heat exchanger of the solar system is heated and the upper part of the stratified storage by the burner heated Primary heat exchanger associated secondary heat exchanger is heated. You can the two circuits are operated independently of one another. The more common show in the lowest area of the stratified temperature sensors a temperature sensor in the lowest cold water fume cupboard, which leads to the secondary heat exchanger the solar system leads to be replaced. In the same way, one for controlling the Charging circuit of the upper part of the stratified storage, in the middle area of the layer temperature sensor arranged by a cold water outlet in the middle arranged temperature sensors to be replaced.

The lower part of the stratified storage can be charged when the Temperature in the area of the outlet of the solar collector higher than the temperature in lowest area of the stratified storage.  

The features of claim 4 have the advantage that the terms are too short Circulation pump arranged in the solar system, which are in operation for the Flow through the secondary heat exchanger acted upon by the solar collector ensures.

The speed of the circulation pump depends on the type of pump that is to be used load of heat in the heat exchanger and the pressure losses in the bypass line. It is essential that one corresponding to the line and the temperature difference Flow is set.

A temperature sensor specified in the middle hot water supply can be used safely be made that heat is inserted into the stratified storage during operation of the solar system is brought.

Due to the features of claim 5, it is possible on the one hand in high sunshine charge the entire stratified storage tank via the solar system and, on the other hand, almost completely missing solar radiation over the entire stratified storage the burner-heated primary heat exchanger, or the one assigned to it Charge secondary heat exchanger so that in all cases the entire content of the layer can be used.

In addition, it is also possible in this way to store the strata in certain sections to a temperature, for example 60 °, which is sufficient to endanger a to prevent legionella from multiplying. The stratified storage only needs to do this to be fully heated via the burner-heated primary heat exchanger.

In all cases it makes sense as a charge pump depending on the hot water temperature infinitely variable pumps to provide the temperature of the respective charging circuit.

The invention will now be explained in more detail with reference to the drawing. Show:  

Fig. 1 to 3 schematically and various embodiments of inventive inventive Zerhei

Fig. 4 is a diagram of the flow rate of a circulation pump as a function of the temperature.

The same reference numerals mean the same details in all figures.

In the embodiment according to FIG. 1, there is a stratified storage tank 1 with a cold water inlet 2 , a process water outlet 30 and two temperature sensors 3 , 31 , of which the former is arranged in the lowest region 50 . In this area 50 a Kaltwas serabzug 4 is further arranged, which is connected via a line 5 to a pump 6 and further via a line 18 to a secondary branch 7 of a secondary heat exchanger 8 of a solar system 51 . A heat exchanger 8 is connected by means of a line 19 to a secondary branch 20 of a secondary heat exchanger 21 of a heat generator and further via a line 28 and a hot water inlet 29 to the uppermost region 52 of the store. A temperature sensor 32 is arranged in the hot water line 28 .

The primary branch 22 of the secondary heat exchanger 8 is connected via lines 16, 17 to a solar controller 14 - including a pump 15 - which is further connected via a return line 11 and a flow line 12 to a solar collector 10 . A temperature sensor 13 is located on the uppermost area of the solar collector 10 .

The solar controller 14 , which has a target value transmitter 62 and a differential transmitter 64 , is on the output side with drives 53 , 55 of pumps 24 , 6 and an actuator 58 of a gas valve 57 via control lines 83 , 75 , and 71 , and on the input side with temperature sensors 3 , 13 , 31 , 32 connected via control lines 74 , 72 , 73 and 70 .

62 preset desired temperature below the above the setpoint generator by about 5-10k at the temperature sensor 31, the water charging pump starts 6 to promote. Cold water is drawn off via the cold water drain 4 from the lowermost area 50 of the memory 1 and by means of the pump 6 via the lines 5 and 18 , the secondary branch 7 of the heat exchanger 8 of the solar system 51 , the line 19 , the secondary branch 20 of the heat exchanger 21 , the line 28 and the hot water inlet 29 conveyed into the uppermost area 52 of the memory 1 .

If the temperature in the collector 10 , which is detected by the temperature sensor 13 , is greater than the temperature at the temperature sensor 3 in the lowest storage area 50 , which is determined by the controller, the pump 15 of the solar system 51 begins to deliver. The process water flowing through the secondary branch 7 can thus be heated by solar energy.

If the collector temperature is lower than the temperature at sensor 3 or if, despite pump 15 running, the set temperature at sensor 32 is not reached after a certain time after heating has started, the heat generator and the associated pump 24 are started. The process water flowing through the secondary branch 20 of the heat exchanger 21 can thus be heated by the heating medium flow flowing through the pump branch 22 .

If a controllable pump is used, the minimum flow rate is set at the beginning; if a single-stage pump is used, this is initially clocked. If the target temperature set via the target value transmitter 62 is reached on the temperature sensor 32 , a single-stage pump begins to deliver continuously until the temperature falls below the target temperature or the heating process is ended.

The speed of an adjustable pump is set depending on the temperature at the temperature sensor 32 .

If the desired temperature is reached at the temperature sensor 3 located in the lowest area 50 , the heating process is ended. The pump 6 and possibly the pumps 15 and 24 and the heat generator are put out of operation.

In the water heater of FIG. 2, the memory 1 in an upper region 43 which is heated by a heat generator, and a lower portion 42, which is heated via an So Lara layer 51 is divided. The memory 1 has a cold water inlet 2 in the lowest area 50 and a process water outlet 30 in the top area 52 .

Approximately in the middle of the lower area 42 of the memory 1 there is a switch-on temperature sensor 49 and in the lowest area 50 there is a switch-off temperature sensor 3 . Instead of the sensor 3 in the lowermost storage area 50 , a sensor 3 a can be inserted into the cold water discharge line 5 .

In the lowest area 50 , a cold water drain 4 is provided, which is connected via a line 5 to a pump 6 and further via a line 18 to the secondary branch 7 of the secondary heat exchanger 8 of the solar system 51 . On the output side, the secondary branch 7 of the heat exchanger 8 is connected to the hot water line 34 , which in turn opens into a hot water inlet 33 in the central region 41 of the store 1 .

The temperature sensor 35 is located in the hot water line 34 .

The solar system 51 connected to the primary branch 9 of the heat exchanger 8 is constructed as described in the embodiment according to FIG. 1.

The controller 14 , which has the target value transmitter 63 and a differential transmitter 64 , is on the output side with the drive 53 of the pump 6 via a control line 75 , and on the input side with the temperature sensors 3 or 3 a, 13 , 35 and 49 via the Steuerlei lines 74 and 77 , 72 , 76 and 73 connected.

Another water drain 36 is located in the central area 41 of the store 1 , approximately at the level of the hot water inlet 33 of the solar part. This is connected via line 37, the pump 38 and line 39 to the secondary branch 20 of the heat exchanger 21 and further via the hot water line 28 to the hot water inlet 29 in the uppermost region 52 of the store 1 . Approximately in the middle of the upper region 43 there is a switch-on temperature sensor 31 , and approximately at the level of the water drain 36 of the switch-off temperature sensor 44 . This can be replaced by a sensor 44 a in the exhaust line 37 . The temperature sensor 32 is located in the hot water line 28 .

The heat generator connected to the primary branch 22 of the heat exchanger 21 is constructed as described in the embodiment according to FIG. 1.

A controller 60 which is independent of the solar controller 14 and which has a desired value transmitter 61 is on the input side via control lines 82 , 78 , and 79 or 85 with the temperature sensors 32 , 31 and 44 or 44 a, and on the output side via control lines 81 , 83 and 84 connected to the drives 54 , 55 of the pumps 38 , 24 and the actuator 58 of the gas valve 57 .

In the embodiment according to FIG. 2, the heating of the upper 43 and lower 42 storage areas takes place independently of one another.

The lower area 42 is heated via the solar system 51 .

If the setpoint temperature, which represents a maximum temperature, falls below the setpoint value 63 at the temperature sensor 49 and the collector temperature at the sensor 13 is higher than the temperature at the sensor 49 , the process water charging pump 6 begins to deliver. Cold water is drawn off via the cold water drain 4 from the lowest area 50 of the storage 1 and by means of the pump 6 via the lines 5 and 18 , the secondary branch 7 of the heat exchanger 8 , the line 34 and the hot water inlet 33 in the central region 41 of the Memory 1 promoted. Furthermore, the pump 15 of the solar system 51 begins to deliver. The process water flowing in the secondary branch 7 of the heat exchanger 8 is heated by the heating medium flowing in the primary branch 9 of the solar system 51 .

This heating process is ended when a temperature above the temperature specified by the desired value transmitter 63 is detected on the sensor 3 in the lowest area 50 of the memory 1 , or the temperature at the sensor 3 is equal to the collector temperature at the sensor 13 .

Instead of the switch-off sensor 3 in the lowest storage area 50 , a sensor 3 a in the cold water drain line 5 , if possible in the immediate vicinity of the storage 1 , who used the. This sensor 3 a would detect the temperature of the water drawn from the lowest storage area and recognize when the temperature there has reached the desired value.

The control of the pump 6 works as in the embodiment according to FIG. 1, ent either by adjusting the speed or by clocking as a function of the temperature detected on the sensor 35 , the target temperature on the sensor 35 reducing the temperature slightly, for example by 1 to 2K Collector temperature, but the maximum is the temperature set via the set value generator 63 .

If necessary, the sensor 49 can be omitted. Then the pumps 6 and 15 are both switched on and off via the temperature sensor 3 in the lowest storage area. However, this can possibly lead to frequent switching of the pumps 6 , 15 .

The upper storage area 43 is operated like a conventional stratified storage device 1 , independently of the lower storage area 42 and the solar system 51 . If the temperature sensor 31 , approximately in the middle of the upper storage area 43 , falls below the temperature specified by the setpoint value value 61 of the controller 60 by approximately 5-10K, the process water charging pump 18 begins to deliver. Cold water or solar-preheated water is drawn off via the cold water outlet 36 in the central storage area 41 and by means of the pump 38 via the lines 37 and 39 , the secondary branch 20 of the heat exchanger 21 , the line 28 and the hot water inlet 29 into the uppermost area 52 of the memory 1 promoted.

Simultaneously with the pump 38 to go, the heat generator and the heating pump 24 in operation. The Brauchwas water flowing through the secondary branch 20 of the heat exchanger 21 can thus be heated by the flow of heating medium flowing through the primary branch 22 .

The pump 38 is operated as described in the embodiment according to FIG. 1, as a function of the temperature at the sensor 32 and the set temperature set via the set value transmitter 61 .

If the target temperature is reached on sensor 44 , the heating process is ended and pumps 24 and 38 and the heat generator are put out of operation.

Instead of the sensor 44 in the central storage area 41 , a sensor 44 a can be used in the cold water drain line 37 , as close as possible to the store. This sensor would determine the temperature of the water withdrawn from the central storage area and recognize when the temperature there reached the desired value.

The embodiment according to FIG. 3 corresponds in structure and function to that according to FIG. 2.

In addition, there is a three-way switch valve 48 in the hot water supply line 34 , which is connected to the solar controller 14 via a control line 86 . At its third outlet there is a line 47 which opens into the hot water supply line 28 .

Another three-way switch valve 46 , which is connected to the control 60 via a control line 87 , is located in the cold water line 19 . At its third outlet there is a line 45 which opens into the cold water line 5 between the cold water drain 4 and the pump 6 .

The controller 60 has a timer 65 as an additional element. The target value transmitter 61 is connected via control lines 88 , 89 to both the controller 60 and the solar controller 14 .

The lower or upper storage area is heated as described in the embodiment according to FIG. 2.

If the temperature specified by the target value transmitter 61 is exceeded on the temperature sensor 35 , that is, the irradiated solar energy is sufficient to also heat the upper storage area 43 to the target temperature, the three-way switch valve 48 is switched over. The cold water drawn off at the cold water fume cupboard 4 is then pumped by the pump 6 via the lines 5 and 18 , the secondary branch 7 of the heat exchanger 8, the line 34 , the changeover valve 48 and the lines 47 and 28 and via the warm water supply 29 into the uppermost region 52 of memory 1 fed. This makes it possible for the entire contents of the memory 1 to be heated via the solar system 51 .

The second switch valve 46 is controlled by the timer 65 . It is used to heat the entire memory content via the heat exchanger 21 .

For this purpose, if necessary, for example every 24 hours or 48 hours, can be set via the timer 65 , the changeover valve 46 switched and the pumps 24 and 38 and the heat generator started. The pump 38 conveys cold water via the trigger 4 in the lowermost storage area 50 , the lines 5 , 45 , 19 and 39 and the secondary branch 20 of the heat exchanger 21 , where it is heated, and feeds the hot water via the line 28 and the hot water inlet 29 into the top memory area 52 .

A further possibility of controlling the valve 46 arises when the control 14 and 60 are combined . Then, for example, the heating of the entire memory content can take place by the condition "the temperature of the setpoint value 61 not reaching the sensor 49 within 48 hours".

The adaptation of the speed of a multi-stage or a continuously variable pump is shown in FIG. 4. The dependencies are valid for both the pump 6 and which may have the target value generator 61, is set 62 or 63, different values for the pump 38, although T _set.

In all three examples, pump motors that can be operated in stages or continuously can be provided. In the former case, three-stage drives are preferred. When operating at low rigidity, the greater the difference between the temperatures detected by sensors 32 and 32 a, the greater the speed must be.

With continuously variable pump drives, they can be started up accordingly the.

Claims (6)

1. Water heater with a stratified storage tank ( 1 ), a solar collector ( 10 ) and a burner-heated primary heat exchanger ( 26 ), the stratified storage tank ( 1 ) having a cold water inlet ( 2 ) arranged in the lowest area of the stratified storage tank ( 1 ) and a cold water drain ( 4 ), as well as a hot water inlet ( 29 ) and a hot water outlet ( 30 ) arranged in the uppermost area of the stratified storage tank ( 1 ), characterized in that the stratified storage tank ( 1 ) can be heated via two secondary heat exchangers ( 8 , 21 ), a primary branch ( 9 ) of a secondary heat exchanger ( 8 ) from the solar collector ( 10 ) and the primary branch ( 22 ) of the other secondary heat exchanger ( 21 ) from the burner-heated primary heat exchanger ( 26 ). 2. Water heater according to claim 1, characterized in that the secondary branches ( 7 , 20 ) of the secondary heat exchanger ( 8 , 21 ) are connected in series and in a known bypass line ( 5 ) from the cold water drain ( 4 ) to the hot water supply ( 29 ) together with a circulation pump ( 6 ) are arranged. 3. Water heater according to claim 1, characterized in that the stratified storage tank ( 1 ) in its central loading has a with the secondary branch ( 7 ) of the solar collector ( 10 ) associated secondary heat exchanger ( 8 ) connected hot water inlet ( 33 ), and above this middle hot water inlet ( 33 ) another cold water outlet ( 36 ) is seen before, which is connected to the secondary branch ( 20 ) of the primary heat exchanger ( 26 ) heated by the burner, the secondary heat exchanger ( 21 ), which is connected to the top layer of the stratified storage tank ( 1 ) arranged hot water supply ( 29 ) is connected. 4. Water heater according to claim 3 with in the stratified storage tank ( 1 ) to ordered temperature sensors ( 49 , 31 ), characterized in that the lowest temperature sensor ( 49 ) is arranged above the lowest cold water extractor ( 4 ), which switches on the solar collector ( 10 ) assigned circulation pump ( 6 ) controls, and in the lowermost cold water fume cupboard ( 5 ) a further temperature sensor ( 41 ) is arranged, which controls the shutdown of this pump ( 6 ), in the middle supply line ( 34 ) to the middle hot water supply ( 33 ) Preferably, a further temperature sensor ( 35 ) is arranged, which stops the circulation pump ( 6 ) when there is no positive temperature difference between the lowest cold water drain ( 4 ) and the middle hot water inlet ( 33 ). 5. Water heater according to claim 3 or 4, characterized in that a multi-way valve ( 46 , 48 ) is connected to the middle hot water inlet ( 33 ) and to the middle cold water drain ( 36 ), with the middle Cold water drain ( 36 ) connected multi-way valve ( 46 ) has a bypass line ( 45 ) connected to the lower cold water drain ( 4 ) and on the multi-way valve ( 48 ) connected to the central hot water inlet ( 33 ) with the uppermost hot water inlet ( 29 ) connected bypass line ( 47 ) is connected. 6. Hot water heater according to claim 5, in which in the layer memory ( 1 ) in the lowest area and in the uppermost loading area a temperature sensor ( 3 , 31 ) is arranged, characterized in that also in the central region of the layer memory ( 1 ), and in the outlets of the secondary branches ( 7 , 20 ) of the secondary heat exchangers ( 8 , 21 ) a temperature sensor ( 35 , 32 , 44 ) is arranged.