DE19608405A1 - Solar heating system with a hot water storage vessel with frost protection - Google Patents

Abstract

In order to protect the collector (10) in a solar heating system from frost, a pocket of air or gas (25) located in the buffer storage vessel (1) changes places with the water in the collector and its connecting pipes (7,8). Also claimed are a method of operating a heat exchanger in a buffer storage vessel using a domestic hot water heat exchanger whose height in the vessel is adjustable, a method of operating a layered thermal accumulator in which the vertical layering passage is composed of a series of inclined louvres, and a method of operating a solar heating accumulator in which the pipe supplying water to the collector can be connected to different points in the accumulator, so that, when there is little solar gain, at least some of the heated water reaches the temperature required by the user functions. The pocket of air simultaneously serves the function of an expansion vessel for the solar collector and for the heat accumulator. By means of an air bleed pipe (9), part of the return line (7) from the collector empties itself as soon as the recirculating pump is switched off and this provides immediate readiness for a subsequent emptying if required by frosty conditions. If the recirculating pump is switched off when there is no danger of frost (i.e. at temps. above 5 deg. C.) an immediate complete emptying of the water from the collector and return line is prevented by means of a siphon (13) and a non-return valve (11). Filling of the collector with air for frost protection is achieved by means of a thermostatic valve (12) which permits the emptying of the collector by opening in frosty conditions. The water pressure in the collector supply pipe (8) above and below the storage vessel level (24) can be monitored by means of a pressure difference switch (15) giving an indication of the absence of water in the collector and the return line. The differential pressure sensor can also sense the level of the water in the storage vessel and hence detect water loss and can, because of its high sensitivity, measure the velocity and hence flow rate of the water by measuring the differential pressure arising from the hydrodynamic resistance of the pipe. Using the flow rate thus measured and the temperatures measured in the supply and return pipes, the amount of heat collected can be determined. The differential pressure switch can also sense the presence of a vacuum caused by high temp. in the collector by detecting fluctuations in water flow rate. A temperature-controlled valve reacting to the temp. in the collector can be used to empty the collector to prevent boiling.

Description

State of the art

When operating a solar system, the fuse of the solar collector provides against frost damage is one of the problems. The heat transfer medium is common prove out of water.

To operate domestic water heating with solar energy are important So far, three methods have been known for frost protection:

1. Heat transfer medium with antifreeze additive

An antifreeze is added to the water as a heat transfer medium

advantage

Frost protection problem is reliably solved.

disadvantage

• - The heat transfer medium must pass through a heat exchanger will. An independent cycle is created with Pressure relief valve and expansion tank from which follows:
• - Additional costs through additional heat exchanger, frost protection medium and additional expansion tank.
• - Poor efficiency due to additional heat build-up shear as well as deterioration of heat transport ability by adding antifreeze.

2. The heat transfer medium is process water - frost protection by emptying

The heat transfer hot water is used when there is a risk of frost 5-way valve drained from the solar collector.

advantages

• - Good efficiency

disadvantage

• - Expensive and complicated anti-freeze system with failure-prone (e.g. power failure) 5-way valve
• - Only expensive vacuum collectors are suitable for this
• - Use only for process water as a storage medium
• - Increased risk of corrosion of the solar collector by aggres sive process water

3. The heat transfer medium is process water - frost protection through heating

The heat transfer medium is used when there is a risk of frost Circulation pump tempered to approx. + 5 ° C. This type of frost protection is used for a vacuum collector with a dry flange on the process water manifold applied (Siemens).

If there is frost damage, a piece of copper cable must be replaced will.  

advantages

• - In principle good efficiency
• - Simple system

disadvantage

• - Can only be used for expensive vacuum collectors
• - deterioration in efficiency due to dry Flange the vacuum tubes to the manifold
• - Damage to the system occurs in the event of frost and power failure as well as plant failure.

Regarding the heat storage and its stratification behavior are ver different plants known.

For example, systems are known which are used to achieve good stratification behavior at least one stratification channel arranged over the entire storage height have in which vertical outlet holes are made. However, the number and cross section of these outlet holes are limited because here in addition to the desired height-related exit of the to be stored Water also unwanted mixing takes place at all other holes Find.

Therefore, a height-related exit of the water to be stored is via a larger height zone distributed and therefore not precisely executable.

Regarding the heating of process water and its temperature setting Plants are known in which the domestic water by means of a total storage height of a buffer storage arranged heat exchanger is heated.

In the classic case, however, hot process water is extracted directly from a storage tank filled with process water.

The desired hot water temperature is determined by adding cold water reached with the help of a regulated three-way valve.

Because in a solar system the storage tank is often heated above 60 ° C calcification of the system parts can occur. Plant failures and Repairs are the result.  

Advantages of the invention

The system described here has set itself the task, while maintaining simple and therefore cheaper flat plate collectors Increasing efficiency in solar energy generation while at the same time Reduction of system components.

This is achieved in that the safe and damage-free operation of the Facility with regard to frost damage is guaranteed, although the heat inert water is not mixed with antifreeze. As frost protection serves to drain the heat transfer water from all endangered systems share (solar collector and supply and return lines).

This arrangement enables the otherwise customary independent solar circuit omitted.

An air or gas bubble ( 25 ) in the upper part of the buffer storage ( 1 ) serves as an expansion element for the storage and solar water.

If there is a risk of frost and the associated emptying of those at risk of frost Solar components exchange part of this gas with water in the solar components. The emptying of the solar components can be done in one closed system.

Since it is advantageous for hygienic reasons, the process water is over Heating a heat exchanger can be used as a buffer storage classic pressurized as well as an open storage (e.g. unpressurized plastic storage) can be used.

This results in the following special features:

• - Better efficiency of the solar system by eliminating a heat rope shear and the antifreeze in the heat transfer medium.
• - Safe frost protection of the solar system. The emptying of the solar collector including its supply and discharge takes place without active intervention electrical system components.
• - Saving of antifreeze and a pressure relief valve.
• - Saving of one or two expansion vessels (solar circuit and if necessary. Buffer tank) → Fewer individual components as well as simple and cost-effective installation of the system.
• - Saving an expensive coating of the heat accumulator in the form of V2A or enamel (no hot water tank).
• - Additional frost protection in the event of a system failure by monitoring the ord proper emptying of the solar components by the control unit and Heating the solar collector to + 5 ° C using a solar pump.
• - Use of normal flat-plate collectors, which empty themselves completely let (inexpensive collectors).
• - Solar storage can be used as a universal buffer storage z. B. for heating integration can be used (without additional expansion vessel).  
• - An open, unpressurized storage tank can be used up to a system height of approx. 7m, since there is negative pressure in the solar collector.
  A vacuum is created from a water column of 10 m.
  However, this theoretical usable height cannot be used due to the associated earlier boiling point of the water in the solar collector.
  A pressure accumulator should therefore be used for larger system heights.

Furthermore, due to a special design of the domestic hot water exchangers the hot water temperature control already pre-stored taken. This is achieved by placing the domestic water heat exchanger in the buffer storage is arranged adjustable in height over the entire storage height.

The height adjustment of the heat exchanger is based on the temperature of the hot water at the outlet of the heat exchanger (top edge of the heat exchangers).

This means that there is little calcification of hot water in the heat exchanger at the same time high possible storage temperature and good stratification of the memory can be reached.

Another heat exchanger can be used to integrate a heating system be attached.

If the storage water is fed directly into the heating, it is sufficient to Suction point of the flow line on the height-adjustable hot water heat rope shear to attach.

This results in the following special features:

• - Consumption-independent (regulated) hot water temperature at the outlet of the Heat exchanger.
• - Optimal use of the heat storage capacity of the buffer storage thanks to the height-adjustable hot water heat exchanger in a flat design as well as high possible storage temperature - with pressure storage up to 110 ° C.
• - Minimal calcification of the hot water heat exchanger and the hot water cables. Set hot water temperature = max. Occurring in the heat exchanger temperature.
• - Good stratification properties of the buffer storage.
• - Use of pressureless plastic buffer stores possible.
• - The initial temperature for hot water and heating flow temperature can be controlled with the same servomotor for a common setpoint.
• - The domestic water heat exchanger can be wound bivilar to turn to avoid moments in the heat exchanger when changing the amount of hot water.

The supply line to the solar collector is in terms of its suction location Buffer memory switchable. Switching the currently valid intake height is triggered by the height-adjustable heat exchanger.

This results in the following special features:

• - At least a minimum amount in case of bad solar radiation of the storage water to the full target hot water temperature the suction point is raised.
• - The exact suction height can be preset (69) in order to adapt the minimum amount of heat to individual consumer requirements. If the solar feed is insufficient, the amount of heat that is still missing is heated up by an external boiler ( 34 ) or by an installed electrical heating element ( 42 ). In this case, the same adaptive suction point applies as for the solar feed.
• - If the minimum daily heat requirement is covered, the suction point becomes after switched at the bottom.
• - Once the heat exchanger has reached the bottom of the buffer tank, to protect the process water from overtemperature (and thus also calc of the heat exchanger and the pipes) the suction point for the Solar collector installed above the heat exchanger.

To further improve the layering properties of the memory, that from the solar collector and if necessary. from the heating circuit to the heat water flowing back into a kind of vertical stratification channel initiated.

This stratification channel consists of one another arranged at an angle slats overlapping in height. So that the stratification behavior of the storage water used to cover the many over the entire height arranged large cross-sectional outlet openings in the stratification channel close.

This results in the following special features:

• - In contrast to previously known vertically in the stratification channel brought exit holes which have no such locking behavior sen and are therefore limited in the outlet cross-section, is a precise height-related exit point of the from the solar collector or Heating return flowing water reached.
• - The feed point of this return water in the lamellae The stratification channel can be from above, the middle or from below.
• - The layering channel is flexible and can be pushed together in length and can therefore be inserted through a side flange into a metal store be introduced.

Further advantages and more detailed descriptions result from the following ing description of the exemplary embodiments and from the dependent Claims.

drawings

Fig. 1 shows the overall picture of a solar system, the buffer memory is equipped with a height-adjustable hot water heat exchanger.

Fig. 2a shows a sectional view of a buffer memory, Fig. 2b shows a top view of a winding position of the heat exchanger.

Fig. 3a shows various possible temperature stratification curves of this memory via the memory level.

FIG. 3b illustrates a detail drawing the trajectory of the heat exchanger tube.

FIG. 4a shows a further variant of a stratification channel with lamellae (as shown in FIG. 5) in a detailed drawing.

FIG. 4b shows a detailed drawing of the operation of the slider mechanism of the heat exchanger dependent suction for the solar collector.

Fig. 5 shows a solar system with its own auxiliary pump for refilling higher-lying solar collectors after a Frostent emptying. Furthermore, a buffer storage with an external heat exchanger and the integration of a heating system is shown here.

Description of the embodiments

In Fig. 1 the basic operation of the solar system is shown.

The circulation pump of the solar circuit ( 16 ) has a large performance range in FIG. 1. When restarting after a frost phase, the delivery height must be such that it extends to the uppermost part of the system (here backflow preventer 11 ).

In addition, the flow rate must be sufficient to prevent rising air bubbles in the return line ( 7 ) during the filling phase.

After completing the filling phase, the pump delivery rate can be reduced to a norma les circulation level can be reduced. Modern electronically controlled circulation pumps are able to meet such requirements.  

The water from the heat accumulator ( 1 ) (closed or open accumulator) flows directly through the solar collector ( 10 ), driven by a pump ( 16 ).

The supply line to the solar collector is represented by line ( 8 ), the return line by line ( 7 ). The function of the expansion vessel for the solar collector and the heat accumulator is taken over by an air bubble ( 25 ) or nitrogen (better corrosion protection) that collects in the upper part of the buffer accumulator ( 1 ). A siphon ( 13 ) prevents the air bubble ( 25 ) from rising into the solar collector ( 10 ) via the line ( 7 ) and the backflow preventer ( 11 ).

After the feed pump ( 16 ) has been switched off, the water circuit comes to a standstill.

The water in the riser ( 7 ) slowly empties below the siphon ( 13 ) to the level of the water in the reservoir ( 20 ), with the necessary air flowing in via the line ( 9 ). However, the riser ( 7 ) cannot empty because no air can enter this line section due to the siphon ( 13 ).

However, this short, emptied pipe section (approx. 20 cm high) is sufficient to create an imbalance in the water circuit of the solar collector ( 10 ) and its feed lines ( 7 and 8 ).

Since the backflow preventer ( 11 ) and the valve ( 12 ) are also closed at temperatures above + 5 ° C, this imbalance cannot discharge.

Since there is no risk of frost in the summer, there is no need drain the water in the solar collector.

The solar collector and its supply lines remain filled. When the feed pump ( 16 ) is switched on again, the last section below the siphon ( 13 ) fills up quickly and the system is immediately ready for operation again.

However, if the outside temperature drops further than approx. + 5 ° C after the system has been switched off (e.g. overnight), the thermostatic valve ( 12 ) opens (type such as on every radiator in the frost position). Now the water cycle of the solar collector begins to move backwards, driven by the already existing and described imbalance.

This water now flows through the collector ( 10 ) via the riser ( 8 ) and the switched-off feed pump ( 16 ) back into the buffer tank ( 1 ). Thus, the solar collector ( 10 ) and its supply lines ( 7 and 8 ) are free of water and thus protected against frost.

The thermostatic valve can be replaced. also be dispensed with. However, this means that the solar collector is emptied each time the feed pump is switched off. The backflow preventer ( 11 ) can also be placed in the vicinity of the pump or the accumulator.

For safety reasons, a differential pressure sensor ( 15 ), which checks the riser ( 8 ) for freedom from water, can monitor this drainage function together with an outside temperature sensor.

If for some reason this emptying does not take place, it will the feed pump switched on and with the help of a temperature sensor in the Solar collector lowers the water temperature of the solar system to approx. + 5 ° C applies.

The differential pressure sensor measures the differential pressure between lines ( 14 ) and ( 17 ). If the pipes are filled with water on both sides and the feed pump is switched off, the differential pressure is zero. However, if line ( 8 ) is emptied, the differential pressure sensor sees a higher water column on line ( 14 ) and thus a relatively higher pressure than on line ( 17 ).

The level of the differential pressure is proportional to the level ( 24 ) of the buffer tank. The differential pressure sensor ( 15 ) thus simultaneously enables the measurement of the current size of the air bubble ( 25 ) and thus also provides an indication of a possible water loss in the system.

When filling the system for the first time, this differential pressure sensor ( 15 ) can help the installer with the correct filling quantity of the storage tank.

This high differential pressure sensor is also suitable sensitivity to measure the water flow rate and thus to measure the amount of water by measuring the flow resistance created pressure difference within a defined pipe section measures.

In connection with the temperature measurement of the outgoing in line ( 8 ) and in line ( 7 ) returning solar water, the amount of heat obtained by the collector can be detected.

Expensive heat meters can thus be saved.

Fig. 2a shows a sectional view of a buffer memory, Fig. 2b shows a top view of a winding position of the heat exchanger.

This buffer storage tank has a domestic water heat exchanger which is connected to the total storage height is arranged adjustable in height.

The height adjustment of the heat exchanger is determined with the aid of a temperature sensor ( 22 ) which is attached to the hot water outlet of the heat exchanger ( 2 ).

The supply lines to the heat exchanger ( 41 ) consist of flexible pipes, the hot water outlet side being thermally insulated.

Since these supply lines are attached to the bottom of the heat exchanger, there are no thermal problems for the pipe material.

If the storage water is fed directly into the heating system, a third line to the heat exchanger and the suction point of the Heating flow at the upper edge of the height-adjustable hot water heat exchanger attached.  

In order to achieve good stratification properties of the storage tank, any hot water feed into the storage tank is introduced via a type of vertical stratification channel ( 46 ), which consists of slats ( 47 ) which are arranged at an angle and one above the other and which overlap in height.

Such a stratification channel ( 46 ) for the returning solar water ( 7 ) can be seen in FIGS . 1 and 2a. In Fig. 2b, a further such layering channel (53) is located for the heating return (30).

In Fig. 2b, the course of a winding layer is shown. From the water inlet ( 58 ) a spiral winding is shown towards the center. There the winding direction ( 59 ) rotates and finally ends again on the outside ( 61 ) in order to dive from there into the winding position (below 58 ) that begins below. This civil winding type prevents torques on the heat exchanger when there are changes in the amount of hot water.

By means of a temperature sensor ( 22 ), the height setting of the heat exchanger can be controlled so that the hot water temperature at the outlet of the hot water heat exchanger ( 2 ) is always a predetermined temperature value z. B. has 45 ° C. This setpoint is adaptive and is specified by the control unit.

If the outlet temperature of the Heat exchanger sink, this can be done by raising the Process water heat exchanger are regulated in hotter storage water. At the outlet of the heat exchanger there is therefore a constant quantity-independent Domestic hot water temperature available.

Using suitable sensors such. B. a permanent magnet on the rotating threaded rod ( 40 ) and a reed contact, the height of the heat exchanger and the lower and upper stop can be monitored. The stop detection is carried out by lifting the rotating permanent magnet through the threaded rod ( 40 ) at the lower stop or by lifting using the threaded part for the heat exchanger support ( 62 ). This causes an interruption of the speed signal at the reed contact.

The exact height position of the heat exchanger can always be recognized with the speed signal. This can be used in connection with the temperature detection on the heat exchanger ( 22 ) and on the top of the storage tank (temp. Sensor 21 ) for the approximate determination of the storage volume.

The suspension and height adjustment of the heat exchanger is also possible a cable is conceivable on which the heat exchanger is suspended (e.g. on three ropes).  

The characteristic curves shown in FIG. 3a show different theoretically possible layer temperatures over the storage height of the buffer storage.

Characteristic curve 71 shows the minimum storage tank temperature at which the heat exchanger is just still able to supply the required process water temperature.

Characteristic curve 72 shows the minimum daily heat requirement loaded. When the storage tank is charged further, the suction point of the solar collector is switched from opening ( 45 ) to opening ( 43 ).

Characteristic curve ( 73 ) shows the heat exchanger in the middle height position (as shown in FIGS. 1 and 2a), the upper half of the storage unit being shown here with maximum thermal energy.

Characteristic curve ( 74 ) shows the maximum possible charge of the storage. It can clearly be seen here that the heat exchanger in the lowest area of the storage tank is protected against excess temperature and, as usual, supplies the required hot water temperature. At this point at the latest, the solar system is switched off.

In order to prevent evaporation of the now standing water in the solar collector, the temperature of the solar collector can be emptied depending on the solar collector temperature using a temperature-dependent valve (see Fig. 5/71).

In Fig. 3b a possible winding arrangement of the heat exchanger (2) is shown in an enlarged sectional drawing. The order of the digits in the pipes shown corresponds to the order of the ge wrapped pipes seen from the exit of the heat exchanger. It becomes clear that this is a kind of interlocking winding sequence.

This means that the stratification of the storage tank is static a pure counterflow heat exchanger.

Fig. 4a shows a comparison with FIG. 1 and 2 modified embodiment of a vertical stratification duct (46).

Applied while Fig. 1 and 2, an integrally in the corner of a rectangular memory stratification duct constitute, in this case a free-standing variant is shown a lamination channel.

The individual fins ( 47 ) are made from round conical cylinders. These slats can e.g. B. connected to each other via thin chains ( 50 ).

The layering channel formed in this way can be inserted through the Flange opening of a steel accumulator telescoped or be bent.

In order to achieve permanent erection, the stratification channel is equipped with a floating body ( 49 ) at the top.

The feed point of the stratification channel ( 51 ) can be at the top, in the middle (see Fig. 4a) or from below as shown in Fig. 5/53.

FIG. 4b shows a relative to its Ansaugortes switchable supply line to the solar collector.

The applicable suction height is switched over by the height-adjustable heat exchanger, which pushes the drivers ( 70 ) up and down to actuate the respective change-over slide.

When the solar radiation is low, the suction point ( 45 ) is raised. This switchover is activated by the heat exchanger that is started up.

A spring ( 66 ) pulls up a slide ( 63 ) and closes the two lower suction types ( 43 , 44 ). As long as the heat exchanger is not positioned high enough, a weight ( 67 ) counteracts the spring force ( 66 ) and prevents the two lower suction points ( 43 , 44 ) from closing. Only when the heat exchanger ( 2 ) has been raised sufficiently does it push the weight ( 67 ) up and allow the spring ( 66 ) to pull the slide ( 63 ) up. Only now the upper intake (45) is activated by the closure of the two lower großquerschnitti gen intake (43,44).

With a lockable adjustment ( 69 ) of the slide ( 63 ) with respect to a plate which contains the suction opening ( 68 ), an adaptive suction height adjustment is achieved in order to adapt the minimum amount of heat to the individual consumer requirement.

If the solar feed is insufficient, the built-in electric heating element ( 42 ) supplies the missing heat requirement. This heating element ( 42 ) uses the same opening ( 45 ) during its charging for its circulating flow ( 19 ).

If the minimum daily heat requirement is covered, the suction point is switched to the very bottom ( 43 ) by lowering the heat exchanger ( 2 ).

If the heat exchanger has reached the bottom of the buffer storage in the further course of charging, the lower suction point ( 43 ) for the solar collector is closed by means of the lowering of the slide ( 64 ) and opened above the heat exchanger ( 44 ).

After the heat exchanger is raised again, the spring ( 65 ) pulls the slide ( 64 ) back into its raised, rest position.

In Fig. 5 is finally a solar system with an additional auxiliary pump ( 27 ) for refilling higher-lying solar collectors after a frost drain is shown.

A backflow preventer ( 26 ) prevents the water conveyed by the pump ( 16 ) from flowing back in normal operation.

A three-way switch valve ( 38 ) allows external switching of the suction point to cover the minimum daily requirement by the solar collector.

Furthermore, a buffer memory with two stratification channels ( 46 and 53 ) already shown in FIG. 4a is shown here.

The hot water heat exchanger ( 2 ) is attached externally, with its own circulation pump ( 37 ) regulating to a constant hot water temperature. The return line ( 30 ) is returned via a stratification channel ( 53 ).

A heater connection is also shown. A three-way switch valve ( 33 ) can be used to switch between a supply from the buffer tank ( 1 ) or a boiler ( 34 ).

With the help of a circulation pump ( 35 ), the buffer tank (I) can be loaded from the boiler ( 34 ).

A circulation pump ( 28 ) serves as a heating circulation pump while a four-way control valve ( 32 ) regulates the flow temperature.

Reference list

1 buffer tank (no enamel or stainless steel) filled with heating water
2 heat exchangers (WT) for domestic water heating
3 Domestic hot water supply cold
4 Hot water outlet warm
5 heat exchanger supports
6 frost limit
7 Return line from the solar collector
8 Supply line to the solar collector
9 Air line to empty solar collector
10 solar collector
11 non-return valve (spring-loaded)
12 Temperature-dependent valve (frost monitor that opens at temp. <+ 5 ° C)
13 Syfon prevents emptying of the return line ( 7 )
14 Upper supply line to the differential pressure sensor
15 differential pressure sensor
16 Circulation pump for solar collector
17 Lower supply line to the differential pressure sensor
18 Switching the suction height for the solar collector
19 Flow pattern when operating additional electrical heating
20 line section between Syfon ( 13 ) and height of water surface ( 24 )
21 Temperature sensor on the top edge of the storage water
22 Temperature sensor for hot water outlet temperature (upper edge WT)
23 Stratification-dependent exit point of the warm solar collector water
24 water levels in the buffer tank
25 Air or nitrogen bubble as a replacement for the expansion tank
26 non-return valve (spring-loaded) for additional pump
27 Additional feed pump for solar collector filling
28 Heating circulation pump
29 tapered tee
30 heating return
31 heating flow
32 Four-way mixing valve for flow temperature control
33 Three-way diverter valve for optional supply from the storage tank / boiler
34 boilers
35 Circulation pump for storage tank charging by the boiler
36 backflow preventer with heating integration
37 Circulation pump for external process water heat exchanger
38 Three-way changeover valve for changing the suction level in the heat accumulator
39 Motorized drive for height adjustment of the heat exchanger
40 threaded rod for height adjustable heat exchanger
41 spiral supply and return lines of the height-adjustable heat exchanger
42 Additional electric heater
43 suction opening at the bottom (normal suction point)
44 suction opening above the heat exchanger (WT protection)
45 suction opening at the top (for loading the minimum daily requirement)
46 stratification channel for correct storage of the solar collector water
47 lamella of the stratification channel
48 lens
49 floats to hold up the stratification channel
50 holders for slats (e.g. chains or trellis)
51 Entry point of the return
52 Reverse louvre mounted below the entry point
53 stratification channel for correct storage of the heating return
54 Cold hot water supply
55 consumers e.g. B. shower facility
56 DHW main
57 Cold water main
58 Water entering the heat exchanger tube
59 reversing loop (change of direction)
60 Returning heat exchanger tube
61 End of this winding level and transition to the winding level below
62 threaded part for heat exchanger support
63 Slider 1 for shutting off the lower part with a minimum charge
64 Slider 2 for shut-off at the bottom with overtemperature protection of the WT
65 tension spring for holding up slide 2 ( 64 )
66 Tension spring to hold slide 1 up ( 63 )
67 Weight for pushing down slide 1 (raised by the heat exchanger)
68 Suction opening adjustable in relation to slide 1
69 Adjustable locking device for adaptive minimum charging
70 drivers for actuating the slide through the heat exchanger
71 Temperature-dependent valve with external temperature sensor (opens at adjustable temperature greater than + 70 to 110 ° C)

Claims (24)

1. Solar system with hot water tank, characterized in that for the purpose of frost protection of the solar collector, an air or gas bubble ( 25 ) located in the buffer store ( 1 ) exchanges its place with the water in the solar collector and its supply lines. 2. The method according to claim 1, characterized in that this air or gas bubble ( 25 ) simultaneously takes over the function of the expansion vessel for the solar collector as for the heat accumulator. 3. The method according to claim 1, characterized in that with the help of a ventilation line ( 9 ) a part of the solar collector return line ( 20 ) emptied immediately after switching off the circulation pump ( 16 ) and thus the preparation prepares for later frost-related emptying. 4. The method according to claim 1, characterized in that with a shutdown of the feed pump ( 15 ) at no risk of frost (temperature greater than + 5 ° C) with the aid of a siphon ( 13 ) and a backflow preventer ( 11 ) an immediate emptying of the water from the Return line ( 7 ) and the solar collector ( 10 ) can be prevented. 5. The method according to claim 1, characterized in that the filling of the solar collector with air for the purpose of frost protection depending on the outside temperature with the help of a thermostatic valve ( 12 ) can be done, which enables emptying of the collector by opening in the event of frost. 6. The method according to claim 1, characterized in that by means of a differential pressure sensor (15) the water pressure lower in the collector lead (8) and controlled above the storage level (24) and therefore also the solar collector (10) and the return line (7) can be checked for water freedom. 7. The method according to claim 6, characterized in that this differential pressure sensor can also detect the water level of the reservoir ( 24 ) and thus a possible water loss of the system ( 1 ). 8. The method according to claim 6, characterized in that this Differential pressure sensor due to its high sensitivity also the water Measure the flow rate and thus the amount of water flowing through can by the pressure created by the flow resistance measures the difference within a defined pipe section.   9. The method according to claim 8, characterized in that in connection with the temperature measurement of the outgoing in line ( 8 ) and in line ( 7 ) returning solar water so that the amount of heat obtained by the collector can be detected. 10. The method according to claim 6, characterized in that this Differential pressure sensor through the detection of flow rate fluctuations also the formation of vacuum due to high temperature and recognizes low absolute pressure in the solar collector and by increasing the Pump performance eliminated. 11. The method according to claim 1, characterized in that with the aid of a temperature-dependent valve ( 71 ) depending on the solar collector temperature, a water drainage of the solar collector can be carried out to prevent boiling of the standing water in the collector. 12. Method for operating a heat exchanger in a buffer store, characterized in that the domestic water heat exchanger in the buffer memory is arranged adjustable in height. 13. The method according to claim 12, characterized in that the heights adjustment of the heat exchanger based on the temperature of the domestic water Output of the heat exchanger is oriented so that a consumption-independent dependent (regulated) hot water temperature arises. 14. The method according to claim 12, characterized in that when the storage water is fed directly into the heating system, the suction point of the flow line ( 31 ) is attached to the height-adjustable process water heat exchanger, whereby the output temperature for process water and heating connection with a common setpoint with the same servomotor ( 39 ) can be regulated. 15. The method according to claim 12, characterized in that for the binding of a heating system with a separate heating circuit, a further heat exchanger can be attached to the heat exchanger carrier ( 5 ). 16. The method according to claim 2, characterized in that the custom water heat exchanger ( 2 ) can be wound bivilar to compensate torques in the heat exchanger due to changes in the amount of hot water. 17. A method of operating a stratified heat accumulator which is provided with a vertical stratification channel ( 46 ), which extends upwards in a heat accumulator ( 1 ), characterized in that for better stratification of this memory, this stratification channel consists of diagonally arranged, height-related overlapping slats exists to close the large cross-sectional outlet openings in the stratification channel with respect to their flow behavior according to the law of gravity. 18. The method according to claim 17, characterized in that the feed point of this stratification channel from above, in the middle or from below can. 19. The method according to claim 17, characterized in that the layer device channel ( 46 , 53 ) is flexible and collapsible in length, so that it can also be brought into a metal store through a side flange. 20. Method for operating a solar storage in which the storage water feeds the solar collector directly, characterized in that the Supply line to the solar collector can be switched with regard to its suction location, to in the case of low solar radiation at least a minimum amount of To heat the storage water to the full target hot water temperature. 21. The method according to claim 1 and 20, characterized in that a switchover of the respectively valid suction height is carried out by the height-adjustable heat exchanger ( 2 ). 22. The method according to claim 21, characterized in that the exact Suction height for the daily minimum amount of heat is adaptively adjustable (69) in order to adapt this minimum amount of heat to individual consumer needs fit. 23. The method according to claim 22, characterized in that in the case of post-heating by a built-in electric heating element ( 42 ) the same preset suction point ( 69 ) is used as in the solar feed. 24. The method according to claim 1, characterized in that when the heat exchanger is reached at the bottom of the buffer store, the suction point for the solar collector is placed from the bottom to a point above the heat exchanger ( 44 ) in order to protect the heat exchanger and its supply lines from excess temperature and to be able to maintain the desired hot water temperature and to prevent the formation of limescale in the hot water heat exchanger.