DE29806464U1 - Water storage, especially for a central heating system with a solar collector - Google Patents

Description

Water storage tank, especially for a central heating system with solar collector

The invention relates to a water storage tank, in particular for a central heating system with solar collector, according to the preamble of claim 1.

In a solar system with an external heat exchanger, the problem is how to optimally feed the heated water into a storage tank.

In order to avoid thermal mixing of the storage water, the temperature of the water introduced should correspond as closely as possible to the temperature of the storage layer into which the water is introduced. The more precisely the supply water is deposited, the lower the temperature losses caused by mixing.

A layered buffer storage tank with a charging machine is known in which the mouth of a charging pipe is swiveled by means of a thermal drive into the temperature layer that corresponds to the solar flow temperature.

The thermal drive is carried out using a temperature difference control. Its storage sensor is located at the mouth of the charging pipe.

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In practice, it has been found that the loading pipe moves back and forth like a stirring rod and thus prevents or destroys the desired calm stratification of the water to be loaded.

The nozzle-shaped opening of the charging pipe is also not suitable for ensuring a smooth stratification of the water flowing into the storage tank.

EP 0 384 423 Bl describes a (domestic) hot water storage tank with a hot water supply pipe arranged vertically therein, which is provided with outlets arranged at intervals one above the other, in/on which flap valves are arranged that open into the storage space. The flap valves consist of an elastomer and are designed as one-piece plate-shaped check valves.

As long as the water acting on the outside of the flap has a higher density than the water on the inside, the differential pressure acting on the flap will press the flap with its edge area against the valve seat.

When the temperature and thus density of the water on both sides of the valve flap is unequal, the sealing pressure acting on the valve flap is removed and the stored heated water should open the flap with its kinetic energy so that the heated water can flow into the storage tank. The water flowing in through the supply pipe is strongly swirled due to the 90° deflection in the area of the outlets, which creates uncontrollable kinetic energy. This swirling means that the flap opening is largely dependent on the flow and not on the temperature.

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It has also been shown that the valve flaps mentioned are relatively heavy and difficult to move. Optimal stratified storage does not seem possible in this way,

What the above-mentioned storage systems have in common is that a defined spatial separation between the cold and the warm areas is either not guaranteed at all or at least not optimally guaranteed.

If there is no optimal stratification of the water at different temperatures but rather a thorough mixing, then on the one hand the heat supplied by the boiler cannot be completely discharged and on the other hand solar heat can only be used at the highest temperatures.

The task still remains to describe a heat storage system in which the charging process is assigned to the isothermal layer of the storage system.

This object is achieved on the basis of the features mentioned in the main claim. Preferred embodiments are characterized in the subclaims.

The storage tank according to the invention is a so-called shunting storage tank; during the charging process, the flow of the water entering from the solar collector heat exchanger is diverted to the horizontal using a honeycomb plate and laminarized, i.e. eddies are suppressed; the flow is calmed overall. In this way, gravity is primarily effective, which means that colder, specifically heavier water is in the lower area and warmer, specifically lighter water is in the upper area of the

container. For this purpose, pivoting scales on a flexible scale plate open slots at the height at which the water has approximately the same temperature on both sides of the scale plate, thus achieving the desired calm stratification during the loading process. The flexibly deflectable scales represent hydraulic rectifiers with a directed valve effect.

A scale sheet made of stainless steel foil has proven to be advantageous. But various plastic foils also have an excellent ventilating effect even at the slightest temperature difference.

On the side of the various return flows, the calm stratification is further supported by a plate arranged transversely in the lower part of the tank, which is provided with openings and a baffle plate. Only the difference between the currents formed by the forward and return flows passes through the opening. The baffle plate largely prevents the water rising into the other tank from swirling.

A diffuser attached to the primary boiler flow inlet ensures that the warm flow water is fed into the storage tank in layers. Preferably, a gas separator is installed between the flow inlet and the diffuser.

A dirt separator in the lower part of the tank ensures that the dirt particles circulating in the heating system are retained.

A magnetite separator can be provided for the separation of ferromagnetic particles.

Temperature sensors installed at different heights inside the tank ensure that a charging process only takes place when charging is required and correspondingly warmer water is available from the solar system.

An embodiment of the invention is explained with reference to the accompanying drawings.

Fig. 1 shows the circuit diagram of a heating system with solar collector and a water storage tank according to the invention (“shunting storage tank”);

Fig. 2a - d show different views of the water reservoir according to the invention;

Fig. 3a - f show details of the scale plate that characterizes the water reservoir.

The water storage tank shown in longitudinal section in Fig. 2a (“layered storage tank”, “buffer storage tank”, “shunting storage tank”) 2 consists of a cylindrical vessel 4, which is preferably arranged in an upright position, which is covered with thermal insulation (not shown) and which is provided with feet 6 for stationary installation.

On the left in the picture you can see two pipe sockets 8, 10 for connecting the flow and return of a heat source (e.g. a gas boiler). On the right in the picture you can see two further pipe sockets 12, 14 as connections for the flow and return of consumers (e.g. radiator circuits and decentralized heat exchangers, see also Fig. 1). The secondary side flow socket 12 ends at the top

angled in the upper part of the tank 4. In addition, several pipe sockets 62, 64, 66, 68, 70, 72 and 74 are arranged on the storage tank for attaching temperature sensors.

At the side of the container 4 there is a honeycomb plate 16 arranged essentially vertically. On the honeycomb plate is a flexible scale plate 18, i.e. a sheet of sheet metal or plastic provided with pivoting scales 20 for opening or closing slots in the surface of the honeycomb plate 16 as required (Fig. 3). At the lower end a pipe socket 34, which serves as the supply line for a solar system 26, opens into the separated area 24 of the container 4 remaining behind the scale plate 18.

The water fed in from the solar collector flow line via the pipe socket can reach the further space 32 of the container 4 at each pivoting scale 20.

For thermodynamic reasons, the water fed in from the solar system 26 (solar collector 28, heat exchanger 30) passes through the flexible scale plate 18 only at the height at which the temperature of the fed-in water is equal to the respective layer temperature of the other container 32. In this way, turbulence of the water in the container 4 is largely avoided.

The flow of the solar system 26 into the storage tank (shunting storage tank) 2 takes place through a pipe socket 34 in the lower part of the area 24 of the container 4 separated by the scale plate 18.

A gas separator 38 is connected to the end of the heating flow 8 that extends into the container 4. At the upper end of the gas separator 38 there is a vent pipe 40. At the lower end of the gas separator 38 there is a diffuser 42 attached as an outlet.

The primary side 10 and the secondary side return pipe 14 are arranged on opposite sides at the bottom of the tank 4. Just above these pipe pipes 10, 14, the tank 4 is equipped with a transverse, i.e. horizontally arranged plate 36. In its center, this plate 36 has an opening 44, which is opposed by a baffle plate 46. This calms the water flowing between the secondary side 14 and the primary side return 10. Only the difference in the volume flows resulting from the primary and secondary side circuits passes through the opening 44 in the plate 36.

At its lower end, the storage container 4 has a dirt separator 48. At the lowest point of the container 4 there is a drain opening 50. The dirt separator 48 can be combined with one (or more) magnetite separators 52 for separating rust particles and similar ferromagnetic particles.

Ferromagnetic particles collect on the sleeves of the magnetite separators designed as "magnetic candles". If the magnetic candles, which are accessible from the outside, are removed, the magnetic sludge collected on the sleeves falls to the ground and can be disposed of through the emptying opening 50.

The water storage tank (shunting tank) 2 shown in Fig. 2 serves not only as a buffer tank for

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the heating system, but at the same time it represents a so-called "hydraulic switch". The water storage tank (shunting tank) 2 thus serves to decouple boiler circuits (in general: from heat sources, regardless of whether boilers, solar collectors and/or heat pumps serve as heat sources), on the one hand, and downstream consumers (e.g. radiators 54 and domestic hot water heat exchangers 56), on the other. A charge takes place when the sum of the incoming heat quantities generated is greater than the sum of the heat quantities consumed.

The volume flow flowing vertically in the tank 4 is equal to the difference between the volume flows offered by the heat sources (boiler, solar system, etc.) and those taken from the heating circuits. If the volume flow taken from the radiator circuits is greater than that offered by the boiler 58 and the solar system 26, return water flows through the storage tank 2, which acts as a hydraulic switch, from the secondary return 14 directly towards the flow 12 of the heating (radiator) circuits and mixes with the boiler flow water 8.

If, however, the volume flow taken from the radiator circuits is smaller than that of the boiler 58 and the

Heat exchanger 30 of the solar system 26, the flow water 8 flows increasingly in the direction of the return line 60, so that the entire tank 4 is soon filled to the bottom with warm flow water.
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The water flowing in through the diffuser 42 is distributed in a clearly defined horizontal plane and forms a kind of curtain that divides the upper from the lower part of the container volume 32. If more

If more warm water is supplied by the heat sources than is taken up by the heat consumers, this curtain, which acts as a temperature limit, shifts more and more downwards.

The solar system 26 always charges the (shunting) storage tank 2 when the temperature of the water provided by the solar system 26 is greater than the temperature of the lowest storage water layer.

In addition, the boiler 58 is charged if the top storage water layer has not reached the minimum temperature required for the heating system.

If more heat energy is required than is supplied by the heat sources 26, 58, the heat limit is shifted upwards. Temperature sensors of a temperature difference control system determine whether the heat limit has reached a certain predetermined level and, if necessary, give a signal to switch on the solar system 26 or, if the solar system 26 is not hot enough, to switch on the boiler 58.

Because the volume flow in the shunting tank 2 is generally significantly lower than the volume flow in the inlet and outlet lines, the flow speed in the water storage tank 4 is generally very low. This effect is another reason why turbulence in the water in the (further) tank 32 is largely avoided.

Water storage tank, especially for a central heating system with solar collector

List of reference symbols

2 (Varm) water storage tanks, shunting storage tanks

4 vessel, container

6 feet

8 Pipe socket, primary flow

10 Pipe socket, primary return

12 pipe sockets, secondary flow

14 Pipe socket, secondary return

16 Honeycomb panel

18 Scale sheet

20 scales

22 slots

24 separated area of the container

26 Solar system

28 Solar collector

30 heat exchangers (of the solar system)

32 (additional) container room

34 Pipe socket, flow solar system

36 Plate

38 Gas separators

40 vent pipe

42 Diffuser

44 opening

46 Baffle plate

48 dirt separators

50 Drain opening

52 Magnetite separators

54 radiators

56 domestic hot water heat exchangers

58 boilers

60 Return solar system

62, 64, 66, 68, 70, 72,

Pipe socket for temperature sensor

Claims (6)

Protection claims 1. (Water) storage (2), a so-called "layered" or "buffer" storage tank for storing hot water and/or for storing thermal energy in the form of heated water (or a similar heat transfer medium), with at least one flow line <8>, (12) and at least one return line (10), (14) on the primary and secondary sides,
wherein the storage tank (4) simultaneously represents a "hydraulic switch" for decoupling the heat sources that can be connected on the primary side (such as a heating boiler (58), solar system (26), district heat exchanger and/or heat pump) from the various heat consumers that can be connected on the secondary side (such as radiators (54) and heat exchangers (56) for heating drinking water), and wherein a charge change device arranged within the water tank (2) is provided for directing the hot water inflow from a solar collector heat exchanger (30), characterized in that the charge change device comprises a honeycomb plate (16) arranged vertically in the container (4), which forms behind it a narrow container area (24) separated from the further container space (32) and which is connected to the flow of the solar collector heat exchanger (30) via a pipe socket (43) arranged in its lower area, and that on the honeycomb plate (16) on the side facing the container interior (32) there is a scale plate (18) which is provided with slots (22) which are covered with downwardly directed pivotable scales (20), wherein the scales (20) have a valve effect in such a way that that they keep the slots (22) closed with equal pressure on both sides and when there is excess pressure from the side of the honeycomb plate (16), the slots (22) open towards the (further) container space (32). 2. Memory according to claim 1, characterized in that the scale plate (18) consists of a stainless steel foil. 3. Memory according to claim 1 or 2, characterized in that the primary-side (10) and secondary-side heating return (14) and the solar collector return (60) are arranged at the lower end of the container (4), and that the container (4) is equipped with a transverse, i.e. horizontally arranged plate (36) just above the pipe sockets (10), (14) and (60) of the returns, which has an opening (44) in its center, opposite which a baffle plate (46) is located above at a small distance. - 12 - 4. Storage tank according to one of claims 1 to 3, characterized in that the primary-side flow inlet (8) located in the upper part of the tank <4> is provided with a diffuser (42) for the star-shaped, horizontal and layered feeding of the warm flow water into the storage tank <4), and wherein between the flow inlet (8) and the diffuser (42) a Gas-<air- ) separator <38) is arranged. 10 5. Storage according to one of claims 1 to 4, characterized in that a dirt separator <48) is provided in the lower part of the storage container <4), which comprises a magnetite separator <52) for separating ferromagnetic particles. 6. Storage tank according to one of the preceding claims, characterized in that temperature sensors for controlling the heating circuits are arranged at different heights within the container <4).