DE29706808U1 - Buffer storage and heat collection and distribution system with a buffer storage - Google Patents

Description

PFISTER & PFISTER PATENT ATTORNEYS *" Dipl^ng. UelmufPfiiter

European Patent Attorney

Dipl.-Phys. Stefan Pfister

17/1 D-87700 Memmingen/Bavaria

Office 1: Herrenstrasse 11

Telephone 08331/2412 Fax 08331/2407 Office 2: Buxacher Straße 9

Telephone 08331/65183 Fax 08331/65185 Postgiroamt München 1343 39-805 (bank code 700100 80) Bayer. Vereinsbank Memmingen 2 303 396 (bank code 731 200 75) VAT ID No. · VAT Reg. No. · N° CEE DE 129 066 032

■16 APR 19 9 7

Company Ikarus Solar Wholesaler Rainer Berkmann, Fabrikstraße 14, 87437 Kempten

"Buffer storage and heat storage and distribution system with

a buffer storage"

The invention relates to a buffer storage according to the preamble of claim 1.

The well-known boilers can be considered buffer storage, for example. The general purpose of buffer storage is to absorb the heat energy generated by a heat generator, store it and release it again when required. Examples of heat generators include a heating burner, a heat pump, solar collectors, a heat exchanger, for example connected to a district heating system, and others.

The aforementioned buffer storage tanks are usually operated with water as the medium for transporting the heat energy. However, it is also possible to use gas, gaseous or solid media in addition to liquid media, or to mix these different media together. In the following, liquid media, especially water, is assumed to represent all media.

The following situation arises, particularly with the buffer storage tanks described at the beginning, e.g. designed as boilers. A temperature gradient forms in the buffer storage tanks, with the colder water usually at the bottom and the hotter water at the top. Due to the system, a temperature gradient δ�T/δθ is therefore present in the buffer storage tank (δθ corresponds to the height coordinate). There are now two problems. The water is fed into the buffer storage tank from the heat generator and leads to undesirable mixing there. Mixing is therefore not beneficial because, due to the thermodynamic law of entropy (second law), this leads to 6T generation, which reduces the overall efficiency or the hotter water is mixed down to a lower temperature and the hot temperature level is therefore no longer available.

The same problem arises with consumers, as they may not need to be operated with a flow temperature of 70 ⁰ C, but a low temperature level is often sufficient to operate, for example, underfloor heating or the like. If the consumer is operated at too high a temperature, cold water must be added, which leads to the aforementioned mixing losses.

It should also be noted that under certain circumstances the return flow may have a relatively high temperature, which in turn can lead to undesirable mixing effects.

The present invention has set itself the task of improving buffer storage as described above in such a way that its efficiency is improved.

This object is achieved by a buffer memory as described in claim 1.

The invention achieves that, depending on the temperature level T _x , which can be, for example, a heat energy generator or a heat energy consumer, precise and exactly matching extraction/feed temperature T _e can be set. Here, T _e is between T^ and T ₂ . Usually,

T _x = T _e .
However, it can happen that

_Tx > _T2

In such a constellation, for example, it is intended that the extracted heat energy is deposited in the buffer storage above the temperature level T _2. Possible mixing losses are accepted here, although it should be noted that this is a question of the design of the buffer storage or the entire heat collection and distribution system in order to avoid such mixing losses that may still occur. The same procedure is followed in the constellation in which

_Tx < _T1

where the medium with the lower temperature level is below the medium with the temperature level T^ in

buffer storage is stored.

The effect according to the invention is that the exact correct layer temperature or extraction/feed-in temperature T _e is offered according to the external temperature level T _x of the heat energy generator or heat energy consumer. This means that all connected consumers or generators can be operated at a suitable, constant temperature level T _e , whereby this can then be optimally adapted to the respective characteristics or efficiency curves or ambient conditions. It is precisely the adaptation to the properties of the external temperature levels, i.e. the heat energy generator or consumer, which is carried out with the help of appropriate intelligent controls (microprocessor), which results in a further improvement in the efficiency of the elements connected to the buffer storage.

A particular advantage of the invention is that the control of the extraction and/or supply opening is continuous. The continuous control makes it possible to immediately follow even small temperature differences and the water fed in or drained off is always at the correct temperature, which on the one hand avoids mixing losses and on the other hand allows the characteristics of the energy generators or consumers connected to the line to be followed precisely.

A further increase in efficiency is achieved if layered partition walls are provided in the buffer storage, so that a certain partial volume of the buffer storage is closed off from the usual buffer storage. In fact, a small buffer storage is created in the large buffer storage. It is possible, for example, to create a relatively larger volume of a certain temperature level with relatively low temperature gradients within the

Buffer storage is to be formed in order to store heat energy at a certain, preferred temperature level. The layer partition walls are insulated in such a way that heat conduction through the partition walls is prevented as effectively as possible.

The invention relates not only to a buffer storage tank alone, but also to a heat collection and distribution system with a buffer storage tank, as previously described. These heat collection and distribution systems are to be viewed as complete systems, with a potentially very complex structure. The characteristic feature of these systems is that the heat energy is always generated by one or more generators and is stored and stored in the buffer storage tank and released again to various energy consumers as required.

Since the heat energy generators, as well as the heat energy consumers, have characteristics where the efficiency is optimal. Reference should be made to the properties of solar collectors or boilers, the full success of the invention is evident here. The connected generators/consumers can work independently of one another if these energy generators can operate at a constant, precisely definable temperature level and thus exactly follow their characteristics in the area of maximum efficiency.

Further advantageous embodiments are described in the subclaims or explained using the following figures.

The invention is shown schematically in the drawing. It shows:

Fig. 1 a block diagram of a buffer

storage in a heat collection and distribution system, according to the invention,

Fig. 2, 3 in a schematic three

dimensional view of the two cylinders according to the invention, loading level cylinder (Fig. 2) and control cylinder (Fig. 3) and

Fig. 4 in a block diagram the output

design of the heat collection and distribution system according to the invention.

The buffer storage 1 is shown schematically in Fig. 1. The buffer storage 1 is usually arranged upright, with the motor 8 arranged at its upper end. With such geometric conditions, a temperature gradient δ�T/η is formed such that the higher temperature level T2 is at the top and the temperature level with the lower temperature Ti is at the bottom.

Water is usually used as a medium for storage or for transport through the pipe 9. However, other liquid, gaseous or solid media can also be used.

On the side of the buffer storage 1, several temperature sensors 10 are provided, which are connected to a control 5 (here, for example, via a bus connection). The sensors 10 transmit an exact temperature distribution of the buffer storage 1 to the control 5. The control 5 sets the removal and/or

Feed opening 2 is set in such a way that it corresponds exactly to the desired extraction or feed temperature T _e . Usually, the level of this extraction or feed temperature T _e depends on the temperature level T _x of the heat energy generator 6 or the heat energy consumer 50.

T _e = T _x

To determine the temperature level T _{x ,} a temperature sensor 60 is provided on the heat energy generator 6, which in turn is connected to the controller 5.

According to Fig. 1, a solar collector 61 is provided as the heat energy generator 6, which is connected to the circuit of the buffer tank 1 or the line 9 by a heat exchanger 7. The solar collector 61 is usually operated with antifreeze so that the collector is not damaged in the event of frost. A circulation pump 72 is provided, which is also monitored by the control system 5 and pumps the cold antifreeze into the solar collector 61, where the heated antifreeze then runs into the heat exchanger 7 in order to transfer the heat energy to the domestic water, the heat energy-transporting medium of the buffer tank 1.

A circulation pump 70 is also provided for the domestic water circuit, which is also controlled by the control system 5. The heated water 70 is pumped via the line 9 into the interior 33 of the inner cylinder 3. The exact structure of the cylinders 3, 4 placed on top of each other will be explained later. Based on the temperature level T _x or the temperature level determined by the temperature sensor 71, the control system 5 selects the position in the buffer tank at which the supplied heated water is fed into the buffer tank 1. For this purpose, the control system 5 detects the temperature

sensors 10 the temperature distribution and uses this information to control the rotary drive 8 in such a way that the extraction and/or supply opening 2 is at the desired feed temperature level T _e . At this position, the warm water is introduced into the buffer tank 1 to avoid unnecessary mixing losses.

The circuit is closed by the return 11. The return 11 to the heat exchanger 7 occurs at a relatively low temperature level. However, it is also possible to provide a similar removal and/or supply opening 2 for the return to the heat exchanger 7, as is implemented for the consumers, for example (see Fig. 4).

Two cylinders 3, 4 placed one above the other are provided in the buffer storage 1. This is a control cylinder 4, which is actuated by a rotary drive 8.

A bolt 43 protrudes from the top surface of the cylinder 4, to which the claw coupling engages, which is connected to the rotary drive 8. The two cylinders 3, 4 are arranged in the buffer storage in such a way that their longitudinal axes 30, 40 are aligned parallel to the temperature gradient, i.e. are arranged upright according to Fig. 1.

The motor 8 or the claw coupling are located, for example, outside the buffer tank 1, as indicated in Fig. 1. However, it is also possible to arrange the claw gear in the buffer tank and/or the motor 8 below the upper flange cover 12.

The control cylinder 4 overlaps the loading level cylinder 3. The loading level cylinder 3 is mounted on the lower flange cover 13, for example welded or screwed to it, with the inner area 33 connected to the line 9

—9—

Line 9 connects the buffer storage tank with the heat energy generators or consumers.

The first cylinder, which can be the loading level cylinder or control cylinder, has a longitudinal groove 42 arranged parallel to the longitudinal axis 40 on the outer surface 41. The second cylinder, which can be the control cylinder or the loading level cylinder, has a screw groove 32 in the outer surface 31. The grooves 32, 42 penetrate the cylinder jackets 31, 41 completely in a slot-like manner. The two cylinders can be rotated against each other, for example due to the rotary drive 8, whereby the overlap area of the longitudinal groove with the screw groove can be adjusted by the rotation and thus form the adjustable removal and/or feed opening 2. The main advantage of this invention is that continuous adjustment is possible.

For precise control of the removal and/or feed opening 2, the temperature values recorded by the temperature sensors 10 are interpolated. This is done in the control 5.

The loading level cylinder, i.e. the inner cylinder 3, has

for support at the upper end a tip 34, which is attached to the

outer cylinder placed over it and thus creates a guide.

The use of a claw coupling is advantageous because it allows axial play, which can arise due to thermal expansion, to be easily compensated. Conventional sealing agents, such as fabric bushings and the like, are provided for sealing the passages.

The loading level cylinder 3 has a screw groove 32 - this can also be spiral-shaped - this groove

- 10 -

«j· ·■ ·■·;

- 10 -

describes an angular range of 340° on the outer surface. This means that the longitudinal groove in conjunction with the screw groove only forms one removal and/or feed opening. However, particularly with difficult geometric designs of the buffer storage, it is advantageous not to arrange screw grooves that are too steep, in which case the entire height of the buffer storage can no longer be reached with an angular range of 340°. For this purpose, the inner area 33 of the cylinder is designed to be controllable sector by sector, in which case cascading is possible and the screw groove describes significantly more than 340°. Due to the intelligent control of the inner sectors, only the desired one of the various overlapping areas is controlled as a removal and/or feed opening 2.

As indicated in Fig. 1, the line 9 is led through the flange base 13 outside the buffer storage tank 1. However, it is also possible to integrate the inventive concept into existing buffer storage tanks 1 or to install it later, in which case the line 9, suitably insulated, is led through the buffer storage tank 1 and, for example, is also led out of the top of the buffer storage tank 1.

To improve the thermal energy storage, the buffer storage is provided with layered partition walls, which are not shown in the figure. It is also possible to aim for a mixture of solid and liquid storage media, for example, paraffin enclosed in aluminum is used as a storage medium, whereby the paraffin has different melting points depending on its mixtures and thus produces an ideal heat storage device at constant temperatures. Due to the heat of fusion, larger amounts of energy can be deposited at defined temperatures. The aluminum used in these balls is well known and

- 11 -

- iii -

ensures optimal heat conduction within the balls. The balls or other geometric bodies are surrounded by the water and transport the energy into and out of the storage unit. The dimensions or shape of the bodies are such that it is not possible to close the removal and/or supply opening 2.

A complex heat collection and distribution system is shown in Fig. 4. In addition to a large number of heat energy generators 6, for example a solar collector 61, a heating burner 62 and a heat exchanger 63, which is connected to a district heating network, for example, a heat consumer 51, namely a heater 50, is also indicated here. All of the aforementioned components are connected to the buffer storage tank 1 by corresponding lines 9. It is indicated that the supplied heat energy can be introduced at any point (= temperature level) within the storage tank through the separately controllable extraction and/or supply openings 2 and can also be removed again for the consumers at any point.

Oil, gas, condensing boilers or heat pumps etc. can be operated in the optimal efficiency range by variable adjustments of the return temperature. With regard to the solar collectors, it is advisable to use different charging modes in order to make solar operation efficient. It is also possible to implement self-sufficient solar heating systems.

The claims filed now with the application and subsequently are attempts to formulate without prejudice to obtain more extensive protection.

The references cited in the dependent claims indicate the further development of the subject matter of the main claim through the features of the respective subclaim

- 12 -

However, these are not to be understood as a waiver of the achievement of independent, objective protection for the features of the referenced subclaims.

Features that were previously only disclosed in the description can be claimed in the course of the procedure as being of essential importance to the invention, for example to distinguish it from the prior art.

Claims (1)

PFISTER & PFISTER PATENT LAWYERS · ^: · Dipi.-incTHeirtiut European Patent Attorney Dipl.-Phys. Stefan Pfister D-87700 Memmingen/Bavaria
Office: Herrenstraße 11 17/9 Telephone 0 83 31/2412 Fax 0 83 31/24 07
Office 2: Buxacher Straße 9 Telephone 0 83 31/6 5183
Fax 08331/65185
Postgiroamt Munich
1343 39-805 (bank code 700100 80)
Bayer. Vereinsbank Memmingen
2 303 396 (bank code 731 200 75)
VAT ID No. · Vat Reg. No. · N° CEE
DE 129 066 032 16 APR. 1997 Protection claims 1. Buffer storage for the storage of thermal energy, wherein a temperature gradient between a minimum temperature T^ and a maximum temperature T2 prevails in the buffer storage and the buffer storage has a removal and/or supply opening for the medium transporting the thermal energy, wherein the removal and/or supply opening (2) is connected by a line to a temperature level T _x separate from the buffer storage, characterized in that the removal and/or supply opening (2) is movable along the temperature gradient, and that depending on the temperature level T _x the removal and/or supply opening (2) can be controlled to a corresponding removal/supply temperature T _e . 2. Buffer storage according to claim 1, characterized in that the control (5) of the removal and/or feed opening (2) is continuous. 3. Buffer storage according to one or both of the preceding claims, characterized in that temperature sensors (10) are provided along the temperature gradient and these transmit the temperature distribution in the buffer storage (1) to a controller (5). 4. Buffer storage according to one or more of the preceding claims, characterized in that the control (5) is connected to a temperature sensor (60) at the temperature level T _x . 5. Buffer storage according to one or more of the preceding claims, characterized in that the temperature level T _x separate from the buffer storage (1) is formed by a heat energy generator (6) or by a heat energy consumer (51). 6. Buffer storage according to one or more of the preceding claims, characterized by two cylinders (3, 4) placed one above the other, a control cylinder (4) and a loading level cylinder (3), the longitudinal axis (30, 40) of the cylinders (3, 4) being oriented essentially along the temperature gradient, and the first cylinder (4) having a longitudinal groove (42) arranged parallel to the longitudinal axis (40) in the jacket surface (41) and the second cylinder (3) having a screw groove (32) in the jacket surface (31), the inner region (33) of the inner cylinder (3) being connected to the line (9), the cylinders (3, 4) being rotatable relative to one another and the overlap region of the longitudinal groove (42) with the screw groove (32) forming the removal and/or supply opening (2). 7. Buffer storage according to one or more of the preceding claims, characterized in that at the control cylinder (4) is provided with a rotary drive (8), which is connected to the control (5) and, depending on the extraction/feed temperature Tg, rotates the control cylinder relative to the loading level cylinder and thus positions the extraction and/or feed opening (2) at the desired temperature level in the storage tank (1). 8. Buffer storage according to one or more of the preceding claims, characterized in that the Screw groove on the lateral surface describes an angle of approx. 340°. 9. Buffer storage according to one or more of the preceding claims, characterized in that a cascading is provided, wherein the screw groove on the outer surface describes an angle of more than 340° and sectors in the inner cylinder can be controlled separately. 10. Buffer storage according to one or more of the preceding claims, characterized in that a different medium is provided for storing the thermal energy than for transporting the thermal energy, with paraffin being provided as an additional storage medium and water being provided as a transport or storage medium. 11. Buffer storage according to one or more of the preceding claims, characterized in that the buffer storage (1) is closed at the top and bottom by flanges (12, 13) and these flanges (12, 13) form a bearing for the cylinders (3, 4), the rotary drive (8) being provided on one flange (12) and the line (9) being connected to the other flange (13). 12. Buffer storage according to one or more of the preceding claims, characterized in that the buffer storage has layer partitions. 13. Buffer storage according to one or more of the preceding claims, characterized in that the line is guided through the buffer storage. 14. Buffer storage according to one or more of the preceding claims, characterized in that several removal and/or supply openings (2) are provided in the buffer storage (1). 15. Buffer storage according to one or more of the preceding claims, characterized in that a temperature sensor (71) is provided on the line (9). 16. Heat collection and distribution system with a buffer storage tank according to one or more of the preceding claims. 17. Heat collection and distribution system according to claim 16, characterized in that one or more of the following elements is/are provided as heat generator and is/are connected to a line with a removal and/or supply opening: Heating burners, heat pumps, solar collectors, heat exchangers, district heating. 18. Heat collection and distribution system according to one of claims 16 or 17, characterized in that one or more of the following elements is/are provided as heat energy consumer and is/are connected to a line with a removal and supply opening: Process heat, heating, hot water. The