EP2795133B1 - Arrangement with storage element and heat supply system - Google Patents

Description

The invention relates to an arrangement with a storage element and a heat supply system.

It is known that heat generators, such as boilers, have to be dimensioned higher in their heat output than the predicted total demand for heat in the corresponding heat supply system. This is because the heat generators in such heat supply systems always have to be designed according to the maximum necessary heat demand.

If a heat supply system dimensioned according to this design rule is operated with a solid fuel boiler, this results in difficulties in heat balancing within such a plant.

After a proposal in CH 342 354 should therefore be assigned to such a heat supply system, a heat storage, which is connected in parallel to the existing heat consumers (radiators). The integration into the heat supply system via a three-way valve in the flow and the return line of the heat supply system and a forced circulation with a thermostat controlled circulating pump in the load circuit of the heat supply system.

Depending on the position of the three-way valves, either the consumer circuit, the heat storage or both can be put into operation.

When operating the consumer circuit together with the heat storage results in an operating regime that takes the necessary quantities of liquid practically random either the solid fuel boiler or the heat storage or both. A hydraulic compensation is not provided. Thus, the proposed system can only be operated so useful that the hot water tank is charged directly from the solid fuel boiler at the appropriate valve position, wherein in such a switching variant of the load circuit and the circulation pump are turned off. The resulting pumpless circulation extends the charging intervals.

The most significant disadvantage of this heat supply system is therefore that a hydraulic compensation and a Beauflagung the heat accumulator with a pressure flow are not possible.

In particular, an oversupply of heat quantities can also be achieved by virtue of the fact that such heat supply system has additional heat sources, such as thermal solar collectors, switched on. In particular, it comes to gross mismatches between supply of heat and their decrease. In addition, the time course between heat generation and heat consumption is not congruent.

In JP S58 28 933 A It is proposed to connect a heat generator associated memory device with 2 lines with this. In the line, which is connected to the output of the heat generator, a pump is arranged. Consequently, this pump is always in a media area with elevated temperature, which can adversely affect their life. The pump is followed by a valve unit, with the aid of which the connections of the storage device can be connected to the heated medium if required. The storage device can be mutually charged with heated medium. The respective other line is connected via the same valve unit with the return line of the heat generator, so that the heated medium from the storage device is always supplied to the heat generator.

An exclusive supply of heat consumers from the storage device is not possible.

In order to remedy this, storage elements are present in heat supply systems that offer the possibility of a temporary oversupply of heat offer to buffer these amounts of heat and retrieve them later. In order to make this possible, heated medium must be pumped in the event of an oversupply in the direction of the storage element. In case of a lack of need the same medium must be pumped in the opposite direction from the storage element back into the heating circuit.

Because of the reduced at high media temperatures lifespan of circulation pumps for some time they are only inserted in the wiring harness, which always has the lower temperature. This requires that two different directions of flow are necessary for loading or unloading the heat storage.

These objects are not to be met with a circulating pump, which is usually a centrifugal pump and can only work in one conveying direction. It is therefore already been running heat supply systems in which two pumps are connected in parallel with each other in the line circuit between the heat source and heat storage with opposite flow direction. However, these must be assigned shut-off valves, the medium should always be promoted only in a particular direction.

It is also known to arrange such an electrically controlled two-way servo valve in each parallel-connected pump assemblies in each pump branch, so as to avoid a short circuit of the media flow via the pump in each case at a standstill.

Such arrangements are expensive, especially since they require further control devices, on the one hand open and close the line paths and on the other hand, drive the two pumps.

Out DE 44 09 883 C2 an arrangement with two pumps connected in series is proposed, both of which are connected with their suction sides to the return line of a heat consumer. In this arrangement, a medium flow in the return line of a heat consumer with a pump with a heat generator (Boiler) or connected to the other pump with a heat storage. In order to avoid feedback, a check valve are proposed in the return line of the heat consumer and in the flow line of the heat generator.

This system is disadvantageous in that in the case of the assignment of further heat sources as well as in the arrangement of multiple circuits to heat consumers each have the same arrangement of pumps and check valves must be provided again. Thus, the complexity of complex systems increases very much.

In JP S58 28933 A It is proposed that the circulating pump connected downstream of a heat source in the supply line by a downstream 4/2-Wegevenil operate so that a certain number of radiators once from the first radiator starting with heated medium and once after switching the 4/2-way valve from the last radiator ago is supplied with heated medium. This arrangement has the goal to be able to exchange the supply and return line of a heat supply system with each other and to ensure in this way a uniform heating of all radiators. An extended proposal makes it possible to automatically carry out the corresponding switching at specified time intervals. Another proposal provides, upon reaching an upper limit temperature in the radiators by a heat sensor to provide a control signal to the control unit, which then interrupts the supply of the radiator.

The arrangement described above is used only for switching the supply and return line in a conventional heating circuit in order to achieve a uniform heating of all circulating radiator. For a reversal of the flow direction in a feed line of an additional heat storage, the described arrangement is not suitable.

Out EP 1 906 101 A1 An arrangement is known which connects two pumps in each case with their pressure side in a line, so by turning on each one of these pumps a certain flow direction is forced. The respectively out of service pump is flowed through by the media flow.

A comparable arrangement is known from a heat supply system Eco Zenith I 555 CTC AB, 34126 Ljungby, Sweden. In this system, additional check valves are arranged between the two pumps connected to the pressure sides.

Despite the simplified structure, this arrangement has the disadvantage that each out of service pump represents a significant line resistance, which forces to increase the pump power. Furthermore, it can not be ruled out that a correspondingly large flow of media when flowing around the rotor of the stopped pump causes corrosion and cavitation damage. These disadvantages are compounded when, in addition to the pump, non-return valves still have to be flowed through.

In addition to the disadvantages indicated in the individual solutions available in the prior art, further disadvantages are present. For example, systems that use two independent pumps require separate control, which increases the amount of control required in such heat supply systems.

If combinations with two circulating pumps are additionally equipped with actuated valves, the control effort increases even further.

In addition, in the individual components of existing in the prior art systems lack synchronization. Controlled valves or pumps generate blows in the circuits. With several solutions the hydraulic compensation is missing.

In plants which place a special emphasis on the production of renewable energies by means of solar thermal heat sources, the systems known from the prior art can not meet the requirements for a maximum Energy gain from these sources correspond. For this purpose, it is necessary to integrate in the balancing of the amounts of heat within a heat supply system, a secondary heat storage such that it can supply as needed and without inertia amounts of heat in the consumer circuit or remove from the generator circuit. The also known in the art and integrated as a heat sink in heating circuits combi memory with a large heat quantity buffer can not meet the requirements. They are too lazy in their behavior. On the other hand, a lower inertia heat sink requires a rapid response by a secondary hot water tank to approximately compensate for supply or lack of heat compared to the heating circuit of a heat supply system. This can not be achieved with the pump arrangements known from the prior art.

It is therefore an object of the invention to propose an arrangement that can take over the tasks of loading and unloading at least one heat storage in heat supply systems with low cost, installation and control, which works energy and cost optimized, pressure surges avoids, allows hydraulic compensation and be adapted in many ways with regard to their integration into existing plants.

This object above is achieved with an arrangement having the features of the characterizing part of claim 1 in conjunction with the features of the preamble of this claim. Secondary and subordinate claims describe embodiments of the arrangement according to the invention.

• Wärmeversorgungsaniage - ist eine Anordnung, die wenigstens aus einem Wärmeerzeuger, einem Wärmeverbraucher und einem über eine Pumpe ladbaren bzw. entladbaren Wärmespeicher verfügt.
• Pumpenanordnung - ist eine Zusammenstellung von wenigstens einer Pumpe beliebiger Bauart, Leitungsabschnitten und Ventilen zur Lösung der Aufgabe, mit einer Pumpeneinheit das Speicherelement zu laden bzw. zu entladen.
• Speicherelement - ist ein Volumenspeicher beliebiger Größe und Bauart, der mit einem Wärmemengen transportierenden Medium aufgeladen und wieder entladen werden kann.
• Rückflussverhinderer - ist ein Bauteil oder eine Baueinheit, die geeignet sind, den Medienstrom der Pumpe weitgehend unbehindert passieren zu lassen, bei dauerhaftem oder impulshaftem Gegenstrom in der Pumpenleitung den Leitungsstrang jedoch zu verschließen.
• Steuerbar - bedeutet, dass aufgrund willkürlicher Entscheidungen und Eingriffe in das Wärmeversorgungssystem die Inbetriebnahme der Pumpenanordnung sowie deren Stillsetzen bewirkt werden kann.
• Regelbar - bedeutet, dass das Inbetriebnehmen bzw. Stillsetzen der Pumpe von in der Anlage erfassten Messwerten, erarbeiteten Regelgrößen oder aufgrund von Behandlungsroutinen einer übergeordneten Regelanlage abhängig ist. Solcher Art Regelanlagen können in die Pumpenanordnung integriert oder als zentrale Regelanlage des Wärmeversorgungssystems ausgeführt sein.

In the following description, embodiments and claims, the following terms are used with the following meaning:

• Wärmeversorgungsaniage - is an arrangement that has at least a heat generator, a heat consumer and a pump loadable or dischargeable heat storage.
• Pump assembly - is a collection of at least one pump of any type, line sections and valves to solve the task of loading or unloading the storage element with a pump unit.
• Storage element - is a volume storage of any size and design, which can be charged and discharged with a medium carrying heat quantities.
• Backflow preventer - is a component or a structural unit, which are suitable to allow the medium flow of the pump to pass largely unhindered, however, to close the wiring harness in the event of a permanent or impulsive countercurrent in the pump line.
• Controllable - means that due to arbitrary decisions and interventions in the heat supply system commissioning of the pump assembly and its shutdown can be effected.
• Controllable - means that commissioning or shutdown of the pump depends on measured values acquired in the system, calculated control variables or due to the handling routines of a higher-level control system. Such type of control systems can be integrated into the pump arrangement or designed as a central control system of the heat supply system.

According to the invention, it is assumed that a further optimization of the use of thermal energy in heat supply systems is possible in that a memory element additionally arranged in such a system is charged or discharged with little inertia with only one pump. The previously used arrangements with two pumps are thus unnecessary.

In particular, the invention takes account of such heat supply systems, which are equipped with heat generators, are obtained by the amounts of heat from renewable energies and in which a so-called heat sink assumes the task of providing amounts of heat for the heating circuit. Nevertheless, the arrangement according to the invention is also applicable in conventional heat supply systems, provided that a secondary heat storage is additionally arranged in these.

Additional resistances through a second pump, which must be flowed through, as well as the installation and maintenance costs for a second pump. In addition, possible damage to the respective shutdown pumps due to cavitation, corrosion and aging is avoided.

According to the invention, the arrangement should be designed in such a way that by means of valves or taps a mutual connection to the supply and discharge line parts is made possible and so the conveying direction of the pump can be changed within short intervals. According to the invention, this has the advantage that only adjusting pulses with little expenditure of energy are necessary for the placement of the valves or taps, while the pump can convey media even after switching in each case in optimized operation.

In order to be able to operate the pump in an energy-optimized manner, it is controlled with optimized performance. That is, the pump is always provided the amount of energy that is necessary to comply with the required parameters.

Particularly preferred is a control of the amounts of energy of the circulation pump by controlling the pump drive motor via a pulse width control, which is controlled by analog signals and determined on the basis of the amount of energy for the operation of the circulation pump.

Particularly advantageous is the recovery of the analog signals by the arrangement of a temperature sensor at a point in the consumer circuit of the heat supply system, which is preferred for determining a target temperature in question. In this way, the charging or discharging of a connected heat storage can be controlled almost without inertia and thus compliance with thermal requirements can be ensured in a simple manner.

Such activation of the circulation pump may be carried out in parallel with or integrated into a control for the heat supply system.

In this case, it is preferable to control the amount of energy via a so-called pulse width control, since this can be carried out with inexpensive components or control or regulating units.

Particularly preferred is a pulse width control by means of a so-called switching regulator or a so-called controllable pulse modulation unit in the form of an electronic module.

In this case, the use of an electronic component of the SG3524 family is again particularly preferred because it can be regulated via an analog control signal. This provides the prerequisite for directly connecting an analog temperature sensor to the control unit of the circulating pump.

Of course, such a control can also be controlled via an analog output of a central control of the heat supply system.

In cases where occur within the heat supply systems longer conduction paths to the storage element or by the storage element increased feed pressures are required, a multi-stage pump or a pump cascade can be used, the drive can be carried out as described above.

The necessary within the pump assembly switching unit is executed in the preferred case with a 4/2 valve. This connects in a switching position, the suction side of the pump with the heat generator and the pressure side of the Pump with the storage element. In the second switching position, the suction side of the pump is connected to the storage element and the pressure side to the line to the heat generator.

Particularly preferred is for the 4/2 valve, a so-called ball valve, which has at least the two required switching positions and can be controlled with auxiliary power.

Instead of a 4/2 valve, two 3/2 valves, four 2/2 valves or ball valve arrangements can be used.

To protect the heat supply system and the pump this is a backflow preventer upstream or downstream. In this case, preference is given to the arrangement according to the pressure-side connection of the pump.

The pump assembly may be configured in a split design depending on the design of the heat supply system in a split design with intermediate line sections or as a pump assembly in a compact design or as a pump assembly.

Fig. 1 -

eine schematische Darstellung eines Wärmeversorgungssystems mit einem an diesem angeordneten Speicherelement.

Fig. 2 -

eine schematische Darstellung der erfindungsgemäßen Pumpenanordnung unter Verwendung eines 4/2-Ventils in einer Schaltstellung, bei der eine Pumpe Medienstrom in Richtung einer Wärmequelle fördert.

Fig. 3 -

die in Fig. 2 gezeigte schematische Darstellung mit einer Schaltstellung des Wegeventils, bei der die Pumpe einen Medienstrom in Richtung zu einem angeschlossenen Speicherelement fördert.

The invention will be explained in more detail below with reference to some embodiments and drawings. Showing:

Fig. 1 -

a schematic representation of a heat supply system with a memory element arranged on this.

Fig. 2 -

a schematic representation of the pump assembly according to the invention using a 4/2-valve in a switching position, in which a pump promotes media flow in the direction of a heat source.

Fig. 3 -

in the Fig. 2 shown schematic representation with a switching position of the directional control valve, in which the pump promotes a flow of media in the direction of a connected storage element.

A heat supply system of the type known per se consists of a heat generator 1, a heat consumer 2 and the lines connecting them 3 for the warm area (flow) and 4 for the cold area (return).

In addition, a heating circulation pump 5 can be integrated in the heat supply system.

From the line 4 line sections 6 and 7 are guided to a storage element 8 . Between the line sections 6 and 7 , a pump assembly 9 is also arranged, which loads the storage element 8 depending on the need or discharges.

Via a connecting line 10 , the storage element 8 may be connected to the line 3 , so that heated medium from the storage element 8 can be fed directly into the supply circuit.

The pump assembly according to the invention in the line sections 6 and 7 consists of a pump 11, a 4/2-way valve 12, a backflow preventer 13 and the connecting lines 14,15 and 16.

In Fig. 2 is the 4/2-way valve 12 in a first switching position, which can also be referred to as 0 ° position. The switching element 17 then directs the medium from the line section 7 via the line 14 to the pump 11, further via the line 15, the backflow preventer 13 and the line 16 in the line 6. In this way, a heat consumer 2 by discharging a in Fig. 2 Memory element, not shown, are supplied with heated medium.

In the in Fig. 3 shown switching position corresponding to the 90 ° position, the 4/2-valve 12 is connected so that loading a in Fig. 3 not shown storage element is possible. From a heat generator 1 is heated via line 6, the 4/2-valve 12, the pump 11, the line 15, the backflow preventer 13 and the line 16 heated medium in the conduit 7 . The discharged from the storage element medium is pumped via line 10 in the direction of a heat consumer 2 .

The backflow preventer 13 is arranged on the pressure side of the pump 11 and connected thereto via the line 15 . In this way, backflows are prevented in the line circuit, it does not matter whether the return flow would occur like a pulse or due to a back pressure created permanently.

For the invention, it does not matter in which way and with which connection types the pump arrangement is connected to the heat supply system. This applies in particular to the feed points to which the line sections 6 and the line 10 are connected. Nor is it important for the invention whether the conduit 10 is present in the system.

The pump 11 is preferably a power-controlled pump. Particularly preferred here is a pump control, which works with a pulse width control and the pump 11 can always provide the amount of energy that are required for the fulfillment of the task just.

The control of the pump 11 can be realized via a separate control module or by a central control of the heat supply system. It is also possible to influence the flow of energy to the pump 11 by controlling interventions.

The pump 11 is supplied with an analog signal, so that a control module or a central controller can generate a pulse-modulated oscillation therefrom.

The pulse modulated oscillation is generated by an integrated switching regulator or a controlled pulse width modulator, wherein the modulator preferably recourse to circuits of group SG3524 or their derived model.

The control of the module is preferably carried out with analog signals in a voltage range between 0 and 10 V. The switching regulator or modulator preferably operates at a frequency of 4 kHz.

The 4/2-way valve 12 is replaced by other equivalent valve arrangements at the expense of certain disadvantages. For example, by an arrangement with two 3/2 valves, by an arrangement with four 2/2 valves or with an arrangement of several ball valves. It is ultimately important that a swap of the suction and the pressure side of the pump 11 with respect to the line sections 6 and 7 is effected.

However, particularly preferred is a 4/2 valve 12 in the embodiment as a ball valve because of the simple structure thereof and the reliable operation.

Also, the 4/2-valve 12 and the other circuits are each adjustable via control commands and power supply and require no manual operation.

The non-return valve 13 can be designed in various ways. So it may for example be a device that works with a float or a device that is provided with a pivoting non-return valve. Another embodiment is that the closure body is spring loaded and the backflow preventer 13 is accordingly designed as a check valve.

The inventively designed pump assembly is able to allow both in cooperation with a boiler as well as in cooperation with a heat sink effective control of the heating circuit.

In particular, the known fluctuations in the energy supply of solar collectors integrated in heat supply systems can be compensated for by means of the pump assembly according to the invention and their control by the pump is switched in a conveying direction depending on the heat supply or heat removal, that it takes the heated circuit excess heated medium or the heating circuit the buffer storage excess heated medium supplies.

The simultaneous pulse width modulated power supply of the pump ensures that it always works with the optimized volume flow and avoids an overshoot of the temperatures in the heating circuit.

It is possible to arrange a temperature sensor, which supplies an analogue measurement signal, at a location of the heating circuit which has been found to be optimal in order to realize in this way an operation of the heating circuit under optimum conditions.

The pump arrangement described above thus has the advantage that it allows a simple operation of the pump in two flow directions and thereby the cost of components and the fluid mechanical design can be optimized. Furthermore, the energy input is minimized by the solution according to the invention such that the flow losses are kept low, valve controls are powered only when necessary and the pump contained in the arrangement receives only the amounts of energy that are just necessary for the performance of the task.

LIST OF REFERENCE NUMBERS

1

heat generator

2

heat consumer

3

management

4

management

5

heat circulating pump

6

line section

7

line section

8th

storage element

9

pump assembly

10

connecting line

11

pump

12

4/2-valve

13

Backflow preventer

14

management

15

management

16

management

17

switching element

Claims (10)

1. An arrangement with a storage element (8) and a heat supply system, wherein a heat generator (1) is connected to a heat consumer (2) in a first line circuit and a circulation of a heating medium can be achieved between the latter with a heating circulation pump (5)
   and, with a second line circuit, a storage element (8) and a pump arrangement (9) can be connected to the first line circuit, that a media flow from the storage element to the heat consumer can be achieved as required with the aid of the pump arrangement and the storage element (8) disposed in the second line circuit can thus be discharged,
   characterised in that,
   with the aid of the pump arrangement (9), a media flow can be achieved as required from the heat generator (1) to the storage element (8) and the storage element disposed in the second line circuit can thus be charged,
   the pump arrangement (9) is an arrangement comprising a pump (11), a switch-over unit and a backflow preventer (13) and the latter interact with one another in such a way that,

   - in a first position of the switch-over unit, the pump (11) is connected - at the suction side - to the storage element (8) and at the pressure side to the first line circuit, wherein medium with a low temperature is fed to the latter from the storage element (8),

   - in a second position of the switch-over unit, the pump (11) is connected - at the pressure side - to the storage element (8) and at the suction side to the first line circuit, wherein medium with a low temperature is extracted from the latter and delivered by the pump (11) into the storage element (8).
2. The arrangement for operating a storage element (8) in a heat supply system according to claim 1,
   characterised in that
   the pump (11) is controlled or regulated in terms of its output by means pulse width modulation (PWM) as a function of the magnitude of analog input signals.
3. The arrangement for operating a storage element (8) in a heat supply system according to claim 2,
   characterised in that
   the control or regulation of the pump (11) takes place by supplying the latter with at least one analog signal.
4. The arrangement for operating a storage element (8) in a heat supply system according to any one of claims 1 to 3,
   characterised in that
   the pump (11) is constituted multi-stage or as a pump cascade with at least one further pump.
5. The arrangement for operating a storage element in a heat supply system according to any one of claims 1 to 4,
   characterised in that
   the switch-over unit is an arrangement which, without changing the rotational direction or delivery direction of the pump (11), enables switching-over of line connections in the second line circuit and at least two delivery directions of the media flow for charging and discharging the storage element.
6. The arrangement for operating a storage element (8) in a heat supply system according to claim 5,
   characterised in that
   the switch-over unit is constituted with a 4/2-valve (12) or a 4/2-stopcock.
7. The arrangement for operating a storage element (8) in a heat supply system according to claim 6,
   characterised in that
   the switch-over unit is constituted with two 3/2-valves, two 3/2-stopcocks or with four 2/2-valves or four 2/2-stopcocks.
8. The arrangement for operating a storage element (8) in a heat supply system according to any one of claims 6 or 7,
   characterised in that
   the valves or stopcocks can be actuated with auxiliary energy.
9. The arrangement for operating a storage element (8) in a heat supply system according to any one of claims 1 to 8,
   characterised in that
   the backflow preventer (13) is located upstream or downstream of the pump (11) or of the pump cascade.
10. The arrangement for operating a storage element (8) in a heat supply system according to claim 9,
    characterised in that
    the backflow preventer (13) is constituted with a flow-controlled float and/or a flow-controlled flap and/or with a flow-controlled and spring-loaded element.

Images