EP0957319A2 - Method for operating a closed loop heating or cooling system and a closed loop heating or cooling system - Google Patents

Abstract

If a circulating water heating system is to supply two heating circuits with a different temperature, the boiler is usually moved smoothly according to the needs of the higher-temperature circuit (direct heating circuit), while the lower-temperature circuit is coupled to the direct heating circuit by a mixing valve (mixer circuit). The solution still has the disadvantage that the overall efficiency of the thermal process is unsatisfactory. The same applies to appropriately designed cooling systems. The method provides that the mixer circuit is fed in a controllable manner by the flow and / or the return of the direct heating circuit. In the case of low load, the mixer circuit is preferably fed exclusively by the return of the direct heating circuit and regulated exclusively by admixing its return and, in the case of heavy load, is fed by the flow and return of the direct heating circuit and regulated exclusively by mixing the flow and return of the direct heating circuit. The process is suitable for all circulating liquid heating or cooling systems with several heating and cooling circuits at different temperatures and can be used for any heating or cooling fluid. <IMAGE>

Description

The invention relates to a method for operating a circulating liquid heating or cooling with a supply and a return line on the heat / cold generator directly connected direct heating circuit and one with the flow and the Return line of the direct heating circuit connected in parallel, by admixing its return regulated mixer circuit and a circulation liquid heating suitable for its implementation or cooling.

A circulation water heating system with one heat generator is two different supply temperature-controlled heating circuits, the boiler will usually slide to meet the needs of the higher circuit to be tempered (direct heating circuit), while the lower one to be tempered Circuit is coupled to the direct heating circuit by a mixing valve (mixer circuit). Spread is the combination of radiators and underfloor heating in buildings with one Heat generators are equipped. Usually the radiators then slide controlled direct heating circuit and the underfloor heating on the mixer circuit. Of the Mixer circuit is fed from the flow water of the direct heating circuit.

Such a circulation water heating system is known from DE 35 39 327 A1 Method for controlling a circulation water heater of a central heating system disclosed in which is the higher of the two flow temperature setpoints of the direct heating circuit and the mixer circuit serves as a reference variable for the circulating water heater.

The solution still has the disadvantage that the overall efficiency of the thermal process is unsatisfactory. It is known that the lower the efficiency, the higher the efficiency Return temperature can be maintained at a given flow temperature. Analogous applies to refrigeration generators that the return temperature for a given flow temperature if possible should be high.

The object of the invention is therefore to provide a method of the type mentioned at the beginning and one its implementation to indicate suitable circulating liquid heating or cooling with which the temperature of the return in the direct heating circuit for a given boiler flow temperature and given circulating currents is lowered as far as possible or kept as high as possible.

a) Der Mischerkreis wird vom Vorlauf des Wärme-/Kälteerzeugers gespeist,

b) der Mischerkreis wird regelbar vom Vorlauf des Wärme-/Kälteerzeugers und vom Rücklauf des Direktheizkreises gespeist,

c) der Mischerkreis wird vom Rücklauf des Direktheizkreises gespeist.

According to the invention, the object is achieved in that the following three operating states are possible:

a) The mixer circuit is fed by the flow of the heat / cold generator,

b) the mixer circuit is controlled by the flow of the heat / cold generator and the return of the direct heating circuit,

c) the mixer circuit is fed by the return of the direct heating circuit.

The process is preferably carried out so that the mixer circuit at low load fed exclusively by the return of the direct heating circuit and exclusively by Mixing of its return flow regulated and with heavy load from the flow of the heat / cold generator and the return of the direct heating circuit and fed exclusively by Mixing of these heat / cold flows is regulated, with idling as an extreme case of Low load operation and full load are to be seen as an extreme case of heavy load operation which the admixing of direct heating circuit return is regulated to zero.

The conventional method for coupling a mixer circuit to a direct heating circuit is improved with the method according to the invention that, as a rule, a lowering the return temperature of the direct heating circuit (in refrigeration systems, an increase in Return temperature), which leads to an increase in efficiency - especially at Condensing boilers - leads. This is achieved in that at a sufficient temperature in the Mixer circuit First, return water from the direct heating circuit is fed into the mixer circuit flow water is only used when the temperature is higher or analogous to refrigeration systems with lower temperature requirements. There can be one for each suitable fluid can be used.

A circulating liquid heating or cooling suitable for carrying out the method is According to the invention constructed so that the mixer circuit on the input side via a second controllable Three-way mixing valve with the flow and return lines of the direct heating circuit connected is.

The three-way mixing valves are expedient because they are equipped with limit switches Actuators can be operated.

The servomotors are advantageously mutually locked by limit switches so that only after Opening the first three-way mixing valve driven by a first servomotor Open the second three-way mixing valve driven by a second servomotor and Only after the second three-way mixing valve has been closed does the first three-way mixing valve close is possible.

The first three-way mixing valve in the from the return of the Mixer circuit branching line a check valve and / or the second three-way mixing valve in the line branching from the inlet of the direct heating circuit and / or a check valve in the line branching off from the return of the direct heating circuit upstream and / or in the return of the direct heating circuit between the connection of the A throttle valve can be arranged in the supply and return lines of the mixer circuit.

The two three-way mixing valves can be functionally combined to form a four-way mixing valve with three inputs and one output as well as an actuator, whereby only the first and the second or the second and the third entrance open at the same time could be.

A particularly advantageous, industrially prefabricated solution results when the four-way mixing valve Pipe connections for the flow and return of the direct heating circuit, pipe connections for the forward and return flow of the mixer circuit and the connections of the boiler and Mixer circuit to a unit with a flow inlet, a flow outlet, one Return input and a return output of the direct heating circuit and a flow output and a return inlet of the mixer circuit. In the unit can also at least one upstream of the inputs of the four-way mixing valve and / or the Flow of the direct heating circuit assigned check valve and / or the return of the Direct heating circuit associated throttle valve can be integrated into the unit, so that the Unit directly between the boiler and the pumps for the two water or Coolant circuits can be set.

Fig. 1

eine Prinzipdarstellung des erfindungsgemäß an einen Direktheizkreis gekoppelten Mischerkreises einer Umlaufwasserheizung,

Fig. 2

eine Prinzipdarstellung der bisher bekannten Ankopplung,

Fig. 3

ein Beispiel für eine mögliche Schaltung der Stellmotoren der Mischventile des Mischerkreises,

Fig. 4

ein erfindungsgemäßes Vier-Wege-Mischventil in einer symbolhaften Darstellung und

Fig. 5

eine Prinzipdarstellung einer zweiten Variante der Erfindung mit einem Vier-Wege-Mischventil.

Fig. 6

eine Prinzipdarstellung einer Variante ähnlich der von Fig. 5, jedoch mit einem wandhängenden Wärmeerzeuger.

The invention will be explained in more detail below on the basis of exemplary embodiments. Show in the accompanying drawings

Fig. 1

1 shows a schematic diagram of the mixer circuit of a circulating water heater coupled to a direct heating circuit,

Fig. 2

a schematic diagram of the coupling known to date,

Fig. 3

an example of a possible switching of the actuators of the mixing valves of the mixer circuit,

Fig. 4

an inventive four-way mixing valve in a symbolic representation and

Fig. 5

a schematic diagram of a second variant of the invention with a four-way mixing valve.

Fig. 6

a schematic diagram of a variant similar to that of Fig. 5, but with a wall-mounted heat generator.

Fig. 1 shows the invention in a schematic diagram. A pump P1 supplies the n radiators HK, which directly with the boiler flow Q1 of a heat generator WE (boiler) and the Boiler return Q4 are connected (direct heating circuit). The check valve ÜV1 is as Gravity brake designed for the circuit current Q2. At the node K1 there is a feed current Q3 of the boiler flow water for feeding into the mixer circuit of an underfloor heating system branched, which is equipped with a pump P2, the circuit current Q8 in the mixer circuit drives. In the three-way mixing valve MV1, this is done according to the mode described below Mix the feed water of the mixer circuit with the return flow Q7 of the underfloor heating so that any intermediate temperature is generated in the flow water of the mixer circuit can.

The temperature of the return flow in the heat generator WE at a given boiler flow temperature and lower given circulating currents Q2 and Q8 as much as possible, becomes firmer Boiler output, the amount of water in the boiler flow Q1 is kept as small as possible. Since the Circular current Q2 is considered as given, the feed current Q3 or the return current Q6 to reduce the mixer circuit. This is done by combining two three-way mixing valves MV1 and MV2, the mixing valve MV2 and thus the feed of the Mixer circuit with the flow of the direct heating circuit (feed current Q3) and with the return of the direct heating circuit (supply current Q5) is connected.

The mixing valves MV1 and MV2 are to be cascaded in the following manner:

If the mixing valve MV1 is not completely open, then the mixing valve MV2 is completely closed or return flow Q7 ≠ 0 ⇒ supply current Q3 = 0, supply current Q5> = 0 and
if the mixing valve MV2 is not completely closed, then the mixing valve MV1 is fully open or feed current Q3 ≠ 0 ⇒ return flow Q7 = 0, feed current Q5> = 0.

The case
Mixing valve MV1 not fully open and mixing valve MV2 completely closed or return flow Q7 ≠ 0 and feed current Q3 = 0 represents the light load case
and the case
Mixing valve MV2 not fully closed and mixing valve MV1 fully open or feed current Q3 ≠; 0 and return flow Q7 = 0 represents the heavy load case.

The case
Mixing valve MV1 fully open and mixing valve MV2 fully closed or return flow Q7 = 0 and feed current Q3 = 0 is the permissible limit load case.

The case is excluded
Mixing valve MV1 not fully open and mixing valve MV2 not fully closed or return flow Q7 ≠ 0 and feed current Q3 ≠ 0, since the mixing valve MV1 is always fully opened before the mixing valve MV2 begins to open. The reverse process takes place when the mixing valve MV2 and then the mixing valve MV1 are closed.

Full load is to be understood as the state in which both mixing valves MV1, MV2 are complete open or return flow Q7 = 0 and feed current Q5 = 0 or feed current Q3 = Return flow Q6 - and when idling, the one in which both are completely closed or Feed current Q3 = 0 and feed current Q5 = 0.

In the case of a low load, the mixer circuit is therefore controlled solely by adding the return flow Q7 regulated with the help of the mixing valve MV1. The load requirement increases above the If the limit load is exceeded, the mixer valve MV1 remains open and the return flow becomes Q7 Zero. The mixer valve MV2 also opens and now partially extracts water the flow of the direct heating circuit until the case occurs at full load that the water for the Flow of the mixer circuit is taken solely from the flow of the direct heating circuit.

The state of the art of coupling a mixer circuit to a direct heating circuit by means of a three- or four-way mixing valve MV1, on the other hand, represents FIG. 2.

auf-stop-zu" auf einen Stellmotor M. Die Verwendungsmöglichkeit anderer Stellantriebe ist jedoch ebenfalls gegeben. The pump P1 in turn supplies the n radiators HK, which are connected directly to the heat generator WE (boiler). With this arrangement, the return flow Q6 from the mixer circuit is equal to the feed current Q3 into the mixer circuit. The control manipulated variable acts, for example, by means of a three-point signal

auf-stop-zu "on a servomotor M. However, other actuators can also be used.

Correspondingly, regulation by means of two servomotors M1 and M2 for the mixer valves MV1 and MV2 of the arrangement according to the invention described in FIG. 1 is possible. The wiring of the limit switches of the two servomotors M1 and M2 shown in FIG. 3, for example, enables the above-mentioned catalog of requirements to be achieved and, at the same time, an actuator for the three-point signal described above that is continuous to the outside OPEN-STOP-CLOSE ".

The position of the limit switches shown in FIG. 3 corresponds to the rest position, that is to say initially an overall circuit in an illegal state, since none of the servomotors M1 and M2 is in an end position. A first change in the rule game already leads to that one of the permitted cases occurs, ie the mixing valve MV1 opens completely and then the downstream mixing valve MV2 opens or the mixing valve MV2 completely closes and then the downstream mixing valve MV1 closes.

Compared to the conventional coupling in Fig. 2, the boiler flow Q1 is unchanged Circular currents Q2 and Q8 in Fig. 1 lower by the amount of the feed current Q5, which is fixed Flow temperatures and fixed boiler output for the desired effect of lowering the temperature leads in the boiler return. At the same time, the three-point steep signal can be present Control can be used because the arrangement is equivalent to the controlled variable - Flow temperature in the mixer circuit - has the same effect as in conventional coupling.

A device is described below with reference to the symbolic representation in FIG. 4 become, which realizes the method in an economically advantageous manner. It consists in essentially from the combination of the two three-way mixing valves into a four-way mixing valve MV with a movable valve body, a drive element M at same steep behavior as described above, three inputs 1, 2 and 3 and one output 4. It is irrelevant whether the moving body is a lifting or Rotational body.

Rather, the function of the mixing valve is clear due to the following properties marked:

The area of stay of an actuator not shown here is in with constant mobility three points (end point I, center point, end point II) and two areas (area I, area II) divided, which is analogous to the above definition as full load, heavy load, limit load, Low load and idle can be called. At full load there is only one connection from input 1 to output 4, with heavy load can slide by moving the actuator any mixing ratio of inputs 1 and 2 to output 4 can be achieved at Limit load is only a connection from input 2 to output 4, with low load can by moving the actuator slidably any mixing ratio of the inputs 2 and 3 can be reached to output 4 and there is only a connection from input 3 when idling to exit 4.

The following Tab. 1 is intended to clearly illustrate the relationships described. Load case Full load Heavy load Limit load Light load Neutral Entrance 1 open partially open closed closed closed Entrance 2 closed partially open open partially open closed Entrance 3 closed closed closed partially open open position End point I Area I Focus Area II Endpoint II

5 shows the coupling of a circuit by means of a four-way mixing valve described in this way MV.

The hydraulic system is optional with a throttle valve DV and two check valves ÜV2 and ÜV3 expanded. The throttle valve DV should be in both directions (return flow Q4 positive or negative) increase the pressure difference between the nodes K2 and K3 and can also without Moving parts are designed as a baffle plate or other cross-sectional constriction. The Check valves ÜV2 and ÜV3 act as non-return valves and are said to be parasitic Exclude circular flows.

The arrangement can advantageously be carried out in such a way that in FIG Individual components to form an assembly with six pipe connections and one actuator are summarized. The arrangement can thus be used as an industrially prefabricated accessory are provided and significantly reduces the on-site assembly work.

6 shows a variant with a wall-mounted heat generator WE1, in which the pump P1 for driving the direct heating circuit is integrated. In the case of heavy loads, i.e. at Q3 ≠ 0 and Q5 ≥ 0, a parasitic circuit current via the lines of the boiler flow Q1, Preventing the feed streams Q3 and Q5 and the boiler return Q4 is Feed current Q5 a check valve ÜV4 provided.

Claims (12)

Method for operating a circulating liquid heating or cooling system with a direct heating circuit which has a flow and a return line and is directly connected to the heat / cold generator and a mixer circuit which is connected in parallel with the flow and return lines of the direct heating circuit and is regulated by admixing its return, characterized in that that the following three operating states are possible: a) The mixer circuit is fed by the flow of the heat / cold generator, b) the mixer circuit is controlled by the flow of the heat / cold generator and the return of the direct heating circuit, c) the mixer circuit is fed by the return of the direct heating circuit. A method according to claim 1, characterized in that the mixer circuit at Low load exclusively fed by the return of the direct heating circuit and exclusively regulated by admixing its return and in the event of heavy load from the supply of the heat / cold generator and the return of the direct heating circuit and fed exclusively by Mixing these heat / cold flows is regulated. Circulation liquid heating or cooling with a direct heating circuit having a flow and a return line and a mixer circuit connected in parallel with the flow and return line of the direct heating circuit, which is equipped with a first controllable three-way mixing valve (MV1) for admixing the return of the mixer circuit, characterized in that the mixer circuit on the input side is connected to the flow and return lines of the direct heating circuit via a second controllable three-way mixing valve (MV2). Circulating liquid heating or cooling according to claim 3, characterized in that the Three-way mixing valves (MV1, MV2) by servomotors equipped with limit switches (M1, M2) can be operated. Circulating liquid heating or cooling according to claim 4, characterized in that the Actuators (M1, M2) are mutually locked by limit switches so that only after opening of the first three-way mixing valve (MV1) driven by a first servomotor (M1) Open the second three-way mixing valve driven by a second servomotor (M2) (MV2) and only after the second three-way mixing valve (MV2) has been closed of the first three-way mixing valve (MV1). Circulating liquid heating or cooling according to one of claims 3 to 5, characterized characterized in that the first and second three-way mixing valve (MV1, MV2) functionally too a four-way mixing valve (MV) with three inputs (1, 2, 3) and one output (4) as well an actuator are combined, with only the first (1) and the second (2) or the second (2) and the third entrance (3) can be open at the same time. Circulating liquid heating or cooling according to one of claims 3 to 6, characterized characterized in that the first three-way mixing valve (MV1) in the from the return of the A check valve (ÜV2) is arranged upstream of the mixer branching line. Circulating liquid heating or cooling according to one of claims 3 to 7, characterized characterized in that the second three-way mixing valve (MV2) in the from the inlet of the A check valve (ÜV3) is arranged upstream of the line branching the direct heating circuit. Circulating liquid heating or cooling according to one of claims 3 to 8, characterized characterized in that the second three-way mixing valve (MV2) in the from the return of the A check valve (ÜV4) is arranged upstream of the line branching the direct heating circuit. Circulating liquid heating or cooling according to one of claims 3 to 9, characterized characterized in that in the return of the direct heating circuit (Q4) between the connection of the Flow and return lines of the mixer circuit a throttle valve (DV) is arranged. Circulating liquid heating or cooling according to one of claims 6 to 10, characterized characterized in that the four-way mixing valve (MV), pipe connections for the pre and Return of the direct heating circuit, pipe connections for the supply and return of the mixer circuit and the connections of the direct and mixer circuits to form a unit with one Flow input, a flow output, a return input and a return output of the Direct heating circuit and a flow output and a return input of the mixer circuit are summarized. Circulating liquid heating or cooling according to claim 11, characterized in that at least one upstream of the inputs of the four-way mixing valve (MV) and / or check valve assigned to the flow of the direct heating circuit (ÜV1, ÜV2, ÜV3) and / or throttle valve (DV) assigned to the return of the direct heating circuit integrated in the unit is.

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