AT394261B - CONTROL DEVICE FOR A HEAT SOURCE - Google Patents

Description

AT 394 261 B

The present invention relates to a control device for a heat source of a central heating system with a first directly connected consumer circuit and a second consumer circuit connected via a mixing valve, a circulation pump and a setpoint device for different temperatures in the two consumer circuits.

Central heating systems have become known which have to feed several consumers which are at independent target temperatures. One should think of a domestic hot water tank to be charged by a central heating boiler while simultaneously feeding a radiator heating system or when feeding a radiator heating system from a boiler that is simultaneously connected to an underfloor heating system. For this purpose it has previously been customary to couple the consumer at the higher temperature level directly to the heat source, whereas the consumer at the lower temperature level is coupled via a mixing valve. Both heating circuits were controlled via a common flow temperature control, which usually contains a clock. It has become common to operate heating systems with night reductions, with a high day setpoint and a low night setpoint being specified in the clock, on which the two circuits are operated. According to the state of the art, only a joint lowering and raising of both heating circuits is possible.

This results in decisive disadvantages if, in particular, the lowering of the consumer circuit, which is at the higher temperature level, affects the heating circuit, which is in itself at a lower level, to the extent that its flow temperature has to be driven just higher than the heat source actually specifies.

The present invention is based on the object of avoiding this disadvantage and thus specifying the temperature setpoint for the connected consumer circuits that the consumer at the higher temperature level dictates the setpoint.

The object of the invention is that the higher of the two temperature setpoints is provided as a reference variable for the heat source.

It is thus possible to operate the heat source via the control device with the setpoint that is necessary for the two consumer circuits than the higher one. The consumer circuit, which requires a higher flow temperature setpoint, is then connected via the mixing valve.

In an embodiment of the invention, it is proposed that a setpoint comparator is provided, the output of which is connected to a solenoid valve in the fuel line of the heat source, and the inputs of which are connected to a setpoint processing element, each of which has a variable value with an outside temperature Heating curve slope value and the high or low temperature setpoints are switched.

This configuration makes it possible to achieve the task in a particularly simple manner, since the setpoint comparator makes it possible to compare the setpoints, which is provided as a reference variable for the heat source, and the comparator can then act directly on the solenoid valve that directly controls the energy supply to the heat source. By connecting the inputs of the comparator, each with a setpoint processing element, it is possible to process other necessary values in this measured value processing, e.g. B. co-process the outside temperature value, the heating curve steepness value and the setpoints of the two heating consumer circuits without the need for special circuit elements.

If separate pumps are present in the individual heating circuits, then, according to a further improvement of the invention, it is possible for each pump motor to be provided with a pump control element which is connected as a comparator, the first inputs of which are connected to the outside temperature sensor and the second inputs of which are setpoint adjusters are connected via time switch contacts. Individual control of several pumps is particularly easy to achieve.

Further refinements and particularly advantageous developments of the inventions can be seen from the following description, which explain an exemplary embodiment of the invention with reference to FIGS. 1 and 2 of the drawing:

Show it:

Figure 1 is a hydraulic schematic diagram of a central heating system and

Figure 2 is an electrical block diagram.

In both figures, the same reference numerals denote the same details.

A gas or oil-fired central heating boiler (1) - it could just as well be a gas-fired circulating water heater or an electric instantaneous water heater - is connected to a central heating system (4) via a flow line (2) and a return line (3). An electrical connection (5) to a supply network is also provided. The flow line (2) leads to a branch point (6) from which two consumer circuits (7 and 8) branch off. The first consumer circuit (8) is connected via a check valve (9) and a circulating pump (10), which has a drive motor (11), to a first consumer (12) to be operated at a relatively high temperature level, the rear connection (13) of which the return line (3) opens. This consumer (12) is either a domestic hot water tank that can be charged to a maximum temperature of 80 ° or a radiator network that then has a maximum temperature of approximately 60 ° in the flow. The flow line (2) of the first heating circuits (8) is provided with a contact temperature sensor (15), which is connected to a control unit (17) -2- b * ► via a measuring line (16)

AT 394 261 B The second heating circuit (7) connected to the branch point (6) has a flow line (18) in which a check valve (19) is provided, to which a 3-way mixing valve (20) connects , whose servomotor (21) can be adjusted by the control unit (17) via a control line (22). Instead of a 3-way mixing valve (20), a 4-way mixer could also be used. It does not matter whether it is a 5 mixing valve or a flap mixer.

An output of the mixing valve is connected to a bypass line (23) which leads directly to the return line (3). The forward flow line (18 ') is provided with a second circulation pump (24), the drive motor (25) of which is connected to the control unit (17) via a mains voltage supply line (26). A feed flow temperature sensor (27) is also provided on the flow line (18 ') and is coupled to the control unit (17) via a measurement line (28). A second consumer (29) is fed from the flow line (18 ') and is in any case at a usually lower temperature level than the consumer (12). If the consumer (12) is designed as a domestic hot water tank, the consumer (29) can use one Radiator heating system exist, the consumer (12) is itself designed as a radiator group, the consumer (29) can also be designed as a radiator group, which for some reason is then to be operated at a normally lower temperature level, the consumer (29) can also represent an underfloor heating system or part of such a system. On the return side, the consumer (29) is connected to the return line (3) via a line (30). The boiler is controlled by the control unit (17) via a line (31)

An outside temperature sensor (32) is connected to the control unit via a line (33), it is possible to connect a remote control unit (34) to the control unit (17) via a line (35) if the control unit (17) is, for example Boiler is assigned immediately adjacent and remote control is to be carried out from a room of the apartment to be heated.

The control device has two clocks (36 and 37) with which the day and night setpoints of the two heating circuits or the two consumers (12 and 29) can be controlled. It is also possible to do this with a clock if it only has different switching contacts.

The present invention is not limited to the control of a heat source for two heating circuits; there may also be a plurality of further heating circuits arranged in parallel which are at different temperatures. These in turn are then started up via a mixing valve each, and the supply lines behind the mixing valves are provided with temperature sensors, which are then connected in the manner described to the control unit 30 (17). It is then necessary to control the day and night setpoints of these additional consumer groups via separate clocks or via separate contact levels of a single clock.

The control unit has buttons (38) for the day setpoint of the first heating circuit, (39) for the night setpoint of the first heating circuit and (40) for the steepness of the heating curve of the first heating circuit and (41, 42 and 43) for the same values assigned to the second heating circuit. The mains voltage supply for the 35 pump motor (11) takes place via a line (44) which is looped through the heat source (1) and is connected to the line (31).

The control unit (17) is only explained in more detail in accordance with the illustration in FIG. 2. The control unit has a setpoint comparator (50) as the central element, the output (51) of which is connected to a flow temperature controller (52). The 40 current setpoint is given to the flow temperature controller via line (51). The flow temperature controller (52) is given the actual value as the flow temperature sensor sensed by the flow temperature sensor (15) via line (16). Due to the control deviation, a signal proportional to the control deviation arises at the output (53) of the flow temperature controller, which is also given to the solenoid valve (45), the heat source (1) and either switches on or off. It follows from this that the flow temperature controller is designed as a two-point controller, but this need not be the case. 45 Likewise, it is not necessary for the supply temperature to be regulated within the control system; in a technically equivalent way, a return temperature regulation or regulation of the differential temperature at the consumer could also take place.

The setpoint comparator (50) has two inputs (54 and 55), of which the input (54) is connected to the output of a setpoint processing element (56). The 50 heating curve slope adjuster (40) forms an input (57) thereof. A second input (58) of the setpoint processing element is connected to the line (33) of the outside temperature sensor (32). A third input (59) of the setpoint processing element is connected to the switching contact level (60) of the clock (36). This switching contact level switches either line (61) or line (62) with the day setpoint, set on the adjuster (38), or with the night setpoint, set on the adjuster (39), on line (59) through and blocks the other 55 lines.

Analogously, a second setpoint processing element (63) is provided, which is assigned to the second heating circuit (7). The output (64) of this setpoint processing element is on the one hand with the line (55) and on the other hand electrically in parallel with an input (65) of the Mixer controller (66) connected. The mixer controller is a flow temperature controller for the flow temperature of the second heating circuit. The measuring element for this is the flow temperature sensor (27) and the actuator is the position of the mixer (20). The command variable is supplied via line (65). In the output, the mixer controller has two lines (67 and 68) that lead to the drive motor (21) of the mixer (20) and either a slow cycle -3-

AT 394 261 B may result in the mixer opening or closing slowly.

A first input (69) of the setpoint processing element (63) is formed by the adjuster (43), which specifies the steepness of the heating curve for this second consumer circuit (7). A second input (70) is electrically connected in parallel to the line (33). A third input (71) leads to the switching contact level (72) of the second clock (37) which, depending on the switching position of its contacts, either connects the line (73 or 74) to the line (71). The line (73) is connected to the night value setpoint adjuster (42), the line (74) to the day setpoint adjuster (41).

A line (75) is also electrically connected in parallel to the line (33) and is connected to an input (76) of a first pump control element (77) which, via the line (44), the pump motor (11) of the pump (10) controlled. The second input (78) of the pump control element is coupled to the line (59). A second pump control element (79) is also provided, the output of which is connected to the line (26) and thus controls the pump motor (25) of the second heating circuit pump (24). An input (80) of the second pump control element (79) is electrically connected in parallel to the line (33), the second input (81) is coupled to the line (71) via a line (82).

The central heating system or its control described in FIGS. 1 and 2 has the following function: For the description it is assumed that the consumer (12) consists of a group of radiators, the individual radiators being assigned to specific rooms in a family home. The second consumer (29) consists of an underfloor heating system that is to supply heat to other rooms in this house. It can be assumed here that the flow temperature setpoint of the consumer (29) is lower than the flow temperature setpoint of the consumer (12) both during the day and at night. It should also be assumed that the consumer (12) is assigned, for example, to a separate apartment in this single-family house. In this way, the user of the granny flat specifies his individual program via the time switch (36) and the setpoint adjuster (38 to 40). Provided that, for reasons of economy or other motives, the granny wants a relatively early lowering of his heating circuit, e.g. at 9:00 p.m., or an early heating up of his heating circuit, e.g. at 5:30 a.m., he will mark the corresponding switchover points in the contact level of his watch. For the further description, it is assumed that the occupant of the main apartment in this house, i.e. the person who controls the heating circuit (29), does not want the night setpoint to be lowered until 10 p.m. and the day setpoint to be raised to 7.00 a.m. . If it is now assumed that the central heating system and therefore the boiler (1) are in operation and it is 5:00 p.m., both boiler circuits are supplied with the corresponding preset flow temperatures by the boiler, the flow temperatures are regulated, the first heating circuit having a control circuit, which consists of the sensor (15), the control unit (17) and, as an actuator, the solenoid valve (45) of the boiler (1). The control circuit of the second heating circuit (7) consists of the sensor (27), the control unit (17) and the mixer (20). If the first changeover command comes to the lower night setpoint through the clock (36), this would bring about a total lowering of both heating circuits in the prior art. In the invention, however, this setpoint is compared with the still high second setpoint of the second heating circuit (7). The two setpoints are applied via lines (54 and 64) to the setpoint comparator (50), which switches through the higher setpoint of the two. This means that the lowering request of one user is ignored and the heat source continues to work with the high setpoint of one heating circuit. It does not matter which of the two heating circuits or, in the case of a large number of heating circuits, which heating circuit the higher setpoint request is based on. Only when both heating circuits or, generally speaking, all heating circuits specify the reduction, is the heat source (1) driving a low total flow temperature. If after the end of the night reduction period only one setpoint of the two or many setpoints jumps back to the higher value, the setpoint comparator (50) gives the highest setpoint to the heat source temperature control. The further lowering requests from other heating circuits are suppressed.

The user of a heating circuit has the option, however, if he lowers the setpoint, i.e. by turning the buttons (39 or 42) below the actual temperature, so that the associated pump control element (77 or 79) suppresses the pump from continuing to run. The pump control elements (77 and 79) are themselves designed as comparators and compare the set room temperature via lines (78 and 82) with the actual outside temperature values via lines (33) and (75 and 80). This enables the associated consumer users to save a maximum of energy, including electrical energy for the associated pump motors, if this is desired.

It should also be noted that the term night setpoint generator can refer not only to night reductions but also to day reductions. What is meant is a desired reduction compared to a first high setpoint, no matter what time it is. -4-

Claims (3)

AT 394 261 B 5 PATENT CLAIMS 1. Control device for a heat source of a central heating system with a first directly connected consumer circuit and a second consumer circuit connected via a mixing valve, a circulation pump and a setpoint generator for different temperatures in the two consumer circuits, characterized in that the respective higher of the two temperature setpoints is provided as a reference variable for the heat source (1). 15 2. Control device according to claim 1, characterized in that a setpoint comparator (50) is provided, the output (51) is connected to a solenoid valve (45) in the fuel line of the heat source (1) and the inputs (54, 55) are each connected to a setpoint processing element (56, 63) to which a variable value with an outside temperature (32), a heating curve steepness value and the 20 high or low temperature setpoints are connected. 3. Control device according to claim 1, characterized in that for each pump motor (11, 25) a pump control member (77, 79) is provided, which is connected as a comparator, the first inputs (76, 80) with the outside temperature sensor (32) and whose second inputs (78, 80) are connected to the setpoint adjusters (38, 25 39, 41, 42) via time switch contacts (60, 72). 30 Including 2 sheets of drawings