DE3112220A1 - Method for operating a multivalent changeover switch for a multivalent heating system, and a multivalent changeover switch for carrying out the method - Google Patents

Description

SIEMENS AKTIENGESELLSCHAFT Our mark Berlin and Munich VPA 8t P 4 0 2 3 DE

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Method for operating a multi-level switch and multi-level switch for carrying out the method

The invention relates to a method for operating a multivalent switch for a multivalent heating system, the radiator through which a heat transfer medium flows, several heat sources for heating the heat transfer medium, by the multivalence switch depending on a temperature criterion can be switched on or off, as well as a control device for the temperature of the heat transfer medium.

The invention also relates to a multivalence switch for performing the method, the input side a temperature value is supplied, with a multiple switch that switches off or on, respectively causes a heat source.

Such a method and such a multivalue switch are known in heating system construction.

A multivalent heating system is one such to understand, which has at least two, but preferably more heat sources for heating the heat carrier. In many cases, one of the heat sources is designed as a boiler that can be heated with fossil fuels. At least one heat pump, which is an air-water heat pump, generally serves as a further heat source can be formed. Since an oversized heat pump is uneconomical at higher outside temperatures works, there is a greater tendency to either provide several heat pumps or only one heat pump to provide a step-by-step increase in motor or compressor output. If there is a boiler, This is used as the most powerful heat source in extreme SpI 2 Ste / 03/18/1981

Heat requests switched on as the last heat source. With low or medium heat requirements, the Required heat output by the heat pump or the heat pumps or different compressor stages of a Applied heat pump, wherein a heat pump is operated clocked.

The required heat output of the building to be heated by the heating system increases as it falls Outside temperature. The heat output of a heat pump, in particular that of an air-water heat pump, in which the ambient air is used as a heat reservoir, but drops as the outside temperature falls. Below one Critical outside temperature can therefore with several heat pumps one heat pump or with one heat pump these In the lowest level of compressor output, you can no longer generate the required heat output on your own. For this reason, it is necessary for a heating system that contains several heat pumps to install additional heat pumps or, in the case of a multi-stage heat pump, switch on an additional compressor stage or in the case of extreme heat requirements in the case of a heating system that contains a boiler, it can even be switched on. The heat sources then work in parallel. The switching on and off of heat sources is carried out by the multi-valence switch.

In conventional heating systems, additional heat sources are switched on depending on fixed outside temperature values. However, such fixed outside temperature values represent an unsatisfactory criterion for the connection of further heat sources, as there are significant influencing factors such as solar radiation or Wind speed, disregard. In addition to these weather conditions, the required heat output depends of a building also depends considerably on the shape and heat transfer coefficients of the building walls.

A rigid temperature criterion in the form of fixed external temperature values therefore leads to the further heat sources are put into operation too early and too often, resulting in avoidable energy waste leads.

The first object of the invention is to provide a method of the type mentioned at the outset, in which the A further heat source is only switched on when the required heat output is actually from the heat source in operation can no longer be applied. Further, the invention is second The object of the invention is to specify a multivalence switch of the type mentioned at the beginning, which enables the connection a further heat source is only effected when the required heat output no longer differs from the previous one in operation can be applied.

The first object is achieved according to the invention in that a further heat source is switched on, if a difference value falls below a fixed switch-on limit value of a first tolerance band, the Difference value represents the difference between a first and a second integration value and the first integration value takes place by temporal integration of a standard signal over the first time periods in which the actual temperature value of the heat transfer medium above the upper limit value of one containing the temperature setpoint second tolerance band and the second integration value by time integration of the standard signal takes place over the second time periods in which the actual temperature value of the heat transfer medium is below the lower limit of the second tolerance band. Because that A further heat source is only switched on when one is generated by subtracting two integration values Difference value the first limit value of a first tolerance band serving as a fixed switch-on limit value

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reached, whereby the integration time is made dependent on how long the actual temperature value of the heat transfer medium leaves the upper or lower limit value of a first tolerance band, too frequent, Short-term switching on of another heat source is avoided and only another heat source is used instead then switched on when the required heat output even with continuous operation of the previously switched on heat source or heat sources can no longer be provided.

An advantageous further development of the invention is that a heat source is switched off, when the difference value reaches a fixed switch-off limit value as the second limit value of the first tolerance band.

This ensures that there are no short-term reductions in the current heating power requirement result in only a short-term shutdown of a heat source that is in operation.

Another advantageous development of the method according to the invention consists in that each time of the switch-on limit value or the switch-off limit value, the difference value and the integration value an initial value can be reset. Thus, after switching on or switching off a heat source reproducible initial conditions are set for the next monitoring cycle, so that the history of the last monitoring cycle -: it no longer plays a role in the new monitoring cycle.

It is advantageous if the standard signal is a constant direct current. This ensures a high level of reproducibility of the desired process can be achieved with little effort.

Alternatively, the standard signal can be a sequence of pulses with the same voltage time area and the same frequency.

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The first and second integration values are then through Integration formed over the voltage-time areas of the pulses. Are pulses of equal voltage-time areas technically feasible with little effort. 5

In a preferred embodiment, the standard signal is with the current setpoint-actual value difference of the temperature of the heat carrier weighted. The method according to the invention is thus based to a greater extent on the current heat output deficit or the current heat output surplus.

It is advantageous if the temperature setpoint of the heat transfer medium by the control device as a time variable size is specified and if the limit values of the second tolerance band the changes in the temperature setpoint follow. In this case, in the control device the heating system uses the setpoint / actual value difference of a room temperature and / or the outside temperature.

A further improvement of the method according to the invention can thus be achieved, since it is even more sensitive to the current actually required heat output is turned off.

It is advantageous here if the temperature setpoint is in the middle of the second tolerance band. So lie the upper and lower limit values of the second tolerance band symmetrically to the temperature setpoint, so that the Beginning of the first and the second time period in the same way from a momentary heat output deficit or Heat output is dependent on excess.

The second task is given in the case of a multivalue switch of the type mentioned at the beginning with additional consideration the point of view of a no longer rigid outside temperature, but flexible shutdown behavior

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a heat source solved in that for specifying the first and the second tolerance band each a first and a second threshold value element is provided, each with two different limit values, the upper or the lower limit value of the first threshold value element corresponds to the abstention limit value or the switch-on limit value and the output signal of the first threshold value element that occurs when the switch-off limit value is reached, to one Control input and that when the switch-on limit value is reached resulting output signal to the other control input a controllable multiple switch is fed to the second threshold element, the input side at least the actual temperature value of the heat transfer medium is supplied, a first during the first period of time Signal and supplies a second signal during the second period and that a signal generator for generating of the standard signal is provided, which - influenced by the first and the second signal - at least one an integrator having an integration device is supplied, which supplies the difference value on the output side, which is fed to the first threshold value element, wherein the integration device uses the difference value as Difference between the waiting time for all the first signals and that for the waiting time for all the second signals Integration of the standard signal obtained integration values. Such an arrangement can be made commercially available, known functional elements are built. In addition to being constructed from discrete or integrated functional elements, such a multi-valence switch also be created in the form of a microcomputer. This is particularly advantageous if the control device is already there the heating system is created using a microcomputer. This already existing The microcomputer can then additionally function as the multivalue switch to carry out the inventive Procedure.

To determine the difference value and the integration values when the switch-on limit value or the switch-off limit value is reached to reset to an initial value, the integration device can have a reset input, to which the output signal of the first threshold value element is fed.

An advantageous development of the multivalence switch in which the standard signal is a constant direct current is that a constant current source is used to specify the standard signal, which is on the output side provides a first and a second constant current signal, the second constant current signal being inverted of the first constant current signal is obtained, and that the integration means a first, by the first signal of the second threshold member influenced controllable switch via which the first Constant current signal is carried, and has a second controllable switch influenced by the second signal, via which the second constant current signal is passed, the outputs of both controllable switches on the input of the integrator are connected and the reset input of the integration device through a reset input of the integrator is formed.

A multivalence switch that can be produced from simple components and that with analog values is specified is working.

Tine alternative simplified embodiment of a operating with analog values Multivalenzumschalters is that the second threshold value circuit is additionally the signal generator and that the first signal supplied to the input of the integration means of the second threshold element in this via a first resistor and the second signal via an inverter and a second resistor are jointly fed to the input of an integrator, the reset input

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the integration device is formed by a reset input of the integrator. This eliminates the need for a separate one Signal generator. Instead, the first and the second signal, which in this case are of the same size and of should be of the same polarity, converted into current values that can be easily integrated.

An advantageous further development of the penultimate multivalue switch, in which the standard signal with the current setpoint-actual value difference of the temperature of the Heat carrier is weighted, consists in that instead of the constant current source, a controllable current generator is used with a control input whose output current signal is proportional to that present at the control input The absolute value of the setpoint-actual value difference of the temperature of the heat transfer medium is.

An advantageous alternative embodiment of a multivalue switch, in which the standard signal with the current setpoint-actual value difference of the temperature of the Heat carrier is weighted, consists in that the input of the integrator is preceded by a multiplier is to which the absolute value of the setpoint / actual value difference of the temperature of the heat transfer medium is also fed.

An advantageous one that works with digital signals Embodiment of a multivalue switch exists in that a first and a second triggerable pulse generator is provided instead of the signal generator, being the trigger input of the first pulse generator the first signal of the second threshold value element and the trigger input of the second pulse generator the second Signal of the second threshold value element is supplied that a forward-backward counter is provided as an integrator whose up count input is the output signal of the first pulse generator and its countdown input the output signal of the second pulse generator

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is performed and that the reset input of the up-down counter is acted upon by the output signal of the threshold value element ".

An advantageous development of a digital signal processing Multiva "bilge regulator, in which the standard signal with the current setpoint-actual value difference of the Temperature of the heat carrier is weighted, consists in that a difference value generator is provided, the input side the setpoint and the actual value of the temperature of the heat transfer medium is supplied and an absolute value generator and an analog-digital converter are connected downstream is that in the integration device two triggerable adders with reset input for digital values are provided, to whose adding input the analog-digital converter is connected, the trigger input of the first adder to the output of the first pulse generator and the trigger input of the second Adder is connected to the output of the second pulse generator, and that the first adder to the up count input and da3 second adder to the down counting input of the up / down counter is connected and that the reset inputs of the two adders with the output signal of the first threshold value element are applied. The adders used here are those which each when a trigger pulse is received, the one at your Adding input pending digital value to the. add the total value already accumulated in the memory Embodiments of the multivalue switch capable of processing digital values are particularly suitable good for implementation by a microcomputer.

A preferred embodiment of a multivalence controller, at which the temperature setpoint of the heat transfer medium through the Control device is specified as a variable over time and the limit values of the second tolerance band

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Changes in the temperature setpoint follow, consists in that the input of the second threshold value element the temperature setpoint of the heat transfer medium is supplied. Known threshold value elements are used here, the limit values of which are determined by a control signal on the input side be raised or lowered in the same way.

The invention is explained in more detail below with reference to exemplary embodiments in FIGS. Included shows:

1 shows a basic illustration of the heating system, FIG. 2 shows a first exemplary embodiment of an analog working bivalve holder to carry out of the method according to the invention, FIG. 3 shows a signal diagram to illustrate the

Mode of operation of the dual mode switch shown in FIG and the method, FIG. 4 shows a second exemplary embodiment of an analog

working dual mode switch and FIG. 5 shows a third exemplary embodiment in the form of a digitally working dual mode switch.

In Fig. 1, a conventional heating system is shown with the reference character A, in the context of a after bivalence switch operated according to the method according to the invention B can be used. The reference numeral 1 denotes the heat pump, which in the exemplary embodiment is designed as an air-water heat pump. One The heat output of the heat pump is strongly dependent on the outside temperature only with such air-water heat pumps whereas the heat output of heat pumps, which extract energy from the groundwater, is seasonal show small fluctuations in heat output.

The heat pump 1 has two compressor stages V1 and V2, with the

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density level V1 is operated clocked. Occurs an increased Heating power demand on, even with continuous operation the compressor stage V1 can no longer be satisfied, is under the action of the dual mode switch B also switched on the second Verdxchterstufe V2, which is now operated in a clocked manner. If there is an even higher heating power requirement, which even with continuous operation of the two compressor stages V1 and V2 can no longer be satisfied by the heat pump 1, under the influence of the Bivalenzumscharters B Finally, the boiler 2 is also switched on, with the heat pump 1 now using instead of the clocking the motor-operated mixing valve 4 the control difference between the actual temperature value & Lund setpoint ^ s des Heat carrier is regulated.

Only one of the radiators is shown as an example and given the reference number 3. In the im Heating return arranged heat pump 1, the water serving as a heat transfer medium is heated and via the as A four-way valve designed mixing valve 4 and the circulating pump 5 are fed back into the radiator 2. Heat pump 1, Radiator 3, mixing valve 4, environmental pump 5 and the connecting pipes 6 form the heating circuit H. Als Actual value ^ i of the temperature of the heat transfer medium is used for the temperature of the heating flow determined by the flow temperature sensor 7 is detected.

The most powerful heat source is the boiler 2, which is preferably heated by a fossil fuel will. This boiler 2 contains an internal control that ensures that a predetermined temperature of the heat transfer medium in the boiler is maintained. When boiler 2 is in operation, the heated heat transfer medium flows to the connection c of the mixing valve 4, whereas from the connection d of the Mixing valve 3 depending on the position of the mixing valve

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a more or less large proportion of the heat transfer medium flowing into the connection a from the heat pump 1 is branched off. The connection b of the mixing valve 4 supplies the heating flow.
5

In one end position of the mixing valve 4 which can be actuated by the servomotor 8, the two are each for themselves Connections a and b, or connections c and d are connected to one another. In this case the boiler is 2 decoupled from heating circuit H. The heat transfer medium located in the boiler 2 is then via the connection c des Mixing valve 4 is connected directly to port d without a branch.

If the mixing valve 4 leaves the end position described, a part of the flowing in via the connection a is through the heat pump 1 of the heated heat transfer medium branched off via the connection d to the boiler 2, whereas the remainder Portion of the heat transfer medium flowing in via connection a flows out directly via connection b. Via the connection c a portion of the 'heat transfer medium heated in boiler 2 also flows into port b. The latter Case in which the heat pump 1 and the boiler 2 work and together provide the required heat output, is called parallel operation. It only takes place if the required heat output is not only short-term cannot be applied by the two compressor stages V1 and V2 of the heat pump 1 alone.

To operate the heating system A, a control device 9 is provided which, as function blocks, is a heat pump control 10, a controller 11 for the boiler 2, a heating controller 12 and the bivalence switch r B has.

If the heating power requirement is relatively low, the boiler 2 and the second compressor stage are V2

of the heat pump 1 out of operation and the first compressor stage V1 of the heat pump 1 can - controlled by the heat pump controller 10 in cooperation with the heating controller 12 - already generate the required heat output in intermittent operation. As the heating power requirement increases, the shutdown pauses in compressor stage V1 become shorter and shorter until it finally has to run permanently in order to meet the heat requirement. A further increase in the heat output emitted by the compressor stage V1 can now no longer be achieved. If the required heat output continues to rise, for example due to a drop in outside temperature, this is detected in the bivalence switch B operating according to the method according to the invention, whereupon a signal v1 + v2 appears at its output instead of the previous signal v1, which means that the second one is switched on via the heat pump controller 10 Compressor stage V2 is initiated. Under the action of the heating controller 12, which, for example, by evaluating a heating curve, converts the outside temperature & A of the outside temperature sensor 15 into a temperature setpoint & s for the heat transfer medium and compares it with the actual temperature value - ^ id of the heat transfer medium supplied by the flow temperature sensor, the second compressor stage V2 of the heat pump is now operated in a pulsed manner 1, as a result of which an increased output power of the heat pump 1 is now available for heating the heat carrier. If the required heat output increases even further, so that it can no longer be satisfied even with permanent operation of both compressor stages V1 and V2 of heat pump 1, this is recognized in bivalent switch B, whereupon a signal v1 + v2 + HK appears at its output, whereby the commissioning of the boiler is initiated via the controller 11 for the boiler 2. Under the action of the heating controller 13, which - as already mentioned - converts the outside temperature value & A of the outside temperature sensor 15 into a temperature setpoint ^ s for, for example, by evaluating a heating curve

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sets the heat transfer medium and compares it with the actual temperature value ^ i of the heat transfer medium supplied by the flow temperature sensor 7, the mixing valve 4 is now actuated by the servomotor 8, whereby the heat transfer medium already heated by the two compressor stages V1 and V2 of the heat pump 1 in the mixing valve 4 also receives hot boiler water is admixed. The control deviation A ^ = vi - / 5 "s of the heating flow 3 can thus be regulated. If the required heat output decreases again, the servomotor 8, under the influence of the heating controller 13, will finally bring the mixing valve 4 into its end position in which the boiler 2 is decoupled from the heating circuit H. The two compressor stages V1 and V2 of the heat pump 1 are still in continuous operation, since only the last connected heat source is clocked or, in the case of the boiler, controlled by adjusting the mixing valve 4 to compensate for the control deviation £>< ■ $ "- / 9 * i -3s is used. If the heat output of the non-cycled compressor stages is too high in relation to the required heat output, the actual temperature value of the heat transfer medium increases too much, whereupon the boiler is switched off by the multivalence switch B. The second compressor stage V2 is then operated in a clocked manner.

In order to avoid a too rapid oscillation between the switched-on state and the switched-off state of boiler 2, a minimum running time of e.g. one hour can be provided for this.

In the following, an exemplary embodiment will be given with reference to FIGS. 2 and 3 of the bivalence switch B according to the invention and the method according to the invention are explained in more detail will.

As already mentioned, the heating controller 13 regulates the actual temperature value λ? 1 of the heat transfer medium in the usual way

to a corresponding temperature setpoint ^ * s. In the exemplary embodiment, the flow temperature of the heat transfer medium, which is detected by the flow temperature sensor 7, is selected as the actual temperature value <\? 1. However, the return temperature can also be recorded and evaluated in the same way. As already explained, the temperature setpoint a? S can be derived from the outside temperature * &&. or the temperature-setpoint-actual value deviation vzs - - & z ± of a temperature-determining room or from a combination of both values. The deviation of the actual temperature value -v ^ i from the setpoint 4 "S of the heat carrier is, if constant flow is assumed, proportional to the momentarily missing heating output If you run the base load in continuous operation, there will always be a momentary excess or deficit in the heating output. As long as all the heat sources in operation (m) are sufficient and (m - 1) heat sources are not sufficient to cover the required heating output the time average of the current deficit or the excess of heating power L be zero; t + T

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25th

A deviation of the mean value L to one side or the other requires an activation or deactivation of Heat sources. Time averaging and time sales relative to the limits of a first tolerance band, a new type of switchover criterion is now formed worried by the bivalence switch B according to the invention.

The dual mode switch B shown in FIG. 2 has, among other things, a first threshold value element 14 for fixing a first tolerance band T1 and a second threshold value element 15, which is a second tolerance band

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T2 defines. The tolerance band T2 specified by the second threshold value element is limited by a lower limit value ^ 1 and an upper limit value ^ 2. These two limit values oH and / $ 2 include a temperature setpoint ^ s. In a heating system in which the temperature setpoint ^ s of the heat transfer medium is subject to only slight fluctuations over time, this can be specified as a constant value. In general, however, the temperature setpoint t9 "s of the heat transfer medium is set by the heating controller 12 as a function of the control difference \ ^ _ - Φ- of a temperature-determining room and /

ZS ZX

or the outside temperature ν * Α and have larger fluctuations over time. In this latter case, this temperature setpoint Φ is fed to the second threshold value element 15 on the input side. This is shown in Fig. 2 by the arrow labeled a ^ s. The second threshold element 15 is designed in this case so that the upper and lower limit values i9 ~ 1 and ^ 2 shift in the same sense as this time-variable temperature setpoint S "s , so that the value is always in the middle between the upper and the lower limit -θΊ and / § "2 is. In addition, the temperature actual value Φι of the heat transfer medium detected by the flow temperature sensor 7 is fed to the second threshold value element 15 on the input side.

The threshold value element 15 supplies a first signal W1 at one output and at a further output second signal W2, the first signal W1 always occurring when the actual temperature value $ i of the heat transfer medium is above the upper limit value ν 2, and the second .Signal W2 always arises when the actual temperature value ^ i has exceeded the lower limit value 'per cent. This is on lines 1 through 3 of the signal diagram in Fig. 3 shown. In the exemplary embodiment, the two signals W1 and W2 each represent DC voltage values, the duration of the first and the second time period

is fixed. Furthermore "includes the bivalence switch B as a signal generator 16 a power source, the output side supplies the two current signals 1+ and I-. The two current signals 1+ and I- sine in the simplest case two constant currents of the same amplitude, but different direction of current flow. It is more pleasant, however, these currents with the absolute value of the current control deviation IΔ £ H-I $ 1 - ^ s! the temperature of the medium to weight. For this purpose, the signal generator 16 is a controllable current generator with a control input formed at which the absolute value of the specified control difference is present. The output currents 1+ and I- are in in this case proportional to | A $ l. This is shown in dashed lines in FIG drawn.

The bivalence switch B also contains an integration device 18. The integration device 18 has a first and a second controllable switch 19 and 20, the outputs of which are mutually connected to the integration input of an integrator 21 provided with a reset input R. The input of the first controllable switch 19 is the current signal I +, the input of the second controllable switch 20 is the current signal I-. The first signal V / 1 is used to control the first controllable switch 19, the second signal ΊΙ2 is used to control the second controllable switch 20, each of these two controllable switches 19 and 20 being closed when the signal ¥ at its control input 1 or W2 is active. The two controllable switches 19 and 20 can therefore never be closed at the same time. The two current values 1+ and I- represent the standard signal. If the first controllable switch 19 is closed during a first period, upward integration takes place in integrator 21, whereas when the second switch 20 is closed, downward integration takes place during the second time period. The in-

grationseinrichtuiig 18 thus serves to form a Difference value from a first and a second integration value, the first integration value being the sum of all upward integrations and the second integration value represents the sum of all downward integrations. Of the The difference value D occurring at the output of the integrator 21 forms the output signal of the integration device 18 and is fed to the input of the first threshold value element 14.

The first threshold value element 14 sets the first tolerance band T1 between the first limit value -Z and the second limit value + Z specified. The first and second limit values -Z and + Z are symmetrical about the zero point arranged and represent fixed values. In the first threshold value element 14, the time course of the difference value on the input side in relation to the first and second limit value + Z and -Z monitored, the first limit value -Z as a switch-on limit value for a further heat generator and the second limit value + Z act as the same switch-off limit value. The threshold term 14 has two outputs, with a - for example, pulse-shaped - signal 11 then occurring at one output, if the difference value D is the lower switch-on limit value; -Z reached. At the second exit of the First threshold value element 14 always occurs, for example, a pulse-shaped signal 12 when the Difference value D reaches the second limit value + Z serving as the switch-off limit value. This is on the lines 4, 5 and 6 of the signal diagram in FIG.

The two outputs carrying signals 11 and 12 of the first threshold element 14 are led to the inputs of an OR gate 22, the output of which with the Reset input R of the integrator 21 is connected.

This means that whenever the difference value D exceeds either the switch-on limit value -Z or the switch-off limit value + Z

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reached, the integrator 21 is reset to zero, so that defined initial conditions for the following measuring cycle are present.

In addition, the output of the first threshold value element ΛL- carrying the signal 11 is fed to one control input a and the second output of the first threshold value element Λ ¹ - * carrying the signal 12 is fed to the second control input b of a controllable multiple switch 23. When a signal 11 occurs at the control input a, the switching finger 24 of the controllable multiple switch 23 moves one switching notch clockwise, whereas when a signal 12 occurs at the input b, the switching finger 24 moves one switching notch counterclockwise. In this way, the signal 11 in each case causes a heat source to be switched on, whereas when a signal 12 occurs, one of several heat sources in operation is switched off. Gate circuits 25, 26 can be inserted between the outputs of the first threshold value element 14 and the control inputs of the multiple switch 23 - as indicated by dashed lines - which allow the signal passage to be blocked under certain conditions and thus the controllable multiple switch 23 to its previous switch position " although one of the signals is left 11 or 12 active. This is for example in systemic jumps of temperature setpoint '\ 9 _»g of tfärmeträgers the case, as $ occur in the start after a night set the temperature set point *. the gate ^ 25 and 26 can be implemented with little effort, for example, by AND gates.

If the gates 25 and 26 are closed, is through the signal 11 in the case of the embodiment shown in FIG instead of the previous signal v1 + v2, the signal v1 + v2 + HK is now generated, whereby additional

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lent the boiler in operation as an additional heat source is set. In the case of the exemplary embodiment shown in FIG. 2, instead of the previous signal v1 + v2 now the signal v1 arise, whereby the previously in clocked operation second compressor stage V2 of the heat pump 1 is switched off.

The further embodiment shown in FIG. 4 represents a simplified bivalence switch B, which differs from the one explained above only in a simpler design of the integration ^{device 18 in the form of the integration device 18 f} and the waiver of the signal generator 16 made possible thereby. Functional elements that correspond to those explained in connection with FIG. 2 have been given the same reference numerals. The exemplary embodiment shown in FIG. 4 is based on the consideration that the second threshold value element 15 can also be used to generate the standard signal. The first and second signals W1 and W2, which specify the first and second time periods and which represent DC voltage blocks of the same polarity and amplitude extending over the duration of each first and second time period, form the standard signal for forming the first and second integration value. In this case, the signal W1 in the integration device 18 'is fed to the input of the integrator via a first resistor 27 and the second signal W2 is fed to the input of the integrator via an inverter 28 and a second resistor 29. The resistors 27 and 29 convert the voltage block of the signal W1 and the inverted voltage block of the second signal W2 into current blocks of the same amplitude but opposite current flow direction, so that all of the current blocks resulting from a first signal W1 are integrated upwards in the integrator 21, whereas all of them are from one second

Signal W2 resulting stream blocks integrated downwards will. The result of this is that the desired difference value D arises at the output of the integrator 21.

Is the weighting caused in FIG. 2 by the control input 17 of the signal generator 16 also in the case of the embodiment shown in Fig. 4 is desired, the input of the integrator 21 must be a multiplier 30 are connected upstream, whose one multiplication input is connected to the two resistors 27 and 29 and its second multiplication input with the absolute value of the control difference δ "θ" I = l $ i - ^ sJ the Temperature of the heat transfer medium is applied.

In Fig. 5 is a digital-based dual mode switch B shown for carrying out the method according to the invention. The functional elements which correspond to those used in FIGS. 2 and 4, corresponding reference numerals. With only effective Corresponding functional elements is the reference symbol used in the preceding figures provided with a double apostrophe.

The first and second signals W1 and W2 are each fed to the trigger input T of a first and second pulse generator 31 and 32. Each of these pulse generators 31 and 32 provides a pulse train consisting of square pulses I + ^ft or I - '' on the output side for the duration of a first or second period of time the first and second time periods, respectively. The first and the second pulse generator 31 and 32 serve as a signal generator 16 ″. The output signal I + ^{11 of} the first pulse generator 31 is applied to the trigger input T of a first triggerable adder 33 for numeric represented in digital form.

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values. The output of the second pulse generator 32 is also connected to the trigger input of a similar one Adder 34 connected. The adders 33 and 34 are constructed so that they are triggered when the numerical value currently present at the adding input + to a numerical value already present in a memory add

For weighting the standard signal present in the form of the output-side pulse trains I + ^1f and I- '· of the pulse generators 31 and 32, a differential value generator 35 is provided, to which the actual temperature value ■ $ i and the temperature setpoint value ^ s of the heat transfer medium are fed on the input side. In the difference value generator 35, an absolute value generator 36 is connected downstream, the analog output signal of which is converted in an analog-digital converter 37 into a digital value, for example in the BCD code. The digital output value of the analog-to-digital converter 37 is fed to the adding input + of each of the adding elements 33 and. In this way, the memory contents of the first and second adders 33 and 34 are incremented by the current absolute value of the control deviation A $ ~ when a pulse is received at the trigger input T. The current sum value is available at the output of the adders 33 and 34. The first and the second adders 33 and 34 thus each contain the current first and second integration values S1 and S2. The output of the first adder 33 is fed to the up-counting input v, the output of the second adder 34 to the down-counting input r of an up-down counter 21 '. The up / down counter 21 'can be designed to be triggerable. For this purpose, its trigger input T can, for example, be fed the two output signals of the first and second pulse generators 31 and 32 linked via an OR gate, the triggering taking place in each case with the falling edge of the individual pulses. Here is

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assumes that the triggering of the adders 33 and 3 ^ · in each case with a rising edge of the pulses originating from the pulse generators 31 and 32 takes place. The adders 33 and 34 and the up / down counter 21 ^ff together form the integration device 18 ″. The current difference value D from the difference between the first and second integration values S1 and S2 occurring at the output of the up / down counter 21 ^{! L is available in digital form at the input;} of a digital first threshold value element 14 ″. In the threshold value element 14 ″, the difference value is checked for leaving the first tolerance band T1 determined by the switch-on limit value -Z and the absolute limit value + Z. If the difference value D reaches the switch-on limit value -Z, the signal 11 is produced at the output of the first threshold value element 14 ″, whereas when the switch-off limit value + Z is reached at the second output of the first threshold value element I4 ^f ', the signal 12 which causes a heat source to be switched off is produced. As in the previous examples, signals 11 and 12 are disjunctively linked by OR gate 22 and used to reset integration device 18 ″. For this purpose, the output of the OR gate 22 is fed both to the reset input R of the up / down counter 21 ″ and to the reset inputs R of the two adders 33 and 34.

The first adder 33 thus contains the sum of the absolute values of all control deviations A ^ during all of the first Time spans since the last actuation of the controllable switch 23, whereas in the adder 34 the sum the absolute values of all system deviations Δ ^ - during of all second periods during the same period. These sums correspond to the first and second Integration value S1 and S2. The difference D of these Integration values S1 - S2 provide information about whether in the period since the last actuation of the controllable Switch 23 the required heating power requirement

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could be satisfied by the heat sources in operation within the first tolerance band T1 defined by the switch-on limit value -Z and the switch-off limit value + Z. The fluctuation range specified by the limit values -Z and + Z must be greater than the system-related fluctuation of the difference value D, which is proportional to the change in heating output of the clocked heat source in operation. If the weighting of the standard signal emitted by the two pulse generators 31 and 32 is to be dispensed with, then the difference value generator 35, the absolute value generator 36, the analog-digital converter 37 and the two adders 33 and 34 can be dispensed with. In this case, the output-side pulse trains I + ¹¹ and I- ' ^{1 of} the first and second pulse generators 31 and 32 are to be fed directly to the up-counting input ν and the down-counting input r of the up-down counter 21 ″. The controllable multiple switch 23 is actuated if a heat demand is not satisfied within a time determined by the two limit values -Z and + Z or an excess of heating output cannot be reduced sufficiently quickly.

The embodiment of a dual mode switch shown in FIG. 5 B is particularly suitable for implementation by a microcomputer.

18 claims
5 figures

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Claims (1)

Claims A method for operating a multivalent heating system for a multivalent heating system which has a heating element through which a heat transfer medium flows, several heat sources for heating the heat transfer medium, which are switched on or off by the multivalence switch depending on a temperature criterion, as well as a control device for the temperature of the heat transfer medium that a further heat source (V1, V2, 2) is switched on when a difference value (D) reaches a fixed switch-on limit value (-Z) as the first limit value of a first tolerance band (T1), the difference value (D) being the difference ( S1-S2) represents a first and a second integration value (S1, S2) and the first integration value is carried out by temporal integration of a standard signal (I +, W1, I + ¹¹ ) over the first time periods in which the actual temperature value ($ L) of the heat carrier is above the upper limit value (λ? 2) of a temperature setpoint (/ fts) containing z wide tolerance band (T2), and the second integration value (S2) takes place through temporal integration of the standard signal (I-, W2, I- ¹¹ ) over the second time periods in which the actual temperature value (Si) of the heat transfer medium is below the lower limit value (1 ) of the second tolerance band (T2) (Fig. 3, Fig. 5) ?. Method according to Claim 1, characterized in that that a heat source (V1, V2, 2) is switched off when the difference value (D) a fixed switch-off limit value (+ Z) is reached as the second limit value of the first tolerance band (T1). 3. The method according to claim 1 or 2, characterized in that in each case upon reaching the switch-on limit value (-Z) or the switch-off limit value VPA 81 P40 23 DE (+ Z) the difference value (D) and the integration values (S1, S2) can be reset to an initial value (O). 4. The method according to any one of claims 1 Ms 3, characterized in that the standard signal is a constant direct current (I +, I-). 5. The method according to any one of claims 1 Ms 3 »characterized in that the standard ^{signal is a sequence of pulses (I- 11} , I + ¹¹ ) of the same voltage time area and the same frequency. 6. The method according to any one of claims 1 to 3 »characterized in that the standard signal (I +, I-, I + ¹¹ , I- ¹¹ ) with the current setpoint-actual value difference (& $ =" θι - O ~ s) the Temperature of the heat carrier is weighted. 7. The method according to any one of claims 1 Ms 6, characterized in that the temperature setpoint (s $ s) of the heat transfer medium is specified by the control device (12) as a variable over time and that the limit values (^ 1, ^ 2) of the second tolerance band (T2) correspond to changes in the temperature setpoint ( # 33) follow. 8. The method according to any one of claims 1 to 7t characterized in that the temperature setpoint C $ s) is in the middle of the second tolerance band (T2). 9. Multivalence switch for performing the method according to claim 1 or 2, the input side a temperature value is supplied, with a multiple switch that switches off or on each heat source causes, characterized that for specifying the first and second tolerance "Bandes (T1, T2) a first or second threshold value ^{element (14, I4 fl} ; 15) each with two different limit values (-Z, + Z; - ^ 1. ^ 2) is provided, the upper and lower limit value (+ Z, -Z) of the first threshold value element (14, I4 ^ft ) corresponds to the switch-off limit value or the switch-on limit value and the output signal (12) of the first threshold value element (14, 14 '') that occurs when the switch-off limit value a (Z) is reached, corresponds to the one control input (b) and the output signal (11) that arises when the switch-on limit value (-Z) is reached is fed to the other control input (a) of a controllable multiple switch (23) so that the second threshold value element (15) supplies at least the actual temperature value (vi) of the heat transfer medium on the input side is supplied, supplies a first signal (¥ 1) during the first time period and a second signal (¥ 2) during the second time period, and that a signal generator (16, 15, 16 · ') for generating the standard signal (I +, I- , I + ' ¹ , I- ¹ ') is provided because s - influenced by the first and the second signal (¥ 1, ¥ 2) - is fed to an integration device (18, 18 ', 18'') which has at least one integrator (21, 21 ") and which outputs the difference value (D ), which is fed to the first threshold value element (14, 14 * ^f ), the integration device (18, 18 ', 18'') providing the difference value (D) as the difference between the while all first signals (¥ 1) and the forms the integration value (S1, S2) obtained while all second signals (¥ 2) are pending by integrating the standard signal (I +, I-, I + ' ¹ , I- ^11). 10. Multivalence switch according to claim 9 for performing the method according to claim 3, characterized characterized in that the integration device (18, 18 ', 18 ") has a reset input (R) to which the output signal (11, 12) of the first threshold value element (14, 14 '') is supplied. - 2θ— VPA 8t Ρ40 23 DE 11. Multivalence switch according to claims 9 and 10 for carrying out the method according to claim 4, characterized in that for Default of the standard signal from a constant current source (16) serves, which on the output side supplies a first and a second constant current signal (I +, I-), the second Constant current signal (I-) by inverting the first Constant current signal (1+) is obtained, and that the integration device (18) a first, influenced by the first signal (¥ 1) of the second threshold value element (15) has controllable switch (19) through which the first constant current signal (1+) is passed, and one second, by the second signal (¥ 2) influenced controllable switch (20) via which the second constant current signal (I-) is performed, the outputs of both controllable switches (19, 20) to the input of the Integrator (21) are connected and wherein the reset input of the integration device (18) by a Reset input (R) of the integrator (21) is formed (Fig. 2). 12. Multivalence switch according to claims 9 and 10 for performing the method according to claim 4, characterized in that the second threshold value element (15) additionally represents the signal generator (16) and that the input of the Integration device (18) supplied first signal (¥ 1) of the second threshold value element (15) in this over a first ¥ resistance (27) and the second signal (¥ 2) via an inverter (28) and a second ¥ resistance (29) are fed together to the input of the integrator (21), the reset input of the integration device (18) is formed by a reset input (R) of the integrator (21) (Fig. 4). 13 · Multi-valence switch according to claim 11 for implementation of the method according to claim 6, characterized -S- _ ^ 9-_ VPA 81 P 4 0 2 3 DE characterized in that instead of the constant current source (16) a controllable current generator (16) with a control input (17) is used, the output current signal of which (I +, I-) proportional to the absolute value of the setpoint / actual value difference at the control input (17) (ΐΔ ^ ν) = | λ5 i -a9s!) the temperature of the The heat transfer medium is (Fig. 2). 14.Multivalenzumsehalter according to claim 12 for implementation of the method according to claim 6, characterized in that the input of the integrator (21) is preceded by a multiplier (30), which also contains the absolute value of the setpoint / actual value difference (lA'frUj & i · - $ s |) the temperature of the heat carrier is supplied (Fig. 4). 15. Multivalence switch according to claims 9 and 10 for performing the method according to claim 5, characterized in that instead of the signal generator (16) a first and a second triggerable pulse generator (31, 32) is provided, the trigger input (T) of the first Pulse generator (31) the first signal (W1) of the second threshold value element (15) and the trigger input (T) of the second threshold value element (15) and the trigger input (T) of the second pulse generator (32) the second signal (W2) of the second threshold value element (15) is supplied that an up-down counter (21 '') is provided as an integrator, whose up-counting input (v) the output signal (I + ¹¹ ) of the first pulse generator (31) and its down-counting input (r) the output signal (I- '') of the second pulse generator (32) is supplied and that the reset input (R) of the up-down counter (21 ") with the output signal (11, V, 12) of the first threshold value element (I4 ^ft ) beau f is shown (Fig. 5). - -3e- VPA 81 P 4 0 2 3 DE 16. Multivalence switch according to claim 15 for carrying out the method according to claim 6, characterized in that a differential value generator (35) is provided to which the target value G $ s) and the actual value ("9i) of the temperature of the heat carrier are fed on the input side and to which a absolute value (36) and an analog-to-digital converter is connected downstream, in that in the integration means (18 ¹¹⁾ has two triggerable adders (33, 34) are provided with a reset input (R) of digital values, on whose adding input (+) of the analog-to-digital -Converter (37) is connected, the trigger input (T) of the first adder (33) to the output of the first pulse generator (31) and the trigger input (T) of the second adder (34) to the output of the second pulse generator (32) is connected that the first adder (33) is connected to the up-counting input (v) and the second adder (34) is connected to the down-counting input (r) of the up-down counter (21 '') and that the reset inputs (R) of the two adders (33, 34) have the output signal (11, V, 12) of the first threshold value element (14 ") applied to them (Fig. 5). 17. Multivalence switch according to one of claims 1 to 16 for performing the method according to claim 7, characterized in that the input of the second threshold value element (15) is the temperature setpoint (- ^ s) of the heat transfer medium is supplied. 18. Multivalence switch according to one of claims 9, 15, 16 or 17, characterized in that that this is realized by a microcomputer.