CH672852A5 - - Google Patents

Description

DESCRIPTION

The invention relates to a method and a device for room temperature control by means of thermostats according to the preamble of claim 1 and claim 10.

In a known device of this type (DE-OS 3 045 753), a pulse train is transmitted via feed lines which are formed by a ring line and the ground. Each pulse is assigned to a zone; its position in the pulse train is the address code, which is decoded with the help of a counter in each zone. The individual pulses are transferred to the heating resistors in the correct zone and determine their heating power.

Therefore, only a fraction of the total time of a pulse sequence is available for the power supply to a zone. This means that the heating resistors and the control elements have to be designed for relatively large currents, so that the required heating output can be applied to the thermostats in a short time. In any case, the number of zones to be controlled by the main microprocessor is very limited, because with higher zone numbers the time available for each zone is too short to supply sufficient heating power.

It is for better consideration of the wall temperature

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672 852

known (DE-PS 3 310 367) to regulate the heating power in an unsteady heating phase as a function of a constant air temperature setpoint and in the subsequent quasi-stationary control phase as a function of a constant wall temperature setpoint, the actual value of the air temperature and wall temperature being continuous increase.

The invention is based on the object of specifying a method and a device of the type mentioned at the outset in which novel control options result and in which a sufficient heating output can be supplied to the thermostats regardless of the number of zones.

According to the invention, this object is achieved by the features of claims 1 and 10.

Since the daily setpoint, i.e. the setpoint desired by the room user during normal time of day, lies below the intrinsic setpoint of the thermostat, which is based on its design data (e.g. due to the preload of a setpoint spring), the thermostat sensor needs to be heated by the Heating resistor not only during the night setback, but also to achieve the normal daily setpoint. This ensures that the current setpoint can not only be lowered, but also increased. This is done by reducing the electrical power. This results in a number of new control options, as will be explained further below.

The electrical power in daytime operation is preferably dimensioned such that the daily setpoint is 1 ° to 3 ° C, preferably about 2 ° C, below the intrinsic setpoint of the thermostat. This range is then also available for increasing the current setpoint.

It is advantageous if, when the current setpoint changes from a first to a second value, the electrical power is changed in a sliding manner along a ramp function. The sliding change can be made continuously or in small increments. This means that there are no unpleasant temperature jumps for the user. In addition, you get a good flow distribution.

Especially in the warm-up phase of the room, the current setpoint should be gradually increased. The ramp inclination is selected with reference to the inertia properties of the room to be heated and the associated radiator. If the current setpoint is gradually increased in the case of several thermostatic valves, there is no danger that these valves will open completely immediately, thereby disrupting the distribution of the heating water as required. This is particularly important for district heating, where billing is based on cubic meters.

It is preferred to ensure that the current setpoint is raised at a distance before a point in time when the room is expected to be used, and is gradually returned to the daily setpoint at a distance after this point in time. Such a temporary increase in the setpoint preheats the room and provides enough thermal energy so that the cold radiation from the still cold walls, which have cooled down at night, is not unpleasantly noticeable. The gradual lowering of the current setpoint is almost imperceptible to the user.

A special comfort control is obtained when the current setpoint is gradually increased in the evening to a constant, increased setpoint. If the room user no longer does any work in the evening, but only sits quietly and relaxed,

this increase in temperature is perceived as particularly pleasant.

A very important control option is to correct the proportional band error of the thermostat by changing the setpoint depending on the outside temperature. The lower the outside temperature and the greater the flow rate, the greater the control deviation of a proportional valve. This error can be corrected automatically for the first time in this way.

A particularly simple change in the electrical power is obtained by intermittently supplying the heating resistor with current and by changing the pulse-pause ratio of the current in order to change the current setpoint. Comparatively long cycle and pause times can be used because the inertia of the thermostat sensor ensures good averaging.

In some cases it is recommended that the voltage drop across a resistor through which this current flows is measured during the time of the current supply and an error signal is issued if the voltage drop falls below a lower limit value or rises above an upper limit value. In this way, a short circuit or an interruption in the area of the heating resistor can be determined in good time.

In the embodiment according to claim 10, each control device accepts the control command assigned to it on the basis of the address and stores it. Then the control device works autonomously. The associated control element is therefore actuated regardless of which output data the main microprocessor is now outputting for other control devices. At the same time, heating power can be supplied via the control lines to each heating resistor that is switched on via the associated control element. Regardless of the number of zones, the maximum power can be supplied to each heating resistor distributed over 100% of a specified cycle time. The heating current and the load on the heating resistor are correspondingly low.

The digital output data, i.e. address plus control command, can easily be impressed on the feed line voltage or feed line current. These individual bits can follow one another very quickly. For this reason, a large number of control devices can be connected to the common feed lines both in terms of data and in terms of performance. Storage in the sub-microprocessor also allows operation in each zone to be maintained with the most recently valid data in the event the main microprocessor should fail. In the state of the art, on the other hand, the failure of the main microprocessor also leads to a loss of the heating current pulses and thus to a failure of the entire control system.

Overall, this results in a facility with great flexibility, which is particularly well suited for practice.

Since the output data, which can contain other information besides the address and the command, are continuously calculated and output by the main microprocessor, the current setpoint of each thermostat can be changed at any time, both by leaps and bounds and continuously. The main microprocessor primarily takes into account the setpoint program stored for each zone. Since this program is superimposed on the self-setpoint of the thermostat, the user can change the baseline of this program as desired by adjusting this self-setpoint. The additional effort in each zone is relatively small, since the control device and the associated control element can be constructed simply.

The sub-microprocessors can easily convert simple command data into the corresponding switching times or the like.

In the development according to claim II, the control device only needs to control the changeable switch-off time. A simple switching transistor is suitable as the control device.

The two-wire system according to claim 12 requires extremely little wiring and laying effort.

In the embodiment according to claim 13 can

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672 852

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Main microprocessor also pumps, blowers and other work devices can be switched on and off at the correct time, the control being carried out with a similar data structure to that of the thermostats.

The voltage gaps in the device according to claim 14 can be easily generated, for example by a switching element, and easily detected. Since they are in the area of the zeros, they do not affect the electrical power supplied.

The invention is explained in more detail below with reference to preferred exemplary embodiments illustrated in the drawing. Show it:

1 is a schematic block diagram of a device according to the invention,

2 shows the thermostatic attachment of a valve and the associated control device,

3 shows a diagram of the intermittent supply of electrical power,

4 in a time diagram, the change in the current setpoint compared to the daily setpoint TS with rapid heating,

5 shows in a time diagram the change in the current setpoint compared to the daily setpoint TS in the case of comfort heating in the evening,

6 above the outside temperature To the change in the current setpoint compared to the daily setpoint TS to correct the proportional error,

7 is a daily diagram showing a curve for a setpoint program course in which the deviation of the current setpoint from the intrinsic setpoint ES of the thermostat is shown,

8 shows the electrical voltage Ui with impressed voltage gaps and

9 shows a modified embodiment of the device of FIG. 1.

1 shows a main microprocessor 1 arranged in a control center Z, which is provided with a setpoint program memory 2. With the aid of the setting buttons 3, program profiles can be stored for zones I, II and III of a hot water heating system, in particular, therefore, times, sizes and angles of inclination of the changes. Furthermore, an outside temperature sensor 4 is connected to the main microprocessor 1. The inputs 5 are provided for the supply of further values, for example internal temperatures, wind speed, position of the sun and the like. The main microprocessor 1 has a plurality of outputs 6, via which various parts of the system can be controlled, for example circulation pumps, a priority circuit for hot water, rapid heating of the boiler, night lighting and the like.

Output 7 is important for the regulation of interest here. Output data D are sent to a coding device 8 via it. The output data include at least one address for the individual zones I, II and III and a command that identifies the size of an electrical power. As a rule, however, the output data also include further information, for example synchronization signals, temperature information and the like. It is digital output data which is imprinted in the coding device 8 with a current I which is in the two cables 9 and 10 of a two-wire system -stems 11 flows. A full-wave rectifier 12 is connected to the source of an alternating voltage U, so that a rectified alternating current flows according to FIG. 8 in the two-conductor system 11. The coding device 8 has a switching element that either does not influence the zeros of the voltage half-waves at all or (b) provides a wide current gap: or (c) provides a narrow voltage gap. The wide voltage gap can correspond, for example, to the value 1 and the narrow voltage gap to the value 0.

The hot water heating system has several thermostatic valves 13, which are arranged in several zones I, II and III of a house to be heated. There is usually more than the number of zones illustrated, for example eight zones. In the exemplary embodiment, each zone corresponds to a room and therefore contains only one thermostatic valve. However, several rooms in which the current setpoint is to be influenced in the same way can also be combined to form a zone with several thermostatic valves. The thermostatic valve 13 has a housing 14 and a thermostatic attachment 15. The working element located inside this attachment is connected via a capillary tube 16 to a temperature sensor 17 which is located in a housing 18. If the sensor 17 has a rapid \ liquid-vapor filling, the temperature-dependent vapor pressure acts in the working element of the attachment and the valve assumes an equilibrium position because a setpoint spring acts in the opposite direction to the working element. The attachment has a rotary handle 19, with the aid of which the intrinsic setpoint ES of the thermostatic valve can be changed, for example the setpoint spring can be adjusted. If the sensor 17 has a liquid filling, the position of the working element in the attachment can be changed using the rotary handle 19.

An electrical heating resistor 20 is present at the sensor 17, which can be supplied via the two-wire system 11 with a current dependent on the half-wave voltage Ui of FIG. 8 if a control element in the form of a switching element 21, for example a switching transistor , has been controlled in the conductive state. The control is carried out by a control device in the form of a sub-microprocessor 22, to which a decoding device 23, which can also form part of this microprocessor 22, is assigned. The decoding device 23 scans the zeros of the half-wave voltage Ui, determines the bits therefrom and stores those values which are associated with the address of the associated zone. On the basis of information received for this section, the switching element 21 is brought into the conductive state. The switch-off time is controlled in a time-dependent manner on the basis of the stored command data, as is shown in FIG. 3. The individual blocks each correspond to a large number of half-waves. The switch-on time is determined by the cycle time of fifteen seconds. It can be seen that the duty cycle decreases in the order of blocks d, e, f and g, so that the heating of the sensor 17 by the heating resistor 20 can be changed in this way.

The housing 18 accommodates the parts 17, 20, 21, 22 and 23 mentioned.

The self-setpoint ES of the thermostatic valve, which would be set if the heating resistor is not active, has a higher value than a user would like during the normal course of the day. The diagram in FIG. 7 illustrates that the self-setpoint is, for example, 23 ° C., while the daily setpoint is only 21 ° C. This reduction by 2 ° C is achieved with the help of the heating resistor 20. The daily setpoint TS is therefore composed of two components, the self-setpoint SE and the electrical power supplied to the heating resistor 20. If you change the electrical power, the reduction in relation to the self-setpoint changes. If you change your own setpoint, the entire setpoint program shifts.

Because it is necessary to supply a heating output to achieve the daily setpoint, the current setpoint can not only be reduced but also increased compared to the daily setpoint. For example, if a heating output corresponding to block e in FIG. 3 is required to achieve the daily setpoint, the current setpoint can be raised by reducing the heating output in accordance with blocks f and g.

A rule character working with such an increase5

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ristic results from Fig. 4. There it is shown - starting from the daily setpoint TS - that the current setpoint is raised by 1.5 ° C and later gradually returned to the daily setpoint using a ramp function. The setpoint is increased half an hour before the expected start of use (hour 0) and remains unchanged another hour after the start of use. The setpoint is then returned linearly for another hour. Incoming users find the room pleasantly warm. The cold potential of the walls cooled during the night is reduced as quickly as possible. The gradual return of the temperature is practically unnoticed by the user.

3 A comfort control is shown in a time diagram in FIG. In the evening, the current setpoint is gradually raised over three hours, i.e. here between 7 p.m. and 10 p.m., by 1.5 ° C above the daily setpoint TS. This increased setpoint then remains unchanged, for example until midnight. The increase takes account of the fact that a person sitting calmly feels a slightly higher temperature than a moving, working person. This increase in temperature is reversed when the user withdraws to sleep.

In Fig. 6 it is shown above the outside temperature To that the temperature can be varied by 1 ° C. The correction is 0 below an outside temperature of - 9 ° C. The correction is 1 ° C above + 9 ° C. The correction temperature rises steadily between these two outside temperatures. In this way the P-band error of the thermostatic valves is compensated.

7 shows a curve P with the course of the program from 0 to midnight. The daily setpoint is 2 ° C below the thermostat's own setpoint. A basic reduction of 1.5 ° C and a P-band error correction of 0.5 ° C are taken into account. During the night, between midnight and 4 a.m., the night temperature drops by 9 ° C compared to the target value, for example to 15 ° C. This is achieved by heating the sensor 17 strongly. At 4 a.m., the temperature increases to the daily setpoint and at 6:30 a.m. a further increase by 1.5 ° C because the first users of the room are expected at 7 a.m. Section h of curve P therefore corresponds to FIG. 4. The normal daily target value TS is set from 9 a.m. to 7 p.m. Then there is a gradual increase of 1.5 ° C to increase the feeling of comfort. Part g of curve P therefore corresponds to FIG. 5. There is therefore a cold phase AI, a warming-up phase A2, a warm phase A3 and a cooling phase A4. The length of the warm-up phase A2 depends on how much the room in question had previously been cooled and what heat storage properties the room or the heating system has.

7, a curve branch PI is shown in dash-dotted lines, in which, in the warming-up phase A2, the setpoint increases continuously along a ramp function.

All ramp functions are drawn as straight lines. But they can also be composed of small steps.

672 852

The entire system is expediently operated with a mains frequency and a reduced voltage of, for example, 24V. In one embodiment, the main microprocessor 1 operated to transmit new output data to the individual sub-microprocessors 22 every three seconds. This data is saved and deleted when new data appears; however, only the data that was last transmitted before the end of the 15-second cycle is used.

The main microprocessor can also detect the line voltage and change the length of the current blocks (FIG. 3) depending on possible line voltage fluctuations. For example, the mean value of the voltage U is measured and fed to the main microprocessor 1 via an input 5.

1 schematically illustrates how a monitoring device 24 measures the voltage drop across a resistor 25 in series with the heating resistor 20 during the current charging and, when the measured value deviates from a predetermined range, emits an error signal for actuating a light signal transmitter 26. The user of the room can therefore recognize the fault if the heating resistor should be short-circuited or there is a power cut.

9 shows that on the two-pipe system 11 not only the control devices 22 for the thermostatic valves 15 of radiators 27, but also additional control devices 28 to 34 for further work units, each of which has an on-off function, are connected. These additional control devices only have the following task, for example: Additional control device 28 switches on a frost protection device. Additional control device 29 switches on the fuel and / or air supply for a boiler 35. The additional control device 30 switches on a circulation pump 36 for heating a domestic water heater 37. The additional control devices 31, via a control unit 38, actuate the mixing valve 39 in such a way that the boiler temperature increases rapidly. The additional control device 32 switches on a circulation pump 40 in advance. The additional control device 33 can be used to switch on the lighting. The additional control device 34 serves to switch on a fuse. The additional control devices are also each controlled by an address in the output data D and switched by a command likewise contained in the output data. In a specific heating system, only the additional control device required for this need be provided in each case. The main microprocessor 1 in the control center Z has the option of controlling all additional control devices in addition to the control devices 22 for the thermostatic valves 15; however, these options do not have to be fully exploited.

It does not have to be recognizable from the outside that the thermostat is set to a higher self-setpoint than the daily setpoint. All you need is the setting scale on the thermostat to adjust the 2 ° C drop caused by the heating.

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Claims (15)

672 852 1. Method for room temperature control, in which heat is supplied to the room under the influence of a thermostat and the current setpoint from a daily setpoint set for the stay of a person by supplying electrical power to a heating resistor assigned to the thermostat sensor to a heating resistor that is assigned to the Setpoint of the thermostat reduced setpoint can be reduced, characterized in that the intrinsic setpoint of the thermostat is a predetermined amount above the daily setpoint and the heating resistor is supplied with electrical power even during the day, so that the daily setpoint is based on the setting on the thermostat and the heating of the thermostat sensor, and that the electrical power supplied is reduced in order to achieve a control characteristic with an increased setpoint. 2. The method according to claim 1, characterized in that the electrical power in day operation is dimensioned such that the daily setpoint is 1 to 3 ° C, preferably about 2 ° C, below the intrinsic setpoint of the thermostat. 2nd PATENT CLAIMS 3. The method according to claim 1 or 2, characterized in that when the current setpoint is changed from a first to a second value, the electrical power is slidably changed along a ramp function. 4. The method according to any one of claims 1 to 3, characterized in that in the warming-up phase of the room, the current setpoint is raised gradually. 5. The method according to any one of claims 1 to 4, characterized in that the current setpoint is raised at a distance before a point in time at which the use of the room is to be expected and is gradually returned to the daily setpoint at a distance after this point in time . 6. The method according to any one of claims 1 to 5, characterized in that the current setpoint is gradually increased in the evening to a constant, increased setpoint. 7. The method according to any one of claims 1 to 6, characterized in that to correct the proportional band error of the thermostat, the setpoint is changed depending on the outside temperature. 8. The method according to any one of claims 1 to 7, characterized in that the heating resistor is intermittently supplied with current and the pulse-pause ratio of the current is changed to change the current setpoint. 9. The method according to any one of claims 1 to 8, characterized in that during the time the current is fed, the voltage drop across a resistor through which this current flows is measured and an error signal is emitted if the voltage drop falls below a lower limit or above an upper limit Limit increases. 10.Device for performing the method according to claim 1, for room temperature control by means of thermostatic valves of a hot water heating system, the sensors of which are each assigned a heating resistor and which have an adjustable intrinsic setpoint, with the supply of electrical power to the heating resistors-controlling elements, in one A main microprocessor provided with a setpoint program memory is arranged, which, depending on at least the setpoint program, issues control commands that characterize the electrical power to be supplied to the thermostats, zones with differently adjustable setpoint temperatures being provided with one thermostat or several thermostats to be influenced in the same way, and each Zone is assigned a control device for actuating the control element, and the supply lines common to all the heating resistors and supplying the electrical power also the main microprocessor with the control devices Connect n to transmit the control commands, characterized in that that the output (7) of the main microprocessor (1) is provided with a coding device (8) which contains a sequence of digital output data (D), each comprising the address of a zone and a control command, of the feed line voltage (U) or the supply line current (I), and that the control devices (22) are formed by sub-microprocessors with decoding device (23), each of which stores a control command corresponding to its own address and actuates at least one control element (21) as a function thereof . 11. The device according to claim 10, characterized in that the control element (21) is a switching element which can be switched into the conductive state by the control device (22) intermittently at a predetermined switching frequency but with a variable duty cycle. 12. Device according to claim 10 or 11, characterized in that the feed lines (9, 10) form a two-wire system. 13. The device according to claim 12, characterized in that additional control devices (28 to 34) for work units, each having an on-off function, via the two-wire system (11) with the main microprocessor (1) connected and can also be actuated by its output data having an address and a command. 14. Device according to one of claims 10 to 13, characterized in that the feed lines (9, 10) are connected via a full-wave rectifier (12) to an AC voltage source (U), that the coding device (8) the output data (D) of the main microprocessor (1) impresses bit by bit of the rectified AC voltage in the region of its zeros as voltage gaps (b, c) with two different widths and that the decoding device (23) detects the voltage gaps and their width and derives the respective bit from this. 15. Device according to one of claims 10 to 14, characterized by a measuring resistor (25) lying in series with the heating resistor (20) and by a monitoring device (24) which measures the voltage drop across the measuring resistor and emits an error signal when the voltage drop falls below one lower limit falls or rises above an upper limit.