CH637753A5 - CIRCUIT ARRANGEMENT FOR DETERMINING THE OPTIMAL SWITCH-ON TIME OF A HEATING OR AIR CONDITIONING. - Google Patents

Description

20 The invention relates to a circuit arrangement for determining the optimum switch-on time of a heating or air-conditioning system after a switch-off period according to the preamble of claim 1.

In such a device, known from DE-OS 2 630 920, for controlling and / or regulating a heating or air conditioning system, a minimum room temperature, the so-called support temperature, is maintained between two occupancy periods of the rooms to be heated or air-conditioned. This support temperature is raised below a certain outside temperature as a function of the outside temperature, so that a constant switch-on time can be selected before the occupancy period for heating up the rooms with the maximum available heating output below the certain outside temperature. Only at an outside temperature above the certain value is a later switch-on time calculated in order to reach the desired room temperature at the beginning of the occupancy period.

A major disadvantage of this known circuit arrangement is the difficulty in optimally adapting it to the given shadows of the heating or air conditioning system.

Another circuit arrangement of this type is known from US Pat. No. 3,964,676.

The principle of such circuit arrangements serves to achieve an optimal efficiency of a heating or air-conditioning system in a building used only at certain times, such as in a business or school building. Efficiency is optimal if, on the one hand, a comfortable room temperature is only maintained during the occupancy periods and, on the other hand, as much heating energy as possible is saved during the 50 non-occupancy periods. The savings are greatest when the room temperature drops to a permissible minimum during the non-occupancy periods and the latest possible time is selected for the start of heating in order to heat up the rooms in the shortest possible time with the greatest heating output available. The switch-on time is optimal when the room temperature required for comfort is reached at the beginning of the occupancy period and not beforehand.

However, the optimum switch-on time is not a constant 60 value, but depends on the cooling of the rooms to be heated and on the heating-up time, which is expressed in the following by the heating slope. The heating slope is given in K / h (° K / hour) and depends on the construction (insulation, etc.) of the building to be heated, on the prevailing outside temperature and on the temperature of the heating or air conditioning system.

The design temperature corresponds to the lowest outside temperature for which the heating or air conditioning system is designed,

3rd

637 753

i.e. is calculated and at which the heating or air conditioning system operated with the full available heating capacity is just able to heat up the rooms. The heating slope is lowest at the lowest outside temperature because the constant heat losses of the building are then greatest. The heating by an equal amount therefore takes longer at the lowest outside temperature than at a higher outside temperature at which the heating slope is greater.

Since the heating slope is not a constant value, as has been shown in the description above, it is necessary to adapt the heating slope to the heating or air conditioning system in order to achieve an optimal switch-on time, taking into account the design temperature and the construction of the building.

It is known to enter the design temperature specified for a system in a programmed control device in order to determine the optimum switch-on time. However, there is no guarantee that the switch-on time can actually be optimally determined by the control unit, because it is known that many heating systems are oversized when calculating them due to safety surcharges. The actual design temperature is therefore lower than the value on which the calculation is based. In such a case, the result of entering the calculated values into the control device is a greater heating slope than is desired, and thus a premature reaching of the room temperature required for the comfort. The possibility of saving heating energy is not optimally used in such a case. Another disadvantage of the type of input mentioned is that the heating slope can only be set by one point, namely to the design temperature, which is very rarely reached anyway. Such a setting does not allow, for example, that the values of the heating gradients dependent on the outside temperature, which are defined by a straight characteristic curve, can be set as desired for optimal adaptation. For example, swiveling and independent parallel displacement of the straight characteristic curve is not possible.

Since the interior in the rooms to be heated cools down more than during a night, for example over a weekend, especially at low outside temperatures, it is sufficient to take into account the falling room temperature, which is particularly defined by the air temperature , Not. Although the room temperature reached the selected value at the beginning of the occupancy period, the desired level of comfort is not available in such a case because the furnishings, and in particular the walls of the rooms, have cooled more than during just one night. In order to guarantee the comfort at the beginning of the occupancy period, it is known, for example, to advance the switch-on time by a certain amount on Monday morning. However, since the switch-off periods lasting longer than 24 hours can last from one day (individual public holiday within the week) to several days (Christmas and New Year), this results in cooling of the walls and furnishings to different degrees. These differences are not taken into account in the methods and devices that belong to the prior art.

The invention is therefore based on the object of specifying a circuit arrangement for determining the optimum switch-on time, which enables complete adaptation to the given properties of the system without complicated calculations. Furthermore, cooling of different degrees due to different periods of switch-off periods should also be taken into account.

The object can be achieved according to the invention by the features specified in the characterizing part of claim 1.

The circuit arrangement according to the invention enables a clear and easy-to-understand setting of the slopes required for any outside temperature. The two setting elements for setting the characteristic curve which can be set are preferably assigned to two spaced-apart outside temperature values, one above 10 ° C. and one below 0 ° C. The uncomplicated setting also enables less trained personnel to optimally adapt the circuit arrangement to the given properties of the system to be controlled.

In claim 4, a solution is shown, which enables an opti-i5 male adaptation even with different lengths of switch-off periods.

As a particularly advantageous embodiment of the invention, the function of the computer circuit is defined in claim 10.

An exemplary embodiment of the subject matter of the invention is explained in more detail with the aid of the drawings.

Show it:

1 is a block diagram of the circuit arrangement,

2 is a nomogram for determining the heating part 25 units,

Fig. 3 is a functional diagram of the circuit arrangement according to Figures 1 and

Fig. 4 shows a further functional diagram to explain the additional early heating.

30th

The circuit arrangement according to FIG. 1 has a computer 10, to which signal voltages Ux and U3 as well as a signal voltage U2 and a reference voltage Uref are fed via an adder 12. The output signal voltage of the computer 10 is designated U4. Two setting elements in the form of potentiometers 14 and 16 are arranged parallel to one another between the adder 12 and the computer 10. The potentiometer 14 is used to set the heating slope S + and the potentiometer 40 meter 16 is used to adjust the heating slope S—. The voltage U3 supplied to the adder 12 can be set on an adjusting element in the form of a potentiometer 18. The voltage Uj supplied to the adder 12 corresponds to the temperature difference between a setpoint xk and the 45 room temperature ta. The voltage U2 corresponds to the measured outside temperature ta.

A temperature-dependent resistor 20, which is connected 50 in series with a resistor 22 between the reference voltage Uref and ground, is used to measure the outside temperature ta. The center tap between these two resistors 20 and 22 is connected to the input of an amplifier 24, the output signal of which is the voltage U2 supplied to the computer 10.

A temperature-dependent resistor 26, which is arranged in series with a resistor 28 between the reference voltage Uref and ground, is used to measure the room temperature. To set the desired value xk of the selected room temperature tr, a potentiometer 30 is provided, which is arranged in series with a resistor 32 between the reference voltage Uref 60 and ground.

The connection points between the temperature-dependent resistor 26 and the resistor 28 and between the potentiometer 30 and the resistor 32 are connected to the two 6S inputs of a differential amplifier 34, the output signal of which is the voltage Uj supplied to the adder 12. This voltage corresponds to the temperature difference A tr between the setpoint xk and the room temperature tr.

637 753 4

The output signal voltage U4 of the computer 10 is pulled across these two points and is fed to the first input of a first comparator 36 on both sides. Extend that. At the ordinate scales S— and S + are then the second input of the first comparator 36, a span- the corresponding setting values can be read off. In the illustrated voltage U5, which, depending on the time, the exemplary embodiment according to FIG

proportionally increasing voltage. The output of the com- 5 with the setting value S - via two and with the setting value S + via parators 36 is in each case with the setting input S of a first and six K / h.

a second flip-flop circuit 38, 40. The straight line 60, which is extended downward, ends at an output Q of the first flip-flop circuit 38 and has an excitation temperature value of minus 40 Celsius. This is linked to the theory of relay A. see value in which a heating of the to be heated or to

The first input of a second comparator 42 has the air-conditioning rooms available even in the largest one

Reference voltage Uref supplied. The second input of this standing heating power is no longer possible. With such a

The time-dependent voltage U5 is fed to comparator 42;

The output of the comparator 42 is at most still held with the reset input temperature at the greatest heating power

R of the first flip-flop circuit 38 is connected. will.

15 In the nomogram according to Figure 2 is above the abscissa

The reset input R of the second flip-flop circuit 40 is plotted on a second scale, which is compared to the outside

connected to the output of a first counter 44. temperature scale Ta is shifted to the left by 5 degrees Celsius.

The outputs of a changeover contact 46 are not related to this. The scale designated tAusIege is related to the switching temperature already mentioned in the time switch shown with the setting input S and with the introduction to the description.

the reset input R of a third flip-flop circuit 48 ends in the embodiment shown in FIG. In order to start the circuit arrangement for determining the straight line 60 at a design temperature of minus 35 degrees, the instant at which the switch-on occurs, the switchover Celsius shows. So this is the lowest outside temperature value, at clock 46 to the set input S of the third flip-flop circuit 48. Which the system just connected the rooms

In the position shown, the changeover contact 46 is capable of heating up.

Reset input R of the third flip-flop circuit 48 is connected, since the determination of two measured values for determining which position of the switch-off period of the heater 60 to be controlled presupposes that it corresponds to two different air conditioning or air conditioning systems. Outside temperature values ta are recorded, it is also possible for the first counter 44, a second counter 50 and a third, for the provisional determination the straight line 60 two counters 52 are each via their first input with the appearance of one measuring point and one to the System specified gear connected to an oscillator circuit 54. The output Q is designed to pull out the temperature. Such a determination of the third flip-flop circuit 48 with the second input corresponds to the optimum only if the specified second counter 50 is connected. The inverted output Q is the correct temperature. However, the specified counter 52 should not be connected to the second input of the first counter 44 and the level design temperature. The output of the second counter 50 is more accurate with the input than a set value, which is only connected to the design of a first distal-analog converter 56, the temperature of which is based, for example, as is the case with the input for the state of the output voltage which is proportionally common depending on the technology of the devices.

Time rising voltage is U5. The following is the function of the circuit arrangement

The output of the third counter 52 is connected to the input according to FIG. 1 with the aid of the diagram according to FIG. 3 closer to a second digital-to-analog converter 58, the latter of which will be explained. To avoid confusion, be

Output voltage is voltage U3. noted that the straight line shown in Figure 2

On the basis of the nomogram shown in FIG. 2, 60 should not represent the heating slope, but rather its coefficient

Now the determination of the setting values S - and S + will be explained on this straight line 60. In the diagram according to which values on the potentiometers 14 and 16 (FIG. 1) of FIG. 3, on the other hand, the heating slopes S—, S + and are to be set. On the abscissa axis of this nomogram there is an optionally assumed heating slope S lying between the values S - and a scale with the values of the outside temperature in degrees S +.

Celsius applied. For the outside temperature values of plus The abscissa labeled t corresponds to the time axis, 20 degrees Celsius and minus 20 degrees Celsius each is one that can be divided into hours or days, for example. Ordinate axis. The scales on this ordinate- The ordinate corresponds to the room temperature tr in degrees Celsius, axes are related to a heating slope, which is given here in The value xk on the room temperature axis is that at the setpoints / hour (K / h). The ordinate axis with a setpoint of the room temperature set in FIG. 30 (FIG. 1). Outside temperature ta of minus 20 degrees Celsius is denoted by S -, 62 denotes the end of the occupancy period, while the ordinate axis ends with the outside temperature - which ends at switch-off time 64. Between the off. ratur ta of plus 20 degrees Celsius is labeled S +. These switching times 64 and the beginning 66 of a subsequent assignment values S— and S + denote the assignment period 68 which is connected to the potentiometers 14 and a non-assignment period 70.

and 16 values to be set in FIG. 1 of the heating part. After the switch-off time 64, the room temperature begins.

Ness. The outside temperature values of minus 20 degrees Celsius drop after an e-function according to curve 72,

and plus 20 degrees Celsius are arbitrarily selected values and A tr denotes the difference by which the room temperature

apparatus-related. temperature 72 up to a switch-on time 74 compared to

In order to determine the values S - and S +, the heating setpoint xk has dropped.

or the air conditioning system is switched on after a switch-off period. The switch-on time 74 is given by the cross

and measured the increase in room temperature per hour. point between the falling room temperature 72 and

The measured value is based on the prevailing outside temperature or the prevailing outside temperature.

Outside temperature in the nomogram according to FIG. 2 heating slope S. Provided that they wear. In order to achieve an optimal adaptation, it is advantageous.

If the outside temperature is different, the same room temperature 72 'at exactly the time 66, at which

drive to repeat. If two such measurement points are present, the following occupancy period 68 begins, the setpoint is entered and entered in the nomogram, a straight line 60 xk can be used.

5 637 753

The heating slopes S -, S and S + are in the diagram. The second relay B. remains energized, namely as long as

according to FIG. 3 simplified represented by straight lines. until the second flip-flop circuit 40 has its reset. The increasing room temperature IT will receive a signal from the first counter 44 in relation to a gear R. The second re-such straight line behaved slightly S-shaped. Such a relay B is intended to control the normal control system of the heating

Deviation is irrelevant, however, since it is only a matter of keeping the air conditioning switched on during the day, so that the rising room temperature 72 'occurs as far as possible. or air conditioning by an amount equal to the time

The circuit arrangement according to FIG. 1 now corresponds to this. This delay is used to compensate for determining the optimum switch-on time 74. For the purpose, since the time switch contact 46 also achieves this goal by such an amount, it is necessary for the determination to switch back to its night position before the occupancy ends. That begins at a point in time, which is in a sufficient first counter 44, via the inverted output Q, the third distance before the start of occupancy 66, so that a flip-flop circuit 48 is activated.

tion at the most reduced room temperature and FIG. 4 shows a diagram which extends over a period of several days which is still possible at the lowest expected outside temperature. The function shown in this slide in order to achieve the selected room temperature 15 grams at the start of occupancy 66 differs from that. For this purpose, the time switch contact 46 according to FIG. 3 is made in particular by the fact that the switch-off at the time 76 to the set input S of the third flip-flop period lasts longer than 24 hours. Since, as already mentioned, the circuit 48 is switched over and thus the determination of the opti-furnishings and the walls are initiated at a time when the switch is on. Via the output Q to cool the unheated space more than 24 hours of the third flip-flop circuit 48, the second counter 50, which is only activated during one night, is expedient for the user to receive time-dependent pulses from the oscillator 54. Switching point 74 'in addition to the normal determination of the opti-In the first digital-to-analog converter 56, the time from the second switch-on point is brought forward. In the exemplary embodiment shown, these time pulses delivered in the time-dependent increase are supplied by converting the voltage U5. when determining the optimal switch-on time a

25 room temperature is used as a basis, which is lower than the tat-die from the switching elements 10, 12, 14, 16 and 18, the existing room temperature.

The computer circuit provides the signal voltage U4, in which the outside temperature ta, the difference in room temperature. Because the cooling mentioned above, depending on the A-A tr, the setting values S - and S + and, if applicable, the number of days not used, continues to increase, it is provided Signal voltage U3 to be explained in greater detail as a function of 30 within a non-occupancy period of the determination of the position of the potentiometer 18 are evaluated. The optimal switch-on time-based value for the function of this computer circuit is to be reduced further in each case in claim 10 by one step. In the diagram, a mathematical formula is shown. FIG. 4 shows these reductions at times 80 and 82 is now at the first input of first comparator 36. Time 80 is at voltage U4 with respect to switch-off time 64 '. As soon as the time-dependent rising voltage35 shifted by 24 hours. The second point in time 82 is against U5 at the second input of the first comparator 36 and has reached the value above the first point in time 80 by a further 24 hours, the first comparator 36 inputs a value. The broken line 84 indicates the output signal on which the design is based at the set inputs S of the first and the two values to be assigned. Instead of the room temperature difference th flip-flop circuit 38.40. After a switch-off period of more than two days, the two relays A and B are energized via these two flip-flops - A t3, and over 40, for example over a weekend, the value A tr 'of the determ. or based on the optimal switch-on time 74 ', the system for heating the connected rooms during the switch-on Without this advance, the switch-on time would be switched on to the greatest available heating output. Intersection point 75 between the respective value of the ab-This switch-on takes place exactly at the switch-on point 74. Falling room temperature 72 and the slope straight line S

The 45 defined by switching the time switch contact 46 fall. It can be seen from the diagram that the time period 76 for initiating the start of the determination is, compared to the additional advance, from the respective heating section over the beginning 66 of the occupancy period 68 by one time and is therefore dependent on the outside temperature. If the amount is low, for example by 9 hours, brought forward. To the outside temperature, corresponding to the slope S - simplification of the setting by the operating personnel results in a greater additional advance than with the slope, the switching contact 46 actuating, but not close 50 S +, which is assigned to a higher outside temperature. The time switch shown here can be set up so that it automatically switches to 9 hours before the setting time. In the slide-up rate, there is an advantage by which the optimal program according to FIG. 3 denotes the time period of the advance with the mood of the switch-on time 74 'in each situation. is guarantied.

The electronic circuit, which has the switching elements 50 and 56, is implemented by the local timer so that its output voltage, supplementary signal voltage U3, which is set on the potentiometer 18-U5 exactly after the period 78, the reference voltage to the portion of the room temperature dependent uref reached. The voltage Ux is added by equality of the two input voltages. The scale of the potentiometer 18 Uref and U5 on the second comparator 42 receives the first flip-flop can be calibrated in ° K.

Circuit 38 sends a signal via its reset input R, whereby 60 the third counter, output Q is used to generate voltage U3 and the first relay A is disconnected and the second digital-to-analog converter 58. These two fall. The latter function takes place at time 66, in the case of circuit elements 52 and 58 are set up in such a way that the rapid heating is ended. Output voltage U3 is increased by a further step every 24 hours. The third counter 52 is activated via 65 the inverted output Q of the third flip-flop circuit 48.

C.

1 sheet of drawings

Claims (5)

637 753 PATENT CLAIMS 1. Circuit arrangement for determining the optimal switch-on time (74) of a heating or air-conditioning system after a switch-off period in order to obtain the desired room temperature (xk) at the beginning of the following occupancy period (68), at a predetermined time period (78) before the beginning of the occupancy period (68), a room temperature-dependent and an outside temperature-dependent signal (Uj, U2) are evaluated with a computer circuit (10, 12), on the input of which the external temperature (ta) dependent signal (U2) is connected and the output of which is connected to the input of a comparator (36), and to a timer (46,48,54,50,56) acting on the comparator (36), characterized in that means (34) to form a signal (U x) corresponding to the difference between the desired value (xk) of the desired room temperature and the measured room temperature (tr) are connected to the computer circuit (10, 12) and that the Rec Circuit (10, 12) is assigned two setting elements 14, 16) for setting a characteristic curve (60), by means of which the heating gradients (S-, S +) can be determined at two different outside temperature values (ta). 2. Circuit arrangement according to claim 1, characterized in that the computer circuit has an addition element (12) and a computer (10) and that the setting elements (14, 16) for setting the characteristic curve (60) between the addition element (12) and the computer (10) are switched. 3. Circuit arrangement according to claim 2, characterized in that the means for forming the differential signal (Ut) contain a differential amplifier (34), the output of which is connected to the one input of the adder (12). 4. Circuit arrangement according to claim 3, characterized in that the other input of the adder (12) is connected to means (46, 48, 52, 54, 58) by means of which the adder (12) can be supplied with a supplementary signal (U3), which is generated after at least one non-occupancy period (70) lasting longer than 24 hours in order to advance the switch-on time (74 ') by simulating a greater drop in room temperature (Atr) than is actually present. 5. Circuit arrangement according to one of the preceding claims, characterized in that the timer has a time-dependent switch (46), the switching point is advanced by a specified time span (78) compared to its time setting value. 6. Circuit arrangement according to claim 5, characterized in that the switch (46) is followed by a time control device (48, 54, 50, 56) in order to supply the comparator (36) with a time-dependent signal (U5). 7. Circuit arrangement according to claim 6, characterized in that the time control device has electronic switching elements (54, 50, 56) in order to emit a voltage which is linearly variable as a function of time as a time-dependent signal (U5). 8. Circuit arrangement according to one of the preceding claims, characterized in that one (14) of the two setting elements (14, 16) has an outside temperature value (S +) above 0 ° C and the other (16) has an outside temperature value (S -) below 0 ° C is assigned. 9. Circuit arrangement according to one of the preceding claims, characterized in that the two setting elements (14, 16) are matched to the computer circuit (10, 12) in such a way that the slope values (S) can be changed linearly as a function of the outside temperature values (ta). 10. Circuit arrangement according to claim 4, characterized in that the computer circuit is based on a function according to the following formula: U4 = (U1 + U3ak) U22 (os_-as +) + cts. urefz 5 where: Ux signal voltage of the room temperature difference (xk - tr) U2 signal voltage of the outside temperature (ta) U3 signal voltage of the supplementary signal U4 output signal voltage of the computer circuit 10 Ure £ reference voltage ak Setting element for the heating slope at an upper setting point