DE4028501C2 - Procedure for controlling the heating of rooms - Google Patents

Description

The invention relates to a method for controlling the heating of rooms of a building according to the generic term of the independent Claim, wherein the room temperature is temporarily low Level is lowered and the heating to a higher target space temperature should start at the latest possible time.

From DE-OS 29 39 719 and 34 42 441 and "climatic-cold Hei tongue ", No. 11 / '81, page 491-494, methods are known at which a temperature sensor in one of the rooms to be heated in Connection with a weather-compensated VT controller with an Algo used for the self-optimizing heating time calculation becomes. The room temperature sensor can be used to check whether and what deviations between the actual room temperature and the programmed one Time of the target room temperature exist.

The disadvantage here is that these methods in buildings where no representative test room for the room temperature check exists, cannot be used.

The invention has for its object a method of the above Specify the type mentioned, the exact determination of the heating allowed without an actual room temperature measurement is required. According to the invention to solve the problem  characterizing features of the independent patent vorese hen.

According to this basic teaching, the optimal duration of the Determine the heating-up time using the following formula:

Equation (1)

The following applies to K₁:

Equation (2)

and approximately

Z _{G is} the lowering time, which also includes the heating-up time Z _A , which results from the program to be specified by the user (start and end of heating with a reduced temperature level),
K₁ a size proportional to the building constant K _Geb ,
t _A the current outside temperature,
t _{amine is} a maximum outside temperature that is relevant for the design of the heating system,
t _iN the desired target room temperature,
Δt _{A is} the difference between the target room temperature t _iN and the minimum outside temperature t _Amin and
A, B, C and n constants.

With the default value for Z _A from context (1), the controlled heating begins before the programmed point in time of reaching the increased set room temperature.

Advantageous further developments result from the subclaims, aimed at increasing the level of accuracy of the procedure are.

The invention is explained below with reference to the drawings.

In detail show the

Fig. 1 to 4 by means of diagrams the functional relationship between the already mentioned above, is decisive for the determination of an opti paint duration of heat-up characteristics.

Fig. 5 illustrates the scheme represents an apparatus suitable for carrying out the method the heating system.

First, the diagram of FIG. 1 shows the functional relationship between the actual height of the outside temperature, the minimum outside temperature t _amine , three different building constants K 1, K 2, K 3 and the ordinate of the heating-up time Z _A for the duration of the lowering operation Z _G. The heating-up time Z _{A is} the period within which the actual room temperature rises from the start of the room heating to the desired value of the room temperature. This duration is given as a percentage of the total lowering time. At the minimum outside temperature t _Amin , the maximum output required for room heating is achieved at the set room temperature t _iN . For example, t _amine was assumed to be -15 ° C, the target room temperature t _iN is, for example, + 20 ° C. Δt _A is therefore 35 K. The building constant K _Geb proportional size K₁ is different and takes into account the individual inertia of the building in terms of heat absorption and storage capacity. K₁1 is assumed to be greater than K₁2 and K₁2 is greater than K₁3.

From this Fig. 1, the effect of three different building constants K₁ on the heating time Z _A required in each case can be seen.

A power excess factor f _H at a temperature of t _amine is 1.0 in this case, that is, there is no excess, the heating power required is just still covered by the heat generator. The course of the curves shown in FIG. 1 results from iteration from the known relationships

and

Therein τ means the so-called heating time constant, f _H the ratio of the output of the heat generator to the heating output, which is required at t _amine to enable a room temperature of t _iN , t _iO the room temperature after the time Z _E at the beginning of the heating from the lowering to the increased room temperature level.

FIG. 2 also shows in such a diagram the functional dependence of the heating-up time Z _A on the outside temperature t _A , namely in accordance with outside temperatures of t _amine of -10 ° C., -15 ° C. and -20 ° C. in curves 1 , 2 or 3 .

In any such minimum outdoor temperature t _amine, it is assumed that from the heater, the maximum power is output, that is f = _H. 1

The calculation of the curves in a ver in heating controllers used microcomputer requires a relatively high computing time and a considerable space requirement.

The existing requirements are closed solving linear equation much better. For this will According to the invention, an approximation is used as follows:

where Z _{A is} the desired time period in hours, K₁ one of the building's time-constant proportional dimensionless quantity, Z _G the time period of the deviation from the increased room temperature target value t _iN in hours,
t _{A is} the actual outside temperature in ° C, t _{amine is} the minimum design temperature of the heating system in ° C, Δt _{A is} the difference between the set room temperature t _iN and the minimum outside temperature t _amine in ° C.

This approximate course is shown in FIG. 2 as curve 4 .

The following relationship can be used to adapt the factor K 1 to the physical building time constant K _Geb :

A, B, C and n mean mathematical constants for the error nominal approximation.

This adaptation can advantageously be carried out by the computer of the control unit be performed.

In practical systems it can happen that the power excess factor f _H <1 at the set minimum outside temperature. The result is that the heating-up time is calculated too long, although the time constant is set appropriately. Since no room sensor can be used for correction, a size that is approximately proportional to the actual heat requirement must be used. It can be entered manually. But an automatic adjustment to the circumstances of the Heizsy stems is advantageous.

For example, if a period of time is measured from switching on the heater until it is switched off for the first time, which is shorter than the calculated heating-up time, there must be an excess of power, i.e. f _H is greater than 1. This means that the actual minimum outside temperature t _amine , at which the target room temperature t _{iN can} still be maintained, is lower. The point of curve 2 , in which the heating time is 100% at t _amine , could be shifted to the left up to curve 3 , which increases the difference Δt _A to Δt _A.

This is done by determining a correction factor from the ratio of the calculated heating time to the measured switch-on time. With this correction factor, a new difference .DELTA.t _A 'is calculated and, at a constant set room temperature, a new, lower outside temperature t _{amine is} determined (curve 3 of FIG. 2).

In the diagram according to FIG. 3 the daily routine in hours is shown in the abscissa and the temperatures are shown in the ordinate. The course of the actual room temperature is shown with a full line, the course of the target room temperature t _iN with a long dashed line.

The heating-up time Z _A lies within the reduction time Z _G , after which the room temperature is approximately at the target room temperature of + 20 ° C. In the lower part of Fig. 3, the course of the power (percentage) of the heat generator is shown.

Fig. 4 shows in a diagram how the factual heat requirement can be taken into account by measuring the time period between switching on the heater and switching it off for the first time by the boiler or flow temperature controller.

In the upper part of the diagram, the time course of the heating circuit temperature t _{v is} recorded in the abscissa. Line 5 denotes the temperature at which the heater switches on in the heated state by controller 25 and line 6 that temperature t _vmax at which it switches off. The heating takes place from the temperature t _vi .

In the lower part of the diagram according to FIG. 4, the power P of the heater is recorded in the ordinate, namely with point 7 the 100% nominal power. In the period Z _is the service provided heat can be established between the amount of input and the first off the heater and hence determine the correction factor by the calculated heating time Z _A to the actual switch-Z _is is taken into consideration.

The following cases must be considered when determining this correction factor be distinguished.

case 1

The heat generator was switched off before or with the reaching of the programmed start of the heating time, curves 2 and 3 in FIG. 4.

The changes in a large part of the outside temperature range Heating time is approximately linear with the outside temperature.  

The following relationship can be established between two curve profiles with different Δt _A :

Mean in it
Δt _AM the actual difference between the target room temperature t _iN and the actual minimum outside temperature t _Amin ,
Δt _AE the set difference between the target room temperature t _iN and the actual minimum outside temperature t _Amin ,
Z _AM the measured heating time - in Fig. 4 times for _Vin2 relation ship as z _in3 and
Z _{AE is} the heating-up time calculated from the setting data.

The ratio Z _AE / Z _AM can be used to correct the set value Δt _AE .

Case 2

The heat generator was switched off after the programmed start of the heating time, curve 1 in FIG. 4.

By extrapolating the flow temperature curve, the associated remaining on time determined.

wherein
Z _AM the actual switch-on time of the heat generator,
Z _{A is} the set heating time,
Δt _{vmax is} the difference between the maximum temperature of the heating circuit and the heating circuit temperature at the start of heating and
Δt _{vi is} the difference between the measured actual heating circuit temperature at the beginning of the time phase with the increased room temperature setpoint and the actual heating circuit temperature at the beginning of the time phase with the increased room temperature setpoint and the actual heating circuit temperature at the start of heating.

With this extrapolated value for Z _AM , the relationship is again established

the correction of Δt _{AE is} carried out. In this case, Z _AM corresponds to z _ein1 in FIG. 4.

Fig. 5 shows the diagram of a suitable heating system for carrying out the method with a burner-heated heater, for example a boiler 10 , a regulating the fuel supply to its burner 11 , arranged in a fuel supply line 12 , from a controller 13 via a servomotor or lifting magnet 14 adjustable valve and equipped with a circulation pump 16 , containing at least one radiator 17 , connected to the heat exchanger 18 of the boiler 10 , a flow line 20 and a return line 21 comprising heating circuit, in the flow line 20 a temperature sensor 19 is arranged. The control 13 of the boiler 10 , the drive of the circulation pump 16 of the heating circuit 20 to 21 and the temperature sensor 19 are connected via control lines 22 or 23 and 24 to a general control 25 of the heating system, to which also a device 26 for the arbitrary setting of the desired Desired room temperature t _iN , an outside temperature sensor 27 and a programmer 28 are connected via control lines 29 and 30 , 31 , respectively.

Input variables of this general control 25 are also a device-specific minimum outside temperature t _Amin and a building constant K _Geb proportional size K₁. A signal for detecting the state of the valve 12 is connected to the general control line 25 via a control line 36 .

In such a heating system, the duration of the heating time Z _A and consequently also the time for an automatic switch-on of the boiler 10 can be easily calculated by the controller 25 in the sense of the invention.

Claims (3)

1. Method for controlling the heating of rooms in a building which are set to a higher room temperature setpoint (t _iN ) than during a lowering time (Z _G ) during an occupancy time, the increased after the lowering time (Z _G ) Room temperature level should be reached again and the time period (Z _A ) is to be determined, from which the point in time at which a heater must be switched on in order to increase the desired room temperature (t _iN ) with the room temperature at the desired next start of occupancy to achieve, can be calculated, characterized in that the time period Z _A for the duration of the heating to the elevated room temperature level is determined according to the following relationship: With
Z _G as the time span of the deviation from the increased target room temperature t _iN in hours,
t _A as the actual outside temperature in ° C,
t _amine as the minimum outside temperature in ° C, at which the heat output required by the heating system, which is necessary to reach the set room temperature t _iN , is just covered by the output of the heat generator,
Δt _A as the difference between the set room temperature, t _iN and the minimum outside temperature t _amine in ° C and
K₁ as a dimensionless constant variable related to the time constant K _{Geb of} the building,
where the constant K 1 is determined according to the following relationship: with K _Geb as the building constant and A, B, C and n as further constants, whereby approximately applies: 2. The method according to claim 1, characterized in that the time period Z _AM from the beginning of the activation of the heat generator with the start of the heating time Z _A until the fol lowing first reaching the maximum temperature of the heating circuit, which is determined by the design data of the heating system, is measured and in the event that at the beginning of the time phase with the higher room temperature setpoint t _iN the heat generator has already been switched off via the maximum temperature, with the heating-up time Z _{AE used as} the basis for this heating-up process, and that the set difference .DELTA.t _AE between the set room temperature t _iN and the setting used as a minimum outside temperature t _amine in a range limited to low outside temperatures, within which the relationship between the heating time Z _A and the outside temperature t _{A is} approximately linear, is corrected in the following context : with Δt _AM as the actual difference between the room temperature setpoint t _iN and the actual minimum outside temperature t _Amin and Δt _AE as the set difference between the room temperature setpoint t _iN and the set minimum outside temperature t _Amin . 3. The method according to claim 1, characterized in that the period of time from the start of switching on the heat generator with the start of the heating time Z _A until the following first reaching the maximum temperature of the Heizkrei ses, which is determined by the design data of the heating system, is measured and in the event that at the beginning of the time phase with the higher room temperature setpoint t _iN the heat generator has not yet been switched off above the maximum temperature, the actual heating-up time Z _{AM is} calculated from the following relationship: where Z _{A is} the heating-up time calculated from the set difference Δt _AE , Δt _{vmax is} the difference between the maximum temperature of the heating circuit and the heating circuit temperature at the start of heating and Δt _{vi is} the difference between the measured actual heating circuit temperature at the start of heating up, which means that it calculated Time Z _{AM is} set in relation to the heating time Z _{AE used} for this heating process, and that the current difference Δt _AE between the desired room temperature t _iN and the minimum outside temperature t _Amin in a range limited by low outside temperatures , within which the relationship between the heating-up time Z _A and the outside temperature t _{A is} approximately linear, is corrected according to the following relationship: