DE2720526A1 - METHOD AND DEVICE FOR REGULATING A HOT WATER HEATING SYSTEM OF A BUILDING - Google Patents

Description

- 5 description

Method and device for regulating a hot water heating system in a building

The invention relates to a method and an apparatus for controlling a hot water heating system in a building.

The normally used control systems consist of a linear dependence between the current outside temperature te and the flow temperature td of the water supplying the radiators (cf. Fig. 1a, 1b).

This procedure poorly expresses the complexity of the phenomena involved. This is e.g. the emission curve the radiator is not linear depending on the temperature of the supply water.

In addition, the outside temperature is not the only disturbance variable in the dsm expression for the heat balance of the rooms. The heat input resulting from solar irradiation takes part in this balance and often results in unpleasant effects Changes in the internal temperature after calibration.

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The majority of the traditional regulations represent the Sun exposure is not billed and those who bill for it do so only imperfectly.

If it is possible to compensate momentarily the solar heat input, which is smaller than the heat loss, by reducing the heating as much, it is no longer the same when these inputs become more substantial. The heating would be switched off, but the additions to the solar supply are not recorded; or these are not negligible. This results in overheating of the rooms and a waste of energy.

A traditional regulation based on the linear dependency has no storage function and can therefore do not remember previous actions. If, for example, the flow "tempera door of the water is greater than the intended, the regulation does not charge for this later. It can only be the relationship of one temperature to another Ensure temperature.

Eb is therefore indispensable in traditional systems that the flow temperature strictly follows the outside temperature. However, this is difficult to achieve in practice because of the limited accuracy of the mixing valve, which is more or less less long response time and the more or less good stability of the control loop and the more or less rapid and more or less significant changes the water temperature of the boiler. One often meets systems in which the dynamic differential or * error signal

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- 7 of the AQuastaten of the boiler greater than 15 ° C iat.

The present invention is directed to a method of regulating a hot water heating system of a building and a device for carrying out this method directed the are characterized in that the controller has a computer which continuously supplies the current heat balance, that of the difference between the heat losses of the building on the one hand and the heat input due to heating and the solar irradiation on the other hand, an integration memory that accumulates the current balances, a device for periodic polling of the memory, a control element that corresponds to the state of the memory acts on the device for regulating the heating flues Q ^ T (Q denotes the flow rate of the water that circulates in the entirety of the radiators, and AT denotes the waste the water temperature through all of the radiators), such that within the at least two consecutive Surveys separating time intervals the accumulated balance is deleted.

Further advantages, features and possible applications of the present invention emerge from the following Description of exemplary embodiments in conjunction with the drawing. Show in it:

1a shows a heating system which is controlled by a linear regulator,

Pig. 1b the change in the flow temperature as a function of on the outside temperature according to a linear relationship,

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Pig. 2 a hot water heating system which is controlled by a control system based on the continuous query of thermal balances according to the invention,

Pig. 3 shows a symbolic diagram of a control device according to the invention,

Pig. 4 the scheme of a step-by-step control of the servo motor driving the mixing valve,

Pig. 5 is a symbolic scheme of a modified embodiment the electrical circuit of the control device according to the invention,

6a shows an exemplary embodiment of a step-by-step control of the servomotor with limitation of the regulated flow temperature to the outside temperature,

Pig. 6b the curve of the limit flow temperature in the case of Pig. 6a,

7a shows an exemplary embodiment of a step-by-step control of the servomotor with limitation of the regulated return temperature to the outside temperature,

Fig. Tb the curve of the limit return temperature in the case of Fig. 7a,

8 shows the scheme of a control circuit according to the invention, which is adapted to reduce the internal temperature of the rooms during the night »

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The following terms and designations are used in the description and the figures:

a) Temperatures

te: Current outside temperature

td: flow temperature of the heating water tr: return temperature

Tq: target temperature

T-n: Minimum outside temperature for which the system calculates has been

T-jj-g: Forward tempera door of the water when the outside temperature is equal to Tg

TjJ ₀ : Flow temperature of the water for te = Tq T ™ .: Return temperature of the water for te = Tg T _RC : Return temperature of the water for te = T "

b) Elements of an installation

Ch: boiler or generator for the production of hot water V.M.: three-way mixing valve, which the return water mixes with the water coming from the boiler. This is

So the control device of the heating flow. SM: Servo motor to control the mixing valve. It has two directions of movement, which are marked with "+ warm" and ^w - warm "

are designated.
F: circulation pump, which has a constant flow rate Q

of the water in the radiators. Wheel: radiators or radiators
Reg: regulator
Tjj: sensor for measuring the _{flow temperature of the water T R} : sensor for measuring the return temperature of the water Τ- ,: sensor for measuring the outside temperature te

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- ίο -

Τς .: feeler, which the influence of the solar radiation is exposed to measure a temperature ts. The solar radiation is determined by the difference ts-th measured.

In Fig. 1a a known control device is shown, which obeys the linear law and regulates the flow temperature td of the water according to the outside temperature te.

The circuit has a boiler Ch, which is connected to a radiator wheel (which controls the various heating devices of a Apartment has) via a mixing valve VM and a circulation pump P is connected. The return is made directly from Radiator wheel to boiler Ch. Part of the return water is drawn off and after metering through the mixing valve VM sent back to the circle.

The outside temperature te is picked up by a sensor T-g and the flow temperature td of the water is taken from a sensor TjJ, which is located at the input of the radiator wheel is arranged. These two quantities are introduced into a controller which, in accordance with the following law is programmed:

td = f (te)

This controller controls the servo motor SM of the misoh valve VM, that doses the amount of return water with the temperature tr that is to be mixed with the flow water.

In Fig. 1b, the change in the flow temperature td in Depending on the outside temperature between the basic

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temperature T _ß (given) and the setpoint temperature T ~.

The needs of a building depend on a certain number of climate parameters, of which the outside temperature, the sun and the wind are the most important. In the well-sealed and insulated buildings, the Influence of the wind can be neglected. Only the outside temperature and solar radiation play a significant role Role.

The heat balance of a building includes:

The heat losses due to the difference between the indoor and outdoor temperatures,

the solar heat supplies,

the heat input due to the heating,

the inner feeders.

The internal supplies are taken into account:

Either in the area of the room through additional control depending on the interior temperature, if the heating system is provided with such devices. The setpoint temperature of the central controller is regulated to a value which is at least equal to the internal temperature T "= Ti,

or as a lump sum through centralized regulation, if the system does not have any

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has additional regulations depending on the environment. When Δ Ti denotes the temperature rise obtained by the internal supplies, the set temperature is regulated to the following value:

TC = Ti - Δ Ti

It is not always possible to balance the heat balance momentarily, because the solar heat supply, e.g. at certain hours of the day, exceeds the losses to a large extent can. It is therefore necessary to be able to postpone the compensation of the heat balance. This can Fortunately, without any negative impact on comfort, because the heat capacity of the building means that the Changes in outside temperature, solar radiation and the energy supplied by the heating system do not immediately detect the internal temperature have an effect.

The energy to be supplied by the heating system is such that it depends for a more or less long time interval the following equation is fulfilled by the thermal inertia of the building:

^> r ~ Through the heating r ~ heat losses of the Γ ~ "solar system \ building supplied due to \ heat-heat flow = ) the difference - L · supply

/ Between indoor and outdoor temperature I-

In order to simplify the illustration, the following is the case of a rectangular building with a heating system designed differently due to the Äasade.

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The following designations are used for half the building considered used:

G: Volumetric heat loss coefficient in W / no / ° C.

Sv: glazing area of the passage in m.

V: Habitable volume of half the building under consideration in m.

f: solar factor of the glass windows.

R: Solar irradiation hitting the Passade in W / m ² .

Q: Volumetric flow rate of the water supplying all the radiators in m / sec.

G: Volumetric heat of water in J / m / ⁰ C.

The solar supplies per unit of habitable volume are the same:

f Sv χ R
ΊΓ

The heat supplies due to the heating have pro habitable Volume unit the following value:

(td - tr)

The heat losses per habitable volume unit are:

G (Tc - te)

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-H-

The regulatory law can therefore be written as follows will:

(td -tr) dz = \ G (T _n - te) dz - (f Sv. Rdz

Here the variables are:

te: Measured by the outside temperature sensor.

R: Measured by the solar radiation sensor.

(td-tr): Measured by the sensors for the flow and return water of the heating system.

z: The time.

The parameters G, Sv and V are the characteristics of the building.

The product Q.C is considered constant.

The flow of the hot water can be viewed as constant with a great approximation, so that it does not come from a Durohflußmeßgerät must be measured.

If this is not the case, it is sufficient to measure the flow with a suitable measuring device and measure it no longer to be regarded as a fixed parameter.

In Fig. 2, a heating device with a control according to the invention is shown, which on the continuous integration of the heat balances.

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The heating circuit has a boiler Ch, a radiator wheel, a mixing valve VM with its servo motor SM and a circulation pump P on.

The outside temperature and the solar radiation temperature are measured by two sensors Te and Ts.

The flow temperature Td and the return temperature Tr are taken before and after the radiator by sensors T- ^ and T _ß . The parameters are integrated in the Reg controller, in which the following values are displayed:

The target temperature Te,

the water flow per living volume Q, the volumetric heat loss coefficient G and the ratio f Sv.

In Fig. 3, the control system according to the invention is shown.

An analog computer 1 has the following elements:

A sensor T ™ that responds to the outside temperature,

a sensor Tg which measures the solar radiation temperature appeals,

a rheostat Tc, with which the device a target temperature can be entered,

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2720 ^ 26

a sensor T ^, which responds to the flow temperature of the heating water in the entirety of the radiators,

a sensor T _R , which responds to the return temperature of the water after passing through the radiators.

The sensors Τ _£ and Tg, which are arranged in a bridge circuit, are connected to a comparator A ^ , which in turn is connected to an amplifier E .. which provides the temperature difference supplied by the comparator Δ * with a coefficient that is determined by a in a negative feedback circuit arranged potentiometer is supplied.

The sensor Tg is also connected to a comparator Ao, as is the rheostat Tc. The comparator Δ ο ^ - ^Β ^ connected to an amplifier Ep which is provided with a negative feedback circuit which has a potentiometer through which a coefficient is fed.

The sensors T _R and Tp are connected in the same way in a bridge and connected to a comparator Δ ■ * , which is followed by an amplifier E, with its mutual coupling circuit.

The three amplifiers E .., Ep and E are connected to the input of a summer Σ .

The signal coming from the adder Σ is integrated in a numerical integrator 2, which is connected to a memory 3 connected is. The memory 3 is connected on the one hand to a pulse generator 4 and on the other hand to two relays, one of which one a breaker C. and the other a breaker C controls.

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These serially arranged breakers control the operation and direction of operation of the motor M, which causes the rotation of the mixing valve that controls the temperature of the water entering the radiators.

The principle of the regulation is as follows:

1) The analog computer 1 creates an instantaneous power balance as a function of the variable quantities (te, R, td and tr) and the fixed quantities (G, T _p , f Sv, Q «C ) and supplies a voltage proportional to this balance.

= G (T ₀ - te) - (JC (td-tr) + f Sv * R dz VV

2) The storage integrator (2, 3) continuously adds up the current power balances:

dz

3) The memory is queried periodically (eg every five minutes) with the help of the transmitter 4. The state of the memory at the time of the query represents the heat balance of the building. Depending on the application, the desired level of information will be more or less complete. In certain cases, the required information is simply to know whether the heating is ahead of requirements (φ here is less than 0) or behind (φ is here> 0). Detecting the sign of φ is therefore sufficient. In Pig. Such an exemplary embodiment is shown in FIG.

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In other applications (not shown here) it might be necessary to know the exact value of φ. Incidents can also be taken into account, for example knowing whether Φ is outside or within a dead zone determined by two values + L and - C. It is noted that it is necessary to limit the capacity of the memory.

If, for example, the heating of a building is switched off for ten days, it would be absurd to say that the energy which the heating must first compensate when _{restarting corresponds to the integral of the heat losses G (T ß-} th) that during the previous ten days has been measured by the scheme. In this case, the fixed setpoint temperature T " (T _c = 2O ⁰ C for example) no longer corresponds to the actual internal temperature Ti. After the heating has been switched off, this internal temperature gradually becomes equal to the external temperature at the end of a certain period of time, depending on the cooling time constant of the building.

In practice, the integral φ =) Δ φ dz has two symmetrical or non-symmetrical limit values. One corresponds, for example, to the integral of the heat losses during a momentary shutdown of the heating (priority is given to the production of hot water for sanitary facilities by turning off the heating; turning off the heating during part of the night, etc.). The other limit corresponds, for example, to the integral of the solar inputs that the building can effectively regain without compromising comfort.

4) Depending on the information received about the status of the memory, the controller acts on the

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direction for regulating the heating flow ψ Α Τ in such a way that the integral ^ = (Δ, ψ dz is deleted as quickly as possible.

In the exemplary embodiment cited, the controller acts on the mixing valve by controlling the servomotor step by step in the "+ warm" direction when φ *? O, and in the "-warm" direction when φ ^ - O.

In Fig. 4 the control circuit of the servo motor is shown.

The changeover contact G ₁ , which determines the direction of rotation of the servo motor SM, is in the "+ warm" position when the sign of the integral j ^ ψ dz is positive, and in the "-warm" position when the sign of the preceding integral is negative .

The contact Cp determines the running time Z _{1 of} the servomotor within the period Z _Q , which represents the time interval that separates two successive surveys of the memory.

The ratio Z ₁ is fixed in the described embodiment.

However, it can be regulated according to the absolute value of the integral | Δ ψ dz if it is desired that the operating speed of the servomotor increases with the amplitude of the imbalance in the balance.

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- 20 The regulatory act in its general form

£ CJ (td-tr) dz = Gj (T _Q -te) dz - f Sv j Rdz

links four parameters on the controller (T _n , G, QC and f Sv),

which complicates the regulations a little at the start, all the more since the parameters G and Q are often used in existing buildings are poorly known.

After dividing by G one obtains from the previous equation

Kr Γ (td-tr) dz = ( (T _Q -te) dz - Ks j ^ Rdz with

Kr = QC and Ks = f · Sv GV GV

The parameter Kr is nothing other than the ratio Kr = Tc - T-o

nominal Tq denotes the target temperature.

Tjj denotes the outside temperature for which the system is calculated.

Δ T nominal is the temperature drop of the water that continuously circulates in the radiators when the outside temperature is equal to the basic calculation temperature. These values are

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known with considerably greater accuracy than the values of G and Q. Since the parameter Kr is the essential parameter of the scheme, it is important to match it with the highest possible Determine accuracy.

As for the parameter Ks, which represents the compensation of the solar heat input, it is lower Meaning. It is naturally relatively imprecise due to the coefficient f (solar factor of the glass window). The at Errors made in estimating the coefficient G are therefore less important in calculating Ks than in the calculation of Kr. Therefore, there is an interest in being able to determine Kr using the indirect method described above.

In Fig. 5 the principle scheme of the control is shown, which is completely the same as the principle described in the above representation (see. Fig. 3). In this Fig. 5 correspond to the amplifier E _1, and E ,, the amplifiers E ₁ and E of FIG. 3. The coefficients with which of the comparators A _1. and Δ -ζ are provided outgoing signals have become Ks and Kr, respectively. These coefficients are obtained by dividing the _{coefficients assigned to the amplifiers E 1} , E «and E by the factor G, the amplifier Eg, which now has the coefficient 1, is omitted.

It is sometimes necessary to keep the flow temperature td below of a certain threshold value in order to e.g. the noise problems due to too fast and too frequent Avoid changes in the temperature of the water supplying the radiator. In the regulation law described above, nothing limits this temperature outside the aqua

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state of the boiler. But nothing prevents you from doing it to do.

The accumulated balance sheets are now deleted by that the flow temperature is below a certain fixed or variable value.

In Pig. 6a the case is shown in which it is desired that the flow temperature as a function on the outside temperature according to the straight line A of the Pig. 6b is limited.

The control circuit of the servomotor has a reversing contact L. This contact is in position 1,2 when the flow temperature td is below straight line A for an outside temperature te. This represents normal operation.

When the flow temperature exceeds straight line A, it opens the contact L connects the circle 1,2 and makes the connection 1,3, which puts the servomotor in the less warm position is returned.

With geothermal heating, it is important to use one to work as large as possible temperature difference between the extraction and re-injection of the geothermal Water. Since the temperature of the recovered water is constant, the temperature of the water must be before its Re-injection can be monitored. This pail will the control mode is set to the return temperature tr.

In Pig. 7a is an embodiment with one limitation

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the return temperature door depending on the outside temperature shown.

The contact L closes the circuit 1,2 when the return temperature tr for a given outside temperature te below curve B (normal operation). (Fig. 7b).

If the flow temperature is above curve B, undercut the contact L makes the circle 1,2 and connects 1,3, which puts the servomotor in its less warm Position is returned.

The maximum mean temperature of the living space is set at 2O ⁰ C. In the case of existing buildings with a large proportion of glazed surface, a daytime temperature of 21 ^° C. is often required. In contrast, users prefer lower temperatures at night.

The general problem with heating is therefore to ensure a feeling of comfort for the day and night, taking into account the regulation. The scheme will reduce the night temperature, to increase the daytime temperature, wherein it is assured that does not exceed 2O ⁰ C over a whole day (24 hours), the average indoor temperature.

A conventional control system without a storage tank does not make it possible to strictly control this mean temperature. More or less complicated and more or less precise solutions have been developed to solve this problem. The most commonly used solution is the following:

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- 24 _
The control has three heating cycles.

1) A normal range from 8 a.m. to 11 p.m.

2) A slowed down area from 11pm to 6am.

The beginning of this section coincides with the end of the television broadcasts together. The lowering of the setpoint of the regulation is in the order of 3 to 5 ° C.

In spite of this lowering, the heating continues, with the energy sent to the radiators being proportional to the difference between the slowdown temperature and the outside temperature. From this it follows that the actual nighttime temperature drop is less than that which is determined by the slowing down or than that which is obtained by the natural cooling of the apartment when the heating is switched off. The users have a tendency to open the windows of the rooms for fresh air. This results in over-consumption. This is confirmed by various studies carried out in situ, in the course of which it was found that the consumption due to the difference between the indoor and outdoor temperatures increases by about $ 10 at night.

3) An accelerated range from 6 a.m. to 8 a.m.

This time period is set according to the professional ones Activities of the residents. The goal of this accelerated area is to try to do that Partial losses of the energy output during the night are compensated in order to compensate for any temporal drift in the internal temperature avoid that would result in his absence.

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Unfortunately, this compensation is very imprecise. The regulation did not determine the energy losses during the night; they also do not charge the during the Excessive power delivered over the entire duration of the accelerated range.

With the present control it is possible to switch off the heating e.g. from 11 p.m. to 6 a.m. Through this a more significant drop in internal temperature can be achieved. Thanks to the storage of the balances remembers the regulation on the other hand when resuming 6 o'clock in the morning to the losses or the lack of energy output during the night. Sowing therefore first catches up on this backlog by using all of the available power. if then the equilibrium of the balances is reached again, regulates them depending on the immediate needs.

On very cold days the heating is switched off 11 p.m. to 6 a.m. may be too long for the heater to recoup all of its losses. It it is therefore desirable to be able to reduce the heating interruption time. This is with the help of the arrangement according to Fig. 8 possible.

Contacts C ₁ (1 C ₁ , 2 C ₁ ) C ₂ and L operate in the same manner as those shown in FIG. In particular, the contact 2 C ₁ closes (making the connection 7, 8) only when the accumulated balance is zero or negative (the heating is ahead of the needs).

Contact H (time contact) is closed between 11 p.m. and 6 a.m.

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So that the relay C ,, which the contacts 1 G, and 2 C, controls, is excited so that the contact 2 C, the connection 4.5 interrupts to establish the connection 4.6 and turn the servomotor in the "- warm" direction until the heating of the rooms is stopped two conditions required:

1) That the time or switching contact is established (in the exemplary embodiment 23 to 6 o'clock).

2) That the contact 2 C _{1 is} made, ie the heating is ahead of the needs.

Only when these two conditions are met is it possible to switch off the heating during the night.

The contact 1 C, is a self-holding contact, the influence of contact 2 C. eliminated when relay C- is switched on has been.

Instead of switching off the heating during part of the night, it is also possible to reduce the setpoint temperature be made. In this case one would have two setpoints have ι

One with Τ ~. designated target temperature, which is the mean The temperature of the building is determined for an entire day (24 hours). The building losses are always in proportion determined for this target temperature.

A setpoint temperature labeled T, ™, which is the maximum Energy determined by the heating during the reduction period is delivered.

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Claims (12)

ηπ. DIETEU ν. »Εζοι.η DIPL. IN O. PETEH SCHÜTZ DIPI ,. ING. WOLFOANO II COOLER MARIA-TnRRRRIAHTRASfIB IS POST BOX ΗβIM) β « »-8,000 MUKNCIIKN ββ TBLBFOX «Τββ19 TKLKX BMMS TBLBHRAMM SOMBBB CEM 1462D
10057 / Al
FR-PA 76 13726
AT. May 7, 1976 CEM - Compagnie Electro-Mecanique, 12, Rue Portalis, Γ-75383 Paris Cedex 08 Method and device for regulating a hot water heating system of a building Claims M. ^ Procedure for regulating a collective heating system of a Building with hot water that circulates in radiators, which with the help of a control device for the heating flow which controls the circulation of the water exiting the radiators, characterized in that that the current heat balance of a living. volume created by the difference between the heat losses of the housing on the one hand and the heat input due to the heating and solar radiation on the other hand is formed by the outside temperature, the solar radiation temperature, the flow temperature of the water in the radiators and the return temperature of the water after the radiators are measured the current balances are accumulated in a memory that is periodically queried and provides a signal that acts on the control device of the heating flow, such that within the at least 709845/1104 GIAL INSPECTED separating two successive interviews Time intervals the accumulated balance is deleted. 2. The method according to claim 1, characterized in that the current balances accumulating storage capacity is limited to an upper and lower value is dependent on either the maximum acidity of the heating shutdown or the maximum recovery of the solar supply or both. 3. The method according to claim 1, characterized in that the information supplied by interrogating the memory indicates the sign of the accumulated balance sheet. 4. The method according to claims 1 to 3, characterized in that the control of the control device of the Heating flow takes place gradually. 5. The method according to claim 1, characterized in that j the upper flow temperature of the heating water is limited depending on the outside temperature. 6. The method according to "claim 1, characterized in that the upper return temperature of the heating water is limited depending on the outside temperature. 7. The method according to defl claims 1 and 2, characterized in that during the total duration of the partial or total shutdown of the heating always estimated in relation to the target temperature which determines the mean temperature of an entire 24-hour day. 8. The method according to claims 1, 2 and 7, characterized in that the reduction in the internal temperature achieved during the night by a total shutdown or a partial reduction of the eeitprogrammed heating and the beginning of the shutdown of the heating or its reduction also regulated on condition that the accumulated balance is zero or negative. 9. The method according to claim 1, characterized in that the instantaneous and accumulated heat balances divided by the volumetric loss coefficient of the building. 10. Control device for a heating system for implementation of the method according to claim 1, characterized by a computer (1) continuously delivering the current heat balance, an integration memory that collects the current balance sheets (2, 3), a device for periodic polling of the memory and a control element which, according to the state of the memory, acts on the control device of the heating flues in such a way that! within the time interval separating at least two successive interviews the accumulated balance sheet is deleted. 11.Vorrichtung according to claim 10, characterized in that the computer has the following part · has t 709845/1104 Measuring elements for the outside temperature, the solar radiation temperature, the flow temperature of the water in the radiators and the return temperature of the water after the radiators, a Verg] ei _c forth, which forms the difference between the radiation temperature and the outside temperature, a comparator that shows the difference between the outside temperature and the setpoint temperature, a comparator that calculates the difference between the flow and return temperatures of the water, Control amplifier for the application of the comparators supplied differences with coefficients and a summer which forms the sum of the signals sent out by the amplifiers. 12.Vorrichtung according to claim 10, characterized in that the control member consists of a mixing valve, which is provided with a servo motor and dosed in the circulation of the return water of the radiator in the inlet circuit. 709845/1104