DE1295160C2 - DEVICE FOR CONTROLLING THE CHARGING OF HEAT STORAGE ROOM HEATING STOVES, IN PARTICULAR THOSE WITH ELECTRIC CURRENT AS ENERGY CARRIERS, WITH HEAT ENERGY IN CHEAP PERIODS - Google Patents

Description

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Device for controlling the charging of heat storage space heating stoves, in particular such with electricity as a source of energy, with heat energy in low-cost periods.

When charging heat storage space heaters that are powered by electricity or by Charged with another heat transfer medium are not only those approved by the energy supplier Charging times must be taken into account, but it is also necessary for economical heating to use the storage heater in the charging time - the main charging time is usually between 10 p.m. and 6 a.m. - only so far to charge the amount of heat that is expected to be required the next day. Furthermore it is It is advantageous to control the charging process in such a way that charging only takes place at the end of the approved charging time, d. H. at the beginning of the discharge time, is available in full. In all other cases it would be unnecessary Energy consumption due to unavoidable heat emission occur at the wrong time.

The invention relates to an apparatus for controlling such charging.

It is already through the German patent specification 11 28 105 a method for controlling the charging of heat storage known, which said this as necessary for economical heating Measures. It uses the outside air temperature as a control variable. Point of time the beginning of the charging process is such that charging is only carried out at the end of the respective low-cost period is finished.

This procedure has the serious disadvantage that the in the storage heater from the previous heating period z. B. due to an increase in outside air! temperature remaining residual heat is not taken into account, so that it leads to uneconomical overloading can come. Another disadvantage is that the outside air temperature by means of a thermal expansion element established and transferred to a shift cylinder via a mechanical linkage will. Such mixed mechanical-electrical elements are naturally very sensitive and a Subject to constant wear, so that constant maintenance is required.

A suggestion to solve the above-mentioned problem in a purely electrical way can be found in the earlier patent 12 50 027, which relates to a charger for storage heaters in which the outside air temperature is represented by an electrical, temperature-dependent resistor, which is such works that lower measuring temperatures are associated with increasing resistance values, and the with a given constant resistance and with a clock or an electromotive Timing driven rotary resistance (potentiometer) with increasing or depending on the Circuit also with decreasing resistance characteristics interconnected to form a Wheatstone bridge in which the resistance values are compared with each other and by the change in the bridge equilibrium Control processes are triggered that cause the charging current to be switched on.

In this device, which works with individual elements known per se, the remains in the memory Any remaining residual heat is not taken into account, so that it is also here at the end of the charging period inefficient overloads can occur. Another disadvantage of this device is that there are curved families of curves for the control due to the bridge circuit, which only have a fairly straight course in the middle area, while the initial and End areas are rather curved and give rise to inaccuracies in the charging.

Through the DT-PS 6 39 252 a control device for a storage device is known that the previous day Residual heat remaining in the storage tank is recorded and taken into account as a control variable during charging. The storage device will if there is any residual heat

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accordingly switched on later, so that the end of the charging time around the end of the cheap time period coincides. The outside temperature is not recorded with this device. The control takes place also via mechanical elements that act on mercury switches. This results not only those mentioned above, which inevitably occur with mixed mechanical-electrical construction Disadvantages, rather, the control itself becomes inaccurate because the mercury switch "gradually" work and have only a few switching steps.

The invention has set itself the task of a purely electrically operating device like her the subject of the earlier patent is based on increasing the accuracy of the control, wherein in particular, the end of the charging process also coincide with the end of the cheap time period should if there is still a more or less large amount of residual heat in the storage core at the start of charging is available.

The solution to the problem is that in addition to the outside air temperature, that of the previous one Charge-discharge period and residual heat remaining in the heat accumulator is detected as a control variable is represented by an electrical, temperature-dependent resistor, which also works in this way that lower measuring temperatures are associated with increasing resistance values, and that the temperature-dependent Resistors and the rotary resistor are connected in series, with the control operations then triggered when the sum of the resistance values of the variable resistances corresponds to the resistance value of the given constant resistance.

In the case of the invention, too, there are disadvantages

mechanically or mechanically-electrically working elements avoided. But due to the Series connection of the resistances (summation) sets of curves with a straight course achieved, the result in a more accurate working of the charger even in extreme areas. By attraction the residual heat as a control variable is any residual heat remaining in the storage tank Charging is taken into account so that there is no

ίο unwanted overloading can occur.

One embodiment of the subject matter of the invention provides for the outside air temperature indirectly via the temperature of the wall surface of the object to be heated facing the outside air measure up. This measure leads to the fact that in the determination of the heat demand in the wall of the the object to be heated is taken into account; only from the outside air temperature can be assumed, especially if this

changes quickly, leading to incorrect assessments of the heat demand. Another embodiment provides for the use of semiconductors for the temperature-dependent resistors. This will the maintenance-freedom of the device is increased.

In the following, to explain the operation of the device according to the invention, the theoretical Basics communicated, whereby it should be noted that with the variable resistances in place of those with increasing resistance characteristics, of course, there are also those with decreasing resistance characteristics, and indeed for all of them at the same time, are used can.

The resistance values mentioned are, as shown, summed in a measuring circuit. this can be expressed in the following equation:

weather

Residual heat

Loading time constant

The individual summands are made up as follows:

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1. The weather resistance value consists of the

a) Fixed resistor R _where , e.g. B. related to 20 ° C building wall temperature,

b) variable value Δ t _w ■ <x ", in which Δ t _{w is} the temperature difference compared to 20 ° C = t" - 20 "C, a _{w is} the temperature coefficient (Ω / ° C).

2. The residual heat resistance value consists of the

a) Fixed resistance value R ₀₀ , e.g. based on 20 ° C storage surface temperature (instead of the furnace core temperature, which is difficult to measure),

b) variable value Δ t "■ t \ _q , in which A t _{q is} the temperature difference compared to 20 ° C = f, - 20 ° C,

a _{Q means} the temperature coefficient (Q / ° C).

3. The charging time resistance value consists of the

a) Fixed resistance value R _{h0 of} the potentiometer at the time of the charging time release, e.g. B. 10 p.m.

b) variable value Z ₁ , ■ & _h , in which Z _h time interval in hours (blocking time) after the release of the tariff preferential charging time, z. B. after 10 p.m., and α _{Λ means} the change in resistance per hour.

4. K is a given fixed resistance.

Depending on whether the variable portions of the first two summands are larger or smaller, corresponding to a smaller or larger weather or residual furnace heat temperature, the value Z _h (switch-on period after 10 p.m.) is smaller or larger; that is, the charging of the heat storage begins earlier or later accordingly.

If the above equation is used for the values R _w0 to K, the numerical values given by the measuring resistors and selected accordingly for the other resistors and solved for Z _1x , the equation for the start of the charging time after 10 p.m. is obtained

Z "= 1.320 + 0.200 ^

where only t _w (the building surface temperature) and t _q (the storage surface temperature) have to be used.

Examples

1. With a t _w = + 20 ° C and a t _q of 20 ° C (transitional season), Z _h = 8 hours, so charging can only start at 6 o'clock in the morning at the end of the approved charging time, ie it takes place no storage takes place at all.

2. With a t _w = 0 ° C and a /, of 20 ° C (mean winter conditions), · Ζ _Λ = 4 hours, ie the charge would have been over

2 o'clock start.

3. In a t _w = - 20 ⁰ C and a / "from 2O ⁰ C (severe frost) would Z _n = 0 hours, respectively, that is, the charge would immediately begin at 22 o'clock at the time of release.

4. For a t _w = - 20 ⁰ C and a t "of 4O ⁰ C (severe frost, but the residual heat in the furnace) would be Z _h = 2.7 hours, ie, the up ^ao charge would 0.42 Start clock.

If the outside air temperature increases after the start of charging, in the case of Invention immediately interrupted the charge. The scheme according to the invention therefore acts at the same time al; Overload protection.

A device operating according to the above equation is shown schematically in the figure

1 denotes the resistance of the immediate The outside sensor located on the building wall, 2 the resistance of the one located on the storage heater 9 Residual heat sensor, and 3 the resistance of the rotatable potentiometer, which is set via the Axis 4 ″ is adjusted by a clock or some other electromotive timer 4.

The resistors mentioned are connected in series. Their sum is within the measuring circuit 5 which is fed by a constant voltage source 7, with a predetermined constant resistance Π compared. If the two values match, control processes are triggered that enable the of the charging switch 6, which attaches the network 10 to the storage heater 9.

λ- ⁰⁰ W ^{patent protection} covers only the features of each claim in their entirety, including the withdrawals.

1 sheet of drawings

Claims (3)

Patent claims: 1. Device for controlling the charging of heat storage space heating stoves, in particular of those with electricity as an energy source, with thermal energy in low-cost periods, in which the outside air temperature is continuously used as a control variable and in which the The point at which charging begins is automatically adjusted so that only at the end of the respective low-cost period the charge is finished, at which the outside air temperature is also determined by an electrical, temperature-dependent resistor is shown, which works in such a way that lower measuring temperatures increasing resistance values are assigned, and those with a predetermined constant Resistance and a rotary resistance driven by a clock or an electromotive timer (Potentiometer) with increasing resistance characteristics to a measuring circuit is interconnected, in which the resistances are electrically compared with each other and which trigger control processes when a certain comparison value is reached, the actuation of the access of the energy carrier to the heat storage device cause, characterized in that in addition to the outside air temperature also that of The residual heat remaining in the heat accumulator during the previous charge-discharge period as a control variable detected and represented by an electrical, temperature-dependent resistor (2) which also works in such a way that lower measuring temperatures increase resistance values are assigned, and that the temperature-dependent resistors (1, 2) and the rotary resistance (3) are connected in series, the control operations being triggered when the sum the resistance values of the variable resistors with the resistance value of the given constant resistance (11) matches. 2. Apparatus according to claim 1, characterized in that the detection of the outside air temperature in a manner known per se indirectly via the temperature of the outside air Wall surface of the object to be heated takes place. 3. Apparatus according to claim 1 or 2, characterized in that the temperature-dependent Resistors consist of semiconductors in a manner known per se.