DE102004042972A1 - Thermal solar system regulating method, involves predicting solar output of solar system to optimize supply sequence of solar output during different consumptions, and determining best variant by technical parameter of heat pump - Google Patents

Abstract

The method involves predicting solar output of a thermal solar system at another temperature over heat quantity and collector temperature. The prediction serves for optimization of the supply sequence of the solar output, during different consumptions. The optimization takes place with respect to the power consumption. A best variant is determined by a technical parameter of a heat pump depending on heating water and source temperature.

Description

• • Die Warmwasserbereitung mittels Solaranlage ist mit höheren Temperaturen möglich (Legionellenbekämpfung und Komfort)
• • Der Wärmebedarf eines Hauses geht immer weiter zurück, so daß die Warmwasserbereitung einen immer höheren Anteil einnimmt. Diese Warmwasserbereitung erfolgt bei Wärmepumpenheizungen durch die höheren Temperaturanforderungen mit schlechteren Leistungszahlen als die Gebäudeheizung.
• • Große thermische Solaranlagen können zusätzlich dazu verwendet werden, solare Erträge direkt in die Heizung einzuspeisen bzw. der Wärmepumpe als Quelle zu dienen. Das bietet folgende Vorteile: – Überhitzungsschutz für den thermischen Kollektor – Speicherung von Solarwärme bei geeigneten Untergrundverhältnissen – Erhöhung der Quellentemperatur beim Wärmepumpenbetrieb, um durch die höhere Quellentemperatur die Leistungszahl sowie die thermische Abgabeleistung zu verbessern – Erdabsorber auf kleinen Grundstücken können wieder regeneriert werden, um einer zunehmenden Vereisung entgegenzuwirken

With the decreasing heat demand of houses, the rising operating costs for conventional heating as well as the new energy saving regulation, the boundary conditions for the use of heat pumps for house heating in Germany are getting better and better. However, many builders not only opt for a heat pump heating, but also for a thermal solar system. Besides environmental protection and technical interest, this has very practical reasons:

• • Hot water preparation by means of a solar system is possible with higher temperatures (combating legionella and comfort)
• • The heat requirement of a house goes back and forth, so that the hot water preparation occupies an ever higher proportion. This hot water preparation takes place in heat pump heating by the higher temperature requirements with poorer performance than the building heating.
• • Large solar thermal systems can also be used to feed solar energy directly into the heating system or as a source for the heat pump. This offers the following advantages: - Overheating protection for the thermal collector - Storage of solar heat in suitable substrate conditions - Increase the source temperature during heat pump operation to improve the coefficient of performance and thermal output through the higher source temperature - Earth absorber on small plots can be regenerated to a to counteract increasing icing

Of the Solar yield of solar panels is at low temperatures much higher in the collector. This makes it possible Collectors with very high yields to operate (e.g., at 10 ° C Collector temperature) and these yields of the heat pump as a cheap source of energy supply.

Heat pumps and solar systems therefore fit together very well.

For this combination, however, no suitable regulations are available. The usual procedure is as follows:
The regulations for heating and solar system work independently of each other:
Temperature difference controls switch on the solar circulation pump when higher temperatures are achieved in the collector than in the considered consumer. Here, priorities are preset, which consumer should be served as a priority.

If the temperature for the first consumer, e.g. the hot water, not enough, if another consumer is being served, e.g. the heating, a swimming pool or the earth absorber. In principle, it is not decided which Order is energetically more meaningful. But you give it away significant energy savings potential.

Frequently determine the regulations also by trial operation, to what extent currently higher temperatures are reachable.

patent DE 199 27 027 C1 Although dealing with the combination of solar systems and heat pumps, but has the disadvantage that not the most energetically sensible consumer is given priority.

In addition, will the irradiation is used as an arithmetic variable, so that a corresponding sensor necessary is. The collector data (characteristic) must be known and can be from the scheme can not be determined.

The invented control principle draws from collector temperature and heat quantity Conclusions on the amount of heat at other temperatures. This can be determined by prognosis, whether the aspired higher ones Temperatures at all are feasible. This is eliminated the usual one Trial run. Furthermore can thus determine the optimal order for the use of solar energy become.

It could be shown that through the optimized scheme the combination Heat pump / solar system energetically cheaper can be operated and thus the power consumption decreases.

The efficient combination of solar systems and heat pumps does not improve only the efficiency of each plant, but at the same time elevated also the acceptance of the builders by even lower operating costs. The share of electricity as auxiliary energy decreases and the environment becomes so relieved.

Embodiment:

By permanently registered in the control or metrologically determined by the controller itself parameters of the efficiency characteristic of the collector and the performance of the heat pump can be predicted by measuring temperatures and heat amount, which heat conditions at other temperatures can be achieved.

k, k2

übliche Kollektorkonstanten

The metrological approach for determining the efficiency characteristic is the following:
The solar generated heat quantity QS at the collector temperature TK and the outside temperature TA are measured in a start function. QS = constant × solar irradiation - k (TK - TA) - k2 (TK - TA) 2

k, k2

usual collector constants

There the solar irradiation can change and be no measurable variable should, must Determination of the start parameters in a relatively small time window done so that the solar radiation is assumed to be constant can be. For this reason, for the start function also TA assumed to be constant. This situation is governed by the scheme or checked by the user.

It At least 3 value groups are required to calculate the two coefficients k and k2 determine.

Known Coefficients of efficiency can also be used in this scheme be entered immediately by hand.

TK1

derzeitige Temperatur im Kollektor

TK2

angestrebte Temperatur im Kollektor

These starting values serve to determine the curve for the prognostic behavior. QS (at the target temperature) = QS (current heat quantity) + k (TK at current temperature - TK at target temperature) + k2 (TK1 2 -2 TA TK1 - TK2 2 +2 TA TK2)

TK1

current temperature in the collector

TK2

desired temperature in the collector

Corresponding the amount of heat accounted for After that decided whether it makes more sense, the solar heat directly to feed into the heating or water heating or at the Heat pump through a higher one Source temperature to improve the coefficient of performance.

in this connection have to also consider the technical parameters of the heat pump. Again, the user can decide the dependence of source and heating water temperature, thermal output and power consumption in a startup function itself metrologically too capture or manually known technical data on the Keyboard input.

In several calculations is the power consumption of the entire system at the various potential Feed orders determined. Subsequently, the variant with selected the lowest power consumption and set the priority for this.

By the possibility the metrological determination of the starting parameters is the regulation independently the type of collector and heat pump.

aggravating comes with heat pump heaters to add that Most are operated with special tariffs of the energy suppliers who Locking periods included, of course considered differently in the control behavior Need to become. While In the blocking period, it only makes sense to increase the solar yields to increase the source use if the other consumers have already been served.

There the source temperature increase not always meaningful (for example, drying out of the soil in the summer if the floor temperatures are too high), additional constraints can be set for this become.

As with other solar regulations, it is still possible to set priorities manually in other conditions (e.g., no hot water demand while vacation) to operate the system energetically favorable.

Of the Formalism of order optimization is in principle also usable in heating systems other than the heat pump. He can Also only be used for hot water and heating operate optimally solar yield.

Claims (2)

Control method for thermal solar systems, characterized in that on the amount of heat and collector temperature forecasts are made to the solar yield at other temperatures. These forecasts serve to optimize the feed-in sequence of solar yields for different consumers. The optimization can be done both in terms of energy consumption, as well as the economic or environmental benefits (eg changing tariff structures). Is one of these consumers the source of heat pump heating? will over the technical parameters of the heat pump dependent on of heating water and source temperature in comparative cycles the best variant (for example, those with the lowest electric energy consumption) determined. Accordingly, the priorities are then determined.