Solar systems in winter

Hello,

..Why is only part of the flat roof covered with collectors, is the area of the solar collectors sufficient (rule of thumb 1 sqm collector area for 10 sqm living space) to optimally support, for example, the gas condensing boiler? It would be much better to cover the entire roof -> uniform appearance + energy gain.

It is now sufficiently known that solar thermal systems have not proven to be particularly economical in many cases of private use! This does not make gas usage significantly more advantageous ;) The nonsense of equipping an entire roof with a solar thermal system does not really make gas more interesting! :D

... If the modules are roof-integrated, you also save the costs of the classic roofing!

When considering cooling loads in summer, this statement is probably mistaken!
The one-sided primary energy consideration of the energy saving ordinance with regard to heating operation leads to increasing cooling loads (room temperatures) during the summer heat period. Unfortunately, the gas heat generator offers no option for this!
Conclusion: Gas only becomes interesting when active or passive cooling during the summer heat period is negligible! ;)

best regards

Thank you for your answers.
Everything very interesting.
Best regards
Frank

@ €uro:
Of course, solar thermal systems are not economical in every case; it always depends on the individual situation. The questioner had already decided on it, whether economical or not, and only wanted to learn something about snow removal. The tip was therefore to consider covering the entire roof, thus saving investment costs and improving the appearance of the property. The reference to the gas heating system was merely an example – as is also stated in my contribution. I did not write: if you put enough solar on the roof, every heating system will be profitable. Because every heating system must fit the corresponding house (in existing buildings, as you surely know, gas is still usually the only sensible heating method).
The reference to cooling loads is not really meaningful in this context, as they are completely independent of the heating system! Cooling loads depend on the construction of the house and user behavior! By using insulation materials that enable phase shift (meaning the time from solar impact until penetration into the living space is prolonged), such as wood-based materials or cellulose, temperatures are reduced and possible cooling loads do not arise. –> Keyword: Sustainable building
By the way, it is now also possible to cool via the solar system, using an adsorption chiller.

...

The reference to cooling loads is not really meaningful in this context, as they are completely independent of the heating system!

There are systems that can both heat and cool ;)

reduce the temperatures and prevent possible cooling loads from arising. –> Keyword: Sustainable building

How many cooling loads have you already calculated for newer Energy Saving Ordinance buildings to come to such a statement? The opposite is true, cooling loads are increasing!

best regards