Installation beginner heating and solar hot water

[Dudule]

Hello,

I am new to thermal solar and I plan to install 17m2 of solar panels that I can have not too expensive for heating and hot water. This will allow me to recover more heat in winter compared to 2 to 5m2 of panels.

The thermal panels serve as a cap to protect the summer 3 bay windows facing south and I can not put an air water system since the thermal panels are not in a low point, in addition it makes noise.
The pipes go up to the roof, then to the ridge and down and back into the garage until the balloons.
In summer I plan to cover part of the panels to avoid overheating.
So I think I should use glycol.

What do you advise me to avoid overheating if this happens?
This is the case of very beautiful sunny days in spring, house inhabited only on WE, a malfunction in the installation ...
I don't have a pool or well and I don't know what to heat.

Goods.