ᐅ How do I choose the most efficient solar panels?

Hello everyone,

I want to supplement my pellet heating system with solar collectors. They should be as small as possible, meaning they need to have a high efficiency. (The issue of BAFA funding is secondary.) This most likely means using evacuated tube collectors with CPC (compound parabolic concentrators).

But how many do I need? What figures should I request from the manufacturers?

I know that under the current weather conditions (July 2018, Stuttgart area) I have to heat my 550-liter (145-gallon) buffer tank by about 30 Kelvin (from 44°C to 74°C / 111°F to 165°F) every two days. With slightly worse weather, this needs to be done daily. Ideally, I would like to avoid using the pellet burner for this.

If the daytime temperature ranges between 10°C and 20°C (50°F and 68°F), the temperature difference is 45 Kelvin (from 39°C to 84°C / 102°F to 183°F). But in that case, it’s okay if the burner heats up at night as well.

Does anyone have helpful tips for me?

Thanks and regards,
Dietmar

The heating installation company provided us with excellent advice and carried out the necessary calculations. Due to the energy saving regulations, we also had to meet certain requirements, which were calculated for us in advance by the structural engineer.

Hello niri09,
have you seen the calculations (and been able to follow them)?
Or did they just say that they had calculated it?
I respect the craftsmen's experience, but usually it's more of an estimate.
I would just like to understand and verify it with my school knowledge before I buy it.
Best regards, Dietmar

Hello Dietmar,
Yes, of course I have seen it. According to the energy saving regulations, I need to consider the project requirements. Our structural engineer then checked whether everything fits as the plumbing/heating specialist said.