Denen Bos Solar - Are they good?

macnab

A well known Builders Providers is selling Denen Bos solar DHW systems. I am haggling with them at the moment on price. They supplied most of my hardware for my new build so I am hoping to get a good quote.

But the question is: are they a good choice. The specs on the web site dont excite me but maybe I am missing something.

All help much appreciated.

PS please excuse the sloppy title, its supposed to read: Denen Bos Solar - Are they good?

Evergreen

I took a quick look at their website and your right, the data they give is not great. If you take for example the 20 tube system here is a summary of the panels dimensions and performance data.

Gross Area 3.64 m2m
Aperture Area 1.89m
Total Panel Output = 1000 kWh/a - nice round number
Output per m2 Aperture = 529 kWh/m2/a
Output per m2 of roof covered = 275 kWh/m2/a

To put these figures into persepective;

A good tube system you could expect the following results
Output per m2 Aperture = 612 kWh/m2/a
Output per m2 of roof covered = 532 kWh/m2/a

A medium flat planel system you could expect these results
Output per m2 Aperture = 520 kWh/m2/a
Output per m2 of roof covered = 477 kWh/m2/a

You can make your own mind up after that

macnab

Thanks evergreen.

PeteHeat

Hi Evergreen,

The Data is not great, But it is honest

.

quentingargan

As in other posts, Evergreen's figures favour flatplates because the figures totally ignore incidence angle modifier and use noon efficiency only. Flatplates are at their most efficient at noon (obviously) whereas vacuum flask systems are at their most efficient during the morning and afternoon. The reasons for this are complex, but are explained here.

So at a time when a flatplates is at 60% of its noon efficiency, some vaccum flask systems are working at well over 100% of their noon efficiency.

On sunny days both will provide you with plenty of hot water - where vacuum flasks excel is in extending the seasons into spring and autumn and on cloudy days. This seasonal stretch isn't shown in the figures for overall annual performance.

I have no axe to grind on this - I work with both flatplates and tubes, but we sell flatplates based on their aesthetic appeal, not their efficiency.

AckwelFoley

Denen boss solar is...

im not going to say because it would be libelous, but lets just say from my expierence its not what id choose even if ignoring the poor outputs.