Solar thermal doesn't change result

Phildodd · Posts: 30

I'm sure this has come up before but I can't remember the answer, although I think it is a problem with SBEM. I am working on a school project and have built the model with basic heating and hot water systems. I have run the calcs to get a base BER and then added various systems to see the effect that they have.

When I add solar thermal to the hot water system serving the kitchen it doesn't make any difference to the result, I appreciate that it won't make much difference but it should improve slightly.

Has this happened to anyone else and how did you solve it?

Andrew Bairstow · Site Admin Posts: 343 Location: Birmingham, UK

The demand for hot water in a building defined by SBEM is created by the people using the spaces in the building rather than the presence and use of hot water in the spaces. Thus you need to assign the hot water system to the people/zones which benefit from the service. This is problematic where there are two systems in use: one for food preperation and one toilets though in theory, should you know the relative demand of each you could assign one bi-valent system.
If you, say, assign this hot water system to a teaching space then the difference should show up in the breakdown of energy use in the BRUKL report.
Regards
Andrew

Phildodd · Posts: 30

Thanks for the reply, I though it was something like that. It is difficult as the kitchen serves the whole school as do the toilets and how can you predict the demand for hot water in primary school toilets. Do the little darlings wash their hands afterwards?
One solution may be to allocate the toilet system to the classrooms and the kitchen system to the rest of the school and see what that looks like, or try a bi-valent system as you suggest.

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