[TRNSYS-users] about solar fraction

David BRADLEY d.bradley at tess-inc.com
Mon Nov 25 13:10:57 PST 2019


Emre,

  The most correct way to calculate the solar fraction is to sum up all 
of the energy consumed by the system (fans, pumps, auxiliary heaters) 
for each month and then to run the system again with the solar part of 
it disabled (or you can run a non-solar comparison system in parallel) 
and again sum up the energy consumed by all the equipment and divide the 
two by one another. The trouble with the method that you propose is that 
it may not be that all of the energy gain from the collector can be 
applied against the heating load. You have losses from storage, 
parasitic power from pumping, and it may be that the useful solar gain 
is only available when your load is already satisfied.

kind regards,

  David


On 11/25/2019 14:00, Emre Arpaci via TRNSYS-users wrote:
> hi trnsys users
> I have a question about solar fraction I m heating a space with solar 
> assisted heat pump. and I want to calculate solar fraction with 
> trnsys. I m using fan coils to heat up the space. so how can ı 
> calculate solar fraction.If I do that the useful energy gain of 
> collector in montly divided by required heating load in montly.
> is it give me the montly solar fraction or am i wrong ?  ( I dont have 
> dhw in my system)
>
>
> regards
>
> _______________________________________________
> TRNSYS-users mailing list
> TRNSYS-users at lists.onebuilding.org
> http://lists.onebuilding.org/listinfo.cgi/trnsys-users-onebuilding.org

-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
3 North Pinckney Street - suite 202
Madison, WI  53703 USA

P:+1.608.274.2577
F:+1.608.278.1475
d.bradley at tess-inc.com

http://www.tess-inc.com
http://www.trnsys.com

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