Re: [TRNSYS-users] Solar collector array

[Jeff Thornton <thornton@tess-inc.com>]

If you keep the same flow rate through each collector (as you have done in the 3-cases you listed), putting collectors in series will cause the outlet temperature from the array to rise which will reduce the efficiency of the collectors.  In simple terms, the second collector sees an increased inlet temperature and therefore lower efficiency than the first, the third sees an even higher inlet temperature etc.

Jeff Thornton
TESS

Sent from my iPhone

> On May 13, 2014, at 7:35 AM, Martin Berov <martber88@gmail.com> wrote:
> 
> Hi,
> 
> I'm simulating solar assisted heating with underfloor heating (set temp. 40C). I want to investigate the influence of solar collector connections in the array (number of parallel and serial) in regard of solar fraction.
> When I compare for example 32m2 with 4 in serial (flow rate 800 kg/h) I get lower solar fraction compared with 32 m2 with 2 in serial (flow rate 1600 kg/h), even I get that the maximum solar fraction I can achieve if all 32 m2 (flow 3200 kg/h) are connected in parallel.
> Only if I increase the flow rate at the serial connection then I get bigger solar fraction.
> I use solar collector Type 539 and tank Type 60 with internal heat exchanger
> 
> Does have someone experience(explanation) regarding this kind of issue?   
> 
> Kind regards
> Martin
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