[TRNSYS-users] Cpc - type 74_ variation of acceptance angle

Aditi Garg aditigarg107 at gmail.com
Sun Sep 29 23:44:37 PDT 2019

Dear all

I am working with type 74 (cpc-solar collector). I am using it in a small
circuit for water heating purpose. I had tried to vary the half acceptance
angle parameter for cpc (30-65 degrees). Theoretically, with an increase in
half acceptance angle value, the geometrical concentration ratio (GCR) will
decrease and related by correlation, GCR=1/SIN (half acceptance angle).

Now, the results indicate that with an increase in half-acceptance angle,
the collector outlet temperature is increasing. However, it also means that
with decreasing GCR, the temperature is increasing. This contradicts the
theoretical fact that temperature increase with an increase in GCR.

Besides, in the mathematical reference given in volume-4, page 552, the
correlation for useful heat gain, the overall heat loss coefficient (UL) is
also not divided by GCR. Generally, in concentrating collectors, the heat
losses are divided by GCR.

Any help regarding this doubt will be appreciated.

Best regards
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