TYPE 45

[jsalazar@xxxxxxxxxxxxxxxx]

Dear TRNSYS Users,

Currently I am working on my master?s thesis, which investigates the impact of
compact solar domestic hot water systems on electricity peak reduction and total
energy consumption. A group of 60 low-income families in Brazil is participating
in this project. Although several validation papers of TYPE 45 are available in
the literature, we also will be doing validation of TYPE 45 for our compact
solar system (integrated horizontal storage tank). As part of this validation
procedure, I have done extensive literary review on the papers that originated
TYPE 45, primarily those of G. L. Morrison. Today I started to read the TRNSYS
TYPE 45 source code and found a possible error in the calculation of the
effective incidence angle for diffuse radiation.

EFFSKY=59.98-0.1388*SLOPE+0.001497*SLOPE*SLOPE

The correct formula, according to the original paper from which this formula was
taken (Brandmuehl, M.J. Beckman W.A. Transmission of diffuse radiation through
CPC and flat plate collector glazings. Solar Energy 24 pp. 511-513) is:

EFFSKY=59.68-0.1388*SLOPE+0.001497*SLOPE*SLOPE

I honestly don?t think that 0.3° in the final simulation results makes much of a
difference but if this formula does indeed have a mistake, it should be
corrected in future releases.

Best regards,
Juan Pablo de L. C. Salazar




----------------------------------------------------------------
LABSOLAR/NCTS - EMC - UFSC