Re: TYPE 45

[Michaël Kummert <kummert@xxxxxxxxxxxxx>]

Juan,

> ...
> 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.

Thank you for letting us know. You are right, this seems to be a typo in 
Type45 source code. The manual and the source code for Type 1 have the 
correct value (59.68). It's not a too bad error, but we will fix that in 
the next release.

Kind regards,

Michaël Kummert


--
_________________________________________________________

Michaël Kummert

Solar Energy Laboratory - University of Wisconsin-Madison
1303 Engr Res Bldg, 1500 Engineering Drive
Madison, WI 53706

Tel: +1 (608) 263-1589
Fax: +1 (608) 262-8464
E-mail: kummert@xxxxxxxxxxxxx

SEL Web Site: http://sel.me.wisc.edu
TRNSYS Web Site: http://sel.me.wisc.edu/trnsys