Re: Surface Azimuth Angle

["Laurent Serres" <laurent.serres@xxxxxxxxxxxxxxx>]

Dear Michaël,
 
if you click "more" for the input "azimuth of surface" in iisibat you obtain: 
 
"The solar azimuth angle is the angle between the local meridian and
the projection of the line of sight of the sun onto the horizontal
plane.
 
0  = Facing equater
90 = Facing west
180 = Facing north
270 = Facing east
 
Refer to the abstract for deatils on the azimuth "
 
If I understand your message "180 = Facing north" is a mistake if the project is situated in southern hemisphere ??
 
Best regards.


----- Original Message ----- 
From: Michaël Kummert 
To: trnsys@relay.doit.wisc.edu 
Sent: Thursday, April 03, 2003 12:17 AM
Subject: RE: Surface Azimuth Angle

Dear Juan,

A North-facing collector in the Southern hemisphere (as in your case) faces
the equator, hence it should have an azimuth angle of 0 in Type16 - Type1. 

The confusing part is that a South-facing collector in the Northern
hemisphere also has a 0 azimuth angle. So "0" means "facing the equator",
and NOT "North" (neither "South").

This is what the manual means by "Zero solar azimuth is facing the equator,
west is positive, while east is negative" (p. 4.9.1-5).

A few examples:
Surf. Facing due South in Northern hemisphere:     0
Surf. Facing North-East in Northern hemisphere: -135
Surf. Facing South-West in Northern hemisphere:  +45
Surf. Facing due North in Southern hemisphere:     0
Surf. Facing North-East in Southern hemisphere:  -45
Surf. Facing South-West in Southern hemisphere: +135

I hope this helps,

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@engr.wisc.edu

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



-----Original Message-----
From: owner-trnsys@relay.doit.wisc.edu
[mailto:owner-trnsys@relay.doit.wisc.edu] On Behalf Of Juan Pablo Salazar
Sent: Wednesday, April 02, 2003 15:42
To: trnsys@relay.doit.wisc.edu
Subject: Surface Azimuth Angle


Dear TRNSYS Users,
 
I have some doubt regarding the surface azimuth angle to be used when
simulating for negative latitudes (southern hemisphere). Suppose I want to
simulate a collector facing the equator in Rio de Janeiro, Brazil. According
to the angle convention in "Solar Engineering of Thermal Processes" I should
use a surface azimuth angle of 180°, right? I'm asking because the reference
manual doesn't treat this matter explicitly, referring to surfaces facing
the equator having a "zero" azimuth angle. This might cause some
misinterpretation.
 
Best regards,
Juan Pablo de L. C. Salazar