RE: Ground temperature

[Michaël Kummert <kummert@xxxxxxxxxxxxx>]

Dear Helmi,
You said you set HBack to 0.002. This is very different from 0.001 for
Prebid. 
All values <= 0.001 have a special meaning for boundary walls: they are
interpreted as "direct contact". So 0.001 (or lower) is actually a "special
instruction" which means "direct contact" (i.e. infinite value of HBack),
while 0.002 just means "0.002".

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 helmi
Sent: Tuesday, June 03, 2003 03:21
To: trnsys@relay.doit.wisc.edu
Subject: RE: Ground temperature


Dear Michaël
Yes, it.s very surprising, but isn.t the same as if we take Hback=0.001,
this will set the  Boundary temperature directly to the outside surface
temperature? (see the answer of the Trnsys hotline team)
I thought to another idea: take a very high value of Hback and set the
ground temperature as the internal surface temperature of the floor (an
output of type 56), but this gives the roughly the same results.
The problem of the ground temperature is quite complicated.
Best regards


Ing. Helmi Ben Rejeb
Ecole Nationale d'Ingénieurs de Tunis, BP 37, Le belvédère, 1002 Tunis,
Tunisia.




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