Thanks for your explanation. But my
real concern is whether Type 31/709 is suitable as a model for heating
pipes in a greenhouse, since I do not have Type 604.
Kind regards, Knut Erik
David Bradley <bradley@tess-inc.com>
05/14/2009 08:05 PM
To
knut.erik.enerstvedt@niva.no
cc
thornton@tess-inc.com, trnsys-users@engr.wisc.edu
Subject
Re: [TRNSYS-users] Heating pipes model
Knut Erik, Type31 and 709 take an overall UA for losses from the pipe. Where Type604
goes a bit farther is to calculate the loss coefficient based on some natural
convection correlations. I think it also separates out convection and radiation
and accounts for the thermal mass of the pipe and insulation. Kind regards, David
However, I can't seem to find Type 604 in the TESS Hydronics library. Instead,
I see that Type 604 is listed among the individual TESS components. Do
you think it would be possible to use Type 31 or Type 709 (TESS Hydronics)
instead, connecting the "environment losses" output as GAIN in
Type 56, or is this a bad idea since I can not separate conective and radiative
gains?
<I need to model heating pipes commonly found in greenhouses. The pipes are in loops located 15 cm above the floor, 1 m above the floor, along
the walls and somewhat below the ceiling. Hot water flows in the pipes and heats up the greenhouse. I use Type 56 to model the greenhouse, but have not yet succeded in finding a model for the heating pipes. Does anyone know an appropriate model for the heating pipes and how to use it in combination with Type 56? >
We use the Type 604 model (TESS Hydronics) which accounts for the convective and radiative heat transfer to the zone. Then simply set
up a new "gain" inside of Type 56 and set the radiative and convective
gains as inputs to Type 56. Then make the connections from Type 56 to the
pipe (zone temperature and effective surface temperature) and from the pipe
to Type 56 (radiative heat transfer and convective heat transfer).
Jeff
Jeff Thornton President - TESS, LLC
22 North Carroll Street - Suite 370 Madison WI 53703 USA
-- *********************************************************************** Thermal Energy System Specialists (TESS), LLC David BRADLEY
22 N. Carroll Street - Suite 370 Partner
Madison, WI 53703
USA P: +1.608.274.2577 F: +1.608.278.1475 E-mail: bradley@tess-inc.com Web Pages: http://www.tess-inc.com and http://www.trnsys.com
*********************************************************************** ------------------------------------------------------------------------------------------------------------
Meld deg på vårt nyhetsbrev på www.niva.no