[Bldg-sim] "Qualified" energy modeling tools for LEED NC v2.2

Timothy McDowell mcdowell at tess-inc.com
Fri Aug 1 07:35:40 PDT 2008

Chaoqin -

There is not a CAD interface for Type56.  TRNBuild is a program that
allows you to define your zones and enter the wall and window areas and
define orientations and adjacencies of the walls, along with defining your
internal gains, infiltration flows, ventialtions flows, etc.



Timothy McDowell
Executive Vice President
Thermal Energy System Specialists, LLC
2916 Marketplace Dr, Suite 104
Madison, WI 53719
Phone: 608-274-2577
Fax: 608-278-1475

----- Original Message -----
From: "Zhai Chaoqin" <crithy at gmail.com>
Sent: Fri, August 1, 2008 9:04
Subject: Re: [Bldg-sim] "Qualified" energy modeling tools for LEED NC v2.2


I am not familiar with TRNBuild. Does it have a built-in CAD interface
that one can draw a building? Can one define building surfaces by
coordinates? Can one import a 2-D or 3-D CAD drawing? As I recall in
Type56, one needs to pre-calculate the wall and window areas by
orientation for each zone and input the area value into TRNSYS. I am not
sure if this is still the case.


On Fri, Aug 1, 2008 at 9:43 AM, David Bradley <bradley at tess-inc.com> wrote:

 There are three parts to the geometry issue.

 For internal radiation exchange, you are correct that TRNSYS is a
non-geometrical model and that two surfaces do not have any knowledge of
their mutual view factor. Like many of the other building models out
there, TRNSYS uses a star-network in which each surface "radiates" to
the air node and vice versa.

 For external geometry, one defines orientations in the building
processor (TRNBuild) and then defines corresponding surfaces (slope and
azimuth) in the weather data reader. Solar radiation from a particular
weather data reader surface is then linked to the appropriate Type56
inputs for each orientation defined in TRNBuild.

 For external shading (including building self-shading), one places a
series of wingwall and overhang components between the unshaded solar
radiation calculated by the weather data reader and the building, in
effect cutting down on the amount of radiation incident on the building.
It is a flexible methodology but a bit of a cumbersome one. One of the
main pushes in the current development of TRNSYS 17 is a much more
automated methodology for doing building self-shading. The Type56
developers are also working on a true view-factor methodology for
internal radiation exchange within a zone.

Kind regards,

David BRADLEY - Principal

Thermal Energy System Specialists, LLC
2916 Marketplace Drive - suite 104
Madison, WI  53719

Ph: +1.608.274.2577
Fx: +1.608.278.1475
bradley at tess-inc.com

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