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Zhe, TRNBuild has two concepts that are important here. An "airnode" is an area of the building that can be represented by a single air temperature. A "radiation zone" is volume within the building in which all of the walls can "see" each other. How you decide to break up the building into airnodes and radiation zones depends on what is crossing the boundaries between them. For example if you have an atrium with a glass roof or a glass wall there is going to be vertical stratification (i.e. multiple airnodes) and it is the solar radiation that is going to cross the airnode boundaries so you'll combine those airnodes into a single radiation zone. Virtual surfaces are used as boundaries between the airnodes because radiation can cross a virtual surface. In your case, I think you have a greenhouse attached to the side of a building so that there will certainly be a temperature difference between the greenhouse and the rest of the building but there probably won't be very much radiation crossing the boundary between the two. In this case there isn't any need to define a virtual surface because there isn't much radiation passing. You can define there to be a "wall" between the two airnodes when you are drawing the building in SketchUp. Then when you go to TRNBuild, you can set that wall's properties so that it has a very low thermal resistance (high u value). In this way the wall will allow you to define convection between the two airnodes and there will be little resistance to conduction heat transfer. best, David On 07/20/2015 19:17, Zhe Kong wrote:
-- *************************** David BRADLEY Principal Thermal Energy Systems Specialists, LLC 22 North Carroll Street - suite 370 Madison, WI 53703 USA P:+1.608.274.2577 F:+1.608.278.1475 d.bradley@tess-inc.com http://www.tess-inc.com http://www.trnsys.com |