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Re: [TRNSYS-users] TRNBUILD Type 56 crawl spaces



Franck,
  Crawlspaces are usually accounted for in one of two ways.

The simplest way is to define a zone for the crawlspace and to make the floor in the zone above into an "ADJACENT" type wall. Energy transfer through the walls of the crawlspace is then calculated by defining BOUNDARY walls that contain whatever material forms the walls and floor of the crawlspace (usually concrete) and an effective, massless equivalent insulation to account for the soil. The temperature on the back side of the BOUNDARY walls is usually calculated using the Kasuda ground temperature correlation (Type77).

The more complex (but arguably more correct) approach is to use a ground coupling component such as the ones in the TESS Ground Coupling Library. These components define a volume of soil surrounding the crawlspace on its four sides and bottom, breaking the volume up into finite elements called nodes. At each TRNSYS iteration, the models take the Type56 calculated surface temperature of the walls and floor of the crawlspace zone as inputs. They perform a 3 dimensional finite element energy balance on the nodes in the near-field and return the temperature of the crawlspace wall/soil boundary to Type56. The near-field is surrounded by a far-field that acts as an infinite energy source / sink. Far field soil temperature are governed by depth and time of year.
Kind regards,
 David


At 09:08 7/3/2006, franck clottes wrote:
Hi,

How to take into account floors with crawl spaces in trnbuild?

Best regards,

F.C.
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