Description

The flow of air through the porous media that is used asbuilding insulation has the potential to recover energynormally lost through the building envelope via conduction. Inessence, the walls of a building can be used as a crude heatexchanger, the effectiveness of which depends on the flowdirection, flow rate, and material thermal properties. In theory,the largest effects will be seen in the situation where the airflowis counter to the conduction loss and is distributed uniformlyover the entire envelope surface. In theory, this form of distributedheat exchanger, at the appropriate flow rate, should becapable of recovering all of the energy that crosses the innergypsum board boundary.

To examine the potential for energy recovery, a researchproject, supported by ASHRAE, was undertaken in two parallelstudies: laboratory work with carefully constructed wallsections and field studies with a well-instrumented test building.This paper presents the results of the laboratory studiesand shows that the energy recovery potential is strongly dependenton airflow rate, crack geometry, and flow direction. Thework indicated that air flowing through insulated cavitiescould result in significant changes in the apparent thermalresistance of the wall sections.

Citation: ASHRAE Trans., vol. 112, pt. 2, paper no. QC-06-057 (RP-1169), p. 609-621

Product Details

Published:

2006

Number of Pages:

13

File Size:

1 file , 2.6 MB

Product Code(s):

D-28780