Initial experimental tests on the use of small passive-solar test-boxes to model the thermal performance of passively solar-heated building designs

Small passive-solar test-boxes can be a useful tool in the thermal-modelling of a passively solar-heated building designs. Several cubic-meter sized test-boxes have been constructed that incorporate basic elements of passive-solar design: glazings to admit solar radiation, good thermal insulation, and large thermal storage capacity within the insulation-envelope. The experimental thermal behavior of these text-boxes has been accurately computer simulated using weather and solar radiation data inputs, and correlated with the performance of large passive test rooms nearby. Similar small test boxes can be constructed to perform as thermal models of a particular passive-solar building design, by normalizing the appropriate thermal design parameters to one critical parameter, such as south-facting glazing area, or building floor area. Thus a thermal model will not resemble a scaled architectural model of the building, but will be distorted in appearance so as to exhibit thermal behavior similar to the real building. For a particular passive-solar building design to be located at a given site, a small thermal model of the building can be constructed and placed at the site to investigate possible micro-climate effects, such as a south-facing slope or nearby trees. The use of small passive-solar test-boxes complements simulation analyses of the influence of macro-climate and geometry on the performance of passive solar heated buildings. The accuracy and limitations of using small test-boxes to predict passive-solar building performance are discussed.