Effectiveness and performance of double-skin airflow facades

Abstract

Double-skin airflow facades have been in use for several years in European countries. They have yet to be used in the United States. One factor is that there is a lack of a heat transfer model which can accurately predict facade performance. A model of performance has been developed by Daniel Arons. The goal of the work presented is to verify the model with experimentation on a small-scale facade. Sunlight was simulated with a 400 W metal halide High Intensity Discharge lamp. Outdoor summer conditions were simulated with a residential space heater. Two 1/8" thick panes of uncoated window glass, separated by 7", with 1" white aluminum blinds in the center, made up the facade structure. Air was driven through the channel at velocities up to 0.7 mis. The results of experimentation validate the model when no light is being projected on the facade. More work needs to be done to refine the model for cases where there is little or no airflow and also when light is shining on the facade. More specifically, the interaction between incident radiation and blinds should be refined. The greatest discrepancy between model and experiment occurs for the surface temperature of glass on the heated side.