April 15, 2009


The effects of solar heating potential and nocturnal cooling potential are simulated in a controlled indoor environment and extensive measurements are made along and between the boundary surfaces. Air delivered to the test section is controlled to close tolerances in temperature, humidity and flow rate. Steady state conditions, step changes, functional changes or real weather conditions can be simulated. Accurate measurements are taken at the inlet and outlet of the test section to determine the amount of heat and mass transfer across the system. The facility is completely computer controlled. The control software, employing a self-tuning proportional integral control methodology, was developed in house. A description of both the DESRAD concept and the Diurnal Test Facility is presented here along with examples of the model verification data and a brief measurement uncertainty analysis.