The tests began placing in the front wooden frame of the first module the clear glass, in the frame of the second one the filter glass, and on the third one the reflective glass. Eight type-T thermocouples were placed in the small scale test cell; two of them to measure the interior temperature, T, the temperature difference between the interior and exterior of the test roof, ATl, and the temperature difference between the interior and exterior of the glazing, ATv. Additionally, two thermocouples were placed to measure the ambient temperature, Ta. An acquisition system PCL-812G were used to record and process all the temperatures measured. To register the electricity consumption by the air conditioning systems, three sensors multifunction, form 2S, class 200 with integration time of 1 minute measured the amount of electricity consumed. These sensors storaged the measurements and at the end of each test, an optical cable was connected between the sensor and the acquisition system. The incident solar radiation impinging on window and on the roof was measured by using two Eppley pyranometers: a black and white pyranometer and a spectral precision pyranometer. Figure 3 shows the experimental set up during the testing. The wind velocity was measured with an ALNOR thermoanemometer.

The experimental test were performed at the city of Cuernavaca, Mbrelos, Mexico of 18.5o North latitude and 99 o longitude. The procedure was as follow: The three modules were placed outdoors facing south by 10 hours on July 7th, 2000. Temperature measurements were averaged each 30 seconds; solar radiation and wind velocity were measured and averaged every 10 minutes.