The g-value measurement system follows the methodology of the “Cooled plate method” described by Tillman Kuhn in “Calorimetric determination of the solar heat gain coefficient g with steady-state laboratory measurements.
The measuring apparatus consists of a solar simulation, a climatic chamber, and a metering box. The measuring apparatus can be summarized as follows:
- Light emitted by the solar simulator passes through the transparent aperture and is then directed towards the test specimen. The light passing through the test specimen is absorbed by the cooling device.
- An airflow generator is installed in the climatic chamber in order to adjust the external surface coefficient of heat transfer.
- The absorber plate is installed opposite to the test specimen in the metering box and connected to a hydraulic circuit in order to remove the solar heat gain and the thermal transmission that enters the metering box.
- All the heat flow rates passing through the metering box are negligible.