Ventilation Rate Testing Procedure

This chapter presents a standard test procedure of a tightness test for ventilated solar thermal collectors. This is needed for calculation of the ventilation rate in collectors, which is one of the major effects that influence the microclimate in collectors, thereby influencing the loads for degradation of components in solar collectors.

The correlation between microclimate and ambient climate is described by the ventilation rate, which means the airflow rate into the collector. The driving forces for ventilation of the collector are primarily an air pressure difference between the surroundings and the air gap. The procedure was tested using a round robin format.

Four laboratories participated in the tests. The purpose of the round robin testing was to test the procedures in the standard test method for measuring the air tightness of collector boxes. In the standard test method, the procedure requires setting a ventilation rate through the collector and measuring the pressure difference between the inside and outside of the collector box.

In general the agreement among the measurements was good..