1.2. Previous test procedures

All different sensors to register the climatic and operational parameters should be calibrated and installed. The collector would be mounted according to the manufacturer’s installation instructions.

The whole recirculation system must be verified in test conditions; the temperature of supply water to the collector from the storage tank must be keep in a stable level; and the automatic acquisition data system must be installed and tested.

1.3. Test

The test is firstly carried out in steady-state conditions according to ISO 9806. The collector will be tested over its operating temperature range under clear sky conditions in order to determine its efficiency characteristic. Data points will be obtained for at least four water inlet temperatures spaced evenly over the operating temperature range of the collector. Especially, one inlet temperature shall be selected such that the mean temperature in the collector lies within ± 3K of the ambient air temperature, in order to obtain an accurate determination of n0. At least four independent data points

shall be obtained for each inlet temperature, to give a total of 16 data points. After this, in order to evaluate the thermal performance of solar collectors during the actual operation, solar collectors will be continuously tested during the day to obtain the characterization under different weather and working conditions.