A full 34 factorial experimental design for efficiency optimization of an unglazed transpired solar collector prototype

The goal of this study was to model and optimize the thermal performance of an unglazed transpired solar collector (UTC) prototype using a full factorial experiment with four factors (hole diameter, absorber coating, irradiation and mass flow rate) at three levels. A quadratic polynomial model for efficiency was shown to explain 95.47% of the variance of thermal output. Residuals analysis and analysis of variance were used to validate the best-fit model. Finally, the model was optimized using response surface representations. An optimal combination of levels of the four parameters was obtained to provide a collector efficiency of 70–80%. The chosen experimental methodology provided accurate characterization of the parameters that have the greatest impact on UTC performance.

► Design experiment methodology is applied to an unglazed transpired solar collector. ► Coating and flow rate are the most significant factors affecting the efficiency. ► Hole diameter is not statistically significant. ► Response surface graph shows the optimal efficiency ranges between 70% and 80%.