Experimentation of the Solar Dryer With ParabolicTrough: Drying of Okra

According to Arthur S. EDDINGTON (1921):“I can prove nothing to you whether you do notlet me make any measurements. Measurementis for me the only way to find the laws of nature.I’m not a metaphysicist.”In order to confirm the performances of theindirect solar dryer, with Parabolic TroughCollector (PTC). It consists of two essentiallinked parts: the drying chamber and thereflective concentrator block and the coaxialtubular receiver is housed. The latter is wrappedin transparent pieces of glass, opaque toinfrared. This envelope limits the enormousradiative and convective losses. Thegreenhouse, trapping in addition to directradiation, will be responsible for the increase inthe air temperature, both in the receiver andinside the drying enclosure, thus promotion itsnatural flow.The performances noted by the numericalresults and validated by the value of the Rootmean Square Error, RMSE, equal to 4.5°C,between the numerical and experimentaltemperatures of the heat transfer fluid, at theentrance of the drying chamber, experimentaltests of the said dryer were carried out, via thedrying of the variety, Clemson spineless, ofokra. The diffusion coefficient of dried okrapieces gave satisfactory results, (16.49-22.72)×10^-10m².s^-1 for cylindrical samples and (6.24-15.59)×10^-10m².s^-1 for longitudinal slices. These findings are consistent with the literature.