Experimental investigation of an active direct and indirect solar dryer with sensible heat storage for camel meat drying in Saharan environment

摘要

An indirect and direct forced convection solar dryer integrated with pebble sensible heat storage medium was developed and investigated under Saharan prevailing weather conditions. The setup consists of a direct chamber superimposed to an indirect drying one. A first pebble bed is placed in a plenum, below the direct drying chamber, a second in a cavity below the solar collector. The sensible heat storage system maintained the thermal efficiency of the solar collector until one hour after sunset and enhanced it by 28%. The thermal efficiency of the direct chamber was enhanced by 11.8%. Experiments of drying camel meat without salting were carried out under the different climatic conditions of July and November months. The drying kinetic evolution was investigated under each experiment conditions. The drying is faster in July than in November. Several mathematical models were tested to describe the best, in terms of statistical parameters, the drying behavior of camel meat slices. Logarithmic model and Midilli-Kucruk model are respectively the most suitable for July and November experiments. The average of indirect drying efficiency over diurnal period reached 18.34% in July and 15.52% in November. The direct drying efficiency reached the average of 10.35% and 7.88% respectively in July and November. In order to preserve the protein rate of the dried camel meat, salting which inhibits decay, pretreatment usually reserved for meat products before drying has been suppressed. Microbiological and physicochemical monitoring has been carried out to ensure the final quality of the dried product. The results obtained, compared to an open sun-dried samples were satisfactory according to the norms imposed by the Algerian legislation.