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Abstract: An experimental setup to investigate the thermal performance of a cylindrical cavity receiver for an SK-14 parabolic dish concentrator is presented in this technical note. The thermal performance is evaluated using energy and exergy analyses. The receiver exergy rates and efficiencies are found to be appreciably smaller than the receiver energy rates and efficiencies. The exergy factor parameter is also proposed for quantifying the thermal performance. The exergy factor is found to be high under conditions of high solar radiation and under high operating temperatures. The heat loss factor of the receiver is determined to be around 4.6W/K. An optical efficiency of around 52% for parabolic dish system is determined under high solar radiation conditions. This experimental setup can be used as teaching tool for people with little or no knowledge about solar dish concentrators due its simplicity and the basic mathematical formulations applied. Different types of receivers and different types of deep focal region parabolic dishes can also be tested with the experimental setup. [Copyright &y& Elsevier]

This paper is concerned with thermodynamic analysis of the process of single-layer drying of apple slices by means of a cyclone-type dryer. Using the first law of thermodynamics, energy analysis was performed to estimate the ratios of energy utilization throughout the drying process. Exergy analysis was carried out to determine exergy losses during the drying process by applying the second law of thermodynamics. It was concluded that the exergy losses increased with increasing energy utilization in both trays and the drying chamber. Values of the energy utilization ratio (EUR) of the drying chamber varied in the range 0–41.64 per cent depending on the drying conditions. The most exergy losses took place on the first tray (EUR = 0–21.06 per cent) during the drying of apple slices. It is emphasized that apple slices are sufficiently dried in the range 60–80 °C with 20–10 per cent relative humidity and a drying air velocity of 1.5 m/s over a 3.33–5.33 h period in spite of exergy losses of 0–1.243 kJ/s (EUR = 0–34.72 per cent). [ABSTRACT FROM AUTHOR]