Energy, exergy, economic and environmental (4E) assessments of a tea withering trough coupled with a solar air heater having an absorber plate with Al-can protrusions

Abstract

Green tea leaves are dried partially at low temperatures (withered) after harvest. The present study evaluated the energy, exergy, economic and environmental aspects of a solar energy based laboratory-scaled tea withering trough. The trough was coupled with a solar air heater having an absorber plate protruded with waste Al-cans. The temperature within the trough was maintained around 35 °C. The airflow rates considered were 0.03, 0.04 and 0.05 kg/s. The maximum thermal efficiencies computed for the SAH for these mass flow rates were 52.58% at solar radiation of 747 W/m2, 63.65% at 760 W/m2 and 59.25% at 753 W/m2. The exergy efficiencies of the SAH and the withering trough were obtained within (1.41–3.56)%, (1.59–4.51)%, (1.33–4.24)%, and (32.36–72.69)%, (50.59–91.16)%, (37.50–85.62)% respectively. The economic and energy payback periods of the withering trough were computed as 0.90 and 1.26 years. The carbon credit earned was estimated within (145.25–581)$ for a lifetime of 20 years.