Solar drying of sweet pepper and garlic using the tunnel greenhouse drier

MIGUEL CONDORI; RICARDO ECHAZU; LUIS SARAVIA

RENEWABLE ENERGY

Elsevier Science

Lugar: Great Britain; Año: 2001 vol. 22 p. 447 - 460

0960-1481

A new low cost design for a forced convection greenhouse drier, the Tunnel GreenhouseDrier, has been built and tested. Its main parts are: a plastic greenhouse cover containing adrying tunnel made with transparent plastic walls; a line of carts with several stacked trayscontaining the product and moved manually inside the tunnel and an electrical fan that movesthe hot air from the greenhouse into the tunnel. The trays receive solar radiation through thetransparent walls, increasing the product temperature. Heat losses from the tunnel are lowsince greenhouse temperatures are higher than ambient temperature. The main advantages ofthis drier are: (a) an almost continuous production since some carts with dried product comeout of the tunnel every day, while the same amount of fresh product is introduced by the othertunnel extreme; (b) lower labor cost since the product handling is partly mechanized; (c) aconventional heater can be easily installed to keep a constant production rate; (d) the energyconsumption is lower than in other drier types; (e) the installation can be used as a greenhousefor small production when it is not used as a drier. The prototype was built in the North ofArgentina, and red sweet pepper and garlic were used as load. The drier thermal efficiency,considered as a solar collector, was calculated using the measured experimental data, and alinear relation between the drier temperature and the solar radiation was obtained.