Construction and evaluation of rotary solar dryer for fish drying

Rotary solar dryer was developed and evaluated for fish drying. People preferred dried prawns in diet in off seasons. Dried prawns are in high demand in the market and hence Prawns (Kolambi) were selected as drying material. Time required for reducing the moisture content from 75 per cent to final moisture content 16 per cent for sun drying werecompared with solar drying. Evaluation parameters were collection efficiency, system drying efficiency, pick-up efficiency, moisture ratio and drying rate. Maximum temperature observed inside the dryer at 13 pm was 57 0C whereas maximum ambient temperature observed was 35.30C at 12:54 pm and solar irradiation was 600 W/m2 at 11:14am. It was observed in total five slots of trays, averagedrying efficiency for salted fish was 14 per cent and unsalted fish was 11 per cent. Inside the drying chamber, increasing profile temperature was observed from bottom tray to upper ray. Humidity inside dryer was minimum as compared to outside condition. Overall collection efficiency was found as 70.97 %. Salted fish inside the dryer required 8 hours to dryprawn’s up to 16.15 per cent while unsalted fish required 15 hours to reach moisture content up to 15.15 per cent in open condition. Unsalted fish inside the dryer took slightly higher time to reach up to moisture content 16.91 per cent whereas salted in open condition required 13 hours to dry up to 16.37 per cent