Development and Performance of a Solar-Cum-Gas Fired Dates Drver

摘要

Dates are the third most important fruit of Pakistan. It is grown on an area of about 78,000 ha, and its annual production is 625,000 tonnes. Sun drying of dates is the common practice prevailed in Pakistan. Sun dried dates have a short life and are not free from contamination and aflatoxins. Therefore, these cannot be presented in the international market for better return. About 22 % of the total dates produced in the country are wasted every year due to unavailability of proper drying/ processing, and storage facilities. To overcome these problems, a solar-cum-gas fired dates dryer was developed at the Farm Machinery Institute, National Agricultural Research Centre, Islamabad. It consisted of eight flat-plate solar collectors, a drying chamber, and an axial flow fan. A gas burning system was also developed as a supplement source of heat.rnThis dryer was installed and evaluated at Mitra Abad, Dhaki, D. I. Khan in August 2003. Experimental results indicated that the system was capable of drying/processing about 544 kg of fresh dates within 5 days. The seasonal drying capacity of the dryer was predicted at about 4 tonnes, with a value addition of Rs.rn72,116. It was a small scale on-farm dates drying technology, and was well suited to produce quality dates in order to present them into the international market.