UTILIZATION OF SOLAR ENERGY FOR DRYING SUGAR BEET TOPS | ||||
| Journal of Soil Sciences and Agricultural Engineering | ||||
| Article 4, Volume 1, Issue 7, July 2010, Page 681-697 PDF (939.11 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jssae.2010.75152 | ||||
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| Authors | ||||
| M. E. Abu-Habaga1; M. M. El-Kholy2; R. Z. Emara2 | ||||
| 1Agric. Eng. Dept., Fac. Agric., Mansoura Univ. | ||||
| 2Agric. Eng. Res. Inst., A. R. C, Giza, P.O. 256, Egypt | ||||
| Abstract | ||||
| A study was carried out to test and evaluate a green house type solar dryer for drying sugar beet tops under three different levels of air velocity (0.4, 0.8, and 1.2 m/sec), three different lengths of beet tops (3, 6, 9 cm) and two different treating conditions (with crushing, and without crushing). The changes in sugar beet tops moisture content was monitored versus the drying time until reaching the proper moisture content of about (12-13 % w.b.). Solar radiation flux incident, bulk temperature of tops, air temperature and relative humidity, overall thermal efficiency of the dryer and the protein content of the dried tops were determined. The results showed that, the hourly average available solar radiations ranged from 598.26 to 663.85 W/m2 during the experimental work. Also, the solar collector of the dryer could increase the air temperature by about 12.6, 12.31 and 12.81oC and decrease the air relative humidity by about 26.06, 23.67 and 20.97 % for air velocity of 0.4, 0.8, and 1.2 m/sec respectively. The reduction rate in moisture content of sugar beet tops was varied and increased with the increase of drying air velocity, decrease of chopping length and for the crushed samples in comparison with the not crushed samples. Also, the constant drying rate period was not detected for all studied levels of drying air velocity, while all the drying process occurred during the falling rate-drying period. The result also show that the use of the green-house type solar dryer with chopping and crushing of the green tops could decrease the drying time of sugar beet tops by about 47 to 59 h in comparison with the traditional drying method which has been taken about 78 hours. The thermal efficiency of the dryer ranged from 34.12 to 22.96 % and the protein content of the dried tops ranged from 12.57 to 14.52 % on DM basis. | ||||
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