“DESIGN,  FABRICATION AND EXPERIMENTAL INVESTIGATION  ON  THERMAL PERFORMANCE OF PARABOLIC SOLAR DISH  CONCENTRATOR BASED SOLAR DRYER ASSISTED WITH ROCK-BED HEAT ENERGY STORAGE” (A CASE OF MANGO SLICE DRYING)

Hailemariam, Mulugeta

dc.contributor.author	Hailemariam, Mulugeta
dc.date.accessioned	2022-02-21T11:44:15Z
dc.date.available	2022-02-21T11:44:15Z
dc.date.issued	2021-10
dc.identifier.uri	http://ir.bdu.edu.et/handle/123456789/13021
dc.description.abstract	Drying crops using solar energy is of countless economic significance all over the world, particularly in Ethiopia, where most of the crops and grain harvests are lost to fungal and microbial attacks. Due to those problems, an indirect, active type, eco-friendly, low-cost solar dryer with a Parabolic dish solar concentrator with rock-bed thermal storage material was designed to dry various agricultural products. Before the solar drying test, a preliminary investigation was done using an oven drying test in order to determine the optimum drying temperature for the mango slices and to investigate the effect of temperature on the physico-chemical value of the mango slices.Solar drying experiments were conducted to dry mango slices and to investigate drying characteristics like drying rate, quality of dried mango in terms of color,taste, rehydration ratio, and shrinkage ratio. Mango slices dried at 1 m/s air flow rate were of the best quality in terms of color, taste, and shape when compared to those dried at 0.5 m/s and 2 m/s air flow rates in the drying chamber. The dryer was designed based on the climatic conditions of Bahir Dar, Ethiopia, with an average ambient air temperature of 22 and yearly average global solar radiation incident on the horizontal surface of about 535w/m 2 and with average relative humidity of 48 . The experimental tests were carried out with load and no-load conditions. With the no load tests, the maximum amount of temperature was recorded relative to the load condition. The thickness of mango slices was selected to be 3mm compared to 6 mm and 9mm interms of drying rate and moisture removal rate, which is an appropriate size as thinner slices would lead to case hardening and reduce the drying rate, whereas thicker slices would also reduce the drying rate due to the diffusion process.During testing of mango drying its moisture content was lowered from 81.4 to 15.3 . From the test results, the average collectore thermal and drying efficiency with thermal storage was 65.5 and 16.5 and the maximum drying temperature for mango slices is 80 , from the preliminary oven investigation. Different thin-layer drying models were evaluated during the experimentation, and the page model was the best fitting model for mango slice drying using criteria of high coeficient of determination (R 2 ) close to unity and lower value of mean bias error, root mean square error, and ch-square value closed to zero.	en_US
dc.language.iso	en_US	en_US
dc.subject	ENERGY CENTER	en_US
dc.title	“DESIGN, FABRICATION AND EXPERIMENTAL INVESTIGATION ON THERMAL PERFORMANCE OF PARABOLIC SOLAR DISH CONCENTRATOR BASED SOLAR DRYER ASSISTED WITH ROCK-BED HEAT ENERGY STORAGE” (A CASE OF MANGO SLICE DRYING)	en_US
dc.type	Thesis	en_US