Performance Investigation of Solar Thermal Local Areke Production System Using Dish Concentrator

Abstract

Energy is indispensable for human development that strategies for reducing poverty, achieving an improved standard of living and civilization. Using solar energy for Areke production system is a quick acting solution to overcome the energy scarcity and an effective mitigation mechanism for concerning global climate changes, deforestations, and economic problems of Ethiopian’s who base their life on Areke production. The main aim of this study is to design, develop and experimentally test the performance of solar thermal local Areke distillation process using indirect heating system under Debre Birhan weather condition as an alternate source of energy instead of burning biomass. An average solar radiation is calculated as maximum in Jan (7.2 kWh/m2/day) and minimum in July (4.6 kWh/m2/day) and Annual average daily solar radiation is 6.1 kWh/m2/day. Based on minimum solar intensity, parabolic dish solar collector system with aperture diameter of 2 m, depth of 0.25 m and focal length of 1m, receiver diameter 0.15 m, length 0.27 m having truncated cone shape at the bottom side is designed in full scale. However, for the experimental test ratio of 2.22:1 is used. During absorber temperature testing improved truncated one cavity absorber has attained a maximum surface temperature of 300.3 ℃ in morning (9:45am – 12:25pm) and the thermal efficiency of the collector is obtained as 54.6% with low solar intensity. The input power required for solar thermal areke production is 0.211 kW, but input power required for traditional areke production for equal amount of input Difdif is 1.93 kW. Water started to evaporate at 90.2 ℃, ethanol evaporates at 71.4℃ this indicated boiling point is affected by altitude, if altitude increase boiling point temperature decrease. From 2 liters of difedif 0.2 liters of liquid Areke with an average alcohol content of 45% has been obtained with average time of 65 minutes. On average it takes 25 minutes to reach the boiling temperature of ethanol at atmospheric pressure of 0.722atm. Similarly, the condenser water temperature reaches 59.1 ℃ after ethanol vapor condensation.