Design, Manufacturing and Performance Evaluation of Modified Solar Bubble Dryer for Pepper-Vegetable Crop

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Addis Ababa University


Capsicum (Red pepper) is a spice type plant having major role in Ethiopians daily dish and plays an important role in the national economy. On average 79% of pepper production goes to market and this results employment for urban and rural workers. For anyone who produces fruit or vegetables on a commercial basis, one of the most serious challenges is getting their products to market and selling before it spoils. The objective of this study was to design and manufacture modified solar bubble dryer to minimize and overcome the post-harvest loss of pepper vegetable crop. The experimental result showed that the efficiency of the dryer and the mass flow rate was found to be 22.6%, 3.53 x10−4kg s⁄. In addition to this the modified solar bubble dryer is portable, easy to operate and can also be used to dry any kind of vegetable. It reduces the moisture content of the pepper from about 71% to its safe storage condition of 13% in 20 hours of operation. This result was achieved within five days of experiment for four hours per day at a drying rate of 0.1 kg hr⁄. It was observed that, the modified solar bubble drier performance was 10% greater than other similar drier, and the drying time is 20% lower than that of open sun dryer. It was also observed that a uniform temperatures distribution was noticed through the drier and the temperature inside the drying chamber was greater than that of ambient temperature by an average of 3 to 5°C. Therefore, it is recommended that the modular feature of the solar bubble dryer is an option to dry vegetables to reduce the alarming rate of postharvest losses in the country.



Solar bubble dryer, Pepper vegetable crop, performance evaluation