Experimental Investigation of Concentrated Solar Bread Baking Oven Integrated with Thermal Energy Storage

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Date

2025-01-01

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Addis Ababa University

Abstract

This research illustrates the innovative design, build, and performance testing of a solar bread oven with a parabolic trough and pebble bed thermal energy storage system. The purpose of developing such a system is to offer a clean cooking solution that can be easily accessible and affordable for the rural communities of Ethiopia, where people still heavily rely on biomass for cooking and there is a shortage of fuel. The oven along with its accompanying thermal storage unit was positioned at the focal line of the parabolic trough to absorb and store solar heat and to provide steady baking temperatures. Experimental tests were done in open air at the AAiT campus in Addis Ababa. The results indicated that the air temperature in the oven went up to 89–101°C, the bread core temperature was 77–81°C, and the pebble bed temperature climbed to 72.9-90 °C. Each test saw the baking of 20 small bread pieces (90 g each) in total. The overall system thermal efficiency was between 2.6% and 3.5%, whereas the first figure of merit (F₁) fluctuated from 0.08 to 0.107 during no-load testing. The system managed to bake the bread even though solar radiation was highly variable most of the days of the tests. Sensory evaluation made by ten persons also supported that the bread was properly baked inside although the outer part did not get brown as a result of the relatively low radiant heat. Overall, the study demonstrates that a parabolic trough solar bread-baking oven with pebble bed thermal storage can function under Ethiopian conditions, providing a clean and fuel free baking option. The results also highlight areas for improvement in insulation, optical efficiency, and heat retention for better performance.

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Keywords

Solar bread baking oven, Parabolic trough collector, Thermal energy storage (TES), Pebble-bed storage, Thermal efficiency, Experimental investigation, Renewable energy.

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