Abstract:
This study investigates the use of a solar thermal baking system with a Scheffler reflector and
basalt rocks as an energy storage medium to meet the increasing energy demands for baking while
minimizing environmental impact. The research includes design, manufacture, experimental
performance evaluation, and simulation of the system. A Scheffler reflector with 6.8 m² surface
area and 1.4 m focal length was designed and manufactured for baking 2.6 kg of dough in one
cycle. The installation of a Scheffler reflector in a specific location requires consideration of
several factors based on findings from COMSOL simulations. These factors include true north,
polar axis, declination angle, and hour angle, and they all have a significant impact on
performance. According to the baking capacity requirement, a 95*70*70 cm³ oven working with
natural convection was designed and manufactured. The findings from ANSYS simulations have
revealed an important aspect to consider when placing bread in the oven. It is not recommended
to place the same amount of bread on both the top and bottom trays of the oven, as this can lead
to uneven baking due to differences in heat distribution. Furthermore, it is advised to not place
both trays in the same direction inside the oven, as this can also result in a lack of uniformity in
baking.
The highest temperature recorded on the receiver surface during the unloaded test was 303°C at
1:15 PM, with an irradiance of 855 W/m2
. The bread baking test showed that the oven has an
overall efficiency of 42% at an average solar irradiance of 838 W/m2
. Based on the design, using
the Scheffler reflector for bread baking, it is estimated to save up to 3.5 tons of CO2 emissions and
7564 ETB in electricity costs annually. The Scheffler reflector is an environmentally friendly and
cost-effective solution that can help to reduce carbon emissions and save money on energy
consumption.
