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Moroccan researchers have studied the energy saving potential of photovoltaic systems integrated into walls made of biological building materials in rural areas. They claim that solar-powered earthen houses could achieve a levelized cost of electricity (LCOE) of $0.218/kWh.
New research from Morocco indicates that integrating locally produced bio-based building materials with photovoltaic panels could help achieve carbon neutrality in rural housing. According to scientists, the thermal properties of bio-based walls have recently been improved by the construction industry, and prices remain at “ultra-low” levels.
“The research emphasizes achieving significant energy savings and improving interior comfort through the integration of photovoltaic systems and bio-based materials,” researcher Sara El Hassani explained to pv magazine . “We use a combination of passive and active strategies: passive approaches include the use of local eco-friendly materials for insulation, while active approaches involve the introduction of renewable energy techniques.”
They used locally produced Alpha fiber such as adobe and local clay soil as a binder, mixed at a weight ratio of 8%. They also created a comparison sample using only clay soil. These mixtures were pressed into a mold to create experimental bricks for analysis. After testing the bricks, they created and simulated a thermal profile for each of them in a practical case.
“The building consists of two bedrooms and a living room, with a total area of ??40 m2,” explain the academics. “To be representative, it is assumed that the building is located in the city of Oujda and is occupied by three people.”
The researchers improved the thermal resistance of a 45 cm thick wall from 0.549 m2K/W in the clay soil-only bricks to 1.125 m2K/W in the combined mixture. They also increased the time lag of the building envelope from 18.5 hours to 23.2 hours. Retardation measures how quickly a material responds to changes in temperature.
Under simulated semi-arid climate conditions in eastern Morocco, the biomaterial demonstrated intelligent behavior, the research team reported.
“For example, on the coldest day, the biomaterial wall increases the interior temperature by up to 1ºC, which could be very effective in the energy consumption of buildings during winter seasons,” the researchers noted. “In addition, on the hottest day, the same mixture has caused a reduction of up to 2 ºC.”
Overall, the bio-based walls reduced the simulated maximum heating loads by around 24.3%, and cooling loads by around 26.7%.
“All these findings support the use of plant fibers as a sustainable practice in the development of local and efficient adobes to improve passive heating and cooling in arid and semi-arid rural regions,” the scientists say.
The researchers proceeded to determine the PV system needed for the case study home based on the heating loads. Using optimization software, they identified the most cost-effective system, with 6.01 kW of capacity.
The total cost of this system, including capital, operating and replacement costs, less a salvage value at the end of its 25-year useful life, was $11,560. With these values, the system achieved an LCOE of $0.218/kWh.
“These results indicate that combining available solar energy with locally produced biological building materials may be a viable method to achieve carbon neutrality and build low-cost, highly energy-efficient rural housing,” the researchers say. |
