Ingemar Saevfors
ingemar@saevfors.se
Kallangsvag 73, 18144 Lidingo, Sweden +46 703936761 www.saevfors.se
Architect/Urban planner with longtime lnks to Africa, the Americas and SE Asia, specializes in innovative building technologies for low income regions.
IN FOCUS NOW: The daunting perspective of housing another three billion people until 2050 is now further exacerbated by the fast climate change.
Construction News: A bamboo-based roof cover?
To replace the metal corrugated sheet, which turns the roof into a hot bake oven daytime. Corrosion is another issue. A bamboo mat coated with a thin asphalt layer makes a waterproof roof cover. On top of the sticky asphalt, a thin layer of white sand is spread to protect against the sun. For details:
Details: Asphalt+Bamboo Rolled_out_Roof.pdf
Watch explanatory Youtube:
https://www.youtube.com/watch?v=xu4vKvVoXW4
Agri-Voltaics:
An intensified focusing on solar energy is now world-wide. However, solar panel parks of the quantities needed will demand enormous space on fairly flat land. The challenge will then be to sacrifice farm-land for a constantly growing world population.
Recent progress with transparent solar panels can also be combined with agriculture. Large structures supporting the transparent solar panels may permit sufficient light for farming below. Some crops can even have a certain advantage by the protection from scorching sun and violent down-pours of tropical rains.
A totally planar surface is important for solar panels. Such support structures, often in form of space frames, are today mostly made from aluminium profiles, often more expensive than the solar panels they support. The same structures could actually be made from bamboo, a local material made resistant to insects by low-toxic borax treatment. The cost difference compared to aluminium is gigantic. In addition, the benefits for rural livelihoods are obvious.
A pilot project is now under planning where the feasibility and cost consequence could be explored. Space frame structures of 16 x 16 m will be built allowing 4 m gaps for drainage/irrigation canals and access paths in between. Such a single unit 16x16 could already be instrumental to an evaluation of the concept.
More details...SolarPanelFixture
Solar panel fixture to PetCrown, bamboo space frame connector.
Stress analysis by KTH (Royal Institute of Technology, Stockholm) of the bamboo poles, considering upwind wind effects of 30 m/s, indicates a max axial compression force of 9.8 kN. (Corresponding to 14.3 MPa, much below allowable limit.)
