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Cake day: February 11th, 2024

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  • A cool. That is a known wide spread design. This is a very high force, I’m impressed. But it will come at a cost of displacement correct? We aim to make brickets for cooking fuels and we have a lot of groundnut shells. These groundnut or peanut shells have a a lot lignin so it is possible with wetted mass (softening)and perhaps heating with fire (lignine becomes like a glue at 200degC). After that the brickets are sundried. The bricket shape could be like icehocky pucks or at least the shape to cook with.

    I think the wooden design is not that interesting to generate, but with a pellet release and refilling in one lever go (or two steps). That would be an interesting puzzle, yes?



  • For work in Malawi I am thinking of introducing a bricket press to make brickets from biomass. One person must pull a lever and a piston is pressing biomass into a cylinder and compresses it. The end of the stroke should be stronger and less fast. And with returning of the lever the pressed bricket or pellet is pushed out and new biomass is inserted. It can be an interesting design from scratch and nice context? It would be challenging to make it convenient for the person while large pressing forces are reached (5000n)



  • I tried the same with a low cost grill iron ( to make sandwiches 🥪). With back in my mind that I not would buy another one but fix this one once it should break. The hinge broke and a few tabs that hold oneside metal in place. I glued it but after two weeks the it broke on another place. Could not live without tosties, have now a newer bigger one…I’ve tried…





  • It is an interesting these technologies you compare. Yes, a sand battery is in potential capable of storing higher temperatures if the source can generate these temperatures. We also have to look at the heat transfer that will seperate both energy buffers if seen from an application point of view. The heat transfer in sand is very low and this intrinsic insulation of sand begins to be very interesting when larger volumes are used. Water has a problem that it needs an extra insulation layer and larger volumes would be less interesting in comparison. However water is faster in exchange and is interesting as smaller buffer with shorter bursts and intake of heat.




  • Good question on the low power of motors. Most of the low cost pumps have often DC brushed motors which do not need a controller to steer but uses a brush. Once there is not enough power (in the morning and evening) I think there will be a point where the power will be too low to overcome the torque and the motor stops. The centrifugal pump can still rotate easily compared to other types so I would expect the startup current will be low as well. Panels will deliver a constant voltage while the current will drop when light conditions are dropping. I think the simplest is to search for these aQuarium pumps (24/7 performance) on 12v but I doubt many cars/trucks have built in fishtanks ^^)




  • I perhaps can help you with this. I’m working in a company that is helping smallholder farmers over the world to increase their crop yield. We used to start with a small hydropowered waterwheel but moved to solar due to the reach of the sun. I am the technical person that is sourcing pumps, solar panels, inverters etc for irrigation.

    So far as I can read your question you don’t need a lot of water and also not a lot of pressure. It is quite easy to calculate.

    • Hydraulic power need (W) / efficiencies = electric power requirement (W)-> *1.3 = solar panel (Wp)

    • Hydraulic power = 9,81 * height differencence of water (m) * liter per second you want to pump

    • Efficiencies = centrifugal pumps are approx 35% eff so (hydraulicp/0,35) *1,33= panelsize

    • halve a liter per second is sufficient for halve an acre (2020m2) of crops.

    Please if you have more questions I would glad to be of help