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Cake day: February 11th, 2024

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  • Indeed, it’s actually Wattpeak. For my work I make a difference between actual Watts and solar Wattpeak. I normally multiply by 0,75 to get the MAX power. This max power only occurs around noon as the sun goes up and down again. For energy in my home (Lithuania) I hope to get in the summer with 1kwh/M2/day from the solar panels.

    There are geological overlays graphs available that give indication on how much kWh you can get. Solar atlas is one of them. Look for kWh/kWp, multiply it by your solar installation size and you have your average available intake of energy. You can find the kWh/kWp on average per year,month and day. So you know in winter that you produce a lot less than summer



  • Wauw, that’s quite a setup. Nevermind the state of things, there is always room for improvements. First is that it works. Your intake of solar is quite low compared to your battery size. Are you also aiming for more solar and bigger inverter then? Otherwise it will take days to fill 18kwh.

    I am also aiming for a ton of water to be heated, both firewood and solar but have to rebuild the sauna stove for that. To have both stone and water as thermal storage. The stone I aim to also feed with cold in the summer. But I have to think more on that as condens forming is something risky.




  • I have studied the drying of fruits for my work. To get optimal drying the temperature should be 45-60degC with an airflow in it. Of course this design would work but the fruits will take 3 days before the moisture content is around 10%> The design would need a bit more solar surface and a small fan to make the evaporation go faster and exchange the humid air. But it will be a bit more complex though. Small chimney would also work








  • 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