I like aluminium powder idea. And use the metal bar as heatpipe is a good idea. I would not see temperature as problem as most materials you mention can handle 800 deg. The idea is that you can draw energy from it thus cooling it. I think a molten salt chamber uses this combination of fast transfer and high temperature
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 ^^)
Glad to be of help. I think you can get away with a 12v pump as most panels of this power range are made for 12/24v. I suggest very simple centrifugal submergable pump with a bit of filtering around it and direct connection to panel. No inverter or battery, that would be way overkill in my opinion.
As an example case, if you need to pump from the pond nearby, 2m height difference and pump 0,25liter per second. ((0,25 *2 *9,81)/0,35)*1,33 = 18,6W ->20wp panel. I did not take into account the hose size butn0,25liter per second is not a lot. And every meter height difference added will add an extra 10W to the panel
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
Well, bad for you if it is a crappy option. The company doesn’t care for quality as the consumer has no other option. Hurray for Amazon, our everyday feeder. And for those working at Amazon, only one toilet break per week, as there are no other options for work!
Good job @hamtron5000, you need to place the cats somewhere 😁. We also built a cat collector last month. The trick with us was the stovepipe that did not allow combustables nearby so the pathway is very small for the cats
Unfortunately that would negate the high storage temperature of sand (up to 800 degree c) as water will turn into steam after 100deg. So it is either low temperature sand or water with lower energy density.