Battery helper schemes

alfu

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Jan 12, 2017
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Batteries are not the only form of energy storage; there are several useful types, and a well-designed off-grid facility should take advantage of them. These are energy storage media that can store energy (either produced from wind and solar pv or solar thermal) that can offload the energy storage burden on a battery array.

Here are some that come to mind:

Compressed air:
  • Any power tool that runs from electricity could possibly run from compressed air, sewing machines, blenders, etc.
  • Direct diabatic expansion air conditioning.
  • Aquaculture aeration.
Electric vehicle charging:
  • Charge a car while the sun shines, then use the car as a battery to run an inverter to power other loads
  • Transport
Load management:
  • Prioritizing: electronic control circuits could be developed that could prioritize electric loads during sun hours; when a priority load no longer needs power, that power can be passed on to the next highest priority load
  • Time of day and duration of load activation
Pumped water either into a bladder tank or a tower tank.

  • Pressurization of domestic cold water supply.
  • Irrigation systems.
  • Recovering mechanical energy by letting the load fall back (Thanks, Rerouter)
Thermal
  • Freezer: unlike a refrigerator, the temperature ofa freezer can be brought down so low during sun hours that during the night it never gets back above freezing
  • Fridge: in combination with a freezer, bottles of ice can be transferred to an un-powered fridge to make an ice box
  • Domestic space heating
  • Domestic hot water (Thanks, station240)
 
Electric car charging is a battery...

Also i would recommend avoiding the compressed air for power storage, there is not enough efficiency in either side of the process,

So far the better ones for large amounts of power on the cheap have been pumping water up a hill with a turbine to charge on the return, and building a train sled full of rocks or lead, when you have power, you drive it up the hill, and when you need power you use a generator to get power while it rolls back down,

As far as prioritising loads go, that would have to be almost entirely off grid, some countries get very upset when in residential homes you let a computer control the switching of a wall outlet, but it would work, say you need to cook dinner which will take 85% of your amps for an hour, you can switch the fridges off for that time without much issue, but that would probably have to be an overseen system, you dont want a case where the lights go out because someone ran the toaster and the microwave at the same time. which really is what most smart home users would learn through there usage habits, instead i have found a large shift in behavior when you put a system watt meter on the wall where its passed, say kitchen / loungroom area, you see your pulling 500W, but not really doing anything, and you go and investigate.
 
Rerouter said:
building a train sled full of rocks or lead, when you have power, you drive it up the hill, and when you need power you use a generator to get power while it rolls back down,

That is a rather interesting approach lol. Something tells me you would need a very large hill to get any amount of useful energy out of that though. Let's say you needed to run a washing machine for an hour. Your train would have to have a long enough hill to run down closely and generate electricity for an hour?
 
Another type not mentioned in pumped hydro storage.
At a basic level, 3 phase motor connected to a water turbine blade, run the water downhill to generate power, put power into the motor to pump the water back into the storage at the top. No reason this cannot scale down to smaller sized dams/tanks.
 
station240 said:
Another type not mentioned in pumped hydro storage.
At a basic level, 3 phase motor connected to a water turbine blade, run the water downhill to generate power, put power into the motor to pump the water back into the storage at the top. No reason this cannot scale down to smaller sized dams/tanks.

I don't understand how that would be efficient. Wouldn't there be a lot of energy wasted in the form of heat by the pumps? They pull a lot of current.
 
mike said:
station240 said:
Another type not mentioned in pumped hydro storage.
At a basic level, 3 phase motor connected to a water turbine blade, run the water downhill to generate power, put power into the motor to pump the water back into the storage at the top. No reason this cannot scale down to smaller sized dams/tanks.

I don't understand how that would be efficient. Wouldn't there be a lot of energy wasted in the form of heat by the pumps? They pull a lot of current.

That's not quite how it works ......

Theres a seperate route for the water being pumped back up into the reservoir, using very efficient water pumps - this occurs when there is a surplus of energy production (for example from nucs) as they tend to run flat out constantly.

When there's a grid demand, the water is dropped down (seperate route) to water turbines - it's rather a long drop so given the advantage that gravity gives overall the round trip loss make this a feasible system.
 
mike said:
station240 said:
Another type not mentioned in pumped hydro storage....

I don't understand how that would be efficient. ...

Almost anything we can do with solar energy (an innately distributed resource) is efficient compared with prospecting for oil, drilling for it, pumping it to the surface, pumping it to refineries, refining it into gasoline and then carting that everywhere. The only reason oil got a foothold as an energy source is that it was easier than hunting whales.
 
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