I would of posted this in the renewable energy forum, but I didn't think that I'd reach the technical end of it... my idea is simple, rather than using a chemical battery for energy storage, using water storage as potential stored energy for hydro power. I realize that there would be a loss in efficiency, but I question how much? Describing this as a 12 volt system makes it easier for me to relay. If I'm using solar panels that produce 20 -24 Volts at 5 amps, two things happen when chemical batteries are at either a low voltage or float voltage on a renewable system. During non peak solar times, very little voltage is being produced, if the batteries are over that voltage then no usable energy is being stored, again this happens when the batteries are fully charged, load diversion takes over and the extra voltage is dumped into a heat source. If I replace the batteries with a set of water tanks, a upper "basin" and a lower basin, and use the solar energy to directly drive a water pump from the lower to the upper, when voltage is low, only a small amount of water is being pushed until there isn't enough power to push the water with a variable water pump... but where the chemical batteries are not taking anything, water is still being pumped with a low voltage pump to the top basin. And here is the other question, is efficiency of a water pump to a battery being measured by the same voltage? Because while the chemical batteries will always absorb a certain parameter of voltage/amperage, a water pump will produce as much flow as the voltage is powering the pump. i.e. On a 12 volt system - the solar panels are producing 20-24 volts / 5 amps... only storing 12.8 volts in chemical batteries where as a water pump will be generating flow from all voltage supplied - i.e. 20-24 volts.
At that small scale, I think your frictional losses (and inefficiency of the electric motor driving the pump, etc.) would eat up any storage. I think batteries at this scale are the better bet .
While that is agreeable (I had a diagram of a much bigger system), there is still the factor of long term efficiency, where as the system above would not have to be replaced, unlike chemical batteries that would need replaced every 300 cycles or so, or within a few years. Chemical battery storage is not at all very efficient as it takes nearly double the voltage to charge within a given amount of time, while a pump will create flow from the same amount of voltage. If said system of solar is producing 24 volts, the batteries are only taking in 12.8 volts at anywhere between 5-10amps. If I coupled this 24 volt water pump - http://www.topsflo.com/dc-brushless-pump/tl-c01.html - which pumps 24 liters or 6.3 gallons per minunte with this water turbine - http://www.ebay.com/itm/5-0-GPM-DC-...ater-Pump-60PSI-RV-Caravan-Boat-/141801031271 - which produces 12 volts at an open flow of 5 gallons per minute then every minute I'm gaining a little over a gallon while still in use. This somewhat contradicts eating up of storage...
missed that link for the generator - these have 5 GPM starting - https://www.brownellmicrohydro.com/.../hydro-induction-power-micro-hydro-generators - I suppose price is a big part of it as well... in which case I have none...
You need to read up on this more. Volts aren't what's important. You need to be looking into things like amps and watts. Also, both of those products are pumps. Please find a turbine, or we can't do the math correct.
Using your topsflo link, and this link (micro hydropower), https://www.homepower.com/articles/microhydro-power/basics/what-microhydro-power I did the following seat of the pants calculation. Let's take that 24-v topsflo pump. It pumps 24L per minute using 53W of energy, and it can lift to 33 feet. We'll just assume it lifts to 40 to fit the example above. 24L/minute is about 6.3 gallons/minute. You would then need 5 of your 24-v pumps to produce the equivalent of 30 gallons per minute. That would take 265 watts (53Wx5pumps). So you can store 100 watts of electricity for 265 watts of pumping (solar) which is about 38% efficiency. A typical battery is about 85% efficient. Yes, there are advantages to the hydrostorage over batteries, but efficiency wise, you take a big hit. This article explains a lot of that, if you don't believe my numbers: https://www.homepower.com/articles/...-installation/microhydro-myths-misconceptions
Sorry, was away... That does explain it much better to me. When I began to price out the system it definitely gave the advantage to chemical batteries over a shorter period, and even the pumps and hydro electric generator would need to be replaced after so many hours as well. There are advantages to hydro storage as in this article about the Bath County Hydro Pumped Storage Facility - https://thinkprogress.org/the-insid...re-of-renewable-energy-8984e81283c#.qjyb7r5tl - "One day, it may be possible to use this extra energy (or extra intermittent wind and solar) to charge conventional battery systems. But right now, the worlds largest conventional batteries dont even come close to the production or storage capacity achieved by a large pumped storage plant like Bath County. Given the current state of conventional batteries, it is much cheaper to pump water up a hill." On the right scale this may be the way to go one day... Volts x Amps = Watts ...so voltage is part of it all... Unfortunately the link I posted after I realized I gave two links to pumps doesn't include the watts given for 5 GPM, which this hydro generator operates... https://www.brownellmicrohydro.com/.../hydro-induction-power-micro-hydro-generators, but if you can find it, it would be interesting to find the watts per the first 6.3 GPM pump and this 5 GPM generator...
