With good sunshine only lasting for 5 to 6 hours a day, GRAVITY-HYDRAULICS energy storage technology could serve the purpose of storing this solar energy during these 5 to 6 hours to be retrieved later in order to supply energy for the full 24 hours, or to supply gravity energy storage for a longer period of time. Presently the prices of photovoltaic solar cells are just beginning to make an expected very great drop, and new and better ways are needed to store solar energy. Nanosolar Inc claims to be now producing solar cells at a dollar a watt, which is ten times less than what the price has been for photovoltaic solar cells.

To get a bsic idea of Accumulator functon and operation you can read Ch. 16 in the basic book here: http://www.hydraulicspneumatics.com/200/eBooks/

This may not be what you are asking about but is a common way of storing Hydrulic Energy.

One place I have heard they use Gravity to produce energy and use extra energy during off peak hours to refill the storage system is at some of the Hydro-Electric generating systems that use water to drive Generators. At off peak times they can use the same generators as motors and replenish the water reservor by reversing water flow back into the lake.

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Energy could be stored as gravity height, with a motor to raise it, and a generator to retrieve the energy. Better would be a combination-motor-generator that does both. All methods of solar energy storage are very expensive, and even expensive batteries must be completely replaced after they wear out. Does anyone know how many pounds of concrete need to be raised a distance of one foot in one hour to equal one kilowatt-hour of energy, with a 100 per cent efficiency ? Many residential homes would be happy to store just ten kilowatt-hours of energy each day, but the more the available energy storage the better.How many kilowatt-hours of energy could be stored in one accumulator, and could a number of energy storage accumulators be installed in the same line, for obtaining a higher total energy storage ?

I believe a HP measurement is 1 HP=33,000#, 1 Ft. in 1 Minute.

So the reverse would be true??

1 HP= 0.746 kw.

Is that a way to determine what weight would produce your 10kw?

Reduced weight would mean reduced HP per foot of elevation.

Would someone please tell me if this conversion is correct, as it seems much too large to me ( what am I missing, or rather what is it that I don't understand ? ). 1 kilowatt hour = 2,655,223.8321 foot pounds, which means that to store one kilowatt-hour of energy then one needs to raise 2.65 million pounds a distance of one foot. I found this conversion at the web address http://www.onlineconversion.com/energy.htm

quote:

Originally posted by BH:
Would someone please tell me if this conversion is correct, as it seems much too large to me ( what am I missing, or rather what is it that I don't understand ? ). 1 kilowatt hour = 2,655,223.8321 foot pounds, which means that to store one kilowatt-hour of energy then one needs to raise 2.65 million pounds a distance of one foot. I found this conversion at the web address http://www.onlineconversion.com/energy.htm

Ok...first it's easier to analyze this if we use metric units only, no mix....
1W=1Nm/s which is the SI unit for power
1kW=1000Nm/s
1kWh=1000Nm/s x 3600s=3600000Nm or J which is the SI unit for energy
1Nm=0.73756217557 foot pound
3600000Nm= 3600000x0.73756217557=2655223 foot pound
VOILA!
Conversion is OK!!
Then how to interpret that in an energy discussion is another matter. I suppose we are talking about raising a sort of mass to a higher level of potential energy, like pumping water up into a container (dam). If we didnt have ANY friction to deal with, just gravity (Newton's favourite subject), it would take 1kWh to raise 2655223 lbs water to 1 ft higher level of potential energy....2655223/3600=737.56 lbs of water to 1 ft higher....in 1 second.....Oh wow....we can do a lot of work in one hour with no friction.....friction KILLS us, (I wonder if Newton died from friction???).....I HATE FRICTION!!! Un less its in my brake system....let magnetic fields fight each other (friction) like they do in an alternator, start moving the electrones, and charge batteries in the down grades.....TOYOTA Prius Hybrid!!!

Btw...2655223 lbs of water isnt that much....it equals the amount of water we get from a local, 30 sec rain shower, spread that water out on flat ground, it will only cover about 375 acres 1/32 inch deep.....wow...this will thickle all the math guys now....I apoplogize, but I couldn't resist it.....
My intention is to show how much energy we soon will start see falling down here in the PNW....ouch...its going to rain 24/7...and we only collect a small, micro-portion of it in the hydro plant dams.....The Sun is powerful.....to utilize it's power.....we have to master the losses.....

Here is a Link to the Water Powered Turbines that pump water back into the elevated reservoir when Electric demand is low.

Would you believe an Air Compressor with over 8,000 CFM Free Air that only had ONE MOVING PART and that was WATER.

Check it out:
http://cr4.globalspec.com/thread/28...d#comment301602