Can water dams be made compact? If so, how much energy could a reduced sized (miniaturized) damn produce if 10ft x 10ft x10ft?
Is that even possible?
2006-08-21 07:41:58 · 18 answers · asked by Brad M 2 in Science & Mathematics ➔ Physics
Yes, I did spell "dam" wrong. 1/3 isn't bad though. Let's stay on topic.
2006-08-21 07:56:08 · update #1
Wow, fifteen answers so far and no one has bothered to do the calculations?
A hydroelectric dam converts potential energy in the form of elevated water (behind the dam) into kinetic energy in the form of electricity. Potential energy (U) is equal to the mass times the acceleration due to gravity times the height. Thus, one kg of water ten feet up (3m) has:
U = m * g * h = 1(kg) * 10(m/s) * 3(m) = 30J (J is a joule, the unit of energy)
Unfortunately the power generated by a dam is also dependent on how much water is flowing in because you can't let water through faster than it comes in or your reservoir level will drop and so will your power.
If water is flowing into the reservoir of the dam at a rate of 2 cubic meters per minute (approximately 1 cubic foot / sec), and this seems reasonable for a 10x10x10 dam on a stream or creek, then we can calculate the energy produced per unit time.
Water has a mass of 1000kg/m^3. Thus,
E=2000*10*3 = 60kJ (or 60 thousand joules) every minute
One watt (a measure of power or the rate of energy production/consumption) is a joule per second. Thus 60kJ/minute equals 1kJ/s = 1kW.
One kilowatt is enough to power ten 100W light bulbs OR three computers OR one hair drier.
In reality generators are nowhere near 100% efficient so your mileage may vary.
So it is possible to generate electricity this way, but probably not worth the expense.
2006-08-21 08:08:31 · answer #1 · answered by selket 3 · 2⤊ 0⤋
A few assumptions are nec.
If your dam is high up a hill you can get plenty of energy at the bottom of the hill.
If the flow rate is high, that will help too. Hoover dam uses 17 200 ft^2 tubes into the turbines with a 500+ foot drop to produce 2 gigawatts.
If you hade a 500 foot drop and could keep 10ftx10ft flowing you might get 50 megawatts!!
In reality you'd be doing well to have a 1 ft^2 outlet and get 500kW
2006-08-21 13:17:28 · answer #2 · answered by bubsir 4 · 0⤊ 0⤋
You can get so called "low head turbines" that will generate electricity with a head from 2ft to 10ft. You will be able to generate about 100W at 2ft and about 1kW at 10ft. Flow rate would be around 450 gallons per minute with a 2ft head and around 1000 gpm with a 10ft head.
These turbines are generally used with a DC output, a battery bank and an inverter. This is done so that energy can be stored for peak demand times.
I have seen systems like this used by remote communities in mountainous regions all around the world.
2006-08-21 08:17:34 · answer #3 · answered by Stewart H 4 · 2⤊ 0⤋
Very little. You can do the math since you do not specify head or flow.
A hydropower resource can be measured according to the amount of available power, or energy per unit time. The power of a given situation is a function of the hydraulic head and rate of fluid flow. When dealing with water in a reservoir, the head is the height of the water level in the reservoir relative to its height after it has left. Each unit of water therefore can produce a quantity of work equal to its weight times the head.
See: http://en.wikipedia.org/wiki/Water_power#Physics
2006-08-21 07:51:37 · answer #4 · answered by williegod 6 · 2⤊ 0⤋
There are a lot more factors to figure in other than just the size of the dam. Area behind the dam in water, form of electrical generation (generators), rate of flow of water. Its possible, but worthless. I'm an electrical engineer so hydrodynamics is not my specialty though.
2006-08-21 07:51:16 · answer #5 · answered by james_e_purdy 2 · 2⤊ 0⤋
If it's only 10 feet, the weight of the water won't be sufficent to generate much. It'd be something in the neighbourhood of powering a light for a fraction of a second every hour.
The power comes from the force of gravity pushing the water through heavy generators. The scale isn't linear, so after a certain point, the power starts becoming signifigant.
2006-08-21 07:48:33 · answer #6 · answered by rundvelt 3 · 2⤊ 1⤋
Depends if you could fit a generator in it. Hydro-electric plants use the force of moving water to turn a generator of course. even a 10x10 dam (er, assuming it isn't going to be in hell), can produce electricity if there is water flowing through it. Not sure now much wattage though. It would not be much.
-Dio
2006-08-21 07:50:54 · answer #7 · answered by diogenese19348 6 · 1⤊ 0⤋
truly it is posible and 1ft is 30 cms and so 30*30*30 = 27000cms
and 10cms = 1dm = litter = 1kg at temprature 4 degree centi grade
1kg = 1*(3*10^8)^2 = 9*10^16j as e=mc^2
here v have 27kgs of water so
27(9*10^16j) = 243*10^16 = 2.43*10^16j
*kg = kilograms , cm = centimeter , dm= desimeter , j =joul
(my calculations are handy so might i had made mistake)
2006-08-21 14:21:38 · answer #8 · answered by coolsober 2 · 0⤊ 0⤋
Change into metric units.
Use PotentialEnergy = mgh
Find mass of water. Since 1^m = 1000L, and 1000L of water = 1000kg...
M = volume*1000
M = 3.3*3.3*3.3*1000
M = 36,000 kg
PE = 36000(9.8)h
h= how far the water falls in your dam. h = height of fall of water. Obviously, since it's like a bathtub, there isn't a height, only a restriction of how much water is allowed to flow out. Anyways, there's probably some catch to my equation.
2006-08-21 07:59:02 · answer #9 · answered by Krzysztof_98 2 · 2⤊ 0⤋
Depends on how big the turbines are and how fast they spin.
Lights on bicycles are powered by tiny generators spun by the wheels. So yes it is possible. Anothe rexample is the alternator in your car but it spins at several thousand RPM
2006-08-21 07:58:53 · answer #10 · answered by know_l 1 · 1⤊ 0⤋