what uses less energy? microwave or toaster oven?
I want to lower my electric bill, please send ideas.thanks.
shut your hot water heater off while your at work, makes a big difference.
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Assume a wind turbine with a hub 50.0 m above the ground, a rotor diameter of 50.0 m, and a wind-power conversion efficiency of 25%. The turbine operates in an area with an average wind-power density of 500 watts/m2 at 50 m altitude. How much electrical energy (in kWh) can the wind turbine generate in a year?
The question is written to allow for a rather simple solution, unlike the challenges of real wind turbine power and energy estimation.
Energy = Power x Time
Electric power produced = conversion efficiency x gross wind power
Gross wind power = power density x turbine swept area
So, with all the equations at hand, we can solve the problem.
Turbine swept area = 2 x pi x (25 m)^2 = 3927 m^2
Wind power density = 500 W/m^2
Thus, Gross wind power = 500 W/m^2 x 3927 m^2 = 1.9635 x10^6 W = 1.9635 MW
Electric power produced = 0.25 * 1.9635 MW = 0.49087 MW
Since the problem identifies the wind power as long-term average, we can calculate the average energy produced in a year.
Energy (Joules) = Watts x seconds
Energy = 0.49087 MW x 31536000 s = 15.487 x10^6 MJ
But the question asked for energy measured in kilowatt-hours (kWh).
So, Energy = 490.87 kW * 8760 h = 4300100 kWh produced in 1 year.
Unfortunately, a real wind turbine would produce this energy in an unscheduleable manner, typically peaking when the demand (load) is lowest. That's the challenge of wind energy.
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The quoted question is:
Build a wind power generator that will turn a small electric motor out of everyday items if possible.
N.B. You cannot use anything that is typically found in a science lab.
Yes, absolutely. What's more, it's actually quite easy. You won't get significant amounts of power out of it but it will run a very small electric motor so long as you use a generator that is significantly larger than the motor you are driving.
You'll need something that you can use for windmill blades and a motor that you can drive as a generator.
The best and easiest solution is to use a radiator fan from a modern car. Most modern cars use electrically powered fans and this is perfect for you because it takes care of the fan assembly and the generator in one go without the need for a complex assembly procedure. They are cheap and easy to get hold of too. Any car wreckers should be able to sell you one for under $20.
This type of fan is not the ideal configuration for capturing wind (they are designed to generate airflow from electricity, not electricity from airflow) but the advantages you get from simplifying the construction process more than makes up for this. Also, as far as I am aware, they are all DC motors which is exactly what you need.
Because a generator is identical in construction to a motor, this fan will generate electricity for you without any need for modification. All you have to do us hook up your small hobby motor to the terminals of the fan motor and put it somewhere where there is enough wind to get the fan spinning. You should be able to generate up to 12v depending on how fast you can get it spinning. If you find that it takes more airflow than you can manage to get it spinning fast enough, you can always construct a ram scoop (like a big funnel with the wide end open and facing the incoming wind and the fan across the narrow end) so that the wind is scooped in from a wider area and forced through the fan at higher speed. This doesn't need to be that strong, corrugated cardboard (like you get from cardboard boxes) would probably do the trick.
So long as you get the fan spinning at a reasonable rate, you should be able to easily power a small motor. Of course, as soon as the fan slows or stops, so does the motor so it's not really a viable solution for real world applications. It should be fine as a simple experiment to demonstrate wind power though.
If you want it to be a bit more practical (i.e. actually work in the real world rather than it just be for demonstration purposes), it would probably be better to run the motor from a battery and use the generator to recharge the battery. This is how proper wind powered systems work. However, the setup becomes more complex when you do this and some circuitry is required to manage the recharging of the battery, among other things, so unless you have some experience with electronics, I wouldn't advise it.
It sounds like this is outside of the parameters of your experiment anyway.
The motor you are going to drive should, ideally, be able to run on voltages between about 3VDC and 12VDC but cheap and easy to find motors like this one (http://www.jaycar.com.au/ShowLargephoto.asp?id=3255&IMAGE=) that is designed to run on voltages from 3V to 4.5VDC will still probably work OK for your purposes. If it is fed 12V continuously for long periods of time, it may overheat and burn out but, considering your setup, it will probably last at least long enough to meet your needs. If you do go for a low voltage motor like this and you want to make sure you don't damage it, just make sure that you don't spin the fan too fast and monitor the temperature of the motor. If it starts getting hot (i.e. too hot to touch), stop it and let it cool down for a while before you start it again. It's not too big a deal if you do burn it out though, these motors retail for about $2 so you won't exactly go broke if you kill it.
Good luck with it.
Hope this helps.
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Date: 2/11/2009 to 2/13/2009
Location: San Diego , CA
Meet leading wind power project developers, lenders, investors, and other key industry players as they gather and discuss how to finance wind’s continued growth under the new Administration and Congress.
I just moved into a 1000 sq ft apt on the 19th floor of a building & my electric bill every month has been out of control. We're barely ever here & we turn the heat off when we are gone, but it doesnt seem to be enough. Please help!!!
the worst thing to do is to turn off your heat,leave it on it takes more power to heat the house up when you get home then to leave it on, also leave your thermostat on 65-68 that helps, just put an extra layer of clothes on
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How does using a wind turbine/ sloar panels help mitigate global warming?
My school just installed solar panels and a wind turbine now they want me to say how it mitigates global warming, help!
Yes i need a long and detailed answer. Eg it helps by stopping power stations using so much coal or something. many thx.
I like the answer that adds in the concrete etc in the building of the wind turbine, coal power stations are of course made from organic tissue paper.
The same answer also suggests "there is a miniscule drag placed upon the rotation of the planet" I am sorry but there is only one reply to this idea, ha ha ha ha, If I were your physics teacher you just earned an automatic F-.
John s: I have been on this site for a while, I have ~20 years working in a science group that study both Antarctica and some climate related issues in the upper atmosphere, having said that I would say over 95% of those who contribute here have little or no idea (on both sides) what they are talking about, I would suggest a google search or the well known research groups like NASA and NOAA or the Hadley researcher group in the U.K. there are way to many conspiracy nuts and those who are just spreading nonsence here.
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With One Technique And A Few Items From A Hardware Store, You Can Reduce Your Electric Bill (.com) By Up To 65%. My Savings Are Even Greater.
A video record of the new Vestas v82 wind turbine erected on the St. Olaf campus in Northfield Minnesota
how cheap can you build a home wind turbine from ebay.co.uk
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