Heater Question - Alternative Source, (i.e. 500W)

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Old 05-21-11, 04:16 PM
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Heater Question - Alternative Source, (i.e. 500W)

Hi, new here,

small quick questios regarding electricity. Tried to do research, but can't seem to find answers for my questions, and i guess an experienced person would be able to answer them for me.

Basically, if i have a heater, that outputs 500W, how do i determine the minimum amount of volts required to power it?

I know that P=VI, and if i were to use this, assuming 1A, then i need 120V to power it. Now, if i Don't know the amperage, what would it be?

If i used solar power as the supply source, what would my minimum voltage be to power the heater?

Also, i notice a lot of things display in Wattage, for example 60W lightbulb. I typically know that 1W=J/s.. so in the case of a light bulb, is it 50J/s? seems an awful lot.
 
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Old 05-21-11, 05:00 PM
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So what are you trying to do. Power a 500 watt heater with solar power?

You would need 500volts at 1 amp to power 500 watts.

Be more specific, but do a search of ohms law/watt calculaters and you could probably figure it out.

Mike NJ
 
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Old 05-21-11, 05:06 PM
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Heater

Look at the specifications tag on the heater.
 
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Old 05-21-11, 07:13 PM
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First of all, an electric heater does not "output" watts, it draws watts from the supplied electrical power.

The voltage required is dependent upon the resistance of the heating element. The resistance must be such that the applied voltage does not cause too high an amperage (current) flow and burn out the resistance element. As such the voltage and current required of a heating element (and subsequently the watt rating) will fall in a pretty narrow band decided by the resistance of the heating element. You cannot arbitrarily change the voltage to an electric heater without severely changing the heat output.
 
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Old 05-21-11, 09:37 PM
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Photovoltaic (PV) panels are by far the least efficient way of gathering solar heat. Heating air (as in a green house) or water with pipe coils on the roof is substantially (many times) more efficient at capturing solar energy.
 
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Old 05-22-11, 01:45 AM
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Ok, so ill try to explain what i want to do. Please don't be too critical, since its just my ambition

Basically i want to buy a low heat output heater, take it apart (or keep it the same) and attach it to be source dependent on solar power (or other means of renewable energy). This will be for a project for keeping a pool (not too big, possibly 30" x 30") of water a little warm during cold season. I just want to get past this first step, and i thought that if i could somehow have enough power to give to a 500W heater, 24h a day, that would be good enough.

What i probably don't understand is, if a heater says it requires 500W, then if solar energy supplies 200W, does the heater still turn on, or does it turn on at a minimum of 500W?

Any other means of renewable energy that can operate a heater?

My next step would be to utilize a vacuum pump using the same renewable energy.
 
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Old 05-22-11, 08:03 AM
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If you're trying to heat a pool, you can make wooden boxes and coil up black tubing inside and then install a plexiglass cover. You run the water from the pump through it and the sun heats it.
 
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Old 05-22-11, 08:11 AM
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Justin's way is the best and can even give you far more heat at a lower cost. You could run the pump off solar cells. Maybe a 12v marine bilge pump.
 
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Old 05-22-11, 08:17 AM
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My wife's former house in Orlando had what looked like solar panels on the back of her roof. They were actually a water pipe grid system that heated water to heat the pool in the cooler months (if there are any). It worked so well, you didn't want to be at an inlet port when the valve was turned on! It heated the pool consistently and evenly.
I would ditch the heater, go strictly solar heated tubes, and enjoy the pool.
Of course if this is a high school final exam project.....we understand. You'll have to keep studying.
 
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Old 05-22-11, 10:33 AM
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A heater you buy will be designed/built to be use at a specified voltage. Many cases at normal household (120v) voltage. If you connected this to anything less it would maybe only get slightly warm or not work at all.

Using solar heat to heat water in black irrigation tubing works quite well. I had 100' of 3/4 tubing I used to heat some water for our small pool as I was filling it. 40 degree water would be hot in about 30-45 min.

This might be helpful: Solar Pool Heating Go down to the DIY section.
Or google "solar pool heater"
 
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Old 05-22-11, 12:12 PM
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Haha, sorry, i actually didn't mean a pool as in, a swimming pool. Although Justin, your way sounds very good if i do want to heat up water before it enters the pool.

I haven't really explained what the main reason for this is for. This system will basically be used during the winter, hence why i need a heater. I'm trying to see if this is even possible, i want to be able to heat the surface of a fish tank (no, i'm not going to try to kill the fish) by just heating the surface of the water, and letting convection do the work.

Now, Justin, if i could somehow have the water warm/hot, i could design your system under the tank (not inside the tank) and basically have radiation do the heating.

Although i don't know if there can be a smaller heater (<500W), i would like to try to find out whether using this heater to heat the surface of water is posible. during the winter, the temperature could get to -15, and although this is in an outside environment, the heat generated from the heater could very well be dissipated as soon as it is exposed. I'm also planning on constructing a structure that is able to be closed and opened to keep cold air and animals out.

If anyone hasn't really caught on, what im hoping to accomplish here is building an outdoor fish "pond" that can be sustained during the winter, without fish freezing to death, not to mention water below freezing point.

some people have said this probably won't work, but i'd like to try to prove otherwise.
 
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Old 05-22-11, 02:34 PM
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I think they make drop-in electric heaters for ponds that you just plug-in. You could get a few solar cells to power it or do what I said with black tubing. I think you can get 12v pumps at harbor freight. If you go solar cells, you will need deep cycle batteries and probably an inverter, too.
 
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Old 05-22-11, 03:33 PM
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Not to bust your bubble, but fish go dormant in the winter. All you would have to do is keep the water from freezing solid. Unless you have artsy fartsy fish that die if you look at them wrong. A neighbor of mine farms koi fish, and has 5 raising ponds. He doesn't heat them, only aerates them. You have to control the heat, and you haven't addressed that yet. Just having a heat source could boil your fish without control.
 
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Old 05-22-11, 04:02 PM
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Fish Pond

Do all the lakes in Canada get heated during the winter to prevent fish kills?

Sorry, I could not pass up the opportunity.
 
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Old 05-22-11, 06:19 PM
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artsy fartsy fish that die if you look at them wrong
I dont know what that breed of fish is????????

This is all I came up with while doing a search for "AFF".





Mike NJ
 
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Old 05-22-11, 06:48 PM
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Do all the lakes in Canada get heated during the winter to prevent fish kills?
LOL!

My grandparents use one of those drop-in things to keep the water from freezing over. The larger lakes just freeze over and only have thawed spots by where the water enters. I live in Pennsylvania.
 
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Old 05-22-11, 06:57 PM
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Mike, the one in the middle! I remember aquariums when I was younger. Fish died faster than I could replace them on my allowance. Figured I'd better let them be in their natural environment.
 
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