Steven Harris is Still Taking Energy Questions....

I know there was a technological glitch, but I would love it if you could answer my question about electric assist bicycles and trailers in this section.
Thanks,
John S
PDX OR

I have a question. Rather than charging a battery with solar is it practical to run panels directly to an electric water heater element?
If so would one need an element designed for the panel array or would an off the shelf AC element do?
I am looking to avoid charge control, batteries, etc, abd this seems like a potential way to do that.

You'd NEVER run solar electricity to an electric element in a water heater. It would be the most wasteful expense known to man other then the federal government. You're taking 100% sunshine, turning it at 12% into electricity, than taking that electricity and heating water. When all you have to do is put the water into the 100% sunshine and heat it up with the sun directly.

I have the most simple, easy to use hot water heating designs in my book Sunshine to Dollars at http://www.KnowledgePublications.com look for it on the main page and in the page under solar. After you see how easy it is, I don't think you are going to want to go your route.

Heating elements for 120 volt hot water heaters are around 1500 watts, and for 240 volt water heaters they are 3000 watts. Do you really see yourself spending the money for 1500 watts of panels just to heat water. Heating water takes a LOT of energy. 1 BTU / Lb of water / degree F. A 100 watt panel would make 341 BTU's per hour and there are 8.3 lbs of water per gallon. There are 6 solar 'hours' in a day. By time you average in the sunrise, sunset, the off angle of the sun, plus the changes in the seasons, the max output of your panel (if in AZ) would be 6 hours, so if you wanted to raise 60 degree water up to 120F thats a degree rise of 60, you are making 341 BTU's max per hour for 6 Hours, so 6 x 341 = 2046 / 60 degrees F = 34.1 lbs H2O / 8.3 lbs water per gallon = 4.1 gallons of water you just heating in one day. A $10 'solar shower' from walmart has better performance than that.

Steve

William Bronson wrote: I have a question. Rather than charging a battery with solar is it practical to run panels directly to an electric water heater element?
If so would one need an element designed for the panel array or would an off the shelf AC element do?
I am looking to avoid charge control, batteries, etc, abd this seems like a potential way to do that.

standard practice in UK using dc elements instead of AC.

http://solarimmersion.co.uk/

r john wrote:

William Bronson wrote: I have a question. Rather than charging a battery with solar is it practical to run panels directly to an electric water heater element?
If so would one need an element designed for the panel array or would an off the shelf AC element do?
I am looking to avoid charge control, batteries, etc, abd this seems like a potential way to do that.

standard practice in UK using dc elements instead of AC.

http://solarimmersion.co.uk/

Re reading this post I did not make it clear that you can replace standard AC heaters with DC heaters however since the introduction of the solarimmersion and similar products there is no need to replace the AC element as the controller will work with your original immersion heater.