Posted by spshaffer on December 19, 2006, 7:31 pm
Short and dirty...
My electric hot water tank just died, so I need to get a new one.
Before I ask my question, you'll need to know that I am space
constrained in my mechanical area where my hot water is. Additionally,
I am electrically constrained in terms of adding additional (and more
powerful) circuits, and have no access to gas.
With that being said, I'd love to add tankless and / or solar, but the
above constraints are currently restricting that.
Question: Is there an electric hot water heater out there that has heat
exchanger coils (for solar) in it so that I can make that connection
Posted by Gary on December 19, 2006, 9:28 pm
I'm not sure what the attraction of a tankless electric would be? The good tank
type electrics are have an energy factor of around 0.95, so I don't see how a
tankless would save much if any money. It would probably take a larger circuit
than you have now, and would put a limit on the rate at which you could draw
water. Greenhouse gas wise, electricity (at least in the US with mostly coal
generated power), is the worst, but it seems like a tank or tankless is going to
be equally bad that way?
Solar would be good!
The first solar water heater listed here:
Uses the Butler wand style heat exchanger that can be added to most electric
More on it here:
There are several solar water heater arrangements that are compatible with a
standard electric water heater among the ones listed here:
For example, the batch heaters, or the ones that use an external heat exchanger
and two pumps. On some of these you would gain some efficiency with a separate
hot water storage tank, but its not necessary.
Many people find they can turn the electric heating elements off completely for
the full summer.
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Posted by Robert Scott on December 19, 2006, 10:31 pm
On 19 Dec 2006 11:31:36 -0800, email@example.com wrote:
How about this: Buy a standard electric water heater with upper and lower
heating elements. Disconnect the lower element. Remove the sheet metal and
insulation. Wrap 1/2" soft copper tubing around the lower third of the tank.
Use tension straps to force the tubing to be in intimate contact with the tank.
Replace the insulation and sheet metal. Run solar-heated fluid through the
tubing whenever it is available. The statification of the hot water will make
the bottom half of the tank act like a pre-heater. You won't have as much
capacity when the sun is not shining, but if you space out your hot water usage,
you might get by.
Or perhaps you are thinking about disconnecting both heating elements and using
the whole tank as a solar preheater to some point-of-use tankless heaters. That
would work too, I guess.
Posted by SJC on December 20, 2006, 1:49 am
If you can fit an 80 gallon, you could by a solar electric.
If it needs to be smaller, you could replace with a new electric and add a