Posted by Cosmopolite on September 25, 2008, 7:52 pm
goldenhound wrote:
> Can someone please tell me if this idea is feasible:
>
> I'd like to pre-heat the water in my water heater (gas) and was
> thinking that I could coil some copper tubing (or pipe same ID pipe as
> the water supply) inside the vent pipe (about 4' in height) and take
> advantage of the heat from the exhaust to pre-heat the water.
>
> The normal-sized 4' vent pipe would be replaced with a bell-reducer on
> both top and bottom and use a larger diameter vent pipe in-between to
> hold the copper coil inside the vent pipe and not obstruct the flow of
> the exhaust.
>
> The design would be to re-route the water supply to the top of the
> coil, and have it flow down toward the tank, come out of the vent pipe
> and then into the normal cold water inlet to the water heater.
>
> What's wrong with this idea?
Great idea when the water is flowing, but if the heater comes on and
the water in the pipe is stagnant and flue temp. hits 400 - 450 deg. F,
you will have a steam plant and high pressure in the line.
Posted by goldenhound on September 26, 2008, 12:47 pm
> Great idea when the water is flowing, but if the heater comes on and
> the water in the pipe is stagnant and flue temp. hits 400 - 450 deg. F,
> you will have a steam plant and high pressure in the line.
Thank you all for your comments. These good comments were exactly
what
I was looking for. I guess its worth looking into, but now I have a
better idea
what to look out for.
Posted by Eeyore on September 26, 2008, 1:20 am
goldenhound wrote:
> Can someone please tell me if this idea is feasible:
Just get a condensing boiler.
Graham
Posted by Eeyore on September 26, 2008, 1:22 am
goldenhound wrote:
> Can someone please tell me if this idea is feasible:
RE my idea about 'condensing boilers' I believe UK building regs require
their use now in all new buildings and refurbishments.
Efficiency can exceed 90%.
Graham
XML site map
>
> I'd like to pre-heat the water in my water heater (gas) and was
> thinking that I could coil some copper tubing (or pipe same ID pipe as
> the water supply) inside the vent pipe (about 4' in height) and take
> advantage of the heat from the exhaust to pre-heat the water.
>
> The normal-sized 4' vent pipe would be replaced with a bell-reducer on
> both top and bottom and use a larger diameter vent pipe in-between to
> hold the copper coil inside the vent pipe and not obstruct the flow of
> the exhaust.
>
> The design would be to re-route the water supply to the top of the
> coil, and have it flow down toward the tank, come out of the vent pipe
> and then into the normal cold water inlet to the water heater.
>
> What's wrong with this idea?