I'm sure I've seen heat exchangers on small engine
exhausts; the idea being to recover the generator's
waste heat while running things in the house.

It may have been on a RV generator, but I don't recall.
Does this ring a bell with anyone here?



--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

David Lesher wrote:
I'm sure I've seen heat exchangers on small engine
exhausts; the idea being to recover the generator's
waste heat while running things in the house.

It may have been on a RV generator, but I don't recall.
Does this ring a bell with anyone here?

Chris Craft direct replacement heat exchanger allows use of hot water cabin
heater in cooler climates.
http://www.go2marine.com/category.do?no=14018


--
John R. Carroll

David Lesher wrote:
I'm sure I've seen heat exchangers on small engine
exhausts; the idea being to recover the generator's
waste heat while running things in the house.

It may have been on a RV generator, but I don't recall.
Does this ring a bell with anyone here?

http://tinyurl.com/yd6vntz

--
John R. Carroll

Alas, neither cite fits the bill. One is a marine
water-to-water unit, it appears; the other URL is a
paper on engine heat. Neither is useful on a 2 cyl.
aircooled generator.

--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

David Lesher wrote:
Alas, neither cite fits the bill. One is a marine
water-to-water unit, it appears; the other URL is a
paper on engine heat. Neither is useful on a 2 cyl.
aircooled generator.


Original VW beetle heat exchangers maybe. I don't know the details from
having one, although I know some people that have, but they used exhaust
heat exchangers to heat the cabin air. IIRC the only problem was when
the heat exchangers became perforated and started passing exhaust into
the cabin air.

David Billington wrote:

David Lesher wrote:
Alas, neither cite fits the bill. One is a marine
water-to-water unit, it appears; the other URL is a
paper on engine heat. Neither is useful on a 2 cyl.
aircooled generator.


Original VW beetle heat exchangers maybe. I don't know the details from
having one, although I know some people that have, but they used exhaust
heat exchangers to heat the cabin air. IIRC the only problem was when
the heat exchangers became perforated and started passing exhaust into
the cabin air.

Yes, any plan to capture generator waste heat should include redundant
CO detectors. If going this route, the entire generator should be
enclosed to capture the heat radiated from the block as well, with
combustion air ducted in to the carb from outside, the exhaust routed
through a few turns of oversized pipe and then outside, and fan forced
cooling air over the whole mess.

The VW ones were air to air; the inner exhaust pipe was cast iron,
like a manifold. The outer part was sheet metal and soon leaked, but
that was not a hazard...it just reduced the output.

I'm hoping to heat water with the exhaust. I saw one once; I assume it
had a tubing coil wrapped around the pipe, but just got a glance at
it years back.


--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

David Lesher wrote:
The VW ones were air to air; the inner exhaust pipe was cast iron,
like a manifold. The outer part was sheet metal and soon leaked, but
that was not a hazard...it just reduced the output.

I'm hoping to heat water with the exhaust. I saw one once; I assume it
had a tubing coil wrapped around the pipe, but just got a glance at
it years back.



Check the marine engines.
We do this all the time to keep salt water out of the engine cooling jackets.


--

Richard Lamb
http://www.home.earthlink.net/~cavelamb/

cavelamb writes:


Check the marine engines. We do this all the time to keep salt water
out of the engine cooling jackets.

But those are for liquid-cooled engines; this is not one.
--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

"David Lesher" wrote in message
...


The VW ones were air to air; the inner exhaust pipe was cast iron,
like a manifold. The outer part was sheet metal and soon leaked, but
that was not a hazard...it just reduced the output.

I'm hoping to heat water with the exhaust. I saw one once; I assume it
had a tubing coil wrapped around the pipe, but just got a glance at
it years back.


--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

There are industrial ones that are pricey like these:
http://polarpowerinc.com/products/he..._exchanger.htm
http://www.ejbowman.co.uk/products/E...Exchangers.htm

I suppose you could also adapt a standard household gas fired water
heater. One of the ones with the helical gas coil inside would probably
be more efficient than the straight tube up the center type
Art.

On Thu, 11 Feb 2010 20:11:24 +0000, David Billington
wrote:

David Lesher wrote:
Alas, neither cite fits the bill. One is a marine
water-to-water unit, it appears; the other URL is a
paper on engine heat. Neither is useful on a 2 cyl.
aircooled generator.


Original VW beetle heat exchangers maybe. I don't know the details from
having one, although I know some people that have, but they used exhaust
heat exchangers to heat the cabin air. IIRC the only problem was when
the heat exchangers became perforated and started passing exhaust into
the cabin air.
To the best of my knowledge, the VW heating system directed engine
cooling air into the cabin, and very little of it at that. In 1963
they started installing a gasoline fired heater which I found totally
unreliable although the latter models were somewhat improved.
On the other hand, an "after market" accessory for the model "A" Ford
was a cast iron shroud around the manifold ducted to a butterfly valve
through the firewall into the area of the front seat passenger's
knees.
Gerry :-)}
London, Canada

"Gerald Miller" wrote in message
...
On Thu, 11 Feb 2010 20:11:24 +0000, David Billington
wrote:

David Lesher wrote:
Alas, neither cite fits the bill. One is a marine
water-to-water unit, it appears; the other URL is a
paper on engine heat. Neither is useful on a 2 cyl.
aircooled generator.


Original VW beetle heat exchangers maybe. I don't know the details from
having one, although I know some people that have, but they used exhaust
heat exchangers to heat the cabin air. IIRC the only problem was when
the heat exchangers became perforated and started passing exhaust into
the cabin air.

To the best of my knowledge, the VW heating system directed engine
cooling air into the cabin, and very little of it at that.

They were exhaust heat exchangers, Gerry, as Dave Billington mentioned.
Living in Michigan when I had my '64 VW, I became intimately familiar with
them. g

They had insufficient output, especially for the windshield defroster. By
the time the air got up there is was barely warm and the flow rate was
feeble. The original equipment just bled a bit of cooling air from the
high-pressure area under the sheet metal cooling shroud.

The cure was one or two blower-boosters that we usually bought from J.C.
Whitney. You could get one for each side. They worked like a charm.

--
Ed Huntress

In 1963
they started installing a gasoline fired heater which I found totally
unreliable although the latter models were somewhat improved.
On the other hand, an "after market" accessory for the model "A" Ford
was a cast iron shroud around the manifold ducted to a butterfly valve
through the firewall into the area of the front seat passenger's
knees.
Gerry :-)}
London, Canada

On Fri, 12 Feb 2010 02:29:18 +0000 (UTC), David Lesher
wrote:

cavelamb writes:


Check the marine engines. We do this all the time to keep salt water
out of the engine cooling jackets.

But those are for liquid-cooled engines; this is not one.

But they do cool the exhaust as well. There are water jacketed
exhausts with two coaxial pipes. The exhaust runs thru the inner pipe
and water circulates in the space between the two pipes.

Then there are water injected exhausts that have a sort of upside-down
u-trap after the engine's exhaust manifold. Water introduced into the
exhaust at the downstream side of the trap cools the gases and the
plumbing enough that rubber hose can be used beyond that point.

The water jacketed system would be the most practical for reclaiming
exhaust heat.

--
Ned Simmons

One approach is to take a (non-leaking) gas-fired hot water heater and
pipe the exhaust to go up the stack of it (in place of the burner gas
flow). You could do the same with an old oil-fired boiler, or with a gas
instant hot water heater exchanger.

You can probably find something in the boat industry, but it might be
just as fast/cheap to get one tigged up. Best if it breaks the exhaust
stream up into multiple streams, and the closer it is to the headers,
the better. Before/instead of the muffler, not after it, preferably.

One of those stainless steel flat plate heat exchangers would probably
work fine (if a large enough one was selected) until it coked up - they
are not great for cleaning.

--
Cats, coffee, chocolate...vices to live by

On Feb 10, 6:04*pm, David Lesher wrote:
I'm sure I've seen heat exchangers on small engine
exhausts; the idea being to recover the generator's
waste heat while running things in the house.

It may have been on a RV generator, but I don't recall.
Does this ring a bell with anyone here?

--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

I have not seen them for small, ie less than ~50 Hp, but exhaust to
water exchangers are common for exhaust heat recovery on larger
engines. One thing you might want to watch if making one, is that the
water vapor in the exhaust will condense, and it will be corrosive due
to sulfur content in the fuel. Hence the unit should be made of
stainless or something else that won't corrode. A simple shell and
tube unit would be easy to fabricate from some tubing. Be sure and
have a T & P valve or relief valve in case water circulation is lost.