Heat Exchanger (wetsuit)

[omnicron]

I'm in hot water now and no not the kind I wanted! This weekend was a bust. Total failure! My heater only gave me about a 10 degree temp rise. I even had bought some more copper and wrapped it on the outside and then insulation over that, no go. I'm at a loss now. I guess the crap I built was just that, crap. I'll follow the plans on Iowagold to the letter and hope for the best.

When your doing big wraps, like on 3" pipe, that no problem. When your doing small tight wraps that's when you need to take other measures.

 

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[omnicron]

I guess I'm a idiot! I have tried 4 different styles/ways on making a heat exchanger and it's still a no-go. I don't get it.my last one I built yesterday follows the one on Iowagold. My 3rd one is like Docs (goldhog) and Season 1 EP2 Bearing Sea Gold and still a no-go. I tried a modified water jacket inside the exhaust, reverse Iowagold one and no go. Tried copper bent around outside of exhaust and no go. I can't seem to make more then around a 10 degree temp rise.

I'm about $100 into this and can only make hot water if I use my camp stove on a pontoon with my mixer tank (1 gallon) on top heating up the water. Feel like a redneck and burning lots of propane.

My setup is like this, from the acc port of the pump I have a wye with shutoff valves (home and garden kind), one line to heater, other line to mixer tank. Output of the heater goes to mxer and then from mixer I have a gate valve then hose to me ( the diver). All my lines are 3/8" id. For the money I have spent already, (food out of my family of 5's mouth) I could of bought a on demand water heater.

Is there something I'm missing? I use the wye to regulate the water to the heater and mixer. When I say a 10 degree temp rise, I'm measuring at the discharge of the heat exchanger before the mixer tank.

 

[rebel003]

I'm not sure just what iowagold designs are but are you adding baffles in the and heat exchangers in the water chamber to slow down and heat the water?

 

[omnicron]

HOW_TO_BUILD_WET_SUIT_HEATER

Yes I have washers cut into the pipe (12) sticking in about 3/8" into the exhaust. Check out the link.

 

[russau]

the more of the washers that stick into the ex. the more heat itll pickup!

 

[omnicron]

the more of the washers that stick into the ex. the more heat itll pickup!

I have 12, six on each side spaced about 1" apart on each side with the sides staggered a half inch. Today I cut slits in the water jacket and installed baffles (5 staggered) down to the exhaust pipe on the top and bottom (opposite the washers) to help slow the water down and force it to flow across the washers. I ran the motor at 2340rpms, my dredging speed and still was not only getting around a 10 degree temp rise. God I would think a 6hp engine would generate enough heat.

When I shut off the water it only takes about a minute for the water to get really hot then I open the valve and in maybe 20 seconds the water is coming out cold again. I'm at a loss.

 

[2cmorau]

post some pictures of your setup, what kind of pump you using?
3/8 copper tubing worked best for me with best heat, but it vibrates and wears out, solid jacket on the other pictyre i post works for me and lasts, putz out the heat but not like coppertubing.

 

[omnicron]

Proline HP350 on 6hp Subaru EX17. It's all loaded up and buried on my trailer as I'm going up dredging today for 5 days. It's the same as the Iowa gold one except I used 1" pipe as my exhaust is 1"and the outer jacket is 3" due to bigger exhaust and the baffles I cut in.

 

[MikeMike]

If you have not already tried this slow your water to just a trickle as it goes across your muffler area and it will help heat it up. you might want to reduce your pipe hose from 3/8 to quarter inch and let it be a trickle if you have not already done that

 

[SpecJet]

removed

 

[jcazgoldchaser]

I guess I'm a idiot! I have tried 4 different styles/ways on making a heat exchanger and it's still a no-go. I don't get it.my last one I built yesterday follows the one on Iowagold. My 3rd one is like Docs (goldhog) and Season 1 EP2 Bearing Sea Gold and still a no-go. I tried a modified water jacket inside the exhaust, reverse Iowagold one and no go. Tried copper bent around outside of exhaust and no go. I can't seem to make more then around a 10 degree temp rise.

I'm about $100 into this and can only make hot water if I use my camp stove on a pontoon with my mixer tank (1 gallon) on top heating up the water. Feel like a redneck and burning lots of propane.

My setup is like this, from the acc port of the pump I have a wye with shutoff valves (home and garden kind), one line to heater, other line to mixer tank. Output of the heater goes to mxer and then from mixer I have a gate valve then hose to me ( the diver). All my lines are 3/8" id. For the money I have spent already, (food out of my family of 5's mouth) I could of bought a on demand water heater.

Is there something I'm missing? I use the wye to regulate the water to the heater and mixer. When I say a 10 degree temp rise, I'm measuring at the discharge of the heat exchanger before the mixer tank.

From that washer heater link of you posted

"This heater did make warm water and i used it as a pre heater feeding one of my better working heaters "

My first question is what is your exhaust temp? That will let you know if you're grabbing the heat or missing out on some.

Exhaust temps
Cold temp:
Hot temp:
Water flowing:

I would want the washers angled such that the water swirls all the way down the pipe.

 

[omnicron]

Well guys, still no go, If I slow the water to a trickle it get hot. My temp probe wont read the high exhaust temp but the sizzle test...drop a few drops of water on before the heat exchanger and the water sizzles and is gone in a second. I can touch the discharge side of the exchanger exhaust.

 

[MikeMike]

Please post some pics....
A pic is worth a thousand words.

 

[omnicron]

What do you need me to take pics of? If it matters I built it exactly the same as the one on Iowagold, with the exception of increasing the size for my bigger engine. I even tried both heat exchangers, copper coil and the manifold one together and still could not make hot water unless it was turned down to just above a trickle.

JC, I think you should revisit that site. He states that pic1 is of a earlier one he built that would only make warm water...
"In the 1st pic you see my port side motor/pump with one of my earlier wet suit heaters. This heater did make warm water and i used it as a pre heater feeding one of my better working heaters"

Seriously guys, I'm at wits end as to why I cant make hot water. This water was even colder now, 35 degrees.

 

[jcazgoldchaser]

His 3/4" & 2.5" pipes give an exchange area of 4.5 in^2. Yours is 6.3. The 1.8 in^2 difference is about the same as a 1.5" diameter pipe. That seems like a lot of water to me.

 

[goldhog]

We did two things to our initial config after testing...

1) We went to 20 feet of copper inside our "can" system. (We started with 10 feet of coil)

2) We bought cheap pipe insulation from Home Depot ($1.50 for 6 feet) and covered the hot water line from the engine to the diver.

We found we had a great deal of heat loss with the water traveling to the diver.
However, the first thing is to make sure the water is hot coming off or near the engine.
If it's not hot there, there's no reason to protect it.
Doc

 

[omnicron]

So what your saying JC is to choke off my exhaust and burn valves or just decrease my outer jacket size and have a smaller heating area?

Doc, in my coil type that I tried, I hade 35' of 1/4" copper coiled up inside a can. That can was mounted right next to the 90 ell on top of my head. Matter of fact all the exchangers I tried and built was mounted next to that 90, closest to the head as possible. If I could make hot water but was loosing heat (heat loss) then insulation would help. Right now I would give my left testie to make hot water!

Some days I should just stay in bed!

 

[goldhog]

Doc, in my coil type that I tried, I hade 35' of 1/4" copper coiled up inside a can. That can was mounted right next to the 90 ell on top of my head. Matter of fact all the exchangers I tried and built was mounted next to that 90, closest to the head as possible. If I could make hot water but was loosing heat (heat loss) then insulation would help. Right now I would give my left testie to make hot water!

Some days I should just stay in bed!

Hmmm.... I'll have to look and see if you posted pics.
Our exhaust dumps directly into the "can" / chamber.
Then exists out the other side after heating.
I just wanted to make sure your exhaust was actually dumping onto the coils and not just wrapped around pipe.
The can is basically red hot, not warm.
The only thing we have issues with is the water pressure varying during the run.
That will impact the temp as well.
I do have a customer that came up with an AMAZING system but it is a little complex.
If you want I can get you in touch with him.

 

[omnicron]

Hmmm.... I'll have to look and see if you posted pics.
Our exhaust dumps directly into the "can" / chamber.
Then exists out the other side after heating.
I just wanted to make sure your exhaust was actually dumping onto the coils and not just wrapped around pipe.
The can is basically red hot, not warm.
The only thing we have issues with is the water pressure varying during the run.
That will impact the temp as well.
I do have a customer that came up with an AMAZING system but it is a little complex.
If you want I can get you in touch with him.

Doc, contact info would be great.
On the coil type that I tried, first I did wrap the pipe but that didn't work. So I coiled up the tube and put that inside a can, I had a 1" exhaust pipe with a cap on the end going into the can. On this 1" pipe I had a bunch of holes drilled in the pipe so it was directing the exhaust onto the coils. I had 2 holes cut in the can, one that the exhaust pipe went in and the other hole were were I connected the exhaust system. To clarify, exhaust in was in the center and exhaust out was on the outside of the can ie: hole cut outside of the coils.

EDIT: Just had a thought, maybe I don't have enough space between the coil and the outside of the can, also my coils are fairly tight together. Could that be causing the lack of heat transfer?

To tell the truth, I really haven't want to post pics due to embarrassment...The first couple I made, I took my time and they looked professional but didn't work. After that I just hacked things together to see if it worked. Once I get something working, I would then rebuild and make it look good.

 

[jcazgoldchaser]

decrease my outer jacket size and have a smaller heating area?

If your outer jacket was 3', would that little motor ever heat up the water even if it wasn't flowing? (yes of course after a while, but to illustrate the point....).

The area of your outer pipe minus the area of the inner pipe is larger than the design you referred to. That means more water will flow through your design, presumably down the same length of pipe. That means you have more available water to absorb the heat, thus not increasing the temperature as much.

If the outer jacket is cold, and the exhaust is cold, that means you are grabbing most of the heat. That's why I asked about temps because that's how you know what part of the design to focus on.