Can a calorifier be fitted to a seawater cooled engine.

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Jcorstorphine

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At present I am looking at a boat with a Yanmar direct seawater cooled engine.

Is it possible to somehow link the engine block to a calorifier with perhaps some form of circulating pump.

One concern I have is the possibility of electrolytic problems between the cast iron block and the copper coil in the calorifier.

Any thoghts
 
Jcorstorphine said:
At present I am looking at a boat with a Yanmar direct seawater cooled engine.

Is it possible to somehow link the engine block to a calorifier with perhaps some form of circulating pump.

One concern I have is the possibility of electrolytic problems between the cast iron block and the copper coil in the calorifier.

Any thoghts
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It's physically possible, but hardly worth it because the seawater just doesn't get hot enough - not much more that 50oC, as I recall.
 
Depends, largely on the power output of the engine. A raw-water cooled 20hp engine would be OK, a 10hp probably wouldn't.
 
Engine is 30 HP and I just want water for shower so 50 would be ok. In our Motorhome we set the gas water heater to 45 and that gives a nice shower when mixed with a little cold. As to getting the hot water out of the block, I was thinking about using a 12 volt Solar heating pump to feed the coil.
 
Bit of a myth that the water will not get hot enough - it runs at 70 degrees. Will just be a bit slow heating up compared with a fresh water cooled engine.

There is no connection between the copper coil and the iron block so there can be no galvanic action.
 
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I have a calorifier on my 30 year old benneteau powered by volvo penta 2003, raw water cooled. Works well, stores 26 litres of warm water, plenty for showers. Sorry can't help with plumbing diagram but it runs off the one pressure pump.
 
Yes, I get piping hot water from my raw-water cooled 20 hp Bukh. I do have an additional (electric) pump to circulate the water from the engine to the calorifier and back, which is a pretty standard arrangement.
 
There is a page on the topic on my website https://coxengineering.sharepoint.com/Pages/Calorifier.aspx The water in a directly cooled engine is plenty hot enough to heat a calorifier - typically within 15 minutes the hot water temperature is too high to hold your hand under. The mistake made by most people who think it does not work is to try to divert the water from the engine to the elbow through the calorifier. This is a mixture of engine and bypass water, so only gets to around 40 C. Sadler built hundreds of boats with raw water cooled Bukh engines and calorifiers and all work well. Plenty of Volvos have also been converted, as shown on the web page.
 
JumbleDuck said:
It's physically possible, but hardly worth it because the seawater just doesn't get hot enough - not much more that 50oC, as I recall.
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Sorry, but this is wrong. I've got a seawater cooled engine with a calorifier (as shown on vyv_cox's web pages) and it produces very hot water - too hot to hold your hand under - after half an hour or so running. As Vyv has said, I suspect it depends on exactly how the calorifier is plumbed in.
 
Iminei said:
I've considered this - is it worth attempting with a Yanmar 1GM10?
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There is a school of thought that says that a small engine (=single cylinder) may not produce enough heat for both the engine and a calorifier. The engine may then run cool, accelerating wear. However, I have also read accounts of people who have fitted one but have no idea how the coolant temperature may have been affected. If you are tempted to try it, fit a small one.
 
One can do some back-of-fag-packet sums. My boat requires about 8kW from the engine to be driven along at 5.5 to 6kts. All diesels are about 40% efficient and need to dissipate as heat about 60% of the energy taken from the fuel, ie 1.5 times tat put into the water. So in my case that's 12kW. Most domestic immersion heaters are 3kW, so at cruising revs I could heat the water of 4 houses from my waste heat alone. A smaller boat will take less power - maybe only 1/4 of mine - but that's still enough for one house!
 
jdc said:
One can do some back-of-fag-packet sums. My boat requires about 8kW from the engine to be driven along at 5.5 to 6kts. All diesels are about 40% efficient and need to dissipate as heat about 60% of the energy taken from the fuel, ie 1.5 times tat put into the water. So in my case that's 12kW. Most domestic immersion heaters are 3kW, so at cruising revs I could heat the water of 4 houses from my waste heat alone. A smaller boat will take less power - maybe only 1/4 of mine - but that's still enough for one house!
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That assumes that all the waste heat is absorbed by the coolant. A rule of thumb is that a third of the fuel is used in driving, a third goes into the coolant and a third passes out of the exhaust pipe. Given that raw water cooled engines run cooler and take longer to warm up, due to ingestion of cold water rather than pre-heated, the idea that running a calorifier could result in both an extension of the warm up time and the overall maximum temperature seems reasonable. Also, you are assuming that the boat is being driven at maximum power, which is definitely not everybody's practice.
 
Many thanks for all replies. I am just getting a short list together of possible boats and I was concerned that the boat with a seawater cooled engine could not run a calorifier, hence no possibility of fitting a shower.
 
vyv_cox said:
That assumes that all the waste heat is absorbed by the coolant. A rule of thumb is that a third of the fuel is used in driving, a third goes into the coolant and a third passes out of the exhaust pipe. Given that raw water cooled engines run cooler and take longer to warm up, due to ingestion of cold water rather than pre-heated, the idea that running a calorifier could result in both an extension of the warm up time and the overall maximum temperature seems reasonable. Also, you are assuming that the boat is being driven at maximum power, which is definitely not everybody's practice.
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Well that's obvious if I may say so. Of course not all of it can go into the calorifier, but the purpose of the back-of-fag-packet was to show that there's loads of heat available, so not to worry, it's pretty much always enough (for a calorifier). As for I 'assumed the boat was beong driven at max power' I certainly didn't: I assumed it was being driven at the very moderate power of 10HP, which is ony 20% of the rated HP of my engine as I thought that more reasonable. I was then saying that even if you have a smaller boat which takes less power to drive, say only 2.5HP, then you'll still have heat enough. Do you disagree and feel that you won't get enough heat for a calorifier from, say, a 10HP engine?
 
I have one on a buhk 48 and the water gets too hot to touch.
It's fairly old and has sprouted a couple of leaks this year on the fresh water side.
 
AntarcticPilot said:
Sorry, but this is wrong. I've got a seawater cooled engine with a calorifier (as shown on vyv_cox's web pages) and it produces very hot water - too hot to hold your hand under - after half an hour or so running. As Vyv has said, I suspect it depends on exactly how the calorifier is plumbed in.
Click to expand...

I am duly corrected. Thank you.
 
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