Diesel water heating as an option for cabin heating.

[goboatingnow]

I’m investigating an alternative to running large air ducting throughout the boat

I notice reasonable priced Chinese diesel water heaters are available. I was thinking of coupling these to PC based 250mm fan based radiators.

These are rated at about 300W per 10 degrees above ambient. In theory the water is about 60 degrees C from the heater so upwards of 900W should be possible. I was thinking of 4 fan radiators.

Anymore gone down this road ?

[rslifkin]

Going hydronic is a good idea. Much easier than running ducts everywhere and you can use the lines for radiant heat in some areas.



I wouldn't use the PC radiators though, they're likely too restrictive for water flow and it would be hard to get a good plumbing design with them. There are other fan heaters that would be more suitable, I think (or you could go with full radiant heat and no fans).

[goboatingnow]

Originally Posted by rslifkin

Going hydronic is a good idea. Much easier than running ducts everywhere and you can use the lines for radiant heat in some areas.



I wouldn't use the PC radiators though, they're likely too restrictive for water flow and it would be hard to get a good plumbing design with them. There are other fan heaters that would be more suitable, I think (or you could go with full radiant heat and no fans).

I’ve not found a good source of low cost fan radiators

The pc radiators have g1/4 connections so there is flow restrictions but I was thinking of 4 units. So overall should be enough.

[rslifkin]

Originally Posted by goboatingnow

I’ve not found a good source of low cost fan radiators

The pc radiators have g1/4 connections so there is flow restrictions but I was thinking of 4 units. So overall should be enough.

In parallel they'd probably flow enough, but you might have a hard time getting even flow to all of them. And the slower flow will lose more heat in the hoses before getting to the radiators. Hydronic systems are often plumbed in series to keep the plumbing runs to a minimum, so using the PC radiators adds more plumbing cost and complexity as well.

Something like these would work: https://www.suremarineservice.com/RE...-Air-Handlers/

You can also build your own with automotive heater cores and some 12v fans.

[Grandwagoneer0]

I installed one last year. It works pretty good. Put 2 radiators “heater cores” with fan I bought off eBay. One in rear cabin one in galley. They were $90 each on eBay. Used pex plumbing and insulated it. Used 2.5 gallon plastic tank for glycol and insulated it. Works pretty good. Been in boat in 26F and rear cabin stayed cozy. Galley was chilly but tolerable. Total cost was approx $1000 when done and lots of standing on my head running pex. I ran supply from heater and return. Then would branch off to each heater then outlet from heater to return so as not to rob heat xfer from one heater to next. Put valves on inlet and outlet of each heater to throttle amount of glycol to each one which helps a lot also

[goboatingnow]

I still don’t see the reason not to use cheaper pc fan radiators , true there Is a tube restriction but this is exactly the same as a domestic hot water radiator system.

Typically they are rated as 300-500 W at given fan speeds per 10 degrees c above ambient

Hence upwards of 1000W at 30 degree difference

Water flow balancing can easily be achieved with valves. This is similar to my domestic hot water radiator system at home. The system will be pumped and have a header /expansion tank.

Each fan radiator would have a balancing value E on its return. Each radiator would be in parallel.

I need to keep costs under €550. The heater is €350, the PC Radiator units are €35-40 each.

[Grandwagoneer0]

Hey I’m with ya. I can only speak of my system with what I used and my experience. Try it. Mine has 3 fans on each one and still really not enough air movement. Try it and see. Maybe better, maybe worse. Don’t know til ya try. I rarely put my .02 in unless have some knowledge or experience with the subject. If I don’t know I just glaze over and keep rolling as I have nothing to ad. I wish you luck with it and let me know how it does. If it’s better than what I have I’ll look into your way. Good luck and if you have any questions I can help with message me. 👍

[Cheechako]

I have installed forced air diesel heaters a couple times without extensive ducting. You can even bulkhead install with a couple of directed nozzles. On a boat, all the hot air rises to the ceiling anyway, so sure, you can install ducting through every space and try to spread it around the boat, but you are only in one part of the boat most of the time anyway... and unless your feet are right in front of a duct, they are going to be chilled.

The best unit had one nozzle directed under the table and one other directed i nto the main space. I often sat there or on that table settee to read etc. It worked great. But then, I'm a KISS guy.

Actually, when I bought that boat, (avatar) the PO had half installed a Hydronic system, the radiators took up space in inconvenient places, looked ugly and piping was everywhere. I ripped it all out and tossed it.

[goboatingnow]

Originally Posted by Cheechako

I have installed forced air diesel heaters a couple times without extensive ducting. You can even bulkhead install with a couple of directed nozzles. On a boat, all the hot air rises to the ceiling anyway, so sure, you can install ducting through every space and try to spread it around the boat, but you are only in one part of the boat most of the time anyway... and unless your feet are right in front of a duct, they are going to be chilled.

The best unit had one nozzle directed under the table and one other directed i nto the main space. I often sat there or on that table settee to read etc. It worked great. But then, I'm a KISS guy.

Actually, when I bought that boat, (avatar) the PO had half installed a Hydronic system, the radiators took up space in inconvenient places, looked ugly and piping was everywhere. I ripped it all out and tossed it.

Without running some tests I can’t verify the real ouput using the PC fan radiators , I agree conventional passive radiators are unsightly and large , for salt , they.would be aluminium and these are expensive

I’ve installed 4 hot air diesel system and this is my fallback
My experience is each cabin (3) requires ducting , else the poor insulation means you get annoying air movement and the cabin with a door closed gets cold fast.

Hence for air ducting , Ive got to run 75mm ducting , 9 metres to feed the forward cabin. I really should use 100mm main duct , but I found in the past that additional inline 12v blower half way along , allowed me to use 75mm.
I therefore think 4 outlets , 1 aft cabin , 2 saloon and 1 forward cabin is best.

Given the air system is half the price , maybe it’s just put up,with the hassle of threading the ducting

[fivecapes]

Originally Posted by goboatingnow

... the PC Radiator units are €35-40 each.

PC radiators are skinny as the demands are relatively not that high (couple hundred W?) and also pumps tend to be on the smaller side so they can't be too restrictive.

These, or these, on the other hand, are beefier yet still compact.

[warren2]

Exactly what I have done on my 45ft. 9.5 kw heater. Each cabin has thermostat so if it gets cold the heater kicks in. I used heater cores from a Lada car with 2 computer fans and a speed controller, need to put a small valve on each core because the hot water will tend to bypass the furthest core and balance everything out. (just like domestic heating system in uk.) Only trouble is 1 winter used about $1000 of fuel but i did have it set at 27 deg c. Any questions dm me.
I would say 1 core gives out about 1.8kw

[goboatingnow]

Thanks guys

[miketo]

Not definitive, but an example of one switchover.


https://seabits.com/hurricane-chinoo...eating-system/

[goboatingnow]

Originally Posted by miketo

Not definitive, but an example of one switchover.


https://seabits.com/hurricane-chinoo...eating-system/

Thanks way to rich for my blood

After analysis today Ive abandoned hydronic as it’s 3x the air system even though the pipes are a lot easier to install. I’m using a €130 Chinese unit that I’ve used elsewhere and I may add the open source Ardunio controller to boot.

So total install is about €250 for air but over €550 for water and closer to €650

[newhaul]

Originally Posted by goboatingnow

I’m investigating an alternative to running large air ducting throughout the boat

I notice reasonable priced Chinese diesel water heaters are available. I was thinking of coupling these to PC based 250mm fan based radiators.

These are rated at about 300W per 10 degrees above ambient. In theory the water is about 60 degrees C from the heater so upwards of 900W should be possible. I was thinking of 4 fan radiators.

Anymore gone down this road ?

Great way to do it look up pro heat . that's the one we had on the bayliner 3888 worked excellent . basicly what you want is similar to red dot heaters for the radiators