Hydronic heating. cabin/water

[alaskanviking]

Originally Posted by GILow

I don’t know which of the systems described in this thread you are asking about.

FWIW, the system I built, pretty much the same as the one devised by ColdEH, does not need a pressure relief as it is unpressurised. The holding tank I built is square-ish, mainly shaped to fit neatly between the oven and the side of the boat and constructed from plywood and fibreglass. It is built into the boat so no holding straps required.

Mine has had most of a winter in Tasmania to prove itself now and it has worked well. It certainly coped fine through a winter in Adelaide, but that is at a significantly lower latitude.

ColdEH turned the conventional design on its head with his approach of storing heat in the treated coolant and I think his idea was brilliant. After a couple of years of running his design I have no hesitation recommending it to others.

Matt

thank you,

the ColdEH style system is what i was thinking of.

WAIT, you made a plywood and fiberglass tank as your holding tank? how does it hold the heat, its got to be in the 160f-180f range? did you insulate? i seen Cold EH's welded metal tank but must have missed the fiberglass tank construction. how did you do the water connections? please tell me more, very intrigued! how many liters is it?

what's the temperatures there in the winter?

https://www.engineeringtoolbox.com/f...its-d_787.html

I am a monkeys uncle! 300F degree operating temperature for epoxy fiberglass! would have never though about it. engine coolant shouldn't get hotter than 200F unless somethin is really wrong. i think i seen one of our cummins hit 280's tops before it melted down and blew its head!

[GILow]

Originally Posted by alaskanviking

thank you,



the ColdEH style system is what i was thinking of.



WAIT, you made a plywood and fiberglass tank as your holding tank? how does it hold the heat, its got to be in the 160f-180f range? did you insulate? i seen Cold EH's welded metal tank but must have missed the fiberglass tank construction. how did you do the water connections? please tell me more, very intrigued! how many liters is it?



what's the temperatures there in the winter?



https://www.engineeringtoolbox.com/f...its-d_787.html



I am a monkeys uncle! 300F degree operating temperature for epoxy fiberglass! would have never though about it. engine coolant shouldn't get hotter than 200F unless somethin is really wrong. i think i seen one of our cummins hit 280's tops before it melted down and blew its head!

Plywood and fibreglass are a decent insulator on their own, but it still needs foam. I used xps board and filled the gaps with poured foam which also helped to bond the tank to the boat itself.

Mine holds 70 litres of coolant and contains 50 meters of copper pipe as the heat exchanger.

The system works very well with uncomfortably hot water to the galley sink and endless hot water to the bathroom.

Heating is adequate but not the system's strong point. I've just got through winter in Tasmania and the power consumption of the various pumps and fans in the furnace and heater matrices was a problem. If I were to do another winter down here I'd be inclined to fit a more traditional Dickenson style of diesel heater. Also, the webasto furnace is very noisy. (Overnight temps this winter were around 5 degrees C, daytime around 12, but there were the odd nights of 0 or less. I only heat the boat to around 14 degrees C.)

But when it comes to fast heat on demand the system is excellent, as is the endless hot water.

[alaskanviking]

Originally Posted by GILow

The system works very well with uncomfortably hot water to the galley sink and endless hot water to the bathroom.

Heating is adequate but not the system's strong point. I've just got through winter in Tasmania and the power consumption of the various pumps and fans in the furnace and heater matrices was a problem. If I were to do another winter down here I'd be inclined to fit a more traditional Dickenson style of diesel heater. Also, the webasto furnace is very noisy. (Overnight temps this winter were around 5 degrees C, daytime around 12, but there were the odd nights of 0 or less. I only heat the boat to around 14 degrees C.)

But when it comes to fast heat on demand the system is excellent, as is the endless hot water.

I am trying to understand the contradictory statements. "Heating is adequate but not the system's strong point" does that mean issues are really a power consumption issue and "fast heat on demand the system is excellent" means when you ramped everything up the system heated the boat well?

the power consumption issue applies to all hydronic systems i think, what kind of pump are you using?

Thank you for all of this

do you have any pictures of the tank/foam under construction? I've seen pictures of ColdEH's metal tank, so i understand the basics, but I'm curious to see the composite tank details.

Thank you

[goboatingnow]

This thread has gone on for a while.

In my experience ( 6 Eberspscher inc hydronic ). I wouldn’t recommend hot water based systems at all , complex, troublesome , leak prone with slow response times.

Direct Air heating is far better imho. Very simple , reliable and efficient. Downside is bigger holes !!

[GILow]

Originally Posted by goboatingnow

This thread has gone on for a while.

In my experience ( 6 Eberspscher inc hydronic ). I wouldn’t recommend hot water based systems at all , complex, troublesome , leak prone with slow response times.

Direct Air heating is far better imho. Very simple , reliable and efficient. Downside is bigger holes !!

Well, as someone actually USING the system I can recommend it. It was not all that complex to construct, there have been no leaks in two years, it heats the boat well enough AND it gives me endless hot water. (Well, at least until the water tanks run dry.)

Ducted have their place too, but I'd use something like a Dickenson in preference to ducted because of the power consumption issue. And I think you can get a water heater jacket for the Dickenson, or make one easily enough.

But each to their own, I'm pretty happy with ColdEh's design.

[GILow]

Originally Posted by alaskanviking

I am trying to understand the contradictory statements. "Heating is adequate but not the system's strong point" does that mean issues are really a power consumption issue and "fast heat on demand the system is excellent" means when you ramped everything up the system heated the boat well?



the power consumption issue applies to all hydronic systems i think, what kind of pump are you using?



Thank you for all of this



do you have any pictures of the tank/foam under construction? I've seen pictures of ColdEH's metal tank, so i understand the basics, but I'm curious to see the composite tank details.



Thank you

The heating is more than capable, but the need to run electrical fans and a small pump make the power consumption problematic. The furnace itself has a built in circulation pump plus a reasonably powerful exhaust fan, so there's around 2 amps, then if you want to run the heating there's another circulation pump (in my design I use a separate pump as I wanted to avoid heat getting into the boat when the furnace was running just for hot water.) plus a fan for each heater.

A Dickenson uses no power at all.

The buffer tank holds heat all night so I just turn the heating circuit on in the morning to get instant heat.

[GILow]

Originally Posted by alaskanviking

...



do you have any pictures of the tank/foam under construction? I've seen pictures of ColdEH's metal tank, so i understand the basics, but I'm curious to see the composite tank details.



Thank you

I'm sorry to say there are no pictures. But simple enough to describe. It's a plywood box, a bit irregular in shape, to fit the shape of the hull. Inside was lined with two layers of fibreglass and epoxy then sealed with a couple of coats of waterproof membrane from Sikaflex. Big inspection hatch in the top, all six pick-up and return pipes come through the top of the tank to simplify keeping them sealed. Tank is filled with coolant to a point where there is about a 50 mm air gap at the top, again to simplify leak sealing. The 50 meters of copper pipe coiled inside act as a very good wave baffle, it is suspended in a couple of plastic frames to space the coil evenly and prevent it from rattling when under way.