water-born central heating

[hans]

I have a 25 year old Swedish built Monsun 31`sail-boat. The boat has the original heating arrangement - a parrafin roun wick which heats a closed "tub" of water/anti-freeze mixture. There is a circulation pump and the water/anti-freeze mixture then circulates all around the bunks through a complex system of pipes and "heaters" - metal tubes with a ribbed surface giving a large surface area. The whole set-up sounds awful, but it works! However it takes ages to heat up, but then it dries the bunks lovely and gives a nice "basic" heat. We live in northern Norway at 70 degrees north. Before last summer`s criuse to Spitsbergen we installed a paraffin Taylor heater, which gives real heat.

The idea was initially to throw out the whole central-heating arrangement - mostly bacause of the long time before there`s any heat, and because the actual burner set-up takes up some much storage space next to the "wardrobe" in the heads.

I have a fresh water cooled 27hp Yanmar. The question is: can I not install a calorifier, thus heating the water when the engine is running. Do some of these come with an electrically heated option, enabling me to "plug in" while in port. The idea was then to plug this set-up to the central-heating set-up. I have no need for hot water from tap.

Could I buy a commercially avalilable calorifier-unit without the big tank, maybe my own, smaller tank and installing the unit into that? Anybody out there with experience and/or suggestions?

 

[Guest]

A couple of pionts that might be worth thinking about

1 What is the heat output from the engine and how closely does it match the heating system? you probably need 6-8kw

2 Could you simply add a mains imersion heater, the sort used for domestic hot water, to the existing tank as a pre-heat, boost, shore power addition?

3 Fit a comercial unit such as the minkuni that is desinged to run hot water central heating and does the same job but is smaller than your existing system sounds.

4 Swap the taylors for something like the a reflex stove with built in heater coil and conect this to the existing system. This last is what I am intending to fit on a similar sized boat for the advantage you point out - dry bunks. I am going to run a 'hot pipe' round at bilge level through every lokker so thet warm dry air rises through the gear - I can then keep warm by putting on the dry cloathes!

Wopuld be intersed to talk to you about the system you have and compare it to my ideas as I have never seen one in action and it might avoid pitfalls

Roly, Voya Con Dios, Glasson, Lancaster

 

[vyv_cox]

I see no reason why this would not work. I have a Yanmar 27 HP with a 25 litre calorifier. Mine doesn't have an electric immersion heater but it has the fitting for one. Most modern calorifiers have this option. Calorifiers are available in a wide range of sizes, from about 15 litres up.

In use, my fresh-water cooled engine heats the calorifier to something like 60 - 70 degrees C in about 20 minutes.

 

[Chris_Stannard]

I recently replaced the hot water tank in a Sigma 362 with a 22 litre unit from Penguin Engineering. The unit had a electric immersion heater, for use in harbour this has to be screwed into the tank. The hot water coil was an integral part of the tank and I have never seen one that separate. You also need a pressure relief valve as the pump tends to pressarise the tank.
If you wish to retain your current tank, or make your own, I guess you could do so. You have to ensure that you have a bleed point to get the air out of the system. The heat exchanger pipes will be copper for heat transfer, whilst the tank would be made fron steel. In most cases this is treated, by enamalling or a similar process, to prevent corrosion but you still need a sacrficial anode in the tank. The tank also needs to be insulated.
When you take all of these factors into account it is probably more cost effective to buy a ready made unit than to start trying to make your own, unless you have all the skills and tools

 

[Guest]

I'm wearing my heating engineer's hat! sounds like you've got an excellent system. judging by your comments of a slow response time. have you considered de-sludging the system. After 25 years ther is bound to be a build up, especially at the low points and within the radiators. For domestic and light commercial central heating systems I de-sludge them using Fernox Superfloc. Readily available an any plumbers merchant in the UK. I guess tha Norwegian plumbers merchant have smothing similar.

The de-sludging is easy, though time consuming to do. ie: lots of refills and flushing through. If I where you I'd try this first before spending lots of money on calorifiers etc.

good luck

 

[Guest]

What about a thermastat would one help ,that is if you could get one to work at low temp's
Mick

http://homepage.ntlworld.com/boats
I want big steel trawler / tug l but v/cheep or swap for tug

 

[gunnarsilins]

Water heating

Living in Sweden and sailing all year around (depending of the ice situation) I have somethging similar in my yacht.
On my boat (42 feet) I have installed 18 radiators in all, heating all cabins.
I have a Webasto diesel fuelled 9 kW heater. This keeps her warm and snug down to -20 degrees!

From a German company called "Alde" I got a 230 V heater with internal circulation pump, thermostat and a switch for chosing between 1kW and 2kW power. I use this when I have access to shore power, but it can only cope in temperatures down to about +6 if I want live on board.

From the same company I got a heat exchanger as well, this one is connected in series with the calorifier and heated from the engine.
It does not have a internal circulation pump, it runs on the one used with the diesel heater. I´m not sure but I think this exchanger can deliver something like 4 kW of output.
When it´s cold (below zero) outside this heat exhanger pulls so much heat out of the engine so it actually never reaches its operating temperature. Watch out for this on your 27 hp Yanmar. Mine is a 74 hp Perkins and probably generates much more heat.

 

[hans]

Thanks to all for helpful suggestions! I wil have a look at possibly flushing the system. I f all seems OK I think I will look for a 15 - 20 litre calorifier with an electric option and try to have this connected into the central heating system. I have room for this behind the engine, and will free up useful storage space in the heads.

Hans
S/Y "Anna"

 

[Guest]

Isotherm do a calorifier specially for boats. It is well insulated and has a sealed cell within it full of some salt or other. This takes in latent heat when the water temp. gets to about 58C (I think). The tank is designed for high pressure and they claim usually will get to about 90C in about half an hour of engine run time. The outlet mixes thermostatically with cold water to give a constant safe output temp. These units are designed for sailing yachts to make a small cylinder perform as a much larger one. Anyway its all on their website. I found it whilst looking at fridges.