Portable heater

[npf1]

Does anyone know if there is such thing as cheapish portable heater (not mains powered) that doesn't produce condensation?

Thanks

 

[michael_w]

Don't think there is, as water vapour is a product of the combustion process.

 

[savageseadog]

If you are burning fuel then there's water, however if you use a heat exchanger the gases and condensation go out of the flue. You will normally need electricity for a fan to do this, either the flue gases have to be blown out or the air needs to be circulated through the heat exchanger and then to the heated space. You can get smallish portable space heaters that do this. An eberspacher is the smallest but not really portable, you can get things that will heat a warehouse.

 

[brownsox]

I had been wondering the same thing. And ...
Do heaters generate more condensation than cooking? Is gas better or worse than paraffin?
For a small boat (24') would a proper tilly lamp (pressurised) be enough?
What are those little gas heaters like and how long does the gas last ...
Cheers!

 

[Tisme]

My understanding is that gas and paraffin heaters both produce similar amounts of water.
A tilley lamp would produce enough heat to remove the chill from a 24 footer, but it will still also produce condensation.

 

[michael_w]

Combustion as follows: Sorry can't get the system to write subscript.

Methane (aka Natural Gas)

CH4 + 2O2 + IGNITION = HEAT + C02 2H20

Methane + oxygen + ignition = heat+ carbon dioxide + water vapour

PROPANE

C3H8 + 502 + IGNITION = HEAT + 3CO2 + 4H2O

Propane + oxygen + ignition = heat + carbon dioxide + water vapour

BUTANE

2C4H10 + 1302 + IGNITION = HEAT + 8CO2 + 10H20

Butane + oxygen + ignition = heat + carbon dioxide + water vapour.

In the absence of compressed natural gas systems in the UK, it looks like you ought to burn Propane if you want to reduce the water vapour. Please don’t forget the oxygen requirements. If you don’t burn any Hydrocarbon fuel with enough oxygen, you’ll get Carbon Monoxide.


Sorry I don’t know the chemical compositions of paraffin and diesel.

 

[Croak]

You could look at a Catalytic Heater. We have one and it seems to produce a lot less condensation and more heat for fuel burnt. I can understand more heat, as it burns the gas more efficiently, but I don't understand the lack of condensation bit.
Be very aware of ventilation, not only does the fire burn up your oxygen but however efficient it is, it will produce some carbon monoxide and nitrous oxides.

 

[reginaldon]

Croak I think(hope) I have sent you a PM (private message)

 

[bluedragon]

If you are looking for something for use at the berth for a few hours whilst working on the boat or after a winter sail, then a gas / parafin lamp, catalytic heater, or similar won't give a major condensation problem in my experience...safety is more the issue. If for prolonged use, unattended, overnight or at sea...then I wouldn't use any of the above.

 

[DaveS]

I would agree with others. The combustion of a hydrocarbon fuel produces a similar amount of water regardless of the fuel. An approximate, but useful, rule of thumb is that 1l of water is produced for each 1l of fuel (paraffin, LPG or whatever) burned. If the heater is unflued this water is delivered into the heated space where all of it, other than that removed by ventilation (aka draughts), will eventually condense onto surfaces that have temperatures below dewpoint.

This process is inevitable, but not always obvious: the surfaces in the vicinity of the heater (cabin, say) may all seem perfectly dry after the space has been warmed up enough, but if you look into enough cooler spaces (under berths, inside lockers etc.) you'll eventually find condensation. Of course when the heater is turned off, more condensation will be produced as the previously heated air cools. As the previously heated surfaces fall below dewpoint, condensation will appear there too.

There really is no escape. As a method of trying to keep a boat warm and dry while the weather is cold and damp, the use of unflued combustion heaters is always doomed to failure.

 

[Croak]

I Didn't recieve the pm