Water cooled air cooler?

[nigelmercier]

I'm removing the water-maker from my boat as I no longer need it. I had planned to block off the water intake at the base of the hull, then glass it over on my next lift-out. However, a neighbouring boat gave me an idea, as they had water running out of a through-hull all day.

How feasible is it to pump the seawater through something like the radiator on a car, and blow air through it into the saloon?

 

[idomeneus5]

hi nigel, a couple of years ago I was investigating d.i.y air coolers, there are quite a lot of examples on the net, most seemed to use the "core" of old car heater units and re-circulate iced water through it, via a 12 volt submersible pump, every thing housed in an esky to preseve the "ice slurry" and two "computer fans" in the lid, 1 pulling air into the "box" the other pushing it out, some examples show evidence of effectiveness, with pics of temp guages, Cant see any reason why your idea wont work, only downside I can see is the moisture content of the air, cheers peter

 

[prv]

How feasible is it to pump the seawater through something like the radiator on a car, and blow air through it into the saloon?

Seems feasible, if probably bulky, but will the seawater be cool enough to make a useful difference? I'd have thought that if you don't want to go the full refrigerated hog, something along the lines of a "swamp cooler" using latent heat of vaporisation (is that the right term?) would be more effective.

Pete

 

[NickRobinson]

Interesting idea, thought probably not needed in Fleetwood...

A thought. (And I realise you want to use the through hull) Water temp drops significantly 2-3 m down, wouldn't a dangling pickup, at least while moored, boost effectiveness?

Nick

 

[Heat Exchanger Guy]

How feasible is it to pump the seawater through something like the radiator on a car, and blow air through it into the saloon?

As car radiators (and others) are generally made from aluminium this would not be a good idea, even if the radiator material was suitable for contact with sea water then there is a potential for the narrow internal tubes to become blocked. Some radiators feature turbulators inside the tubes to increase the surface area which would make the risk of blocking much greater.

Almost all of the radiator type products we supply are air-cooling products which cool a water/glycol (25%) circuit although they do also get used to cool oil and charge air too. Whenever sea water is involved (usually as the coolant) then we specify a shell and tube heat exchanger with the sea water flowing through the tubes. Over the tubes you would have the hot fluid which could be oil, water or an off-line water/glycol circuit which could then be used in the radiator.

Also the flow rate of the sea water needs to be sufficient to bring the temperature of the air/water down, otherwise if it is too slow then it'll struggle to take any heat out of the air/water at all.

Hope this helps!

 

[FullCircle]

As car radiators (and others) are generally made from aluminium this would not be a good idea, even if the radiator material was suitable for contact with sea water then there is a potential for the narrow internal tubes to become blocked. Some radiators feature turbulators inside the tubes to increase the surface area which would make the risk of blocking much greater.

Almost all of the radiator type products we supply are air-cooling products which cool a water/glycol (25%) circuit although they do also get used to cool oil and charge air too. Whenever sea water is involved (usually as the coolant) then we specify a shell and tube heat exchanger with the sea water flowing through the tubes. Over the tubes you would have the hot fluid which could be oil, water or an off-line water/glycol circuit which could then be used in the radiator.

Also the flow rate of the sea water needs to be sufficient to bring the temperature of the air/water down, otherwise if it is too slow then it'll struggle to take any heat out of the air/water at all.





Hope this helps!

Totally agree with this post. You will need to 'isolate' the sea water from your heat exchange circuit. Flow is critical so that outlet temps are as close to inlet as possible whilst removing heat form the exchanger circuit. Of course, the heat being thrown back into the sea is also a waste of energy, as is any heat generation from the exchange operation side of the system. So, the challenge must be to use as much energy as is possible to eliminate losses. Waste heat for transfer to another power medium, cold to cool your environment.

 

[William_H]

Yes as said it is not a good idea.
However if you are beset with high cabin temps then consider that the bilges are probably much cooler than the head height of the cabin. So a recirculating fan set up to suck air from the bilges might produce cooler air. The heat transfer is from sea water through the hull itself to the air.
Evaporative coolers are very popular here in west Oz. They are however hopeless if the ambient is high humidity. So great in the desert not so good on the water where humidity is always higher. You need compressor type air conditioning with huge amounts of power. ie over 1000watts for a small boat. Or just throw yourself into the sea regularly. good luck olewill

 

[William_H]

Yes as said it is not a good idea.
However if you are beset with high cabin temps then consider that the bilges are probably much cooler than the head height of the cabin. So a recirculating fan set up to suck air from the bilges might produce cooler air. The heat transfer is from sea water through the hull itself to the air.
Evaporative coolers are very popular here in west Oz. They are however hopeless if the ambient is high humidity. So great in the desert not so good on the water where humidity is always higher. You need compressor type air conditioning with huge amounts of power. ie over 1000watts for a small boat. Or just throw yourself into the sea regularly. good luck olewill