Heat Exchanger

[StackedLumber]

I just got working on a ATV and got thinking . . . I've heard of people taking car radiators and using them in plenums as a heat exchanger-would a ATV radiator work just as well, and would be smaller/easier to fit into the plenum of a forced air furnace? Curiosity kills . . . .

 

[sdrobertson]

I've never worked on one but I would be concerned about the inlet size for the supply and return. You could try it for a garage heater unit with a fan but I don't think I would try it for heating a house. Get a good unit for where most of the heat transfer will take place.

 

[Duetech]

What ever you use for the heat exchanger it needs to fill the area of your forced ari plenum (side to side front to back) to force air to go through it rather than around it. Otherwise you will be mixing unheated air with your heated air and compromising the output. My plenum is 20" x 20" and that is the size of my exchanger. sdrobertson's point about the size of your water ports is very important too. The water has to flow fast enough to get the best heat transfer so a small port will restrict flow. Ideally in an automobile the inlet water and exit water are normally only a few degrees different. A large temperature drop means the water is moving too slow and the temperature of the air will never get that warm.

 

[StackedLumber]

yeah upon looking at it more, I think the inlet size constriction would cause flow problems. Too small inlet compared to what I'd need-the more volume the better. Sometimes you get working on something and have a brief thought of "I wonder" especially when you have free parts laying around.

 

[Gooserider]

The other issue to worry about with re-purposing vehicle rads is pressure ratings... Your typical pressurized boiler system is rated to blow the PRV at about 30 psi, and runs at 12-20 psi. The boiler and plumbing is normally tested to at least 60psi... An automotive system runs more like about half that, and according to one radiator service guy I asked about it, is only good to about 25 psi. I know I did some experimenting with an automotive heater core, and it was visibly bulging and making ugly noises at around 20 psi...

I would not feel at all comfortable with a pressurized system where there were components that didn't have a pressure rating significantly higher than the PRV valve... If I have an overpressure, I want to KNOW where the system will vent...

I haven't checked, but I have heard that truck / bus type units do run at higher pressures than cars do, but I don't know how much higher....

Gooserider