Heat Exchange Help - Keel Cooler

Can you describe your situation a little more?

• what do you mean by pump station?
• what are the temperatures of both fluids?
• what are the velocities/mass flow of the fluids?
• are you thinking of using concentric pipes, or .............?

........... oh yeah - just to let you know - this calculation is pretty involved. There is no single, simple equation for it. It involves calculating heat transfer coefficients for both the inner and outer tube - which involves Nusselt, Prandtl, Rayleigh, and Reynold's numbers.

If you these "numbers" are foreign to you - you may want to download this free book (with a little info) for a little background information into what you are really asking.

http://web.mit.edu/lienhard/www/ahtt.html

You would be better off running 5 X1" copper tubes you would have nearly three times the cooling area of one 2" tube. As for the length it has to many variables to give a direct answer, Your cooling efficiency will be a great deal more than the radiator for a given cooling area, assuming the water is not to warm.

I would start with 20 ft lengths with the option to increase if required or put 10 lengths in and use a flow restrictor if running to cool. It has to be a bit of trial and error rather than running all sorts of calculations and then still having to modify things any way.

Good luck.

A typical keel cooler for that size of engine would be about 1m² in a marine application. Don't worry about overcooling, your thermostat will reduce the flow to compensate.

Although copper is clearly the better conductor you may be better off with stainless as it is physically more robust and is less likly to have corrosion problems.

I ran a 7kW gen with this system, approx 10m plastic 22mm domestic plumbing pipe and no flow around the pipe as it was just laying in a tank. It worked fine exept when i forgot and let the tank run dry ( it was our domestic water supply tank)

good luck

Chas

......you may be better off with stainless as it is physically more robust and is less likely to have corrosion problems.

In still or low velocity water stainless steel may not be a particularly good choice.............very good in medium and high velocity water and general corrosion, however, pitting is a problem.............the rate of pitting can be up to 0,5mm/year.

Don't worry about overcooling, your thermostat will reduce the flow to compensate

This is why designers of heat exchangers size keel coolers, heat exchangers, etc for specific engines??????

I do not wish to be rude, but making a statement like that shows that you do not have an understanding of the importance of cooling systems in diesel engines and the relationship that this has with lubricating oil temperatures.

Some place in my pile of reference "stuff" I have an EMD diesel marine engine installation guide that provided parameters for calculating the piping size and length for keel coolers. Check either the CAT dealer or CAT website to see if you can obtain a similar document for the Acert engine.

Also, Crane had published data for pipe coil heat exchangers. I think it showed up on a CR4 post. Check the "search" boxes on the upper right corner, type in your search term and get set to pages like http://cr4.globalspec.com/search/sitesearch?do=show&sort=textmatchrank&srch=pipe%20coil&order=asc.

Try this one for size:-

Oops! Sorry, wrong one.

Try this one:-