Can I use a radiator from a high performance car to cool a fuel cell system? 2

[hackofalltrades]

I need to design a portable cooling system for a fuel cell that will operate at an external test lab. The cooling system needs to reject up to 100kW (340,000 btu/hr) heat at 75C coolant temperature with 30C ambient air. I’m hoping to use a car radiator for this.

The main distinctions between our application and a vehicle application are:

-The coolant temperature at radiator inlet is 75C at full power.
-The system will be stationary.
-The system will be open to the air as opposed to mounted inside a vehicle chassis.

Very rough assumptions result in me assuming I’ll be getting ~30% the cooling power from the radiator compared to a moving vehicle application.

Some numbers I found online for ICE heat production: 100 HP motor --> 80,000 btu/hr heat to the radiator at full power. If I get 30% the cooling power from the radiator compared to a vehicle application, then I’ll need a radiator that would cool a car with max power of:

340,000btu * 100HP / 80,000btu / 0.3 = 1416 HP

I found this radiator with integral fan meant for a ford Shelby which is a 300HP vehicle. I figure I can buy 5 of these, mount them to a frame and run the coolant to them in parallel.

Is there anything key I’m missing here why this wouldn’t work? It’s so much cheaper than the chiller systems I’ve had quoted (eg $8,000) that I’m worried there’s something I’m missing.

Thanks!

 

[TugboatEng]

A combustion engine has to reject roughly equal heat from it's radiator as power from the crankshaft. Automotive engines spend little time operating at rated power and their radiators are sized accordingly. A truck radiator for a 150-200 kW (you'll need to derate some due to 75°F operating temp) application would be a solid match.

 

[GregLocock]

I used to cool a 6 cylinder Gardner truck engine running at full power with 6 VW Golf radiators, bought from a scrapyard.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[EdStainless]

We did a similar thing. Bought radiators with integrals shrouds and electric fans.
The aftermarket has hundreds of these, contact one of the companies for help.
We plumed then in parallel. The inlet was a very oversized header in an attempt to assure equal flow through each. If we saw that one had a higher outlet temp we would put a slight restriction in the outlet of it to reduce the flow slightly.

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P.E. Metallurgy, consulting work welcomed

 

[CWB1]

Is there a requirement for this to be water-air? I’m a big fan of simple and precise, esp in a research environment so would be looking into a good old fashioned cooling tower if allowed.

 

[gruntguru]

Automotive radiators would work fine but the "fan it comes with" might be under-rated with no slipstream and for continuous operation .

je suis charlie

 

[EdStainless]

There are two types with fans, ones that only cover part of the radiator and ones that cover all of it. The first type relay on vehicle motion to provide a base level of air flow, the second are usually rated for static use.
We used ones with full shrouds and two fans for some redundancy.
Also look at the power rating on the fan. If it is only a hundred Watts look for a larger one. As I recall our dual fans were each rated 2400CFM and drew over 16A. So our 4 radiator/8 fan system drew nearly 2kW@12V for the cooling fans.
Contact some manufacturers, they will custom engineer a system for you using available sizes of radiators.

https://www.griffinrad.com/index.php

https://www.flex-a-lite.com/

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P.E. Metallurgy, consulting work welcomed

 

[cibachrome]

A better option might be to acquire a water to air radiator used by homeowners employing an external wood fired water boiler. They are a lot thicker for a truck sized radiator. Then you can use a forced-air furnace blower fan to cool and with a common air temp sensing control.

 

[itsmoked]

Automotive? No way!

My 'feeling' is that with your specs you should consider a radiator that's for a stationary generator. Something in the 6 x 6 foot range and at least 6 inches thick. You will also need a fan that's about 5 hp or 3.7kW and is swinging a 5 foot blade in a ducted shroud.


Keith Cress
kcress -

http://www.flaminsystems.com

 

[Jacob Henry]

I like your train of thought / calcs. I would also design your rig to accomodate 2 more radiators or so just in case. Also note that the coolant pump needs to be appropriately sized, because the resistance of many small radiators in parallel is higher than one big one. Pipe pressure losses can be significant.