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Author Topic: cooling question  (Read 3011 times)

32 coupe

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cooling question
« on: October 28, 2017, 06:23:42 PM »

My 6-1 runs with a Honda radiator, thermostaticly controlled fan and the orginal water pump
that I rebuilt with new bearings and seals. Works great with no problems.

My question is about the 25-2 that I have. I have run it with a 30 gal galvanised trash can that I put
fittings on to adapt hoses to. I has no water pump so it is thermo cooled. Works fine.

I would like to make it more compact and would like to add a Honda radiator with temp controlled
fan as on the 6-1.  I do have a t stat on the engine cooling manifold.

Do you guys think the coolant will thermo cycle with no water pump ?

Thanks for your time,
Gary



Metro 6/1 turning a ST 7.5 KW gen head
Changfa 1115 turning a ST 15 KW gen head
Ashwamegh 2/25
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BruceM

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Re: cooling question
« Reply #1 on: October 28, 2017, 07:31:59 PM »
We had this issue on my neighbor's propane converted 8/1.  Flow is determined by temperature drop, flow restriction, and the vertical drop or distance. 

We had to go to a deeper Honda radiator to increase temperture drop, increase tubing to 1" to improve flow, raise the radiator as much as we could (lower edge of radiator  3 feet above the valve cover), and increase our wind turbine/convection tower to 16" diameter, about 7 foot above the radiator total.  A fan is only used for backup and is rarely needed.

With the respectable temperature drop of a fan, and a 25-2??, I'd still stick to 1" pipe and the deeper honda radiator.  I'd skip the thermostat except for switching the fan to improve flow.  I'd try to keep the radiator at least 2.5 feet above the valve cover.  If you're really into compact, the pump might make it easier and simpler, and you could use the cheapest honda radiator and smaller, cheaper fan(s). This is just my guess, and I would certainly defer to a 25/2 user with first hand experience for a setup similar to your planned one.  I think on the 25 hp size I'd just go with a pump, myself. 

« Last Edit: October 28, 2017, 07:34:26 PM by BruceM »

cujet

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Re: cooling question
« Reply #2 on: October 28, 2017, 08:28:16 PM »
I have a 20/2 with an automotive rad, electric fan and water pump. The rad is mounted near the engine, and does not have much height. It will not thermal siphon with enough force to prevent overheating. I've not tried it with the rad mounted higher.

I use a Grundfos single speed, (read cheaper) (I think it uses about 25w according to my Kill-A-Watt) water pump, and run it off one of the 120v legs. The water pump starts as soon as the engine starts and the generator comes online. Works perfectly. Those Grundfos pumps can handle the heat and are exceedingly reliable.

A short video of it in action after Hurricane Erma:


http://www.youtube.com/watch?v=xxMTvE3y46I

You can see the Grundfos pump mounted directly to the water manifold at the cylinder base.



« Last Edit: October 28, 2017, 08:31:58 PM by cujet »
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32 coupe

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Re: cooling question
« Reply #3 on: October 29, 2017, 03:55:04 PM »
The Honda radiator is a vertical flow and about $90 for
the radiator and fan.
I want to keep the height at about the top of the valve cover
so I think a pump will be necessary.

I posted in the "wanted" section a while ago looking for
an original "indian" water pump. No one responded which
surprised me because all I read here says no one uses them
and everyone hates them.  I thought someone would have
one laying around unused.

I see they are available but the price is about the same as
an electric circulating pump and knowing I will have to rebuild
the indian pump right off the bat the electric pump may be
the way to go.


Metro 6/1 turning a ST 7.5 KW gen head
Changfa 1115 turning a ST 15 KW gen head
Ashwamegh 2/25
John Deere 110 TBL
New Holland TC 30

"I was sitting here reading this thinking what an idiot you are until I realized it was one of my earlier posts !"

BruceM

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Re: cooling question
« Reply #4 on: October 29, 2017, 05:44:16 PM »
I have doubts about blowing exhaust through the radiator no matter the distance.

Induced draft, which I have applied for my 6/1, uses the exhaust is used to suck cool air through the radiator via duct work, and no exhaust ever goes through the radiator.

Because of the duct work needed and more convoluted exhaust plumbing, induced draft might not be my first choice for a compact mobile system...but it could be done fairly compactly if desired. The exhaust pipe is just faired into the duct connecting to the radiator, and exhausts perhaps a foot or so behind the duct exhaust opening.  As it leaves the duct it pulls fresh air into duct through the radiator. 








cujet

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Re: cooling question
« Reply #5 on: October 30, 2017, 01:24:13 PM »
The exhaust pipe is just faired into the duct connecting to the radiator, and exhausts perhaps a foot or so behind the duct exhaust opening.  As it leaves the duct it pulls fresh air into duct through the radiator. 

Any chance for a pic or a drawing? It seems like a typical augmenter design, intended to entrain additional airflow. That, coupled with a vertical stack could induce thermal rise airflow also.

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BruceM

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Re: cooling question
« Reply #6 on: October 30, 2017, 04:07:00 PM »
Yes, Cujet, that's how it's done, though my setup is not so fancy or optimized as I need very little airflow for a 6/1.  I just have exhaust pipe in the middle of 8" duct, pointing in the direction of flow.

Here's the thread with photos of my Rumely Induced Draft setup:
http://www.microcogen.info/index.php?topic=2556.0

Note that this was a modification to an existing system, as an experiment, which worked, and I still use.  If I was designing from scratch, I'd use a small radiator well above the engine, flat to the ceiling,  in a duct box faired to an  8" exit up through  a hole in the roof.  That way the exhaust /induced airflow would also vent the engine room.

I also used induced draft via compressed air for my gas stove hood vent as my house is motorless.  Just a 1/4" copper tube exiting near the center of the 8" diameter duct,  pointing in the direction of desired flow does the trick.  Very little volume of compressed air is needed, I put a tiny regulator and needle valve on the supply.  I only use it when the chef screws up and needs a big fan...

« Last Edit: October 30, 2017, 04:25:01 PM by BruceM »

cujet

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Re: cooling question
« Reply #7 on: October 31, 2017, 12:54:39 AM »
Ah yes, I had forgotten about that thread and that setup. Thanks for the link.
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