Closed loop cooling

[drwayne]

54+ twin cat LMT 12S x457+ dreaming 90+mph

closed loop cooling
Water or glycol.. any details/reasons why/not ?

Thanks .. !

[LuckyDuc]

Electric pump circulating denatured alcohol with dry ice pellets added to the tank.

[drwayne]

I want to race this, not drink it. !
Dry ice expands during melt.. a sealed system here, m8.
My 1:1 jetboat has a heat exchanger .. but the practicality of that here is doubtful.

Thx for the thought !
W

[raptor347]

I've seen it done in a big cat with just ice and water. Very effective. Mr. U did a great job with the setup.

[LuckyDuc]

Re: Dy ice and alcohol... If you put a top side vent on the tank the gas can leave through it.

[Fluid]

Dry ice and alcohol risks over-cooling the ESC, causing breakage of parts and epoxy not designed for sub-zero temps. Far better to use ice and water; both have a high specific heat, meaning they absorb a lot of heat over time; both are easily obtained and are not flammable. We don't need or want the ESC and motor to be too cold.



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[keithbradley]

any details/reasons why/not ?

Thanks .. !

Reason why not?
I don't get why people keep bringing this up.

You're working completely backwards by going to a closed loop system. You have an extremely large supply of cool water, the only reason to circulate the same water is if you were using it to heat something. You're ignoring the one advantage boats have and handicapping yourself.

[Prop-a-Gator]

I too like to contemplate complex, breakthrough water cooling designs but water and ice is still probably best for a closed system. The phase change absorbs a tremendous amount of heat, and you know it's compatible with your cooling components. For SAW purposes on a boat that size, you probably have plenty of room for enough water & ice to last longer than your batteries. Easy enough to replenish between heats if you design for it. No need for any external heat exchanger since your medium will be colder than ambient.

Edit: I understood the OP to be asking about cooling media for a closed loop - not whether or not to use a closed loop system. I presume he has his reasons. (less drag?)

[srislash]

Reason why not?
I don't get why people keep bringing this up.

You're working completely backwards by going to a closed loop system. You have an extremely large supply of cool water, the only reason to circulate the same water is if you were using it to heat something. You're ignoring the one advantage boats have and handicapping yourself.

Keith,the Doc is in Australia and it never drops below 30 degrees celsius. We are lucky in the cooling aspect near the 49th parallel with cool water temps.Granted sometimes too cool(solid).
Shawn

[properchopper]

I've seen it done in a big cat with just ice and water. Very effective. Mr. U did a great job with the setup.

You can see the plastic bottle water resevoir in the back of the boat. Kevin and Gilbert are impeccable builders, and now hold a SAW record with this HPR.

Zi6_0532-1.jpg

[drwayne]

Keith,the Doc is in Australia and it never drops below 30 degrees celsius. We are lucky in the cooling aspect near the 49th parallel with cool water temps.Granted sometimes too cool(solid).
Shawn

Hi.
Im at the 35th ... in what is acknowledged as the driest state of the driest continent on Earth... and I run rc boats.. go figure the sense in that !
My summers range 30->45'c (85-120'f)
However, when days are that hot I tend to stay near the bar frisge

Closed loop cooling, because.. ...
1. cools things when speeds are slow.. esc heat more at partial throttle....
2. when water tempt is high ( +25'c +78'f) , cooling is dar less efficient
3. in 3 years Ive fried 2 esc due pickup blockages
4. I need ballast ( 55+ cat )
5. I thrive on complexity ( Phd Robotics )
6. consistency of water temp.. no high flow then slow flow scenarios .

I already have 6V pumps and water bags ( Sub ballast tanks) etc.
good for 1L/min ( 1Gal in 3.6min )
These shoot water 6' into air from 5/32 pipe.. water pickups dont get that range .. barely 18" at best. !

contemplating 1/2 Gal (2L) closed loop fed to both esc via 2 pumps etc.

asked here for that light bulb moment in case what I plan has flaws !

Thx




Im angling for ideas / experience / observations.

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[keithbradley]

Something you might want to consider if you haven't already:

If you use a tank to store your half gallon of water, consider using a series of dividers inside the tank with small holes drilled in the bottom. If you have no dividers and a decent mass of water, you may experience handling issues from the sloshing water.

I assume you are using ice water and no heatexchanger, as you obviously won't get a heat exchanger to cool the water better than lake temperature. The dry ice or alcohol ideas aren't bad. You could use a large water cooling plate mounted in an methanol bath or in dry ice to act as a heat exchanger. It's definitely over-complicated but I assume that's what you are going for.

[JIM MARCUM]

Gd'ay Aussie Doc Wayne. Your work is very interesting. Exactly what type/brand of water pumps are you using? I need to know where to buy a couple. I'd like to duplicate your closed loop system to cool the ESC only in my 10S2P 56" Seagad SAW cat (pic above).

Im considering using dry ice & methanol in a +- quart, baffeled container. Is Jay "Fluid" correct: "Dry ice and alcohol risks over-cooling the ESC, causing breakage of parts and epoxy not designed for sub-zero temps."? My ESCs have no moving parts, so what's to break?

I will be running twin Castle Hydra ICE2 200 Amp escs, Twin Turnigy 240 Amp ESCs for backups if the Castles smoke.

The next SAW for me is in October in LA. Legg Lake temp will likely be mid to upper 70s, and is only 10' deep. Opinions please! JIM

[properchopper]

Gd'ay Aussie Doc Wayne. Your work is very interesting. Exactly what type/brand of water pumps are you using? I need to know where to buy a couple. I'd like to duplicate your closed loop system to cool the ESC only in my 10S2P 56" Seagad SAW cat (pic above).

Im considering using dry ice & methanol in a +- quart, baffeled container. Is Jay "Fluid" correct: "Dry ice and alcohol risks over-cooling the ESC, causing breakage of parts and epoxy not designed for sub-zero temps."? My ESCs have no moving parts, so what's to break?

I will be running twin Castle Hydra ICE2 200 Amp escs, Twin Turnigy 240 Amp ESCs for backups if the Castles smoke.

The next SAW for me is in October in LA. Legg Lake temp will likely be mid to upper 70s, and is only 10' deep. Opinions please! JIM

My opinion only (after attending close to twenty SAW's) :

The majority of SAW boats don't use cooling ; short runs make it pretty much a luxury.

Gilbert and Kevin's HPR is not a purpose-built SAW boat; they do run it for sport so their longer runtimes make the closed loop system appropriate.

Hyper cooling won't save an overstressed setup.

Just my 2 rupies

[scottw]

Tony

is there a build thread on that HPR?

scott