Homemade Icyball

Larry Hall liked the concept of the Icyball but thought it was a bit large so he made a smaller version that could be used in a standard size ice chest when he went camping. Larry Hall has supplied instructions for building you own Icyball, Larry points out that in the original Icyball pressures reach as high as 240psi during the charge cycle. Please don't try making your own unless you know what you are doing.

Larry improved on the original design by adding a shut off valve in the connecting tube so after the Icyball was fully charged it could be shut off and the cooling cycle delayed till later, when you needed it.

This is Larry's prototype so it is equipped with pressure gauges and sight windows to monitor the process.

Larry reports the cold ball itself would get as cold as 11 deg. below zero F

"The cold ball is about 5" dia. and the hot ball is about 6" dia.. I used off the shelf steel pipe end caps (weld type), aprox. 1/4" wall thickness if I remember right. The rest is just thick wall steel pipe and fittings. It's overbuilt for experimenting. On one charge it can keep an ice chest below 38 deg. F. for 24 hrs.. I never actually took it camping. I was going to make a simpler, lighter model but never got a round to it. The Icyball isn't exactly as simple as it looks- I found by experiment that you definitely need the internal bubbler tube and check valve (a very clever liquid type check valve) as shown in the patent drawings. The liquid ammonia (barely visible in one of my photos) doesn't get absorbed into the water very well without the bubbling, stirring action of the tube."


Other Home Built Icyballs
Texas Icyball 1999

The lowest temperature we measured was minus 19.1 F on the weld at the sight glass of the cold ball. How cold it got seemed to depend on the outside air temperature, the temperature of the cooling water, but most of all on heating it slowly so that you don't drive too much water into the cold ball with the ammonia vapor.

Dave Brydon

Multiple home builds ready for a fair display

Charge Cycle

Frosty Results

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