Small Ammonia Absorption Units in RVs

[meanu]

Hello Menbers

This is a reply post from zeotrope [Germany] 2011]



Re: Small domestic absorption fridge

Hello, meanu is right, the electrolux cycle contains usually ammonia, water and hydrogen, chrome6 as inhibitor. I had to investigate some of these interesting machines. They vary in mixture, Ammonia/Water 18/82% to 25/75% and the are filled up with hydrogen 17 to 22 bars. I modeled some of the machines in software, it's quite
interesting. So if u want to rebuild one sidkale, be prepared to use Chrome6 (poisonous) as inhibitor or good
steel alloys for production.

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Has anyone tried using Stainless Steel 316 for the tubing instead of Steel ? Then the need for Sodium Chromate corrosion inhibitor would be solved.

Does Hydrogen leak through the microstructure of Stainless Steel 316.

I know these are difficult questions, but some of you are a lot smarter than me in this area.

Are you still around "zeotrope" ?

Kind Regards

meanu

[hookster]

Austenitic stainless steel is generally considered acceptable for hydrogen service, whereas martensitic stainless steel is not. With current heat pipes and absorption fridges being is use for numerous years in steel pipe and leakage rate extremely small, the cost of chemical grade stainless does not appear to be worthwhile.

[meanu]

hookster

Hello hookster

Thankyou for that information. I will be sourcing my Stainless Steel tube at the scrap yard at $4.00/kg, so price is not a problem.

Thankyou again.

Kind Regards
meanu

[spimps]

I have a few brand new absorption units in my loft,small domestic/caravan ones which date from mid 1970's dont know if there would be a market for them in the UK.