Aluminum coil evaporator for NH3

[coldrange]

Hi I am a purchasing officer, not a refrigeration engineer. I want to know if the Aluminum coil evaporator is good for ammonia refrigeration system? And what are the problem in the future if we use this kind of product in the future?
I got some doubt because some of our engineers agree to use aluminum coil evaporator and others are disagree.

[Magoo]

Hi Cold range.
Nothing wrong with aluminim ammonia coils, there are millions of them in service world wide.
Problems start if you clean them with chemicals, pitting corrosion etc..
Just make shaw they are seamless tubes and have an international design rating.

[US Iceman]

If coil manufacturer has a good record of building quality coils and designed to a suitable engineering standard I do not see a problem. As Magoo stated, chemicals in contact with aluminum is one area to be very careful of. Some of these cleaning agents will drastically shorten the life expectancy of the equipment.

[coldrange]

thanks for the info guys..

[NH3LVR]

They are quite common and reliable, however I have seen the distributor tubes snap off the coils where they are welded in after a few years. Very difficult to repair.
I have never had a problem with the flooded ones though.
And Caustic cleaners will destroy them very quickly. Only a problem if sanitation workers are cleaning them though.

[Magoo]

NH3LVR.
You have got it in one.
The biggest problem I have is the cleaning staff. Usually taking short cuts at end of production so as to get home earlier.
Trashing spirals, ripping galv off floors and coils, even paint off panel.
I live in fear at night, of a call to say that another spiral destacked due to ice because it was quicker to defrost with water with belt running, or a safety eaten to death with chemicals.or a safety vav blown off because someone decided that 80 'C water was a quicker defrost on a coil.

A remedy that works envolve client consent that the individuals stay back and help with repair and unpaid due to incompetence and short cutting instructions.

[NH3LVR]

NH3LVR.
You have got it in one.
The biggest problem I have is the cleaning staff. Usually taking short cuts at end of production so as to get home earlier.
Trashing spirals, ripping galv off floors and coils, even paint off panel.
I live in fear at night, of a call to say that another spiral destacked due to ice because it was quicker to defrost with water with belt running, or a safety eaten to death with chemicals.or a safety vav blown off because someone decided that 80 'C water was a quicker defrost on a coil.

A remedy that works envolve client consent that the individuals stay back and help with repair and unpaid due to incompetence and short cutting instructions.

Welcome to my life since I took a plant job!
Working without pay is forbidden here. But we have the option of charging back to the staffing company if their employess damage something. I have been doing that for two years. I will let you know if it starts to work.
I did work for a company that employed a Sanitation Manager who was present during cleanup. He was knowledgeable and industrious. It helps a lot.

[MrReds]

Hello, I’d like to take part of the thread, since it gave rise to a doubt.
I hope to lead off to a profitable discussion.
The company I am working for is buying stainless steel heat exchangers for ammonia systems since a long time.

Therefore it exists a long hisory of reliability with the use of this heat exchangers with NH3.
The competitors present a similar product, too.
Which would be the reasons to change into aluminum heat exchangers ?
Would aluminum heat exchangers give same reliability of stainless steel ones ?


Many thanks

[NH3LVR]

I would go with the stainless every time if it were my choice. But I am not paying the bills.
I was referring to evaporators, however heat exchangers can be very different depending on many factors. What you are cooling makes a big difference. If you have good luck with SS I would look the situation over very carefully before changing.

[Bhagwan Harani]

What wrong with M.S.
Fabrication is easy
Rework is easy
only class C( heavy) pipes to be used

[Winchester]

I work in a food plant and with sanitation cleaning coil they were bending them over and causing bacteria to grow in side of coil. Our plant is now installing all SS coils for food safety reasons.