Evaporator/condenser - aluminium tubes

With the price of copper at high levels, & predicted to remain much higher than aluminium into the future, there seems to have been a fair amount of material substitution in interconnect pipes, in Asia.

One of the forms seems to have an inner aluminium pipe, with ?plastic? external sheath.

Has anyone worked with aluminium tubes in either evaporator, or condenser?

What are the pro's & con's of using aluminium in domestic & light commercial hvac applications? :)

How are these aluminium sub-systems being connected?

I have worked with aliuminium evap coils on the Awacs Aircraft, They are very prone to perforation due to corrosion even though the piping has a coating on them. They have welded and also Brazed conections. Its a bit of a fine art is brazing aliuminium let me stress;)

^ Thanks very much, 'Quality'.

If I may, a few more questions:

What kind of tube perforation occurred?
What was the cause found to be?
What refrigerants were being used?
How was the system pressure-tested before gas charging? What pressure?
Were the evap fins aluminium?

The coating that covered the piping that was connected to the coil did get scratched off due to loading and unloading the freezer which exposed the bare aliuminum hence surface frost caused corrosion although the coil did not receive physical contact and generaly are ok.

Refrigerant Used To be R12 until We Retrofitted to R134A which is what they are now

Test Pressure 200 psi

Complete aliuminium construction

Thanks so much...

Next...

Why are aluminium tubes not being used in modern-day domestic air-conditioning systems?

Could the evaporator/condenser be compacted by the use of modern aluminium technology. Take a look at passenger vehicles, for instance - they have all aluminium air-con systems, hoses & so forth. No brazing is required at all.

Why is a similar trend not being followed in the domestic air-con industry?

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Originally Posted by desA

Next...

Why are aluminium tubes not being used in modern-day domestic air-conditioning systems?

Could the evaporator/condenser be compacted by the use of modern aluminium technology. Take a look at passenger vehicles, for instance - they have all aluminium air-con systems, hoses & so forth. No brazing is required at all.

Why is a similar trend not being followed in the domestic air-con industry?

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DesA, vehicle a/c's use Aluminium i believe, as it is easier to mold/shape into individual components, connected with removable fittings and hoses + '0' rings. Working pressure is less than domestic/ commercial air-conditioning systems. Wall thickness is quite thin on automotive, makes for better heat removal but corrosion is a problem. Maybe aluminium could be used on domestic a/c if it could withstand the pressures. Don't know if other refrigerants react with aluminium.. Mike:)