Stainless steel vs. cupro-nickel exchangers
Stainless steel vs. cupro-nickel exchangers
(OP)
Hi all,
I'm wondering if anyone has had long-time experience with stainless steel exchangers on open-loop geothermal systems.
The reason I am asking is because the heat pumps with stainless steel exchangers are slightly less expensive (and more readily available where I am) than cupro-nickel exchangers.
So to re-iterate: is it OK to use a stainless steel exchanger in a water-source heat pump on an open ground loop?
Thanks,
-Vince
I'm wondering if anyone has had long-time experience with stainless steel exchangers on open-loop geothermal systems.
The reason I am asking is because the heat pumps with stainless steel exchangers are slightly less expensive (and more readily available where I am) than cupro-nickel exchangers.
So to re-iterate: is it OK to use a stainless steel exchanger in a water-source heat pump on an open ground loop?
Thanks,
-Vince





RE: Stainless steel vs. cupro-nickel exchangers
Patricia Lougheed
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RE: Stainless steel vs. cupro-nickel exchangers
RE: Stainless steel vs. cupro-nickel exchangers
Patricia Lougheed
Please see FAQ731-376: Eng-Tips.com Forum Policies: Eng-Tips.com Forum Policies for tips on how to make the best use of the Eng-Tips Forums.
RE: Stainless steel vs. cupro-nickel exchangers
Usually air-side heat transfer characteristics of fin-and-tube heat exchangers are determined from limited experimental data. But the overall heat transfer coefficient Uh is proportional to the tube and fin thermal conductivity. Changing the materials to a less conductive alloy will affect the system performance.
Stainless steel 316 (most commom HE) can exhibit stress corrosion cracking above about 60°C and is considered resistant to potable water with up to about 1000mg/L chlorides at ambient temperatures, reducing to about 500mg/L at 60°C.
RE: Stainless steel vs. cupro-nickel exchangers
So basically if the well water doesn't go above 45 F (7.2 C) year-round and the chlorides stay below 1000mg/L I will be fine with Stainless steel?
Makes sense.
-Vincent
RE: Stainless steel vs. cupro-nickel exchangers
RE: Stainless steel vs. cupro-nickel exchangers
It's money well spent.
Copper nickle systems are good at chloride resistance, but you better not have any traces of ammonia in the system.
Be specific with your materials ......
Which particular cupro-nickle alloy are you considering ?
What is the temperature range of service ????
-MJC
RE: Stainless steel vs. cupro-nickel exchangers
rmw