I am a little confused about your real name......is it "Bob" or "John" or perhaps something different ??? As the self acknowledged experts in the field, you somehow seem to offer very little in terms of an answer to the original question about tube materials..... Like i said above, Yuba, is simply just a place to start....there are lots of other places that you could start. Yuba has fabricated and produced many steam surface condensers For tube material recommendations for the small condenser that is in consideration by the original post, one could ALSO start with Graham Manufacturing in upstate NY http://www.graham-mfg.com/scadv4.html (or Foster Wheeler or several other vendors ) It was my understanding that the purpose of an engineering forum was to post and answer questions......If a reference to a website is useful to the answer then it should be mentioned..... My opinion only MJC

I hope this doesn't come too late to benefit the original poster, but it seems that no one actually answered the question asked. Admiralty brass has a heat transfer coefficient of 64 Bth/hr-ft-°F while austenitic stainless steels average 9.3 using english units. But that doesn't automatically rule out the tubing metallurgy change that "bob" wants to make. Because the modulus of elasticity of austenitics are in the range of 29Kpsi as compared to brass's 16, a thinner tube wall can be used in the subsitute stainless tubing, offsetting the heat transfer penalty of the SS tubing. One must go through the vibration calculations to determine the minimum wall thickness required of the tubing which will be determined by the existing tube support spacing in the condenser. If it is necessary to get a wall thickness thin enough to counteract the different heat transfer characteristics of the tubing, the tube bundles can be "staked" where strips of plastic or metal are inserted mid-span into the tube rows between support spacers. Then all one has to do to accomplish this is look at the weak points of austenitic tubing with regard to what attacks them (they don't like chlorides, bio-fouling can be an issue to name a couple) and see if the tubing is compatable with the cooling water. Plus, going to a thinner wall will result in higher cooling water flows due to lower pressure loss across the condenser, (a contributor to the offset of the different HTC's) so the capacity of the pumping system to accomodate this higher flow has to be carefully checked. Anecdotally, it was once suggested at a large utility station out of frustration with some issues with the existing 22 ga. 304 SS tubing with respect to fouling issues that the condenser be retubed in Admiralty. The plant people thought the gain in HTC would overcome some of their performance losses due to fouling of the SS tubes. I was shocked upon running the numbers for their condenser using a HEI software. I expected to see the gain that they anticipated, although I was not enthusiastic about brass tubing in their (dirty river) water. Because of the need to go to 18 ga brass tubing to prevent vibration problems with the existing tube support spacing, between the heat transfer resistance of the thicker wall of the brass and the reduction in CW flow due to the reduced flow area, there was a significant performance loss in this condenser. One other consideration would be the compatability of a harder tube material being rolled into the (assumed) original soft metal tube sheets; not impossible, but requires care, and the galvanic couple created by the more noble SS tubes in a soft metal tube sheet and/or less noble waterboxes. Other than that, go for it Bob. rmw