We received a specification for a vacuum unit of an Air Cooled Surface Condenser, one of the operating conditions is :"HEI DESIGN CONDITIONS", please can one advise this demand?
I am not familiar with their topics that address air cooled condensers. However, my recollection of the earlier version that was available in 2003 is that it does not adequately afford a conservative design in the case where there is a large steam bypass system discharging into the condenser.
I haven't seen this spec for many years. However, one aspect of it was that a certain amount of air leakage into the system had to be accounted for in the design of a condenser. My memory tells me that the result was a 80/20 mol fraction mixture of steam and air at the outlet, thus reducing the condensing temperature at that point.
Whether you use steam jets or liquid ring vacuum pumps, you should choose a manufacturer that adheres to these design standards.
Their publications are not free, however.
rmw
PS: the maximum vacuum possible in a steam condenser is a function of the hotwell condensate temperature (which, of course is a function of approach to the cooling water - or air - temperature.)