Dear Sir,

In our project there is specified a closed expansion tank for the chilled water system, but our contractor wanted to change to the bladder type expansion tank. Please advise, if it is suitable to serve the purpose. Also he says that the specified tank is a plain steel tank, which are old type of expansion tank with a capacity of 20,000 Gallons.

The reason for this change is space saving, tank volume, energy saving and low maintenance according to him.

Awaiting your kind reply
Mohammed Ashfaque
Mechanical Engineer

With a tank of that enormous size, I suggest you first tell here what the size and the specifics are of the project itself.
Just for your information have a look at an article on the pro's and con's of different expansion tanks : Expansion Tanks 101: the facts and myths (http://contractormag.com/hydronics/cm_column_75/)

I'll check back here later !

:)