If you try to make the calendar function in Excel or any other Windows based program work, you will spend a lot of time. Also, you might run into the problem that Microsoft changes the ActiceX module and your code doesn't work in one year. This happen to me using calendar Active X in MS Access...
I'm looking for formulas/spreadsheets to assist me with calculating the required opening in an enclosed guard that has HEPA filters on the top. We typically exhaust to the shop floor at a slight positive pressure within the enclosure to keep particles (dirty air) out of the "clean" mini...
Many cylinder manufacturers provide free software that can be used to calculate speed, flow, etc.
Check out FESTO ProPneu software. Maybe you can adapt their software to your problem.
http://www.festo.com/INetDomino/coorp_sites/en/61d22ceb41391b1ac1256b41003afdaf.htm