I have to cool an area of 20X15X6 meter, having false ceiling at a depth of 500mm from real ceiling.The AC Plant room is an adjacent room of size 5X15X6 Meter. The airconditioning is to be done through supply air ducts and return through false ceiling plenum.occupancy 50 persons.
1) Airconditioning load.
2) Duct Size.
3) CFM required.
4) Supply air grill area.
5) Return area size.
6) No.of air changes required.

Are you going to try this with 1 unit or 2? The actually ceiling hight is going to be close to 20' ? Looks like you may be close to 14 tons. What type of inslulation? Any windows? Are there any outside walls or all interier? Computers, or other heat source besides the 50 people?

How to calculation CFM in Airhandling unit??

How to calcultlion of CFM with CFM Meeter in Air handling unit??