Hello Fayaz!
Let me suggest you this kind of approach:
1. You have to know the mean temperature and humidity reference values: Those are your "set/nominal-points". You can find those at various sources, as the named before or at some recent ASHRAE manual.
2. About the place you want to treat, to do air-conditionning:
- the dimensions of the place?;
- the climate conditions along the year?;
- how much paper you want to storage there?
- Thermal loads ?
- how is its distribution in the space in order to apply the most appropriate air-diffusion model?
3. In order to design/calculate your installation, that means to define which equipment is the more suitable/economic for you case:
- Chiller and air handling-unit with ducts?
- How much fresh air?
- Thermostatic or enthalpic control?
- The same approach with roof-top unit?
- Recovery energy devices to consider?
Notice 1: These last ones depends on the flow-rates and power magnitudes you have, partial/global pay-back analysis, and so on, so on...
- And very important: you need how "to read" the building, the space in order to design the most efficient/cheap installation to fulfill the effects your Client wants, looking for!
Finally. try to get some advice from some one more experienced in the field.
(Notice 2: Air-conditionning is complex, but it is not difficult it needs rather (and always!), some good-sense=experience. Each case, is a case!)
Hope this can help!
zzzo