Then you'll need to draw up a design spec that will take into account variables such as, for example:
The layout of the building in terms of internal walls and corridors if it's not open plan
The amount and size of furniture in there
The number of people working on an average day
The thermal barrier rating of the walls and ceilings and how well they keep out the heat from outside
The number of exterior openings, (windows and doors) and if door are automatically opened/closed when a person goes through them
The availability of false ceiling space for the ducting needed to fulfill the airflow needs of the AC system
You'll also need to know a number of associated facts about the building that might have an impact on the cooling system's efficiency.
Commercial air conditioning workhorses will need to feature industry-leading products from some of the most respected brands in the business.
It pays to shop around for not just the best deal on AC equipment, but to make sure the equipment you'll end up spending your company's money on is good quality, reliable, effective and solidly backed up by after-sales service and on-going maintenance and repair contracts from an air conditioning company that delivers quickly and without any fuss.
There are different configurations that best suit certain circumstances, such as central HVAC systems to control everything from a central point, distributed zone systems with industrial size mini-split equipment and even large industrial size portable units that can handle surprisingly large areas.
Commercial Portable Air Conditioners
While I'm on that subject, I came across one American-based AC company that manufactures and sells high quality US-made portable units for industrial deployment called Kwikool.
They really do make some of the best, most robust, high quality industrial air conditioning units in the business. There is a really good review of some of the Kwikool heavy-duty cooling devices as well as factors governing commercial air conditioning here:
https://airconergy.com/air-conditioning/commercial-portable-air-conditioners.php
I'll be adding more information on this subject as my researches go deeper into it.