The amount of heat generated is known as the heat gain or heat load. Heat is measured in either British Thermal Units (BTU) or Kilowatts (KW). 1KW is equivalent to 3412BTUs.
The heat load depends on a number of factors, by taking into account those that apply in your circumstances and adding them together a reasonably accurate measure of the total heat can be calculated.
Factors include: The floor area of the room
If your room has no windows, you can ignore this part of the calculation. If, however there are windows you need to take the size and orientation into account.
You will have to take that into account people who normally working in the space.
Clearly most heat in a room is generated by the equipment.
The amount of cooling required depends on the area of the room.