In With The New; Out With The Old
Systems compared — A conventional system brings in the maximum amount of outside air, whether needed or not. No allowances are made for crowd size. The cooling unit functions as an air handler even if CO2 levels are extremely low.
In a split system, the cooling unit only recirculates air inside the building. Human respirations increase the buildings CO2 levels and trigger the CO2 sensor to turn on the outside air intake system. So this ventilation system only brings fresh air into the building as needed, depending on crowd size. This dramatically lessens energy consumption and cost.