I’ve used portable air conditioners in situations like this
From RECHIL !
Mechanical cooling equipment consumes the vast majority of power used in small to mid sized data centers. By improving the cooling efficiency when initiating a plan to reduce costs noting but airflow management and cooling tuning are primarily one-time costs. On 3 racks, make sure that they have active airflow system.
The main key factors include Summed Rated Cooling Capacity (CCF), total IT load, and identification of hot spots. Once u have this information, definitely, u may determine the cooling capacity factors. The data helps to determine, how much room there is for improvement, how is it cost effective, & how much the environment can be improved.
You can go through here and also here.