In a small IT room, approx 17w x 17d x 10h, running 5-6 servers, 8-9 UPS, and 3/4 full rack of networking equipment, the temperature ranges from 70 degrees to 88 degrees. There is no main building AC overnight or on weekends, so temps peak at those times.
We have three separate portable AC floor units in the room, all venting into the walls/drop ceiling (no windows or exterior access): 12,000 BTU, 12,000 BTU, 14,000 BTU (38,000 total - or is some lost from three separate units).
I ran a simple estimation calculator (without entering specific wattage of all devices) and came to approx. 28,000 BTU needed for a room that size with those machines/batteries.
The three AC units are positioned in 3 corners of the room at varied heights (floor to ceiling - on shelving) and are aimed in varied locations. Adding on the second AC unit maybe brought the average down 5-6 degrees, the third AC unit only 2-3 degrees. Never dropping below 70 degrees, the AC units have run 100% of the time since they day they were installed. Our oldest unit occasionally only blows out warm air now - due to old refrigerant? (approx 4 years)
Any thoughts on what could be wrong? Air flow? Venting? Ideally I could keep the room at low 70's 24/7.