Do you know any surgeons that want to run the OR colder?
Thought so.
With 20 air changes per hour in ORs, colder is easy. In humid conditions, though, colder temperatures mean higher humidity. The classic solution is subcooling - taking the supply air temperature lower to wring out humidity. We used to do this with DX coils and condensing units, but now mostly do that with a dedicated chiller, usually air-cooled, often with some glycol to allow low-temp operation and protect it from freezing. (For those of you in Southern CA, "freezing" is a theoretical condition where the air temperature dips below 32F. Crazy, I know.)
The reality of OR air systems is that outside air is the primary source of moisture. In the classic system, we mix moist air with dry return air, then subcool that air to dehumidify, then have to reheat to keep from overcooling the OR. Wasteful, both on cooling and reheat energy.
The first improvement is to dehumidify the outside air separately - before mixing with return air. Two benefits - lower cooling load of course, but also a lower reheat load. When we mix 20% cold dry air with 80% return air, we get a mixed air temperature that needs less reheat - and we can cool it a bit (sensible only) if we need a lower temp.
But even better is to do the dehumidification with an active desiccant. Again - this is only the outside air stream. In most cases, that means just 20-25% of the air. Desiccants allow us to dehumidify without subcooling, so we don't need a separate chiller system. Desiccants do need heat to drive off moisture, but that can be done with energy recovered from the exhaust stream. Add some additional cooling at the AHU, and we have cool, dry air going to the ORs - at a much lower energy cost than the old ways.