Air-cooled or water-cooled: what changes in Gulf conditions
The textbook comparison shifts once you account for high ambient temperatures, dust and the cost of water.
The standard comparison says water-cooled plant is more efficient and air-cooled plant is simpler. Both remain true here, but the margins change enough to be worth restating.
Air-cooled
Heat is rejected straight to ambient air. No tower, no condenser water pumps, no water treatment, and a much smaller plant room. The trade-off is that performance is tied to ambient temperature, and ambient here spends months at a level that pushes condensing pressure up and efficiency down. Dust makes it worse, because the coil is exposed and fouls steadily.
It suits smaller loads, retrofits, sites where plant space is scarce, and buildings where simplicity of maintenance outweighs running cost.
Water-cooled
Heat is rejected through a condenser water circuit to a cooling tower, which uses evaporation. Condensing temperature is lower and more stable, so efficiency is better and less sensitive to a hot afternoon.
The cost is a second system to own: tower, condenser water pumps, water treatment, and the maintenance discipline all of that requires. Water consumption is a real operating cost in this region, and towers carry a water hygiene obligation that has to be managed properly rather than nominally.
How the decision usually resolves
Load size and hours of operation dominate. A large load running long hours will usually justify water-cooled on running cost alone. A smaller or intermittent load rarely recovers the extra capital and maintenance burden. Between those, plant space and the availability of someone to look after a tower properly tend to decide it.
Whichever is chosen, the maintenance regime is different in kind, not just degree — and the contract should reflect that.