Airborne or waterborne cooling?
Both air and water can be used for distributing cooling. What makes water the ideal choice for cooling is that waterborne systems take up less space, the unit itself is smaller, and water is a more effective medium for energy transport than air. Conversely, if you opt for airborne distribution, the benefit is less complex, lower-cost installation, a system that can handle larger air volumes, and the option of using free cooling.
In sum, there are consequently a number of factors determining which basic system to opt for. The cost, aesthetic and practical considerations all need to be factored in, as does the building space available.