When determining a cooling strategy, data center designers and operators face many decision points regarding the cost of owning and operating their cooling equipment. In financial terms, these decisions usually involve tradeoffs between lowering the initial capital expenditure (CAPEX) or minimizing operating and maintenance costs (O&M), which include utility costs. CAPEX, O&M, and energy costs all combine into total cost of ownership (TCO).
There are several technical issues involved in cooling equipment selection and sizing. Calculations about heat load, chilled water temperatures, ambient conditions, and other factors are all involved. What follows, however, is a broader view of the important economic decision points regarding two basic chiller categories: water-cooled centrifugal chillers and air-cooled scroll and screw chillers.