The central cooling plant is a critical component of any building or facility. As with all mechanical equipment, there is a finite useful life for the equipment. The major component is the chiller, however the cooling tower also deserves specific consideration. Technology changes are another big reason for re-engineering the central plant. Absorption chillers, especially double-effect, offer a good option for utility rate structures with high peak period demand or usage charges or rate schedules with ratchet clauses for the demand charges. Engine-driven chillers provide an alternative to absorption chillers when a natural gas cooling is desired. Primary-secondary chilled water distribution systems were developed to allow constant flow through chillers, required by the chiller manufacturers, with variable flow for the load side of the system to improve efficiency. Development of the commissioning plan must proceed with the design and construction phases, especially since it is likely that completion of the project will occur in stages over time.