Analyses the design process for the natural cooling cycle and establishes criteria for the relative usefulness of various natural cooling options. Defines the natural cooling cycle as any chilled water system for which the cooling effect is achieved solely in the cooling tower. Reports the application of a program developed to determine energy consumption for various natural cooling system options to compares these options and select an optimal design. Various methods of condensing the input to the systems' evaluation were tested and compared with results of an hourly evaluation. The average day method was used in the system evaluation programme to test the effect of varying building design parameters on the design for natural cooling. Established five design criteria in the analysis.KEYWORDS: Cooling towers, designing, buildings, chilled water supply, computer programs, energy consumption