Desiccant cooling systems regenerated at high temperatures by a natural gas source are a high-performance alternative to vapour-compression cooling systems. The performance of a gas-fired cooling system operating in the recirculation mode is optimised by modelling, using different desiccant materials. Design and operating parameters investigated include the fraction of the wheel that is heated in regeneration, termed the "staged regeneration fraction," the regeneration temperature, the sorption time (inversely proportional to wheel rpm), and desiccant moisture uptake. Performance results documented include the optimum system coefficient of performance (COP) and cooling capacity along with operating conditions, staged regeneration fraction, and sorption time corresponding to the optimum. The performance of the system operating in the recirculating mode is also compared to the performance of an optimally designed system operating in the ventilation mode.KEYWORDS: calculating, gas fired, desiccants, cooling, air conditioning, evaporative coolers, performance, natural gas, absorptivity, coefficient of performance, comparing, ventilation, moisture, optimisation