Desiccant-based gas-fired cooling systems are a potentially attractive method for conventional residential and commercial space conditioning and dehumidification. This work focuses on state-of-the-art solid-based desiccant cooling systems. The operating principles and components of such systems are described and the importance of each discussed. Several operating configurations, or modes, are presented, and sample applications for each are given. Annual performance simulations were made to evaluate the potential of desiccant cooling systems for economical space conditioning. The effects of application type, climate, and operating mode were studied. Results of the simulations are presented in the form of cooling load met, gas consumption, and coefficient of performance (COP). Annual COPs for all the simulations are higher than ARI design performance and show potential for economical space conditioning. The results also indicate that applications with larger requirements for fresh air, either in the form of ventilation or makeup air, have the highest COPs and, therefore, have the most promise for initial market penetration.Units: Dual