An important parameter that affects the performance of open-cycle desiccant cooling systems is the shape of the desiccant adsorption isotherm. Relationships between the desiccant matrix heat capacity, the heat and mass transfer resistance, and the isotherm shape will also influence desiccant cooling system performance. These relationships are quantified by computer simulation. Results showed that Type 1 isotherms are less sensitive to the presence of heat capacity than linear or mild Type 2 isotherms. Also, the effects of heat and mass transfer resistance are essentially the same regardless of isotherm shape.