The part-load performance of a single-zone, simple air-conditioning system was simulated using various control strategies. A new coil model for cooling and heating was employed as a component in the overall system with either single-phase (chilled or hot water coil) or two-phase (DX or steam coil) fluid through the tubes. In this analysis the varying operating conditions of the overall heating, ventilating, and air-conditioning (HVAC) system were studied as the load in the space changed. Some of the control strategies considered were chilled or hot water bypass, return or mixed air bypass, and variableair- volume (VAV) flow with reheat. Attention was focused primarily on space comfort requirements and the loads at the coil and plant. The effect of various coil parameters on the overall HVAC system performance was also studied.