Gas District Cooling (GDC) provides electricity and chilled water to facilities with relatively low running cost and has the potential to reduce CO2 emission as it can make effective use of wasted energy. However, the present CO2 emission tends to be higher than expected due to the chilled water supply-demand gap. To efficiently manage the gap, this paper introduces a novel chilled water supply-demand gap model and proposes an integrated GDC and Data Center (DC) control based on the model. The gap model, defined by GDC plant and DC controllable parameters, estimates the required additional chilled water supply. Then, DC and chillers in the plant are controlled based on the model to minimize the required additional supply. The analysis using GDC operational data in Universiti Teknologi PETRONAS shows that the accuracy of the models depends on temperature differences between rooms and outdoor, Steam Absorption Chillers (SAC) operations and the target period of the models. Thus, the analysis suggests that GDC with room and outdoor temperature sensors, SAC operation scheduling, and thermal storage tank (TES) can improve accuracy of the model and optimize the GDC operations more accurately to reduce CO2 emission. © 2013 IEEE.