Abstract In this study, the effects of control strategies of night-purge control system on control characteristics andenergy consumption for central cooling system in building are researched by simulation. The start time and set-pointtemperature for night-purge control with outdoor temperature changes and building cold storage performance are obtained. The system analysis modelling is done by using TRNSYS program package, and the control performanceswith suggested night-purge control method are compared with the existing control ones. As a result, the suggestednight-purge control method shows maximum 16.8% and 28.6% energy saving in comparison with existing control method and conventional one without night-purge control, respectively. Keywords : Central cooling system, Night-purge control, Set temperatures, Outdoor air cooling, Outdoor air temperature * Corresponding Author : Byung-Cheon Ahn(Gachon University) Tel: +82-31-750-5309 email: bcahn@gachon.ac.kr Received August 18, 2015 Revised (1st September 17, 2015, 2nd October 7, 2015)Accepted October 8, 2015 Published October 31, 2015