Concrete core cooling system is an energy efficient alternative to the conventional mechanical cooling system. It provides better comfort due to direct absorption of radiation load, low indoor air velocity, apt vertical temperature gradient and absence of noise. It can be operated at relatively higher water temperature, which facilitates the use of passive cooling strategies. In this study, a cooling tower, which is an 'evaporative cooling system', is preferred over other passive cooling options due to its better cooling performance in dry regions and its ability to operate all through the day. This paper presents the results of computational fluid dynamic analysis of a room cooled by concrete core cooling system supported by a cooling tower. The study reveals that for a typical hot-semiarid summer climatic condition in India, the system reduces the average indoor air temperature to a comfortable range of 23.5 to 28., from an uncomfortable range of 35.3 to 41., in a building without cooling. The average predicted percentage of dissatisfied falls from 99.7% in a building without cooling, to 37.3% if roof and floor of a building are cooled with concrete core cooling system and further to 6.3% if all surfaces are cooled with concrete core cooling system. © International Society of the Built Environment.