A modular chiller system includes a switching and pumping module, one or more drycooler modules, and one or more chiller modules. The switching and pumping module, the one or more drycooler modules, and the one or more chiller modules share same water, power, and signal interfaces. The cooling capacity of the modular chiller system may be increased by adding drycooler modules or chiller modules without additional hydraulic and electrical infrastructures.