Abstract: A water cooling control for a building structure includes a temperature sensor device and a zone controller. The temperature sensor is adapted for detecting a temperature difference of the water at each of the end loop terminals of the duct system for determining the amount of heat removed from the respective heat exchanger in responsive to heat exchange of the water. The zone controller is operatively linking with the temperature sensor device for adjustably regulating a flow rate of the water through a control valve of the delivering device in responsive to said temperature difference at each thermal zone until the water is maintained at the optimum flow rate to ensure the respective heat exchanger being operated at an optimum condition while being energy efficient.