Development of a simulation tool for calculating maximum allowable cooling time in closed type cooling tower

In winter, when the external air temperature is below zero, there is a risk of damage to coils in a closed type cooling tower due to freezing of cooling water. In warm climates, a method of draining cooling water from the coil can not be adopted to prevent freezing because a cooling load exists even in winter. It is necessary to make warm water circulate through the coil in closed type cooling tower. In this case, it isn’t clear when to operate an electric heater and a circulating warm water pump. The authors developed a simulation tool to calculate the maximum allowable cooling time in a closed type cooling tower taking into account the pressure increase due to freezing of cooling water and the allowable elastic deformation. Based on the calculated maximum allowable cooling time, an optimal operational method for frost prevention can be determined.