Calculations on performance characteristics of counterflow reversibly used cooling towers

This paper aims at developing an analytical model for the coupled heat and mass transfer processes in a counterflow Reversibly Used Cooling Tower (RUCT) based on operating conditions, which is more realistic than most conventionally adopted Merkel approximations. Temperature and moisture content differences are chosen as the driving forces of heat and mass transfer correspondingly and a system of specific difference equations is developed to solve the model more efficiently. The model is investigated by using an iterative algorithm, which is validated with the experimental data reported. The analytical model also accommodates the direct and quick calculation of air and water temperature profiles, moisture content of air and the water mass flow rate change along the vertical length of the RUCT. With the aid of the developed model, the thermal behavior of the counterflow RUCT under various operating and environmental conditions is also studied in this paper. The results reveal that the proposed model can provide a theoretical foundation for practical design and performance evaluation of counterflow RUCT.

► A mathematical model of a RUCT under counterflow conditions for the steady-state operation has been presented.
► The proposed model of RUCT was validated with the experimental data reported.
► Air and water states at any sections inside the RUCT can be determined.
► The proposed analytical model can provide the theoretical foundation for practical design and performance evaluation of counterflow RUCT.