Study of heat and mass transfer in a vertical-tube evaporative cooler

Evaporative coolers are three-fluid heat exchangers employed for heat rejection to the environment. A mixture of air and recirculating water is used as the cooling medium. These coolers are considered viable routes for improving thermal efficiencies of power-generating and refrigeration cycles. The heat- and mass-transfer processes taking place in a vertical-tube evaporative cooler are studied. A steady-state, one dimensional model of cooler performance is formulated. This model is validated by experimental measurements, taken in a single-tube exchanger, of the controlling heat- and mass-transfer coefficients. These coefficients occur at the air-water interface. Heat fluxes and enhancement ratios for conditions of interest are measured and calculated, and the results are compared and discussed. The model is found to adequately predict heat-exchanger performance.