Variation of Water Temperature along the Direction of Flow: Effect on Performance of an Evaporative Cooler

This paper presents a model for the evaluation of the variation of the water temperature along the direction of flow in an evaporating pad. The model has been used to evaluate the mean air exit temperature and the transient temperature of the water in the tank. The analytical results are in agreement with the observations in our experiments. The time variation of the temperature of water in the tank has been investigated and the new concept of using the tank water for cooling have been investigated theoretically and experimentally; the theory is in good agreement with experiment. It is seen that the penalty on the mean exit air temperature is negligible for thermal loads QE™ (for cooling) of the order of 1 kW; it is seen that it is 0.6 °C for QE™ = 2 kW. Further it is concluded that for typical coolers the steady state temperature of water in the tank is reached in a time of the order of one hour or less.