Mathematical modeling and study on the application of cross flow direct evaporative cooler under different indoor and outdoor environmental conditions

摘要

Performance of a cross flow direct evaporative cooler under different indoor and outdoor conditions was investigated by a thermodynamic model and using finite difference scheme. Unlike the previous studies, the temperature variation of water film during the evaporation process was included among the modeling, and the error of the mathematical model to estimate the effectiveness of the cooler became lower than the error reported in the literature. To achieve the comprehensive results and evaluation of the applicability of the system under real conditions, the performance of the cooler in ambient temperatures of 25, 30, 35 and 40 °C, relative humidities of 10, 30, 50 and 70% and cooling demand of 1-5 kW for a building with air changes of 5, 10 and 15 per hour was investigated. Lastly, the study on the performance of the cooler in different Iranian provincial capitals showed that for air change of 15 per hour and cooling demand of 1 kW, the system could provide thermal comfort conditions in 24 provincial centers while for air change of 5 per hour and cooling load of 5 kW, this goal cannot be achieved in any centers. Moreover, comparing the water consumption of the coolers showed that the maximum and minimum daily water consumption was for Yazd in September and for Kermanshah on July, respectively. Investigation of the coefficient of performance of the system for air changes of 10 and 15 per hour revealed that Khoramabad and Bandar Abbas had the maximum and minimum coefficients of performance, respectively.