• # question_answer Water in an insulated evaporative cooler evaporates at the rate of 0.003 kg/s. Air flow rate is 1 kg/s. What is the air temperature decrease if the specific heat of humid air is 1 kJ/kg. K and latent heat of water is 2500 kJ/kg? A) $2.5{}^\circ C$                       B) $3.0{}^\circ C$C) $7.5{}^\circ C$                       D) $10{}^\circ C$

${{m}_{w}}=0.003\,kg/s,\,{{m}_{a}}=1\,kg/s,$ ${{c}_{pa}}\,\,=\,\,1kJ/kg.K,\,{{h}_{fg}}\,\,=\,\,2500kJ/kg,$ ${{m}_{a}}\times {{c}_{pa}}\times \Delta t={{m}_{w}}\times {{h}_{fg}}$ $1\times 1\times \Delta t=0.003\times 2500$ $\Delta t=7.5{}^\circ C$