Chapter 12, Problem 12.145P

A wet towel hangs on a clothes line under conditions for which one surface receives solar irradiation of $G_s={\text{ 900 W/m}}^2$ and both surfaces are exposed to atmospheric (sky) and ground radiation of $G_{atm}={\text{ 200 W/m}}^2{\text{ and G}}_g{\text{=250 W/m}}^2$ , respectively. Under moderately windy conditions, airflow at a temperature of ${27}^{\circ }C$ and a relative humidity of 60% maintains a convection heat transfer coefficient of ${\text{20 W/m}}^2\cdot \text{K}$ at both surfaces. The wet towel has an emissivity of 0.96 and a solar absorptivity of 0.65. As a first approximation the properties of the atmospheric air may be evaluated at a temperature of 300 K

Determine the temperature $T_s$ of the towel. What is the corresponding evaporation rate for a towel that is 0.75 m wide by 1.50 m long?