The Desert Solar Still · AI Generator #GEN-CCA09ECE
Physics · thermodynamics
Problem
A solar still is a simple device used to purify water in desert regions. It consists of a shallow black pan containing impure water, covered by a slanted transparent glass cover. Solar radiation heats the water, causing evaporation. The water vapor condenses on the cooler inner surface of the glass and drips into a collection channel.
In a particular solar still, the black pan absorbs solar energy at a rate of P=150W. Under steady-state conditions, the pan maintains a constant temperature of Th=60°C while the glass cover remains at Tc=30°C due to air cooling. Heat is lost from the system to the environment at a rate of Ploss=90W.
What is the maximum theoretical rate of water evaporation (in grams per hour) if the process operated as a reversible heat engine extracting work, with the remaining energy used for evaporation? The latent heat of vaporization of water is Lv=2260J/g.