In a solar water heater, energy from the Sun is gathered by rooftop collectors, which circulate water through tubes in the collector. The solar radiation enters the collector through a transparent cover and warms the water in the tubes. Assuming that 80% of the incident solar energy gets lost (i.e; it does not go into heating the water), what collector area is necessary to take water from a 200-L tank and raise its temperature from 20 C to 40 C in 1.0 h? The intensity of incident sunlight is 700 W/m^2.
Q = mcdelta t
delta t = iR