Solar Houses Use a Variety of Energy Storage Devices to Retain

Multiple Choice

Solar houses use a variety of energy storage devices to retain the heat absorbed during the day so that it can be released during the night. Suppose that you were to use a device of this kind to produce steam at 100°C during the day, and then allow the steam to cool to 0°C and freeze during the night. How many kilograms of water would be needed to store 20.0 kW-hours of energy in this way? The latent heat of vaporization of water is 22.6 × 10⁵ J/kg and the latent heat of fusion of water is 33.5 × 10⁴ J/kg.

A) 12.4 kg
B) 23.9 kg
C) 35.7 kg
D) 42.6 kg
E) 54.2 kg