A research team is evaluating materials for passive thermal energy storage on a rooftop
PHYSICS · Multi-part · GCSE · Physics · Energy · Energy
Problem
A research team is evaluating materials for passive thermal energy storage on a rooftop. A 15.0 kg block of granite (specific heat capacity 0.79 kJ kg−1 °C−1) and 15.0 kg of liquid water (specific heat capacity 4.18 kJ kg−1 °C−1) are both placed outside at sunrise with identical initial temperatures of 18.0 °C. Over the course of the day, each material absorbs 1.50 MJ of solar energy. However, the water also loses 0.30 MJ of energy through evaporation, while the granite experiences negligible energy loss.
(a) Determine the final temperature of the granite at sunset.
(b) Determine the final temperature of the water at sunset, accounting for the energy lost to evaporation.
(c) By how many degrees Celsius does the granite’s final temperature exceed that of the water?
(d) Based on your calculations, evaluate which material is more effective for storing thermal energy during the day for release at night. Justify your answer with reference to the quantitative results and relevant physical properties.