In solar-heated buildings, energy is often stored as sensible heat in rocks, concrete, or water during the day for use at night. To minimize the storage space, it is desirable to use a material that can store a large amount of heat while experiencing a small temperature change. A large amount of heat can be stored essentially at constant temperature during a phase change process, and thus materials that change phase at about room temperature are very suitable for this purpose. Determine how much heat (kJ) can be stored in a 5-mo storage space using water with a heat capacity of 4.00 kJ/kg-°C and a temperature change of 20°C. 400,000-------O 626,400----O 1,645,000------O 42,200

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