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Unformatted text preview: 4.42 Quiz 1 An inventor proposes a refrigerator that makes ice which is then melted and used to cool a cold storage room. The refrigerator is put into a closed insulated room without any air flow into or out of the room. It is turned on when the water is liquid at 0C, the initial room temperature. It makes 10kg of ice which is then melted to liquid at 0C without any evaporation of the water. a) Will the room temperature increase or decrease for the entire process (from the time the refrigerator is turned on to the time the ice has melted)? b) If the refrigerator has a COP of 3 and it is only used to make the ice, how much electrical energy does the refrigerator require? Take the internal energy change from ice to liquid water at 0C as 334 kJ/kg. The COP is the rate of useful cooling to the rate of electrical energy consumed. c) If 0.25 kg of water evaporates after all of the ice has melted, does the room temperature increase or decrease over the entire process? room temperature increase or decrease over the entire process?...
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This note was uploaded on 11/29/2011 for the course CIVIL 1.018j taught by Professor Markusbuehler during the Fall '08 term at MIT.
- Fall '08