Three kilograms of liquid water at 0° C is put into the freezer compartment of a Carnot refrigerator. The temperature of the compartment is -13.5° C, and the temperature of the kitchen is 24.5° C. If the cost of electrical energy is ten cents per kilowatt · hour, how much does it cost to make two kilograms of ice at 0° C?
COP= Qc/W , Qc/Qh=TL/Th , Q=mL L=3.35 x 10^5 j/kg , Qh= W+ Qc, 3,600,000 = 1 kilowatt hour
The Attempt at a Solution
I used the formula Q=mL to solve for Qc, because this is the heat that needs to be moved to the hot reservoir, got an answer of Qc=1005000J. I then used Qc/Qh = TL/Th to solve for Qh came out to be 1149885.584j. I then used the Qh=W+Qc to solve for W, which equaled 144885.584j. I then solved for the COP = 6.937. I did convert temp values to K. I'm lost after this point I need to know how to come up with the cost.