Problem 7: On a hot day, the freezers in a particular ice cream shop maintain an average temperature of Tc = -11° C while the temperature of the surroundings is Th = 27° C. Randomized VariablesTc = -11° C Th = 27° C Part (a) Calculate the maximum coefficient of performance COP for the freezers. Part (b) If the work input to the freezer is W = 2.65 kJ and the freezer actually removes Qc = 7.8 × 103 J from the ice cream each second, what is the real coefficient of performance? Part (c) An employee puts m = 1.65 kg of melted ice cream at T0 = 3.5° C into the freezer. Assuming that the ice cream freezes at T1 = -1.0° C, how long in seconds will it take for the ice cream to reach its freezing temperature? Take the specific heat capacity of the melted ice cream as c = 4,000.0 J/(kg⋅K). Part (d) Assuming a latent heat of fusion of Lf = 280 kJ/kg, how long, Δt2, in seconds does it take to freeze the ice cream?
Problem 7: On a hot day, the freezers in a particular ice cream shop maintain an average temperature of Tc = -11° C while the temperature of the surroundings is Th = 27° C.
Randomized VariablesTc = -11° C
Th = 27° C
Part (a) Calculate the maximum coefficient of performance COP for the freezers.
Part (b) If the work input to the freezer is W = 2.65 kJ and the freezer actually removes Qc = 7.8 × 103 J from the ice cream each second, what is the real coefficient of performance?
Part (c) An employee puts m = 1.65 kg of melted ice cream at T0 = 3.5° C into the freezer. Assuming that the ice cream freezes at T1 = -1.0° C, how long in seconds will it take for the ice cream to reach its freezing temperature? Take the specific heat capacity of the melted ice cream as c = 4,000.0 J/(kg⋅K).
Part (d) Assuming a latent heat of fusion of Lf = 280 kJ/kg, how long, Δt2, in seconds does it take to freeze the ice cream?
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