Question

3 1243 WATCH FOR ICE UT's Civil and Environmental Engineering department is considering the purchase of an ice machine. Samantha Allen, business manager extraordinaire, wants help in evalulating the purchase. She knows that the inside of the machine is -13 °C and the outside temperature is 30 °C, The initial temperature of the water is 22 °C, and the coefficient of performance is 31% of the ideal. Electrical energy costs $0.13 /kW-hr. The specific heat of ice is 0.5cal/g-oC EXAMPLE DISCUSS NOTES IMAGES STATS HELP UNITS Part History Description Answer Chk What is the cost ($) of electricity to make 8 five pound bags of ice? 10 pts.110% # tries: 0 Show Details А. 2% try penalty Hints: 0,2 If the motor that drives the compressor consumes 950 W of electricity, how long does it take to make 8 bags of ice? (include units with answer) 10 pts, 110% tries: 0 Show Details |В. Format Check 2% try penalty Hints: 0,0

Civil and Environmental Engineering department is considering the purchase of an ice machine. Samantha Allen, business manager extraordinaire, wants help in evalulating the purchase. She knows that the inside of the machine is -13 °C and the outside temperature is 30 °C, The initial temperature of the water is 22 °C, and the coefficient of performance is 31% of the ideal. Electrical energy costs $0.13 /kW-hr. The specific heat of ice is 0.5cal/g-°C.

What is the cost ($) of electricity to make 8 five pound bags of ice?

If the motor that drives the compressor consumes 950 W of electricity, how long does it take to make 8 bags of ice?
(include units with answer)

Answer 1

7303k T TH & QH COP = To = 260 Ideal - 303-260 10 Tc L COP I daad = 6.05 COP = 0.31 (6.05)=1.88 260k Remember: cop=! Od = |wl= f Qal TWI 1.88 4.88 In this case locl = mw Cew at & Mw Lf + Mv Cei cat 8 16 = 3.6349 T Qd = 3,63(4186) (220) + 3,63x 3.341047 (363)(2100) (0-(-13)) TQc) = 1.65x10CJ the net work is lwl = 100 = 8. 7810 1 Kwch = sxloº I (3600s) = 3.6x10^ the cost c = (5013) - (8.78x103) = 0.13 18.991109 3,6x106 c86.0317 @ Power P = 950w = 1W1h 8.78 x105 t=878x105 950 ? t=9245 kWh