12:30Mechanical Engineering Thermodynamics - Lec 6, pt 4 of 4: Refrigerators and Heat PumpsRon Hugo111
Textbook QuestionA man stands on the roof of a 15.0-m-tall building and throws a rock with a speed of 30.0 m/s at an angle of 33.0° above the horizontal. Ignore air resistance. Calculate (d) Draw x-t, y-t, υx–t, and υy–t graphs for the motion.451Has a video solution.
Multiple ChoiceA refrigerator has a coefficient of performance of 2.4. Each cycle, it takes in 3×104 J of heat from the cold reservoir. How much is expelled to the hot reservoir?232Has a video solution.
Multiple ChoiceFreezing a kilogram of water, initially at 20°C, requires your refrigerator to remove about 417kJ of thermal energy from the water. If the coefficient of performance of your refrigerator is 5.0, how much heat is exhausted into your kitchen when you freeze a kilogram of water?174
Multiple ChoiceWhat is the maximum possible coefficient of performance for a refrigerator operating between 2.0°C (a typical refrigerator temperature) and 20°C (a typical kitchen temperature)?149
Textbook QuestionA certain brand of freezer is advertised to use 730 kW•h of energy per year. (c) What is the theoretical maximum amount of ice this freezer could make in an hour, starting with water at 20.0°C?443Has a video solution.
Textbook QuestionA certain brand of freezer is advertised to use 730 kW•h of energy per year. (a) Assuming the freezer operates for 5 hours each day, how much power does it require while operating?148Has a video solution.
Textbook QuestionA refrigerator has a coefficient of performance of 2.25, runs on an input of 135 W of electrical power, and keeps its inside compartment at 5°C. If you put a dozen 1.0-L plastic bottles of water at 31°C into this refrigerator, how long will it take for them to be cooled down to 5°C? (Ignore any heat that leaves the plastic.)757Has a video solution.
Textbook QuestionThe coefficient of performance K = H/P is a dimensionless quantity. Its value is independent of the units used for H and P, as long as the same units, such as watts, are used for both quantities. However, it is common practice to express H in Btu/h and P in watts. When these mixed units are used, the ratio H/P is called the energy efficiency ratio (EER). If a room air conditioner has K = 3.0, what is its EER?252Has a video solution.