Find the required work to transfer 1200 J of heat from the sink (cold body) at -90° Cto source (hot body) at 35°C in the case of refrigerator (а) 820 J (b) 530 J (c) 640 J (d) 580 J

It is claimed that a certain cyclical heat engine operates between the temperatures of TH = 460°C and TC = 153°C and performs W = 4.1MJ of work on a heat input of QH = 5.05 MJ. - How much heat, in megajoules, would be discharged into the low-temperature reservoir?

(a) What is the best coefficient of performance for a heat pump that has a hot reservoir temperature of 59.3°C and a cold reservoir temperature of -12.7°C? (b) How much heat in kilocalories would it pump into the warm environment if 3.60 x 10' ) of work (10.0 kw · h) is put into it? kcal (c) Assume the cost of this work input is 10c/kW · h. Also assume that the cost of direct production of heat by burning natural gas is 85.0c per therm (a common unit of energy for natural gas), wher a therm equals 1.055 x 108 J. Compare the cost of producing the same amount of heat by each method. cost of heat pump cost of natural gas Additional Materials OReading

(a) When the steam engine is running between 120°C and 30°C, how many Js of calories are there in the heat source to get 1000 Js of work? (b) When an ideal gas with Cp=5 cal/(mol·K) is compressed to 25°C, and 10°C through an adiabatic and reversible process, what is the final temperature of the gas? (c) In an ideal gas turbine power device, the pressure ratio is 6, the temperature entering the compressor is 27°C, and the maximum allowable temperature of the turbine is 816°C. What is the efficiency of this power device when it is carried out in reversible operation? However, the specific ratio is 1.4.

One of the most efficient engines ever built is a coal-fired steam turbine engine in the Ohio River valley, driving an electric generator as it operates between 1,870°C and 430°C. (a) What is its maximum theoretical efficiency? (b)Its actual efficiency is 42.0%. How much mechanical power does the engine deliver if it absorbs 1.35 ✕ 105 J of energy each second from the hot reservoir?

Calculate the net work output of a heat engine following path ABCDA in the figure below, where  V1 = 2.6 ✕ 10−3 m3  and  V2 = 10.4 ✕ 10−3 m3.

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