Chapter 8, Problem 8.10P

Heat engine and refrigerator. Consider a heat engine operating between temperatures Th and Tj. During each cycle with time At, work W is extracted, so Pout = W/At. (a) Assuming the processes are all reversible, what is the efficiency of this heat engine, n = Wout/Qn? (b) Now assume that the low temperature of the heat engine is lowered by a reversible refrigerator, such that the heat engine operates between Th and T. The refrigerator takes input power Pin = Win/At and operates between T and T, where Ti < T. Draw an energy- entropy flow diagram. (c) Calculate the net efficiency (Wout - Win)/Qh. Is the efficiency of this system higher, lower, or the same as your answer for (a)?

THERMODYNAMICS (UPVOTE WILL BE GIVEN. PLEASE WRITE THE COMPLETE SOLUTIONS. NO LONG EXPLANATION NEEDED. ANSWER IN 3 DECIMAL PLACES. BOX THE FINAL ANSWERS. PLEASE ANSWER ALL Two Carnot heat engines operate in series. The first heat engine absorbs heat of 100kW at 400°C while second heat engine rejects heat at 100°C. If the efficiencies of the heat engines are the same,a. Draw the schematic diagram of the systemb. Find the intermediate temperature in between the heat enginesc. Heat rejected for both heat engines

Q2: Source 1 can supply energy at the rate of 12000 kJ/min at 320°C. A second source 2 can supply energy at the rate of 120000 kJ/min at 70°C. Which source (1 or 2) would you choose to supply energy to an ideal reversible heat engine that is to produce large amount of power if the temperature of the surroundings is 35°C?

b) Refrigerators are systems that are used to remove heat from a cooled space then reject heat to a space of higher temperature. Consider a refrigerator operating at normal conditions, removing heat from a cool space at a rate of 150 kJ/min to ensure the refrigerated space is kept at -5 °C. If the surrounding air is at 27 °C and assuming that the refrigerator is operating as a Carnot cycle, determine: 1) The rate of heat being rejected to the surrounding in kJ/min The coefficient of performance of this refrigeration process 11) 111) The minimum required power on this process (give your answer in kW)

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An air conditioner is a device used to cool the inside of a home. It is, in essence, a refrigerator in which mechanical work is done and heat removed from the (cooler) inside and rejected to the (warmer) outside. A home air conditioner operating on a reversible Carnot cycle between the inside, absolute temperature T2, and the outside, absolute tempera- ture T1 > T2, consumes P joules/sec from the power lines when operating continuously. (a) In one second, the air conditioner absorbs Q2 joules from the house and rejects Q1 joules outdoors. Develop a formula for the efficiency ratio Q2/P in terms of T1 and T2. (b) Heat leakage into the house follows Newton's law Q = A(T, – T2). Develop a formula for T, in terms of T1, P, and A for continuous operation of the air conditioner under constant outside temperature T and uniform (in space) inside temperature T2. (c) The air conditioner is controlled by the usual on-off thermostat and it is observed that when the thermostat set at 20°C and an…

What is the highest COP that a refrigerator operating between temperature levels TL and TH can have?

A heat engine with a thermal efficency of 45% rejects 500kJ/kg of heat. How much heat does it recieve?

A heat pump operates with a Coefficient of Performance equal to 8. What is the COP if this cycle were to operate as a refrigerator?