Using an engine of 30% thermal efficiency to drive a refrigerator having a COP of 5, what is the heat input into the engine for each MJ removed from the cold body by the refrigerator? If this system is used as heat pump, how many MJ of heat would be available for heating for each MJ of heat input to the engine.

An engine works on the basis of Carnot cycle operating between temperatures of 800 K and 400 K. If the heat supplied is 100 kW, the output is

Q4/ A particular power plant operates with a heat source reservoir at 350 °C and a heat sink reservoir at 30 °C. It has a thermal efficiency equal to 55% of the Carnot engine therma' efficiency for the same temperatures. 1. What is the thermal efficiency of the plant? 2. To what temperature must the heat source reservoir be raised to increase the thermal efficiency of the plant to 35%?

A heat engine has a thermal efficiency of 70%. During each cycle the engine does 400J of work. What is the magnitude of waste heat rejected to the low temp reservoir?

mechanical cycle, A reversed Carnot cycle is given which operates between the temperature limits of 27°C and -3°C, So what will be the ratio of the COP of a refrigerator to that of a heat pump?

4- An engineer has designed an efficient and economic engine to receive 500kJ of heat per cycle from a boiler at 652C and rejects heat to a river at 39C to maintain the environmental and health regulation. (a) What's the highest thermal efficiency level for this engine? (b) the amount of heat rejected to the river per cycle for case (a) to meet the public health, safety and environmental regulation.

B) A reversible heat engine operates between two reservoirs at temperatures of 600°C and 40°C. The engine drives a reversible refrigerator which operates between reservoirs at temperatures of 40°C and -20°C. The heat transfer to the heat engine is 2000 kJ and the net work output for the combined engine refrigerator is 360 kJ. (i) Calculate the heat transfer to the refrigerant and the net heat transfer to the reservoir at 40°C. (ii) Reconsider (i) given that the efficiency of the heat engine and the C.O.P. of the refrigerator are each 40 per cent of their maximum possible values.

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A heat engine is assumed to operate on a Carnot cycle. It receives 900kJheat from a high temperature reservoir at 550oC and rejects heat to a lowtemperature reservoir at 30oC.a. Calculate the thermal efficiency of the cycle.b. What is QH and QL?c. What is the net work produced by this cycle?d. Does this process violate Kelvin-Plank statement? Explain.e. An inventor claimed that he built a heat engine operating between the same reservoirs that give a thermal efficiency of 80%.Comments about his claim.f. Draw this process on a Ts diagram with proper labelling.g. If the cycle is reversed and operated as a heat pump, calculate itsperformance.