The thermal efficiency of a reversible heat engine operating between two given thermal reservoirs is 0.4. The device is used either as a refrigerator or as a heat pump between the same reservoirs. Then the coefficient of performance as a refrigerator (COP)R and the co-efficient of performance as a heat pump (COP)HP are _______________?

Related Mcqs:

Colburn analogy is applicable for the value of Prandtl number from_________________?

A. 0.001 to 1 B. 0.6 to 120 C. 0.5 to 5 D. 120 to 400...

A 10 cm dia steam pipe, carrying steam at 180°C, is covered with an insulation (conductivity = 0.6 W/m.°C). It losses heat to the surroundings at 30°C. Assume a heat transfer co-efficient of 0.8 W/m2.°C for heat transfer from surface to the surroundings. Neglect wall resistance of the pipe and film resistance of steam. If the insulation thickness is 2 cms, the rate of heat loss from this insulated pipe will be__________________?

A. Greater than that for un-insulated steam pipe B. Less than that of the un-insulated steam pipe C. Equal to that of the un-insulated steam pipe D. Less than the steam pipe with 5 cms insulation...

What is Nusselt number ?

A. CP. μ/k B. hD/k C. h. CP/μ D. CP. μ/h...

Steam is to be condensed in a shell and tube heat exchanger, 5 m long with a shell diameter of 1 m. Cooling water is to be used for removing the heat. Heat transfer co-efficient for the cooling water, whether on shell side or tube side is the same. The best arrangement is_____________?

A. Vertical heat exchanger with steam on tube side B. Vertical heat exchanger with steam on shell side C. Horizontal heat exchanger with steam on tube side D. Horizontal heat exchanger with steam on shell side...

At what value of Prandtl number, the hydrodynamic and thermal boundary layers of a fluid flowing over a heated plate will be identical ?

A. 1 B. 1 D. None of these...