A refrigeration cycle operating between two reservoirs receives energy QC from a cold reservoir at TC 5 275 K and rejects energy QH to a hot reservoir at TH 5 315 K. For each of the following cases, determine whether the cycle operates reversibly, operates irreversibly, or is impossible: (a) QC 5 1000 kJ, Wcycle 5 80 kJ. (b) QC 5 1200 kJ, QH 5 2000 kJ. (c) QH 5 1575 kJ, Wcycle 5 200 kJ. (d) 5 6.

Amass of m 1.5 kg of steam is contained in a closed rigid container. initially the pressure and temperature of the steam are: p 1.5 mpa and t 240°c (superheated state), respectively. then the temperature drops to t2= 100°c as the result of heat transfer to the surroundings. determine: a) quality of the steam at the end of the process, b) heat transfer with the surroundings. for: p1.5 mpa and t 240°c: enthalpy of superheated vapour is 2900 kj/kg, specific volume of superheated vapour is 0. 1483 m/kg, while for t 100°c: enthalpy of saturated liquid water is 419kj/kg, specific volume of saturated liquid water is 0.001043m/kg, enthalpy of saturated vapour is 2676 kj/kg, specific volume of saturated vapour is 1.672 m/kg and pressure is 0.1 mpa.

Different types of steels contain different elements that alter the characteristics of the steel. for each of the following elements, explain what the element does when alloyed with steel.

Thermal stresses are developed in a metal when its a) initial temperature is changed b) final temperature is changed c) density is changed d) thermal deformation is prevented e) expansion is prevented f) contraction is prevented