Problem 3 A vapor compression heat pump cycle requires that the evaporator and condenser operate within 10°C of their respective heat reservoirs. The cycle employs R134a as the working fluid, which exits the evaporator as a saturated vapor and exits the condenser as a saturated liquid. The compressor operates with an isentropic efficiency of 82%. If the desired inside temperature is 21 °C and the outside temperature is 0 °C, determine: The appropriate cycle pressures, The compressor power in kW, Compare the actual coefficient of performance to the coefficient of performance for a Carnot heat pump cycle operating between the inside and outside temperatures given above.

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.

Ajournal bearing has a journal diameter of 3.250 in with a unilateral tolerance of 20.003 in. the bushing bore has a diameter of 3.256 in and a unilateral tolerance of 0.004 in. the bushing is 2.8 in long and supports a 700-lbf load. the journal speed is 900 rev/min. find the minimum oil film thickness and the maximum film pressure for both sae 20 and sae 20w-30 lubricants, for the tightest assembly if the operating film temperature is 160°f. a computer code is appropriate for solving this problem.

Draw the engineering stress-strain curve for (a) bcc; (b) fcc metals and mark important points.