Engineering, 05.05.2020 07:36 whitethunder05
. A commercial refrigerator with refrigerant-134a as the working fluid is used to keep the refrigerated space at −30°C by rejecting its waste heat to cooling water that enters the condenser at 18°C at a rate of 0.25 kg/s and leaves at 26°C. The refrigerant enters the condenser at 1.2MPa and 65°C and leaves at 42°C. The inlet state of the compressor is 60 kPa and −34°C and the compressor is estimated to gain a net heat of 450 W from the surroundings. Determine (a) the quality of the refrigerant at the evaporator inlet, (b) the refrigeration load, (c) the COP of the refrigerator, and (d) the theoretical maximum refrigeration load for the same power input to the compressor.
Answers: 2
Engineering, 04.07.2019 18:10
Water at 55c flows across a flat plate whose surface temperature is held constant at 95c. if the temperature gradient at the plate's surface for a given value of x is 18 c/mm, find a) local heat transfer coefficient. b) heat flux
Answers: 3
Engineering, 04.07.2019 18:10
Burgers vector is generally parallel to the dislocation line. a)-true b)-false
Answers: 2
Engineering, 04.07.2019 18:20
Asolid cylinder is concentric with a straight pipe. the cylinder is 0.5 m long and has an outside diameter of 8 cm. the pipe has an inside diameter of 8.5 cm. the annulus between the cylinder ad the pipe contains stationary oil. the oil has a specific gravity of 0.92 and a kinematic viscosity of 5.57 x 10-4 m2/s. most nearly, what is the force needed to move the cylinder along the pipe at a constant velocity of 1 m/s?
Answers: 3
Engineering, 04.07.2019 18:20
Refrigerant-134a enters the compressor of a refrigerator as superheated vapor at 0.14 mpa and -10°c at a rate of 0.05 ka/s and leaves at 0.8 mpa and 50°c. the refrigerant is cooied in the condenser to 0.72 mpa and 26'c. it is then throttled to 0.15 mpa. sketch the t-s diagram for the system and evaluate: 6) the rate of heat removai from the refrigerated space (kw), it) the power input to the compressor (kw), ii) the isentropic efficiency of the compressor (%), and iv) the cop of the refrigerator.
Answers: 2
. A commercial refrigerator with refrigerant-134a as the working fluid is used to keep the refrigera...
Chemistry, 14.04.2020 17:32
History, 14.04.2020 17:32
Biology, 14.04.2020 17:32
English, 14.04.2020 17:32
Mathematics, 14.04.2020 17:32
Law, 14.04.2020 17:32
Mathematics, 14.04.2020 17:32
Biology, 14.04.2020 17:32
Mathematics, 14.04.2020 17:32
Computers and Technology, 14.04.2020 17:32