Engineering, 16.10.2020 14:01, karennayeli
Consider a two-stage cascade refrigeration system operating between the pressure limits of 1.2 MPa and 200 kPa with refrigerant-134a as the working fluid. The refrigerant leaves the condenser as a saturated liquid and is throttled to a flash chamber operating at 0.45 MPa. Part of the refrigerant evaporates during this flashing process, and this vapor is mixed with the refrigerant leaving the lowpressure compressor. The mixture is then compressed to the condenser pressure by the high-pressure compressor. The liquid in the flash chamber is throttled to the evaporator pressure and cools the refrigerated space as it vaporizes in the evaporator. The mass flow rate of the refrigerant through the low-pressure compressor is 0.15 kg/s. Assuming the refrigerant leaves the evaporator as a saturated vapor and the isentropic efficiency is 80 percent for both compressors.
Determine:
a. The mass flow rate of the refrigerant through the high-pressure compressor.
b. The rate of heat removal from the refrigerated space
c. The COP of this refrigerator.
d. The rate of heat removal and the COP if this refrigerator operated on a single-stage cycle between the same pressure limits with the same compressor efficiency and the same flow rate as in part (a) of the condenser and saturated vapor at the exit of each evaporator, and the compressor is isentropic.
Answers: 1
Engineering, 03.07.2019 14:10, volleyballfun24
If the thermal strain developed in polyimide film during deposition is given as 0.0044. assume room temperature is kept at 17.3 c, and thermal coefficient of expansion for the film and the substrate are 54 x 10^-6c^-1 and 3.3 x 10^-6c^-1respectively. calculate the deposition temperature.
Answers: 3
Engineering, 04.07.2019 18:10, DestyHilBan1183
Adouble-strand no. 60 roller chain is used to transmit power between a 13-tooth driving sprocket rotating at 300 rev/min and a 52-tooth driven sprocket. a) what is the allowable horsepower of this drive? b) estimate the center-to-center distance if the chain length is 82 pitches. c) estimate the torque and bending force on the driving shaft by the chain if the actual horsepower transmitted is 30 percent less than the corrected (allowable) power.
Answers: 3
Engineering, 04.07.2019 18:10, xboxdude06
Slip occurs via two partial dislocations because of (a) the shorter path of the partial dislocation lines; (b) the lower energy state through partial dislocations; (c) the charge balance.
Answers: 1
Consider a two-stage cascade refrigeration system operating between the pressure limits of 1.2 MPa a...
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