Engineering, 23.08.2019 01:30 mirandac9394

Arefrigeration plant operates in pretoria on refrigerant r134a at an evaporator pressure of 105kpa (gauge) and a condensing pressure of 920 kpa (gauge). there is a sub-cooling of 3k with a superheat of the gas entering the compressor of 8k. the compressor is a four-cylinder reciprocating compressor with a bore of 67mm and a stroke of 57mm with an estimated capacity of 35kw. the compressor is directly coupled to an electric motor running at 1470rev/min and a power consumption of 19,5 kw. calculate: 1. the clearance volume efficiency if the compressor clearance is 3,6% 2. the actual volumetric efficiency 3. the compression efficiency when the mechanical efficiency is 85% and the motor efficiency 90%.

Answers: 1

Show answers

Another question on Engineering

Engineering, 04.07.2019 18:10

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

Answer

Engineering, 04.07.2019 18:10

Apipe with an outside diameter of 15 cm is exposed to an ambient air and surrounding temperature of -20°c. the pipe has an outer surface temperature of 65°c and an emissivity of 0.85. if the rate of heat loss from the pipe surface is 0.95 kw per meter of length, the external convective heat transfer coefficient (h) is: (a) 12.5 w/m"k (b) 18.6 w/mk (c) 23.7 w/mk (d) 27.9 w/mk (e) 33.5 w/mk

Answers: 1

Answer

Engineering, 04.07.2019 18:20

An open feedwater heater operates at steady state with liquid entering at inlet 1 with t? = 40°c and pl = 1 .2 mpa. water vapor att2-200°c and p2 = 1.2 mpa enters at inlet 2. saturated liquid water exits with a pressure of pa 1.2 mpa. neglect heat transfer with the surroundings and all kinetic and potential energy effects, determine the mass flow rate of steam at inlet 2 if the mass flow rate of liquid water at inlet 1 is given as 2 kg/s.

Answers: 3

Answer

Engineering, 04.07.2019 19:10

What is a monomer? how do they form a ploymer from the view point of chemical bonding?

Answers: 1

Answer

You know the right answer?

Arefrigeration plant operates in pretoria on refrigerant r134a at an evaporator pressure of 105kpa (...

Questions