Engineering, 20.08.2020 20:01 jina18

A refrigeration 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

Aflywheel accelerates for 5 seconds at 2 rad/s2 from a speed of 20 rpm. determine the total number of revolutions of the flywheel during the period of its acceleration. a.5.65 b.8.43 c. 723 d.6.86

Answers: 2

Answer

Engineering, 04.07.2019 18:10

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

Answers: 1

Answer

Engineering, 04.07.2019 18:10

Items are similar to the free issue items, but their access is limited. (clo5) a)-bin stock items free issue b)-bin stock controlled issue c)-critical or insurance spares d)-rebuildable spares e)-consumables

Answers: 1

Answer

Engineering, 04.07.2019 18:10

An air compression refrigeration system is to have an air pressure of 100 psia in the brine tank and an allowable air temperature increase of 60°f for standard vapor compression cycle temperatures of 77 f entering the expansion cylinder and 14 f entering the compression cylinder, calculate the coefficient of performance a. 2.5 b 3.3 c. 4.0 d. 5.0

Answers: 3

Answer

You know the right answer?

A refrigeration plant operates in Pretoria on refrigerant R134a at an evaporator pressure of 105kPa...

Questions