Title 5_Mastery Class Set 2.pdf ✅

REO - Mastery Class Set 2 1. A basic refrigeration cycle requires 25 kW where operating at a condenser temperature of 70 deg C and a COP of 3.50. What is the Sink temperature? a. -12.22 deg C b. -10.22 deg C c. -6.22 deg C d. -8.22 deg C 2. At a pressure of 1300 kPa, the mixture of steam and water has an entropy of 3 KJ/kg deg K. What is the Enthalpy of the mixture? At 1.3 MPa: sf = 2.2515, sg = 6. 4953, hf = 814.93, hfg = 1972. 7 a. 1,162.40 KJ/kg b. 1,234.45 KJ/kg c. 1,533.33 KJ/kg d. 1,627.71 KJ/kg 3. A liquid whose specific gravity is 1.75 flows in a 6cm horizontal PVC pipe. The total energy at a certain point in the flow is 80m. The elevation of the PVC pipe above a fixed datum is 2.6m. If the pressure at the specified point is 75kpa, determine the Velocity of flow and the power available at the point. a. 35.43m/s, 98262W b. 44.29m/s, 84372W c. 33.38m/s, 73933W d. 37.85m/s, 146,979W 4. Find the heat added during the process, when a quality mixture of 70% pressure of 500 Kpa is heated isothermally until its pressure is 300 Kpa. At 500 Kpa: sf = 1.8607, sfg = 4.9606 At 300 Kpa and 151.86 deg C: s = 7.0888 KJ/kg a. 535.16 KJ/kg b. 983.44 KJ/kg c. 765.34 KJ/kg d. 745.92 KJ/kg
5. A 4000 liters per hour of distillates are to be cooled from 21 deg. C to -12 deg. C and 12 percent of wax by weight is separated out at 15 deg. C. The specific heat of oil is 2 kJ/kg deg. C and S.G is 0.87. The specific heat of the wax is 2.5 and the latent heat of fusion is 290 kJ/kg. Allow 10 per cent for the losses, determine the capacity of the refrigerating machine. a. 372,987 BTU/Hr b. 372,960 BTU/Hr c. 109,285 BTU/Hr d. 901,328 BTU/Hr 6. An electronic barometer is used to measure an airplane’s altitude by comparing the barometric pressure at a given flying altitude to that on the ground. What will be the airplanes altitude if the Captain’s pilot measure the barometric pressure 700 mm-Hg, the ground says it is at 758 mm-Hg, and the average air density is 1.19 kg/cu m; 9.8 m/sec sq. a. 535 m b. 889 m c. 980 m d. 663 m 7. Water is pumped at 1 cum/s to an elevation of 5 meters through a flexible hose using 100 percent efficient pump rated at 100 kilowatts. Using the same length of hose, what size of motor is needed to pump 1 cum/s of water to a tank with no elevation gain? In both cases both end the hose are at temperature pressure. Neglect kinetic energy. a. 22 kW b. 36 kW c. 43 kW d. 51 kW 8. A newly acquired single acting air compressor with a clearance of 6 percent takes in air at atmospheric pressure and temperature of 85 deg. F, and discharges it at a pressure of 85 psia. The air handled is 0.25 cu ft per cycle measure at discharge pressure. If the compression is isentropic, determine the air compressor`s hp rating if the speed is at 750 rpm. a. 76 hp b. 86 hp c. 69 hp d. 96 hp
9. If the refrigeration system has a capacity of 2 tons, Which of the following statements is correct? a. The system has a COP of 2. b. The unit has 2 circuits c. The system has a refrigeration load of 400 Btu/min. d. The system uses 2 tons of refrigerants. 10. A closed feedwater heater, with a transmittance of U=350 Btu/hr- sq ft-F, uses condensing steam at a pressure of 20 psia (tsat=227.96 deg F) for heating 85,000 lb/hr of water from a temperature 60 deg F to a temperature of 215 deg F. Calculate the Transmitting Area? a. 234 sq ft b. 627 sq ft c. 622 sq ft d. 876 sq ft 11. A Cummins diesel power plant supplies energy for Batelco. During a 24-hour period, the plant consumed 240 gallons of at a temperature of 28 deg C and produces 3930 KW-hr. Industrial fuel used has a temperature of 23 deg API and was purchased at P30.00 per liter at a temperature of 15.6 deg C. What is the cost of fuel to produce one (1) KW-hr? a. P 41.07 /KW-hr b. P 10.10 /KW-hr c. P 6.87 /KW-hr d. P 15.00 /KW-hr 12. One of the newly installed Otto cycle operates on 0.1 lb/s of air from pressure of 13 psia and at temperature of 130 deg F at the beginning of compression. At the end of combustion, the temperature is 5000 deg R; compression ratio is at 5.5; hot air standard, k = 1.3. Compute for the horse power. a. 32.1 hp b. 52.0 hp c. 62.1 hp d. 42.0 hp 13. A vertical jet of water supports a load of 200N at a constant vertical height of 2m from the tip of the nozzle. The diameter of the jet is 25mm. Find the velocity of the jet at the nozzle tip. a. 28.32 m/s b. 23.28 m/s c. 21.13 m/s d. 22.82 m/s
14. A potable water ( P=62.4 lbm/cu ft) is flowing through a steel pipe. Pitot static gage registers 3.0 inches of mercury. What is the velocity of the water in the pipe? Note: PHg = 848.6 lbm/cu ft a. 61.7 ft/s b. 71.4 ft/s c. 84.1 ft/s d. 14.7 ft/s 15. Calculate the approximate load of the cooling tower if the entering and leaving temperatures are 96 deg F and 88 deg F, respectively and the flow rate of the water over the tower is 40 gpm. a. 6265.6 Btu/min b. 5662.6. Btu/min c. 2665.6 Btu/min d. 6526.6 Btu/min 16. A steam generator with economizer and air heater has an overall draft loss of 25.78 cm of water. If the stack gases are at a temperature of 177 deg C and if the atmosphere is at 101.3 kPa with a temperature of 26 deg C, what is the theoretical height of stack in meters is needed when no draft fan are used? Assume that the gas constant for the flue gases is the same as that of air. a. 651 m b. 671 m c. 631 m d. 611 m 17. What is the type of geothermal plant that is used when there is a presence of brine extracted from underground? a. Wet geothermal plant b. Binary geothermal plant c. Triple flash geothermal plant d. Double-flash geothermal plant 18. A brand new air standard engine has a compression ratio of 18 and a cut-off ratio of 4. Find the work in kJ per kg, if the intake air pressure and temperature are 100 kPa and 27 deg C. a. 1782 kJ/kg b. 2176 kJ/kg c. 2716 kJ/kg d. 1582 kJ/kg