Calculate the specific volume of an air-vapor mixture in cubic meters per kilogram of dry air when the ff. conditions: t=30°C, w=0.015 kg/kg, and Pt =90kpa

A. 0.99 m3/kg C. 0.79 m3/kgB. 0.89 m3/kg D. 0.69 m3/kg

A

A coil has an inlet temperature of 60 °F and an outlet of 90°F. If the mean temperature of the coil is 110°F. Find the bypass factor of the coil.

A. 0.20 C. 0.40 B. 0.30 D. 0 .50

C

A rectangular duct has a diameter of 0.25 m by 1 m. determines of the equivalent diameter of the duct.

A. 0.40 m C. 0.70 mB. 0.80 m D. 0.30 m

A

The mass of an outside air at 50°C in an air conditioning unit is 60 kg. Find the temperature after mixing if the outside air mixed with 40 kg with recirculated air at 35°C.

A. 44°C C. 52°CB. 39°C D. 47°C

A

A creamery must cool 20,000 liters of milk received each day from initial temperature at 29°C to a final temperature at 2°C in 5 hours. If refrigeration losses amount to 10 percent of the cuilling load, what must be the capacity of the refrigeration machine? Note: specific heat of milk 3.9 kJ/kg-K and S.G. = 1.05

A. 38.5 TOR C. 37.5 TORB. 36.5 TOR D. 39.5 TOR

A

How many tons of refrigeration are required to produce 10 metric tons of ice per day at -10°C from raw water at 22°C if miscellaneous losses are 15% of the chilling and freezing load?

A. 17 TOR C. 15 TORB. 20 T0R D. 24 TOR

A

Five hundred kilogram of poultry enters a chiller at 8°C and are frozen and chilled to a final temperature of -18°C for a storage in 15 hours. The specific heat above and below the freezing are 3.18 kJ/kg-K°C and 1.55 kJ/kg-K°C respectively. The latent heat is 246 kJ/kg and the freezing temperature is -5°C. Compute the product load.

A. 2.75 kW C. 2.95 kWB. 2.85 kW D. 3.15 kW

B

Fish weighing 11,000 kg with a temperature of 20°C is brought to a cold storage and which shall be cooled to -10°C in 11 hours. Find the required plant refrigerating capacity in tons of refrigeration if the specific heat of fish is 0.7 kCal/kg°C above freezing and 0.30 kCal/kg°C below freezing point which is -3°C. The latent heat of freezing is 55.5 kCal/kg.

A. 25.26 C. 14.38B. 15.26 D. 24.38

D

The power requirement of Carnot refrigeration in maintaining a low temperature region at 300 K 1.5 kW per ton. Find the heat rejected.

A. 4.02 kW C. 5.02 kWB. 7.02 kW D. 6.02 kW

C

A vapor compression refrigeration system is designed to have a capacity of 150 tons of refrigeration. It produces chilled water from 22°C to 2°C. Its actual coefficient of performance is 5.86 and 35% of the power supplied to the compressor is lost in the form of friction and cylinder cooling losses. Determine the condenser cooling water required for a temperature rise of 10°C.

A. 14.75kg/s C. 18.65 kg/sB. 15.65 kg/s D. 13.75 kg/s

ADetermine the heat extracted from 2000 kg of water from 25°C to ice at -10°C.

A. 621,150 kJ C. 821,150 kJ B. 721,159 kJ D. 921,150 kJ

D

A single acting, twin cylinder, Ammonia compressor with bore equal to stroke is driven by an engine at 250 rpm. The machine is installed in a chilling plant to produce 700 kW of refrigeration at -18°C evaporating temperature. At this temperature the cooling effect per kg mass is 1160 kJ. The specific volume of vapor entering the compressor is 0.592 m3 per kilogram. Assume 85% volumetric efficiency. Determine the bore in mm.

A. 400 mm C. 450 mmB. 300 mm D. 500 mm

A

A cylindrical flash tank mounted with its axis horizontal is used to separate liquid ammonia from ammonia vapor. The ammonia vapor bubbles through the liquid with 70 m3/min leaving the disengaging surface. The disengaging rate is limited to 60 m/min and the liquid level is to operate with the liquid level one-third of the diameter from the top. Determine the diameter if the tank is 1.5 m long.

A. 830 mm C. 860 mmB. 730 mm D. 760 mm

A

A 150 Hp motor is used to drive a compressor. If the heat loss from the compressor is 25 kW and the mass flow rate of the refrigerant entering the compressor is 0.50 kg/s, determine the difference of the enthalpies between the inlet and outlet of the compressor.

A. 143.80 kJ/kg C. 173.80 kJ/kgB. 153.80 kJ/kg D. 183.80 kJ/kg

C

Determine the estimated condenser load for an open-type compressor having a cooling capacity of 16,500 Btu/hr and a heat rejection factor of 1.32.

A. 22,280 Btu/hr C. 21,780 Btu/hrB. 20,780 Btu/hr D. 91,780 Btu/hr

CTo cool farm products 300 kg of ice at -4.4°C are placed in bunker twenty four hours later the ice have melted into water at 7.2°C. What is the average rate of cooling provided by the ice in kJ/Hr?

A. 2679.28 kJ/Hr C. 3679.28 kJ/HrB. 5679.28 kJ/Hr D. 4679.28 kJ/Hr

D

The load on a water–cooled condenser is 90,000 Btu/hr. if the quantity of water circulated through the condenser is 15 gpm, determine the temperature rise of the water in the condenser.

A. 12°F C. 16°FB. 14°F D. 18°F

A

If the load on a water–cooled condenser in 150,000 Btu/hr and the temperature rise of the water in the condenser is 10°F. What is the quantity of water circulated in gpm?

A. 30 C. 20B. 40 D 50

A

The weight of ammonia circulated in a machine is found to be 21.8 lb/hr. if the vapor enters the compressor with a specific volume of 9.6 Ft3/hr, calculate the piston displacement, assuming 80% percent volume efficiency.

A. 261.6 Ft3/hr C. 281.8 Ft3/hrB. 271.6 Ft3/hr D. 291.6 Ft3/hr

A

A single stage ammonia compressor is producing 10 tons of refrigeration and the power consumed is 15 Hp. Suction pressure is 25 psi, condensing pressure is 180 psi. Brine temperature is 20°F off brine cooler. Determine the actual coefficient of performance.

A. 10.14 C. 12.14B. 11.14 D. 13.14

D

In an ammonia condensing machine (compressor plus condenser) the water used for condensing is 55°F. Calculate the ideal COP.

A. 11.875 C. 10.875B. 12.875 D. 13.875

A

How much refrigeration capacity is required to cool 2000 cfm of air from 85°F to 70°F?

A. 2.7 TOR C. 1.7 TORB. 3.7 TOR D. 4.7 TOR

A

Determine the coil face area required to maintain a face velocity of 400 Ft/min if the air flow rate over the coil is 2100 Ft3/hr

A. 3.25 Ft2 C. 5.25 Ft2

B. 4.45 Ft2 D. 6.25 Ft2

C

A centrifugal pump discharge 20 L/s against a head of 17 m when the speed is 1500 rpm. The diameter of the impeller was 30 cm and the brake horsepower was 6.0. A geometrically similar pump 40 cm in diameter is to run at 1750 rpm. Assuming equal efficiencies, what brake horsepower is required?

A. 51.55 HP C. 40.15 HPB. 50.15 HP D. 45.15 HP

C

A pump delivers 20 cfm of water having a density of 62 lb/ft3. The suction and discharge gage reads 5 in. Hg vacuum and 30 psi respectively. The discharge gage is 5 ft above the suction gage. If pump efficiency is 70%, what is the motor power?

A. 5.31 Hp C. 4.31 HpB. 3.31 Hp D. 6.31 Hp

C

Calculate the air power of a fan that delivers 1200 °F Ft3/hr of air through a 1m by 1.5m outlet. Static pressure is 120 mm WG and the density of air is 1.18

A. 20.45 kW C. 30.45 kWB. 25.64 kW D. 35.64 kW

B

The piston displacement of a double acting compressor is 0. 358 m3 delivers gas from 101.325 kPa and 300 K to 675 kPa at the rate of 0.166 m3/s at 150 rpm. Value of n for compression and expansion is 1.33. Find the compressor percent clearance.

A. 19.66 C. 15.69B. 10.75 D. 16.96

D

Determine the specific speed of a centrifugal pump delivers 7500 gpm acting against a total head of 370 ft and operating at 1000 rpm.

A. 1072 rpm C. 1041 rpmB. 1027 rpm D. 1014 rpm

B

An induced draft fan is used to extract 270000 m3 of flue gas per hour from a boiler furnace. The fan is to deliver at a total pressure of 250 mm water gage. Determine the size of the electric motor in kW if a mechanical efficiency of 55% is considered.

A. 444.33 kW C. 433.44 kWB. 343.44 kW D. 334.44 kW

D

The fan has a total head of 190 m and static pressure of 20 cm WG. If the air density is 1.2 kg/m3. What is the velocity of air flowing?

A. 16.21 m/s C. 16.66 m/sB. 27.21 m/s D. 17.77 m/s

D

A pump delivers 500 gpm of water against a total head of 200 ft and operating at 1770 rpm. Changes have increased the total head to 375 ft. At what rpm should the pump be operated to achieve the new head at the same efficiency?

A. 2800 rpm C. 3434 rpmB. 3600 rpm D. 2424 rpm

D

The diesel electric plant supplies energy for meralco. During a 24 hr period, the plant consumed 200 gallons of fuel at 28°C and produced 3930 Kw-hr. industrial fuel is used is 28°API and was purchased at P 5.50 per liter at 15,6°C. What should the cost of fuel be produced one kw-hr?

A. P 1.05 C. P 1.069B. P 1.10 D. P 1.00

A

A boiler contains 3.5 tons of water initially having 40 ppm dissolved solids after 24 hrs the dissolved solids in the water is 2500 ppm. If the feed rate is 875 kg/hr, find the ppm of dissolved solids contained in the feed water.

A. 410 ppm C. 390 ppmB. 320 ppm D. 420 ppm

A

A travelling-grate stoker can burn bituminous coal with 10% moisture and 10% ash at a rate of 500,000 Btu/hr-Ft2. A boiler with a steam rating of 200,000 lb/hr will be fired with the above fuel having a high heat value of 12,200 Btu/lb. if the boiler efficiency is 80%, and if it takes 1000 BTU to evaporate and superheat one pound of feed water to the desired temperature, find the hourly coal supply and grate area needed.

A. 20,500 lb, 500 Ft2 C. 28,200 lb, 400 Ft2

B. 26,400 lb, 700 Ft2 D. 22,600 lb, 200 Ft2

A

A steam is expanded through a nozzle and the enthalpy drop per kg of steam from the initial pressure to the final pressure is 60 kJ. Neglecting the friction, find the velocity of discharge and the exit area of the nozzle to pass 0.20 kg/s if the specific volume of the steam at exit is 1.5 m3/kg.

A. 346.4 m/s, 879 m2 C. 765.6 m/s, 467 m2

B. 356.7 m/s, 278 m2 D.346.4 m/s, 866 m2

D

A 60 MW steam turbine generator power plant has a full-load steam rate of 8 kg/kW-hr. assuming that no-load steam consumption as 15% of full-load steam consumption, compute for the hourly steam consumption at 75% load, in kg/hr.

A. 37,800 kg/hr C. 30,780 kg/hrB. 38,700 kg/hr D. 30,870 kg/hr

A

The feed water to a boiler is 92% condensate and 8% make-up containing 270 ppm solids. What weights of solids enter the boiler per hour at 22,680 kg per steam evaporation?

A. 0.49 kg solids/hr C. 0.39 kg solids/hrB. 0.59 kg solids/hr D. 0.69 kg solids/hr

A

The 1370 diameter steam drum on a boiler is 2440 mm long has a 250 mm gage glass at mid-drum level. Find the maximum steam generation that could be cared for by a blow down of half a water gauge each 8 hr. shift. Pressure, 17.5 kg/cm2 gage. Sr = 150 PPM, Sb = 2000 PPM

A. 450.59 kg/hr C. 650.59 kg/hrB. 550.59 kg/hr D. 750.59 kg/hr

B

Given a horizontal conveyor, 46 m centers, 175 pounds per hr capacity of handling bituminous coal at 0.5 m/s with 800 kg per m3. Other data as follows

Flight width and depth 610 mm x 200 mmQuantity of material 0.108 mm3/mCoefficient of friction elements 0.10Material coefficient of friction 0.59

Assume an engineering-type chain with sleeve bearing rollers weighing with flights, 89.3 kg/m. Calculate the chain pull in kg

A. 2180.33 C. 1555.36B. 4550.10 D. 3166.46

D

Air is drawn into a gas turbine working on the constant pressure cycle at 1 bar 21°C and compressed to 5.7 bars. The temperature at the end of heat supply is 680°C. Taking expansion and compression to be adiabatic where Cv = 0.718 kJ/kg-K, Cp = 1.055 kJ/kg-K, calculate the heat energy supplied per kg at constant pressure.

A. 472 kJ/kg C. 501 kJ/kgB. 389 kJ/kg D. 489 kJ/kg

A

In an air-standard Bryton cycle, the compressor receives air at 101.325 kPa, 21°C and it leaves at the rate of 4 kg/s. determine the turbine work if the temperature of the air entering the turbine is 1000°C

A. 3000 kW C. 2028 kWB. 2701 kW D. 3500 kW

C

The net power output of an air-standard Brayton cycle is 200 kW. Air enters the compressor at 32°C and leaves the high-temperature heat exchanger at 800°C. What is the mass flow rate of air if it leaves the turbine at 350°C?

A. 0.57 kg/s C. 0.77 kg/sB. 0.67 kg/s D. 0.87 kg/s

D

In an air-standard Brayton cycle the inlet temperature and the pressure are 20°C and 101.325 kPa. The turbine inlet conditions are 1200 kPa and 900°C. Determine the air flow rate if turbines produce 12 MW.

A. 21.41 kg/s C. 19.25 kg/sB. 20.20 kg/s D. 18.10 kg/s

B

A gas turbine power plant operating on the Brayton cycle delivers 15 MW to a standby electric generator. What are the mass flow rate and the volume flow rate of air if the minimum and maximum pressures are 100 kPa and 500 kPa respectively, and temperature of 20°C and 1000°C?

A. 31.97 kg/s, 26.88 m3/s C. 41.97 kg/s, 26.88 m3/sB. 36.98 kg/s, 28.99 m3/s D. 46.98 kg/s, 28.99 m3/s

A

A hydro-electric power plant consumes 60,000,000 kW-hr per year. What is the net if the expected flow is 1500 m 3/min and over-all efficiency is 63%?

A. 34.34 m C. 44.33 mB. 43.43 m D. 33.44 m

C

A pelton type turbine has a gross head of 40 m and a friction head loss of 6 m. What is the penstock diameter if the penstock length is 90 m and the coefficient of friction head loss is 0.0001 (Morse).

A. 2040 mm C. 2440 mmB. 3120 mm D. 2320 mm

A

A hydro-electric impulse turbine is directly coupled to a 24 pole, 60 Hz alternator. It has a specific speed of 60 rpm and develops 3000 Hp. What is the required diameter assuming a peripheral speed ratio of 0.45?

A. 0.661 m C. 0.443 mB. 0.552 m D. 0.775 m

A

The tail water and the headwater of a hydro-electric power plant are 150 m and 200 m respectively. What is the water power if the flow is 15 m3/s and a head loss of 10% of the gross head?

A. 6,621.75 kW C. 5,621.76 kWB. 7,621.65 kW D. 4,621.56 kW

A

In a hydro-electric plant, water flows at 10 m/s in a penstock of 1 m2 cross-sectional area. If the net head of the plant is 30 m and the turbine efficiency is 85%, what is the turbine output?

A. 2,501.55 kW C. 3,626.34 kWB. 2,100.21 kW D. 3,124.65 kW

A

A 75 MW power plant has an average load of 35,000 kW and a load factor of 65%. Find the reserve over peak.

A. 21.15 MW C. 25.38 MWB. 23.41 MW D. 18.75 MW

A

A power plant is said to have/had a use factor of 48.5% and a capacity factor of 42.4%. How many hrs. Did it operate during the year?

A. 6,600.32 hrs C. 8,600.32 hrsB. 7,658.23 hrs D. 5,658.23 hrs

B

A 50,000 kW steam plant delivers an annual output of 238,000,000 kW-hr with a peak load of 42,860 kW. What is the annual load factor and capacity factor?

A. 0.634, 0.534 C. 0.634, 0.543B. 0.643, 0.534 D. 0.643, 0.534

C

Calculate the use factor of a power plant if the capacity factor is 35% and it operates 8000 hrs during the year?

A. 38.325 % C. 35.823 %B. 33.825 % D. 32.538 %

A

A 39.5 m high chimney of radial brick masonry is described by the ff. top and bottom. D2 = 1.9 m, d2 = 1.5 m, D1 = 3.2 m, d1 = 2.3 m. Determine the moment due to wind load.

A. 172,051 kg-m C. 150,160 kg-mB. 160,388 kg-m D. 182,030 kg-m

D

It is desired to deliver 5 gpm at a head of 640 ft in a single stage pump having s specific speed not to exceed 40. If the speed is not to exceed 1352 rpm, how many stages are required?

A. 3 C. 5B. 4 D. 2

D

A centrifugal pump discharge 20 L/s against a head of 17 m when the speed is 1500 rpm. The diameter of the impeller was 30 c, and the brake horsepower was 6.0. A geometrically similar pump 40 cm in diameter is to run at 1750 rpm. Assuming equal efficiency, what brake horsepower is required?

A. 51.55 Hp C. 40.15 HpB. 50.15 Hp D. 45.15 Hp

C

A condensate pump at sea level takes water from a surface condenser where the vacuum is 15 in. of mercury. The friction and turbulence in the piping in the condenser hot well and the pump suction flange is assumed to be 6.5 ft. if the condensate pump to be installed has a required head of 9 ft, what would be the minimum height of water level in the hot well that must be maintained above the centerline of the pump to avoid cavitations?

A. 2.5 ft C. 18 ftB. 15.5 ft D. 5.5 ft

BA pump delivers 2o cfm of water having a density of 62 lb/ft 3. The suction discharge gage reads 5 in. Hg vacuum and 30 psi respectively. The discharge gage is 5 ft above the suction gage. If the pump efficiency is 70%, what is motor power?

A. 5.31 Hp C. 4.31 HpB. 3.31 Hp D. 6.31 Hp

C

A fan has a total head of 190 m and a static pressure of 20 cm WG. If the air density is 1.2 kg/m3, what is the velocity of air flowing?

A. 16.21 m/s C. 16.66 m/sB. 17.21 m/s D. 17.766 m/s

D

A jet of water is discharge through a 1 – inch diameter orifice under constant head of 2.1 ft total discharge is 228 lb, in 90 seconds. The jet is observed to pass through a point 2 ft downward and 4 ft away from vena contrata. Coefficient of velocity.

A. O.786 C. 0.567B. 0.685 D. 0.345

B

A jet of water is discharge through a 1 – inch diameter orifice under constant head of 2.1 ft total discharge is 228 lb, in 90 seconds. The jet is observed to pass through a point 2 ft downward and 4 ft away from vena contrata. Coefficient of velocity.

A. 0.976 C. 0.567B. 0.758 D. 0.845

A

What is the velocity of sound 150°F (66°C) air at a standard pressure? Note: density of air @ 150°F is 0.064 lbm/ft3.

A. 1215 ft/s C. 2345 ft/sB. 3245 ft/s D. 4321 ft/s

A

Ideal Oxygen is throttled at 140°F from 10 atm to 5 atm. What is the temperature change?

A. 0 C. infinityB. Negative D. 1

A

A duct 0.40 m high and 0.80 wide suspended from the ceiling in a corridor, makes a right angle turn in the horizontal plane. The inner radius is 0.2 m and the outer radius is 1.0 m measured from the same center. The velocity of air in the duct is 10 m/s. compute the pressure drop in this elbow. Assuming; f = 0.3, ρ = 1.204 kg/m3

and L = 10 m.A. 341 Pa C. 143 PaB. 441 Pa D. 144 Pa

A

To what weight will 68°F ethyl alcohol rise in a 0.005 inch internal diameter glass capillary tube? The density of alcohol is 49 lbm/ft3. Where: β = 0° = angle of contact angle and surface tension σ = 0.00156 lbm/ft @ 68°F.

A. 0.3056 ft C. 0.4312 ftB. 0.2504 ft D. 0.2432 ft

A

What is the velocity of sound in 150°F (66°C) air at a standard pressure? Note: density of air @ 150°F is 0.064 lbm/ft3.

A. 1295 ft/s C. 2345 ft/sB. 3245 ft/s D. 1096 ft/s

A

What is the pressure 8000 ft below the water surface of the ocean? Neglect compressibility.

A. 512,000 psf C. 157,000 psfB. 324,500 psf D. 213,000 psf

A

If atmospheric air 14.7 psia and 60°F at sea level, what is the pressure at 12000 ft altitude if air is incompressible? Note: @ 60°F; the density of air is 0.0763 lbm/ft3 ; P1 = 14.7 psia

A. 5.467 psia C. 8.342 psiaB. 9.345 psia D. 2.346 psia

C

If atmospheric air 14.7 psia and 60°F at sea level, what is the pressure at 12000 ft altitude if air is compressible? Note @ 60°F; the density of air is 0.0763 lbm/ft3 ; P1 = 14.7 psia

A. 5.467 psia C. 8.342 psiaB. 9.53 psia D. 2.346 psia

B

A two-pass surface condenser is to be designed using overall heat transfer coefficient of 480 BTU/°F lbm/ft2 of outside tube surface. The tubes are to be 1 inch outside diameter with 1/16 in walls (or 7/8 in. inside diameter). Entering circulating water velocity is to be 6 ft/s. steam enters the condenser at a rate of 100,000 lb/hr at a pressure of one psia and an enthalpy of 1090 Btu/lb. condensate leaves at saturated liquid at one psia. Circulating water enters the condensate at 85 deg. F and leaves at 95 deg. F. Note: 1 psia condensate has temperature of 101.7 deg. F. wet steam entering becomes condensate at 101.7 deg. F with hf = 69.72 Btu/lb. calculate the total number of tubes to be used in each passes.

A. 18,200 tubes C. 10,450 tubesB. 15,400 tubes D. 11,456 tubes

A

Determine the approximate load on a cooling tower if the entering and leaving temperatures are 96°F and 88°F, respectively and the flow rate of the water over the tower is 30 gpm.

A. 2500 Btu/min C. 3000 Btu/minB. 2000 Btu/min D. 3500 Btu/min

B

Determine the quantity of water lost by bleed off if the water flow rate over the tower 30 gpm and the range is 10°F. Percent bleed-off requires 33%.

A. 0.077 gpm C. 0.099 gpmB. 0.088 gpm D. 0.066 gpm

C

How many tons of refrigeration is required to produce 10 metric tons of ice per day at -10°C from raw water at 22°C if miscellaneous losses are 15% of the chilling and freezing load?

A. 17 TOR C. 15 TORB. 20 TOR D. 24 TOR

A

Refrigeration is 2 m high, 1.2 m wide and 1 m deep. The over-all heat transfer coefficient is o.532 W/m2 °C. how many kilograms of 0°C ice will melt per hour if the inside temperature is maintained at 10°C while the surrounding air temperature is at 35°C?

A. 1.60 kg C. 2.60 kgB. 1.80 kg D. 2.80 kg

A

Determine the heat extracted from 2000 kg of water from 25°C to ice -10°C.

A. 621,150 kJ C. 821,150 kJB. 721,150 kJ D. 921,150 kJ

D

How many independent properties are required to completely fix the equilibrium state of a pure gaseous compound?

A. 1 C. 2B. 3 D. 4

C

Calculate the heat transfer per hour through a solid brick wall 6 m long, 2.9 m high, and 225 mm thick, when the outer surface is at 5°C and the inner surface at 17°C, the coefficient of thermal conductivity of the brick being 0.6 W/m-K.

A. 2,004.48 kJ C. 2,400.48 kJB. 3,004.48 kJ D. 3,400.48 kJ

A

A vertical furnace wall is made up of an inner wall of firebrick 20 cm thick followed by insulating brick 15 cm thick and an outer wall of steel 1 cm thick. The surface temperature of the wall adjacent to the combustion chamber is 1200°C while that of the outer surface of steel is 50°C. The thermal conductivities of the wall material in W/m-K are; firebrick, 10; insulating brick, 0.26; and steel, 45. Neglecting the film resistance and contact resistance of joints, determine the heat loss per sq.m. Of the wall area.

A. 1.93 W/m2 C. 1.55 W/m2

B. 2.93 W/m2 D. 2.55 W/m2

A

A composite wall is made up of an external thickness of brickwork 110 mm thick inside which is a layer of fiberglass 75 mm thick. The fiberglass is faced internally by an insulating board 25 mm thick. The coefficients of thermal conductivity for the three are as follows:

Brickwork 1.5 W/m-KFiberglass 0.04 W/m-KInsulating board 0.06 W/m-k

The surface transfer coefficient of the inside wall is 3.1 W/m2-K while that of the outside wall is 2.5 W/m2-K. Take the internal ambient temperature as 10°C and the external temperature is 27°C. Determine the heat loss through such wall 6 m high and 10 m long.

A. 330.10 W C. 430.10 WB. 230.10 W D. 530.10 W

A

One insulated wall of a cold-storage compartment is 8 m long by 2.5 m high and consist of an outer steel plate 18 mm thick. An inner wood wall 22.5 mm thick, the steel and wood are 90 mm apart to form a cavity which is filled with cork. If the temperature drop across the extreme faces of the composite wall is 15°C. Calculate the heat transfer per hour through the wall and the temperature drop across the thickness of the cork. Take the coefficients of thermal conductivity for steel, cork and wood as 45, 0.045, and 0.18 W/m-K respectively.

A. 408.24 kJ, 12.12°C C. 608.24 kJ, 13.12°CB. 708.24 kJ, 11.12°C D. 508.24 kJ, 14.12°C

D

One side of refrigerated cold chamber is 6 m long by 3.7 m high and consist 168 mm thickness of cork between outer and inner walls of wood. The outer wood wall is 30 mm thick and its outside face temperature is 20°C, the inner wood wall 35 mm thick and its inside face temperature is -3°C. taking the coefficient of thermal conductivity of cork and wood 0.42 and 0.20 W/m-k respectively, calculate the heat transfer per second per sq. m of surface area.

A. 5.138 J C. 6.318 JB. 4.138 J D. 3.318 J

B

Hot gases at 280°C flow on one side of a metal of 10mm thickness and air at 35°C flows on the other side. The heat transfer coefficient of the gasses is 31.5 W/m2-K and that of the air is 32 W/m2-K. Calculate the over-all transfer coefficient.

A. 15.82 W/m2-K C. 14.82 W/m2-KB. 16.82 W/m2-K D. 17.82 W/m2-K

A

The surface temperature of the hot side of the furnace wall is 1200°C.it is desired to maintain the outside of the wall at 38°C. A 152 mm of refractory silica is used adjacent to the combustion chamber and 10 mm of steel covers the outside. What thickness of insulating brick is necessary between refractory and steel, if the heat loss should be kept at 788 W/m2, and 45 for steel.

A. 220 mm C. 260 mmB. 240 mm D. 280 mm

A

A hollow sphere has an outside radius of 1 m and is made of polystyrene foam with a thickness of 1 cm. a heat source inside keeps the inner surface 5.20°C hotter than the outside surface? The thermal conductivity of polystyrene foam is 0.033 W/m°C.

A. 200 W C. 300 WB. 216 W D. 316 W

B

An insulated steam pipe located where the ambient temperature is 32°C, has an inside diameter of 50 mm with 10 mm thick wall. The outside diameter of the corrugated asbestos insulation is 125 mm and the surface coefficient of still air is, ho = 12 W/m2-K. Inside the pipe is steam having a temperature of 150°C with film coefficient hi = 6000 W/m2-K. Thermal conductivity of pipe and asbestos insulation are 45 and 0.12 W/m2-K respectively. Determine the heat loss per unit length of pipe.

A. 110 W C. 130 WB. 120 W D. 140 W

BHow many watts will be radiated from s spherical black body 15 cm diameter at a temperature of 800°C?

A. 5.34 kW C. 6.34 kWB. 4.34 kW D. 3.34 kW

A

A wall with an area of 10 m2 cm thickness of white pine (k = 0.113 W/m°C) followed by 10 cm of brick (k = 0.649°C W/m°C). The pine is on the inside where the temperature is 10°C. Assuming equilibrium conditions exist, what is the temperature at the interface between the two metals?

A. 15.65°C C. 18.21°CB. 17.64°C D. 19.31°C

D

A counter flow heat exchanger is designed to heat fuel oil from 45°C to 100°C while the heating fluid enters at 150°Cvand leaves at 115°C. Calculate the arithmetic mean temperature difference?

A. 40°C C. 60°CB. 50°C D. 70°C

C

A pipe with an outside diameter of 2.5 in. is insulated with a 2 in layer of asbestos (ka = 0.396 Btu/in./hr-ft2-°F). If the temperature of cork 1.5 in. thick (kc = 0.30 Btu/in./hr-ft2-°F). If the temperature of the outer surface of the cork is 90°F, calculate the heat loss per 100 ft of insulated pipe.

A. 847.64 Btu/hr C. 2847.42 Btu/hrB. 3847.51 Btu/hr D. 1847.14 Btu/hr

C

The journals of a shaft are 380 mm diameter, it runs at 105 rpm and the coefficient of friction between journals and bearings is 0.02. If the average load on the bearing is 200 KN, find the heat generated per minute at the bearing?

A. 501.375 kJ C. 401.375 kJB. 505.575 kJ D. 501.575 kJ

A

The flow energy of 124 liters per minute of a fluid passing a boundary to a system is 108.5 kJ/min. determine the pressure at this point.

A. 875 kPa C. 975 kPaB. 675 kPa D. 575 kPa

A

Work done by a substance in reversible non flow manner in accordance with V = 100/P ft3, where P is in psia. Evaluate the work done on or by the substance as the pressure increases from 10 psia to 100 psia.

A. 33,157.22 ft-lb C. 43,157.22 ft-lbB. -33,157.22 ft-lb D. -43,157.22 ft-lb

B

Calculate the change in enthalpy as 1 kg of nitrogen is heated from 1000 K to 1500 K, assuming the nitrogen is an ideal gas at a constant pressure. The temperature dependent specific heat of nitrogen is Cp = 39.06 – 512.79 T1.5 + 1072.7 T2 – 820.4T3 where Cp

is in kJ/kg-mol, T is in K.A. 600 kJ C. 800 kJB. 697.27 kJ D. 897.27 kJ

B

One kilogram of wet steam at a pressure of 8 bar (Vg = 0.2404 m3/kg, vf = 0.0011148 m3/kg) and dryness 0.94 is expanded until the pressure is 4 bar (vg = 0.4625 m3/kg, vf = 0.0010836 m3). If the expansion follows the law PVn = C, where n =1.12, find the dryness fraction of the steam at the lower pressure.

A. 0.9072 C. 0.2260B. 0.4197 D. 0.2404

C

Wet saturated steam at 16 bar (hf = 859 kJ/kg , hg = 1935 kJ/kg) reducing valve and is throttled to a pressure of 8 bar (hr = 721 kJ/kg, hfg = 2048 kJ/kg). Find the dryness fraction of the reduces pressure steam.

A. 0.8833 C. 0.9933B. 0.7733 D. 0.6633

C

A 650 BHP diesel engine uses fuel oil of 28°API gravity, fuel consumption is 0.65 lb/BHP-hr. cost of fuel is P 7.95 per liter. For continuous operation, determine the minimum volume of cubical day tank in cm3, ambient temperature is 45°C.

A. 4,372,890 cm3 C. 5,291,880 cm3

B. 5,987,909 cm3 D. 7,352,789 cm3

A

A typical industrial fuel oil, C16H32 with 20% excess air by weight. Assuming complete oxidation of the fuel, calculate the actual air-fuel ratio by weight.

A. 17.56 kgair/kgfuel C. 16.75 kgair/kgfuelB. 15.76 kgair/kgfuel D. 17.65 kgair/kgfuel

A