What is the power generated by a micro-hydropower plant having a gross head of 80 meters and reliable discharge of 50 liters/second. Assume typical efficiency

Give the estimated mechanical power output of a windmill having a rotor diameter of 8 meters if wind velocity is 3 m/s

What is the electrical energy consumption of a 10-kw coconut oil expeller plugged in a 220-volt source if it requires 3 hours to expel oil from 1,000 kg of grated copra?

What is the peak solar power generation per charging channel of a solar battery charging station equipped with 12 units of 75 watt-peak 12-volt solar module? The system is divided into 3 charging channels, each channel has 4 modules connected in parallel. Assume 80% overall efficiency

An industrial heater has 8 pieces heating plates of 6 ohms each. Plates are arranged in series. If the heater power source is from a 220-volt outlet, how much current will flow?

How much should be budgeted annually for the electrical consumption of a 20-kw coconut oil expeller drawing 92 amperes current and having an electrical consumption of 0.04 kwh/kg copra? It expels 250 kg of copra per hour and operates 16 h/day at 264 days/year. Electricity costs PHP5/kwh. Use 10% cost safety factor

What is the peak amperage of a solar battery charging station equipped with 16 units of 75 watt-peak 4.16-ampere solar module? The system is divided into 4 charging channels, each channel has 4 modules connected in parallel

What is the system voltage of a solar pumping system equipped with 2 units of 75 watt-peak solar modules? Each solar module has 4.16 amperes maximum, open circuit voltage of 21 volts maximum and nominal voltage of 12 volts. Modules are connected in series

Estimate the hydraulic power output of a multi-bladed windmill when windspeed is 3 m/s. It has 0.3 rotor power coefficient, 90% transmission efficiency, 90% pump volumetric efficiency and 6 meters rotor diameter. Air density is 1.2 kg/m3

If a 10-meter high multi-bladed windmill for vegetable farm has a minimum running windspeed of 1.5 m/s, what is the minimum windspeed for the rotor to start turning?

A horizontal-axis windmill for poultry farm water pumping has a rotor diameter of 8 meters and registers a running torque of 920 Newton-meters. What is the torque needed to start its rotor turning?

How many 75 watt-peak solar modules are needed for a solar powered incubator having a power rating of 144 watts, system voltage of 48 volts and amperage of 6 amperes? All solar modules used have 12 volts nominal voltage and 4.6 amperes peak amperage

What should be the tilt angle from the horizontal of the glass solar collector of a hybrid biomass-solar dryer located somewhere in Surigao, Philippines, having a longitude of 125 degrees and latitude of 9 degrees? Since Philippines is in northern hemisphere, the solar collector faces south or opposite hemisphere for maximum energy collection

Geothermal, biodiesel and windfarm renewable energy projects are evaluated for financial feasibility but only a maximum of 2 projects can be implemented. Each of them requires PHP900,000,000 investment. The financial internal rate of return (IRR) are 28.2%, 9.8% and 9.6% for geothermal, biodiesel and wind project, respectively. Annual money discount and inflation rate is 10.2%. Which project shall not be implemented?

Determine the biogas consumption per day of a household using a 4-inch gas burner at 4 hours duration per day. The gas consumption of the burner is constant at 0.283 m3/hour

Determine the biogas production per day of an animal farm having 10,000 heads of porkers of mixed ages. Use a retention period of 35 days. The mean daily manure production of porkers is 2.2 kg/head while the specific gas production for 35-day hydraulic retention time in the digester is 0.065 m3/kg

How many heads of breeding buffalo are needed as source of manure to generate 1,000 m3 of biogas a day if the retention period is 25 days. The mean daily manure production of breeding buffalo is 13.5 kg/head while its specific gas production for 25-day manure retention period is half of that of chicken dung

Determine the required digester volume of a biogas plant that will accommodate manure from a broiler farm having a capacity of 20,000 heads of mixed ages. Use 30-day retention period and 1:1 manure-water ratio. The mean daily manure production of broiler is 0.025 kg/head while its specific gas production for 30-day manure retention period is 0.062 m3/kg. Chicken dung density is 950 kg/m3

A special electric motor required 1.962 kW and 9.5 amperes from a given voltage source of 220 V with 50 Hz frequency. What is the power factor of the motor

An induction motor draws 7.6 A from a 220-V 60-Hz single-phase voltage supply. To improve the power factor of an induction motor from 0.787 to 1.0, the size of the parallel connected capacitor should be

Engr. Salvanera and Engr. Opiña were asked by Dean Pabustan to design 6 pcs. of work benches for the AE REVIEW 2020. The engineers found out that they needed 12 pcs. of 2”x3”x12’ and 8 pcs. of 2”x2”x12’ for each work bench. How many board feet of lumber would they need for all the benches?

200 lux is equivalent to

A motorist equips his automobile tires with a relief-type valve so that the pressure inside the tire never will exceed 240 kPa (gage). He starts a trip with a pressure of 200 kPa (gage) and a temperature of 23OC in the tires. During the long drive, the temperature of the air in the tires reaches 83OC. Each tire contains 0.11 kg of air. Determine the mass of air escaping each tire

Three circuit components namely, 0.075 Henry inductor, 21 ohm resistor, and 415 microFarad capacitor are connected in series. Calculate the total impedance of the circuit if the source frequency is 60 Hz

The axle of a heavy duty tractor transmit 120 kW at 600 rpm at the same time supports a load as a cantilever carrying 280 N located 60 cm from the support. The allowable normal stress is 137 MPa and allowable shear stress is 62 MPa. If the axial forces are negligible, find the axle diameter

When connected at 120-Volts, 60-Hz power line, a load absorbs 4 kW at a lagging power factor of 0.8. The value of capacitance necessary to raise the pf to 0.95 is

If 200 kg of shelled corn at 32% moisture content are dried to 19% moisture content, how much moisture is taken out?

For an 8-A current to produce 10-C charge, how much time is needed?

76 mm solid shaft is to be replaced by a hollow shaft of equal torsional strength. Find the inside diameter if the outside diameter of the hollow shaft is 100 mm and how much weight is saved?

How much energy is needed for a 5-volt source to move 4 coulombs of charge?

A cubical tank of 3 m sides is constructed of metal plate 12 mm thick and contains water at 60OC. Calculate the heat transfer (in kJ/min) if the surrounding air temperature is 20OC, the coefficient of thermal conductivity of the metal is 48 W/m-K, and the film coefficient of heat transfer of air is 16 W/m2-K

Five hundred cubic centimeters of a gas at 22OC and 760 mm Hg absolute undergoes a process until the temperature drops to 8OC and the pressure 800 mm Hg. How much is the volume reduction?

A wooden pole (SG=0.65), 9 cm by 9 cm by 5 m long, hangs vertically from a string in such a way that 3 m is submerged in water and 2 m is above the surface. What is the tension in the string?

Two resistances of 2 ohms each is connected in series to a parallel connection of two 5-ohm resistances and a 10-ohm resistance. What is the equivalent resistance?

At what speed will a 14-pole, 60-cycle induction motor operate if the slip is 0.09?

A motor draws 10 A from a 220-V supply at a power factor of 0.75. If the power delivered is 1.4 hp, what is the efficiency of the motor?

A reversed Carnot cycle has refrigerating COP of 4. The work done on the cycle is 10 hp. Determine the ratio T2/T1

A reversed Carnot cycle has refrigerating COP of 4. The work done on the cycle is 10 hp. Determine the maximum refrigerating effect in tons

A reversed Carnot cycle has refrigerating COP of 4. The work done on the cycle is 10 hp. If the cycle is used as heat pump, determine the COP

A special electric rate for heating water is allowed, in which case the energy is metered away separately. The rate is 1 peso/kW-hr for the first 75 kW-hr and 1 cent/kW-hr for all over 75. The energy recorded by the regular meter costs 5 pesos/ kW-hr for the first 200 kW-hr and 1 cent/kW-hr for all over 200. A family normally uses 300 kW-hr for general applications and 300 kW-hr for water-heating. How much shall be paid on the electrical consumption for the two-meter system, the one used to gain the special rate?

A special electric rate for heating water is allowed, in which case the energy is metered away separately. The rate is 1 peso/kW-hr for the first 75 kW-hr and 1 cent/kW-hr for all over 75. The energy recorded by the regular meter costs 5 pesos/ kW-hr for the first 200 kW-hr and 1 cent/kW-hr for all over 200. A family normally uses 300 kW-hr for general applications and 300 kW-hr for water-heating. Which metering system should be the advantage of the customer – the one meter for everything, or the two meters – and by how much?

What is the total VA rating of a 220-V, 3-phase circuit supplied by a 20- A, 3-pole circuit breaker?

Calculate the quantity of heat energy required to boil 10 kilograms of water from an initial temperature of 23 degree C

The factor kn for a certain kW-hr motor is 2.0, and the disk makes 40 rev. in 10 min. How many kilowatt-hours will be used if the appliances attached to the motor were on for 8 hours?

Gas is flowing through a square conduit whose section gradually changes from 150 mm (section 1) to 300 mm (section 2). At section 1, the velocity of flow is 7 m/s and the density of gas is 1 kg/m3 while at section 2 the velocity of flow is 2 m/s. What is the density at section 2?

If the heat generated during composting is 5.0 MJ/kg , what is the equivalent compost temperature at airflow of 90 m3/kg. The air leaving the compost reactor is saturated and its temperature equal to that of compost material. Air enters the reactor at 30°C and 50% RH. Assume ρa of 1.13 kg/m3 and Cp=1.01 kJ/kg-K

A 250-gram sample of grains, oven-dried to constant weight at 212OF, was taken for a screen analysis. The results were as follows. What is the fineness modulus?

A grain material rests on a large pile. If its coefficient of friction is 0.73, what is the angle of repose?

Seventy-five hundred pounds of fresh beef enter a chilling cooler at 102OF and are chilled to 45OF each day. The specific heat of beef before freezing is 0.75 Btu/lbOF, and after freezing is 0.40 Btu/lbOF. Compute the product load in Btu per 24-h

Seventy-five hundred pounds of fresh beef enter a chilling cooler at 102OF and are chilled to 45OF each day. The specific heat of beef before freezing is 0.75 Btu/lbOF, and after freezing is 0.40 Btu/lbOF. Compute the product load in Btu per 24-hr.

A prony-break test of a motor gave the following data: Force = 2 lb N = 1720 rpm Length of arm = 1 ft Electrical meter readings: Current = 11.4 A Voltage=110 V Power = 960 W. What is the actual power delivered by the motor as measured by the prony break test?

A prony-break test of a motor gave the following data: Force = 2 lb N = 1720 rpm Length of arm = 1 ft Electrical meter readings: Current = 11.4 A Voltage=110 V Power = 960 W. What is the efficiency of the motor in converting electric energy to mechanical energy?

A prony-break test of a motor gave the following data: Force = 2 lb N = 1720 rpm Length of arm = 1 ft Electrical meter readings: Current = 11.4 A Voltage=110 V Power = 960 W. What is the power factor?

At an average temperature of 100°C, hot air flows through a 2.5m long tube with an inside diameter of 50mm. The temperature of the tube is 20°C along its length. Convective heat transfer coefficient is 20.1 W/m2∙K. Determine the heat transfer from air to tube

Water at a mean temperature of 120°F flows through a 6.0 inch diameter pipe at a rate of 80 lbm/sec. If the mean temperature of the wall of the pipe is 180°F and if the length of the pipe is 20ft, find the Reynolds number. At 120°F, ρ = 61.73 lbm/ft3, μ = 1.36 lbm/ft∙hr, k = 0.372 Btu/hr∙ft∙°F, cp = 0.997 Btu/lbm∙°F

A farmer would like to cement the flooring of his warehouse with a total volume of 200m3. Determine the material required using 20 liters of water for every bag of cement and a Class C mixture

A farmer would like to cement the flooring of his warehouse with a total volume of 200m3. Determine the material required using 20 liters of water for every bag of cement and a Class C mixture. Determine the required cubic meters of sand

A farmer would like to cement the flooring of his warehouse with a total volume of 200m3. Determine the material required using 20 liters of water for every bag of cement and a Class C mixture

A wooden rectangular frame (1.5 m x 3 m) is to be fabricated using 2” x 2” coco lumber. Compute for the total bdft required for this frame

Determine the quantity of CHB needed for a 16m x 5m (ground line included) wall

Shrimp harvested in a pond situated in Bohol are packed in insulated sheet metal containers and mixed with crushed ice while in transit to the shrimp processing plant in Manila. Initial temperature of the product is about 25°C and it is desired to cool the shrimp at approximately 0°C during shipment. Estimate the product load, in kJ/kg. For shrimp highest freezing temperature is –2.2°C, cp above freezing is 3.38 kJ/kg∙K, cp below freezing is 1.79 kJ/kg∙K, and latent heat of fusion is 254 kJ/kg

Amount of water needed to increase moisture content of 50 kg (fresh weight) manure from 40% (wet basis) to 60% (wet basis)

What would be the temperature of the air leaving the evaporative cooler if outside temperature in the greenhouse is 37°C and the cooler has an efficiency of 90%. Assume wetbulb temperature of 35°C

A block having a weight of 19.62 N is placed on a spring scale located in an elevator that is moving downward. The scale reading is 20 N. What is the acceleration of the elevator?

A rice miller buys 100kg of dried and clean palay at P13/kg. Assuming that his cost of operation is P4/kg milled rice, how much should he sell (P/kg) to break even. Neglect by-products and assume milling recovery of 64%

A Carnot refrigeration cycle absorbs heat at –12°C and rejects it at 35°C. What is the COP of this refrigeration cycle?

When a 2-ohm, a 4-ohm, and a 6-ohm resistors are in delta connection, the equivalent resistors in Wye connection are

How much energy is required to operate an 5 hp motor used every other day for 5 hours and a 500 watt lamp used daily for 4 hours a day, both during a 30-day month?

For a given voltage source of 220 V at 50 Hz, a special electric motor required 1.962 kW and 9.5 amperes. Find the power factor of the motor

What is the magnitude of allowable 2% voltage drop for a 2-wire run with length of 200 meters at 220 volt supply and 8 ampere circuit?

If a product has a percentage moisture content of 12% wet basis, the equivalent percentage moisture content in dry basis is

A capacitance of 50 μF and a resistance of 200 ohms are connected in series across a 220-V, 60 Hz mains. What is the power factor?

A product has a percentage moisture content of 25% expressed in dry basis. What is the percentage moisture content of the product in wet basis?

If a pile of rice is 8-m long, 6-m wide, and 3.6-m high, how many bags of rice are safe to be piled?

The resistivity of a wire is 1.69 × 10-8 ohm-m. If it has a diameter of 0.1 cm, what is its length if the total resistance is 10 ohms

A man would like to build a rectangular room having a 6 m x 4 m x 3m (lw-h) dimension. Estimate the no. of concrete hollow blocks needed (exclude the foundations)

What is the total board foot of 5 pieces of 2-in. x 6-in. x 14-feet wood?

If 20 kg of water is removed from a 110-kg paddy, what is the percentage moisture content of the paddy in wet basis?

A 50-cm long, 0.2-cm diameter electric resistance wire submerged in water is used to determine the boiling heat transfer coefficient in water at 1 atm experimentally. The surface temperature of the wire is measured to be 130degC when a wattmeter indicates the electric power consumption to be 4.1kW. Then the heat transfer coefficient is

Paddy grain with 14% MC wet basis has approximately _____________ MC dry basis

What force is required to punch a 20 mm diameter hole in a plate that is 25 mm thick? The shear strength is 350 MPa

The tensile stress that will be developed if a force of 10 N is applied to one end of a 10 inches diameter circular rod

A thick-walled stainless-steel tube (k = 19 w/m-°C, with 2 cm ID and 4 cm OD) is covered with a 3-cm layer of asbestos insulation (k = 0.2 w/m-°C). If the inside wall temperature of the pipe is maintained at 600°C and the temperature outside of the insulation is at 100°C, what would be the heat loss per foot length of the tube?

What is the theoretical rpm of a bucket elevator whose head pulley diameter is 0.2 m and the bucket projection is 0.1 m?

What is the theoretical rpm of a bucket elevator whose head pulley diameter is 0.2 m and the bucket projection is 0.1 m. If the operational efficiency of the bucket elevator in Item 2 is 85% of the theoretical speed, what is the operation speed of the elevator?

Determine the monthly electrical consumption of a farm residence having the following loads: one 1200-watts electric iron with 2 hours usage; one 1000-watt water heater with 3 hours usage; and one 1300-watt toaster with 30 minutes usage.

What is the theoretical horsepower requirement of a bucket elevator with 545 kg/min capacity and has 10.7 m lift. The elevator is loaded down side.

A 40 watt fluorescent lamp produces 3,000 lumens of light in a room with a dimension of 3 meters by 5 meters. What is the illumination of the floor?

Ten BTU is equivalent to

One-hundred calories is equivalent to

If 5000 bags of palay are to be piled 20-bags high, how many square meters of floor space is required? (0.23 m/bag

What is the peak storage capacity of a 5-m diameter grain storage bin with an average height and a minimum angle of fill of 6 m and 28 deg., respectively?

Suppose that the wooden beam to be used is circular in shape, what will be its section modulus if its diameter is 20 cm?

In an 18-Volt circuit, the current passing through four resistors are 1.6 mA, 0.8 mA, 1.5 mA, and 0.65 mA, respectively. Calculate the total equivalent resistance if the resistors are connected in parallel

A 30 ohm resistor, a 0.095 Henry inductor and a 318 µfarad capacitor are connected in series across a 240 volt 60 Hz supply. What is the total impedance of the circuit?

Compute the input current in a 5-hp electric motor used to drive a hammer mill at 2200 rpm. The input voltage is 220 with 0.98 power factor

Engr. Balalio and Engr. Macaroy were asked by Dean Santos to design 5 pcs. of work benches for the AE REVIEW 2015. The engineers found out that they needed 10 pcs. of 2"x3"xI2' and 6 pcs. of 2"x2"xI2 for each work bench. How many board feet of lumber would they need per piece of workbench?

A 100-watt light bulb is used continuously for 8 hours. How much electric energy is used? If the cost of electricity is P10.00 per kw-hour, how much is the cost for 2-months period at 20 days per month operation?

An electric motor has a nameplate rating of 2 horsepower, 240 volts, and 15 amperes. Calculate the motor power factor assuming an 85% motor efficiency. Also compute for the motor power input.

Determine the monthly energy consumption of a farm house having the following appliances: electric iron, 1200 watts at 2 hours; water heater, 1000 watts at 3 hours; and toaster, 1,300 watts at 30 minutes. If the average cost of energy is P10.00 per kwh, what is the total cost of the energy used in 30-day consumption?

What is the equivalent size in square millimeter of a 250 MCM cable?

What is the percentage moisture reduction per hour if two-ton mechanical dryer dries paddy from 24% to 14% in 8 hours?

A 12-inch diameter fan rotates at a speed of 1800 rpm. The fan blade has a pitch angle of 10 degrees. If the fan has 40% static efficiency, what is its flow rate?

A seed processing warehouse requires 150,000 BTU/hr of refrigeration system to maintain thre required 20 degree C storage temperature. How many tons of refrigeration is required to the warehouse?

What is the drying capacity of the dryer if two-ton mechanical dryer dries paddy from 24% to 14% in 8 hours?

A 2-m x 10-m space is supplied with 400-lux light. How many foot-candle does a lamp provide into the space? Assume a coefficient of utilization of 0.80 and a service factor of 0.76

A rice milling plant is to be designed to run at a throughput rate of 5 tons per hour. The design milling recovery is 69% while the hulling efficiency is 95%. How many compartments are needed for the paddy separator of the rice mill? Assume 50 kg br/hr-compartment

A 4 x 6 rubber roller is used as husker for a rice mill. The faster roller is directly driven by an electric motor at a speed of 1720 rpm. What would be the required speed for the slower roller?

Compute the needed amount of rice hull, in kg, to dry 10000 kg of palay from 30% MC to a minimum required MC for safe storage for 5 months. The latent heat of vaporization is 2, 500 kJ/kg. Assume 100 % efficiency

A man would like to build a rectangular room having a 5 m x 4 m x 3m (lw-h) dimension. Estimate the no. of concrete hollow blocks needed (exclude the foundations)

A rice mill has a throughput rate of 2 tons per hour of input material. If the percent purity of the material is 95% and the hulling efficiency of the hulling unit is 90%, what size of compartment-type separator would your recommend for the rice mill?

Two piles of shelled corn in bags will be stored in a warehouse having a dimension of 15- wide by 30-m long and 6-m high. How many bags of shelled corn could be contained per pile inside the warehouse?

When a 10-ohm, a 20-ohm, and a 30-ohm resistors are connected in parallel, the total equivalent resistance is:

What would be the speed of a 120 V 6-pole motor on a 60 Hz source?

What is the power dissipated when a ½ amp current flows through a 5 ohm resistor?

A 10 ohm resistor is connected in series with a capacitive reactance of 24 ohms. What is the total impedance?

A 10 ohm resistor is connected in parallel with a capacitive reactance of 24 ohms. What is the total impedance?

A vane axial fan of a flat-bed dryer runs at a speed of 800 rpm. The rate of flow of the fan is 100 cfm at a pressure head of 1 in. of water. What is the specific speed of the fan?

A screw conveyor discharges 10 kg per minute of grains on a horizontal position. It consumes 2 hp of power during operation. If the conveyor will be inclined at 45 degree position, what will be its power consumption?

Calculate the thermal conductivity of a 4’ x 8’ test panel, 1-in. thick if during a 3-hour test period it conducted 900 BTU of heat through the panel. With a temp. difference of 15 F between its surfaces

A biomass furnace with 1-in. horizontal-plate steel wall is covered by a 2-in. thick insulation. The temperature of the upper side of the steel wall is 450 F while the lower side of the insulation is 100 F. if the K steel is 29 BTU/hr-ft-F and he K for the insulation is 0.5 BTU/hr-ft-F. What is the temperature at the junction between the steel plate and the insulation?

A screw conveyor discharges grains on a horizontal position at 10 kg per minute. If the conveyor will be inclined at 45 degree position, what is its output in tons per hour?

A swine house, having a dimension of 20-ft wide by 60-ft long, requires an illumination of 200 lux. If a 25-watts fluorescent lamp with lighting intensity of 100lumen is provided, how many bulbs will be needed for the structure?

A 40 watt fluorescent lamp 120cm long produces 3,200 lumens of light in a room having a general dimension of 10 ft x 20 ft. What is the illumination of the floor?