Air in an ideal Diesel cycle is compressed from 3 L to 0.15 L and then it expands during the constant pressure heat addition process to 0.3 L. Under cold air standard conditions, the thermal effieciency of this cycle is?

Helium gas in an ideal Otto cycle is compressed from 20°C and 2 L to 0.25 L and its temperature increases by an additional 800°C during the heat addition process. The temperature of Helium before the expansion process is?

In an ideal Otto cycle, air is compressed from 1.20 kg/m3 and 2.2 L to 0.26 L and the net work output of the cycle is 440 kJ/kg. The mean effective pressure for the cycle is?

An ideal Brayton cycle has a net work output of 150 kJ/kg and backwork ratio of 0.4. if both the turbine and the compressor had an isentropic efficiency of 80%, the net work output of the cycle would be?

Air enters a turbojet engine at 200 m/s at a rate of 20 kg/s and exits at 800 m/s relative to the aircraft. The thrust developed by the engine is?

A thermal power has a net power of 10 MW. The backwork ratio of the plant is 0.005. Determine the compressor work.

A heat engine receives heat from a source at 1200 K at a rate of 500 kJ/s and rejects the wasted heat to a sink at 300 K. If the power output of the engine is 200 kW, the second law efficiency of this heat engine is?

A water reservoir contains 100,000 kg of water at an average elevation of 60 m. The maximum amount of electric power that can be generated from this water is ?

A house is maintained at 22°C in winter by electric resistance heaters. If the outdoor temperature is 5°C, the second law efficiency of the resistance heaters is ?

A thermoelectric refrigerator that resembles a small ice chest is powered by a car battery, and has a COP of 0.10. If the refrigerator cools a 0.350 L canned drink from 20°C to 4°C in 30 min, determine the average electric power consumed by the thermoelectric refrigerator.

A Carnot refrigerator operates in a room in which the temperature is 25°C and consumes 2 kW of power when operating. If the food compartment of the refrigerator is to be maintained at 3°C, determine the rate of heat removal from the food compartment.

A household refrigerator with EER 8.0 removes heat from the refrigerated space at a rate of 90 kJ/min. Determine the rate of heat transfer to the kitchen air.

An air-conditioning system is used to maintain a house at 75°F when the temperature outside is 95°F. The house is gaining the heat through the walls and windows at a rate of 1250 Btu/min, and the heat generation rate within the house from people, lights, and appliances amounts to 350 Btu/min. Determine the minimum power input required for this airconditioning system.

A refrigeration system is to cool bread loaves with an average mass of 450 g from 22°C to - 10°C at a rate of 500 loaves per hour by refrigerated air. Taking the average specific and latent heats of bread to be 2.93 kJ/kg-°C and 109.3 kJ/kg, respectively, determine the product load.

A house that was heated by electric resistance heaters consumed 1200 kWh of electric energy in a winter month. If this house were heated instead by a heat pump that has an average performance factor, PF of 2.4, determine how much money the homeowner would be saved that month. Assume a price of 0.085 $/kWh for electricity.

An ammonia simple saturation cycle operates with a suction pressure of 291.6 kPa and a condenser pressure of 1204 kPa develops 15 tons of refrigeration. Determine the theoretical horsepower of the compressor. The following enthalpies have been found: condenser entrance = 1653 kJ/kg, exit = 346.6 kJ/kg; compressor entrance = 1450.2 kJ/kg, exit = 1653 kJ/kg.

An ammonia ice plant operates between a condenser temperature of 35°C and evaporator of -15°C. It produces 10 metric tons of ice per day from water at 30°C to ice at -5°C. Assuming simple saturation cycle, determine the horsepower of the motor if the adiabatic efficiency of the compressor nc = 0.85 and mechanical efficiency nm = 0.95. The specific heat of ice is 2.094 kJ/kg-°C and the latent heat is 335 kJ/kg. From the table for ammonia the following enthalpies are: condenser entrance = 1703 kJ/kg, exit = 366.1 kJ/kg; compressor entrance = 1443.9 kJ/kg, exit = 1703 kJ/kg.

A Freon 22 air conditioning under standard operating conditions of 35°C condensing and 5°C evaporating temperatures. The volume flow rate entering the compressor is 23.72 L/s. Determine the refrigerating capacityif the refrigerating effect is 164 kJ/kg. From the table for R22 the specific volume at the compressor entrance is 40.46 L/kg.

The refrigerant volume flow rate at the entrance of compressor were obtained from a test on a twin cylinder, single acting 15 cm x 20 cm, 320 rpm compressor ammonia refrigerating plant to be 33 L/s. Determine the volumetric efficiency of the compressor.

A twin cylinder ammonia compressor with volume displacement of 14,726 cm3 operates at 300 rpm. Condenser and evaporator pressure are 1200 kPa and 227 kPa respectively. Specific volume of refrigerant at the entrance of compressor is 528.26 L/kg. Compression process is polytropic with n = 1.20 and clearance factor of compressor is 2 percent. Determine the horsepower required.

A reversed Carnot has a refrigerating COP of 2.5. Determine the ratio TH/TL

Three thousand cubic feet per minute of air are circulated over an air-cooled condenser. If the load on the condenser is 64,800 Btu/hr, compute the temperature rise of the air passing over the condenser. Specific volume of standard air (13.34 ft3 /lb).

Saturated vapor ammonia at -16°C (hT = 1442.60 kJ/kg) leaves the evaporator and enters the compressor at -6°C (h1 = 1465 kJ/kg). The refrigerant leaves the condenser as saturated liquid at 40°C (h4 = 390.6 kJ/kg) and enters the expansion valve at 35°C (h5 = 366.1 kJ/kg). Heat rejected from the condenser amount to 50 kW. The work to compressor is 208 kJ/kg, while the heat loss from compressor is 33 kJ/kg. If 95 kJ/kg of heat are lost in the piping between the compressor discharge and condenser inlet, determine the refrigerating capacity of the system.

In an actual refrigeration cycle using R12 as working fluid, the refrigerant flow rate is 0.05 kg/s. Vapor enters the expansion valve at 1.15 MPa, 40°C (h = 238.5 kJ/kg) and leaves the evaporator at 175 kPa, -15°C (h = 345 kJ/kg). The electric iput to motor driving the compressor is measured and found 3.0 kW. Motor efficiency at this load 92% and mechanical efficiency 82%. Determine the actual coefficient of performance for this cycle.

In an ammonia refrigeration system, the temperature in the evaporator is -12°C and the ammonia at the evaporator entry 0.1511 dry while at exit is 0.95 dry. If the rate of ammonia circulation is 5.64 kg/min, determine the refrigerating capacity of the system. Enthalpy of saturated liquid and vapor at -12°C is 144.929 kJ/kg and 1447.74 kJ/kg respectively.

A two stage cascade vapor compression refrigeration system uses ammonia in the lowtemperature loop and R-12 in the high-temperature loop. The ammonia provides 15 tons of cooling. If the high-loop temperature requires 10.12 kW compressor power and low loop 15.93 kW, determine the COP of the system.

When a man returns to his well-sealed house on a summer day, he finds that the house is at 32°C. He turns on the air conditioner, which cools the entire house to 20°C in 15 min. If COP of the air conditioner system is 2.5, determine the power drawn by the air conditioners. Assume the entire mass within the house is equivalent to 800 kg of air for which c = 0.72 kJ/kg - °C

It is desired to double the COP of a reversed Carnot engine for cooling from 5.0 by raising the temperature of heat addition while keeping the temperature of heat rejection constant. By what percentage must the temperature of heat addition be raised?

An ammonia water-cooled compressor receives the refrigerant at specific volume 62 L/kg. It has a piston displacement rate of 5 m3/min. If a squirrel cage motor running at 1200 rpm drives the compressor and average piston speed is 490 m/min, calculate size of cylinder bore.

f the initial volume of an ideal gas is compressed the one-half its original volume and to twice its temperature, the pressure:

If the gage pressure of a medium is 30 kPa (vacuum) and the atmospheric pressure is 101.3 kPa, the absolute pressure will be?

If a particle has a velocity of 4 meters per second and a kinetic energy of 144 Joules, then the mass, in kilograms of this particle must be?

A condenser vacuum gauge reads 715 mm Hg when the barometer stands at 757 mm Hg. State the absolute pressure in the condenser in kN/m2 or kPa.

Determine the force in newton in a piston of 465 mm2 area with a pressure of 0.172 MPa.

One piston of a hydraulic press has an area of 1 cm2. The other piston has an area of 25 cm2. If a force of 150 N is applied on the smaller piston, what will be the total force on the larger piston if both piston surfaces are on the same level?

The work done on air is 10.86 kJ/kg, determine the compressor power if it is receiving 272 kg/min of air

A water tank 18 ft wide, 14 ft long, and 4 ft high, calculate the pressure at the bottom of the tank.

What is the pressure of 750 mm Hg in kN/m2?

A double purpose tank 18 ft wide, 24 ft long and 4 ft depth is filled with water. What is the weight of water in the tank in long tons?

Oil flows through a 16 tube single cooler with a velocity of 2 m/s. The internal diameter of the tube is 30 mm and oil density is 0.85 gm/ml. Find the volume flow in liters per sec.

A substance temperature was 620°R. What is the temperature in °C?

An unknown volume of container gas of 1 atmosphere is allowed to expand to another container of 10 m3 volume at 500 mmHg at constant temperature. Find the unknown volume.

An iron block weighs 5 Newton and has a volume of 200 cm3. What is the density of the block?

If air is at a pressure of 22.22 psia and at a temperature of 800°R, what is the specific volume?

The Specific gravity of mercury is 13.55. What is the specific weight of mercury?

The equivalent weight of mass 10 kg at a location where the acceleration of gravity is 9.77 m/s2?

A transportation company specializes in the shipment of pressurized gaseous materials. An order is received from 100 liters of a particular gas at STP (32°F and 1 atm). What minimum volume tank is necessary to transport the gas at 80°F and maximum pressure of 8 atm?

100 g of water are mixed with 150 g of alcohol (density = 790 kg/m3). What is the specific volume of the resulting mixtures, assuming that the fluids mixed completely?

How much does 30 lbm weigh on the moon? (gmoon = 5.47 ft/s2).

A 10 kg block is raised vertically 3 meters. What is the change in potential energy?

How many cubic meters is 100 gallons of liquid?

Steam turbine is receiving 1014 lbm/hr of steam, determine the horsepower output of the turbine if the work done by steam is 251 Btu/lbm.

What is the resulting pressure when one pound of air at 15 psia and 200°F is heated at constant volume to 800°F?

A bicycle tire has a volume of 600 cm3. It is inflated with carbon dioxide to pressure of 551.43 kPa, 20°C. How many grams of CO2 are contained in the tire? RCO2 = 0.18896 kJ/kg.K.

The absolute pressure at the bottom of a vertical column of water is 15.5 psia. What is the height of this column?

A water temperature rise of 18°F in the water cooled condenser is equivalent to what in °C?

An oil storage tank contains oil with specific gravity of 0.88 and depth of 20 meters. What is the hydrostatic pressure at the bottom of the tank in kg/cm2?

A vertical column of water will be supported to what height by standard atmospheric pressure?

The specific weight of liquid is 60 lb/ft3. What is the equivalent to kN/m3?

A cylinder weighs 150 lbf. Its cross-sectional area is 40 square inches. When the cylinder stands vertically on one end, what pressure does the cylinder exert on the floor?

What is the absolute pressure exerted on the surface of a submarine cruising 300 ft below the free surface of the sea? Assume specific gravity of sea water is 1.03.

Air enters a nozzle steadily at 2.21 kg/m3 and 30 m/s. What is the mass flow rate through the nozzle if the inlet area of the nozzle is 80 cm2?

What is the work required to accelerate an 800-kg car from rest to 100 km/h on a level road?

Assuming that there are no heat effects and no friction effects, find the speed of a 3220-lbm body after it falls 778 ft from rest.

What is the flow rate through a pipe 4 inches in diameter carrying water at a velocity of 11 ft/s?

If the specific weight of a liquid is 58.5 lbf per cubic foot, what is the specific volume of the liquid in cm3/g?

What is the resulting pressure when one pound of air at 0.3 psig and 200°F is heated at constant volume to 800°F?

A small pump serving as model, when tested in laboratory using water at 3600 rpm, delivered 30 cfs at a head of 125 ft. If the efficiency of this model pump is 84%, predict the horsepower input to the prototype pump if it is to develop the same head as model pump and the model pump has a scale ratio of 1:10. Assume the efficiency of the prototype pump is 90%.

Pump at is best efficiency point (BEP) has a capacity of 10,500 gpm while developing a head of 60 ft at a rotative speed of 1450 rpm. What is the specific speed of the pump?

A pump will be installed below the reservoir water surface with a required net positive suction head (NPSHR) of 50 ft. The barometric pressure is 14.3 psia, and the vapor pressure is 0.5 psia. Assume friction losses in the intake piping are 5 ft. Find the maximum allowable elevation of the pump relative to the water surface intake to avoid cavitation.

A centrifugal pump is at best efficiency point (BEP). Assume the pump characteristic are head, h = 7 m, flow rate, Q = 19 liters/s, and rotative speed n = 1170 rpm. Find the specific speed in SI units.

The pressure of a confined gas at a constant temperature is tripled, what will happen to the volume?

A 15 in. diameter fan operates at 1600 rpm and develops a head of 6 in. of water and delivers 120 cfm. What volumetric capacity for geometrically similar fan will develop 6 in of water at 1300 rpm?

A radial-flow pump operating at maximum efficiency at a specific speed of 2500 is to deliver 260 gpm against a head of 129 ft at a rotative speed of 2100 rpm. Find the required number of stages (i.e., impellers).

How many identical turbines, operating at 139.0 rpm and 91% efficiency (specific speed = 5.4), are needed to exploit a head of 1200 ft and a flow of 1660 ft3/s?

How many poles should a 60-Hz generator have, if it is connected to a turbine operating under a design head of 3000 ft with a flow of 82 cfs? Assume turbine specific speed and efficiency 3 and 84 percent respectively.

It is proposed to build a dam in a river where the flow rate is 10 m3/s and a 32-m drop in elevation can be achieved for flow through a turbine. If a turbine is 82 percent efficient, what is the maximum power that can be achieved? Specific gravity of river is 0.998.

What type of turbine delivers 25,000 bhp at 500 rpm under a net head of 5350 ft?

A 26-hp pump delivers 475 gpm of gasoline (γ = 42.5 lb/ ft3) at 20 C with 78% efficiency. What pressure rise result across the pump?

A model pump delivering water at 180°F (γ = 60.6 lb/ ft3; pvapor = 7.54 psia) at 900 gpm and 2500 rpm begins to cavitate when the inlet pressure and velocity are 13 psia and 22 fps. Find the required NPSH of a prototype which is 4 times larger and runs at 1100 rpm.

The diameter of the discharge pipe is 8 in. and that of the intake pipe is 10 in. The pressure gage at discharge reads 32 psi, and vacuum gage at the intake reads 12 in. Hg. If the discharge flow rate = 4.0 ft3 /s of water and the brake horsepower is 49.0, find the efficiency. The intake and the discharge are at the same elevation.

A piston positive-displacement pump (PDP) has a 6-in diameter and a 2.5-in stroke. Its crankshaft rotates at 300 rpm. Calculate its output at 94 percent volumetric efficiency.

A centrifugal pump (efficiency 88%) lifts water through a total height of 40 m from a reservoir to discharge. Pumping is through 300 m of 75 mm diameter pipe at the rate of 20 liter/s. If pipe friction, f = 0.025, what horsepower is required?

In order to predict the behaviour of a small oil pump, tests are to be made on a model using air. The pump is to be driven by a 1/20-hp motor at 1800 rpm and a ¼-hp motor is available to drive the air at 600 rpm. Using specific gravity of oil at 0.912 and density of air constant at 0.076 lb/ ft3, what size model should be built?

A double-overhung impulse turbine installation is to develop 20,000 hp at 275 rpm under a net head of 1100 ft. Determine the specific speed.

An impulse wheel at best produces 125 hp under a head of 210 ft. By what percent should the speed be increased for a 290-ft head?

What is the power ratio of a pump and its 1/5 scale model if the ratio of heads is 4 to 1?

The speed of a centrifugal pump is doubled. By what factor does the pump head change?

Compute the specific volume of an air-vapor mixture in cubic meter per kg of dry air when the following conditions prevail: t = 40°C, w = 0.015 kg/kg, and Pt = 90 kPa.

A coil has an inlet temperature of 70°F and outlet of 80°F. If the mean temperature of the coil is 130°F, find the bypass factor of the coil.

Compute the pressure drop of 35°C air flowing with a mean velocity of 5m/s in a circular sheet-metal duct 400mm in diameter and 25 m long. Use friction factor, f = 0.04, and ρair = 1.3799 kg/m3.

Pressure difference of 400 Pa is available to force 20°C air through a circular sheet-metal duct 450 mm in diameter and 25 m long. At 20°C, ρ = 1.204 kg/m3 and take friction factor, f = 0.016. Determine the velocity

A rectangular duct has a dimension of 0.25 m by 2 m. Determine the equivalent diameter of the duct.

To what height will a barometer column rise if the atmospheric conditions are 13.9 psia and 68°F and barometer fluid is mercury?

To what height will a barometer column rise if the atmospheric conditions are 13.9 psia and 68°F and barometer fluid is ethyl alcohol? Note: @ 68°F; Pv =138.5 lbf/ft3 and specific gravity of 0.79 for ethyl alcohol:

What is the pressure 7000 ft below the water surface of the ocean? Neglect compressibility.

If atmospheric air 14.7 psia and 60°F at sea level, what is the pressure at 14212 ft altitude if air is incompressible? Note: @ 60°F, the density of air is 0.0763 lbm/ft3 ; P1 = 14.7 psia.

Water (ρ = 62.4 lbm/ft3) is flowing through a pipe. A pitot-static gage registers 3.0 inches of mercury. What is the velocity of the water in the pipe? Note: ρHg = 848.6 lbm/ft3.

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