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 1200oC while that of the outer surface of steel is 50oC. The thermal conductivities of the wall material in W/Mk are: firebrick (10), insulating brick (0.26), and steel (45). Determine the heat loss per sq. m. of wall area.

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 coefficient of thermal conductivity for the three are as follows:
The surface transfer coefficients 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 10C and the external temperature is 27C. Determine the heat loss through such wall 6m high and 10m long. (HW)

How many Watts will be radiated from a spherical black body 15cm in diameter at a temperature of 800C?

A liquid to liquid parallel flow heat exchanger is used to heat a cold fluid from 120℉ to 310℉. Assuming that the hot fluid enters at 500℉ and leaves at 400℉, calculate the (a) log mean temperature difference and (b) arithmetic mean temperature difference for the heat exchanger.

A Carnot refrigeration cycle absorbs heat at -12C and rejects it at 40C. Calculate the coefficient of performance of this refrigeration cycle.

A Carnot refrigeration cycle absorbs heat at -12C and rejects it at 40C. If the cycle is absorbing 15 kW at the -12C temperature, how much power is required?

A Carnot refrigeration cycle absorbs heat at -12C and rejects it at 40C. If a Carnot heat pump operates between the same temperatures as this refrigeration cycle, what is the performance factor?

A Carnot refrigeration cycle absorbs heat at -12C and rejects it at 40C. If a Carnot heat pump operates between the same temperatures as this refrigeration cycle, what is the rate of heat rejection at the 40C temperature if the heat pump absorbs 15 kW at the -12C temperature

A refrigeration system operates on the reversed Carnot cycle. The minimum and maximum temperatures are -13F and 162F, respectively. If the heat rejected at the condenser is 95 BTU/s, find the power input required in BTU/min.

If in a standard vapor-compression cycle using Refrigerant 22, the evaporating temperature is -5C and the condensing temperature is 30C, calculate the work of compression.

h1 = 403.2 kJ/kg

h2 = 429 kJ/kg

h3 = 236.6 kJ/kg = h4

If in a standard vapor-compression cycle using Refrigerant 22, the evaporating temperature is -5C and the condensing temperature is 30C, calculate the refrigerating effect.

h1 = 403.2 kJ/kg

h2 = 429 kJ/kg

h3 = 236.6 kJ/kg = h4

If in a standard vapor-compression cycle using Refrigerant 22, the evaporating temperature is -5C and the condensing temperature is 30C, calculate the heat rejected in the condenser.

h1 = 403.2 kJ/kg

h2 = 429 kJ/kg

h3 = 236.6 kJ/kg = h4

If in a standard vapor-compression cycle using Refrigerant 22, the evaporating temperature is -5C and the condensing temperature is 30C, calculate the coefficient of performance.

h1 = 403.2 kJ/kg

h2 = 429 kJ/kg

h3 = 236.6 kJ/kg = h4

Calculate the specific volume of an air-vapor mixture in cubic meters per kilogram of dry air when the following conditions prevail: t = 30°C , ω = 0.015kg/kg, and Pt = 90 kPa

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

In an air conditioning system, if the re-circulated air is three times the outside air and the mass of the supply air is 20 kg/s, what is the mass of the outside air?

An assembly hall was to have an air conditioning unit installed which would be maintained at 26°C dry bulb and at 50% RH. The unit delivers air at 15°C dry bulb temperature and the calculated sensible heat load is 150 kW and latent heat is 51.3 kW. Twenty percent by weight of extracted air is made up of outside air at 34°C dry bulb and 60% RH while 80% is extracted by the air conditioner from the assembly hall. Determine the air conditioners refrigeration capacity in tons of refrigeration.

@26°C DB; 50% RH, h2 = 53 kJ/kg

@34°C DB; 60% RH, h3 = 86.5 kJ/kg

One kilogram of a perfect gas (air) is used as a working substance in a Carnot power cycle. At the beginning of isentropic compression, the temperature is 326 K and the absolute pressure is 359 kPa. The absolute pressure at the end of the isentropic compression is 1373 kPa. For this cycle, the isothermal expansion ratio (V2/V1) is 2.0. Calculate the heat supplied.

One kilogram of a perfect gas (air) is used as a working substance in a Carnot power cycle. At the beginning of isentropic compression, the temperature is 326 K and the absolute pressure is 359 kPa. The absolute pressure at the end of the isentropic compression is 1373 kPa. For this cycle, the isothermal expansion ratio (V2/V1) is 2.0. Calculate the heat rejected.

One kilogram of a perfect gas (air) is used as a working substance in a Carnot power cycle. At the beginning of isentropic compression, the temperature is 326 K and the absolute pressure is 359 kPa. The absolute pressure at the end of the isentropic compression is 1373 kPa. For this cycle, the isothermal expansion ratio (V2/V1) is 2.0. Calculate the net work.

At the beginning of the compression an ideal Diesel cycle using an air has a pressure of 15 psia, a temperature of 75°F, and a specific volume of 13.2 ft3/lbm. For a compression ratio of 15 and heat addition of 352 BTU/lbm. Calculate the heat rejected.

At the beginning of the compression an ideal Diesel cycle using an air has a pressure of 15 psia, a temperature of 75°F, and a specific volume of 13.2 ft3/lbm. For a compression ratio of 15 and heat addition of 352 BTU/lbm. Calculate the work net.

At the beginning of the compression an ideal Diesel cycle using an air has a pressure of 15 psia, a temperature of 75°F, and a specific volume of 13.2 ft3/lbm. For a compression ratio of 15 and heat addition of 352 BTU/lbm. Calculate the thermal efficiency

At the beginning of the compression an ideal Diesel cycle using an air has a pressure of 15 psia, a temperature of 75°F, and a specific volume of 13.2 ft3/lbm. For a compression ratio of 15 and heat addition of 352 BTU/lbm. Calculate the horsepower developed at m = 0.5 lb/s.