Steam in the condenser of a power plant is to be condensed at a temperature of 30°C with cooling water from a nearby lake, which enters the tubes of the condenser at 14°C and leaves at 22°C. The surface area of the tubes is 45 m2, and the overall heat transfer coefficient is 2100 W/m2K. Determine the mass flow rate of the cooling water needed and the rate of condensation of the steam in the condenser.

The ducts of an air heating system pass through an unheated area. As a result of heat losses, the temperature of the air in the duct drops by 4°C. If the mass flow rate of air is 120 kg/min, determine the rate of heat loss from the air to the cold environment

Steam enters a turbine with a velocity of 16 m/s and specific enthalpy 2990kJ/kg. The steam leaves the turbine with a velocity of 37 m/s and specific enthalpy 2530kJ/kg. The heat lost to the surroundings as the steam passes through the turbine in 25 kJ/kg. The steam flow rate is 324000 kg/h. Determine the work output from the turbine in kilowatts

The components of an electronic system dissipating 180 W are located in a 1-m-long horizontal duct whose cross section is 16 cm * 16 cm. The components in the duct are cooled by forced air, which enters at 27°C at a rate of 0.65 m3/min. Assuming 85 percent of the heat generated inside is transferred to air flowing through the duct and the remaining 15 percent is lost through the outer surfaces of the duct, determine (a) the exit temperature of air and (b) the highest component surface temperature in the duct. As a first approximation assume flow is fully developed in the channel. Evaluate properties of air at a bulk mean temperature of 35°C. Is this a good assumption?

Stainless steel ball bearings (p = 8085 kg/m³ and cp = 0.480 kJ/(kg °C)) having a diameter of 1.5 cm are to be quenched in water at a rate of 900 per minute. The balls leave the oven at a uniform temperature of 1000°C and are exposed to air at 25 °C for a while before they are dropped into the water. If the temperature of the balls drops to 900°C prior to quenching, determine the rate of heat transfer from the balls to the air.

Water is stored in a large, well-insulated storage tank at 21.0°C open to atmosphere. It is pumped at a rate of 40 m3/h to another tank 25 m above, which is also open to atmosphere. The motor driving the pump supplies energy at the rate of 9.5 kW. The water passes through a heat exchanger where 255 kW of heat is added to the water. The total friction loss (ΣF) in the system is 90.25 J/kg. Determine the final temperature of the water at the second tank

Why is it important to clean the condenser coils of a household refrigerator a few times a year? Also, why is it important not to block airflow through the condenser coils?

A fruit juice is being heated in an indirect heat exchanger using steam as a heating medium. The product fl ows through the heat exchanger at a rate of 1500 kg/h and the inlet temperature is 20C. Determine the quantity of steam required to heat the product to 100C when only latent heat of vaporization (2200 kJ/kg) is used for heating. The specifi c heat of the product is 4 kJ/(kg C).

ce an answer is submit you will be unable to return to this part. A refrigeration system is to cool bread loaves with an average mass of 390 g from 30°C to -10°C at a rate of 1200 loaves per hour with refrigerated air at -30°C. Take the average specific and latent heats of bread to be 2.93 kJ/kg-°C and 109.3 kJ/kg. Determine the size of the compressor of the refrigeration system, in kW, for a COP of 1.2 for the refrigeration system. 4 The size of the compressor of the refrigeration system is kW.

Engine oil (C, =2100 J/kg · °C) is to be heated from 20°C to 60°C at a rate of 0.3 kg/s in a 2-cm-diameter thin walled copper tube by condensing steam outside at a temperature of 130°C (hɛ =2174 kJ/kg). For an overall heat transfer coefficient of 650 W/m2 · °C, determine the rate of heat transfer and the length of the tube required to achieve it.