Chapter 4, Problem 4.52P

A natural gas-fired steam power plant consumes 360 kg/min of natural gas. If the heat losses to the surrounding air from the steam as it passes through pipes and other components are estimated to be about 100 GJ/h . The heating value of the natural gas is 45,000 kJ/kg. Part 1:1) Determine the rate of the heat supplied by the fuel to the steam plant.2) Determine the rate of waste heat rejection by the seam plant.3) Determine the net power delivered by the steam power plant to the generator.4) Calculate the efficiency of the steam power plant.   Part two :If the steam power plant is connected to a generator that is with 95% efficiency.1) Determine the output energy of the generator.2) Calculate the total efficiency of the combined turbine and generator system.3) Critically compare how changes in the thermal efficiency of a heat transfer process can affect its performance

Gases after combustion are discharged from a flue in a facility to the atmosphere at a temperature of 250 °C and a flow rate of 25000 m3/h. It is desired to benefit from the heat of this waste gas in heating. There is a site with 40 residences, each with a heating load of approximately 8 kW, located 3 km from the facility.1- Determine the substation capacity to be used, taking into account the hot water requirement for each house on the site.2- Determine the substation inlet/outlet temperature and the heat exchanger water inlet/outlet temperatures. The temperature of the water leaving the heat exchanger is required not to exceed 95 ° C. The pipeline between the facility and the site is underground pipeline. Determine the required data by considering the region where the facility is located, calculate the heat losses in the line and find the required insulation thickness.3- Calculate the total capacity including losses and determine the required exchanger dimensions. insulation…

Gases after combustion are discharged from a flue in a facility to the atmosphere at a temperature of 250 °C and a flow rate of 25000 m3/h. It is desired to benefit from the heat of this waste gas in heating. There is a site with 40 residences, each with a heating load of approximately 8 kW, located 3 km from the facility.1- Determine the substation capacity to be used, taking into account the hot water requirement for each house on the site.2- Determine the substation inlet/outlet temperature and the heat exchanger water inlet/outlet temperatures. The temperature of the water leaving the heat exchanger is required not to exceed 95 ° C. The pipeline between the facility and the site is underground pipeline. Determine the required data by considering the region where the facility is located, calculate the heat losses in the line and find the required insulation thickness.3- Calculate the total capacity including losses and determine the required exchanger dimensions.

The 5-mm-thick bottom of a 200-mm-diameter pan may be made from aluminum (k= 240 W/m·K) or copper (k= 390 W/m·K). When used to boil water, the surface of the bottom exposed to the water is nominally at 110°C and heat is transferred from the stove to the pan at a rate of 1200 W. What is the temperature of the surface in contact with the stove for each of the two materials?Aluminum:T= _____ °CCopper:T= _____ °C

Steam is used to heat a cylindrical open tank of water until it boils, after which a proportion of the water in the tank is vaporised. The tank has an internal diameter of 1 m and is initially filled with water to a depth of 2 m. At the start of the process, this water is at 19°C and has a density of 998 kg/m3 . It may be assumed that ambient atmospheric pressure is 1 bar and that any effects arising from hydrostatic head can be ignored, as can heat losses from the tank to the surrounding environment. The heating medium is saturated steam at 5 bar, which enters a heating coil at the base of the tank at 5 kg/min, loses heat to the water in the tank and condenses to form saturated liquid condensate at this pressure. Using the steam table supplied: a) Find the temperature (°C) and power rating (kW) of the heater coil.  b) Find the boiling point of the water in the tank under these conditions, and the time required to bring the water to this temperature.  c) Find the proportion of water…

Consider a 1 cm thick copper wall (k=375 W/m K) whose one surface is exposed to condensing water vapor (h=10000 W/m² K) at a temperature of 200°C . The other surface is in contact with ambient air (h= 5 W/m²K) at a temperature of 25°C. a) Calculate the heat per unit area across the plate. b) Determine the temperatures at both surfaces of the wall.

a. What is the heat flux, q"1 [in W/m2], at the left-hand side of layer B? Express your answer as a negative number if the heat flux goes to the left, and as a positive number if the heat flux goes to the right. b.What is the heat flux, q"2 ( in W/m2) at the right-hand side of layer B? Express your answer as a negative number if the heat flux goes to the left, and as a positive number if the heat flux goes to the right. c. What is the temperature, T1, on the left-hand side of layer B, in Celsius? d. What is the temperature, T2, on the right-hand side of layer B, in Celsius?

The average thermal conductivity of the walls (including windows) and roof of a house in the figure shown below is 4.8  10-4 kW/m · °C, and their average thickness is 21.6 cm. The house is heated with natural gas, with a heat of combustion (energy given off per cubic meter of gas burned) of 9,300 kcal/m3. How many cubic meters of gas must be burned each day to maintain an inside temperature of 27.4°C if the outside temperature is 0.0°C? Disregard surface air layers, radiation, and energy loss by heat through the ground. m3

How much natural gas do you need to burn to heat twenty liters of water from 0 degrees C to 30 degrees C? and  Calculate the amount of thermal energy required to raise the temperature of 80 liters of water from 20° C to 40° C. same formula?? and how do you do it?