Chapter 8, Problem 8.49P

A fraction of some power to a motor (1), 2 kW, is turned into heat transfer at 500 K (2) and then it dissipates in the ambient at 300 K (3). Give the rates of exergy along the process 1-2-3.

Given 0.603MW electrical power supplied to a boiler when the temperature of the entering water is 20 C and the exiting temperature is 89 C. The flow of.the pressured water is 2 Kg/s. There is a negligible pressure drop through this boiler and it operates at a constant pressure of 3 bars. The specific heat is c = 4,370 J/(Kg K).  a) Calculate the total rate of entropy production b) Calculate the total rate of exergy destruction (W). The dead state temperature is 293.2 K and pressure is 1 bar. c) Calculate the mass flowrate of fuel (natural gas, CH4) required to heat the water flow to the conditions of the problem if the electrical heating device is replaced with a gas fired boiler. The high heating value (HHV) of the fuel is 50.02 MJ/kg.

A- Air at 300 K and 1 bar is compressed adiabatically to 8 bar. It is then cooled at constant volume and further expanded isothermally so as to reach the initial condition. Find the net work and heat for this cycle.

78 kg of water vapor is found as saturated vapor at 650 kPa pressure in a cube-shaped container with a fixed volume. The cube lost heat and its pressure dropped to 325 kPa. Since the environmental conditions are 100 kPa 25 ºC, find the exergy change of the steam in the first and the last state, the exergy change in the steam, the exergy destruction and the second-law efficiency for this process change.

I was getting 35.4 but correct answer is 0.228. please help me to solve it

40°C 4. A mixing chamber receives 5 kg/min of ammonia as saturated liquid at -20°C from one line (1) and ammonia at 40°C, 250 kPa from another line (2). The chamber also receives 325 kJ/min of energy as heat transferred from a 40°C reservoir as shown in figure. At the outlet, ammonia leaves as saturated vapor at -20°C. Find the mass flow rate in second line and calculate the total entropy generation in the process. Is this process possible?

A feedwater heater has 5 kg/s water at 5 MPa and 40°C flowing through it, being heated from two sources, as shown in Fig. 8.6. One source adds 900 kW from a 100°C reservoir, and the other source transfers heat from a 200°Creservoir such that thewater exit condition is 5 MPa, 180°C. Find the reversible work and the irreversibility.   KINDLY HELP WITH THIS QUESTION ,ON HOW ONE GET VALUES FROM STEAM TABLE FOR INLET AND EXIT STATE? Please let me know which steam table did you use and also indicate table number and tible of the table used ,lastly show all calculations.

According to the Carnot cycle, the thermal efficiency of a working heat machine is 28%, and water vapor is used as the working fluid. Heat transfer to the working fluid occurs at 350°C, and at this time the fluid passes from a saturated liquid state to a saturated vapor state. Since 5 kg of fluid circulates per hour in the cycle, find the power of this heat machine using the entropy of evaporation.

Give me right solution.. Urgent please