Exergy flow associated with a fluid stream when the fluid properties are variable can be determined by.

Air enters a compressor operating at steady state at 1.05 bar, 300 K, with a volumetric flow rate of 39 m³/min and exits at 12 bar, 400 K. Heat transfer occurs at a rate of 6.5 kW from the compressor to its surroundings. Assuming the ideal gas model for air and neglecting kinetic and potential energy effects, determine the power input, in kW. Wcv = eTextbook and Media Save for Later kW Attempts: 0 of 5 used Submit Answer

Apply exergy balance to closed systems and control volumes.

Is energy added to the gas by heating or removed by cooling in each cycle? Support your claim in a coherent paragraph-length response that qualitatively compares the amounts of energy added to the gas by heating or removed by cooling in the two cycles and refers to the work done on the gas and the change in internal energy of the gas.

If heating from saturated liquid to saturated vapor would occur at 100°C (373.15 K), evaluate the exergy transfers accompanying heat transfer and work, each in kJ/kg. Ans. 484, 0.

Figure shows data for a portion of the ducting in ventilation system operating at steady state. The ducts are well insulated and the pressure is very nearly 1 bar throughout. Assuming the ideal gas model for air with Cp  = 1 kJ/kg · K. and ignoring kinetic and potential energy effects, determine: (a) the temperature of the air at the exit, in °C. (b) the exit diameter, in m. (c) the rate of entropy production within the duct, in kJ/min.

7.66 Referring to the discussion of Sec. Z.6.2 as required, evaluate the exergetic efficiency for each of the following cases, assuming steady-state operation with negligible effects of heat transfer with the surroundings: a. Turbine: Wer 1200 hp, e 250 Btu//lb, eg = 15 Btu/lb, m 240 lb/min. b. Compressor: Wev/m=-105 kJ /kg, e = 5 kJ/kg, eg = 90 kJ/kg, m 2 kg /s. c. Counterflow heat exchanger: mh = 3 kg/s, me 10 kg /s, ef = 2100 kJ/kg, e = 300 kJ/kg, É = 3.4 MW 10 lb /s, m3 15 b /s, en = 1000 Btu/Ib, eg = 50 Btu/Ib, eg = 400 Btu/lb d. Direct contact heat exchanger: m1

Expert Q&A A counterflow heat exchanger operates at steady state while being well-insulated from the surroundings with air and ammonia flowing in separate streams. Ammonia enters at state 1 with -20°C and a quality of 20% and exits at state 2 as saturated vapor at -20°C. Air enters at state 3 with pressure 1 bar and temperature 295 K and exits at state 4 with pressure 1 bar and temperature 265 K. The flow rate of air is 10 kg/s. Ignore kinetic and potential energy effects, and take the dead state as 1 bar and 300 K. a. Sketch states 1 and 2 on a T-s diagram, including the liquid-vapor dome. b. Describe the heat transfer inside the heat exchanger (what is transferring heat to what?) c. Determine the specific enthalpy of each state, in kJ/kg. d. Determine the mass flow rate of ammonia, in kg/s. e. Determine the rate of exergy destruction within the heat exchanger, in kW. f. Devise and evaluate an exergetic efficiency for the heat exchanger. Done