The figure below shows a vapor power cycle that provides process heat and produces power. The steam generator produces vapor at 500 lbf/in.2, 800°F, at a rate of 8 x 104 lb/h. Eighty-eight percent of the steam expands through the turbine to 10 lbf/in.2 and the remainder is directed to the heat exchanger. Saturated liquid exits the heat exchanger at 500 lbf/in.2 and passes through a trap before entering the condenser at 10 lbf/in.2 Saturated liquid exits the condenser at 10 lbf/in.2 and is pumped to 500 lbf/in.2 before entering the steam generator. The turbine and pump have isentropic efficiencies of 85% and 89%, respectively. For the process heat exchanger, assume the temperature at which heat transfer occurs is 465°F. Let T0 = 60°F, p0 = 14.7 lbf/in.2 Determine: (a) the magnitude of the process heat production rate, in Btu/h. (b) the magnitude of the rate of exergy output, in Btu/h, as net work. (c) the rate of exergy transfer, in Btu/h, to the working fluid passing through the steam generator.
Heat Exchangers
Heat exchangers are the types of equipment that are primarily employed to transfer the thermal energy from one fluid to another, provided that one of the fluids should be at a higher thermal energy content than the other fluid.
Heat Exchanger
The heat exchanger is a combination of two words ''Heat'' and ''Exchanger''. It is a mechanical device that is used to exchange heat energy between two fluids.
The figure below shows a vapor power cycle that provides process heat and produces power. The steam generator produces vapor at 500 lbf/in.2, 800°F, at a rate of 8 x 104 lb/h. Eighty-eight percent of the steam expands through the turbine to 10 lbf/in.2 and the remainder is directed to the heat exchanger. Saturated liquid exits the heat exchanger at 500 lbf/in.2 and passes through a trap before entering the condenser at 10 lbf/in.2
Saturated liquid exits the condenser at 10 lbf/in.2 and is pumped to 500 lbf/in.2 before entering the steam generator. The turbine and pump have isentropic efficiencies of 85% and 89%, respectively. For the process heat exchanger, assume the temperature at which heat transfer occurs is 465°F. Let T0 = 60°F, p0 = 14.7 lbf/in.2
Determine:
(a) the magnitude of the process heat production rate, in Btu/h.
(b) the magnitude of the rate of exergy output, in Btu/h, as net work.
(c) the rate of exergy transfer, in Btu/h, to the working fluid passing through the steam generator.
(d) the magnitude of the rate of exergy output, in Btu/h, with the process heat.
(e) the magnitude of the rate of exergy loss, in Btu/h, from the working fluid passing through the condenser.
(f) the sum of the rate of exergy destrution, in Btu/h, in the turbine, process heat exchager, trap, and pump.
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