hw_2_Nuclear__Fosile - a ) Calculate the amount of heat...

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MMAE 426, MMAE 522 Nuclear, Fossil-Fuel, and Sustainable Energy Systems 1 Homework 2, due Wednesday, Sept. 22 Reading assignment: Lienhardt, Chapter 3, “Heat Exchanger Design” Problem 2.1 Calculate the heat exchanger area A[m 2 ] using the LMTD Method, assuming a) The counter flow. b) Cross flow The overall heat transfer coefficient U = 1000 W /m 2 K. The fluid is water on both sides, c p = 4.19 kJ /kg-K. The following information is given Hot side: m h = 1 kg/s T h,in =90 ° C, T h,out =60 ° C Cold side: m C = 2 kg/s T C,in =40 ° C T C,out = ? Problem 2.2 Consider again the problem 3 from HW1: Problem 3. In an ideal Rankine cycle with superheat and reheat, steam enters the first-stage turbine at 8.0 MPa, 480°C, and expands to 0.7 MPa. It is then reheated to 445°C before entering the second-stage turbine, where it expands to the condenser pressure of 0.008 MPa. The net power output is 1000 MW.
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Unformatted text preview: a ) Calculate the amount of heat that has to be transferred to the working fluid in order to: a1. bring the water to the boiling point. a2. evaporate the water and a3 superheat the steam before the high pressure and low pressure turbines. b ) The condenser (heat exchanger Fig.1) operates by transferring Q out to the nearby river. Assume that: - River temperature is 10 C before it enters the heat exchanger. - River temperature must not exceed 15 C Determine: b1. The flow rate of water (from the river) needed, kg/s. b2. The area needed for heat transfer. b3. The diameter, length and number of tubes (to be discussed in class, on Monday). Fig. 1 2.3 Complete the following table: Fuel Price Energy Density [kJ/kg] Energy Density [kJ/m3] $/kJ Coal ___per tone Oil $72 per barrel Gasoline $3 per gallon Electricity $0.05 per kWh Note: 1 barrel=0.1589 m3....
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This note was uploaded on 09/24/2010 for the course MMAE 592 taught by Professor Alexanderostrogorsky during the Spring '10 term at Illinois Tech.

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