HW7 spring 2011

HW7 spring 2011 - 3 In normal operation a paper mill...

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CHEG 2313 Thermo I HW#7 Spring 2011 Due Wednesday, March 30, 2011 in class. 1. A cyclical engine receives 550 kJ of heat from a reservoir at 800 K, delivers 225 kJ of work, and rejects 325 kJ of heat to a reservoir at 175 K. Does this engine violate the either the First Law or the Second Law? Compare the efficiency of this engine to that of a Carnot engine. (5 pts) 2. A house uses an air conditioner to maintain a house at a comfortable 68 ° F. The outside air on a hot Arkansas day is 97 ° F. The air conditioner requires 7.5 kW of power and operates at a coefficient of performance equal to 65% of the Carnot value. Determine the amount of heat that must be removed per hour. (5 pts)
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Unformatted text preview: 3. In normal operation, a paper mill generates excess steam at 20 bar and 400°C. It is planned to use this steam as the feed to a turbine to generate electricity for the mill. There are 5,000 kg/hr of steam available, and it is planned that the exit pressure of the steam will be 2 bar. a) Assuming the turbine is well insulated (no heat losses), what is the maximum power that can be generated by the turbine? (7 pts) b) A real turbine operating under similar conditions to part (a) has an efficiency of 80%. Determine the amoun of work performed by this turbine and the outlet temperature. (8 pts)...
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This note was uploaded on 04/01/2011 for the course CHEG 2313 taught by Professor Staff during the Spring '11 term at Arkansas.

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