ENSC 2213 Thermodynamics Exam 3: Problems on Power Cycles and Entropy Change - Prof. Afshi, Exams of Thermodynamics

Download ENSC 2213 Thermodynamics Exam 3: Problems on Power Cycles and Entropy Change - Prof. Afshi and more Exams Thermodynamics in PDF only on Docsity! ENSC 2213 Thermodynamics EXAM 3 / 4- 10-09 NAME (20) Prohlem I. A reversible power cycle operates between a reservoir at temperature THand a lower-temperature reservoir at 7°C. At steady state, the cycle develops 40 kW of power while rejecting 1000 kJ/min of energy by heat transfer to the cold reservoir- For this cycle determine: (a) TH (in 0c) and (b) the thermal efficiency. .' t .) / 1..~() . - ,\ 0 I ) (f;- '" : / ;' '/ ) " ,. (.<')1..';]( I \ " .\, ~ '--r If" \ f \ -.- .. J I ~ \;' 1 K..... , . t: ---- ) \ lo'~ . I .\ (':0 c •. c:/ )\, _ .._- } r't,l \ ..., / !,'" ,'"' / 'I ! ~ \ _ Z'/.6!< .\:1 I / 1-, Ie. T.,r-; /( / , ENSC 2213 Thermodynamics EXAM 3 / 4-10-09 NAME (30) Problem 2. A Carnot power cycle receives heat at 477°C and rejects the waste heat to the environment at 27°(, The entire work output of the power cycle is used to drive a Carnot refrigerator that removes heat from the cooled space at -15"C at a rate of 400 kJ/min and rejects it to the same environment at 2TC. Determine: (a) the power input to the rcfrigerator (in kJ/min) (b) the rate of heat supplied to the power cycle (in kJ/min) and (c) the total rate of heat rejection by both cycles to the environment (in kJ/min). ,~.' ~ l(nOe i_ II-t • " ( - ..,- "l.f.- I ....., ,..- '7 \ _ ,<: - .••.•_., \ 1. {..•.(.-1-,. -..... ) ) 75'S'\( "cD I • .-." ( ~~S ( 1-1-," . - I, ; T ~" ~ \\ 'JJ //IWI. 0 )..------ ---~-~--~ (J'l " (~ I, ); 1_ ) uo <.' ---'(01'( f J - /, I l,'('.l 'r r /(~- /'Y~'., -c: ,( ')j, I:) '" .- .----- () 'rJ • \r',- Qr\ I