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Optimization of Vapor Compression Cycles

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2014 ASEE Annual Conference & Exposition


Indianapolis, Indiana

Publication Date

June 15, 2014

Start Date

June 15, 2014

End Date

June 18, 2014



Conference Session

Thermodynamics, Fluids, and Heat Transfer I

Tagged Division

Mechanical Engineering

Page Count


Page Numbers

24.958.1 - 24.958.23



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Paper Authors


David C. Zietlow Bradley University

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Professor of Mechanical Engineering

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This paper will revolutionize the way you think about teaching thermodynamics. Thescope of this work is to focus on cooling systems and, in particular, the most common coolingsystems based on the vapor compression cycle. The traditional methods of teachingthermodynamics do not equip students with the tools they need to optimize the vaporcompression cycle. This work will provide you and your students with the tools they need todesign and optimize the vapor compression cycle within the first semester. “Design” like the word “love” is overused to the point where it has lost its meaning.When design is used in the context of cooling systems typically what is understood is that thesize of the cooling system is to be determined. Sizing the system is an important first step. Butdesign is more, much more, than sizing. When you design a cooling system, you want the bestcooling system for the application. This leads you to another overused and misapplied word;“optimization”. In any optimization process, one needs to determine the objective function.This is a function that has a minimum or maximum. Traditional thermodynamics equips the student with the ability to determine thecoefficient of performance (COP) and irreversibilities of each process of the cycle. They may betempted to maximize the COP or minimize the irreversibilities when optimizing the system.This paper will help you understand that these objective functions do not yield a realisticoptimum. The only viable objective function for the optimization of cooling systems is the total lifecycle costs (TC). The goal is to minimize the total costs as a function of the design variableswhich in this case are the effectiveness of the evaporator and condenser and the isentropicefficiency of the compressor. This paper will show you how to integrate a couple simple toolsinto your first semester course on thermodynamics which will enable students to truly optimizevapor compression cycles.

Zietlow, D. C. (2014, June), Optimization of Vapor Compression Cycles Paper presented at 2014 ASEE Annual Conference & Exposition, Indianapolis, Indiana. 10.18260/1-2--22891

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