Introduction to Refrigeration and Air Conditioning Systems: Theory and Applications

165 Pages·2022·2.156 MB·English

by  Allan T. Kirkpatrick

Synthesis Lectures on
Mechanical Engineering
Allan T. Kirkpatrick
Introduction to
Refrigeration and Air
Conditioning Systems
Theory and Applications
Second Edition
Synthesis Lectures on Mechanical
Engineering
Thisseriespublishesshortbooksinmechanicalengineering(ME),theengineeringbranch
that combines engineering, physics and mathematics principles with materials science to
design,analyze,manufacture,andmaintainmechanicalsystems.Itinvolvestheproduction
and usage of heat and mechanical power for the design, production and operation of
machines and tools. This series publishes within all areas of ME and follows the ASME
technical division categories.
Allan T. Kirkpatrick
Introduction
to Refrigeration and Air
Conditioning Systems
Theory and Applications
Second Edition
AllanT.Kirkpatrick
ColoradoStateUniversity
FortCollins,CO,USA
ISSN2573-3168 ISSN2573-3176 (electronic)
SynthesisLecturesonMechanicalEngineering
ISBN978-3-031-16775-1 ISBN978-3-031-16776-8 (eBook)
https://doi.org/10.1007/978-3-031-16776-8
1stedition:©SpringerNatureSwitzerlandAG2022
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Preface
Thesecondeditionbuildsonthefoundationestablishedbythepreviousfirsteditionpub-
lishedin2017.Thefirsteditioncoveredbackgroundinformation,description,andanalysis
offourmajorcoolingsystemtechnologies—vaporcompressioncooling,evaporativecool-
ing,absorptioncooling,andgascooling.Thesecondeditionhasbeenexpandedtoinclude
increased coverage of cooling system refrigerants, fluid mechanics, heat transfer, and
building cooling loads. With increasing climate change due to the buildup of greenhouse
gas emissions in the atmosphere, there has been a worldwide impetus to transition to
cooling systems and refrigerants that have a low or even zero global warming poten-
tial.AshortreviewofrefrigerationandairconditioningisgiveninChapterOne.Chapter
Twodiscussestheanalysisandperformanceofvaporcompressionsystems,whileChapter
Three covers evaporative, absorption, and gas cooling systems. Chapter Four reviews the
relevant fluid mechanics, and Chapter Five reviews the heat transfer fundamentals. The
determination of building cooling loads is the subject of Chapter Six. Finally, Chapter
Seven provides detailed information and analysis of the components—heat exchangers,
pumps, and compressors, used to assemble a cooling system.
The text is written as a tutorial for engineering students and practicing engineers who
want to become more familiar with the performance of refrigeration and air conditioning
systems. The goals are to familiarize the reader with cooling technology nomenclature,
and provide insight into how refrigeration and air conditioning systems can be mod-
eled and analyzed. Emphasis is placed on constructing idealized thermodynamic cycles
to represent actual physical situations in cooling systems. The book contains numerous
practical examples to show how one can calculate the performance of cooling system
components. By becoming familiar with the analyses presented in the examples, one can
gainafeelfortherepresentativevaluesofthevariousthermalandmechanicalparameters
that characterize cooling systems.
Fort Collins, CO, USA Allan T. Kirkpatrick
August 2022
v
Acknowledgements
Discussions with Colorado State Professors Daniel Wise and Bret Windom about refrig-
eration and air conditioning issues have been very helpful. Former CSU graduate
studentsCharlesBoardman,MichaelDeru,KevinKnappmiller,andJoelNeymarkworked
tirelessly with me on building energy use research problems.
ManythankstotheeditorialstaffatSpringerNaturefortheirassistancewiththesecond
edition.Mr.PaulPetraliadeservesspecialacknowledgmentforhisencouragementofthis
project.IwouldliketothankmywifeSusanandmyextendedfamily,Anne,Matt,Maeve,
Michael, Rob, Kristin, Thomson, Charlotte, and Theo for their unflagging support while
the second edition was being written.
Finally,thiseditionisdedicatedtomylatefather,EdwardT.Kirkpatrick,whosparked
my interest in mechanical engineering years ago.
vii
Contents
1 IntroductiontoCoolingTechnologies ................................... 1
1.1 Introduction .................................................... 1
1.1.1 Cooling Technologies ..................................... 2
1.2 Brief History of Cooling Technologies ............................. 3
1.2.1 Refrigeration ............................................. 3
1.2.2 Air Conditioning ......................................... 4
1.3 Thermodynamic Background ..................................... 6
1.3.1 Thermodynamic Properties ................................. 6
1.3.2 Energy Equation, Heat, and Work ........................... 7
1.4 Psychrometrics ................................................. 9
1.4.1 Properties of Air–Water Vapor Mixtures ..................... 9
1.4.2 Adiabatic Saturation and Wet Bulb Temperatures ............. 11
1.4.3 Psychrometric Chart ...................................... 14
1.5 Thermal Comfort ............................................... 18
1.6 Further Reading ................................................. 22
References ........................................................... 22
2 VaporCompressionCoolingCycles .................................... 23
2.1 Introduction .................................................... 23
2.2 Carnot Refrigeration Cycle ....................................... 23
2.3 Vapor Compression Cycle Operation .............................. 25
2.4 Vapor Compression Cycle Analysis ................................ 25
2.5 Efficiency Measures—COP, EER, and SEER ....................... 28
2.6 Refrigerants .................................................... 30
2.7 Effect of Evaporator and Condenser Temperature .................... 36
2.8 Part Load Performance .......................................... 40
2.9 Multistage Vapor Compression Systems ............................ 41
2.10 Further Reading ................................................. 47
References ........................................................... 47
ix
x Contents
3 Evaporative,Absorption,andGasCoolingCycles ....................... 49
3.1 Introduction .................................................... 49
3.2 Evaporative Cooling ............................................. 49
3.2.1 Direct Evaporative Cooling ................................ 50
3.2.2 Indirect Evaporative Cooling ............................... 51
3.3 Absorption Refrigeration Cycles .................................. 55
3.3.1 Absorption Cycle Operation ................................ 57
3.3.2 Absorption Cycle Analysis ................................. 58
3.4 Gas Refrigeration Cycle ......................................... 61
3.4.1 Thermodynamic Analysis .................................. 62
3.5 Further Reading ................................................. 64
References ........................................................... 64
4 FluidFlowinRefrigerationandAirConditioningSystems ............... 65
4.1 Introduction .................................................... 65
4.2 Fluid Properties ................................................. 65
4.3 Fluid Flow Measurement ......................................... 68
4.4 Continuity Equation ............................................. 69
4.5 Bernoulli’s Equation ............................................. 71
4.6 Energy Losses in Fluid Flow ..................................... 73
4.7 Pump Work and Power .......................................... 76
4.8 Air Flow in HVAC Systems ...................................... 76
4.9 HVAC Duct Networks ........................................... 78
4.10 Fan Performance ................................................ 80
4.11 Cooling Coil Fluid Flow ......................................... 83
4.12 Room Air Flow ................................................. 84
4.13 Mixing Boxes .................................................. 88
4.14 Further Reading ................................................. 89
References ........................................................... 89
5 HeatTransferinHVACSystems ....................................... 91
5.1 Introduction .................................................... 91
5.2 Conduction Heat Transfer ........................................ 91
5.3 Convection Heat Transfer ........................................ 92
5.4 Thermal Resistance .............................................. 95
5.5 Heat Transfer in Ductwork ....................................... 98
5.5.1 Duct Heat Transfer ....................................... 98
5.5.2 Fan Heat Gain ............................................ 101
5.6 Radiation Heat Transfer .......................................... 102
5.7 Radiation Properties ............................................. 103
5.8 Radiation Exchange Between Surfaces ............................. 104
5.9 Multi-mode Heat Transfer ........................................ 106
Contents xi
5.10 Further Reading ................................................. 108
References ........................................................... 108
6 CoolingLoadsinBuildings ............................................ 109
6.1 Introduction .................................................... 109
6.2 Sensible and Latent Building Loads ............................... 110
6.3 Internal Loads .................................................. 112
6.4 Weather Data ................................................... 113
6.5 Ventilation ..................................................... 115
6.6 Infiltration ...................................................... 117
6.7 Solar Radiation ................................................. 123
6.8 Wall Conduction ................................................ 127
6.9 Further Reading ................................................. 128
References ........................................................... 128
7 CoolingEquipment ................................................... 129
7.1 Introduction .................................................... 129
7.2 Heat Exchangers ................................................ 129
7.3 Heat Transfer in Heat Exchangers ................................. 132
7.4 Condensers ..................................................... 134
7.4.1 Condensation Heat Transfer ................................ 136
7.4.2 Evaporative Condensers ................................... 138
7.5 Evaporators .................................................... 138
7.6 Boiling Heat Transfer ............................................ 140
7.7 Cooling Towers ................................................. 141
7.8 Compressors ................................................... 142
7.8.1 Reciprocating Compressors ................................ 142
7.8.2 Centrifugal Compressors ................................... 145
7.8.3 Compressor Lubrication ................................... 151
7.9 Expansion Valves ............................................... 151
7.10 Further Reading ................................................. 153
References ........................................................... 153
AppendixA:PhysicalConstantsandConversionFactors .................... 155