Advances in Air Conditioning Technologies : Improving Energy Efficiency

313 Pages·2021·14.379 MB·English

by  Chua Kian Jon, Md Raisul Islam, Ng Kim Choon, Muhammad Wakil Shahzad

Green Energy and Technology
Chua Kian Jon
Md Raisul Islam
Ng Kim Choon
Muhammad Wakil Shahzad
Advances
in Air
Conditioning
Technologies
Improving Energy Efficiency
Green Energy and Technology
Climate change, environmental impact and the limited natural resources urge
scientific research and novel technical solutions. The monograph series Green
Energy and Technology serves as a publishing platform for scientific and
technological approaches to “green”—i.e. environmentally friendly and sustain-
able—technologies. While a focus lies on energy and power supply, it also covers
“green” solutions in industrial engineering and engineering design. Green Energy
and Technology addresses researchers, advanced students, technical consultants as
well as decision makers in industries and politics. Hence, the level of presentation
spans from instructional to highly technical.
**Indexed in Scopus**.
More information about this series at http://www.springer.com/series/8059
Chua Kian Jon Md Raisul Islam
(cid:129) (cid:129)
Ng Kim Choon Muhammad Wakil Shahzad
(cid:129)
Advances in Air
Conditioning Technologies
fi
Improving Energy Ef ciency
123
ChuaKian Jon Md Raisul Islam
Department ofMechanical Engineering Department ofMechanical Engineering
National University ofSingapore National University ofSingapore
Singapore, Singapore Singapore, Singapore
NgKim Choon Muhammad Wakil Shahzad
Environmental Science andEngineering Environmental Science andEngineering
KingAbdullah University of Science KingAbdullah University of Science
andTechnology andTechnology
Jeddah, SaudiArabia Jeddah, SaudiArabia
ISSN 1865-3529 ISSN 1865-3537 (electronic)
Green Energy andTechnology
ISBN978-981-15-8476-3 ISBN978-981-15-8477-0 (eBook)
https://doi.org/10.1007/978-981-15-8477-0
©SpringerNatureSingaporePteLtd.2021
Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpart
of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations,
recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission
orinformationstorageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilar
methodologynowknownorhereafterdeveloped.
The use of general descriptive names, registered names, trademarks, service marks, etc. in this
publicationdoesnotimply,evenintheabsenceofaspecificstatement,thatsuchnamesareexemptfrom
therelevantprotectivelawsandregulationsandthereforefreeforgeneraluse.
The publisher, the authors and the editors are safe to assume that the advice and information in this
book are believed to be true and accurate at the date of publication. Neither the publisher nor the
authors or the editors give a warranty, expressed or implied, with respect to the material contained
hereinorforanyerrorsoromissionsthatmayhavebeenmade.Thepublisherremainsneutralwithregard
tojurisdictionalclaimsinpublishedmapsandinstitutionalaffiliations.
ThisSpringerimprintispublishedbytheregisteredcompanySpringerNatureSingaporePteLtd.
The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721,
Singapore
Preface
Manycosmopolitancities,particularly thoseinthetropics,aretrappedinavicious
circlecausedbyurbanization,exacerbatedbyclimatechange,andlockedinbytheir
obsession with keeping their indoor cool and comfortable. Cities are getting hotter
due to global warming. As they get hotter, their air-conditioning needs burgeon.
Ironically,themoreair-conditioningisusedtocoolthebuildings’interior,themore
heat is dissipated to the environment; forming undesirable heat zones.
FirstinventedbyWillisCarrierin1902,vapourcompressionair-conditioningis
themostwidelyusedair-conditioningtechnologytoday.While,thistechnologyhas
served uswellfor more than acentury,it has alsopresented twokey challenges—
first, it is very energy-intensive and second, it is environmentally harmful. For
instance,intheUSA,about90%ofhomeshaveoneair-conditioningunitormore,
and they account for close to 6% of the nation’s total residential energy use. That
alone contributes close to 100 million tons of carbon dioxide into the atmosphere
every year [1]. In India, the International Energy Agency estimates that the peak
electricityloadfromairconditioningcouldclimbby10%by2050ifthetechnology
does not modernize [2]. Further, these mechanical air conditioners employ
hydrofluorocarbons(HFCs),atypeofindustrialchemical,astheircoolingagentsto
remove heat from their surroundings. Typically, these chemicals are not known to
beharmfulunlesstheyleakfromtheairconditionerstotheenvironment;butleaks
are common. When these HFCs are released into the atmosphere, they are capable
oftrappingmanytimesmoreheatintheatmospherethancarbondioxide;markedly
contributing to global warming.
To address these challenges, installing more efficient cooling systems is prob-
ably the best place to start. The more efficient the cooling system, the lesser the
energy used coupled with reduced heat dissipated to the environment; easing the
urban heat island effect and lowering cities’ contribution to climate change.
Presently,basedontheplethoraofresearchactivitiesconductedoverthelastfew
years,thereisnoshortageofinnovativeideastomakeairconditioninggreenerand
better.Someoftheseideasstrivetoenablecurrentunitstooperatemoreefficiently,
some attempt to combine old and new technologies, while others attempt to
engineernewair-conditioningprocessesentirely.Oneconcepttoyswiththeideaof
v
vi Preface
ditching the chemical coolants and using water as the only coolant to yield almost
freecooling.Anotheridea usesmembranetoeffectively removemoisture fromthe
air. The problems with large-scale employment of any of these ideas are cost,
economic of scale production, and wide-scale technological deployment. It is
noteworthythatcurrentvapourcompressionunitshavehadmorethan100yearsto
become exceptionally cheap. Nevertheless, the future of air conditioning is really
notinthetraditionalcompressiontechnologiesasweknowthemtodayifweareto
mitigate issues related to energy consumption and environmental well-being.
This book highlights the key recent developments in air-conditioning tech-
nologies for cooling and dehumidification with the specific objectives to improve
energyefficiencyandtominimizeenvironmentalimpacts.Keytechnologiesrelated
to cooling include heat-driven absorption and adsorption cooling and water-based
dew-point evaporative cooling. Technologies concerned with dehumidification
involve new generations of adsorbent-desiccant dehumidifiers, liquid-based desic-
cants,andmembranesthatcapableofsievingoutwatervapourfromtheair.Losses
incoolingcyclesandthermo-economicanalysisforasustainableeconomyarealso
presented. Since each of the individual area constitutes a broad and independent
branch of thermal science, an in-depth coverage of basic heat and mass transfer
principlesisavoided.Insteadreferencesareprovidedforreaderstoconsultstandard
textbooks or other relevant sources for detail derivations. The materials have been
judiciously selected to convey to readers interesting perspectives on recent tech-
nological developments pertaining to cooling and dehumidification. Each chapter
further endeavours to provide the readers with the tools necessary to perform
similarstudiesforotherthermalsystemsorprocessesinvolvingthetransferofheat
and mass during different stages of cooling and dehumidification, i.e. air condi-
tioning. Some fundamental works on modelling of the dew-point evaporative
cooling transfer processes are presented to illustrate to readers the direct link
between fundamentalthermal scienceandpractical applications.Having witnessed
the transitory process from basic thermal engineering to air conditioning applica-
tions demonstrated in this book, the reader can help to promote better interaction
anddialoguebetweenresearchersandengineeringpractitioners.Itisworthytonote
that,althoughthisbookhasbeendividedintochapterswithcertainairconditioning
themes, the presentation in each chapter does not necessarily fit into neat pigeon-
holes; there are times when an overlapping of information exits.
The introductory chapter presents an overview of the present state of cooling,
comparative energy consumption and sustainability of different existing and new
cooling technologies. Several recently actively pursued research topics on air
conditioningareintroducedinChap.2toprovidereaderswithaholisticperspective
onthepotentialofnewairconditioningtechnologiesandprocessesthatarecapable
ofreplacingvapourcompressioncoolingsystems.Chapter3providesanextensive
coverage on dew-point evaporative coolers. This chapter covers the fundamental
development of several counter-flow dew-point evaporative cooling processes
including several computational models during the transient and steady-state
coolingphases.It also includesseveralkey applicationsofthis unique evaporative
cooler under several industrial settings. Chapters 4–6, respectively, present recent
Preface vii
developments on air dehumidification, namely, desiccant-coated, liquid desiccant,
and membrane-based dehumidification. In desiccant-coated dehumidification, sev-
eral polymeric desiccants that can be coated on metallic heat exchangers are por-
trayed. In the chapter on liquid desiccant, the focus is on how novel moisture
removalcyclescanbedevelopedtopromoteenergy-efficientdehumidification.The
fundamental principle of membrane dehumidification, the importance of material
selection, and the rubric to assess membrane dehumidification process are also
included.Chapter7describesdissipativelossesindifferentcoolingcyclesandhow
these losses can be quantified and minimised. The focus of Chap. 8 is on the
efficacy comparison for cooling cycles and how efficiently these cycles convert
energytoproducecoolingeffects.Thelastchapter,Chap.9,willbeofgreatinterest
to technology investors and entrepreneurs. It focuses on the thermo-economic
analysis for cooling needs particularly life-cycle costing of different cooling tech-
nologies; benchmarking their economic potential with the conventional vapour
compression air conditioner.
Due to the broadness of recent scientific developments on air conditioning, the
selectionofthematerials andtheirbalancehasbeenamostdifficulttask.Pertinent
materials have been selected from literature and our published works. These are
judiciouslyputtogetherinaneasilydigestibleformat.Creditsshouldbelongtothe
original sources.Finally,we wouldlike toadd that thetechnical contentpresented
in this book has all been done in the spirit of contributing to the knowledge pool
of the existing resources on air conditioning—a subject that is mature yet still has
significant room to study and is certainly worthy to pursue.
In the spirit of expressing gratitude, the authors like to extend their heartfelt
thanks and appreciation tosome team members who haveassisted and contributed
to the documentation of some of the technical content presented in the various
chapters.Someofthesepeopleincluderesearchstaffandex-PhDstudents,namely,
Cui Xin, Lin Jie, Vivekh Prabakaran, Bui Duc Thuan, M Kum Ja, Oh Seung Jin,
Chen Qian, Muhammad Burhan, and other graduate students who have worked in
our laboratories.
Singapore, Singapore Chua Kian Jon
Singapore, Singapore Md Raisul Islam
Jeddah, Saudi Arabia Ng Kim Choon
Jeddah, Saudi Arabia Muhammad Wakil Shahzad
References
1. How Bad Is Your Air-Conditioner for the Planet? https://www.nytimes.com/2016/08/10/
science/air-conditioner-global-warming.html
2. India is the epicenter of rethinking air conditioning: https://qz.com/1675017/the-next-big-
disruption-in-air-conditioning-will-be-tested-in-india/
Contents
1 Present State of Cooling, Energy Consumption
and Sustainability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Building Comfortable Zone. . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 Air-Conditioning Market. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.4 Energy Consumed by the Air-Conditioning Systems. . . . . . . . . . 5
1.5 Cooling Degree Days (CDDs). . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.6 CO and GHG Emission from Air-Conditioning Systems . . . . . . 8
2
1.7 Future Roadmap. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.8 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2 Future of Air Conditioning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.2 Absorption/Adsorption Chillers . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.3 Dew-Point Evaporative Cooling Systems . . . . . . . . . . . . . . . . . . 26
2.4 Solid-Based Desiccant Dehumidification . . . . . . . . . . . . . . . . . . 31
2.5 Liquid-Based Desiccant Dehumidification . . . . . . . . . . . . . . . . . 36
2.5.1 Adiabatic Liquid-Desiccant Dehumidification Systems . . . 38
2.5.2 Internally Cooled Liquid-Desiccant Dehumidification
Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
2.6 Membrane-Based Air Dehumidification . . . . . . . . . . . . . . . . . . . 41
2.6.1 Membrane Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
2.7 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
3 Dew-Point Evaporative Cooling Systems. . . . . . . . . . . . . . . . . . . . . . 53
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
3.2 Principle and Features of the Dew-Point Evaporative Cooling. . . 58
3.3 Types of Dew-Point Evaporative Coolers. . . . . . . . . . . . . . . . . . 60
ix
x Contents
3.4 Analytical Models. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
3.4.1 Cross-Flow Dew-Point Evaporative Cooler . . . . . . . . . . . 73
3.4.2 Counter-Flow Dew-Point Evaporative Cooler . . . . . . . . . 84
3.4.3 Modified LMTD Model . . . . . . . . . . . . . . . . . . . . . . . . . 105
3.5 Experimental Investigations. . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
3.6 Industrial Status of Dew-Point Evaporative Air Coolers . . . . . . . 120
3.7 Future Research Direction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
3.8 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
4 Adsorbent-Coated Heat and Mass Exchanger. . . . . . . . . . . . . . . . . . 131
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
4.2 Adsorbents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
4.2.1 Silica Gel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
4.2.2 Zeolites. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
4.2.3 Polyvinyl Alcohol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
4.2.4 Superabsorbent Polymer. . . . . . . . . . . . . . . . . . . . . . . . . 138
4.2.5 Metal–Organic Framework (MOF) . . . . . . . . . . . . . . . . . 139
4.3 Solid Adsorbent Dehumidification Systems . . . . . . . . . . . . . . . . 141
4.3.1 Fixed-Bed Dehumidifier. . . . . . . . . . . . . . . . . . . . . . . . . 141
4.3.2 Rotary Wheel Dehumidifiers. . . . . . . . . . . . . . . . . . . . . . 142
4.3.3 Adsorbent-Coated Heat and Mass Exchanger. . . . . . . . . . 144
4.4 Binders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
4.4.1 Adhesive Ability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
4.4.2 Influence on the Adsorption Uptake . . . . . . . . . . . . . . . . 148
4.4.3 Heat Transfer Performance. . . . . . . . . . . . . . . . . . . . . . . 148
4.5 Adsorbent Coating Techniques . . . . . . . . . . . . . . . . . . . . . . . . . 148
4.5.1 Dip Coating. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
4.5.2 Electrostatic Spray Coating. . . . . . . . . . . . . . . . . . . . . . . 149
4.5.3 Direct Synthesis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
4.6 Dynamic Performance of Adsorbent Coated Heat and Mass
Exchangers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
4.6.1 Average Moisture Removal Capacity . . . . . . . . . . . . . . . 151
4.6.2 Thermal Coefficient of Performance . . . . . . . . . . . . . . . . 152
4.7 Parametric Study of ACHMEs. . . . . . . . . . . . . . . . . . . . . . . . . . 153
4.7.1 Effect of Moisture Content of Air. . . . . . . . . . . . . . . . . . 153
4.7.2 Effect of Inlet Air Dry Bulb Temperature . . . . . . . . . . . . 153
4.7.3 Effect of Face Velocity of Exchanger . . . . . . . . . . . . . . . 155
4.7.4 Effect of Cooling Water Temperature . . . . . . . . . . . . . . . 156
4.7.5 Effect of Regeneration Temperature . . . . . . . . . . . . . . . . 156
4.7.6 Effect of Cycle Time . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
4.8 Hybrid Applications of Heat and Mass Exchangers. . . . . . . . . . . 159
4.8.1 ACHMEs Coupled with Solar Thermal System . . . . . . . . 160
4.8.2 Multi-bed ACHME System . . . . . . . . . . . . . . . . . . . . . . 161