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Advances in Air Conditioning Technologies : Improving Energy Efficiency PDF

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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

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