Volume 6 Issue 2 (2018) 102-107ISSN 2347 - 3258International Journal of Advance Research and InnovationBiomimicry for Innovative Air-ConditioningPaul Gregory F 1,*, Durkesh Karthik P2, Gokul C3, Vignesh M1, Ganesh Kumar R11School of Energy, Department of Mechanical Engineering, PSG College of Technology, Coimbatore, Tamilnadu,India2Volkswagen Coimbatore, Ramani Cars Private Limited, Coimbatore, Tamilnadu, India3Moldwell Products Private Limited, Coimbatore, Tamilnadu, IndiaArticle InfoArticle history:Received 2 May 2018Received in revised form20 May 2018Accepted 28 May 2018Available online 15 June 2018KeywordsThermalComfort;Biomimicry;Bionic; HydrophilicAbstractThe intendment of Air Conditioning lies not just only in removing the heat from a confined space so as toproduce a state of thermal comfort, but also must focus on Energy Efficient processes, parroting the similarstate of Thermal Comfort. Biomimicry is an emerging field of science that imitates nature and applies suchprocess for scientific technologies. In Biomimicry for airconditioning systems, the requirement for energyefficient processes lies in creating a domain of thermal comfort by a process that would eliminate thenecessity for an energy consuming process. Also such bionic inspired systems must be reliable and must notcause further disadvantages. In such a scenario, this work focuses on three main bio-inspirations; A TermiteMound inspired convection currents, Blood Flow in Penguins inspired counter flow heat exchanger systemand the behavior of an insect Brown Dog Tick that secretes an interesting hydrophilic chemical that couldbe used for dehumidification. Various happenings in the three biological processes have been discussed andthe feasibility of such processes to be implemented in technological behavior has been discussed.1. IntroductionAir Conditioning systems play a vital role in the energy behavior ofany building. Researches have estimated that, 65% of the energyconsumed by the building industry is for Heating, Ventilation and AirConditioning (HVAC) [1] and its allied activities. Hence energyefficient HVAC Systems are the necessity for the hour without anycompromise in the operational efficiency and the air qualitymanagement. Energy efficient buildings will definitely be a backbonein the development of any country. Several systems are beingdeveloped to aggrandize the energy efficiency in buildings. Systemslike Unglazed Solar Thermal Facades [2], Phase Change Materials inBuildings [3], Integrated control of natural ventilation and HVACsystems [4], Utilizing Renewable Energy Sources for AirConditioning Systems [5] will definitely prove energy efficient. Insuch a progress in technology, the field of biomimicry is gaininginterest. Biomimicry helps designers to apply concepts andmechanisms that naturally happen around to a complex technologicalprocess that would indeed solve tedious problems. Nature is a sourcefor many designers and architects as the evolution of it takes manyforms, and happenings. Mother Nature has provided human beingswith a myriad source of inspiration to ponder with. Biomimicry isclassified [6] into three categories:1. Organism level Biomimicry2. Behavior level Biomimicry3. Ecosystem level BiomimicryGerhard F. Swiegers [7] describes biomimicry to be a reverseengineering from nature. Wright brothers built a flight after gettingfrom the wings of birds. Hence biomimicry for Air conditioningsystems will definitely prove energy efficient as well as woulddefinitely expound complex phenomena. Several Bionic inspiredsystems are being developed in many parts of the world. A few notablebionic inspired buildings [8] include The Council House, Melbourne The Water Cube, Beijing, The Esplande Theatre, Singapore East Gate Center, Zimbabwe.It is not just with buildings, several technologies are also now beinginspired from biological inspirations. Several bioninc inspired heatexchangers are also being developed that inspires the flow of blood ofblood through arteries and veins [9] and such systems are found to bemore efficient than conventional systems.*Corresponding Author,E-mail-address: [email protected] rights reserved: http://www.ijari.orgFig:1 The Esplande Theatre, Singapore inspired from the skin ofDurian Fruit2. Termite Mound Inspired Air-Conditioning forBuildings2.1 Architecture of Termite MoundFig.2 A Typical Termite Mound at CoimbatoreA typical termite mound is show in Fig.2. Termite build large moundwhere they grow fungus which will serve as a primary source of foodto the termite. The fungus is grown at the bottom of the mound. ATermite mound consists of large number of pores on the surface whichacts as air vents. The air vents in a termite mound is schematicallyshown in Fig.3. Termites constantly close and open selected pores andthis activity is of utmost importance as it is the source of inspirationfor an airconditioning system.2.2 Thermal Behavior of Termite MoundA Termite Mound was taken into consideration located atCoimbatore. Temperature Measurement has been carried out usinginfrared thermometer pointing to the inner of the mound. Temperature102IJARI

Volume 6 Issue 2 (2018) 102-107ISSN 2347 - 3258International Journal of Advance Research and Innovationinside the mound was reported monthly. The variation in temperatureinside the considered temperature mound is shown in Fig.4Air Flow OutAir Flow InVentsFig.3 Air Flow in a Termite Mound (Open Mound)4035302520151050MoundClimaticFig.4 Temperature inside Termite Mound (2018)From Fig.4, it can be inferred that, throughout the year, thetemperature inside the termite mound remains lower than the climatictemperature of the ambient. Such a system can be used in hotter partsof the world where the necessity of the air conditioning system will beon sole cooling of the building. Inside the termite mound, convectionphenomenon is used to keep the temperature lower than theenvironment. Termites constantly close and open certain pores as aregular process throughout the year and this causes air from outside toenter inside the vents and it takes up the heat inside and goes outthrough the vent at the top. This phenomenon takes place throughoutthe year and hence the temperature is maintained lower. Thisphenomenon can be taken as an inspiration for HVAC systems inbuildings. Air from outside can be circulated to the inner of thebuilding and can be exhausted.3. Biomimicry at East Gate Center, HarareThe East Gate Center at Harare, Zimbabwe is a standing witness forinspiration from Termite Mound. The Building uses similarTechnology in ventilation. The building vents the hot air at the top ofthe building. It has fans to drawn in air from the atmosphere at thebottom of the building. The electric fans are generally used at night tosuck in cold air from the atmosphere, expelling hot air out of thebuilding. This will additionally cool the building during night time.The air flow is shown in Fig.5Various benefits that are achieved by using such biomimiced systemare:1. A minimum 30C temperature difference can be achieved betweenthe outside environment and inside environment2. The maximum temperature that is recorded indoors is 260C.3. This system is able to save in the building, about 90% energy thatis consumed by conventional HVAC systems.Fig.5 Ventilation at East Gate Center, HarareVarious technical requirements in the biomimicry of Termite Mounds:1. The Building must be provided with a source of air entry and asource of air exit such that the flow of convection currents infacilitated. Auxiliary systems include fans and diffusers matchedwith the thermal load of the building2. The building must be provided with heat accumulation system ateach room, such that the hot air is raised up to the heataccumulation system and gets vented out. Due to the densitydifference between the hot air and the cold air, the hot air risesabove the cold air and gets accumulated and from theaccumulator must be vented out.3. Facades and vegetation can be enhanced on the building facingdirect solar radiation so as to avoid building from getting heated.This will further enhance the process of achieving ThermalComfort.4. Air quality maintenance systems without any compromise inIndoor Air Quality. Primary methods to improve the air qualityinclude Control at Source, Diluting Contaminants in air usingVentilation. Certain auxiliary methods include removing arearugs and utilizing compact indoor air quality controllers.5. Windows of the East Gate buildings are arranged in such a waythat minimum heat is transmitted through it in summer. Hencesuch designs would be preferred and would further increaseenergy efficiency for buildings attempting the termitebiomimicry.3.1 Comparision of Biomimiced system with ConventionalSystemAs quoted previously, this system saves about 90% of energy that anyconventional air conditioned system when applied to the samebuilding. Thus biomimicry from termite mound proves energyefficient. Further Solar Flat Plate Collectors provided at the top of thefirst building, will pull down the conventional cost of water heating.Hence this will also eliminate unnecessary space occupied bypackaged air conditioning units, Chillers, Cooling Towers and otherrelated accessory components. Conventional Air conditioningsystems for building will need to have special ducts to supply coolair, water circulation pipes if water cooled chiller air conditioningsystems are relied on (Central Air Conditioning), bulky compressorsand heat pumps. But in case of this bionic inspired system alongsideheat accumulation system, the designer will need to channel ducts toexhaust hot air and supply cool air. An upside down chimneychanneled duct is preferred for exhausting hot air. This is taking intoconsideration the thermo physical properties of hot air and also thephysical phenomenon of ventilation.103IJARI

Volume 6 Issue 2 (2018) 102-107ISSN 2347 - 3258International Journal of Advance Research and InnovationAuxiliary supporting systems such as Glass Facades and Vegetationwhen applied for conventional air conditioning systems will producemeager effects on the energy efficiency. Whereas in case of bionicinspired systems, the entire energy efficiency relies on such very smallvicissitudes. Hence addition of such supporting systems will definitelyprove enhancing the energy efficiency thereby reducing HVACenergy consumption.Emissions play an important role in evaluating any component system.It is found in conventional air-conditioning systems that filters are themajor source of pollution and Humidifiers are the major source of odoremissions [10] from any air-conditioning system for building. Thesebionic inspired systems will definitely eliminate such emissions andhence will eliminate the necessity for huge emission control systems.Apart from pollutants, carbon emissions are found to be increasinglydominant in conventional air conditioners. Carbon is a majorcontributor to global warming and its effects and insulates the surfaceof planet earth [11]. The average temperature rise of the earth is 10C[11]. Such bionic inspired technologies would eliminate carbonemissions too.Hence in substantial aspects, this bionic inspired air-conditionedbuilding proves beneficial to conventional air conditioned buildings.Hence proper use of this bio mimicry will definitely prove energyefficient for buildings.In a typical penguin’s foot, arteries that carry oxygenated blood fromthe heart and the veins that carry deoxygenated blood to the heart havea counter current arrangement. The veins that are in contact with thewebbed foot that is in direct contact with the ice have cold bloodcirculation, and this cold blood circulation gets heated by the arteriescarrying warm blood and hence the cold blood in the veins will getwarm before reaching the heart of the penguin. Due to this heatexchange phenomenon the interior core body of the penguin remainswarmer. This blood circulation continues on protecting the penguinfrom getting frostbite. This phenomenon of heat exchange serves as asource of inspiration for many man-made heat exchangers.4.2 Biomimicry of Penguins for Air ConditioningIt would be highly beneficial when such counter current approach isapplied to HVAC units. In the scenario of ground heat exchanger forHVAC System when integrated with counter current approach willdefinitely prove to enhance the efficiency on the bionic approach. Atypical ground heat exchanger for HVAC Systems is as shown in Fig.84.Penguin Foot Inspired AirconditioningThe blood flow in a penguins’ body serves as a source of inspirationfor many thermal engineers. Penguins that live in the AntarcticContinent experience very cold temperature upto -500C. Despite verycold temperatures, they protect their body from frostbite. Thephenomenon behind this activity is with the blood flow in the body.The blood flow for a penguin’s feet is shown in Fig.7AIR INAIRTOHOUSE(HEATING/COOLING)GROUNDFig.8 Simple Configuration of Ground Heat Exchangers for HVACPierre et al [12] has tested such systems and has obtained the positiveresults experimentally. The system is show in Fig. 9 shows theapplicability of bionic inspired counter current heat exchangerapproach.Fig.6 A Typical Penguin’s Feet4.1 Countercurrent Heat Exchange in PenguinsCounter FlowHeat ExchangerVeinsArteriesFig.9 Experimental Configuration by Pierre et al [12]Webbed FootA Computational Fluid Dynamics (CFD) Approach has beenattempted to visualize such systems for Coimbatore region. The soilproperties of Coimbatore region were studied. ANSYS-FLUENTSimulation Tool was used to make the analysis. The followingconditions were applied to the analysis:Fig.7 Blood Flow in a Penguin’s Foot104IJARI

Volume 6 Issue 2 (2018) 102-107ISSN 2347 - 3258International Journal of Advance Research and InnovationTABLE.1 Applied Conditions For CFD AnalysisPipe Diameter (Air Flow)Hence it can be inferred that Bionic inspired technology based onPenguin’s counter flow approach based on blood flow provesbeneficial and energy efficient.0.10mDepth of pipe insertion2mTemperature of soil at the ion From Brown Dog Tick350CTemperature of air inletAir flow VelocityLength of pipe (running inside soil)1 m/s to 10 m/s20mTotal Length of pipe (Entry to Exit)OnBrown dog tick (Rhipicephalus sanguineus) is an insect that hasattracted researchers through its weird behavior. This insect is capableto surviving several days without drinking water. The reason behindthis activity has empowered researchers to apply the technique to airconditioning systems.28mThermal Conductivity of Soil1.8 W/m KHeat Capacity of Soil2 MJ/ m3 KThe results from CFD Simulation have been graphically plotted asshown in Fig. 10 and Fig.11. From Fig.12, it is inferred that optimumair flow velocity is 4m/s. Fig.12 shows that at 4m/s the maximumtemperature that can be achieved for the air conditioner inlet is 260C.This ground heat exchanger is capable of producing a 90C differencein temperature just by passing air flow pipes into the soil. This processis hence highly economical and energy efficient too. On the otherhand, the air from inside is constantly vented to atmosphere. Thecounter flow approach inspired from Penguin’s blood flow willfunction for the following benefits:1.2.As the control of soil temperature is impossible, it is possible topreheat the incoming air in a counter flow configuration tomaintain a region of thermal comfort.Coupling ground heat exchanger with counter flow ventingexchanger will be a source for energy efficiency as it avoidsbulky rotating machinery.Convective Heat Transfer Coefficient (h)25201510Fig.13 A Typical Brown Dog Tick5.1The Hydrophilic AnalogyThe ability of the tick to absorb water vapor from the atmosphereaccredits it to survive for many days, without drinking water. The tickfirst observes and detects a zone of high atmospheric humidity. Afterthe detection process the tick secretes a hydrophilic substance from itsmouth. This hydrophilic secretion absorbs water vapor and thehydrated solution is then withdrawn inside the mouth of the tick. Thusthe tick rehydrates itself without directly getting to drink water. Thereis an analogy between this phenomenon and an activity of airconditioner. Despite the air conditioner’s primary function is to coolthe air to the desired temperature output, the air conditioner will alsodehumidify the air. Dehumidification has to be done to set the righthumidity levels to the output air.5.2Conventional Dehumification Process5012345678910Fig.11 Variation in Convective Heat Transfer CoefficientAir Temperature40Soil TemperatureConventional vapour compression airconditioning system rely ondehumidification by cooling and condensation [14]. When fresh airthat is sucked into the air conditioner is cooled beyond its Dew PointTemperature, it will condense and finally the moisture in the aircomes out as water droplets. Lower the temperature of the coolingcoil, drier will be the air. Achieving the Dew Point Temperature inthis case is an important parameter to be considered in this activity.The process occurring in a conventional airconditioner is as show inFig.1335AIR ENTERS TO THE AIRCONDITIONER302520EVAPORATOR /COOLING COIL1510WATERDROPS50REHEATING COILAIR TO OTHER SYSTEMS / LOADFig.12 Variation in Temperature at 4m/sFig.13 Scheme in Conventional Air Conditioners105IJARI

Volume 6 Issue 2 (2018) 102-107ISSN 2347 - 3258International Journal of Advance Research and InnovationFig.15 Desiccant based DehumidificationFig.14 Conventional Cooling and Dehumidification Process inPsychrometric ChartFrom Figure.14, it can be noted that: Process A – B: Cooling and Dehumidification. Process: B-C: Reheating Process5.3 Inspiration from the Tick’s activityFrom the tick’s activity one would find that using chemicals thatwould absorb moisture from air would definitely be energy efficientin a long term process. But the challenge in using such solutions liesin the saturation point of that chemical being used, hence the designmust also incorporate so as to generate and regenerate the hydrationprocess. Also the interaction of such chemical used to removemoisture with the environment must also be noted. And above allthe life of such systems must be noted. Such chemical integratedsystems are termed as desiccant based system. In such systems twomain phases [13] are to be undertaken in the activity.1.Desiccant Dehumidification Process2.Regeneration of the Desiccant3.Such desiccants systems can be classified [13] into two categories:1.2.Solid Desiccant DehumidificationLiquid Desiccant Dehumidification5.3.1 Configurations to incorporate HydrophilicDesiccants to the system.Several configurations are being developed to incorporate suchdesiccants to the airconditioning unit. Some notable configurationsinclude:1. Rotary desiccant Dehumidifiers [14]2. Heat Pump Driven Desiccant Dehumidifiers[14]3. Falling liquid desiccant film on finned-tubes [15]4. Membrane based dehumidification[16]5. Circulating inclined fluidized beds with application fordesiccant dehumidification systems [17]6. Renewable Energy Systems integrated DesiccantDehumidification systems [18]Some suitable desiccants that could be used to enhance this bionicbased activity are as:1.Lithium Chloride [19]2.Lithium Bromide [19]3.Calcium Chloride [19]4.Activated Carbon and Methanol [20]5.Graphene Oxide Membranes [21]6.Modified and Unmodified Silica [22]7.Metal Oxide [22]In Fig.15, Process A – B indicates the desiccant based dehumificationprocess. When compared with Fig.14, it can be noted that thedessicant dehumidification process is comparatively better comparedwith conventional methods of dehumdification(cooling andcondensation).5.4 Applicability of this Bionic inspired SystemThis bionic inspired system is best fitted to a system where the air iscold, atleast below 80C and is humid. This system will also hold goodwhen very low Dew Point Temperatures are required [13]. Wheneverany renewable energy source is available, this bionic inspireddesiccant cooling system is preferred as it would further reduce theenergy requirement in regeneration of desiccants. This desiccant basedsystem will be best suited for buildings that have a cold storage unit tostore food grains, dairy products, vegetables where the humiditycontrol will be an important criterion. Hence, such bionic inspired airconditioning system would definitely prove beneficial. Elimination ofa few processes in conventional air conditioning will definitely makethis Insect Brown Dog Tick inspired system energy efficient andwould improve the quality of the process.6.ConclusionsNature has provided with multitudinous resources not just to ponderwith, but also to learn from her. In this article, three inspirations fromnature have been discussed. This work is just an exemplification ofnature’s contribution to improve technological processes. When anytechnology is made to operate taking a tip from nature, woulddefinitely satisfy the needs of any engineer; energy efficiency,economy and reliability. It is upto the technically termed ‘homosapiens’ to use Nature in a fruitful way paving ways ahead for theforthcoming generations.ReferencesG Gong, J Liu, X Mei. Investigation of Heat Load, Calculationfor Air Carrying Energy Radiant Air-conditioning /j.enbuild.2016.12.005[2] J Shena, X Zhang, T Yang, L Tang, H Shinoharaa, Y Wub, HWang, S Panc, J Wu, P Xu. Experimental study of a CompactUnglazed Solar Thermal Facade (STF) for Energy-efficientBuildings, Energy Procedia 104, 2016, 3 – 8.[3] BP Jelle, SE Kalnæs. Cost-Effective Energy-Efficient BuildingRetrofitting, ISBN: 978-0-08-101128-7, 2017, 57-118.[1]RZ Homod, KSM Sahari, HAF Almurib. Energy Saving byIntegrated Control of Natural Ventilation and HVAC Systemsusing model guide for comparision, Renewable Energy 71,2014, 639-650.[5] R Lathia, J Mistry. Process of designing efficient, emission freeHVAC Systems with its components for 1000 seats auditorium,Pacific Science Review A: Natural Science and Engineering2016,1-14[4]106IJARI

Volume 6 Issue 2 (2018) 102-107ISSN 2347 - 3258International Journal of Advance Research and [17][18][19][20][21][22]MS Aziz, AY El sherif. Biomimicry as an approach for bioinspired structure with the aid of computation, AlexandriaEngineering Journal 55, 2016,707-714.GF Sweigers. Bioinspiration and Biomimicry in Chemistry, AJohn Wiley and Son Inc. Publication, 2012.GAN Radwan, AN Osama. Biomimicry, An Approach forEnergy Efficient Building Skin Design, Procedia EnvironmentalStudies 34, 2016, 178-189.A Kremers, M Pieper. Simulation and Verification of BionicHeat Exchangers with COMSOL Multiphysics, Proceedings ofCOMSOL Conference, Grenoble, 2015.F Bitter, K Fitzner . Odour Emissions from an HVAC System,Energy and Buildings 34, 2002, 809-816.R Kumar, RK Aggarwal, D Gupta, JD Sharma. CarbonEmissions from air-Conditioning, American Journal ofEngineering Research (AJER) 2, 2013, 72-74P Hollmuller, B Lachel. Air-soil Heat Exchangers for heatingand cooling of Buildings: Design Guidelines, Potentials andConstrains, System Integration and Global Energy Balance.Applied Energy 119, 2014, 476-487K Singh, R Thakur. Hybrid (Desiccant Conventional)Dehumidification Air Conditioning: A Less ExploitedTechnology, IJRMET 03, 2013,198-201KS Rambad, PV Walke, DJ Tidke. Solid DesiccantDehumidification and Renegeration Methods – A Review,Renewable and Sustainable Energy Reviews 59, 2016, tRegeneration Process by a Falling Liquid Desiccant Film onFinned Tubes for Different Flow Arrangements, InternationalJournalof Thermal Sciences 113, 2017,10-19Z Chen, J Zhu, H Bhi, Y Yan, L Zhang. Experimental Study ofa membrane based dehumidification cooling system, AppliedThermal Engineering, 2016.YC Chiang, CH Chen, YC Chiang, SL Chen. CirculatingInclined Fluidized Beds with application for DesiccantDehumidification Systems, Applied Energy 175, 2016, 199-211U Eicker, D Schneider, J Schumacher, T Ge, Y Dai. OperationalExperiences with Solar Air Collector driven Desiccant CoolingSystems, Applied Energy 87, 2010, 3735-3747MM Rafique, P Gandhidasan, HMS Bahaidarah. LiquidDesiccant Materials and Dehumidifiers – A Review, Renewableand Sustainable Energy Reviews 56, 2016, 179-195YJ Dai, RZ Wang, YX Xu. Study of a solar powered solidadsorption– desiccant cooling system used for grain storage,Renewable Energy 25, 2002, 417–430Y Shin, W Liu, B Schwenzer, S Manandhar, DC Woods, MHEngelhard, R Devanathan, LS Fifield, WD Bennett, B Ginovska,DW Gotthold. Graphene oxide membranes with highpermeability and selectivity for dehumidification of air, Carbon,2016, doi: 10.1016/j.carbon.2016.05.023.F Tang, QW Yu, BF Yuan, YQ Feng. Hydrophilic Materials inSample Pretreatment, Trends in Analytical Chemistry, 2016,doi: 10.1016/j.trac.2016.10.007.107IJARI

Volume 6 Issue 2 (2018) 102-107 ISSN 2347 - 3258 International Journal of Advance Research and Innovation 102 IJARI Biomimicry for Innovative Air-Conditioning Paul Gregory F 1,*, Durkesh Karthik P2, Gokul C3, Vignesh M1, Ganesh Kumar R1 1School of Energy, Department of Mechanical Engineering