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中英文翻译-在汽车中热化阶段和冷却阶段的热舒适性,中英文,翻译,汽车,热化,阶段,冷却,舒适

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ORIGINALO. Kaynakli E. Pulat M. KilicThermal comfort during heating and cooling periods in an automobileReceived: 9 September 2003/Published online: 17 September 2004? Springer-Verlag 2004Abstract Most vehicles have a heating, ventilation andair conditioning (HVAC) device to control the thermalenvironments of interior of the vehicle. But, under hotsummer season or cold winter conditions, it is difficult toachieve and maintain thermal comfort in an automobilefrom the start up to the steady-state conditions. Duringthese transition periods, an understanding of humanthermoregulatory processes facilitates the design anddevelopment of improved heating and cooling systems.This study presents a model of thermal interactionsbetween a human body and the interior environment ofan automobile. The model is based on the heat balanceequation for human body, combined with empiricalequations defining the sweat rate and mean skin tem-perature. Simulation has been performed by the use oftransient conditions. The effects of both heating andcooling processes on the thermal comfort inside theautomobile are investigated. Results are compared withthe present measurements and available experimentaldata in the literature. It is shown that the agreementbetween the experimental data and the model is verygood.List of symbolsAsurface area, m2cpspecific heat, J/(kg K)CSIGcold signalfcorrection factorhheat transfer coefficient, W/(m2K)isegment numberjair or fabric layers numberkconductiveheattransfercoefficient,W/(m K)Lheat load, W/m2mbody mass, kg_ mmass flow rate from per unit area, kg/(s m2)Mmetabolic heat production rate, Wnlnumber of layers covering segmentpwater vapor pressure, kPaQheat transfer rate, Wrouter radius of fabric layerRthermal or evaporative resistance, (m2K)/Wor (m2kPa)/WSheat storage, Wttime, s (unless specified in minutes)Ttemperature,?CTSthermal sensationVair velocity, m/swskin wettednessWhumidity ratio, kgH2O/kg dry air_ Wexternal work rate accomplished, WWSIGwarm signalxthickness, mmGreek symbolsaratio of skin layer mass to total body massgpermeation efficiencySubscriptsaairalair layerbbodyblbloodcdconductionclclothingcrcorecvconvectiondifdiffusioneexposed to convective and radiant environmentevevaporationO. Kaynakli E. Pulat M. Kilic (&)Faculty of Engineering and Architecture,Department of Mechanical Engineering, Uludag University,Gorukle Campus, 16059 Bursa, TurkeyE-mail: .trTel.: +90-224-4429183Fax: +90-224-4428021Heat Mass Transfer (2005) 41: 449458DOI 10.1007/s00231-004-0558-9exexhaledffabricintinterface between outer clothing surface and asolid (such as the seat or back support)maxmaximumnneutralresrespirationrdradiationssaturatedskskinswsweatttotal1 IntroductionThe comfort of the driver and passengers in a vehicle ispartially dependent on the quality and temperature ofair in the vehicle. Three interrelated systems are used toprovide the desired air temperature and quality. Theseare the ventilating system, the heating system and the airconditioning system. The purpose of the heating, venti-lation and air conditioning (HVAC) system of a vehicleis to provide complete thermal comfort for its occu-pants. Hence, it is necessary to understand the thermalaspects of the human body in order to design an effectiveHVAC system.In order to estimate the thermal comfort level,accurate information on the thermal environment isessential. The thermal environments can be roughlyrepresented by the temperature, velocity and humidity inthe automobile interior. In this interaction, heat andmass transfer take place together. Complete model ofhuman comfort consist of energy balances, equations forthe thermophysical properties of the fluids and materi-als, and heat and mass transfer characteristics.The passenger compartment of an automobile isheated in the winter months by circulating hot enginecoolant through a coolant-to-air heat exchanger thatwarms the compartments air. The heating system isdesigned to operate in conjunction with the air venti-lating system to provide the desired air temperature.With progressive reductions in engine size, stemmingfrom considerations of fuel economy, and correspondingreductions in the heat available for the passenger heatingsystem, there is interest in the development of moreeffective systems to ensure passengers thermal comforteven in extreme conditions by considering market situ-ation. It is difficult to achieve and maintain passengerthermal comfort under extremely hot or cold drivingconditions. Some auxiliary heating or cooling apparatusmay greatly reduce the time needed to attain thermalcomfort. But, power requirements associated with thisapparatus are substantial.In hot season, air conditioning units are used. Whenair conditioning is mentioned, the first thought thatcomes to mind is cooling and, refreshing of air. Actually,the automobile air conditioning system not only coolsthe air but also cleans, dehumidifies, and circulates itfor the health and comfort of the passengers. Theseprocesses are performed by working in conjunction withthe heating and ventilating systems.Human thermal comfort has been the subject ofconsiderable previous study, and much of the availableinformation documented and codified 3. In the litera-ture, most of the studies have considered the thermalconditions are nearly uniform and steady over the entirebody of occupant. Less attention appears to have beendirected to comfort in an automobile, where conditionsare highly nonuniform and transient over the body ofthe occupant.Yig it 18 is to calculate the heat loses for each bodysegments and total loss for the whole body for five dif-ferent clothing ensembles. However heat losses from theparts of the body were not considered and clothingresistances were not evaluated for the thermal comfort.McCullough et al. 13, 14 published the insulationvalue, evaporative resistances of representative cloth-ing ensembles that were measured with a thermalmanikin. These parameters were also measured forcomponentfabricsusingasweatinghotplateapparatus. A computer model was developed thatestimates the resistance to dry and evaporative heattransfer. Olesen et al. 15 studied five different cloth-ing ensembles with the same total thermal insulation,but very different distributions of the insulation on thebody in experiments with 16 sedentary subjects. Theasymmetry was ranging from nude upper part to nudelower part of the body. Their experimental study willprovide a method for quantifying the nonuniformityof a clothing ensemble and examine how it influenceslocal thermal discomfort.Tanebe et al. 16, investigated sensible and latentheat loss from several parts of the human body by theuse of a manikin. For each considered part of thebody, total heat transfer coefficient and thermal resis-tance were found. Since their study was performed inconstant temperature environment, it did not give anyresult about the thermal comfort. Kaynakli et al. 11reported a study in which the human body is dividedinto 16 sedentary segments, a computational model ofthermal interactions between each of 16 body segmentsand the environment is developed. By the use of themodel, skin wettedness and latent (sweating, diffusion)and sensible (conduction, convection, radiation) heatlosses from each body segment and whole body arecalculated for both sitting and standing postures.Kaynakli et al. 12 presented a numerical model of theheat and mass transfer between the human body andthe environment. In their study, the required environ-mental and personal conditions for satisfaction of thepeople obtained under steady-state conditions, andtotal sensible and latent heat losses, skin temperature,wettedness, predicted mean vote (PMV) and predictedpercentage of dissatisfied (PPD) values were calculatedvia simulation.450Chakroun and Al-Fahed 7 presented a study ofthe temperature variation and thermal comfort insidea car parked in the sun during the summer months inKuwait. They also considered the effect of using dif-ferent combinations of internal covering on the tem-perature inside the car. Burch et al. 4 reported theresults of a series tests on passenger thermal comfortduring warm-up under severe winter driving condi-tions. They found that low-power electric heating padsinstalled on the seat and back support greatly reducethe time needed to attain thermal comfort. Furtherreductionsinwarm-uptimecanbeachievedbyinstalling electric heaters in the air ducts, although thepower requirements associated with this method aresubstantial. In addition to their experimental study,they presented an analytical study on this subject inthe paper of Burch et al. 5.Heating and cooling periods from the start up ofthe vehicle require some time to reach steady-stateconditions. During these periods, conditions are highlynonuniform over the body of the occupant. Thevehicle passenger experiences localized chilling due tocontact with an initially cold seat or steering wheel,nonuniform radiant heat transfer with the surround-ings, localized solar irradiation, and nonuniform airvelocities that vary depending on the location of theair registers and dashboard control settings. Thus, inaddition to the air temperature, several other factorshave a bearing on the thermal comfort of the pas-senger. Consequently, there is substantial interest inthedevelopmentofmoreefficienttechniquesforachieving and maintaining passenger thermal comfortin an automotive environment.This study presents a model of thermal interactionsbetween a human and the interior environment of anautomobile.Since,segmentalanalysispermitsthedetermination of local discomforts by considering theclothing insulation asymmetry effects in the relativelysmall volumes such as automobile cabin, the presentmodel is based on the heat balance equation for humanbody by dividing it into 16 segments. By combiningGagge et al.s 10 and Olesen et al.s 15 approaches,all body segments are considered as two-concentriccylinders and required new data such as surface areasof body segments and their masses are refined from theexisting literature. In this way, apart from the Gaggeet al.s 10 model, it is tried to determine the localdiscomforts by calculating the thermal interactions ofeach segment and the skin temperature and wettedness.Simulation has been performed by the use of transientconditions. The effects of both heating and coolingprocesses on the thermal comfort inside the automobileare investigated. Experiments were also conducted forcooling periods. Until the thermal comfort reached inthe automobile compartment, the temperature and thehumidity changed dramatically. Driver and passengersare greatly affected by these changes. The simulationresults and experimental data were compared, in orderto validate the present model.2 Mathematical modelThe velocity of conditioned air that flow over passengeris very important from comfort point of view in smallcompartments that have large heating and coolingcapacity especially such as automobile cabin. Flowingair over driver and passengers injected by inlet vents hasnot same value on any occupants body. Although it is agood approximation to take average velocity for typicalindoor conditions, this results important mistakes byconsidering automobile interior. Local air velocities onthe body of sitting passenger were determined experi-mentally by Burch et al. 5 (Table 1). In this study,determination of heat losses from various regions ofpassenger is based on these velocity values.The model used in this study is based on the sameapproach described in the study of Olesen et al. 15. Inthis study, human body is divided by 16 regions byconsidering clothing groups and local air velocities onthe body in order to investigate the effects of thermalenvironment to occupants especially driver in detail forboth winter and summer condition. In Table 2, surfaceareas and their fractions of total body surface area aregiven.To compute temporal temperature variations byusing stored energy in the body segments it is requiredthe masses of these segments. The masses of body seg-ments and their fractions of the total body mass areshown in Table 3.By considering the human body as whole, mean skintemperature gives an idea from thermal comfort point ofview but the temperatures of the extremities such ashand, foot and face or naked parts of human body mayincrease or decrease unwanted values. By using thedeveloped model, time rate of changes of the parametersthat affect the thermal comfort such as sensible andlatent heat losses each of 16 regions, skin temperaturesand skin wettedness may be examined.2.1 Thermal and physiological modeling of human bodyA two-compartment transient energy balance modeldeveloped by Gagge et al. 10 represents the body astwo concentric cylinders the inner cylinder represents theTable 1 Local air velocities on the body 5RegionAir velocity(m/s)Head0.13Trunk0.11Right shoulder0.12Left shoulder0.13Legs0.11Right knee0.18Left knee0.21Right ankle0.66Left ankle0.62451body core (skeleton, muscle, internal organs) and theother cylinder represents the skin layer. This model, byconsidering instantaneous heat storage of the core andthe skin compartment, assumes that temperatures ofthese compartments change with time. The thermalmodel is described by two coupled heat balance equa-tions, one applied to each compartment 3:Scri Mi ? 7pt _ W i ? Qresi Qcr;ski?1Sski Qcr;ski ? Qcdi Qcvi Qrdi Qevi2where, M rate of metabolic heat production, 7pt _ W rateof mechanical work accomplished, Qrestotal rate ofrespiratory heat loss, Qcr,skrate of heat transport fromcore to skin, Qcn, Qcv, Qrdrate of heat loss from skin toenvironment by conduction, convection and radiationrespectively. Scrand Sskthat denotes stored energies incore and skin layer causes instantaneous temperaturechanges in these compartments. These effects are ex-pressed with following equations:dTcridtScri1 ? a micp;b?3dTskidtSskiamicp;b?4where m is the body segment mass, cp,bis the specificheat of the body. Qcvand Qrdterms in Eq. 2 are the heattransfers with convection and radiation and can be cal-culated with following relation:Qcv Qrdi Tski ? Toi AeiRcli 1=hcvi hrd fcli?5where, Aeis the surface area of the body segmentsexposed to the environment (total area minus the area incontact with seat, back support, etc.), fclis the ratio ofthe surface areas of the clothed body and the nude body.Operative temperature value (To) that includes averageradiation and ambient air temperature is given asfollows:Toi hrd?Trd hcviTahrd hcvi6For radiative heat transfer coefficient the value of4.7 W/(m2K) is used since it is sufficiently accurate forinternal conditions 3 and convective heat transfercoefficient values of each segment of the body are takenTable 2 Surface areas of the body segments 15Body segments Segment number Surface area m2 Fraction of total body surface area % Left foot 10.062 3.5 Right foot 20.062 3.5 Left fibula 30.140 8.0 Right fibula 40.140 8.0 Left thigh 50.160 9.1 Right thigh 60.160 9.1 Pelvis70.0804.6Head80.18010.4Left hand 90.050 2.9 Right hand 100.050 2.9 Left forearm 110.062 3.5 Right forearm 120.062 3.5 Left upperarm 130.077 4.4 Right upperarm140.077 4.4 Chest150.18510.6Back160.20411.7The whole body 1.751 100.0 Table 3 Mass of the body segments 17BodysegmentsSegmentnumberMass(kg)Fraction of totalbody mass (%)Foot121.161.45Fibula343.724.65Thigh568.0010.00Pelvis76.788.48Head86.488.10Hand9100.480.60Forearm11121.281.60Upperarm13142.242.80Trunk151632.9841.22The whole body80.00100.00452as described in de Dear et al. 8. The total latent heatloss from the skin due to evaporation, Qev, is given byQevi wi psk;si ? pa?AiRcli=gclLR 1=hcvi fcli LR7where, w is the wettedness ratio, psk,sis the saturatedwater vapor partial pressure at the skin temperatureand pais the water vapor partial pressure in theambient air, gclis permeation efficiency of the clothingand LR is the Lewis Relation which is the ratio of theevaporative heat transfer coefficient to the convectiveheat transfer coefficient. McCullough et al. 14 havebeen found an average value of gcl=0.34 for commonindoor clothing.The total skin wettedness (w), includes wettednessdue to regulatory sweating (wsw) and to diffusionthrough to skin (wdif) is given bywswi hfg_ mswiQev;maxi8wdifi 0:06 1 ? wswi9wi wswi wdifi10Maximum evaporation potential, Qev,maxoccurs whenthe skin surface is completely wetted (w=1).In an automobile, a significant portion (1520%) ofthe body surface area is in contact with a seat, backsupport and steering wheel 5. This portion does notlose heat by convection and radiation. The heat lossfrom the skin due to conduction is given byQcdi Tski ? TintRcliAcdi11In the two-node model, heat exchange between thecoreandtheskinoccursbydirectcontactandthrough the skin blood flow. A constant averagethermalconductance,Kcr,sk=5.28 W/(m2K)isas-sumed over the body. The heat flow from core to skinis as follows:Qcr;ski Kcr;sk cp;bl_ mbl?Tcri ? Tski Ai12The specific heat of the blood, cp,blis 4,187 J/(kg K).Respiratory heat loss is approximately 10% of total heatloss 9. The heat loss due to respiration is given byQres _ mrescp;aTex? Ta hfgWex? Wa?Ab13where _ mresis the mass flow rate of air inhaled, Texand Taare the exhaled air and the ambient air temperatures,respectively. Wexand Waare the exhaled air and theambient air humidity ratio, respectively. The heat ofvaporization (hfg) is 2.43106J/kg._ mres 2:58 ? 10?6?M14Tex 32:6 0:066Ta 32Wa15Wex 0:0277 0:000065Ta 0:2Wa16The ratio of the skin mass to total body mass (a) ismodeled as the following function of core to skin bloodflow:a 0:0418 0:7453;600 _ mbl 0:58517The blood flow between the core and the skin per unit ofskin area is expressed as_ mbl6:3 200WSIGcr= 1 0:5CSIGsk?3;60018The rate of sweat production per unit of skin area isestimated by_ msw 4:7 ? 10?5WSIGbexpWSIGsk10:7?19The average temperature of human body can be pre-dicted by the weighted average of the skin and coretemperatures:Tb aTsk 1 ? aTcr20The neutral body temperature is calculated from theneutral skin and core temperatures in the same man-ner.The body is divided into 16 segments which are uni-formly clothed. The total thermal resistance and thetotal evaporative resistance for each segments are asfollows 14:Rti Rairi;0ri;nlXnlj1Rali;jri;0ri;j ? 1 Rfi;jri;0ri;j?21Rev;ti Rev;airi;0ri;nlXnlj1Re;ali;jri;0ri;j ? 1 Re;fi;jri;0ri;j?22It is assumed that heat transfer through air layersbetween clothing layers occurs by conduction and radi-ation. In this case, thermal resistance of an air layer isgiven byRal1hrd k=xa23where xais air layer thickness. The values of hrdand kwere taken as hrd=4.9 W/(m2K) and k=0.024 W/(mK)14. Similar equation can be written for the evaporativeresistance. Evaporative resistance of an air layer is givenby:453Rev;al a 1 ? exp?xab?hi24where a and b are constants. The values of a and b are0.0334 (m2kPa)/W and 15 mm, respectively 14. Theouter surface exposed to the environment is treated alittle differently. The thermal resistance of the outerlayer is then:Ra1hcv hrd25The evaporative resistance of the outer layer can bedetermined from the convective heat transfer coefficientand the Lewis Relation:Rev;a1hcvLR262.2 Prediction of thermal sensationThe above equations describe thermal exchange betweenthe human body and the environment and thermoregu-latory control mechanisms. Combination of the thermalenergy on the body, thermal load, affects the humanthermal comfort in the thermal energy exchange (tran-sition) between the body and its environment. If thethermal load (L) on the body is nearly zero, then neu-trality or thermal comfort is achieved. Combinations ofactivity, clothing and the four environmental variables(air temperature, mean radiant temperature, air velocityand humidity) all affect thermal comfort. The mostwidely used thermal comfort index is the thermal sen-sation (TS) value is given by Eq. 27.TS 0:303exp?0:036MAb? 0:028?L27where Abis the total surface area of the body. The TSscale is given in the Table 4.2.3 Assumptions and initials conditionsNude body surface area is taken as Ab=1.751 m2. Bodymass (m) is 80 kg and initial values of core and skintemperatures are taken as 36.8 and 33.7?C respectively3.Summer clothing insulation, winter clothing insula-tion, clothing area factor for summer clothing, clothingarea factor for winter clothing and metabolic activity aretaken as 0.5 clo, 1.5 clo, fcl= 1.1, fcl= 1.15 and75 W/m2, respectively 5, 6.Table 4 Scale of TS values0 thermal neutrality1 slightly warm?1 slightly cool2 warm?2 cool3 hot?3 cold4 very hot?4 very cold5 painfully hot?5 painfully coldFig. 1 Automobile interior air temperature during heating processFig. 2 Temperatures inside the automobile and human bodycontact surfacesFig. 3 Relative humidity values during cooling process inside theautomobile454Local air velocities on the body is given in the Table 1and mean air temperature (Ta) for heating and coolingprocesses is taken as given in Figs. 1 and 2. Relativehumidity in heating period is taken as 0.35 5 and incooling period it is taken as given in Fig. 3. Meanradiant temperature in heating period is taken as?Trd 0:94Ta? 1:38 and in cooling period is taken as?Trd ?0:007752T2a 1:625778Ta? 6:879288:Surface temperatures of solids in contact with thebody (Tint) in heating period (t is time from start-up inminutes) were 5:SeatTint 41 1 ? exp?t4? 20for t ? 15Tint 20 0:367t ? 15for t 15Clothed area in contact with seat: 0.07 m2Back supportTint ?20 30tfor t ? 1Tint 14:61 ? exp ?t ? 15? 10for 1t10Tint 22:2 0:065t ? 10for t ? 10Clothed area in contact with back support: 0.07 m2Steering wheelTint 40 1 ? exp?t6? 20Clothed area in contact with steering wheel: 0.01 m2.In cooling period, surface temperatures of solids incontact with the body (Tint) are found as follows as aresult of performed experiments. (where t is in minutes)(Table 5).Tint at2 bt c283 Results and discussionsIn order to investigate the effects of automobile interiorconditions resulted by heating and cooling process, theequations given in Mathematical model section areconducted to computer medium by using the program-ming language Delphi 6. For heating period, requiredexperimental input data such as automobile interior airtemperature and humidity, mean radiant temperature,seat, back support and steering wheel surface tempera-tures are taken from Burch et al. 5. In their experi-mental studies, interior air has been heated from ?20 to20?C as seen from Fig. 1.Table 5 Constants in the Eq. 28For t 2For t2abcabcSeat3.10?15.3065.200.0051?0.387046.0496Back support2.55?13.6562.100.0049?0.330643.7763Steering wheel2.50?16.0067.000.0064?0.461844.6285Fig. 4 Comparison of body heat losses in heating processFig. 6 Average body skin temperature in heating processFig. 5 Comparison of thermal sensation during heating process455Required experimental data for cooling process aremeasured in 1991 Toyota Corona Sedan automobileequipped with a 2,000-cc engine. Automobile is parkedin the sun and it is observed that the increase of tem-perature inside car is 64?C with the ambient temperatureof about 30?C. Later, standard cooling process is startedby running the air conditioning unit. During this processtemperature inside car, relative humidity, seat, backsupport and steering wheel surface temperatures aremeasured. Measured parameters are shown Figs. 2 and3. Since relative humidity decreases from 50 to 11%during the increase of temperature inside car to 64?C,relative humidity in cooling process is started from 11%.Heat losses from body to the environment duringwarm-up process are given in Fig. 4 comparatively.Since the model of Burch et al. 5 and the present modelexhibit some principal differences (e.g., the body isdivided into four segments in Burchs et al. 5 model,whereas it is divided into 16 segments in our model.),some discrepancies appear at the beginning period.Apart from this relatively small time interval, theagreement between the results can be acceptable range.Conduction heat losses to the seat, back support andsteering wheel is rather low in comparison to the totalvalue of convective and radiative heat losses because theareas of body segments in contact with solid surfaces aresmaller than other body surfaces. In the beginning ofwarm-up process, conductive, convective and radiativeheat losses are high since the temperature inside theautomobile and the interior surface temperatures arerather low. Even total of these heat losses are higherthan metabolic heat generation. For this reason, coreand skin temperatures of the body a little decreases. But,the decrease in skin temperature is higher than the de-crease in core temperature. It is observed that rapiddecrease in these heat losses due to increase in the tem-perature inside the automobile. In this process, bodytries to keep respiration and evaporation heat losses inminimum to balance heat losses.Comparative variation of TS values in warm-upperiod is given in Fig. 5. By inspection of Fig. 5, there isa good agreement with the study of Burch et al. 5.These calculations are performed by considering thesame conditions described in the experimental andanalytical studies of Burch et al. 4, 5. In their experi-ments, TS values were obtained by using jury data, andthe mean TS and standard deviation (r) of the jury datawere calculated versus time. The present study calcula-tions are fall within the range of TS1r, and the valueof r is given as 0.62. In the beginning, time heat lossesfrom the body to the environment is very high due tolow temperature inside the car. For this reason, TSindices that considers thermal load on the body has beenstarted from very low values. And then, TS hasimprovedwithincreasinginsidetemperatureandinterior surface temperatures.One of the parameters that indicate the effects ofenvironmental conditions on human comfort during thewarm-up period of automobile cabin is mean body skintemperature and its variation with time is shown inFig. 6. In early minutes, average skin temperatureinstantly decreases due to very low temperatures of bothinside the car and interior surfaces. Since temperatureinside car increases with time, mean skin temperatureincreases after its values drops a minimum value ofFig. 7 Temperature of body parts that contact with solid surfacesin heating processFig. 8 Heat flow between body and environment in cooling processFig. 9 Variation of thermal sensation during cooling process45632?C. Although average skin temperature gives an ideaabout the human comfort condition, it must be paidattention local discomforts on human body. The tem-peratures of back, thigh and hand of the body thatcontact with solid surfaces are given in Fig. 7. Thetemperatures of back and thigh are not much moreaffected from inside temperatures, and so they dontvaryimportantly.Butthehand-skintemperaturedecreases to a value of 17.5?C that can be evaluated as arather low temperature. In literature, it is mentionedthat hand-skin temperature of 20?C causes a report ofuncomfortably cold; and 15?C, extremely cold 3.Heat transfer from the body in cooling process isgiven in Fig. 8. Since inside temperature and interiorsurface temperatures are high at the beginning, sensibleheat flow (conduction, convection and radiation) occursfrom environment to the body. This situation contrib-utes to increase in core and skin temperatures. To con-tinue vital functions and in addition to ensure comfortconditions, the heat from environment to body andmetabolic heat generation of body must be emitted toenvironment. For this reason, body increases the sweatgeneration, and then a large portion of the body iscovered by sweat. In this way, evaporative heat loss in-creases as shown in Fig. 8. Whereas respiration loss isnot affected by ambient conditions and it stays about10 W.The variation of TS for cooling period is givencomparativelywithChakrounandAl-Faheds7study in Fig. 9. In Chakroun and Al-Faheds 7paper, detailed ambient conditions were not given, soour model could not be applied directly to theirmeasurement conditions. Therefore, this figure presentsonly a qualitative comparison. In their study, it isensured the temperature inside car reaches up toapproximately 65?C by parking in the sun. Then,cooling process is investigated by running the A/Cunit. But experiments are performed in relatively hotclimateandambienttemperatureisabout45?C.However it is about 30?C in our experiments. And theradiation from the sun is also stronger than our cases.For this reason, temperature profile inside the car isdifferent and depending on this TS values are alsodifferent. In early minutes, due to high inside tem-peratures, heat is transferred from environment to thebody by conduction, convection and radiation. Forthis reason, since the body has a significant thermalload, TS starts from very high values. Then, thermalload decreases with decreasing the temperature insidecar and the surface temperatures and comfort condi-tion gets better.The variation of mean body, feet, and hand-skintemperatures during the cooling process is given inFig. 10. In early times, since the temperature insidethe car is very high (?64?C), the temperatures of theall body segments rise. But, the temperature rise of thehand that directly contacts with air is higher thanother segments. Since inside the car cools with timethis rise decreases. Hands are most affected fromambient conditions, so obvious decrease in tempera-ture occurs on hand. Similar situation is valid forhead. Since shoes are important insulation element,feet are not affected from the interior temperaturevariations. For this reason, the highest temperature atthe end of cooling process occurs at feet. Mean skintemperature of the body varies between hand and feettemperatures.One of the important parameters that affect thecomfort sensation is skin wettedness and its variationwith time is given in Fig. 11. At the early stage ofcooling process, since temperature inside car is high,sweat generation rate is increased to increase heat lossfrom body. So skin wettedness on the body increases.The most rapid increase occurs at feet due to shoes.Since there is no clothing that prevents evaporation ofsweats on the head, and hands that do not contact withsteering wheel, the skin wettedness is the lowest on theseparts of the body. Whereas mean body skin wettednessrises to the maximum value of 0.6 between the wetted-ness of head and feet.Fig. 10 Mean body, hand and feet skin temperatures duringcooling processFig. 11 Mean body, hands and feet skin wettedness in coolingprocess4574 ConclusionsIn this study, the effects of interior environmentalconditions on the human physiology and comfort inheating and cooling processes are introduced. Basicheat exchange equations and empirical relations thatexpress thermoregulatory control mechanisms are usedin heat and mass transfer between human body andenvironment. During these processes, by consideringtemperature and relative humidity inside car and thetemperatures of solid surfaces that contact with body,variations of heat transfer, body segments skin tem-peratures and wettedness and TS values are given.In early minutes of warm-up period, heat loss frombody to environment is very high due to low inside airand surface temperatures. During this time, evaporativeheat losses are kept at minimum by thermoregulatorycontrol mechanisms of body. The average skin temper-ature of the body falls to 32?C and contact temperatureof hand with steering wheel also falls to very low valueas 17.5?C. Since it becomes important heat loss frombody to environment, TS has been started from ?4.5,and then it has been improved by increasing insidetemperature.In early minutes of cooling period, opposite to thewarm-up period, sensible heat exchange occurs fro