1、442 2008 ASHRAE ABSTRACTThe purpose of this work is to add to the understanding ofthe complex human body and its functions with the aid of thephysical laws of nature. Here, we reveal the influence that theenvironmental temperature has on a persons ability to dowork, which in turn affects the nations
2、 ability to producegoods and services to contribute to the advancement of thenations economy. The implementation of the Second Law ofThermodynamics to the human body predicts that the usefulwork per person in moderate, temperate climates is more thanthat in extreme hot or frigid climates. The availa
3、bility ofcomfortable environments for the labor force in temperateclimate can foster workers productivity to an optimum level.Therefore, countries consume a high amount of energy toproduce this optimum productive environment to increase thegrowth of services and products. An investigation of the cos
4、tof artificially producing a comfortable environment shows ahigher cost of cooling over heating. In this study first, we eval-uate the labor forces productivity of 169 countries that havedata available by measuring the total goods and services,which are produced per year through Gross Domestic Prod-
5、ucts per Capita (GDP) data. Secondly, a city from each countryis randomly selected to represent the average mean tempera-ture of these countries. The data shows that the predispositionsof the countries where the climatic conditions are extremely hotor frigid have poorer labor forces productivity tha
6、n those withmoderate, temperate climates. This finding add to our under-standing of human beings; the fact that their behaviors andperformances are affected by their environment; and how ulti-mately, our economic wellbeing is affected by physical factorssuch as the temperature.INTRODUCTIONThe study
7、of energy loss from the human body withrespect to the environment at equilibrium is needed to analyzea persons ability to do work under different environments.The objective of the work is to add to the understanding of thecomplex human body and its functions, with the help of thephysical laws of nat
8、ure. We will demonstrate that the physicalvariable that links the climate to a persons ability to do workis the environmental temperature, which in turn affects thenations ability to produce goods and services to contribute tothe economy.The thesis has been put forward that the second law ofthermody
9、namics, which interpolates the effects of heat losswithin the body at different environmental temperatures,predicts more useful work per person in moderate, temperateclimates than that in extreme, hot or frigid climates. Thestudy investigated the effect of environmental temperature onthe labor force
10、s productivity of goods and services withineach country by measuring the GDP per capita for 169 coun-tries where data is available. A city from each country hasbeen chosen randomly to represent the average mean temper-ature of the country to classify the countries into the hottest,the frigid and the
11、 temperate regions. The frequency oftemperate conditions most of the year in nature enhances theability to do work, which contributes to better productivity.On the other hand, an exceptionally hot or frigid climatereduces a persons ability to do work, which in turn affectshis productivity negatively
12、. Extended to the whole country,the countrys economy is negatively impacted by extremeclimactic conditions unless the country has the resources ofproducing these comfortable environments artificially in thework place.Prediction of More Useful Work from a Person in Moderate, Temperate Climate by Usin
13、g the Second Law of ThermodynamicsKau-Fui V. Wong, PhD, PE Ahmed AlhajajKau-Fui V. Wong is a professor and Ahmed Alhajaj is a graduate student at the Mechanical and Aerospace Engineering Department, Univer-sity of Miami, Coral Gables, FL.NY-08-0542008, American Society of Heating, Refrigerating and
14、Air-Conditioning Engineers, Inc. (www.ashrae.org). Published in ASHRAE Transactions, Volume 114, Part 1. For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAEs prior written permission.ASHRAE Transactions 443The
15、evidence of chronically poor economies because ofextreme climates has not been reached previously. We can gaina better understanding of this relationship by studying the ther-modynamic equilibrium of a person and his environmentaltemperatures, which augments our understanding about hisability to do
16、work. We discussed the potential of a personsability to do work as influenced by temperature conditions.RELATED WORKSThe study of economics does not only concern socialscientists and economists, but many physicists such as Formerand Shubik (2005), who are now doing research in a progres-sive field c
17、alled “econophysics”. This field contributes ininterpolating the differences and similarities in economies bylooking at different data with a different prospective of viewsto arrive at new equations that relate their data to some phys-ical variables.The physical effect of environmental temperature h
18、asbeen studied by social scientists, physicians and meteorolo-gists since the early 1900s. The climate is interpolated as animportant factor in deciding the history of civilization. Thefavorable climate of Greece most of the year was believed byHuntington (1945) to be the reason for their rise above
19、 theempires of Asia. In addition, the effect of climate was used byMarkham (1947) to predict the victory of the Second WorldWar depending on the climate of each side.The effects of temperature on diseases were introduced byphysicians such as Winslow (1949) and Mills (1942) studyingthe effects of env
20、ironmental temperature on human health.They introduced the effect of environmental temperature onthe animals ability to eat. The investigation, which was doneon mice at very high temperatures, showed that they did not eatthat much due to their inability to release all the heat loss; thissubsequently
21、 affected the health of the mice.The study of thermal comfort in the buildings is an impor-tant field to increase the comfort and minimize energyconsumption. Actually, the heat exchange from the person tothe room in the building is controlled by the first law of ther-modynamics and it can predict an
22、 uncomfortable feeling ofnon-equilibrium between gaining heat or losing heat to theroom via convection or sweating. The availability of work orexergy under steady state is used by Prek (2004) to increase theefficiency of air conditioning in the building. The study of thisequilibrium here is going fu
23、rther to provide evidence of theeffect of environmental temperatures on the productivity andthe economy of whole nations.SECOND LAW THEORY AS APPLIED TO CURRENT RESEARCHThe main objective of the present research is to introducethe thesis that the second law of thermodynamics predictsmore useful work
24、 per person in moderate, temperate climatesthan that in extreme, hot or frigid climates.In thermodynamics, a single human person may bemodeled as a heat engine. The metabolic rate is the rate of heatincoming into the heat engine of the human person at the coretemperature of 37C. This metabolic rate
25、is constant between20C and 37C Kleiber (1975). Above 37C and below 20C,the metabolic rate increases from this constant rate because thebody is under stress.From implementing the second law of thermodynamics,as outlined by Wong (2000), in the human person, we can seethat because of the metabolic rate
26、 in each human person, heathas to be rejected. The second law does not allow this entiremetabolic rate to be converted into useful rate of doing work.The difference between the metabolic rate M(TH) and the heatloss rate QLshown in Figure 1 gives the available rate of usefulwork per person, W.W = M(T
27、H) QL(1)We can now compare Equation (1) with Fangers (1972)comfort equation for the human person. His comfort equationpredicts that human comfort depends on the four physical vari-ables air temperature ta, air velocity va, mean radiant temper-ature and relative humidity pa.W = M H Ec Cres Eres(2)whe
28、reH = dry heat lossEc = evaporative heat exchange at the skin, when the person experiences a sensation of thermal neutralityCres= Respiratory convective heat exchangeEres= Respiratory evaporative heat exchangeAt optimum comfort conditions, Cresand Eresmay beassumed to be negligible. So this will lim
29、it our considerationsto optimum comfort conditions, relating to optimum workFigure 1 The heat engine representation of the humanperson.tr444 ASHRAE Transactionsoutput per person. With this limitation, Fangers equationreduces toW = M H Ec (3)Note that in this equation, Fanger treats M to be constant.
30、Following the works of Kleiber(1975) and Swift(1932), weuse the more accurate model that M is a function of the envi-ronmental temperature TH. Equation (3) is very similar to theequation proposed in the current research, Equation (1),except that Fangers M is not a function of environmentaltemperatur
31、e, but a function of human activity.Kleibers study introduced that the change of metabolicrate is needed to keep the homothermous animals underconstant temperature shows the effect of environmentaltemperature in changing the metabolic rate. Figure 2 showsthat the metabolic rate stays steady between
32、20C (68F) and37C (98.6F). However, the metabolic rate increases whenthe environmental temperature is hot (over 37C) or start to getcold (under 20C). Similar results of dividing the effect ofmetabolic rate through three zones had been found by R.W.Swift where he had investigated the effect of environ
33、mentaltemperature on his students while wearing normal clothes, asshown in Figure 3.Both these studies help us conclude that the metabolicrate is dependent principally on the environmental tempera-ture. The environmental effect is recognizable in three sepa-rate zones: A, B and C. The resulting equa
34、tions to calculateuseful work per person and the heat loss per person in each ofthe three climatic zones are being put forward in this currentresearch.Zone A TL 37C (98.6F)Zone A is the hottest zone. In this zone, the statisticalnorm of the environmental temperature most of the year fallsabove 37C.
35、The metabolic rate increases and the blood flowto the surface increases up to the evaporation heat loss (Ec).The useful work is reduced due to the high evaporative heatloss shown in Equation (4).W = M(TH) Ec (4)Equation (4) is similar to Equation (1) proposed in theresearch where the heat loss is so
36、lely released by evaporativeheat loss.Zone B 20C (68F) TL 37C (98.6F)Zone B is the temperate zone. In this zone, the statisticalnorm of the environmental temperature most of the year fallsbetween the critical temperature 20C and the core tempera-ture 37C. In this zone, the metabolic rate of the huma
37、n personis constant, which leads to less heat loss and more useful work.The evaporative and dry heat losses shown in Equation (5) arevery small compared to zone A or zone C.W = M H Ec (5)Equation (5) is similar to Equation (1) proposed in the researchwhere the heat losses are by evaporative and dry
38、heat loss.The second law equation of exergy (availability) can beused in this zone only due to the fact that the metabolic rate (M)is constant and the irreversibilities are removed because thebody is not under stress. While using the second law, it predictsmore exergy (availability) of useful work p
39、er person in coun-tries where the mean temperature during work hours (daytime) falls closer to the critical temperature (20C) than thecore temperature (37C) as shown in Equation (6).(6)whereTL= the environmental temperatureTh= the core temperature (37C)M = the metabolic rate (constant).Figure 2 Anim
40、al heat production versus environmentaltemperature, Kleiber (1975).Figure 3 Heat requirement and metabolic rate of a manversus environmental temperature, Swift (1932).WM1TLTH-=ASHRAE Transactions 445This mean temperature during work hours (day time) isused as the environmental temperature, TL. As TL
41、 TH, theratio TL/TH 1, hence the available work 0. As TL 20C,the ratio TL/TH the lower limit in this zone of 20/37, hencethe available work increases.Zone C TL29CNorwaycFarsund 0 9 12 3IcelandcDjuplvogur 2 10 0 0AustraliabOakwood 0 0 12 0LuxembourgcLarochette 1 8 3 0CanadacChilliwack 0 9 3 0SwedencU
42、llevi 3 7 2 0SwitzerlandcZurich 1 7 4 0IrelandcGalway 0 10 2 0BelgiumcBrussels 0 8 4 0United StatesbCollege Station 0 6 6 0JapanbFuija 0 0 12 0NetherlandscValkenburg 0 10 2 0FinlanddTurku 5 5 2 0DenmarkcSonderborg 0 9 3 0United KingdomcMelton 0 10 2 0FrancebMontelimar 0 7 5 0AustriacFeldkirch 3 6 3
43、0ItalybNaples 0 6 6 0New ZealandcBluff 0 12 0 0GermanycMulhouse 0 9 3 0SpainbRota 0 4 8 0Hong Kong,bChina (SAR) Hong Kong 0 0 12 0IsraelbHaifa 0 2 10 0GreecebPreveza 0 6 6 0SingaporebKampong Nior 0 0 12 0SloveniacLjubljana 3 5 4 0PortugalbSanta Maria 0 1 11 0Korea,bRepublic of Cheju 0 6 6 0CyprusbLa
44、rnaca 0 4 8 0BarbadosbSt. John 0 0 12 0Czech RepubliccLiberec 3 7 2 0MaltabKirkop 0 4 8 0Brunei DarussalambBander 0 0 12 0ArgentinabAndalgala 0 4 8 0HungarybPecs 1 6 5 0PolandcBielsko-Biala 3 6 3 0ChilebArica 0 0 12 0EstoniacPoldeotsa 4 5 3 0LithuaniacGarliava 4 5 3 0QataraDoha 0 0 7 5United Arab Em
45、iratesaAbu Dhabi 0 0 8 5SlovakiabBratislava 1 6 5 0BahrainaManama 0 0 7 5KuwaitaAl Funnayhil 0 2 5 5CroatiabDubrovnik 0 6 6 0UruguaybMercedes 0 5 7 0Costa RicabDesamparados 0 0 12 0LatviacLiepaja 3 7 2 0Saint Kitts and NevisbBasseterre 0 0 12 0BahamasbNassau 0 0 12 0SeychellesbAnsse Boileau 0 0 12 0
46、MexicobCancun 0 0 12 0TongabPea 0 0 12 0BulgariabPleven 1 6 5 0PanamabDavid 0 0 12 0Trinidad and TobagobCunupia 0 0 12 0aHottestbTemperatecColddFrigid448 ASHRAE TransactionsTable 2. The Number of Months for Which Each Citys Average Mean Temperature Lies Within the Characteristic Temperature Bounds o
47、f the ZonesMedium Development CountriesMedium Development Country CityNumber of MonthsT 0CC TC 14C14C 29CMacedonia,bTFYR Stip 0 7 5 3Antiqua and BarbudabCodrington 0 0 12 0MalaysiabButterworth 0 0 12 0Russian FederationdBarnaul 5 4 3 0BrazilbJuiz de For a 0 0 12 0RomaniabMedgidia 2 5 5 0MauritiusbMa
48、heboug 0 0 12 0GrenadabSaint Georges 0 0 12 0BelaruscKalinkavicy 4 5 3 0Bosnia and HerzegovinabStolac 0 6 6 0ColombiabCali 0 0 12 0DominicabRoseau 0 0 12 0OmanbDhuwwah 0 0 11 1AlbaniabGjinokaster 0 7 5 0ThailandbPan phran on 0 0 12 0Samoa (Western)bApia 0 0 12 0VenezuelabCoro 0 0 8 4Saint LuciabChoi
49、seul 0 0 12 0Saudia ArabiaaAl basar 0 3 4 5UkrainebDonetsk 3 4 5 0PerucCuzco 0 12 0 0KazakhstandAtbasar 5 4 3 0LebanonbBeitrut 0 2 12 0EcuadorbIbarra 0 0 12 0ArmeniacCyumri 4 5 3 0PhillippinesbBaler 0 0 12 0ChinabShanghai 0 5 7 0ParaguaybPilar 0 0 12 0TunisiabSfax 0 4 8 0JordanbAmman 0 3 9 0BelizebKendal 0 0 12 0FijibSuva 0 0 12 0Sri LankabKotte 0 0 12 0TurkeybAdana 0 4 8 0Dominican RepublicbAzua 0 0 12 0TurkmenistanbChardzhou 0 6 6 0JamaicabNegril 0 0 12 0Iran,bIslamic Republic of Deraz 0
