制冷專(zhuān)業(yè)畢業(yè)設(shè)計(jì)(家用空調(diào))(論文+DWG圖紙)

制冷專(zhuān)業(yè)畢業(yè)設(shè)計(jì)(家用空調(diào))(論文+DWG圖紙),制冷,專(zhuān)業(yè),畢業(yè)設(shè)計(jì),家用空調(diào),論文,dwg,圖紙 鄭州輕工業(yè)學(xué)院 本科畢業(yè)設(shè)計(jì)（論文） 英文翻譯 題 目 在汽車(chē)中熱化階段和 冷卻階段的熱舒適性 學(xué)生姓名 專(zhuān)業(yè)班級(jí) 學(xué) 號(hào) 院 （系） 指導(dǎo)教師(職稱(chēng)) 完成時(shí)間 18 在汽車(chē)中熱化階段和冷卻階段的熱舒適性 在汽車(chē)中熱化階段和冷卻階段的熱舒適性 O. Kaynakli . E. Pulat . M. Kilic 摘要: 大多數(shù)汽車(chē)有暖氣通風(fēng)和空調(diào)裝置來(lái)控制車(chē)輛內(nèi)部的熱環(huán)境。但是在炎熱或者寒冷的冬季里，從汽車(chē)啟動(dòng)到行駛穩(wěn)定很難達(dá)到并且保持熱舒適度，在這些過(guò)渡階段，人類(lèi)有體溫調(diào)節(jié)程序領(lǐng)悟并促使冷暖系統(tǒng)改進(jìn)和改良。這一項(xiàng)研究呈現(xiàn)出在汽車(chē)內(nèi)部環(huán)境和人類(lèi)身體之間的熱交換作用的模型。模型基于人類(lèi)身體的熱平衡等式.和定義出漢率和皮膚表面平均溫度的經(jīng)驗(yàn)公式相結(jié)合，這種模擬已被短暫的情況下使用運(yùn)行。汽車(chē)內(nèi)部熱化和冷卻過(guò)程對(duì)熱舒適度的影響已經(jīng)被研究。結(jié)果跟現(xiàn)在的測(cè)量和文獻(xiàn)資料中可獲得的實(shí)驗(yàn)數(shù)據(jù)相符合。它表明實(shí)驗(yàn)數(shù)據(jù)和模型的協(xié)議結(jié)合非常好。 符號(hào)目錄 A 表面區(qū)域,m2 熱傳導(dǎo)率，W 特性熱,J/(kg K) 織物層的外部半徑 CSIG 寒冷信號(hào) R 熱或蒸發(fā)阻力，(m2 K)/W 或者 (m2 KPa)/W 修正常數(shù) S 儲(chǔ)蓄熱，W 傳熱系數(shù),W / (m2 K) t 時(shí)間,s (除非在數(shù)分鐘內(nèi)指定) 片段系數(shù) 溫度， 空氣或織物層數(shù) 熱感覺(jué) 傳導(dǎo)的傳熱系數(shù),W/ (m K) 空氣流速，m/s 熱負(fù)荷, W / m2 皮膚濕度 身體塊,kg 濕氣比，kg H2O/kg dry air 每單位區(qū)域塊流程率；kg / (s m) 外部工作完成速率，W 熱量制造的新陳代謝率；W WSIG 溫暖信號(hào) nl 分層的數(shù)量 厚度，mm 水蒸氣壓力；KPa 希臘符號(hào) 皮膚層塊與身體總塊的比率 滲透效率 下標(biāo)數(shù)字 a 空氣 ex 呼氣 al 空氣層 f 織物 b 身體 int 外部衣物表面和固體的 界面（例如座位或靠背） bl 血液 max 最大值 cd 傳導(dǎo) n 中間的 cl 衣服 rex 呼吸 cr 核心 rd 輻射 cv 對(duì)流 s 飽和的 dif 散布 sk 皮膚 e 易受到對(duì)流和輻射的環(huán)境 sw 汗液 ev 蒸發(fā) t 總數(shù) 1介紹 一輛汽車(chē)的司機(jī)和乘客的舒適感部分取決于車(chē)輛內(nèi)部空氣的質(zhì)量和溫度，三個(gè)相關(guān)的系統(tǒng)被用于提供所需求的空氣溫度和質(zhì)量。這些是通風(fēng)系統(tǒng)，暖氣通風(fēng)和空調(diào)系統(tǒng)。一輛車(chē)的暖氣通風(fēng)和空調(diào)系統(tǒng)的作用是為它的乘坐者提供完全的熱舒適。因此，非常必要去了解人身體的熱量方面的情況，以便設(shè)計(jì)一個(gè)的效的HVAC系統(tǒng)。 為了估計(jì)熱舒適水平，環(huán)境熱量方面的準(zhǔn)確信息是必需的。環(huán)境熱量能概略地被汽車(chē)內(nèi)部的空氣溫度、速度和濕度表現(xiàn)。在交互作用中，熱量和傳質(zhì)一起發(fā)生。完成人類(lèi)舒適的模型包括能量平衡液體和材料熱力性能相等，熱量和傳質(zhì)特性，一輛汽車(chē)的乘客坐的車(chē)廂在冬季中被通過(guò)冷卻劑------空氣的熱交換器的循環(huán)熱引擎冷卻加熱以使車(chē)廂的空氣暖和。加熱系統(tǒng)被設(shè)計(jì)成與空氣流通系統(tǒng)一同操作，以便能提供所需的溫度。 隨著引擎大小的改進(jìn)變小，從燃料的經(jīng)濟(jì)方面和車(chē)輛加熱系統(tǒng)的可利用熱量相應(yīng)地減少方面考慮，從考慮市場(chǎng)情況出發(fā)為確保乘客的熱舒適感，甚至在極端的情況下，有一種發(fā)展更有效的系統(tǒng)的興趣為達(dá)到并保持乘客的熱舒適感是很困難的。一些輔助的加熱或冷卻裝置或許極大地減少了需要達(dá)到熱舒適的時(shí)間，但是這個(gè)裝置的能量需求是很大的。 在嚴(yán)熱的季節(jié)，空調(diào)被應(yīng)用。當(dāng)提起空調(diào)裝置時(shí)。腦海里第一個(gè)想法是冷卻和清爽的空氣。事實(shí)上汽車(chē)空調(diào)系統(tǒng)不僅冷卻空氣而且清潔、除溫使空氣流通以使乘客健康舒服，這些程序同加熱和通風(fēng)系統(tǒng)一起運(yùn)行。 人類(lèi)的熱舒適感早被認(rèn)為是先前的研究課題，有許多被證明和編成法典的可利用的數(shù)據(jù)[3]。在文獻(xiàn)中，大多數(shù)研究考慮熱量狀況幾乎一致完整地覆蓋乘客的整個(gè)身體。在乘客身體被很不均勻和短暫覆蓋的狀況下比較少的注意出現(xiàn)在指向在同一汽車(chē)內(nèi)的熱舒適。 Yigit[18]計(jì)算了每一個(gè)身體部分的熱損失和穿五件不同套裝時(shí)整個(gè)身體的熱損失。然而身體各個(gè)部位的熱損失沒(méi)有被考慮，衣物阻擴(kuò)抗對(duì)臺(tái)戲熱舒適的影響也沒(méi)有被估計(jì)。 Mccullough et al[13，14]出版了絕緣價(jià)值，典型的衣服套裝蒸發(fā)與熱力模型對(duì)比。這些參數(shù)也被用于測(cè)量使用熱力裝置加濕的部分織物。一個(gè)計(jì)算機(jī)模型被開(kāi)了出來(lái)用于估計(jì)熱傳遞中干燥和蒸發(fā)空氣的阻力。Olesen et al.[15]研究了五套具有相同全部熱力絕緣的不同衣服套裝，但是對(duì)16個(gè)靜止不動(dòng)的實(shí)驗(yàn)主題實(shí)驗(yàn)是知身體的上部分到下部分排列，他們的實(shí)驗(yàn)研究將會(huì)給測(cè)量衣服套裝的熱阻不均勻提供一個(gè)方法，并且檢查它是如何影響使當(dāng)?shù)責(zé)崃坎环€(wěn)定。 Tanebe et al.[16]，用一個(gè)模型調(diào)查了人體幾個(gè)部分有感覺(jué)的潛伏的熱損失。對(duì)于身體上每一個(gè)考慮過(guò)的部分，總的熱傳遞系數(shù)和熱阻力被出現(xiàn)。既使他們的研究是在封閉的環(huán)境中進(jìn)行，它沒(méi)有提供任何熱舒適的結(jié)果。Kaynakli et al.[11]報(bào)告一頇研究說(shuō)人類(lèi)身體被分成16個(gè)部分，在每一個(gè)16個(gè)身體部位和環(huán)境之間熱交互的計(jì)算機(jī)模型被開(kāi)發(fā)出來(lái)。隨著模型的使用，坐著和站著時(shí)身體的各個(gè)部分和整個(gè)身體的皮膚濕潤(rùn)情況和潛在（蒸汗蒸發(fā)，擴(kuò)散）和有感覺(jué)的（傳導(dǎo)、對(duì)流、輻射）的熱量損失被計(jì)算出來(lái)。Kaynakli et al. [12]呈現(xiàn)人體和環(huán)境間和質(zhì)量傳遞的數(shù)學(xué)模型。在他們的研究中，人們?cè)诓蛔兊那闆r下獲得滿(mǎn)足感所需的環(huán)境的個(gè)人狀況和總計(jì)的有感覺(jué)的和潛在的熱損失，皮膚溫度、出漢、預(yù)測(cè)的平均贊成率（PMV）和預(yù)測(cè)的不滿(mǎn)意百分比（PPD）的價(jià)值經(jīng)由模型被計(jì)算出來(lái) 。 Chakroun和Al-Fahed[7]研究了一輛在科威特夏季數(shù)個(gè)月內(nèi)停在太陽(yáng)下的一輛汽車(chē)的溫度變化和熱舒適性。他們也認(rèn)為在汽車(chē)內(nèi)部用不同的內(nèi)部材料混合物對(duì)溫度有影響。Burch et al.[4]報(bào)告了在嚴(yán)寒冬季升溫時(shí)期的駕駛狀況下的一系列關(guān)于乘客熱舒適性的試驗(yàn)結(jié)果。他們發(fā)現(xiàn)安裝在座位和靠背上的小功率電力加熱設(shè)備極大地減少升溫時(shí)間可以綜合通過(guò)在空氣管道中安裝電加熱器實(shí)現(xiàn)，雖然與這種方法有關(guān)的能量需求是很大的，除了他們的實(shí)驗(yàn)研究之后。他們將關(guān)于這個(gè)課題的一項(xiàng)分析研究發(fā)表在Burch et al.[5]。 汽車(chē)啟動(dòng)時(shí)加熱和降溫期間需要一些時(shí)間達(dá)到穩(wěn)定的狀況。在這些時(shí)期，乘車(chē)者身體熱量分布十分不均。乘客感覺(jué)局部寒冷歸究于與一個(gè)最初的涼座位或于車(chē)輪接觸與環(huán)境不均勻的輻射熱傳遞，局部太陽(yáng)照射和空氣調(diào)速器的位置，儀表板控制的設(shè)定所決定的不均勻的空氣速率有關(guān)。因此為了達(dá)到保持汽車(chē)內(nèi)乘客的熱舒適性的技術(shù)發(fā)展中產(chǎn)生了很大興趣。 這項(xiàng)研究呈現(xiàn)一個(gè)人類(lèi)與汽車(chē)內(nèi)環(huán)境之間熱交互的模型。因此部分分析認(rèn)為局部不舒服是由在一個(gè)相對(duì)狹小空間內(nèi)。衣服隔熱不均勻造成的。比如汽車(chē)車(chē)廂內(nèi)。現(xiàn)在的模型是基于被分成16部分的人體的熱力平衡相等結(jié)合Gagge et al.’s[10]和Olesen et al.’s[15]的方法，所有身體部分被看作是二同心圓筒，需要背后數(shù)據(jù)比如身體部分的表面積，它們質(zhì)量從現(xiàn)有文獻(xiàn)中提取，這樣，除了gagge et al.’s[10] 的模型，盡量通過(guò)計(jì)算身體各個(gè)部分的熱交換和皮膚溫度，出漢率來(lái)定義局部不舒適性。在短暫的情況下模擬被運(yùn)行應(yīng)用。汽車(chē)內(nèi)部加熱和降溫過(guò)程對(duì)舒適性的影響已經(jīng)被證明。實(shí)驗(yàn)也指導(dǎo)了冷卻周期，直到汽車(chē)達(dá)到熱舒適性，溫度和溫度才發(fā)生改變。司機(jī)和乘客被這些變化極達(dá)地影響，為證明現(xiàn)在的模型，模擬結(jié)果和實(shí)驗(yàn)做了比較。 2 數(shù)字模型 從乘客上面流過(guò)的環(huán)境空氣的速度從小空間熱舒適性觀點(diǎn)來(lái)說(shuō)非常重要，因?yàn)樗泻艽蟮募訜岷徒禍啬芰Γ缭谄?chē)車(chē)廂內(nèi)，在司機(jī)和乘客上方流動(dòng)的空氣進(jìn)入衣服開(kāi)衩口對(duì)于任何乘客身體沒(méi)有相同作用。雖然對(duì)于典型戶(hù)內(nèi)狀況取代平均速度是好的近似值，但以汽車(chē)內(nèi)部看來(lái)結(jié)果會(huì)產(chǎn)生很大的錯(cuò)誤。坐著的乘客身體上方局部空氣流速被Burch et al.[5] （表1）經(jīng)實(shí)驗(yàn)列出。在這項(xiàng)研究中，測(cè)定乘客身體各部分熱損失的因素基于這些速度值。 在這項(xiàng)研究中用的模型是基于Olesen et al.[15]中描述的方法。在這項(xiàng)研究中為了證明冬天和夏天條件下，環(huán)境熱量對(duì)于乘客坐者尤其是司機(jī)詳細(xì)的影響，考慮身體上衣服和當(dāng)?shù)乜諝饬魉俚挠绊懭梭w被分成16部分。在表2中，表面積和他們身體表面積的各小部分都已給出。 用身體各部分儲(chǔ)存的能量來(lái)計(jì)算當(dāng)時(shí)，溫度變化許多這些身體部分大量的身體部分和他們身體的保各個(gè)小部分見(jiàn)表3。 將人體視作一個(gè)整體，從熱舒適性觀點(diǎn)看平均皮膚溫度是個(gè)不主意，但是四肢例如：手、腳和臉或者裸露和身體部分的溫度可能增加或減少不必要的數(shù)值。通過(guò)使用發(fā)展了的模型，影響熱舒適性的每一個(gè)身體部分的有感覺(jué)的和潛能在熱損失的參數(shù)變化的時(shí)間率，皮膚溫度和皮膚出汗率可能被研究。 2．1人類(lèi)身體的熱力和生理學(xué)模型 兩包廂間過(guò)渡性熱量平衡模型被Gagge et al.[10]發(fā)明，將身體描述成兩個(gè)同心圓筒，里面的圓筒代表身體核心（骨骼、肌肉、內(nèi)臟）另外一個(gè)圓筒代表皮膚層。這個(gè)模型考慮到核心和皮膚部分即時(shí)的熱量?jī)?chǔ)存，假定這些部分的溫度隨時(shí)間變化。這個(gè)熱力模型用一對(duì)熱力平衡等式來(lái)描述，其中一個(gè)適用于任何部分[3]： 式子中，代表熱力產(chǎn)生的新陳代謝率，代表機(jī)械工作的熟練程度，呼吸的熱損失率，熱量從體內(nèi)到皮膚的傳輸率，, , 從皮膚層到環(huán)境分別以傳導(dǎo)對(duì)流和輻射方式的熱損失率，和表示在體內(nèi)和皮膚層儲(chǔ)存的能量在為些部分引起的瞬時(shí)溫度改變。這些效果可用下列等式表示： 代表身體部分質(zhì)量，代表身體特有熱量。和出現(xiàn)在等式2中代表對(duì)流和輻射和熱傳遞，可用下列關(guān)系計(jì)算： 式中，是暴露到環(huán)境中的身體部分的外表面積總面積除去與座位接觸的面積，靠背面積等等）代表穿衣服的身體部分與裸露的身體部分表面區(qū)域的比率包括平均輻射和周?chē)諝鉁囟热缦滤荆? 熱輻射傳熱系數(shù)取值4.7n/(m2.k)是因?yàn)樗糜趦?nèi)部狀況足夠精確[3]身體各部分的對(duì)流熱傳遞數(shù)在de Dear et al.[8]中取值。由于皮膚總的潛熱損失來(lái)自蒸發(fā), 表示為： 式中, 是蒸發(fā)比率, 是皮膚溫度的飽和水蒸汽分壓力, 是環(huán)境空氣的水蒸汽分壓力, 是衣物的浸透高效率,LR是蒸發(fā)熱傳遞與對(duì)對(duì)流熱傳遞系數(shù)的比的路易斯系數(shù).McCullough et al.[14]已經(jīng)發(fā)現(xiàn)通常室內(nèi)衣物浸透系數(shù)平均值=0.34 總皮膚的潮濕度(),包括常規(guī)出汗引起的和通過(guò)皮膚擴(kuò)散的濕度,均由下列式子給出. 最大的蒸發(fā)潛能,當(dāng)皮膚表面完全浸濕(=1)時(shí), 出現(xiàn). 在一輛汽車(chē)中身體表面的重要部分(15—20%)是由座位,靠背和方向盤(pán)接觸的,這部分不是認(rèn)為以對(duì)流、輻射方式散失熱量.由于皮膚熱傳導(dǎo)的熱損失由下式給出： 在兩個(gè)節(jié)點(diǎn)模型中,身體中心和皮膚間的熱交換由通過(guò)直接接觸和皮膚血液流動(dòng)發(fā)生的。身體的平均熱電導(dǎo)常量被假定為=5.28W/(m2 k)從身體中心到皮膚的熱流動(dòng)如下式： 血液的特定熱，是4.187J/(kg k)呼吸熱損失大約是總熱損的10%,呼吸熱損失大約是總熱損的10%。由于呼吸的熱損失如下式： 式中是吸入空氣的流動(dòng)率, 和分別是出氣溫度和周?chē)諝鉁囟取：头謩e是呼氣和周?chē)諝獾臐駳獗?蒸發(fā)的熱量是2.43×106J/kg. 皮膚塊與總身體塊的比率()被當(dāng)作身體核心的下述功能與皮膚中血液流動(dòng)的比的模型: 每單位皮膚面積內(nèi)核心到皮膚的血液流動(dòng)被表示成: 每單位皮膚區(qū)域的出汗率被估計(jì)為: 人體平均溫度能通過(guò)皮膚到核心的重要平均溫度預(yù)測(cè): 身體中間溫度能用同樣方法通過(guò)皮膚到核心的中間溫度計(jì)算. 身體被分成16個(gè)統(tǒng)一穿衣物的部分.每個(gè)部分的總熱阻和總蒸發(fā)熱阻如下各項(xiàng). 假定通過(guò)空氣層和衣物層的熱傳遞是以傳導(dǎo)和輻射方式發(fā)現(xiàn),在這種情況下空氣層的熱阻如下式: 式中,Xa是空氣層厚度, Hrd和k的數(shù)值是Hrd=4.9(㎡k)和k=0.024W/(mk)[14]蒸發(fā)熱阻也能寫(xiě)成相似的等式.空氣層的蒸發(fā)熱阻如下式: 式中a和b是常數(shù).a和b的數(shù)值分別是0.0334(㎡kpa)/W和15mm[14]裸露在環(huán)境中的外表面處理的有一點(diǎn)不同.外層的熱阻為: 外層的蒸發(fā)熱阻通過(guò)對(duì)流的熱傳遞系數(shù)和路易斯關(guān)系決定: 2.2 熱感覺(jué)的預(yù)測(cè) 上述等式描述了人體環(huán)境和溫度調(diào)節(jié)裝置間的熱交換.身體E熱能量熱負(fù)荷的組合,影響在身體與環(huán)境間熱量交換中的人熱舒適性.如果身體的熱負(fù)荷(L)幾乎是零,中間狀況或熱舒適性就達(dá)到了.運(yùn)動(dòng).衣服和四個(gè)環(huán)境系數(shù)(氣溫,平均發(fā)光溫度,空氣流速和濕度)的組合都影響熱舒適性.應(yīng)用最廣泛的熱舒適參數(shù)是熱感覺(jué)(TS),數(shù)值在式27中給出 式中,Ab是身體的總表面積,表4 給出了TS的比值. 2.3 假定和起始狀況 裸露的身體表面積取為Ab=1.75/㎡,體重是80千克,核心和皮膚的初始溫度值分別取為36.8℃和33.7℃ 夏季衣物隔熱率,冬季衣物隔熱率,夏季衣物的衣服面積因素,冬季衣物的衣服面積因數(shù)和活動(dòng)的新陳代謝率分別取為:0.5clo,1.5clo,fcl=1.1,fa=1.15和75W/㎡.[5,6] 身體上的局部空氣速度在表1中給出,加熱和冷卻過(guò)程的平均空氣溫度(Ta)見(jiàn)圖1和圖2,加熱階段相關(guān)的溫度取0.35[5],冷卻階段見(jiàn)圖3,平均輻射溫度在加熱階段取為在冷卻階段取為 在加熱階段與身體(Tint)接觸的物體的表面溫度(t從起動(dòng)開(kāi)始的以分鐘計(jì)的時(shí)間)如下式 座位: 與座位接觸的穿衣物的身體面積:0.07㎡. 靠背: 與靠背接觸的穿衣物的身體面積:0.07㎡. 方向盤(pán): 與方向盤(pán)接觸的穿衣物的身體面積:0.01㎡. 在冷卻階段,發(fā)現(xiàn)身體有接觸物體的表面溫度(Tint)與運(yùn)行實(shí)驗(yàn)（t是以分鐘計(jì)）的結(jié)果一樣（表5）。 3 結(jié)果與討論 為了證明加熱和冷卻過(guò)程對(duì)汽車(chē)內(nèi)部狀況的影響，數(shù)學(xué)模型部分中的等式運(yùn)用Delphi6系統(tǒng)語(yǔ)言來(lái)指導(dǎo)計(jì)算機(jī)媒體。在加熱階段，需要靠背和方向盤(pán)表面溫度都取自Burch et al.[5]，在他們的實(shí)驗(yàn)研究中，內(nèi)部空氣已經(jīng)被從-20℃加熱到20℃，如圖1所示。 冷卻過(guò)程所需要的實(shí)驗(yàn)數(shù)據(jù)在1991年裝有一個(gè)2000-cc引擎的豐田汽車(chē)被測(cè)量。汽車(chē)停在日光下，觀察到車(chē)內(nèi)氣溫上升到64℃，周?chē)h(huán)境溫度大的是30℃。稍后，標(biāo)準(zhǔn)的冷卻程序隨空調(diào)器的啟動(dòng)而開(kāi)啟。在這個(gè)過(guò)程中，車(chē)內(nèi)溫度，相關(guān)的溫度，座位，靠背和方向盤(pán)表面溫度被測(cè)量。測(cè)量的參數(shù)見(jiàn)圖2和圖3。因?yàn)樵谄?chē)內(nèi)溫度升到64℃時(shí)相關(guān)的濕度從50﹪減少到11﹪，所以在冷卻階段相關(guān)濕度從11﹪開(kāi)始。 在升溫過(guò)程中從身體到環(huán)境的熱損失在圖4中相比較地給出。因?yàn)锽urch et at.[5]的模型和現(xiàn)在的模型存在一些原則上不同（例如：在Burch的模型中身體被分成4個(gè)部分，但在我們的模型中身體被分成16個(gè)部分），故一些差別在開(kāi)始階段出現(xiàn)。除去這些相對(duì)小的時(shí)間間隔，結(jié)果間達(dá)成的一致也在可接受的范圍內(nèi)。由于與物體表面接觸的身體各部分的面積小于其它身體表面積，故座位、靠背和方向盤(pán)的傳導(dǎo)熱損失與總的對(duì)流和輻射熱損失相比相當(dāng)?shù)汀Ｔ谏郎剡^(guò)程的開(kāi)始階段，因?yàn)槠?chē)內(nèi)溫度和內(nèi)部表面溫度相當(dāng)?shù)?，傳?dǎo)、對(duì)流和輻射的熱損失很高。甚至這些總的熱損失比熱力過(guò)程中的新陳代謝高。因?yàn)檫@個(gè)原因，身體核心和皮膚溫度有一點(diǎn)減小。但是皮膚溫度的減小要比核心溫度減小的多。顯然這些熱損失的快速減小歸究與汽車(chē)內(nèi)溫度的升高。在這個(gè)過(guò)程中，身體試圖保持最小限度的呼吸和蒸發(fā)熱損失以便平衡熱損失。 升溫階段相對(duì)比的變化的Ts值見(jiàn)圖5，通過(guò)圖5的驗(yàn)證，與Burch et at.[5]有一個(gè)好的相吻合處。 這些計(jì)算在和分析研究中運(yùn)行。在他們的實(shí)驗(yàn)中，Ts的數(shù)值由參考數(shù)據(jù)獲得，平均熱舒適性和參考數(shù)據(jù)的標(biāo)準(zhǔn)偏差通過(guò)時(shí)間計(jì)算?，F(xiàn)在研究計(jì)算結(jié)果在Ts±16范圍內(nèi)，的值取0.62。最初，從身體到環(huán)境的時(shí)間熱力損失由于汽車(chē)內(nèi)的低溫度緣故一直很高。因此，由于內(nèi)部溫度和外表面溫度升高，熱舒適性得到改善。 指出汽車(chē)車(chē)廂升溫階段環(huán)境狀況對(duì)人舒適的影響的一個(gè)參數(shù)是身體表面平均溫度和它隨時(shí)間的變化見(jiàn)圖6。在最初幾分鐘內(nèi)，由于車(chē)內(nèi)和物體內(nèi)部都很低的溫度，平均皮膚溫度立即下降。隨著車(chē)內(nèi)溫度隨時(shí)間而升高，在它的值降低到一個(gè)最小值32℃后平均皮膚溫度開(kāi)始升高。雖然平均表面溫度對(duì)人類(lèi)舒適狀況是一個(gè)好的信息，但也必須注意人體的局部不識(shí)。和固體表面接觸的身體背部、大腳和手的溫度在圖7中給出。內(nèi)部溫度對(duì)背部背部和腳的溫度影響不大，故它們的變化不重要。但是手面的溫度減小到17.5℃可以被估計(jì)為一個(gè)相當(dāng)?shù)偷臏囟?。在文獻(xiàn)中，提到當(dāng)手面溫度達(dá)到20℃時(shí)引起認(rèn)為不舒服的寒冷，達(dá)到15℃就極其寒冷[3]。 在冷卻過(guò)程中身體上的熱傳遞見(jiàn)圖8。由于在開(kāi)始車(chē)內(nèi)溫度和表面內(nèi)部溫度很高，有感覺(jué)的熱流動(dòng)（傳導(dǎo)、對(duì)流、輻射）從環(huán)境到人體發(fā)生。這種情況導(dǎo)致從身體內(nèi)部到皮膚溫度的升高。為繼續(xù)維持身體重要功能和另外確保舒適的狀況，從環(huán)境對(duì)身體的熱量和熱力過(guò)程的新陳代謝熱量必須被排放到環(huán)境中。因此，身體增加了出汗的次數(shù)，很快身體的很大部分被汗覆蓋。這樣，蒸發(fā)熱損失的增加見(jiàn)圖8。然而呼吸熱損失不受環(huán)境狀況的影響，它保持在大約10W。 Chakroun和 Al-Fashed′s[7]的研究中，冷卻階段的熱舒適性的變化分別在圖9中給出。在Chakroun和 Al-Fashed′s[7]的書(shū)中，詳細(xì)的環(huán)境狀況沒(méi)有給出，所以我們的模型無(wú)法直接應(yīng)用于他們的測(cè)量狀況。因此，這一個(gè)圖只是一個(gè)性質(zhì)上的比較。在他們的研究中，可以肯定停在太陽(yáng)下的汽車(chē)內(nèi)部溫度達(dá)到大約65℃。然后，冷卻程序通過(guò)操作A/C開(kāi)關(guān)研究調(diào)查。但是在相當(dāng)熱的氣候中進(jìn)行而環(huán)境溫度是45℃。然而在我們的實(shí)驗(yàn)中它是30℃。太陽(yáng)的輻射也比我們的情景下強(qiáng)。由于這個(gè)原因，汽車(chē)內(nèi)描述的溫度是不同的，所決定的Ts值也不一樣。在最早的幾分鐘內(nèi)，由于車(chē)內(nèi)高溫，熱量通過(guò)傳導(dǎo)，對(duì)流和輻射從環(huán)境傳到人體。因此，由于身體有一個(gè)明顯的熱負(fù)荷，Ts有一個(gè)很高的初始值。然后，熱負(fù)荷隨車(chē)內(nèi)溫度減小而減小，表面溫度和舒適狀況得到改善。 冷卻過(guò)程中身體、腳和手面平均溫度的變動(dòng)見(jiàn)圖10。但是，直接與空氣接觸的手的溫度的升高比其它部分大。隨著車(chē)內(nèi)冷卻時(shí)間變化，這個(gè)溫度升高度下降。手部最易受到環(huán)境狀況的影響，所以溫度的明顯減小呈現(xiàn)在手上。相似的情形對(duì)頭部來(lái)說(shuō)也很有效。既然鞋子是重要的隔熱元素，腳沒(méi)從內(nèi)部溫度變化受到影響。由于這一原因，在冷卻過(guò)程最后最高的溫度出現(xiàn)在腳部。身體的平均表面溫度在手和腳的溫度間改變。 改變舒適感的一個(gè)重要參數(shù)是皮膚濕度，它隨著時(shí)間的變化見(jiàn)圖11。在冷卻過(guò)程的初始階段，由于車(chē)內(nèi)溫度高，出汗率增加，以便增加身體的熱損失。因此皮膚的濕度增加。由于鞋子緣故，最快的增加發(fā)生在腳部。由于頭部沒(méi)有衣物阻止出汗的蒸發(fā)，手臂不與方向盤(pán)接觸，皮膚濕度在這些身體部分中最低，然而平均身體表面濕度在頭部和腳部濕度中間升高到最大值0.6。 4 結(jié)論 在這項(xiàng)研究中，介紹了內(nèi)部環(huán)境狀況對(duì)人類(lèi)生理學(xué)和加熱和冷卻過(guò)程對(duì)舒適性的影響。表示體溫控制裝置的基本熱交換等式和經(jīng)驗(yàn)關(guān)系被用于人體與環(huán)境間的熱質(zhì)傳遞。在這些過(guò)程中，考慮到車(chē)內(nèi)溫度和相關(guān)濕度和與身體接觸的物體表面的溫度，熱傳遞的變化，身體部分表面溫度和濕度和Ts數(shù)值都給了出來(lái)。 在升溫階段的最初幾分鐘，由于車(chē)內(nèi)和表面的低溫，從身體到環(huán)境的熱損失很大。在這個(gè)時(shí)期，蒸發(fā)熱損失通過(guò)體溫調(diào)節(jié)裝置保持在最小值。身體的平均皮膚溫度降到32℃，與方向盤(pán)接觸的手溫也降到一個(gè)很低的值17.5℃。由于從身體到環(huán)境的熱損失變得很重要，Ts值從-4.5開(kāi)始，然后隨內(nèi)部溫度升高，它開(kāi)始得到改善。 在冷卻階段的最初幾分鐘，和升溫階段相反，由于車(chē)內(nèi)和表面高溫，感覺(jué)熱交換從環(huán)境到身體間發(fā)生，由于這個(gè)原因，Ts值從一個(gè)相當(dāng)高的值8開(kāi)始，然后隨內(nèi)部溫度升高而下降。為了平衡身體與環(huán)境間的熱交換，出汗過(guò)程增加，所以潛在熱損失增加?？紤]到升溫和冷卻階段的呼吸熱損失都不受環(huán)境狀況的影響，隨著出汗過(guò)程增加，身體皮膚濕度增加，由于衣服熱絕緣度高，身體表面的皮膚濕度很高，相反，裸露的身體表面（例如頭和手）很低。同理，這些裸露的表面也是受環(huán)境狀況影響最快的部分。 除此之外，也提到了只有一名司機(jī)在車(chē)內(nèi)的停著的汽車(chē)的測(cè)量結(jié)果。汽車(chē)內(nèi)無(wú)人或汽車(chē)內(nèi)有乘客都可能影響測(cè)量結(jié)果。 參考文獻(xiàn) [1] Althouse A (1979) Modern refrigerations and air conditioning,The Goodheart Willcox Company, USA [2] Ar?c? O¨ , Yang SL, Huang CC, Oker E (1996) A numerical simulation model for automobile passenger compartment climate control and evaluation. In: International energy and environment symposium, Turkey 29–31 July, pp 1081–1087 [3] ASHRAE (1993) ASHRAE handbook—fundamentals, chapter 1. Atlanta: American society of heating, refrigeration and airconditioning engineers, p 34 [4] Burch SD, Pearson JT, Ramadhyani S (1991) Experimental study of passenger thermal comfort in an automobile under severe winter conditioning. ASHRAE Trans 97: 239–246 [5] Burch SD, Ramadhyani S, Pearson JT (1991) Analysis of passenger thermal comfort in an automobile under severe winter conditioning. ASHRAE Trans 97: 247–257 [6] Butera FM (1998) Chapter 3—Principles of thermal comfort. Renewable Sustainable Energy Rev 2: 39–66 [7] Chakroun C, Al-Fahed S (1997) Thermal comfort analysis inside a car. Int J Energy Res 21: 327–340 [8] de Dear RJ, Arens E, Hui Z, Ogura M (1997) Convective and radiative heat transfer coefficients for individual human body segments. Int J Biometeorol 40: 141–156 [9] Fanger PO (2001) Human requirements in future air-conditioned environments. Int J Refrigeration 24: 148–153 [10] Gagge AP, Stolwijk JAJ, Nishi Y (1971) An effective temperature scale based on a simple model of human physiological response. ASHRAE Trans 77(1): 247–262 [11] Kaynakli O, Unver U, Kilic M (2003) Evaluating thermal environments for sitting and standing posture. Int Commun Heat Mass Transfer 30(8): 1179–1188 [12] Kaynakli O, Unver U, Kilic M (2003) Calculation of thermal comfort zones with the ambient parameters. IEEES-1 the first international exergy, energy and environment symposium,Izmir, Turkey, July 13–17, pp 769–773 [13] McCullough EA, Jones BW, Huck J (1985) A comprehensive data base for estimating clothing insulation. ASHRAE Trans 91(2): 29–47 [14] McCullough EA, Jones BW, Tamura T (1989) A data base for determining the evaporative resistance of clothing. ASHRAE Trans 95(2): 316–328 [15] Olesen BW, Hasebe Y, de Dear RJ (1988) Clothing insulation asymmetry and thermal comfort. ASHRAE Trans 94(1): 32–51 [16] Tanebe S, Arens EA, Bauman FS, Zang H, Madsen TL (1994) Evaluating thermal environments by using a thermal manikin with controlled skin surface temperature. ASHRAE Trans 100(1): 39–48 [17] Winter DA (1979) Biomechanics of human movement. Wiley, Toronto [18] Yigit A (1998) The computer-based human thermal model. Int Commum Heat Mass Transfer 25(7): 969–977 20 ORIGINAL O. Kaynakli ? E. Pulat ? M. Kilic Thermal comfort during heating and cooling periods in an automobile Received: 9 September 2003/Published online: 17 September 2004 C211 Springer-Verlag 2004 Abstract Most vehicles have a heating, ventilation and air conditioning (HVAC) device to control the thermal environments of interior of the vehicle. But, under hot summer season or cold winter conditions, it is di?cult to achieve and maintain thermal comfort in an automobile from the start up to the steady-state conditions. During these transition periods, an understanding of human thermoregulatory processes facilitates the design and development of improved heating and cooling systems. This study presents a model of thermal interactions between a human body and the interior environment of an automobile. The model is based on the heat balance equation for human body, combined with empirical equations defining the sweat rate and mean skin tem- perature. Simulation has been performed by the use of transient conditions. The e?ects of both heating and cooling processes on the thermal comfort inside the automobile are investigated. Results are compared with the present measurements and available experimental data in the literature. It is shown that the agreement between the experimental data and the model is very good. List of symbols A surface area, m 2 c p specific heat, J/(kg K) CSIG cold signal f correction factor h heat transfer coefficient, W/(m 2 K) i segment number j air or fabric layers number k conductiveheattransfercoefficient,W/(m K) L heat load, W/m 2 m body mass, kg _m mass flow rate from per unit area, kg/(s m 2 ) M metabolic heat production rate, W nl number of layers covering segment p water vapor pressure, kPa Q heat transfer rate, W r outer radius of fabric layer R thermal or evaporative resistance, (m 2 K)/W or (m 2 kPa)/W S heat storage, W t time, s (unless specified in minutes) T temperature,C176C TS thermal sensation V air velocity, m/s w skin wettedness W humidity ratio, kgH 2 O/kg dry air _W external work rate accomplished, W WSIG warm signal x thickness, mm Greek symbols a ratio of skin layer mass to total body mass g permeation efficiency Subscripts a air al air layer b body bl blood cd conduction cl clothing cr core cv convection dif diffusion e exposed to convective and radiant environment ev evaporation O. Kaynakli ? E. Pulat ? M. Kilic (sk eiT C0C1 e1T S sk eiT?Q cr;sk eiTC0 Q cd eiTtQ cv eiTtQ rd eiTtQ ev eiTeT e2T where, M rate of metabolic heat production, 7pt _W rate of mechanical work accomplished, Q res total rate of respiratory heat loss, Q cr,sk rate of heat transport from core to skin, Q cn ,Q cv ,Q rd rate of heat loss from skin to environment by conduction, convection and radiation respectively. S cr and S sk that denotes stored energies in core and skin layer causes instantaneous temperature changes in these compartments. These e?ects are ex- pressed with following equations: dT cr eiT dt ? S cr eiT e1C0 aT meiTc p;b C0C1 e3T dT sk eiT dt ? S sk eiT ameiTc p;b C0C1 e4T where m is the body segment mass, c p,b is the specific heat of the body. Q cv and Q rd terms in Eq. 2 are the heat transfers with convection and radiation and can be cal- culated with following relation: eQ cv tQ rd TeiT? T sk eiTC0T o eiTeTA e eiT R cl eiTt 1=eh cv eiTth rd T f cl eiT?C138 e5T where, A e is the surface area of the body segments exposed to the environment (total area minus the area in contact with seat, back support, etc.), f cl is the ratio of the surface areas of the clothed body and the nude body. Operative temperature value (T o ) that includes average radiation and ambient air temperature is given as follows: T o eiT? h rd C22 T rd th cv eiTT a h rd th cv eiT e6T For radiative heat transfer coe?cient the value of 4.7 W/(m 2 K) is used since it is su?ciently accurate for internal conditions [3] and convective heat transfer coe?cient values of each segment of the body are taken Table 2 Surface areas of the body segments [15] Body segments Segment number Surface area [m 2 ] Fraction of total body surface area [%] Left foot 1 0.062 3.5 Right foot 2 0.062 3.5 Left fibula 3 0.140 8.0 Right fibula 4 0.140 8.0 Left thigh 5 0.160 9.1 Right thigh 6 0.160 9.1 Pelvis 7 0.080 4.6 Head 8 0.180 10.4 Left hand 9 0.050 2.9 Right hand 10 0.050 2.9 Left forearm 11 0.062 3.5 Right forearm 12 0.062 3.5 Left upperarm 13 0.077 4.4 Right upperarm 14 0.077 4.4 Chest 15 0.185 10.6 Back 16 0.204 11.7 The whole body 1.751 100.0 Table 3 Mass of the body segments [17] Body segments Segment number Mass (kg) Fraction of total body mass (%) Foot 1–2 1.16 1.45 Fibula 3–4 3.72 4.65 Thigh 5–6 8.00 10.00 Pelvis 7 6.78 8.48 Head 8 6.48 8.10 Hand 9–10 0.48 0.60 Forearm 11–12 1.28 1.60 Upperarm 13–14 2.24 2.80 Trunk 15–16 32.98 41.22 The whole body 80.00 100.00 452 as described in de Dear et al. [8]. The total latent heat loss from the skin due to evaporation, Q ev , is given by Q ev eiT? weiT p sk;s eiTC0p a C0C1 AeiT R cl eiT=g cl LReTt1=h cv eiT f cl eiT LReT e7T where, w is the wettedness ratio, p sk,s is the saturated water vapor partial pressure at the skin temperature and p a is the water vapor partial pressure in the ambient air, g cl is permeation e?ciency of the clothing and LR is the Lewis Relation which is the ratio of the evaporative heat transfer coe?cient to the convective heat transfer coe?cient. McCullough et al. [14] have been found an average value of g cl =0.34 for common indoor clothing. The total skin wettedness (w), includes wettedness due to regulatory sweating (w sw ) and to di?usion through to skin (w dif ) is given by w sw eiT? h fg _m sw eiT Q ev;max eiT e8T w dif eiT?0:06 1C0w sw eiTeT e9T weiT?w sw eiTtw dif eiTe10T Maximum evaporation potential, Q ev,max occurs when the skin surface is completely wetted (w=1). In an automobile, a significant portion (15–20%) of the body surface area is in contact with a seat, back support and steering wheel [5]. This portion does not lose heat by convection and radiation. The heat loss from the skin due to conduction is given by Q cd eiT? T sk eiTC0T int eT R cl eiT A cd eiTe11T In the two-node model, heat exchange between the core and the skin occurs by direct contact and through the skin blood flow. A constant average thermal conductance, K cr,sk =5.28 W/(m 2 K) is as- sumed over the body. The heat flow from core to skin is as follows: Q cr;sk eiT? K cr;sk tc p;bl _m bl C0C1 T cr eiTC0T sk eiTeTAeiTe12T The specific heat of the blood, c p,bl is 4,187 J/(kg K). Respiratory heat loss is approximately 10% of total heat loss [9]. The heat loss due to respiration is given by Q res ? _m res c p;a eT ex C0T a Tth fg eW ex C0W a T C2C3 A b e13T where _m res is the mass flow rate of air inhaled, T ex and T a are the exhaled air and the ambient air temperatures, respectively. W ex and W a are the exhaled air and the ambient air humidity ratio, respectively. The heat of vaporization (h fg ) is 2.43·10 6 J/kg. _m res ? 2:58C210 C06 C0C1 M e14T T ex ? 32:6t0:066T a t32W a e15T W ex ? 0:0277t0:000065T a t0:2W a e16T The ratio of the skin mass to total body mass (a)is modeled as the following function of core to skin blood flow: a ? 0:0418t 0:745 e3;600 _m bl t0:585T e17T The blood flow between the core and the skin per unit of skin area is expressed as _m bl ? 6:3t200WSIG cr eT= 1t0:5CSIG sk eT?C138 3;600 e18T The rate of sweat production per unit of skin area is estimated by _m sw ? 4:7C210 C05 WSIG b exp WSIG sk 10:7 C18C19 e19T The average temperature of human body can be pre- dicted by the weighted average of the skin and core temperatures: T b ? aT sk te1C0 aTT cr e20T The neutral body temperature is calculated from the neutral 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 the total evaporative resistance for each segments are as follows [14]: R t eiT?R a eiT rei;0T rei;nlT t X nl j?1 R al ei;jT rei;0T rei;jC01T tR f ei;jT rei;0T rei;jT C20C21 e21T R ev;t eiT?R ev;a eiT rei;0T rei;nlT t X nl j?1 R e;al ei;jT rei;0T rei;jC01T tR e;f ei;jT rei;0T rei;jT C20C21 e22T It is assumed that heat transfer through air layers between clothing layers occurs by conduction and radi- ation. In this case, thermal resistance of an air layer is given by R al ? 1 h rd tk=x a e23T where x a is air layer thickness. The values of h rd and k were taken as h rd =4.9 W/(m 2 K) and k=0.024 W/(mK) [14]. Similar equation can be written for the evaporative resistance. Evaporative resistance of an air layer is given by: 453 R ev;al ? a 1C0exp C0 x a b C16C17hi e24T where a and b are constants. The values of a and b are 0.0334 (m 2 kPa)/W and 15 mm, respectively [14]. The outer surface exposed to the environment is treated a little di?erently. The thermal resistance of the outer layer is then: R a ? 1 h cv th rd e25T The evaporative resistance of the outer layer can be determined from the convective heat transfer coe?cient and the Lewis Relation: R ev;a ? 1 h cv LR e26T 2.2 Prediction of thermal sensation The above equations describe thermal exchange between the human body and the environment and thermoregu- latory control mechanisms. Combination of the thermal energy on the body, thermal load, a?ects the human thermal comfort in the thermal energy exchange (tran- sition) between the body and its environment. If the thermal load (L) on the body is nearly zero, then neu- trality or thermal comfort is achieved. Combinations of activity, clothing and the four environmental variables (air temperature, mean radiant temperature, air velocity and humidity) all a?ect thermal comfort. The most widely used thermal comfort index is the thermal sen- sation (TS) value is given by Eq. 27. TS ? 0:303exp C00:036M A b C18C19 t0:028 C20C21 L e27T where A b is the total surface area of the body. The TS scale is given in the Table 4. 2.3 Assumptions and initials conditions Nude body surface area is taken as A b =1.751 m 2 . Body mass (m) is 80 kg and initial values of core and skin temperatures are taken as 36.8 and 33.7C176C respectively [3]. Summer clothing insulation, winter clothing insula- tion, clothing area factor for summer clothing, clothing area factor for winter clothing and metabolic activity are taken as 0.5 clo, 1.5 clo, f cl = 1.1, f cl = 1.15 and 75 W/m 2 , respectively [5, 6]. Table 4 Scale of TS values 0 thermal neutrality 1 slightly warm C01 slightly cool 2 warm C02 cool 3 hot C03 cold 4 very hot C04 very cold 5 painfully hot C05 painfully cold Fig. 1 Automobile interior air temperature during heating process Fig. 2 Temperatures inside the automobile and human body contact surfaces Fig. 3 Relative humidity values during cooling process inside the automobile 454 Local air velocities on the body is given in the Table 1 and mean air temperature (T a ) for heating and cooling processes is taken as given in Figs. 1 and 2. Relative humidity in heating period is taken as 0.35 [5] and in cooling period it is taken as given in Fig. 3.Mean radiant temperature in heating period is taken as C22 T rd ? 0:94T a C01:38 and in cooling period is taken as C22 T rd ?C00:007752T 2 a t1:625778T a C06:879288: Surface temperatures of solids in contact with the body (T int ) in heating period (t is time from start-up in minutes) were [5]: Seat T int ? 41 1C0exp C0t 4 C16C17C16C17 C020 for t C20 15 T int ? 20t0:367et C015T for t > 15 Clothed area in contact with seat: 0.07 m 2 Back support T int ?C020t30t for t C20 1 T int ? 14:6e1C0exp C0 et C01T 5 C18C19 t10 for 1\t\10 T int ? 22:2t0:065et C010T for t C21 10 Clothed area in contact with back support: 0.07 m 2 Steering wheel T int ? 40 1C0exp C0t 6 C16C17C16C17 C020 Clothed area in contact with steering wheel: 0.01 m 2 . In cooling period, surface temperatures of solids in contact with the body (T int ) are found as follows as a result of performed experiments. (where t is in minutes) (Table 5). T int ? at 2 tbt tc e28T 3 Results and discussions In order to investigate the e?ects of automobile interior conditions resulted by heating and cooling process, the equations given in Mathematical model section are conducted to computer medium by using the program- ming language Delphi 6. For heating period, required experimental input data such as automobile interior air temperature 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 C020 to 20C176C as seen from Fig. 1. Table 5 Constants in the Eq. 28 For t ￡ 2 For t>2 ab c a b c Seat 3.10 C015.30 65.20 0.0051 C00.3870 46.0496 Back support 2.55 C013.65 62.10 0.0049 C00.3306 43.7763 Steering wheel 2.50 C016.00 67.00 0.0064 C00.4618 44.6285 Fig. 4 Comparison of body heat losses in heating process Fig. 6 Average body skin temperature in heating process Fig. 5 Comparison of thermal sensation during heating process 455 Required experimental data for cooling process are measured in 1991 Toyota Corona Sedan automobile equipped with a 2,000-cc engine. Automobile is parked in the sun and it is observed that the increase of tem- perature inside car is 64C176C with the ambient temperature of about 30C176C. Later, standard cooling process is started by running the air conditioning unit. During this process temperature inside car, relative humidity, seat, back support and steering wheel surface temperatures are measured. Measured parameters are shown Figs. 2 and 3. Since relative humidity decreases from 50 to 11% during the increase of temperature inside car to 64C176C, relative humidity in cooling process is started from 11%. Heat losses from body to the environment during warm-up process are given in Fig. 4 comparatively. Since the model of Burch et al. [5] and the present model exhibit some principal di?erences (e.g., the body is divided into four segments in Burch’s 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, the agreement between the results can be acceptable range. Conduction heat losses to the seat, back support and steering wheel is rather low in comparison to the total value of convective and radiative heat losses because the areas of body segments in contact with solid surfaces are smaller than other body surfaces. In the beginning of warm-up process, conductive, convective and radiative heat losses are high since the temperature inside the automobile and the interior surface temperatures are rather low. Even total of these heat losses are higher than metabolic heat generation. For this reason, core and 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 rapid decrease in these heat losses due to increase in the tem- perature inside the automobile. In this process, body tries to keep respiration and evaporation heat losses in minimum to balance heat losses. Comparative variation of TS values in warm-up period is given in Fig. 5. By inspection of Fig. 5, there is a good agreement with the study of Burch et al. [5]. These calculations are performed by considering the same conditions described in the experimental and analytical studies of Burch et al. [4, 5]. In their experi- ments, TS values were obtained by using jury data, and the mean TS and standard deviation (r) of the jury data were calculated versus time. The present study calcula- tions are fall within the range of TS±1r, and the value of r is given as 0.62. In the beginning, time heat losses from the body to the environment is very high due to low temperature inside the car. For this reason, TS indices that considers thermal load on the body has been started from very low values. And then, TS has improved with increasing inside temperature and interior surface temperatures. One of the parameters that indicate the e?ects of environmental conditions on human comfort during the warm-up period of automobile cabin is mean body skin temperature and its variation with time is shown in Fig. 6. In early minutes, average skin temperature instantly decreases due to very low temperatures of both inside the car and interior surfaces. Since temperature inside car increases with time, mean skin temperature increases after its values drops a minimum value of Fig. 7 Temperature of body parts that contact with solid surfaces in heating process Fig. 8 Heat flow between body and environment in cooling process Fig. 9 Variation of thermal sensation during cooling process 456 32C176C. Although average skin temperature gives an idea about the human comfort condition, it must be paid attention local discomforts on human body. The tem- peratures of back, thigh and hand of the body that contact with solid surfaces are given in Fig. 7. The temperatures of back and thigh are not much more a?ected from inside temperatures, and so they don’t vary importantly. But the hand-skin temperature decreases to a value of 17.5C176C that can be evaluated as a rather low temperature. In literature, it is mentioned that hand-skin temperature of 20C176C causes a report of uncomfortably cold; and 15C176C, extremely cold [3]. Heat transfer from the body in cooling process is given in Fig. 8. Since inside temperature and interior surface temperatures are high at the beginning, sensible heat flow (conduction, convection and radiation) occurs from 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 comfort conditions, the heat from environment to body and metabolic heat generation of body must be emitted to environment. For this reason, body increases the sweat generation, and then a large portion of the body is covered by sweat. In this way, evaporative heat loss in- creases as shown in Fig. 8. Whereas respiration loss is not a?ected by ambient conditions and it stays about 10 W. The variation of TS for cooling period is given comparatively with Chakroun and Al-Fahed’s [7] study in Fig. 9. In Chakroun and Al-Fahed’s [7] paper, detailed ambient conditions were not given, so our model could not be applied directly to their measurement conditions. Therefore, this figure presents only a qualitative comparison. In their study, it is ensured the temperature inside car reaches up to approximately 65C176C by parking in the sun. Then, cooling process is investigated by running the A/C unit. But experiments are performed in relatively hot climate and ambient temperature is about 45C176C. However it is about 30C176C in our experiments. And the radiation from the sun is also stronger than our cases. For this reason, temperature profile inside the car is di?erent and depending on this TS values are also di?erent. In early minutes, due to high inside tem- peratures, heat is transferred from environment to the body by conduction, convection and radiation. For this reason, since the body has a significant thermal load, TS starts from very high values. Then, thermal load decreases with decreasing the temperature inside car and the surface temperatures and comfort condi- tion gets better. The variation of mean body, feet, and hand-skin temperatures during the cooling process is given in Fig. 10. In early times, since the temperature inside the car is very high (C2464C176C), the temperatures of the all body segments rise. But, the temperature rise of the hand that directly contacts with air is higher than other segments. Since inside the car cools with time this rise decreases. Hands are most a?ected from ambient conditions, so obvious decrease in tempera- ture occurs on hand. Similar situation is valid for head. Since shoes are important insulation element, feet are not a?ected from the interior temperature variations. For this reason, the highest temperature at the end o