建筑环境学chapter41-2 thermal comfortable教材

1、4 Energy Use in Buildings （建筑能耗建筑能耗）use energy for lighting, heating or cooling.energy use and built environment ?use the minimum energy to achieve a best comfort built environment.To be energy efficient.this chapter describes:4.1 Energy use 4.2 Thermal comfort 热舒适热舒适4.3 Heat losses 失热量失热量4.4 Heat g

2、ains 得热量得热量4.5 Heat balance 热平衡热平衡4.6 Energy consumption 能耗能耗 4.1 Energy use4.1.1 Energy terms 关于能源的术语关于能源的术语（1） A fuel 燃料 is a substance that is s source of energy（2）fossil fuels 化石燃料化石燃料 coal, crude oil and natural gas（3）non-renewable energy 不可再生能源不可再生能源 which can only be used once fossil fuels（4）

3、renewable energy 可再生能源可再生能源 which are replenishable可补给的 wind power, wave power潮汐能潮汐能 （5）primary energy 一次能源一次能源 coal，oil，natural gas（6）transformation 能源的转化能源的转化Fuels electricity, crude oil petroleum（7）secondary energy 二次能源二次能源 which results from a transformation process.Electricity, manufactured gas

4、人工燃气人工燃气, surplus hot water 废热水废热水The secondary energy of electricity is only 30 to 40 per cent of the primary energy contained in the original fuelsThe rest is lost in the conversion and distribution processes.（8）delivered energy 输出能源输出能源Is energy content as it is received by the consumer.Pay for m

5、oney（9）useful energy有用能有用能Is the energy required to perform a given task.It is useful energy that is required to balance the heat loss and heat gain in a typical calculation.Example:Coalelectricity delivered energyuseful energy4.1.2 Energy units 能量单位Joule焦耳焦耳Megajoules 1MJ=106J Gigajoules 1GJ=109JTo

6、nne of oil equivalent 吨石油当量1 tonne of oil equivalent = 41.87 gigajoules = 107 kilocalcories = 11630 kWh = 396.8 therms 它近似地是能当量烧它近似地是能当量烧100 100 立方英尺立方英尺天然气天然气. .4.1.3 calorific values 热值Units: KJ/kg; MJ/kg KJ/m3; MJ/m3Some typical calorific values are quoted in table 4.1Table 4.2 shows national ene

7、rgy consumption 4.2 What is Thermal Comfort?- That condition of mindwhich expresses satisfactionwith the thermal environment.ISO 7730DefinitionThermal Comfort is a matter of many parameters - Not only the air temperature.4.2.1 Factors affecting thermal comfortPersonal variables 个人因素 Activity Clothin

8、g Age SexPhysical variables 物理因素 Air temperature Surface temperature Air movement humiditylThe Six Basic Factors人环奖试题：6、夏季潮湿的空气环境导致人体不舒适的原因是（ ）A、高湿导致皮肤湿润度增加带来粘滞感，使人感到不舒适B、高湿度导致大气压力降低，从而使人感到不适C、高湿度导致人体热量散不出去，因而使人感到闷热D、高湿度导致人体的汗出不来，因而使人感到闷热Body Temperature 体温体温 Normal body core temperature: 37 oC. We

9、have separate Heat- and Cold-sensors.Heat sensor热感受器热感受器 is located in hypothalamus下丘脑下丘脑 . Signals when temperature is higher than 37 oC.Cold sensors 冷感受器冷感受器are located in the skin. Send signals when skin temperature is below 34 oC. Heating mechanism:Reduced blood flow减少血液流动减少血液流动.Shivering发抖发抖. C

10、ooling mechanism: Increased blood flow加速血液流动加速血液流动. Sweating (Evaporation)出汗出汗.HotCold37 oC34 oCPerception of Thermal Environment人对热环境的知觉 Heat sensor in Hypothalamus下下丘脑丘脑send impulses 脉冲脉冲when temperature exceeds 37 oC. Cold sensors sends impulses when skin temperature below 34 oC. The bigger tempe

11、rature difference, the more impulses. If impulses are of same magnitude等量等量, you feel thermally neutral热中性热中性. If not, you feel cold or warm. WarmimpulsesColdimpulsesActivitythermally neutral and thermal comfortable 中性和舒适之间的关系 冷热刺激的存在冷热刺激的存在 刺激的延续时间刺激的延续时间 人体原有的状态人体原有的状态The Energy Balance能量平衡Thermal

12、 Comfort can only be maintained when heat produced by metabolism代谢 equals the heat lost from body.HeatLostHeatProdu-ced The transfer of the heat from the body is mainly by the process of convection, radiation and evaporation lThe dry heat loss (R+C) represents 70% at low Clo-values and 60% at higher

13、 Clo-valuesl Conduction (K) is normally insignificant compared to the total heat exchangeThe Energy Balance能量平衡6次课结束Heat Balance Equation热平衡方程热平衡方程 General heat balanceS = M - W - E - (R + C)whereS = rate of heat storage of human body 蓄热率M = metabolic rate 代谢率W = mechanical work done by human body 机

14、械功E = rate of total evaporation loss 人体的蒸发（汗液蒸发和呼出的水蒸气）散热率R + C = dry heat exchange through radiation & convection 人体外表面通过辐射和对流的散热率 S=0 S=0 并不一定表示人体处于舒适状态。并不一定表示人体处于舒适状态。 各种热量之间许多不同的组合都可以使各种热量之间许多不同的组合都可以使S=0S=0，即人们会遇，即人们会遇到各种不同的热平衡到各种不同的热平衡 只有那种人体按正常比例散热的热平衡，才是舒适的只有那种人体按正常比例散热的热平衡，才是舒适的 人体正常散热比例人体正

15、常散热比例“ 对流换热占对流换热占2530%2530% 辐射散热占辐射散热占45%50%45%50% 呼吸和无感觉蒸发散热占呼吸和无感觉蒸发散热占2530%2530% 这种处于舒适状态下的人体热平衡，称为人体正常热平衡。这种处于舒适状态下的人体热平衡，称为人体正常热平衡。 0.8 Met 1 Met 8 Met 4 MetMetabolic rate, M 代谢率Met Value Examples1 met = seated quiet person (100 W if body surface area is 1.7 m2);The output from adult females of

16、 males.1met=58.2W/m2Met Value ExamplesWalking 3.5 km/h2.5 METJogging8 METAfter 10 METMet Value ExamplesTable 4.3 lists typical heat outputs from an adult male 人环奖试题：在在3030的空气环境中，人体的发热量与在的空气环境中，人体的发热量与在2222的空的空气环境中相比（气环境中相比（ ）A A、更多，因为人体出汗蒸发促进散热、更多，因为人体出汗蒸发促进散热B B、更多，因为高温会导致人体代谢率增加、更多，因为高温会导致人体代谢率增加C

17、 C、更少，因为皮肤与空气的温度减少了、更少，因为皮肤与空气的温度减少了D D、变化不大，因为发热量主要取决于人体的活动、变化不大，因为发热量主要取决于人体的活动量量 1 Clo = Insulation value of 0,155 m2 oC/Wrange form 0clo to 4clo. table 4.4 shows the value of different types of clothing0,15 Clo0.5 Clo1.0 Clo1.2 Clo Clothing : act as a thermal insulator for the body Calculation o

18、f Clo-value (Clo)Clothing : act as a thermal insulator for the body 服装的蒸发换热热阻服装的蒸发换热热阻( (干燥服装干燥服装) )：I Ie,cle,cl = = I Icl cl / / LRLR = = I Icl cl / 16.5 / 16.5 (kPa(kPam m2 2/W)/W) 服装被汗湿润后热阻会下降，服装被汗湿润后热阻会下降，显热换热加强，又增加了潜热显热换热加强，又增加了潜热换热，故总传热系数增加。换热，故总传热系数增加。Evaporative heat loss, E 人体蒸发散热量人体蒸发散热量 呼

19、吸散热散湿量呼吸散热散湿量(i) Latent Respiration Heat Loss, Erel 呼吸时的潜热散热量呼吸时的潜热散热量(ii) Convective or Sensible Respiration Heat Loss, Erec 皮肤蒸发散热量皮肤蒸发散热量(i) Evaporative Heat Loss by Skin Diffusion, Edif 皮肤湿扩散散热量皮肤湿扩散散热量(ii) Heat Loss due to Regulatory Sweating, Ersw汗液蒸发散热量汗液蒸发散热量 E = Eres + Esk = Erel + Erec + E

20、dif + Ersw Dry heat exchange, R + C 干热交换 C= fcl hc (tcl ta ) mean radiant temperature (tr) is that uniform temp. of an imaginary black enclosure which result in the same heat loss by radiation as the actual enclosureMean radiant temperature .AA.tAtAt212211r M-W-C-R-E=0 M-W-C-R-E=0 （S=0S=0） developed

21、 by Prof. P. O. Fanger (Denmark) Fangers comfort equation: f (M, Icl, V, tr, tdb, Ps) = 0where M = metabolic rate (met)Icl = cloth index (clo)V = air velocity (m/s)tr = mean radiant temp. (oC)tdb = dry-bulb temp. (oC)Ps = water vapour pressure (kPa)Predication of Thermal Comfort热舒适的预测热舒适的预测Predicati

22、on of Thermal Comfort热舒适的预测热舒适的预测 Fangers equation is complex but it may be transformed to comfort diagrams it can also be used to yield three indices: predicted mean vote (PMV) predicted percentage of dissatisfied (PPD)Predicted Mean Vote scale- +3 Hot- +2 Warm- +1 Slightly warm- +0 Neutral- - 1 Sl

23、ightly cool- -2 Cool- -3 ColdThe PMV index is used to quantify the degree of discomfortCalculation of PMV indexPMV = (0,303e-2,100*M + 0,028)*58,15*(M-W)-3,05*10-3*5733-406,7*(M-W)-pa-24,21*(M-W)-1-10-3*M*(5867-pa)-0,0814*M*(34-ta)-3,96*10-8*fcl*(tcl+273)4 - (teq+273) 4 - fcl*hc,eq*(tcl-teq) hc,eq =

24、 2,38*(tcl - teq )0,25 fclM MET)Icl CLO1,00+0,2*Icl for Icl 0,5 cloPMV = (0,303e-2,100*M + 0,028)*(M-W)- H - Ec - Cres - EresPMV ?PMV and PPD PMV-index (Predicted Mean Vote) predicts the subjective ratings of the environment in a group of people. PPD-index predicts the number of dissatisfied people.

25、http:/ ISO7730对PMV-PPD指标的推荐值是PPD10% 即PMV在-0.5+0.5Thermal comfort meter Just set the metabolic and clothing resistance Just for enclosed space and RH not larger than 90% Not suitable for extreme heat surrounding Predication of Thermal Comfort热舒适预测热舒适预测express thermal comfort in a single number by com

26、bining 2 or more comfort parameters operative temperature, 操作温度操作温度to weighted sum of tdb and tr:crdbcrrohhththt effective temperature, ET 有效温度有效温度 干球温度、湿度、空气流速对人体温暖感或冷干球温度、湿度、空气流速对人体温暖感或冷感影响的综合数值，该数值等于产生相同感觉感影响的综合数值，该数值等于产生相同感觉的静止饱和空气的温度的静止饱和空气的温度 请你描述一下请你描述一下 ET=26的热感觉的热感觉美国学者美国学者Gagge盖奇盖奇with his

27、 colleges :根据人体的生理条件，综合考虑了物理学、生理学、根据人体的生理条件，综合考虑了物理学、生理学、心理学三个方面因素提出来的心理学三个方面因素提出来的特别适用于评价高温高湿的环境，但它实际上是通特别适用于评价高温高湿的环境，但它实际上是通用的、不受限制的。用的、不受限制的。Standard effective temperature ，SET 标准有效温度标准有效温度Standard effective temperature 标准有效温度标准有效温度 身穿标准热阻服装的人，在相对湿度为身穿标准热阻服装的人，在相对湿度为50%，空气静，空气静止不动，空气温度等于平均辐射温度的等

28、温环境下，止不动，空气温度等于平均辐射温度的等温环境下，若与他在实际环境和实际服装热阻条件下的感觉相同，若与他在实际环境和实际服装热阻条件下的感觉相同，则该温度就是上述实际环境的标准有效温度。则该温度就是上述实际环境的标准有效温度。Comfort Temperature1,7 CLO2,5 METRH=50%tco=6oC.0,8 CLO2,2 METRH=50%tco=18oC.0,5 CLO1,2 METRH=50%tco=24,5oC.What should be measured?Parameters to measure are:- taAir Temperature- trMean

29、 Radiant Temperature- vaAir Velocity- paHumidityLocal Thermal Discomfort局部热不舒适Draught 吹风感吹风感Radiation Asymmetry 不均匀辐射不均匀辐射Vertical Air Temperature Differences. 垂直温差垂直温差Floor temperature 地板温度地板温度Vertical Air Temperature Difference Vertical Air Temperature Difference is the difference between Air Temperature at ankle and neck level.Vertical Air Temperature DifferenceDissatisfied25 oC19 oCFloor Temperature Acceptable floor temperatures ranging from 19 to 29 oC. The graph is made on the assumption th