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1、第5章,围护结构节能设计,K R S D,传热系数K：稳定传热条件下，单位温度差推动下于单位时间内经单位传热面所传递的热量,蓄热系数S：当某一足够厚度的单一材料层一侧受到谐波热作用时，通过表面的热流波幅与表面温度波幅的比值。可表征材料热稳定性的优劣。（在周期性热作用下，围护结构或房间抵抗温度波动的能力。）,热惰性指标D，是表征围护结构对周期性温度波在其内部衰减快慢程度的一个无量纲指标，单层结构D=RS；多层结构D=RS。式中R为结构层的热阻，S为相应材料层的蓄热系数，D值愈大，周期性温度波在其内部的衰减愈快，围护结构的热稳定性愈好。,热阻R：代表建筑材料阻止热量穿过的能力。,保温,隔热,稳定传
2、热,波动传热,传热系数K值或传热阻R,热惰性指标R*S,多孔轻质材料R大,多孔轻质材料R大；重质材料S大,冬季阻止室内向室外传热,夏天隔离太阳辐射热和室外高温的影响,240mm砖墙外贴60mm厚ASA复合保温板作外保温（板中间苯板厚度为30mm），其热阻为1.37 mK/W，热惰性指标为4.11，总衰减倍数可达到116.0，总延迟时间11.15小时，具有很好的隔热保温性能。,三棉（岩棉、矿棉、玻璃棉）和苯板都是高效保温材料，重量轻、热导率小，但材料蓄热较小，是高热阻、低热惰性指标材料。,生物电,高压电,夏热冬冷、白天热晚上冷,冬季没采暖要求保温效果不明显夏季太阳辐射厉害，室内外温差小重隔热,冬
3、季采暖期长保温效果明显夏季凉爽，不重隔热,窑洞,外墙采用白色涂料，41mm厚的挤塑聚苯板外保温材料，15mm厚的钢筋混凝土材料重质内墙体的蓄热蓄冷功能,加厚外保温材料，提高隔热性能。高效复合保温材料，轻重搭配，具有较高的热阻、热惰性指标，内墙不宜采用比较厚的重质材料蓄冷隔热 小型混凝土空心砌块。,墙体外侧配置轻质外保温材料，厚度最少在80mm以上。内侧墙体要采用重质钢筋混凝土材料，表面抹灰层要尽可能薄。,墙体节能1蓄热体,Thermal Mass 蓄热体,Thermal Mass,蓄热体是指有能力长时间的存储热能的材料。,有效地吸收白天热（减少冷负荷），并在夜间释放热量（降低热负荷）。,Typ
4、es of Thermal Mass,Traditional types of thermal mass include water,rock,earth,brick,混凝土concrete,纤维水泥fibrous cement,钙质caliche,and瓷砖ceramic tile.Phase change materials store energy while maintaining constant temperatures,using chemical bonds to store&release latent heat.相变材料的储存能量，同时保持恒定的温度，利用化学键的存储和释放
5、潜热。,2.PASIVE COOLING:THERMAL STORAGE SYSTEM,Air moved by fans,Metal plots,Alcala Gres hollow steel container full of melting gels,PCG capsule,ENERGY AND TEMPERATURE STORAGE-DENSE MATERIALS:CERAMIC FLOORING.(sensible heat)-PHASE CHANGING GELS(PCGs)(latent heat),Historical Applications,The use of ther
6、mal mass in shelter dates back to the dawn of humans,and until recently has been the prevailing strategy for building climate control in hot regions.,Egyptian mud-brick storage rooms(3200 years old).,Canyon de Chelly,Arizona,Today,passive techniques such as thermal mass are ironically considered“alt
7、ernative”另类methods to mechanical heating and cooling,yet the appropriate use of thermal mass offers an efficient integration of structure and thermal services.,The lime-pozzolana(concrete)Roman Pantheon,Thermal Properties of Materials,MaterialDensity(kg/m3)Concrete600-2200Stone1900-2500Bricks1500-19
8、00Earth 1000-1500(uncompressed)Earth1700-2200(compressed),The basic properties that indicate the thermal behavior of materials are:density(p),specific heat(cm),and conductivity(k).The specific heat 比热 for most masonry materials is similar(about 0.2-0.25Wh/kgC).Thus,the total heat storage capacity 蓄热
9、能力 is a function of the total mass 质量 of masonry materials,regardless of its type(concrete,brick,stone,and earth).,Thermal Time Constant热时间常数,One of the more important mathematical constructs to imagine the behavior of thermal mass is the Thermal Time Constant of an building envelope,defined as the
10、product of the heat capacity(Q)and the resistance(R)to heat transmission.The TTC is representative of the effective thermal capacity of a building.有很多学者提出了用于衡量围护结构隔热性能的评价指标。如韦延年提出的热阻抗隔热指数和热稳定隔热指数指标；吉沃尼等学者根据电路类比方法提出了热时间常数TTC(Thermal Time Constant)指标；以及民用建筑热工设计规范GB 5017693中采用的内表面最高温度限值指标等等。这些指标在一定程度上可
11、以反映建筑围护结构的隔热性能，但也存在很大的局限。,Example TTC Calculations,Wall 2:interior insulation,Wall 1:exterior insulation,outside,inside,outside,inside,Thermalmass,Thermalmass,TTC=43.8,TTC=7.8,Source:Givoni,insulation,insulation,Diurnal Heat Capacity 热容量日变化,The DHC is a measure of the buildings capacity to absorb so
12、lar energy coming into the interior of the space,and to release the heat to the interior during the night hours.The DHC is of particular importance for buildings with direct solar gain.,DHCper area=F1s,P=period(24hr.),Note that the DHC for a material increases initially with thickness,then falls off
13、 at around 5”.This behavior reflects the fact that after a certain thickness,some of the heat transferred to the surface will be contained in the mass rather than returned to the room during a 24 hour period.,The DHC of a material is a function of building materials density,specific heat,conductivit
14、y,and thickness.The total DHC of a building is calculated by summing the DHC values of each surface exposed to the interior air.,TTC and DHC Examples,Building which is externally insulated with internal exposed mass.Here,both TTC and DHC are high.When the building is ventilated at night and closed d
15、uring the day,it can absorb the heat in the mass with relatively small indoor temperature rise.Best for hot-dry regions.,Building with high mass insulated externally and internally.Here,the building has a high TTC,but a negligible DHC,as the interior insulation separates the mass from the interior.W
16、hen the building is closed and the solar gain is minimized,the mass will dampen the temperature swing,but if the building is ventilated,the effect of the mass will be negated.With solar gain,the inside temperature will rise quickly,as the insulation prevents absorption of the energy by the mass.,Bui
17、lding with core insulation inside two layers of mass.Here the TTC is a function of mostly the interior mass and the amount of insulation,and the DHC is a function on the interior mass.The external mass influences heat loss and gain by affecting the delta T across the insulation.,Building with mass i
18、nsulated internally.Here,both the TTC is and DHC are low.The mass will store energy and release energy mostly to the exterior,and the thermal response is similar to a low mass building.,Strategies,Slow rate of indoor heating in summer(minimize solar gain).Fast rate of indoor cooling and ventilation
19、in summer evenings.Higher indoor temperatures during the day in winter.Slow release of stored heat during winter night.,墙体节能3外墙外保温,What is External Wall Insulation?,A method of upgrading the thermal performance and external appearance of existing properties,Insulated and rendered properties are tran
20、sformed into warm,energy efficient and attractive homes/buildings,Before,After,External Wall Solutions,5.1 外墙外保温技术,外围护墙体节能,外保温体系组成：,1保温隔热层。采用导热系数小的高效保温材料，其导热系数一般小于0.05W/（mk)。2保温隔热材料的固定系统。有的将保温板粘结或钉固在基底上，有的为两者结合，以粘结为主，或以钉固为主。超轻保温浆料可直接涂抹在外墙表面上。3面层。薄面层一般为聚合物水泥胶浆抹面，厚面层则仍采用普通水泥砂浆抹面。有的则在龙骨上吊挂薄板覆面。4零配件与辅助材
21、料。在接缝处、边角处，还要使用一些零配件与辅助材料，如墙角、端头、角部使用的边角配件和螺栓、销钉等，以及密封膏如丁基橡胶、硅胶等，根据各体系的不同做法选用。,Comprise of an insulation layer fixed to the existing wall,with a protective render or decorative finish.Dry cladding干挂 offers a wide range of finishes such as timber panels,stone or clay tiles,brick slips or aluminium pa
22、nels.,External Wall,External Wall Insulation Key Components,External Wall Solutions,Beads and closures,Insulation,Fixings,Reinforcement layer,Base render coat,Finish coat,Choice of Insulation Comparative Performance,External Wall Solutions,Finishes available,External Wall Solutions,Mineral render sc
23、raped texture,Dry dashusing 6-8mmcoloured aggregate,Spray roughcast,Brick slips or brick-effect render,Light synthetic aggregateusing an acrylic binder,外墙外保温的优越性：,1、外保温可以避免产生热桥；,2、外保温有利于保障室内的热稳定性：,outside,inside,outside,inside,Thermalmass,Thermalmass,TTC=43.8,TTC=7.8,insulation,insulation,3、外保温有利于提高
24、建筑结构的耐久性：,4、外保温可以减少墙体内部冷凝现象：,5、有利于既有建筑节能改造：,6.一旦安装较少维护,No internal living space is lost,External Render System,Internal Flexible Lining,聚苯板,EPS板薄抹灰外墙保温系统：,1EPS板薄抹灰系统是国内外使用最普遍、技术上最成熟的外保温系统。该系统EPS板导热系数小，约 在0.0380.041W/(mK)之间，并且EPS板厚度一般不受限制，可满足严寒地区节能设计标准要求，尤适用于寒冷地区和严寒地区。,2高层建筑可有多种防火构造措施，这是欧洲采用的一种做法，在国内
25、 使用需经抗裂试验验证，确保系统面层不会开裂。,3采取适当措施后可贴面砖。,薄抹灰外墙保温系统的性能指标：,胶粉EPS颗粒保温浆料外墙外保温系统：,以聚苯乙烯颗粒为保温材料，加入聚合物水泥胶浆搅拌而成，直接抹在墙体表面为保温层，以耐碱玻纤布为增强层，抗裂层，以防水抗裂砂浆为保护层。外饰面为涂料或其它装饰材料而形成的，对建筑物起到冬季保温，夏季隔热和装饰、保护的效果。,胶粉EPS颗粒保温浆料外墙外保温系统的优点：,1容量小，导热系数较低，保温性能好；2软化系数高，耐水性能好；3静剪切力强，触变性好；4材质稳定，厚度易控制，整体性好；5干缩率低，干燥快。,EPS板现浇混凝土外墙外保温系统（模板）,
26、挤塑型聚苯板,XPS板外保温隔热材料：,1、优良的保温隔热性；2、卓越的高强度抗压性；3、优质的憎水、防潮性；4、质地轻、使用方便；5、稳定性、防腐性好；6、产品环保性能。,挤塑聚苯板倒置式屋面,墙体节能4外墙内保温,5.2 外墙内保温技术,External Render System,Internal Flexible Lining,Internal Dry Lining(Direct Fix),Internal Dry Lining(On Straps),Internal Dry Lining(Filled Studs),Internal Wall Solutions,Rigid boar
27、ds,What are the solutions?,干作业,Internal Wall Solutions,Flexible thermal lining,Rigid board,Case Study Flexible thermal lining,The solutionSempatap is thermal insulation on roll which is applied like wallpaper and at only 10mm thick does not cause significant disruption during installation.,Internal
28、Wall Solutions,Case Study Rigid boards,Internal Wall Solutions,Case Study Flexible thermal lining,Internal Wall Solutions,内保温复合墙体的优点：,1)对饰面和保温材料的防水、耐候性等技术指 标的要求不高，取材方便；2)内保温材料被楼板所分隔，仅在一个层高范 围内施工，施工方便，不需搭设脚手架。,缺点：由于材料、构造、施工等原因，许多内保温复合墙体饰面层容易出现开裂；不便于用户二次装修和吊挂饰物；占用室内使用空间；由于圈梁、楼板、构造柱等会形成热桥，热 损失较大；对既有建筑进
29、行节能改造时，对居民的日常生活干扰较大。,GRC内保温板：,GRC内保温板集围护、保温和装饰于一体，外围护层是6mm的喷射GRC，保温层选用50mm厚聚苯板。GRC是玻璃纤维增强水泥的简称。它是以水泥砂浆作基材,玻璃纤维为增强材料,并加少量化学掺加剂混合而成,采用压缩空气喷射成型的一种无机复合材料。,单一材料外墙：,1）加气混凝土砌块。该墙体轻质高强，热工性能好。2）混凝土空心砌块，外墙采用混凝土空心砌块作为承重材料，孔内填充保温材料，外墙内粉刷保温砂浆作保温处理。3）粘土多孔砖，多层住宅一般采用砖混结构，以粘土多孔砖为墙体。4）框架填充外墙。主要用于高层建筑。可以用水泥炉渣轻质砌块、加气混凝
30、土砌块、大孔空心砖、各种轻质条板等。,墙体节能5保温材料的构造,1.1 AIR BARRIER AND THERMAL ALIGNMENT空气阻隔和热对齐,In order for insulation to be an effective thermal barrier,it should be installed without any gaps,voids,compression,or wind intrusion.Gaps and voids allow air to flow through the insulation,decreasing its effectiveness(Fi
31、gure 1.1.4).Compression reduces the effective R-value of the insulation.,Figure 1.1.3-The air barrier should be contiguous and continuous over the entire building envelope.Insulation should be perfectly aligned with the air barrier.,Image courtesy of Southface Energy Institute,Figure 1.1.4-Gaps(left
32、)and voids(right)allow air to flow through insulation.,The following images depict misalignment between the air barrier and insulation that undermine the performance of the thermal enclosure.,Generally,the Thermal Bypass Inspection Checklist requires a sealed air-barrier on all six sides of insulati
33、on(top,bottom,back,front,left,and right),however,there are a few exceptions as noted throughout the checklist.In Climate Zones 1 thru 3,there is a general exemption for the internal air barrier closest to conditioned space because the predominant direction of air-flow in hot climates is from the out
34、side to the inside of the house.In Climate Zones 4 thru 6,the most critical air-flow is from inside the home to the outside during cold weather,therefore the internal air barrier is required.,Figure 1.1.5 shows a common insulation installation practice called inset stapling where tabs of faced batts
35、 are stapled to the inside edges of wall framing.However,this practice commonly results in large gaps between the insulation and interior finish that will allow convective air flow around the insulation.This also facilitates air leakage at any gaps or holes in the framing.In contrast,stapling the in
36、sulation to the face of the studs would have allowed the batts to fill the framing space and be aligned with the interior finish.Note also how the insulation is also compressed around piping and wiring,resulting in a reduced R-value.,1.1 AIR BARRIER AND THERMAL ALIGNMENT,Figure 1.1.6-Insulation inst
37、alled with gaps and voids,Figure 1.1.5 Misalignment of insulation due to compression,Similarly,in Figure 1.1.6,the large gap between the insulation and where the interior ceiling finish will be installed will allow convective air flow around and through the insulation.,An exception to the six-side a
38、ir barrier requirement discussed earlier is at band joists.However,inside air barriers at band joists are highly encouraged for Climate Zones 4 and higher and in any homes with open web truss-joist floors because as the homes are being heated,driving forces will cause heated air between the floors t
39、o flow through the band joist to the cold exterior framing.This can lead to higher utility bills,discomfort,and potential moisture problems.,Figure 1.5.1 depicts two best practices for ensuring the alignment of an air barrier and thermal barrier at band joists.In the detail at the left,spray foam is
40、 used to fill the entire joist area and acts as a thermal barrier and an air barrier.At right,a small structural insulated panel(SIP)is installed,also acting as both a thermal and air barrier.,Figure 1.5.1-Options for insulation/air barrier alignment at band joists,1.5 AIR BARRIER AT ALL BAND JOISTS
41、带搁栅的空气阻隔,While the alignment of air and thermal barriers is important throughout the home,one specific detail merits further mention.In cold climates,exposed concrete slab edges are a common source of discomfort and high utility bills.Properly insulating the slab edge can dramatically improve home p
42、erformance.,Figure 1.4.1-Options for slab insulation,1.4 SLAB-EDGE INSULATION板边绝缘,There are two basic ways to insulate a slab.First,rigid insulation can be installed directly against the exterior of the slab,as shown in the detail at left in Figure 1.4.1.Note that in areas with high termite populati
43、ons,builders should be careful to avoid installing foam insulation in contact with the ground.A second option is a“floating slab,”which can be constructed using interior insulation,as shown in the detail at right.In both cases,insulation should be continuously aligned with the air barrier.,Diagrams
44、courtesy of the US Department of Energy,2.5 SKYLIGHT SHAFT WALLS天窗侧边保温,Skylight shafts protruding through the ceiling and an unconditioned space need to be insulated since the shafts walls are effectively attic knee walls adjoining an unconditioned space.Skylight shaft walls shall be insulated to th
45、e same level as attic knee walls and shall include a sealed air-barrier aligned with the insulation on both interior and exterior sides of the walls(see Figure 2.5.1).Climate Zones 1 thru 3 are exempt from the sealed interior air-barrier,but this is unlikely to be an issue since skylight shafts are
46、almost always finished.,Skylight,Air Barrier,Air Barrier,Attic,Insulation,Light tubes such as the one pictured in Figure 2.5.2 should also be covered with insulation and an air-barrier.In fact,the light tube depicted includes approximately 30 square feet of exposed surface area to the unconditioned
47、attic.One acceptable method for insulating the light tube is to use R-8 duct insulation with the plastic lining functioning as the exterior air-barrier.Additionally,the penetration of the light tube through the ceiling shall be sealed between conditioned and unconditioned space.See Section 4.1 and 4
48、.2 of this document.,Figure 2.5.1 Architectural detail for insulation and air barrier at skylight shaft,Figure 2.5.2 Example of an un-insulated light tube,4.3 FLUE SHAFT贯穿的管道的保温,Flue penetrations into attics are more complicated because they also need code mandated combustion safety clearances with
49、combustible framing materials.In Figure 4.3.1 below,insulation is used to fill the space between the flue and the studs.However,this is a poor detail because batt insulation is not an effective air barrier and does not meet combustion safety clearances.,Figure 4.3.1-Insulation improperly used as an
50、air barrier,Image courtesy of EnergyLogic,Batt insulation,Figure 4.3.2 shows how a flue can be properly sealed in a large opening.In this case,an OSB panel was cut to fill the air space around the flue.The flue was then fitted with a metal collar to fill the gap needed for combustion safety clearanc
