哈尔滨供暖设计热负荷

1、第一章：采暖设计热负荷计算图2-7为哈尔滨市某学校两层教学楼的平面图。试计算一层101图书馆的采暖设计热负荷。已知条件：采暖室外计算温度twn=-26;冬季主导风向：SSD；冬季室外风速：3.8m/s。室内计算温度：101图书馆16。围护结构：外墙：二砖墙（490mm），外表面水泥砂浆抹面，内表面水泥砂浆抹面、白灰粉刷、厚度均为20mm；外窗：双层木框玻璃窗C-1，尺寸为2000mm*2000mm（冬季用密封条封窗）：外门：双层木框玻璃门M-1，尺寸为4000mm*3000mm：层高：4m（从本层地面上表面算到上层地面上表面）：地面：不保温地面：屋面：构造如图2-8.解：一、确定围护结构的传热

2、系数K（1） 查表1-1、表1-2、附录1-3得到：围护结构内表面换热系数n=8.7w/(·)外表面换热系数w=23w/(·)外表面水泥砂浆抹面导热系数1=0.87 w/(m·)内表面水泥砂浆地面、白灰粉刷导热系数2=0.87 w/(m·)红砖墙导热系数3=0.81w/(m·)外墙传热系数K计算得K=11n+1w+ii=10.020.87+123+0.020.87+0.490.81+18.7=1.24w/(·)(2)屋面：屋面的构造如图2-8，查表得：内表面换热系数n=8.7w/(·)板下抹混合砂浆1=0.87 w/(m&#

3、183;) 1=20mm屋面预制空心板2=1.74 w/(m·) 2=120mm1:3水泥砂浆 3=0.87 w/(m·) 3=20mm一毡二油 4=0.17 w/(m·) 4=5mm膨胀珍珠岩 5=0.07 w/(m·) 5=100mm1:3水泥砂浆 6=0.87 w/(m·) 6=20mm三毡四油卷材防水层7=0.17 w/(m·) 7=10mmwumianXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

4、XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX外表面换热系数w=23w/(·)屋面传热

5、系数为K=11n+1w+ii=10.020.87+0.121.74+0.0050.17+123+0.020.87*3+0.490.81+18.7=0.55w/(·)（3）外门、外窗：查附录1-4，双层木框玻璃窗K=2.68 w/(·)双层木框玻璃门K=2.68 w/(·)wumianXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

6、XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX（4）地面：不保温地面，按表1-5取各地带传热系数。二、101图书馆计算：1、围护结构基本耗热量Q1（1）南外墙：南外墙传热系数K=1.24 w/(·

7、)，温差修正系数=1，传热面积F=(6.0+0.37)*4-(2*2*2)=17.48按公式（1-3）计算南外墙的基本耗热量Q1KF(tn-twn) 1.24*17.48*(16+26)*1910.36W查附录1-5得哈尔滨南向的朝向修正率，取-17%则朝向修正耗热量Q1910.36*(-0.17) -154.76W本教学楼不需要进行风力修正，高度未超过4米也不需要进行修正。wumianXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

8、XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX南外墙的实际耗热量Q1Q1+ Q1910.36-154.76755.6W(2)南外窗

9、：南外窗传热系数K=2.68 w/(·).，传热面积F=2*2*2=8（两个外窗）基本耗热量Q1KF(tn-twn) 2.68*8*(16+26)*1900.48W朝向修正耗热量wumianXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

10、XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXQ1900.48*（-0.17）-153.08WwumianXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

11、XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX南外窗实际耗热量wumianXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

12、XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

13、XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX Q1Q1+ Q1900.48-153.08747.40W(3)东外墙：东外墙传热系数K=1.24 w/(·)，温差修正系数=1，传热面积F=(4.5+0.37)*4-2*2=15.48基本耗热量Q1KF(tn-twn) 1.24*15.48*（16+26）*1806.20W查附录1-5得哈尔滨东向的朝向修正率，取+5%则朝向修正耗热量Q1806.20*（+5%）40.31W东外墙实际耗热量wumianXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

14、XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

15、XXXX Q1Q1+ Q1806.20+40.31846.51W(4)东外窗：东外窗传热系数K=2.68 w/(·)，温差修正系数=1，传热面积F=2*2=4基本耗热量Q1KF(tn-twn) 2.68*4*（16+26）*1450.24W朝向修正耗热量wumianXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

16、XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXQ1450.24*（+5%）22.51W东外窗实际耗热量wumianXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

17、XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX Q

18、1Q1+ Q1450.24+22.51472.75W（5）地面：地面划分地带如图2-9第一地带传热系数K1=0.47 w/(·)F1=（6.0-0.12）*2+（4.5-0.12）*2=20.52第一地带传热耗热量Q1= K1F1(tn-twn) 0.47*20.52*（16+26）*1405.06W第二地带传热系数K20.23 w/(·)F2（3.88+0.38）*28.52第二地带传热耗热量Q2= K2F2(tn-twn) 0.23*8.52*（16+26）82.3W第三地带传热系数K30.12 w/(·)F31.88*0.380.71第三地带传热耗热量Q3=

19、 K3F3(tn-twn) 0.12*0.71*（16+26）3.58所以地面的传热耗热量Q1Q1+Q2+Q3405.06+82.3+3.58490.94综上，101图书馆围护结构的总传热耗热量Q1Q1南墙+Q1南窗+Q1东墙+Q1东窗+Q1地755.60+747.40+846.51+472.75+490.943313.20W2、冷风渗透耗热量（按缝隙法计算）（1）南外窗，如图2-10外窗为四扇，带上亮，两侧窗扇可开启，中间两扇固定。外窗（两个）缝隙总长为L（1.5*4+0.5*8）*220m（包括气窗）查表1-6，在3.8m/s的风速下双层木窗每米缝隙每小时渗入的冷空气量为2.84m

20、79;/(m·h)由于采用密封条封窗，渗入量减少。L。2.84*0.61.70 m ³/(m·h)据twn-26查的w1.4/m ³查附录1-5，哈尔滨南向修正系数n1.00由公式VL。ln1.70*10*1.0034m ³/h得南外窗冷风渗透耗热量Q20.287VwCp（tn-tw）0.287*1*1.4*34*（16+26）555.78W（2）东外窗，如图2-10缝隙长度l1.5*4+0.5*810m（包括气窗）哈尔滨的东向修正系数n0.20东外窗的冷空气渗入量VL。ln1.70*10*0.203.4 m ³/h东外窗冷风渗透耗热

21、量Q20.287VwCp（tn-tw） 0.287*1*1.4*3.4*(16+26) 57.38W3、图书馆的总耗热量为QQ1+Q23313.20+(555.78+57.38) 3926.36W房间热负荷计算房间编号房间名称围护结构室内计算温度（）室外计算温度（）计算温度差（）温度修正系数围护结构传热系数KW/()基本耗热量Q（w）附加率（%）实际耗热量Q（w）名称及朝向尺寸长*宽(m*m)面积F（）朝向风力外门123456789101112131415101图书馆南外墙（60+0.37）*4-（2*2*2）17.4816-264211.24910.36-17755.60南外窗2*2*282

22、.68900.48-17747.40东外墙（45+0.37）*4-2*215.481.24806.20+5846.51东外窗2*242.68450.24+5472.75地面一（60-012）*2+（4.5-0.12）*220.520.47405.06405.06地面二（388+0.38）*28.520.2382.3082.30地面三188*0.380.710.123.583.58围护结构耗热量3313.20冷风渗透耗热量615.7房间总耗热量3928.96散热器面积及片数的计算：已知：房间设计热负荷Q=4000W；tpj=（95+70）/2=82.5; tn=16; t= tpjtn=82.5

23、18=64.5;室内安装采用M-132型散热器，散热器明装，供暖系统为双管上供式，设计供回水温度为：95/70 支管与散热器同侧连接，上进下出。查附录21，对M-132型散热器K=2.426t0.286=2.426*(64.5)0.286=7.99 w/(·)修正系数：散热器组装片数修正系数：先假定11.0散热器连接形式修正系数：查附录2-4，2=1.0散热器安装形式修正系数：查附录2-5，3=1.02据式：FQKt123=40007.99*64.5*1.0*1.0*1.02=7.92M-132型散热器每片散热面积为0.24,计算片数n为：n7.91/0.2433片查附录得当散热器片

24、数为20以上时1=1.10因此实际所需散热器面积为：F=F*1=7.92*1.10=8.72实际采用片数n为：n=Ff=8.720.24=36.33片 取整得 应采用M-132型散热器36片根据计算可知101房间的热负荷总计为4000W，且有四个散热器，每个散热器的热负荷如下图所示，热媒参数供回水温度：95/70,确定供暖系统的并计算出101房间的系统阻力：1、 在图上进行管段编号，水平管与跨越管编号并注明了各管段的热负荷和管长。如右图所示。2、 计算各管段管径：水平管段：1、3、5、7、9的流量为：G=0.86Qtg-th=0.86*400095-70=137.6kg/h根据管径分流系数知跨越管段2、4、6、8均采用DN15，则=0.36，则这些管段的流量：Gk=（10.36）G=0.64*137.6=88.1kg/h根据以上计算可以确定各管段的管径，见下表；3、 各管段的局部阻力系数的确定，见下表：4、 跨越管的局部阻力与沿程阻力计算：跨越管2、4、6、8的阻力相等，假设长度L=1.2m，R=25.86Pa/m，v=0.13m