一、供熱系統與(yu)介質(zhi)
集(ji)(ji)中(zhong)供(gong)(gong)(gong)熱(re)(re)(re)(re)(re)(re)(re)系(xi)統(tong)(tong)(tong)(tong)是指(zhi)(zhi)一個或多個集(ji)(ji)中(zhong)的(de)(de)(de)熱(re)(re)(re)(re)(re)(re)(re)源(yuan)，通過供(gong)(gong)(gong)熱(re)(re)(re)(re)(re)(re)(re)管(guan)網向多個熱(re)(re)(re)(re)(re)(re)(re)用(yong)(yong)(yong)(yong)戶(hu)(hu)供(gong)(gong)(gong)應(ying)熱(re)(re)(re)(re)(re)(re)(re)能的(de)(de)(de)系(xi)統(tong)(tong)(tong)(tong)，它主要由熱(re)(re)(re)(re)(re)(re)(re)源(yuan)、熱(re)(re)(re)(re)(re)(re)(re)網和熱(re)(re)(re)(re)(re)(re)(re)用(yong)(yong)(yong)(yong)戶(hu)(hu)組成。其中(zhong)熱(re)(re)(re)(re)(re)(re)(re)源(yuan)是指(zhi)(zhi)將(jiang)天然(ran)或人造的(de)(de)(de)能源(yuan)形(xing)態轉化為(wei)符合(he)供(gong)(gong)(gong)熱(re)(re)(re)(re)(re)(re)(re)要求的(de)(de)(de)熱(re)(re)(re)(re)(re)(re)(re)能裝置(zhi)。熱(re)(re)(re)(re)(re)(re)(re)網是指(zhi)(zhi)由熱(re)(re)(re)(re)(re)(re)(re)源(yuan)向熱(re)(re)(re)(re)(re)(re)(re)用(yong)(yong)(yong)(yong)戶(hu)(hu)輸(shu)送和分配供(gong)(gong)(gong)熱(re)(re)(re)(re)(re)(re)(re)介質(zhi)的(de)(de)(de)管(guan)道系(xi)統(tong)(tong)(tong)(tong)，熱(re)(re)(re)(re)(re)(re)(re)用(yong)(yong)(yong)(yong)戶(hu)(hu)是指(zhi)(zhi)從熱(re)(re)(re)(re)(re)(re)(re)源(yuan)獲得熱(re)(re)(re)(re)(re)(re)(re)能的(de)(de)(de)用(yong)(yong)(yong)(yong)熱(re)(re)(re)(re)(re)(re)(re)裝置(zhi)。集(ji)(ji)中(zhong)供(gong)(gong)(gong)熱(re)(re)(re)(re)(re)(re)(re)系(xi)統(tong)(tong)(tong)(tong)分類方式(shi)有三(san)種，可(ke)以根(gen)據(ju)(ju)熱(re)(re)(re)(re)(re)(re)(re)源(yuan)分類、根(gen)據(ju)(ju)熱(re)(re)(re)(re)(re)(re)(re)媒分類、根(gen)據(ju)(ju)供(gong)(gong)(gong)熱(re)(re)(re)(re)(re)(re)(re)管(guan)網分類。集(ji)(ji)中(zhong)供(gong)(gong)(gong)熱(re)(re)(re)(re)(re)(re)(re)系(xi)統(tong)(tong)(tong)(tong)按熱(re)(re)(re)(re)(re)(re)(re)源(yuan)形(xing)式(shi)的(de)(de)(de)不(bu)同可(ke)分為(wei)：熱(re)(re)(re)(re)(re)(re)(re)電廠供(gong)(gong)(gong)熱(re)(re)(re)(re)(re)(re)(re)系(xi)統(tong)(tong)(tong)(tong)、區域鍋爐房供(gong)(gong)(gong)熱(re)(re)(re)(re)(re)(re)(re)系(xi)統(tong)(tong)(tong)(tong)、地熱(re)(re)(re)(re)(re)(re)(re)供(gong)(gong)(gong)熱(re)(re)(re)(re)(re)(re)(re)系(xi)統(tong)(tong)(tong)(tong)、工業余(yu)熱(re)(re)(re)(re)(re)(re)(re)供(gong)(gong)(gong)熱(re)(re)(re)(re)(re)(re)(re)系(xi)統(tong)(tong)(tong)(tong)、核供(gong)(gong)(gong)熱(re)(re)(re)(re)(re)(re)(re)堆和太陽能供(gong)(gong)(gong)熱(re)(re)(re)(re)(re)(re)(re)系(xi)統(tong)(tong)(tong)(tong)等(deng)。集(ji)(ji)中(zhong)供(gong)(gong)(gong)熱(re)(re)(re)(re)(re)(re)(re)系(xi)統(tong)(tong)(tong)(tong)根(gen)據(ju)(ju)熱(re)(re)(re)(re)(re)(re)(re)媒不(bu)同分為(wei)蒸汽供(gong)(gong)(gong)熱(re)(re)(re)(re)(re)(re)(re)系(xi)統(tong)(tong)(tong)(tong)和熱(re)(re)(re)(re)(re)(re)(re)水供(gong)(gong)(gong)熱(re)(re)(re)(re)(re)(re)(re)系(xi)統(tong)(tong)(tong)(tong)。
熱水熱力網(wang)供熱介質設計(ji)(ji)壓(ya)力小(xiao)于(yu)(yu)(yu)或(huo)等(deng)(deng)于(yu)(yu)(yu)2.5MPa，設計(ji)(ji)溫度小(xiao)于(yu)(yu)(yu)或(huo)等(deng)(deng)于(yu)(yu)(yu)200℃；蒸汽(qi)熱力網(wang)供熱介質設計(ji)(ji)壓(ya)力小(xiao)于(yu)(yu)(yu)或(huo)等(deng)(deng)于(yu)(yu)(yu)1.6MPa，設計(ji)(ji)溫度小(xiao)于(yu)(yu)(yu)或(huo)等(deng)(deng)于(yu)(yu)(yu)350℃。
對民用(yong)建筑物(wu)采暖、通風、空調及生活熱(re)(re)水熱(re)(re)負荷供(gong)熱(re)(re)的城市(shi)熱(re)(re)力網，宜采用(yong)水作供(gong)熱(re)(re)介(jie)質(zhi)。
對生(sheng)產工(gong)(gong)(gong)藝熱(re)(re)(re)負荷和采(cai)(cai)(cai)暖、通風(feng)、空(kong)調(diao)、生(sheng)活熱(re)(re)(re)水(shui)熱(re)(re)(re)負荷供(gong)熱(re)(re)(re)的城市(shi)熱(re)(re)(re)力網供(gong)熱(re)(re)(re)介(jie)質(zhi)(zhi)(zhi)按(an)下列(lie)原則確定：當(dang)(dang)生(sheng)產工(gong)(gong)(gong)藝熱(re)(re)(re)負荷為主(zhu)要(yao)負荷，且必須采(cai)(cai)(cai)用蒸(zheng)(zheng)汽(qi)供(gong)熱(re)(re)(re)時(shi)(shi)，宜采(cai)(cai)(cai)用蒸(zheng)(zheng)汽(qi)作(zuo)供(gong)熱(re)(re)(re)介(jie)質(zhi)(zhi)(zhi)；當(dang)(dang)以水(shui)位供(gong)熱(re)(re)(re)介(jie)質(zhi)(zhi)(zhi)能夠滿足生(sheng)產工(gong)(gong)(gong)藝需要(yao)（包括在用戶處(chu)轉換(huan)為蒸(zheng)(zheng)汽(qi)），且技(ji)術(shu)經(jing)濟(ji)合理(li)時(shi)(shi)，宜采(cai)(cai)(cai)用水(shui)作(zuo)供(gong)熱(re)(re)(re)介(jie)質(zhi)(zhi)(zhi)；當(dang)(dang)采(cai)(cai)(cai)暖、通風(feng)、空(kong)調(diao)熱(re)(re)(re)負荷為主(zhu)要(yao)負荷，生(sheng)產工(gong)(gong)(gong)藝又必須采(cai)(cai)(cai)用蒸(zheng)(zheng)汽(qi)供(gong)熱(re)(re)(re)，經(jing)技(ji)術(shu)經(jing)濟(ji)比較認為合理(li)時(shi)(shi)，可采(cai)(cai)(cai)用水(shui)和蒸(zheng)(zheng)汽(qi)兩種供(gong)熱(re)(re)(re)介(jie)質(zhi)(zhi)(zhi)。
1. 國家(jia)現行標準GJJ／T 34《城鎮(zhen)供熱(re)(re)(re)(re)(re)管網(wang)(wang)設計(ji)規范》適(shi)用于(yu)(yu)(yu)(yu)供熱(re)(re)(re)(re)(re)熱(re)(re)(re)(re)(re)水介質設計(ji)壓(ya)力小(xiao)于(yu)(yu)(yu)(yu)或等于(yu)(yu)(yu)(yu)2.5MPa，設計(ji)溫度小(xiao)于(yu)(yu)(yu)(yu)或等于(yu)(yu)(yu)(yu)200℃；供熱(re)(re)(re)(re)(re)蒸汽介質設計(ji)壓(ya)力小(xiao)于(yu)(yu)(yu)(yu)或等于(yu)(yu)(yu)(yu)1.6MPa，設計(ji)溫度小(xiao)于(yu)(yu)(yu)(yu)或等于(yu)(yu)(yu)(yu)350℃的(de)下列(lie)城鎮(zhen)供熱(re)(re)(re)(re)(re)管網(wang)(wang)的(de)設計(ji)：以熱(re)(re)(re)(re)(re)電廠或鍋爐房為熱(re)(re)(re)(re)(re)源，自熱(re)(re)(re)(re)(re)切至建筑物熱(re)(re)(re)(re)(re)力人口的(de)供熱(re)(re)(re)(re)(re)管網(wang)(wang)，供熱(re)(re)(re)(re)(re)管網(wang)(wang)新建、擴建或改建的(de)管道、中斷(duan)泵(beng)站和熱(re)(re)(re)(re)(re)力站等工(gong)藝(yi)系(xi)統。
2. 國家現行標準GJJ／T 81《城鎮(zhen)供(gong)熱(re)直埋(mai)熱(re)水管道技術規(gui)程》適用于(yu)(yu)(yu)新建、改建、擴建的設計(ji)(ji)(ji)溫度小(xiao)于(yu)(yu)(yu)或(huo)等(deng)(deng)于(yu)(yu)(yu)150℃、設計(ji)(ji)(ji)壓力小(xiao)于(yu)(yu)(yu)或(huo)等(deng)(deng)于(yu)(yu)(yu)2.5MPa，DN小(xiao)于(yu)(yu)(yu)或(huo)等(deng)(deng)于(yu)(yu)(yu)1200mm的城鎮(zhen)供(gong)熱(re)直埋(mai)熱(re)水管道的設計(ji)(ji)(ji)、施(shi)工、驗收(shou)和(he)運行管理(li)。
3. 國家現行標準GJJ／T 104《城鎮供熱直埋蒸汽(qi)管道技術規(gui)程(cheng)》適用于工作壓(ya)力(li)小于或(huo)等(deng)于2.5MPa，溫度小于或(huo)等(deng)于350℃，直接(jie)埋地(di)敷設的鋼質外護(hu)蒸汽(qi)保溫管道的設計、施工、驗收及運行維護(hu)。
二、熱力(li)網的(de)形式(shi)
供熱管(guan)網(wang)(wang)按(an)其平面布置形(xing)式可分為枝狀管(guan)網(wang)(wang)、環狀管(guan)網(wang)(wang)和多管(guan)制管(guan)網(wang)(wang)。其特點是(shi)：
1. 枝狀管網
從熱(re)(re)源(yuan)引出主(zhu)干(gan)線(xian)沿(yan)城(cheng)鎮道路向各熱(re)(re)用戶(hu)供熱(re)(re)，形(xing)成類似樹枝狀(zhuang)的(de)管網叫枝狀(zhuang)管網。枝狀(zhuang)管網是目(mu)前我國城(cheng)鎮供熱(re)(re)中普遍采用的(de)形(xing)式(shi)，它(ta)形(xing)式(shi)簡單、投(tou)資費用低(di)，且運(yun)行管理方(fang)便，但(dan)安全可靠性較差(cha)，當管網中距離熱(re)(re)源(yuan)較近的(de)主(zhu)干(gan)線(xian)發生故障時(shi)，會(hui)影(ying)響較多的(de)熱(re)(re)用戶(hu)用熱(re)(re)。
2. 環狀管網
供(gong)熱管網的(de)主(zhu)干線(xian)之(zhi)間在適(shi)當位置連通(tong)構成(cheng)環形(xing)，環狀(zhuang)管網運行較安全可靠(kao)，局部發生故障可通(tong)過環網供(gong)熱。但(dan)投資費用高。
3. 多管(guan)制管(guan)網
一般(ban)用(yong)于以下情況：不能間斷的熱(re)(re)用(yong)戶；供熱(re)(re)系統(tong)中熱(re)(re)用(yong)戶所需介質參數差別較(jiao)大；熱(re)(re)負(fu)荷(he)變(bian)化(hua)較(jiao)大：季節性熱(re)(re)負(fu)荷(he)占全年(nian)總負(fu)荷(he)比例較(jiao)大。
三、熱水熱力(li)網形式的確(que)定(ding)
熱(re)(re)水(shui)熱(re)(re)力網(wang)宜采用(yong)閉(bi)式(shi)雙管制(zhi)。以(yi)熱(re)(re)電廠(chang)為熱(re)(re)源的熱(re)(re)水(shui)熱(re)(re)力網(wang)，同時(shi)有(you)工(gong)藝、采暖、通風、空調、生(sheng)活熱(re)(re)水(shui)多種熱(re)(re)負(fu)荷，在生(sheng)產工(gong)藝熱(re)(re)負(fu)荷與采暖熱(re)(re)負(fu)荷所需供熱(re)(re)介質參數相差較(jiao)(jiao)大(da)，或(huo)季節性(xing)熱(re)(re)負(fu)荷占總(zong)熱(re)(re)負(fu)荷比例較(jiao)(jiao)大(da)，且技術經濟(ji)合(he)理(li)時(shi)，可采用(yong)閉(bi)式(shi)多管制(zhi)。
當熱(re)水(shui)熱(re)力網(wang)具有水(shui)處理費用(yong)較低的(de)豐富的(de)補(bu)給(gei)水(shui)資(zi)源，且技術經濟(ji)合理時，可采用(yong)開(kai)式熱(re)力網(wang)。
當熱(re)(re)水熱(re)(re)力網具(ju)有(you)與生活熱(re)(re)水熱(re)(re)負荷相適應的廉價(jia)低位能熱(re)(re)源，且技(ji)術經濟合理時，可采用開式熱(re)(re)水網。
開式熱(re)水熱(re)力網在生活(huo)熱(re)水熱(re)負荷足夠大(da)且技(ji)術(shu)經濟合(he)理時，可不設回水管。
四、蒸汽熱力網形式的確定
蒸(zheng)汽(qi)熱力(li)網(wang)宜采用(yong)單管制。當各用(yong)戶間所(suo)需蒸(zheng)汽(qi)參(can)數相差較(jiao)大(da)或季(ji)節性熱負(fu)荷(he)占總熱負(fu)荷(he)比例(li)較(jiao)大(da)且技術經濟合理時，蒸(zheng)汽(qi)熱力(li)網(wang)可采用(yong)雙管或多管制。
蒸汽(qi)熱(re)(re)力(li)網的熱(re)(re)負(fu)荷(he)分期增長時(shi)，可采用雙(shuang)管(guan)或多(duo)管(guan)制(zhi)。蒸汽(qi)供熱(re)(re)系(xi)統應創(chuang)造條(tiao)件采用間接換熱(re)(re)系(xi)統。當被加熱(re)(re)介質泄漏不會產生危害時(shi)，其凝(ning)(ning)結水(shui)應全部回收并設置凝(ning)(ning)結水(shui)管(guan)道。
當(dang)凝結(jie)水(shui)(shui)回收(shou)時，用戶熱力站應設閉(bi)式凝結(jie)水(shui)(shui)箱，用水(shui)(shui)泵將凝結(jie)水(shui)(shui)送回熱源(yuan)。
五(wu)、多供熱(re)源熱(re)力網形(xing)式的確定
供熱建筑面積大于1000×104㎡的供熱系統應采用多熱源供熱，且各熱源熱力干線應連通。在技術經濟合理時，熱力網干線可連接成環狀管網。對供熱可靠性有特殊要求的用戶，有條件時應由兩個熱源供熱，或者設自備熱源。
