一、供熱(re)系統與介質
集(ji)(ji)中供(gong)(gong)熱(re)(re)(re)(re)(re)系(xi)(xi)統(tong)(tong)(tong)(tong)(tong)是(shi)指一個(ge)或多(duo)個(ge)集(ji)(ji)中的(de)熱(re)(re)(re)(re)(re)源，通(tong)過(guo)供(gong)(gong)熱(re)(re)(re)(re)(re)管(guan)網(wang)向多(duo)個(ge)熱(re)(re)(re)(re)(re)用(yong)戶(hu)供(gong)(gong)應(ying)熱(re)(re)(re)(re)(re)能的(de)系(xi)(xi)統(tong)(tong)(tong)(tong)(tong)，它主要由熱(re)(re)(re)(re)(re)源、熱(re)(re)(re)(re)(re)網(wang)和熱(re)(re)(re)(re)(re)用(yong)戶(hu)組成。其(qi)中熱(re)(re)(re)(re)(re)源是(shi)指將天然(ran)或人造的(de)能源形態轉化為符合供(gong)(gong)熱(re)(re)(re)(re)(re)要求(qiu)的(de)熱(re)(re)(re)(re)(re)能裝置。熱(re)(re)(re)(re)(re)網(wang)是(shi)指由熱(re)(re)(re)(re)(re)源向熱(re)(re)(re)(re)(re)用(yong)戶(hu)輸送和分(fen)(fen)配供(gong)(gong)熱(re)(re)(re)(re)(re)介質的(de)管(guan)道(dao)系(xi)(xi)統(tong)(tong)(tong)(tong)(tong)，熱(re)(re)(re)(re)(re)用(yong)戶(hu)是(shi)指從(cong)熱(re)(re)(re)(re)(re)源獲(huo)得熱(re)(re)(re)(re)(re)能的(de)用(yong)熱(re)(re)(re)(re)(re)裝置。集(ji)(ji)中供(gong)(gong)熱(re)(re)(re)(re)(re)系(xi)(xi)統(tong)(tong)(tong)(tong)(tong)分(fen)(fen)類方(fang)式有三種，可以根(gen)據(ju)熱(re)(re)(re)(re)(re)源分(fen)(fen)類、根(gen)據(ju)熱(re)(re)(re)(re)(re)媒(mei)分(fen)(fen)類、根(gen)據(ju)供(gong)(gong)熱(re)(re)(re)(re)(re)管(guan)網(wang)分(fen)(fen)類。集(ji)(ji)中供(gong)(gong)熱(re)(re)(re)(re)(re)系(xi)(xi)統(tong)(tong)(tong)(tong)(tong)按熱(re)(re)(re)(re)(re)源形式的(de)不(bu)同可分(fen)(fen)為：熱(re)(re)(re)(re)(re)電廠供(gong)(gong)熱(re)(re)(re)(re)(re)系(xi)(xi)統(tong)(tong)(tong)(tong)(tong)、區域鍋爐房供(gong)(gong)熱(re)(re)(re)(re)(re)系(xi)(xi)統(tong)(tong)(tong)(tong)(tong)、地熱(re)(re)(re)(re)(re)供(gong)(gong)熱(re)(re)(re)(re)(re)系(xi)(xi)統(tong)(tong)(tong)(tong)(tong)、工業余熱(re)(re)(re)(re)(re)供(gong)(gong)熱(re)(re)(re)(re)(re)系(xi)(xi)統(tong)(tong)(tong)(tong)(tong)、核供(gong)(gong)熱(re)(re)(re)(re)(re)堆(dui)和太陽能供(gong)(gong)熱(re)(re)(re)(re)(re)系(xi)(xi)統(tong)(tong)(tong)(tong)(tong)等(deng)。集(ji)(ji)中供(gong)(gong)熱(re)(re)(re)(re)(re)系(xi)(xi)統(tong)(tong)(tong)(tong)(tong)根(gen)據(ju)熱(re)(re)(re)(re)(re)媒(mei)不(bu)同分(fen)(fen)為蒸(zheng)汽供(gong)(gong)熱(re)(re)(re)(re)(re)系(xi)(xi)統(tong)(tong)(tong)(tong)(tong)和熱(re)(re)(re)(re)(re)水供(gong)(gong)熱(re)(re)(re)(re)(re)系(xi)(xi)統(tong)(tong)(tong)(tong)(tong)。
熱(re)(re)水熱(re)(re)力網供熱(re)(re)介質設計(ji)壓(ya)力小于(yu)或等于(yu)2.5MPa，設計(ji)溫(wen)度小于(yu)或等于(yu)200℃；蒸汽熱(re)(re)力網供熱(re)(re)介質設計(ji)壓(ya)力小于(yu)或等于(yu)1.6MPa，設計(ji)溫(wen)度小于(yu)或等于(yu)350℃。
對民用建筑物采暖、通風、空調及生活熱(re)水(shui)(shui)熱(re)負荷供熱(re)的城市熱(re)力網，宜采用水(shui)(shui)作供熱(re)介質。
對生(sheng)(sheng)產(chan)(chan)工藝熱(re)(re)(re)負(fu)荷(he)和采(cai)(cai)暖、通風、空調、生(sheng)(sheng)活(huo)熱(re)(re)(re)水熱(re)(re)(re)負(fu)荷(he)供(gong)(gong)熱(re)(re)(re)的(de)城市熱(re)(re)(re)力網供(gong)(gong)熱(re)(re)(re)介質(zhi)按下列原則確定：當生(sheng)(sheng)產(chan)(chan)工藝熱(re)(re)(re)負(fu)荷(he)為主(zhu)要(yao)負(fu)荷(he)，且(qie)必須采(cai)(cai)用(yong)蒸汽供(gong)(gong)熱(re)(re)(re)時，宜(yi)采(cai)(cai)用(yong)蒸汽作供(gong)(gong)熱(re)(re)(re)介質(zhi)；當以水位供(gong)(gong)熱(re)(re)(re)介質(zhi)能夠(gou)滿(man)足(zu)生(sheng)(sheng)產(chan)(chan)工藝需要(yao)（包括在用(yong)戶處轉換為蒸汽），且(qie)技術(shu)經濟(ji)合理時，宜(yi)采(cai)(cai)用(yong)水作供(gong)(gong)熱(re)(re)(re)介質(zhi)；當采(cai)(cai)暖、通風、空調熱(re)(re)(re)負(fu)荷(he)為主(zhu)要(yao)負(fu)荷(he)，生(sheng)(sheng)產(chan)(chan)工藝又(you)必須采(cai)(cai)用(yong)蒸汽供(gong)(gong)熱(re)(re)(re)，經技術(shu)經濟(ji)比(bi)較認為合理時，可(ke)采(cai)(cai)用(yong)水和蒸汽兩種供(gong)(gong)熱(re)(re)(re)介質(zhi)。
1. 國家(jia)現(xian)行(xing)標(biao)準(zhun)GJJ／T 34《城鎮(zhen)供(gong)熱管(guan)(guan)網(wang)設(she)計(ji)(ji)(ji)(ji)規范》適用于(yu)(yu)供(gong)熱熱水介質設(she)計(ji)(ji)(ji)(ji)壓力(li)小于(yu)(yu)或等于(yu)(yu)2.5MPa，設(she)計(ji)(ji)(ji)(ji)溫(wen)度小于(yu)(yu)或等于(yu)(yu)200℃；供(gong)熱蒸汽(qi)介質設(she)計(ji)(ji)(ji)(ji)壓力(li)小于(yu)(yu)或等于(yu)(yu)1.6MPa，設(she)計(ji)(ji)(ji)(ji)溫(wen)度小于(yu)(yu)或等于(yu)(yu)350℃的(de)(de)下列城鎮(zhen)供(gong)熱管(guan)(guan)網(wang)的(de)(de)設(she)計(ji)(ji)(ji)(ji)：以熱電廠或鍋爐房為熱源，自熱切至建筑物熱力(li)人口的(de)(de)供(gong)熱管(guan)(guan)網(wang)，供(gong)熱管(guan)(guan)網(wang)新(xin)建、擴建或改建的(de)(de)管(guan)(guan)道、中斷泵站和熱力(li)站等工藝系(xi)統。
2. 國家現行(xing)標(biao)準GJJ／T 81《城鎮供熱(re)(re)直埋熱(re)(re)水(shui)管道(dao)技術規(gui)程》適用于(yu)(yu)新建(jian)、改建(jian)、擴建(jian)的設(she)計溫(wen)度小(xiao)于(yu)(yu)或(huo)等于(yu)(yu)150℃、設(she)計壓力小(xiao)于(yu)(yu)或(huo)等于(yu)(yu)2.5MPa，DN小(xiao)于(yu)(yu)或(huo)等于(yu)(yu)1200mm的城鎮供熱(re)(re)直埋熱(re)(re)水(shui)管道(dao)的設(she)計、施工(gong)、驗(yan)收和運行(xing)管理。
3. 國家現行標準GJJ／T 104《城鎮供熱直(zhi)埋蒸汽管道技(ji)術規程(cheng)》適用于工作壓力小于或等于2.5MPa，溫度小于或等于350℃，直(zhi)接埋地敷設(she)的(de)鋼質外護蒸汽保(bao)溫管道的(de)設(she)計、施工、驗收及運行維護。
二、熱力網的形(xing)式
供(gong)熱管網按其平(ping)面布置形式可(ke)分(fen)為枝狀管網、環(huan)狀管網和(he)多管制管網。其特點是(shi)：
1. 枝狀管網
從(cong)熱源引(yin)出主干(gan)線沿城鎮道路向各熱用(yong)戶(hu)供(gong)(gong)熱，形成類似樹枝狀(zhuang)的(de)(de)管(guan)(guan)(guan)網(wang)(wang)叫枝狀(zhuang)管(guan)(guan)(guan)網(wang)(wang)。枝狀(zhuang)管(guan)(guan)(guan)網(wang)(wang)是目前(qian)我國城鎮供(gong)(gong)熱中普遍(bian)采用(yong)的(de)(de)形式，它形式簡單、投資費(fei)用(yong)低，且運行(xing)管(guan)(guan)(guan)理(li)方便，但安全可靠性較(jiao)(jiao)(jiao)差(cha)，當管(guan)(guan)(guan)網(wang)(wang)中距離熱源較(jiao)(jiao)(jiao)近的(de)(de)主干(gan)線發生故障時，會影響較(jiao)(jiao)(jiao)多的(de)(de)熱用(yong)戶(hu)用(yong)熱。
2. 環狀(zhuang)管網
供(gong)熱管網的主干線(xian)之(zhi)間在(zai)適當位(wei)置(zhi)連通構成(cheng)環(huan)形，環(huan)狀管網運行(xing)較安全可靠(kao)，局部發生故障可通過(guo)環(huan)網供(gong)熱。但投資費用高。
3. 多管制管網
一般用(yong)于以下情況：不(bu)能(neng)間斷的熱(re)(re)用(yong)戶；供熱(re)(re)系統中(zhong)熱(re)(re)用(yong)戶所需介質參數(shu)差(cha)別(bie)較大(da)；熱(re)(re)負荷(he)變(bian)化(hua)較大(da)：季節性熱(re)(re)負荷(he)占全年(nian)總負荷(he)比例較大(da)。
三、熱(re)水熱(re)力網(wang)形(xing)式的確定
熱(re)(re)(re)(re)(re)(re)水熱(re)(re)(re)(re)(re)(re)力網宜采(cai)用閉式雙管制(zhi)。以熱(re)(re)(re)(re)(re)(re)電廠為熱(re)(re)(re)(re)(re)(re)源的熱(re)(re)(re)(re)(re)(re)水熱(re)(re)(re)(re)(re)(re)力網，同時(shi)有工藝、采(cai)暖、通風(feng)、空(kong)調、生(sheng)活(huo)熱(re)(re)(re)(re)(re)(re)水多(duo)種熱(re)(re)(re)(re)(re)(re)負(fu)荷(he)，在生(sheng)產(chan)工藝熱(re)(re)(re)(re)(re)(re)負(fu)荷(he)與采(cai)暖熱(re)(re)(re)(re)(re)(re)負(fu)荷(he)所需(xu)供熱(re)(re)(re)(re)(re)(re)介質參數相差較大(da)，或季節(jie)性熱(re)(re)(re)(re)(re)(re)負(fu)荷(he)占總熱(re)(re)(re)(re)(re)(re)負(fu)荷(he)比例較大(da)，且技術經濟合理時(shi)，可(ke)采(cai)用閉式多(duo)管制(zhi)。
當(dang)熱水熱力網(wang)具有水處理費(fei)用(yong)較(jiao)低的(de)豐富的(de)補給水資源(yuan)，且技術經濟(ji)合理時，可采用(yong)開式(shi)熱力網(wang)。
當(dang)熱水(shui)熱力(li)網具有與生活熱水(shui)熱負荷相適應的(de)廉(lian)價低位能熱源，且技術經(jing)濟(ji)合理時，可采用(yong)開式熱水(shui)網。
開式熱(re)水(shui)熱(re)力網(wang)在生活熱(re)水(shui)熱(re)負荷足夠大且技術經濟合理(li)時，可不設回水(shui)管。
四(si)、蒸汽(qi)熱力網形式的確定(ding)
蒸汽熱力(li)網宜采(cai)(cai)用(yong)單(dan)管制。當各(ge)用(yong)戶間所需(xu)蒸汽參數相差較(jiao)大或季節性熱負荷(he)占總熱負荷(he)比例較(jiao)大且(qie)技術經濟合理時(shi)，蒸汽熱力(li)網可(ke)采(cai)(cai)用(yong)雙管或多管制。
蒸汽熱(re)力網(wang)的熱(re)負荷分期(qi)增長時，可(ke)采用雙管(guan)或多管(guan)制。蒸汽供熱(re)系(xi)統應(ying)創造條件采用間接(jie)換熱(re)系(xi)統。當被加熱(re)介質泄漏(lou)不會產(chan)生危害(hai)時，其(qi)凝結(jie)水應(ying)全部回收并(bing)設置(zhi)凝結(jie)水管(guan)道。
當凝(ning)(ning)結水回收時(shi)，用戶(hu)熱力站應設閉式凝(ning)(ning)結水箱，用水泵將凝(ning)(ning)結水送回熱源(yuan)。
五(wu)、多供熱(re)源(yuan)熱(re)力網形式(shi)的確(que)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。
