一(yi)、供(gong)熱系統與介質(zhi)
集中供(gong)(gong)熱(re)(re)(re)(re)(re)(re)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)是(shi)指(zhi)一個或多個集中的(de)(de)(de)熱(re)(re)(re)(re)(re)(re)源，通過(guo)供(gong)(gong)熱(re)(re)(re)(re)(re)(re)管(guan)網(wang)向多個熱(re)(re)(re)(re)(re)(re)用戶供(gong)(gong)應熱(re)(re)(re)(re)(re)(re)能(neng)的(de)(de)(de)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)，它主要(yao)(yao)由(you)熱(re)(re)(re)(re)(re)(re)源、熱(re)(re)(re)(re)(re)(re)網(wang)和熱(re)(re)(re)(re)(re)(re)用戶組(zu)成。其中熱(re)(re)(re)(re)(re)(re)源是(shi)指(zhi)將天然或人造的(de)(de)(de)能(neng)源形(xing)態轉化為(wei)符合供(gong)(gong)熱(re)(re)(re)(re)(re)(re)要(yao)(yao)求的(de)(de)(de)熱(re)(re)(re)(re)(re)(re)能(neng)裝置(zhi)。熱(re)(re)(re)(re)(re)(re)網(wang)是(shi)指(zhi)由(you)熱(re)(re)(re)(re)(re)(re)源向熱(re)(re)(re)(re)(re)(re)用戶輸送和分(fen)(fen)配供(gong)(gong)熱(re)(re)(re)(re)(re)(re)介(jie)質的(de)(de)(de)管(guan)道(dao)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)，熱(re)(re)(re)(re)(re)(re)用戶是(shi)指(zhi)從熱(re)(re)(re)(re)(re)(re)源獲(huo)得熱(re)(re)(re)(re)(re)(re)能(neng)的(de)(de)(de)用熱(re)(re)(re)(re)(re)(re)裝置(zhi)。集中供(gong)(gong)熱(re)(re)(re)(re)(re)(re)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)分(fen)(fen)類方(fang)式有(you)三種，可以(yi)根據(ju)熱(re)(re)(re)(re)(re)(re)源分(fen)(fen)類、根據(ju)熱(re)(re)(re)(re)(re)(re)媒(mei)(mei)分(fen)(fen)類、根據(ju)供(gong)(gong)熱(re)(re)(re)(re)(re)(re)管(guan)網(wang)分(fen)(fen)類。集中供(gong)(gong)熱(re)(re)(re)(re)(re)(re)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)按(an)熱(re)(re)(re)(re)(re)(re)源形(xing)式的(de)(de)(de)不同(tong)可分(fen)(fen)為(wei)：熱(re)(re)(re)(re)(re)(re)電廠供(gong)(gong)熱(re)(re)(re)(re)(re)(re)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)、區域鍋(guo)爐房供(gong)(gong)熱(re)(re)(re)(re)(re)(re)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)、地熱(re)(re)(re)(re)(re)(re)供(gong)(gong)熱(re)(re)(re)(re)(re)(re)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)、工(gong)業(ye)余熱(re)(re)(re)(re)(re)(re)供(gong)(gong)熱(re)(re)(re)(re)(re)(re)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)、核供(gong)(gong)熱(re)(re)(re)(re)(re)(re)堆(dui)和太陽能(neng)供(gong)(gong)熱(re)(re)(re)(re)(re)(re)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)等。集中供(gong)(gong)熱(re)(re)(re)(re)(re)(re)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)根據(ju)熱(re)(re)(re)(re)(re)(re)媒(mei)(mei)不同(tong)分(fen)(fen)為(wei)蒸汽供(gong)(gong)熱(re)(re)(re)(re)(re)(re)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)和熱(re)(re)(re)(re)(re)(re)水供(gong)(gong)熱(re)(re)(re)(re)(re)(re)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)。
熱(re)水熱(re)力(li)(li)網供(gong)(gong)熱(re)介質設(she)計(ji)壓力(li)(li)小(xiao)(xiao)于(yu)或等(deng)于(yu)2.5MPa，設(she)計(ji)溫(wen)度小(xiao)(xiao)于(yu)或等(deng)于(yu)200℃；蒸汽熱(re)力(li)(li)網供(gong)(gong)熱(re)介質設(she)計(ji)壓力(li)(li)小(xiao)(xiao)于(yu)或等(deng)于(yu)1.6MPa，設(she)計(ji)溫(wen)度小(xiao)(xiao)于(yu)或等(deng)于(yu)350℃。
對民用(yong)建筑物(wu)采暖(nuan)、通風、空調及(ji)生(sheng)活熱(re)水(shui)熱(re)負荷(he)供熱(re)的城市(shi)熱(re)力網(wang)，宜采用(yong)水(shui)作供熱(re)介(jie)質。
對生產工(gong)藝(yi)熱(re)(re)(re)(re)負(fu)荷(he)(he)和采暖(nuan)、通風、空調(diao)、生活(huo)熱(re)(re)(re)(re)水熱(re)(re)(re)(re)負(fu)荷(he)(he)供(gong)(gong)(gong)(gong)熱(re)(re)(re)(re)的城市熱(re)(re)(re)(re)力網供(gong)(gong)(gong)(gong)熱(re)(re)(re)(re)介(jie)質(zhi)按下列原(yuan)則(ze)確定(ding)：當生產工(gong)藝(yi)熱(re)(re)(re)(re)負(fu)荷(he)(he)為(wei)主要負(fu)荷(he)(he)，且必(bi)須采用(yong)蒸(zheng)(zheng)汽供(gong)(gong)(gong)(gong)熱(re)(re)(re)(re)時(shi)，宜(yi)采用(yong)蒸(zheng)(zheng)汽作供(gong)(gong)(gong)(gong)熱(re)(re)(re)(re)介(jie)質(zhi)；當以水位供(gong)(gong)(gong)(gong)熱(re)(re)(re)(re)介(jie)質(zhi)能夠滿足生產工(gong)藝(yi)需要（包括在用(yong)戶處轉換(huan)為(wei)蒸(zheng)(zheng)汽），且技術(shu)經(jing)(jing)濟合理(li)時(shi)，宜(yi)采用(yong)水作供(gong)(gong)(gong)(gong)熱(re)(re)(re)(re)介(jie)質(zhi)；當采暖(nuan)、通風、空調(diao)熱(re)(re)(re)(re)負(fu)荷(he)(he)為(wei)主要負(fu)荷(he)(he)，生產工(gong)藝(yi)又(you)必(bi)須采用(yong)蒸(zheng)(zheng)汽供(gong)(gong)(gong)(gong)熱(re)(re)(re)(re)，經(jing)(jing)技術(shu)經(jing)(jing)濟比較認為(wei)合理(li)時(shi)，可采用(yong)水和蒸(zheng)(zheng)汽兩種(zhong)供(gong)(gong)(gong)(gong)熱(re)(re)(re)(re)介(jie)質(zhi)。
1. 國家現(xian)行標準(zhun)GJJ／T 34《城鎮供(gong)熱(re)(re)(re)管(guan)網設(she)計(ji)規范》適(shi)用于(yu)(yu)供(gong)熱(re)(re)(re)熱(re)(re)(re)水(shui)介質(zhi)設(she)計(ji)壓力(li)小(xiao)(xiao)(xiao)于(yu)(yu)或等(deng)于(yu)(yu)2.5MPa，設(she)計(ji)溫(wen)度小(xiao)(xiao)(xiao)于(yu)(yu)或等(deng)于(yu)(yu)200℃；供(gong)熱(re)(re)(re)蒸汽介質(zhi)設(she)計(ji)壓力(li)小(xiao)(xiao)(xiao)于(yu)(yu)或等(deng)于(yu)(yu)1.6MPa，設(she)計(ji)溫(wen)度小(xiao)(xiao)(xiao)于(yu)(yu)或等(deng)于(yu)(yu)350℃的(de)下列城鎮供(gong)熱(re)(re)(re)管(guan)網的(de)設(she)計(ji)：以熱(re)(re)(re)電(dian)廠或鍋(guo)爐(lu)房為(wei)熱(re)(re)(re)源(yuan)，自熱(re)(re)(re)切至建(jian)筑物熱(re)(re)(re)力(li)人口的(de)供(gong)熱(re)(re)(re)管(guan)網，供(gong)熱(re)(re)(re)管(guan)網新建(jian)、擴建(jian)或改建(jian)的(de)管(guan)道、中斷泵站和熱(re)(re)(re)力(li)站等(deng)工藝系(xi)統(tong)。
2. 國家現行標(biao)準GJJ／T 81《城鎮(zhen)供熱直埋(mai)熱水管道(dao)技術規程》適用于(yu)(yu)新建、改建、擴建的設(she)計溫度小(xiao)于(yu)(yu)或(huo)等(deng)(deng)于(yu)(yu)150℃、設(she)計壓力小(xiao)于(yu)(yu)或(huo)等(deng)(deng)于(yu)(yu)2.5MPa，DN小(xiao)于(yu)(yu)或(huo)等(deng)(deng)于(yu)(yu)1200mm的城鎮(zhen)供熱直埋(mai)熱水管道(dao)的設(she)計、施(shi)工、驗收和(he)運(yun)行管理(li)。
3. 國家現行標(biao)準GJJ／T 104《城鎮供熱(re)直(zhi)埋蒸汽管道技術規(gui)程》適用于(yu)(yu)工作壓力小于(yu)(yu)或等于(yu)(yu)2.5MPa，溫(wen)度小于(yu)(yu)或等于(yu)(yu)350℃，直(zhi)接埋地敷設的(de)鋼質外護蒸汽保溫(wen)管道的(de)設計、施工、驗收及運(yun)行維(wei)護。
二(er)、熱力網的形(xing)式
供熱管(guan)網按其(qi)平面布置形式可分為枝(zhi)狀管(guan)網、環狀管(guan)網和多(duo)管(guan)制管(guan)網。其(qi)特點是：
1. 枝狀(zhuang)管網
從(cong)熱(re)源引(yin)出主干線沿城鎮道路向各熱(re)用戶供熱(re)，形(xing)成類(lei)似樹(shu)枝(zhi)狀的管(guan)網叫枝(zhi)狀管(guan)網。枝(zhi)狀管(guan)網是目(mu)前(qian)我國(guo)城鎮供熱(re)中普遍采用的形(xing)式(shi)，它(ta)形(xing)式(shi)簡單、投資費用低，且(qie)運行管(guan)理(li)方便，但安(an)全可靠性較(jiao)差，當管(guan)網中距(ju)離(li)熱(re)源較(jiao)近的主干線發(fa)生故(gu)障時，會影響較(jiao)多的熱(re)用戶用熱(re)。
2. 環(huan)狀管網
供(gong)(gong)熱管網的主干線之(zhi)間在適(shi)當位(wei)置連(lian)通(tong)(tong)構成環形(xing)，環狀管網運行較安全可靠，局部發生故障可通(tong)(tong)過環網供(gong)(gong)熱。但投資費用高(gao)。
3. 多管(guan)制管(guan)網
一(yi)般(ban)用(yong)于(yu)以下情況：不能(neng)間(jian)斷的熱(re)用(yong)戶；供熱(re)系統中熱(re)用(yong)戶所(suo)需介質參數差別(bie)較大(da)；熱(re)負荷(he)變化較大(da)：季節性熱(re)負荷(he)占全年總負荷(he)比例較大(da)。
三(san)、熱(re)水(shui)熱(re)力網形式的(de)確(que)定
熱(re)水熱(re)力網宜(yi)采(cai)(cai)用閉式雙管(guan)制。以(yi)熱(re)電廠為熱(re)源的熱(re)水熱(re)力網，同(tong)時(shi)有(you)工藝、采(cai)(cai)暖、通風、空調、生(sheng)活熱(re)水多種熱(re)負荷(he)，在生(sheng)產工藝熱(re)負荷(he)與采(cai)(cai)暖熱(re)負荷(he)所需供熱(re)介質參(can)數相(xiang)差較(jiao)大，或季節性(xing)熱(re)負荷(he)占(zhan)總熱(re)負荷(he)比例較(jiao)大，且(qie)技術經濟合理時(shi)，可(ke)采(cai)(cai)用閉式多管(guan)制。
當熱水(shui)熱力網具有水(shui)處理費(fei)用(yong)較低的豐(feng)富的補給(gei)水(shui)資源(yuan)，且(qie)技術經濟合理時，可采用(yong)開(kai)式熱力網。
當熱(re)水熱(re)力網具有與(yu)生(sheng)活熱(re)水熱(re)負荷(he)相適(shi)應的(de)廉價低位能熱(re)源，且技術經(jing)濟合(he)理(li)時，可采用開式熱(re)水網。
開式熱(re)水(shui)熱(re)力網在生活熱(re)水(shui)熱(re)負荷足夠(gou)大(da)且(qie)技術(shu)經(jing)濟(ji)合理時，可不(bu)設回水(shui)管。
四、蒸(zheng)汽熱力網(wang)形(xing)式的確定
蒸汽(qi)熱力網(wang)宜采(cai)用單管(guan)(guan)制。當各用戶間所需(xu)蒸汽(qi)參數相差較(jiao)大或季節(jie)性熱負荷占總熱負荷比例較(jiao)大且技(ji)術經濟合(he)理(li)時，蒸汽(qi)熱力網(wang)可采(cai)用雙管(guan)(guan)或多(duo)管(guan)(guan)制。
蒸汽(qi)熱(re)力(li)網的熱(re)負荷分期增(zeng)長時(shi)，可采(cai)用雙管(guan)(guan)或多管(guan)(guan)制。蒸汽(qi)供熱(re)系統應創造條件采(cai)用間接換熱(re)系統。當被加熱(re)介質泄漏不會產(chan)生危害時(shi)，其凝(ning)結水(shui)(shui)應全部回收(shou)并設置凝(ning)結水(shui)(shui)管(guan)(guan)道。
當凝結水(shui)(shui)回(hui)收(shou)時，用戶(hu)熱力站應設(she)閉式凝結水(shui)(shui)箱，用水(shui)(shui)泵將凝結水(shui)(shui)送回(hui)熱源(yuan)。
五、多供熱源熱力網形式的(de)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。
