王 陽(yáng),李保明,3※
(1.中國(guó)農(nóng)業(yè)大學(xué)農(nóng)業(yè)部設(shè)施農(nóng)業(yè)工程重點(diǎn)實(shí)驗(yàn)室,北京 100083; 2.中國(guó)農(nóng)業(yè)大學(xué)水利與土木工程學(xué)院,北京 100083;3.北京市畜禽健康養(yǎng)殖環(huán)境工程技術(shù)研究中心,北京 100083)
密閉式蛋雞舍外圍護(hù)結(jié)構(gòu)冬季保溫性能分析與試驗(yàn)
王 陽(yáng)1,2,李保明1,2,3※
(1.中國(guó)農(nóng)業(yè)大學(xué)農(nóng)業(yè)部設(shè)施農(nóng)業(yè)工程重點(diǎn)實(shí)驗(yàn)室,北京 100083; 2.中國(guó)農(nóng)業(yè)大學(xué)水利與土木工程學(xué)院,北京 100083;3.北京市畜禽健康養(yǎng)殖環(huán)境工程技術(shù)研究中心,北京 100083)
蛋雞舍圍護(hù)結(jié)構(gòu)的保溫隔熱性能是影響雞舍溫度的穩(wěn)定性,進(jìn)而影響蛋雞健康和生產(chǎn)性能的關(guān)鍵因素。由于蛋雞舍一般不采暖,依靠蛋雞的自身顯熱產(chǎn)熱量來(lái)維持冬季蛋雞舍內(nèi)溫度,因此如果蛋雞舍冬季飼養(yǎng)密度較低、通風(fēng)過(guò)度或圍護(hù)結(jié)構(gòu)保溫性能不足,都難以滿足蛋雞舍溫度環(huán)境的要求。如何確定不同氣候區(qū)雞舍圍護(hù)結(jié)構(gòu)必要的保溫性能和飼養(yǎng)密度要求是解決蛋雞舍冬季通風(fēng)和保溫矛盾問(wèn)題的關(guān)鍵。該文通過(guò)建立蛋雞舍動(dòng)態(tài)熱平衡理論模型,系統(tǒng)分析了不同氣候區(qū)雞舍圍護(hù)結(jié)構(gòu)的最低熱阻需求,得出不同氣候區(qū)雞舍圍護(hù)結(jié)構(gòu)的保溫性能要求與蛋雞飼養(yǎng)方式(密度)的關(guān)系。結(jié)果表明:冬季舍外計(jì)算溫度分別為?25 ℃(東北、內(nèi)蒙古)、?15 ℃(華北、西北)、0 ℃(長(zhǎng)江以南)的地區(qū),蛋雞舍墻體、屋面的最小熱阻應(yīng)分別不小于0.778、0.972;0.573、0.716;0.266、0.333(m2·℃)/W;對(duì)應(yīng)3層全階梯籠養(yǎng)、4層半階梯籠養(yǎng)和4層疊層、6層疊層、8層疊層籠養(yǎng)等飼養(yǎng)模式最大飼養(yǎng)密度下,所能夠適應(yīng)的圍護(hù)結(jié)構(gòu)冬季室外計(jì)算溫度應(yīng)分別不低于?14、?17、?19、?22、?23 ℃。研究結(jié)果為不同氣候地區(qū)選擇適宜飼養(yǎng)模式以及密閉式蛋雞舍圍護(hù)結(jié)構(gòu)保溫系統(tǒng)的設(shè)計(jì)提供了理論依據(jù)。
設(shè)施;保溫;熱阻;環(huán)境控制;密閉式蛋雞舍;圍護(hù)結(jié)構(gòu);耗熱量;飼養(yǎng)密度
王 陽(yáng),李保明. 密閉式蛋雞舍外圍護(hù)結(jié)構(gòu)冬季保溫性能分析與試驗(yàn)[J]. 農(nóng)業(yè)工程學(xué)報(bào),2017,33(7):190-196.doi:10.11975/j.issn.1002-6819.2017.07.025 http://www.tcsae.org
Wang Yang, Li Baoming. Analysis and experiment on thermal insulation performance of outer building envelope for closed layer house in winter[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2017, 33(7): 190-196. (in Chinese with English abstract)doi:10.11975/j.issn.1002-6819.2017.07.025 http://www.tcsae.org
北方寒冷地區(qū)蛋雞在冬季常因舍內(nèi)溫度過(guò)低而導(dǎo)致產(chǎn)蛋率減少5%~10%、飼料消耗提高3~5 g/(d·只)[1-5]。蛋雞舍一般無(wú)采暖系統(tǒng)供熱,依靠雞群自身的顯熱產(chǎn)熱量來(lái)維持舍內(nèi)必要的溫度水平,雞舍圍護(hù)結(jié)構(gòu)的保溫隔熱性能是影響雞舍內(nèi)溫度穩(wěn)定的關(guān)鍵因素[6-7]。由于蛋雞舍冬季也必須提供必要的新鮮空氣和排除有害氣體[8],蛋雞舍冬季通風(fēng)耗熱是主要熱損耗。因此,不同氣候地區(qū)、不同類(lèi)型蛋雞舍圍護(hù)結(jié)構(gòu)具有良好的保溫隔熱性能,有助于協(xié)調(diào)蛋雞舍冬季通風(fēng)與保溫的矛盾,確保維持雞舍內(nèi)溫度的穩(wěn)定性。
近年來(lái),針對(duì)蛋雞的產(chǎn)熱量和蛋雞舍冬季最小通風(fēng)量的取值問(wèn)題已開(kāi)展了一系列的理論和試驗(yàn)研究[9-15]。Chepete等[13]對(duì)蛋雞產(chǎn)熱量與蛋雞質(zhì)量的關(guān)系進(jìn)行了回歸分析,得出了產(chǎn)熱量與蛋雞體質(zhì)量的關(guān)系式;Chepete等[12,16]對(duì)冬季蛋雞舍最小通風(fēng)量進(jìn)行了研究分析,得出了傳送帶自動(dòng)干清糞系統(tǒng)可排除蛋雞舍有害氣體、滿足通風(fēng)換氣需求的最小通風(fēng)量。謝明文等[17]研究表明發(fā)現(xiàn),沈陽(yáng)地區(qū)雞場(chǎng)外圍護(hù)結(jié)構(gòu)總熱阻,遠(yuǎn)遠(yuǎn)小于沈陽(yáng)地區(qū)冬季低限熱阻值,雞舍保溫隔熱性能較差。中國(guó)不同氣候地區(qū)如何優(yōu)化確定蛋雞舍圍護(hù)結(jié)構(gòu)的保溫隔熱性能及飼養(yǎng)密度問(wèn)題仍然缺少設(shè)計(jì)依據(jù)[18],導(dǎo)致對(duì)蛋雞舍圍護(hù)結(jié)構(gòu)設(shè)計(jì)建設(shè)的隨意性和不合理性。中國(guó)不同氣候地區(qū)、不同類(lèi)型蛋雞舍的圍護(hù)結(jié)構(gòu)保溫隔熱性能設(shè)計(jì)參數(shù)方面缺乏相關(guān)研究。
本文通過(guò)分析不同氣候地區(qū)蛋雞舍外圍護(hù)結(jié)構(gòu)的最低熱阻要求,根據(jù)能量和質(zhì)量守恒定律,建立密閉式蛋雞舍熱平衡模型,得出不同氣候地區(qū)、不同類(lèi)型密閉式傳送帶清糞蛋雞舍的保溫性能要求及其與雞群飼養(yǎng)密度的影響關(guān)系。在滿足蛋雞群冬季舍內(nèi)環(huán)境的前提下,為降低能耗、節(jié)約成本以及蛋雞舍圍護(hù)結(jié)構(gòu)保溫系統(tǒng)的設(shè)計(jì)提供理論依據(jù)。
1.1 雞舍熱平衡模型建立
蛋雞舍的熱平衡是為維持雞舍空氣溫度的相對(duì)穩(wěn)定,保持其輸入和輸出雞舍的熱量之間的動(dòng)態(tài)平衡。蛋雞舍熱量損耗主要包括外圍護(hù)結(jié)構(gòu)散熱、通風(fēng)耗熱等,蛋雞群的顯熱產(chǎn)熱量是蛋雞舍主要得熱。為維持蛋雞舍內(nèi)動(dòng)態(tài)熱平衡,根據(jù)蛋雞舍的熱量平衡原理,建立如下數(shù)學(xué)模型

式中Qs為蛋雞群顯熱產(chǎn)熱量,W;Qm為設(shè)備(電機(jī)與照明等)發(fā)熱量,因夜間無(wú)照明等此值可忽略不計(jì),W;Qw為圍護(hù)結(jié)構(gòu)(墻、地面、屋頂?shù)龋﹤鳠岷臒崃浚琖;Qv為通風(fēng)換氣的熱損失,W。

式中A為雞舍外圍護(hù)結(jié)構(gòu)面積,m2;K為雞舍外圍護(hù)結(jié)構(gòu)的傳熱系數(shù),W/(m2·℃);ti為冬季舍內(nèi)計(jì)算溫度,℃;t0為供暖舍外計(jì)算溫度,℃;公式(2)為《實(shí)用供熱空調(diào)設(shè)計(jì)手冊(cè)》[19]推薦的熱負(fù)荷計(jì)算式。

式中Ro,min為外圍護(hù)結(jié)構(gòu)最小傳熱阻,(m2·℃)/W;Δty為室內(nèi)計(jì)算溫度與圍護(hù)結(jié)構(gòu)內(nèi)表面溫度的允許差值,℃,取值參照《民用建筑熱工設(shè)計(jì)規(guī)范》[20];Rn為圍護(hù)結(jié)構(gòu)內(nèi)表面換熱阻,(m2·℃)/W;公式(3)為《民用建筑熱工設(shè)計(jì)規(guī)范》[20]推薦的圍護(hù)結(jié)構(gòu)最小熱阻計(jì)算式。

式中v為每只雞的冬季最小通風(fēng)量,m3/(h·只);n為蛋雞飼養(yǎng)密度,只/m2;ρw為舍外溫度下的空氣密度,通風(fēng)量按進(jìn)氣量計(jì)算時(shí)取ρw=353/(t0+273),kg/m3;Cp為干空氣的定壓質(zhì)量比熱,Cp=1.0056 kJ/(kg·℃);0.278為單位換算系數(shù),1 kJ/h= 0.278 W;公式(4)為《實(shí)用供熱空調(diào)設(shè)計(jì)手冊(cè)》[19]推薦的熱負(fù)荷計(jì)算式。

式中Qt為雞群總產(chǎn)熱量,W;式(5)、式(6)為CIGR[21]推薦的蛋雞產(chǎn)熱量計(jì)算公式。
1.2 雞舍熱平衡計(jì)算分析簡(jiǎn)化
由式(1)可知,影響蛋雞舍內(nèi)溫?zé)岘h(huán)境的主要因素是圍護(hù)結(jié)構(gòu)傳熱散熱量和通風(fēng)熱損失。蛋雞舍建筑外圍護(hù)結(jié)構(gòu)材料實(shí)際的傳熱過(guò)程是較為復(fù)雜的,受接觸熱阻、流動(dòng)空氣間層、屋頂坡度等的影響,為簡(jiǎn)化起見(jiàn),本文分析中忽略這部分影響,將外圍護(hù)結(jié)構(gòu)視為均質(zhì)多層材料相同條件下的傳熱,蛋雞舍圍護(hù)結(jié)構(gòu)表面的換熱過(guò)程為熱傳導(dǎo)、輻射和對(duì)流的綜合影響,蛋雞舍外表面換熱是由于風(fēng)力作用產(chǎn)生的強(qiáng)迫對(duì)流換熱,內(nèi)表面的換熱是壁面與鄰近空氣和其他壁面由于溫差引起的自然對(duì)流和輻射換熱作用。中國(guó)蛋雞舍建筑地面一般為普通貼土非保溫水泥地面,組成地面的各層材料導(dǎo)熱系數(shù)都大于1.16 W/(m2·℃),此模型研究分析中非保溫地面?zhèn)鳠嵯禂?shù)按照最不利條件下傳熱系數(shù) 0.47 W/(m2·℃)分析研究簡(jiǎn)化。
溫、濕度是影響蛋雞健康和生產(chǎn)水平的主要溫?zé)嵋蛩亍Q芯勘砻鞯半u18周齡后的質(zhì)量約為1.5 kg[13],產(chǎn)蛋雞的適宜溫度為 13~27 ℃,適宜的相對(duì)濕度為 60%~ 65%,蛋雞舍溫度下限控制在13 ℃[22],蛋雞的產(chǎn)蛋性能及飼料轉(zhuǎn)化率相對(duì)較好。由上述條件,式(1)簡(jiǎn)化為

蛋雞舍冬季通風(fēng)主要為排除多余有害氣體,滿足通風(fēng)換氣的要求。由于傳送帶干清糞系統(tǒng)和乳頭式飲水器的普遍應(yīng)用,舍內(nèi)濕度和有害氣體濃度較傳統(tǒng)的刮板清糞系統(tǒng)等明顯減小。Chai等[16]通過(guò)連續(xù)2a的試驗(yàn)確定了蛋雞舍滿足通風(fēng)換氣的傳送帶干清糞蛋雞舍冬季最小通風(fēng)量;Pedersen等[15]對(duì)用 CO2確定畜禽場(chǎng)冬季通風(fēng)量進(jìn)行了評(píng)估;Li等[10]研究CO2濃度平衡確定的蛋雞舍冬季最小通風(fēng)量為0.43 m3/(h·只)。本文主要考慮分析傳送帶干清糞、乳頭式飲水器系統(tǒng)蛋雞舍,冬季最小通風(fēng)量取Li等[10]試驗(yàn)研究結(jié)果,此簡(jiǎn)化取值與美國(guó)[23]對(duì)不同品種單個(gè)畜禽的推薦通風(fēng)量和Chai等[16]研究的冬季最小通風(fēng)量基本一致。不同氣候區(qū)雞舍圍護(hù)結(jié)構(gòu)必要的保溫性能和飼養(yǎng)密度要求之間的關(guān)系式模型(7)可簡(jiǎn)化為

2.1 不同氣候地區(qū)蛋雞舍外圍護(hù)結(jié)構(gòu)最小熱阻
蛋雞舍各部分圍護(hù)結(jié)構(gòu)換熱的熱損耗多少與蛋雞舍建筑材料的熱阻有直接關(guān)系,實(shí)際生產(chǎn)過(guò)程中,在蛋雞舍室內(nèi)外溫差波動(dòng)的作用下,滿足圍護(hù)結(jié)構(gòu)內(nèi)表面不結(jié)露和防止內(nèi)表面溫度過(guò)低是保證蛋雞舍內(nèi)小環(huán)境穩(wěn)定的前提,內(nèi)表面結(jié)露可導(dǎo)致耗熱量增大和使圍護(hù)結(jié)構(gòu)易于損壞等,內(nèi)表面溫度過(guò)低將會(huì)對(duì)畜禽產(chǎn)生不良的冷輻射作用,因此,應(yīng)根據(jù)不同氣候地區(qū)保溫要求,合理選擇蛋雞舍建筑保溫材料,滿足最低傳熱阻要求。
劉以連等[24]將中國(guó)畜禽舍分為 3個(gè)區(qū)域(寒冷區(qū)<?10 ℃、溫暖區(qū)0~?10 ℃、炎熱區(qū)>0 ℃),并根據(jù)日本不同氣候區(qū)的熱阻值,給出了中國(guó) 3個(gè)區(qū)域的最小熱阻值;張岫云等[25]據(jù)美國(guó)大荷蘭人養(yǎng)雞公司資料介紹,根據(jù)1月份平均氣溫,得出了3個(gè)區(qū)域(<?10、0~?10、>0 ℃)圍護(hù)結(jié)構(gòu)冬季低限熱阻值以及美國(guó)各個(gè)氣候區(qū)域中雞舍圍護(hù)結(jié)構(gòu)材料的選用,并將中國(guó)雞舍建筑分為五大氣候區(qū)域,為蛋雞舍外圍護(hù)結(jié)構(gòu)的選擇及雞舍構(gòu)造改造提供了參考依據(jù)。但中國(guó)氣候類(lèi)型多樣,蛋雞舍建筑類(lèi)型也呈現(xiàn)多樣化,蛋雞舍內(nèi)微環(huán)境很容易受外界氣候條件的影響。雞舍建筑相同氣候區(qū)域內(nèi)不同地區(qū)下,冬季室外計(jì)算溫度不同且溫度差別較大,但是相同氣候區(qū)域內(nèi)溫度不同的地區(qū)具有相同的最低熱阻值,容易造成雞舍建筑材料選擇不合理,不利于節(jié)約建筑材料以及降低成本;蛋雞舍冬季舍外計(jì)算溫度采用建筑熱工設(shè)計(jì)參數(shù)規(guī)定的不同地區(qū)圍護(hù)結(jié)構(gòu)冬季采暖室外計(jì)算溫度,更利于實(shí)現(xiàn)舍內(nèi)外溫差波動(dòng)較大時(shí),蛋雞舍內(nèi)微環(huán)境的相對(duì)穩(wěn)定。
根據(jù)《實(shí)用供熱空調(diào)設(shè)計(jì)手冊(cè)》[19]、《民用建筑熱工設(shè)計(jì)規(guī)范》[20]提出的建筑熱工分區(qū)及設(shè)計(jì)要求,外圍

表1 部分城市圍護(hù)結(jié)構(gòu)冬季室外計(jì)算溫度[19-20]Table1 Outdoor design conditions of temperature for outer building envelope of different cities in winter℃
2.2 不同氣候地區(qū)蛋雞舍外圍護(hù)結(jié)構(gòu)保溫性能要求
蛋雞舍圍護(hù)結(jié)構(gòu)的保溫隔熱性能影響雞舍內(nèi)微環(huán)境,然而蛋雞舍內(nèi)微環(huán)境的穩(wěn)定性是提高蛋雞健康及生產(chǎn)性能的關(guān)鍵因素,密閉式蛋雞舍圍護(hù)結(jié)構(gòu)的保溫性是維持蛋雞舍溫度穩(wěn)定的前提。不同氣候地區(qū),不同飼養(yǎng)方式對(duì)蛋雞舍建筑設(shè)計(jì)圍護(hù)結(jié)構(gòu)的保溫要求不同,無(wú)采暖系統(tǒng)供熱蛋雞舍建筑設(shè)計(jì)選用適宜密度、厚度的圍護(hù)結(jié)構(gòu)材料[26-27]及蛋雞群飼養(yǎng)方式(飼養(yǎng)密度),控制蛋雞舍動(dòng)態(tài)熱平衡[28],不僅能為蛋雞提供穩(wěn)定的小環(huán)境,實(shí)現(xiàn)雞舍內(nèi)溫度下限不低于13 ℃[22],而且可以降低生產(chǎn)成本,減少建筑圍護(hù)結(jié)構(gòu)材料的浪費(fèi)。

表2 不同地區(qū)蛋雞舍外圍護(hù)結(jié)構(gòu)冬季低限熱阻值Table2 Minimum recommended resistance of heat transfer for outer building envelope of layer house in different cities m2··W℃ -1
中國(guó)絕大多數(shù)蛋雞采用全程籠養(yǎng)工藝模式,主要有全階梯籠養(yǎng)、半階梯籠養(yǎng)和疊層籠養(yǎng)(4層、6層、8層)等集約化飼養(yǎng)方式,國(guó)內(nèi)學(xué)者研究表明[28-32]:3層全階梯籠養(yǎng)、4層半階梯籠養(yǎng)、4層疊層籠養(yǎng)、6層疊層籠養(yǎng)、8層疊層籠養(yǎng)的飼養(yǎng)密度分別可達(dá)16、22、28、48、60只/m2。本文據(jù)此飼養(yǎng)密度由公式(8)分析傳送帶干清糞蛋雞舍實(shí)現(xiàn)舍內(nèi)氣溫不低于13 ℃條件下,不同氣候地區(qū)不同飼養(yǎng)方式蛋雞舍建筑設(shè)計(jì)時(shí)外圍護(hù)結(jié)構(gòu)需滿足的熱阻值,分析結(jié)果見(jiàn)表3。
實(shí)際生產(chǎn)中,蛋雞的死淘率在低溫季節(jié)和產(chǎn)蛋期較高。不同飼養(yǎng)方式下蛋雞死淘率不同,死淘率導(dǎo)致蛋雞飼養(yǎng)密度降低,蛋雞舍冬季保溫性能提高才能控制舍內(nèi)溫度不低于13 ℃。全階梯籠養(yǎng)、半階梯籠養(yǎng)和疊層籠養(yǎng)(4層、6層、8層)等集約化飼養(yǎng)方式的飼養(yǎng)密度降低1只/m2,蛋雞死淘后根據(jù)蛋雞群飼養(yǎng)密度改變蛋雞舍冬季通風(fēng)量,3層全階梯籠養(yǎng)、4層半階梯籠養(yǎng)、4層疊護(hù)結(jié)構(gòu)最小傳熱阻不僅與不同氣候區(qū)的溫度有關(guān),而且與圍護(hù)結(jié)構(gòu)類(lèi)型密切相關(guān),應(yīng)考慮圍護(hù)結(jié)構(gòu)材料的熱惰性指標(biāo),中國(guó)根據(jù)熱惰性將外圍護(hù)結(jié)構(gòu)分為Ⅰ、Ⅱ、Ⅲ、Ⅳ型 4類(lèi)(∑D>6.0為Ⅰ型、∑D=4.1~6.0為Ⅱ型、∑D=1.6~4.0為Ⅲ型、∑D≤1.5為Ⅳ型)[19-20]。在綜合考慮蛋雞舍冬季保溫、通風(fēng)、防止外圍護(hù)結(jié)構(gòu)內(nèi)表面結(jié)露的要求下,根據(jù)圍護(hù)結(jié)構(gòu)最小傳熱阻的計(jì)算式(3),確定不同地區(qū)、不同類(lèi)型圍護(hù)結(jié)構(gòu)蛋雞舍建筑設(shè)計(jì)時(shí)需滿足的最小熱阻,部分城市圍護(hù)結(jié)構(gòu)冬季室外計(jì)算溫度參數(shù)見(jiàn)表1,蛋雞舍外圍護(hù)結(jié)構(gòu)冬季最低熱阻值見(jiàn)表2。層籠養(yǎng)蛋雞舍適應(yīng)的圍護(hù)結(jié)構(gòu)冬季室外計(jì)算溫度區(qū)域應(yīng)分別升高0.5 ℃的地區(qū);6層疊層籠養(yǎng)、8層疊層籠養(yǎng)通過(guò)改變通風(fēng)量基本可以維持蛋雞舍原有動(dòng)態(tài)熱平衡。6層疊層籠養(yǎng)、8層疊層籠養(yǎng)飼養(yǎng)方式下,蛋雞群飼養(yǎng)密度較大,死淘率導(dǎo)致飼養(yǎng)密度減小,但及時(shí)調(diào)節(jié)蛋雞舍通風(fēng)量,也可以維持蛋雞舍動(dòng)態(tài)熱平衡。

表3 不同氣候地區(qū)蛋雞不同飼養(yǎng)方式下的外圍護(hù)結(jié)構(gòu)熱阻Table3 Resistance of heat transfer for outer building envelope with different regions and feeding models of layer house m2··W℃ -1
不同氣候地區(qū)、不同飼養(yǎng)方式蛋雞舍建筑設(shè)計(jì)時(shí),考慮蛋雞的死淘率合理提高雞舍保溫性能更利于控制冬季舍內(nèi)溫差。全階梯籠養(yǎng)、半階梯籠養(yǎng)和疊層籠養(yǎng)(4層、6層、8層)等集約化飼養(yǎng)方式的飼養(yǎng)密度降低1只/m2,不同飼養(yǎng)方式對(duì)雞舍圍護(hù)結(jié)構(gòu)保溫性能的改善要求不同,分析結(jié)果見(jiàn)表4。

表4 不同飼養(yǎng)方式飼養(yǎng)密度降低1只/m2對(duì)雞舍圍護(hù)結(jié)構(gòu)保溫性能的改善要求Table4 Resistance of heat transfer for outer building envelope increased percentage with decreasing one hen per square meter under different feeding models of layer house
3.1 試驗(yàn)雞舍條件
為驗(yàn)證上述密閉式蛋雞舍冬季熱平衡系統(tǒng)模型,2015年1月17-24日在河北邯鄲永年縣華裕種雞示范場(chǎng)進(jìn)行了驗(yàn)證試驗(yàn)。
試驗(yàn)蛋雞舍長(zhǎng)90 m,寬11 m,高3 m;側(cè)墻小窗規(guī)格為長(zhǎng)0.65 m、寬0.23 m;蛋雞舍建筑墻體為370抹灰磚墻,屋頂為200 mm厚加氣混凝土,地面為普通水泥地面。試驗(yàn)蛋雞舍采用傳送帶清糞、行車(chē)自動(dòng)喂料、乳頭式飲水器飲水系統(tǒng);三層全階梯籠養(yǎng)、四列五走道布置形式;試驗(yàn)開(kāi)始時(shí),舍內(nèi)蛋雞為海蘭褐 10 671只、328日齡;試驗(yàn)蛋雞舍內(nèi)雞群密度為11只/m2。
3.2 試驗(yàn)方法
試驗(yàn)期間用HOBO U23-001型(美國(guó)Onset HOBO公司)溫濕度采集記錄儀采集蛋雞舍內(nèi)外溫、濕度,每5 min采集存儲(chǔ)1次,蛋雞舍外溫、濕度檢測(cè)點(diǎn)設(shè)在兩棟場(chǎng)區(qū)之間,舍內(nèi)測(cè)點(diǎn)(圖1)設(shè)在每列走道中間雞籠雞活動(dòng)高度位置,從濕簾端至風(fēng)機(jī)端分別在 5個(gè)過(guò)道依次距濕簾端5.9、33.0、60.1、87.2 m測(cè)定;NH3、CO2分別用VRAE PGM-7800/7840型手持式氣體檢測(cè)儀、HD-P900CO2檢測(cè)儀測(cè)試,測(cè)點(diǎn)布置從濕簾端至風(fēng)機(jī)端分別在 5個(gè)過(guò)道依次距濕簾端5.9、46.3、86.7 m測(cè)定;試驗(yàn)蛋雞舍采用 AC2000plus通風(fēng)控制系統(tǒng),風(fēng)機(jī)尺寸為 1.5 m× 1.5 m,通風(fēng)量在風(fēng)機(jī)開(kāi)啟穩(wěn)定后測(cè)量風(fēng)機(jī)風(fēng)速,按0.3 m× 0.3 m為一個(gè)單元,測(cè)得風(fēng)機(jī)36個(gè)測(cè)點(diǎn)的風(fēng)速。

圖1 舍內(nèi)溫濕度、NH3、CO2測(cè)定點(diǎn)布置示意圖Fig.1 Schematic of measuring locations of temperature, humidity, and NH3, CO2content in layer house
3.3 試驗(yàn)結(jié)果
雞舍建筑外圍護(hù)結(jié)構(gòu)參數(shù)取值參照《民用建筑熱工設(shè)計(jì)規(guī)范》[20],墻體、屋頂、地面的總熱阻分別為0.64、1.25、0.47 m2·K/W;按照熱惰性指標(biāo)D值,試驗(yàn)雞舍圍護(hù)結(jié)構(gòu)的熱惰性指標(biāo)D=4.841為Ⅱ型(∑D=4.1~6.0為Ⅱ型),試驗(yàn)雞舍建筑滿足最小熱阻值要求。

圖2 試驗(yàn)蛋雞舍內(nèi)外溫濕度變化情況Fig.2 Variation of temperature and relative humidity in layer house and outdoor
試驗(yàn)期間測(cè)得蛋雞舍室外平均溫度為?3.67℃,濕度為48.86%,測(cè)得蛋雞舍內(nèi)通風(fēng)量為0.42 m3/(h·只)。根據(jù)蛋雞舍熱平衡系統(tǒng)模型理論,得出試驗(yàn)場(chǎng)區(qū)蛋雞舍在未考慮冷風(fēng)滲透、侵入所造成熱量損失,理論條件下蛋雞舍內(nèi)溫度為13.85 ℃,試驗(yàn)測(cè)得溫?zé)岘h(huán)境參數(shù)變化結(jié)果如圖 2所示,蛋雞舍內(nèi)溫?zé)岘h(huán)境參數(shù)隨舍外環(huán)境變化波動(dòng)較小,蛋雞舍內(nèi)平均溫度為13.04 ℃,舍內(nèi)NH3、CO2濃度均在標(biāo)準(zhǔn)范圍內(nèi)。試驗(yàn)測(cè)得蛋雞舍內(nèi)溫度略低于理論溫度,其原因可能是試驗(yàn)蛋雞舍飼養(yǎng)密度略低且冷風(fēng)滲透、侵入造成部分熱量損失所致。
蛋雞舍實(shí)際生產(chǎn)應(yīng)用中,冷風(fēng)滲透不僅造成熱損耗,而且影響舍內(nèi)溫度場(chǎng)分布和氣流組織。蛋雞舍建筑相同縫隙面積下,雞舍內(nèi)外不同壓差形成的冷風(fēng)滲透量不同,造成的熱損失不同;蛋雞舍不同建筑外圍護(hù)結(jié)構(gòu)材料搭接方式不同形成的冷風(fēng)滲透量也不同[33]。本文研究分析中將不同氣候地區(qū)蛋雞舍建筑視為密閉性強(qiáng),未考慮不同壓差、縫隙下造成的冷風(fēng)滲透問(wèn)題,更完善的分析有待下一步試驗(yàn)繼續(xù)研究,以及冷風(fēng)滲透熱損失對(duì)蛋雞舍冬季保溫的影響。
1)本文根據(jù)不同氣候地區(qū)的圍護(hù)結(jié)構(gòu)室外設(shè)計(jì)溫度參數(shù)和維持舍內(nèi)13 ℃的正常生產(chǎn)最低氣溫需求,明確提出了中國(guó)不同氣候地區(qū)蛋雞舍建筑外圍護(hù)結(jié)構(gòu)應(yīng)滿足的低限熱阻參數(shù)取值。
2)為同時(shí)滿足冬季蛋雞舍最小通風(fēng)量和維持舍內(nèi)正常生產(chǎn)氣溫需求,3層全階梯籠養(yǎng)、4層半階梯籠養(yǎng)和4層疊層、6層疊層、8層疊層籠養(yǎng)等飼養(yǎng)模式最大飼養(yǎng)密度下,所適應(yīng)的圍護(hù)結(jié)構(gòu)冬季室外計(jì)算溫度區(qū)域應(yīng)分別不低于?14、?17、?19、?22、?23 ℃的地區(qū)。
3)試驗(yàn)驗(yàn)證表明,蛋雞舍在冷風(fēng)滲透、侵入等造成熱量損失,使蛋雞舍內(nèi)實(shí)際溫度低于理論計(jì)算溫度,溫差小于1 ℃,冷風(fēng)滲透問(wèn)題有待下一步試驗(yàn)繼續(xù)研究。
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Analysis and experiment on thermal insulation performance of outer building envelope for closed layer house in winter
Wang Yang1,2, Li Baoming1,2,3※
(1.Key Laboratory of Agricultural Engineering in Structure and Environment,Ministry of Agriculture,China Agricultural University, Beijing100083,China;2.College of Water Resources and Civil Engineering, China Agricultural University, Beijing100083,China; 3.Beijing Engineering Research Center for Animal Healthy Environment, Beijing100083,China)
The main considered environmental factors affecting performance of poultry is temperature. Thermal insulation performance of building component is the key factor that affects temperature stability, which is essential to ensure the bird’s well-being, maximum productivity and efficient feed utilization. Generally, laying hen houses are not equipped with heating system in winter, the temperature meets the requirements of layer hen rely on sensible heat production of layers. Bird’s sensible heat production and good insulation of building component are generally sufficient to maintain the houses temperature. If the stocking density is low or poorly insulated buildings, it’s difficult to meet the layer house environment requirements, including temperature, humidity and air quality. Improving thermal insulation performance of the building component would reduce heat loss and increasing stocking density could raise sensible heat production. However, ideal ventilation control system is required to ensure that aerial pollution emissions levels are within the acceptable limits and not to result in unnecessary ventilation heat losses. As such, minimum ventilation rate is particularly important. It is crucial for indoor temperature level and uniformity. Layer house minimum ventilation and air flow are crucial not only for indoor temperature and humidity, but also for temperature control uniformity. But there was a lack of information about the design theories. No information could be found in the literature that optimum relationship between thermal insulation performance of the layer house component and stocking density in laying-hen housing systems with different climatic regions in China. It was required to settle the urgent issue on how to determine the layer houses component thermal insulation performance under different climate zones, especially in the layer house building construction and environmental control fields. The objectives of this article was to analyze on minimum thermal resistance of building component in different climatic regions of China, and according the law of energy and quality conservation, to build dynamic heat balance model for layer house. A model was developed to determine the thermal insulation performance. It was important to build dynamic heat balance model in layer house, in order to maintain the temperature of the house of laying hen and to keep the healthy environment of layer hen. Those can reduce the energy consumption and construction cost, providing a guidance for laying house thermal insulation system design. In this paper, we conducted theoretical analysis and numerical calculation the building component minimum thermal resistance under the different climate regions and built steady-state heat balance theory model for layer house. Results showed that: 1) When calculated temperatures were -25 ℃ (Northeastern China), -15 ℃ (Northern and Northwestern China), -0 ℃(South of the Yangtze River China), the minimum thermal resistance of the layer hen houses walls should not be less than 0.778, 0.972, and 0.573 m2·℃/W, and the minimum thermal resistance for the ceiling should not be less than, 0.716, 0.266, and 0.333 m2·℃/W respectively for the above mentioned three regions. 2) A-frame cage of three tiers, semi-A-frame cage of four tiers, four overlap tiers cages, six overlap tiers cages, and eight overlap tiers cages, with maximum stocking density and outdoor design temperature should not be lower than -14, -17, -19, -22, -23 ℃. As such, dynamic thermal balance of layer house can be achieved. The results of this study provided theoretical foundation for the design of insulation system for closed layer hen house. Those research results can reduce the energy consumption and construction cost and providing a theoretical basis for layer house thermal insulation design system.
facilities; thermal insulation; thermal resistance; environmental control; closed layer house; outer building envelope; heat consumption; density of laying hen
10.11975/j.issn.1002-6819.2017.07.025
S831.9; X512
A
1002-6819(2017)-07-0190-07
2016-07-25
2017-03-10
國(guó)家863課題任務(wù)(2013AA10230602);國(guó)家蛋雞產(chǎn)業(yè)技術(shù)體系(CARS-41);國(guó)家自然科學(xué)基金面上項(xiàng)目(31372350)。
王 陽(yáng),女,博士生,山東濰坊人,研究方向?yàn)樾笄萁】淡h(huán)境及其控制技術(shù)。北京 中國(guó)農(nóng)業(yè)大學(xué)水利與土木工程學(xué)院,100083。
Email:wangyang512@cau.edu.cn
※通信作者:李保明,男,教授,浙江縉云人,博士生導(dǎo)師,主要從事畜禽設(shè)施養(yǎng)殖工藝與環(huán)境研究。北京 中國(guó)農(nóng)業(yè)大學(xué)水利與土木工程學(xué)院,100083。
Email:libm@cau.edu.cn