【摘要】：能源與環(huán)境是現(xiàn)今世界可持續(xù)發(fā)展中最受關注的熱點問題之一。青藏高原地區(qū)太陽光資源豐富,同時一年中大部分時間氣候寒冷。溫室若夜間不加熱難以維持作物生長,傳統(tǒng)的加熱方式需要消耗大量化石燃料能源,同時產(chǎn)生大量有毒有害溫室氣體,污染環(huán)境。高效節(jié)能型溫室種植蔬菜在青藏高寒地區(qū)推廣應用,能有效克服惡劣多變的天氣,解決反季節(jié)蔬菜生產(chǎn)問題,基本達到當?shù)厝藗儗κ卟说男枨?具有顯著的經(jīng)濟和社會效益。因此新能源太陽能存儲相變材料在溫室環(huán)境的調(diào)控模式,便成了溫室工程技術(shù)領域追求的新目標。以芒硝(Na_2SO_4·10H_2O)為主相變材料,采用物理共混法,篩選出合適添加輔助材料組成多元混鹽體系,制備出相變溫度在10~25℃左右的三種Na_2SO_4·10H_2O基復合相變材料,添加成核劑、防相分層劑、導熱劑等對相變材料進行進一步優(yōu)化。通過熱重分析(TG)、T-history曲線、差示掃描量熱法(DSC)熱常數(shù)分析(Hot Disk)等方法表征了相變材料相變溫度、相變潛熱和導熱等性能。然后采用真空吸附法,以膨脹石墨為載體,制備出導熱增強型膨脹石墨/復合Na_2SO_4·10H_2O定形相變材料。最終將芒硝基復合相變材料放置于模擬溫室中探究相變材料保溫性能。結(jié)果表明:當Na_2SO_4·10H_2O 86.4%、Na_2CO_3·10H_2O9.6%、NaCl 4%時,相變溫度為24.6℃。對其改性添加成核劑硼砂4%,增稠劑羧甲基纖維素鈉1.5%,導熱劑石墨粉1%時,復合相變材料導熱系數(shù)為1.0216W/(m·K),材料相變潛熱為127kJ/kg,經(jīng)過300次相變循環(huán),材料仍舊能保持較好的相變性能。最后將此材料在簡易模擬溫室中試驗,當芒硝基相變材料添加量為25、35和45kg時清晨日出前最低溫度分別可以提高1、3.6和4.4℃。表明該芒硝基復合相變材料適用于高寒氣候環(huán)境下簡易溫室。芒硝基相變儲能材料制備方法簡單,成本低,環(huán)境友好,在高寒地區(qū)溫室中具有良好的保溫性能,還可以與傳統(tǒng)溫室控溫方法結(jié)合,在溫室保溫方面具有廣闊應用前景。
[Abstract]:Energy and environment are one of the hot issues in the sustainable development of the world. The Qinghai-Xizang Plateau is rich in solar light and has a cold climate for most of the year. If it is difficult to maintain crop growth in greenhouse without heating at night, the traditional heating methods need to consume a large amount of fossil fuel energy, produce a large number of toxic and harmful greenhouse gases, and pollute the environment at the same time. The popularization and application of high efficiency and energy saving greenhouse planting vegetables in Qinghai-Tibet alpine region can effectively overcome the bad and changeable weather, solve the problem of off-season vegetable production, basically meet the local people's demand for vegetables, and have remarkable economic and social benefits. Therefore, the regulation mode of new energy solar energy storage phase change materials in greenhouse environment has become a new goal in greenhouse engineering field. With Na_2SO_4 10H_2O as the main phase change material and physical blending method, the suitable auxiliary materials were selected to make up the multi-component mixed salt system. Three kinds of Na_2SO_4 10H_2O based composite phase change materials with phase transition temperature of about 10 ~ 25 鈩，

本文編號：2302876