【摘要】：相變材料具有儲能密度大、儲能能力強、相變過程中溫度恒定等特點,它在相變過程中能夠吸收(釋放)大量熱量,非常適用于能量儲存的材料。把相變材料制成相變單元放置太陽能蓄熱水箱中,可提高水箱儲能密度、增加太陽能蓄熱水箱的蓄熱量,提供更多的生活用水；同時將相變材料制成相變單元,使相變材料能夠靈活應用于余熱回收、新能源利用和電力調(diào)節(jié)等領域。以實驗與模擬作為主要的研究手段,從相變單元的設計,太陽能-相變蓄熱水箱的設計到圓柱體相變單元的蓄放熱特性以及太陽能-相變蓄熱水箱的運行特性等方面進行了相關(guān)研究： 首先在選擇了適合應用于太陽能蓄熱的相變材料后,設計了圓柱體相變蓄熱單元,并通過數(shù)值模擬的方式對圓柱體相變蓄熱單元在60℃、70℃、80℃三種溫度工況下的相變規(guī)律進行了模擬研究。圓柱體相變單元在三種溫度工況下的熔化規(guī)律都為自上而下,由外而內(nèi)；凝固過程圓柱體相變單元呈現(xiàn)出由相變單元的壁面向中間逐漸凝固的規(guī)律。 然后通過實驗對比研究了不同強化傳熱方式下圓柱體相變蓄熱單元的蓄放熱特性,同時對圓柱體相變蓄熱單元內(nèi)相變材料的溫度分布進行了研究,并得出膨脹石墨對提高相變材料的傳熱性能比方形金屬網(wǎng)格與圓形金屬網(wǎng)格更為明顯的結(jié)論。 最后以西昌地區(qū)的太陽能資源為例,計算出滿足西昌地區(qū)一個三口之家的生活熱水需要太陽能集熱器面積為2.4m2、集熱水箱的容積為180L,并在此基礎上根據(jù)課題組前期的研究成果設計了太陽能-相變水箱及其蓄熱系統(tǒng)。計算出了太陽能-相變水箱中相變材料的填充率,結(jié)果表明蓄熱水箱中填放41個圓柱體相變蓄熱單元在冬季的西昌地區(qū)就可以比普通太陽能蓄熱水箱多儲存45.7L的生活熱水。在此基礎上將太陽能-相變水箱與太陽能集熱系統(tǒng)進行耦合成完整的蓄熱系統(tǒng),通過通過模擬計算對太陽能-相變水箱內(nèi)部的運行特性進行了研究,對水箱內(nèi)部溫度場分布與相變材料蓄放熱特性進行了相關(guān)分析。在加裝相變蓄熱單元后,蓄熱水箱的蓄熱時間為285min,連續(xù)放熱過程的時間為42min；在用水間隔為5mmin的情況下,水箱出水溫度在40℃以上的時間為89min；用水間隔為10min的情況下,水箱出水溫度在40℃以上的時間為85min。
[Abstract]:Phase change material has the characteristics of high energy storage density, strong energy storage ability and constant temperature during phase transformation. It can absorb (release) a large amount of heat during the phase transition process, so it is very suitable for energy storage materials. When the phase change material is made into a phase change unit and placed in the solar energy storage tank, the energy storage density of the water tank can be increased, the heat storage of the solar energy storage water tank can be increased, and more domestic water can be provided. At the same time, the phase change material is made into phase change unit, which can be used flexibly in the fields of waste heat recovery, new energy utilization and electric power regulation. Using experiment and simulation as the main research means, from the design of phase change unit, The design of solar-phase change storage tank is related to the heat storage and exothermic characteristics of the cylindrical phase change unit and the operation characteristics of the solar-phase change storage tank. After the phase change material, The cylindrical phase change heat storage unit is designed, and the phase transition law of cylindrical phase change heat storage unit at 60 鈩，

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