太陽能空調蓄熱水箱特性研究

2012-05-22 王愛輝 南京工業大學

  根據南京地區的太陽輻射強度及典型建筑負荷的日變化規律,得出單位集熱面積時可滿足的負荷建筑面積及蓄熱水箱溫度變化規律;并對幾種不同體積蓄熱水箱進行了分季節的啟動時間分析。結果表明,蓄熱水箱體積影響著戶式太陽能空調系統性能:夏季,在單位集熱面積的情況下,水箱體積以70L為基準,體積增大114%,熱水工作范圍減小54%,可承擔負荷減小25.2%,同時,體積增大到150L后啟動時間也變為原來的2倍以上,可見,蓄熱水箱體積越小越好,但它存在一個最小值隨著日工作時間的延長而增大;冬季蓄熱水箱體積對負荷的影響較小,但即使70L的水箱,冬季啟動耗時也比夏季多4h。

  關鍵詞:太陽能空調;蓄熱水箱;負荷建筑面積;水箱體積

  Abstract: The changing regularity of temperature in hot water tank and load of building reached under the unit area of collector was obtained according to the undulations of solar radiation intensity and load of typical buildings in Nanjing area,and the time for tank with different volumes to start-up was analyzed in summer and winter.The results show that the performance of the household air conditioning system is impacted by the volume of the tank : in summer,under the unit area of collector and the tank of 70L,with the volume increased by 114%,the range of the tempertature of hot water decreased by 54% and the building area of the load decreased by 25.2%,at the same time,with the volume increased to 150L,the time for start-up is twice longer than before,that said,it was better,the tank smaller,but the minimum volume is existed,which with the extending of working time bigger and bigger;in winter,the effect of the tank volume on the load is small,but the time for start-up is 4 hours longer in summer than in winter,with the tank of 70L.

  Keywords: solar air conditioning;hot water tank for heat storage;the building area of load;the volume of the tank

  隨著人們對環境問題的重視及能源的緊張,對清潔無污染的太陽能的開發和利用顯得相當重要。太陽能空調系統作為其中不可或缺的一部分,近年來得到廣泛的關注[1]。但是對于太陽能空調系統中的蓄熱問題,一直是困擾太陽能空調發展的重要問題,之前很多學者對蓄熱水箱以溫度分層水箱為模型做了研究[2,3],為蓄熱水箱容積的確定奠定了理論基礎,但現階段較為穩定可靠的還是整體式的水箱。本文對整體式水箱從體積大小和南京地區房間負荷的季節變化出發,研究單位集熱面積下,無輔助熱源時,系統不同季節的可承擔負荷及啟動特性,為戶式太陽能空調系統的節能研究提供依據。

  (1) 對于太陽能空調系統,夏季單位集熱面積下,蓄熱水箱以70L 為基準,體積增大114%時,熱水工作范圍減小54%,可承擔負荷減小25.2%,即體積是越小越好的,但又不能太小使得熱水工作溫度超過臨界值,可是隨著日工作時間的延長,最小體積需要增大; 冬季時,水溫和負荷對體積的要求較低;

  (2) 系統的啟動與蓄熱水箱的體積密切相關,無論冬季還是夏季,蓄熱水箱體積增大114%達到150L,啟動時間都延長為2 倍以上; 分季節來看,蓄熱水箱為70L 時,夏季啟動也比冬季要少用時25%,而體積越大,這個值也越大;

  (3) 如何使夏季蓄熱水箱工作體積的最小值更小而容熱能力更強,與此同時,降低水箱內水溫的逐時變化率,提高單位集熱面積可承擔的負荷及系統的穩定性,并使啟動加速,是一個值得探討的問題。

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