建築物外遮陽遮蔽效果分析與模擬

Abstract

外遮陽裝置可減少從窗戶進到室內的太陽輻射量，降低室內溫度，進而降低空調耗電量，達到節能目的。然而現在國內外遮陽規範計算外遮陽係數ki方法多有缺漏，文獻中缺乏完整且詳細之計算流程及假設。例如，水平、垂直、格子遮陽板之外遮陽係數ki只有一種表格，但外遮陽係數ki和窗戶高寬比有很大的關係，現行國內規範中並未說明製作外遮陽係數ki所使用的窗戶高寬比。 此外，有無考慮漫射和反射輻射項、漫射和反射輻射遮蔽係數、遮陽板與窗戶距離，使用之氣象資料、地點、計算ki的期間(全年期、溫熱期、冷涼期)都會影響到外遮陽係數ki。 本研究將國內外文獻整理成一套有系統的理論架構，並以MATLAB撰寫分析程式，與文獻驗證比較結果相符。再者，本研究計算台灣地區水平、垂直、格子、百葉遮陽板遮蔽太陽輻射的效果，提出不同窗戶比例、時期的外遮陽係數ki,prop表(prop表示由本研究提出之意)供後人參考使用。並以Abaqus 6.11模擬室內溫度與本研究團隊現有的實驗數據比較。

The application of external shading system could block out unwanted radiant heat gain, thus reduces the cooling load and conserves energy. However, domestic and international standards lack of complete and detailed calculation procedure of shading factor, the reduction factor of solar radiation in presences of obstructions. For instance, the ratio between height and width of the window influences shading factor a lot, but there is only a table of shading factor for each kind of external shading devices. In addition, shading factor varies with whether diffuse irradiance and reflect irradiance terms, effect of external shading devices on obstructing direct, diffuse, reflect irradiance is considered in the calculation, and with the geometry of window and shading devices, the time and location of weather data and reference period. The objective of this research is to propose calculation procedure. The algorithms have been written in MATLAB language and verified by other references. Futhermore, this paper presents shading factor ki,prop of horizontal, vertical, egg-crated shading devices and louvers in various window ratio and reference period. A numerical model is built in Abaqus 6.11 to compare room temperature with existing experimental data.