本論文採用CFD 建築通風用模擬軟體FloVENT,研究地板送風系統對於
臺灣建築科技中心六樓辦公室的室內環境。本研究分為兩部分。第一個目的是驗證建築物的實驗測量值。模型考慮以下兩種邊界條件, 壁溫固定與壁面固定熱通量。結果顯示, 利用在強制對流垂直平板中兩個無因次化參數Nu數和Re 數與自然對流中Nu 數和Ra 數之間的關係, 計算對流熱傳係數設定於壁溫固定邊界條件中, 與具有相似總熱傳量的壁面固定熱通量邊界條件之模擬皆能得到與實驗結果近似的垂直溫度曲線。研究探討相同風量條件下, 不同加熱位置對於室內環境的影響程度。結果顯示加熱位置不僅改變噴流高度, 也改變了溫度分布與冷風感舒適程度。地板加熱的模型, 供風的噴流高度為浮力噴流尺度的1.2倍與1.14倍, 會出現較低的溫度分層與過渡層區間, 小腿高度0.3 m 會出現不舒適的冷風感。牆面加熱的模型, 供風的噴流高度約為浮力噴流尺度的1.3倍, 遠離風口後皆能達到舒適的冷風感。結果也顯示牆面加熱的模型由於上層區域於牆面持續輸入熱量, 上層區域會出現比下層與過渡層更大的溫度梯度。研究探討不同風量條件下對於室內的影響, 結果顯示提高風量會提高溫度分層與過渡層區間, 同時人體站立高度1.7 m 會出現較多比例的不舒適冷風感。

This study uses CFD simulation software to study the indoor environment characteristics of the space with the underfloor air distribution (UFAD) system. There are two parts of this study. The first part of this CFD simulation study is to verify the numerical model, and that was conducted by comparing the numerical simulation results with the experimental measurements in a real building. The heat transfer condition on the boundary plays a significant role in the simulation model. The following two heat transfer boundary conditions are considered in this indoor space. One is the constant temperature, and the other is the constant heat flux. The convection heat transfer coefficient is estimated in the regime of forced convection for a vertical plate. This study shows that the simulation cases of two different boundary conditions with similar total heat transfer rates give approximate temperature stratification results. The simulation cases with the proper total heat transfer rates provide reasonable temperature stratification results compared with the experimental field measurements in a real building. The second part of this study investigates the characteristics of temperature distribution in the space which has different heat source conditions, i.e. heating by the surrounding walls and the ground floor. The simulation results show that the stratification height of the ground floor heating case is less than that of the surrounding walls heating case for the same supply flow rate. The throw height of the supply air from the diffuser is about 1.3 times the buoyant jet length scale for the surrounding walls heating case. In the ground floor heating case, the throw height is about 1.19 times and 1.14 times the buoyant jet length scale. The results show that the ground floor heating case may induce unsatisfied draught rating at 0.3 m due to the velocity difference to large. The results reveal that the heating location condition not only changes the stratification height but also varies the temperature distribution performances, especially for the upper layer. In the surrounding walls heating case, the largest temperature gradient takes place in the upper layer. In general, the stratification height and the transition layer are higher when the supply air flow rate increases.

[1] 經濟部能源局, 2017, 2017非生產性質行業能源查核年報。
[2] Kim, G., Schaefer, L., Lim, T.S.& Kim, J.T., 2013, Thermal
comfort prediction of an underfloor air distribution system in a
large indoor environment. Energy and Buildings 64, 323-331.
[3] Bauman, F., 2003, Underfloor air distribution (UFAD) design
guide. American Society of Heating Refrigerating and Air Con-
ditioning Engineers, Inc., Atlanta, GA, ISBN, 1-031862-21-4.
[4] Kong, Q. & Yu, B., 2008, Numerical study on temperature strat-
ification in a room with underfloor air distribution system. Energy
and Buildings 40 (4), 495-502.
[5] Wan, M. & Chao, C., 2005, Numerical and experimental study
of velocity and temperature characteristics in a ventilated with
underfloor ventilation systems. Indoor air 15 (5), 342-355.
[6] Fan, Y., Li, X., Yan, Y.& Tu, J., 2017, Overall performance
evaluation of underfloor air distribution system with different
heights of return vents. Energy and Buildings 147, 176-187.
[7] 林子安, 2015, 地板送風系統之數值模擬研究。國立台灣科技大學碩士
論文。
[8] 王鈞廷, 2016, 實驗量測地板送風系統供風口特性之研究。國立台灣科
技大學碩士論文。
[9] Atienza-Marquez, A., Fernandez-Hernandez, F., Dominguez-
Munoz, F.& Cejudo-Lopez, J.M., 2018, Detailed and simplified
models of a terminal unit that combines an UFAD system with
a floor cooling. Applied Thermal Engineering 129, 1079-1091.
[10] Fanger, P.O., Melikov, A.K., Hanzawa, H.,& Ring J., 1988 Air
turbulence and sensation of draught. Energy and Buildings 12,
21-39.
[11] ISO Standard 7730, Economics of the thermal environment an-
alyticaldetermination and interpretation of thermal comfort us-
ing calculation of the PMV and PPD indices and local thermal
comfort criteria, 2005.
[12] Reynolds, A.J., 1975, The prediction of turbulent Prandtl and
Schmidt numbers. International Journal of heat and mass transfer
18, 1055-1069.
[13] Reynolds, A.J., 1976, The variation of turbulent Prandtl and
Schmidt numbers in wakes and jets. International Journal of
heat and mass transfer 19, 757-764.
[14] Launder, B.E., and Spalding, D.B., 1974, The numerical com-
putation of turbulent flows. Appendix D of computer methods in
applied mechanics and engineering 3, North-Holland Publishing
Company 269-289.
[15] Mentor Graphics Corporation, FloVENT background theory
reference guide, Siemens Product Lifecycle Management Soft-
ware Inc., Unpublished work.
[16] 王惠民,2005, 流體力學基礎(第二版) Introduction to fluid mechan-
ics, 清華大學出版社, ISBN 978-7-3021-1469-7.
[17] Yunus, A.C, 2004, Heat transfer a practical approach, Mcgraw-
Hill, ISBN: 0-07-123644-9
[18] Park, H. J., Holland, D. The effect of location of a convective
heat source on displacement ventilation: CFD study, . Environ.
vol. 36, 2001, pp. 883-889.
[19] 蔡廷亞, 2013, 實驗測量研究地板送風系統應用於台灣建築科技中心
大樓之室內環境。台灣科技大學碩士論文。
[20] Agonafer, D., Gan-Li,L. and Spalding, D.B., The LVEL tur-
bulence model for conjugate heat transfer at low reynolds num-
ber. EEP-Vol. 18, Application of CAE/CAD Electronic Systems.
ASME 1996.
[21] Rabe, H,2017, A CFD study on the interaction of velocity and
temperature characteristics in an underfloor air distribution sys-
tem, 台灣科技大學碩士論文。
[22] Lee, J. H.W. and Chu, V. H. (2003), Turbulent jets and plumes.
Kluwer Academic Publishers, ISBN: 978-1-4020-7520-9.
[23] 內政部建研所, 2014, 103年度永續綠建築與節能減碳科技中程個案計
畫協同研究計畫。
[24] 李波, 2014, FloTHERM 軟件基礎與應用實例. 中國水利水電出版社
ISBN: 978-7-5170-1823-0.
[25] 魏文禮, 2011, 紊流力學基礎. 陝西科學技術出版社ISBN: 978-7-
5369-4950-8.