被動式冷卻樑板應用於辦公室環境之氣流模擬分析研究

CFD Analysis for the Passive Chilled Beam Applied in an Office Environment

蘇偉安(Wei-An Su)

指導教授 ： 李魁鵬

國立臺北科技大學/機電學院/能源與冷凍空調工程系碩士班/碩士(2014年)

https://doi.org/10.6841/NTUT.2014.00760

摘要

本研究針對冷樑送風系統之氣流模擬分析，探討其溫度場、速度場、相對濕度及PMV舒適度指標。此外針對冷樑(chilled beam)的結露問題，透過有外氣滲透風的方式，探討冷樑在夏季的晴天及雨天不同的相對濕度下，其冷樑冰水盤管表面的結露現象，以提供業主或設計者在設計冷樑系統時能妥善考慮冷樑冰水盤管的冰水供給溫度，避免結露產生。
使用CFD軟體依不同的冷樑冰水盤管表面溫度(18℃、19℃、20℃、21℃)及夏季晴天與雨天外氣滲透進入室內的不同相對濕度(72.9%、90%)，共設計出7種case藉以分析在不同參數配置下的舒適度及結露現象。研究結果可以看出冰水盤管表面溫度越低結露現象越是明顯，且外氣滲透進室內的濕度也重大影響結露與否，其中在滲透風的相對濕度為72.9%時，冰水盤管在表面溫度為19℃時可以避免結露，而在滲透風的相對濕度為90%時，冰水盤管表面溫度則必須提高至21℃才可以避免結露。
本研究採用舒適度指標PMV綜合計算空氣溫度、平均輻射溫度、風速、相對濕度、著衣量及發塵量等六種數值以判斷人體的舒適度，由研究結果顯示，有外氣滲透風進入室內的Case2~Case7皆維持在良好舒適度範圍內，而頭部及腳踝垂直最高溫差僅0.5℃，不會對室內使用者造成不快。

關鍵字

冷卻樑板 ； 結露現象 ； 熱舒適(PMV) ； 計算流體力學

並列摘要

This study aimed at the air distribution simulation of chilled beam systems. The temperature, velocity and relative humidity fields were analyzed to determine the predicted mean vote (PMV) for the application of chilled beam air-conditioning. In order to investigate coil condensation, the simulations of infiltration effects at different relative humidity in the summer of sunny and rainy days were studied, to provide owners or designers proper information when designing the chilled water temperature of cooling coils to avoid condensation.
Different cases of chilled water temperature of cooling coils(18℃、19℃、20℃、21℃) and different relative humidity(72.9%、90%) of air infiltration in the summer of sunny and rainy days investigated for the impact on the thermal environmental conditions for human occupancy and coil condensation. The results show that if the chilled water temperature of cooling coils is colder, the coil condensation is more serious. And the humidity of air infiltration is also a significant impact on condensation. The case condition of relative humidity of air infiltration is 72.9,and the chilled water temperature of cooling coils at 19℃ can avoid condensation, if the case condition of relative humidity of air infiltration is 90%, the chilled water temperature of cooling coils must increase to 21℃ to avoid condensation of cooling coils.
The thermal comfort indicator PMV which is based on air temperature, mean radiant temperature, wind speed, relative humidity, clothing and metabolic rate was calculated to study the human thermal comfort level. The results show the case2 to case7 are maintained in good comfort level, and the maximum temperature difference between the vertical head and feet is only 0.5℃,which does not cause thermal discomfort for the occupant.

並列關鍵字

Chilled Beam ； Condensation of Moisture ； Predicted Mean Vote (PMV) ； CFD

參考文獻

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