氣冷式冰水機組流場模擬分析

Airflow Simulation of Air-Cooled Water Chiller Units

鄭百晟(Pai Chen Cheng)

指導教授 ： 施陽正

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(2011年)

https://doi.org/10.6841/NTUT.2011.00315

摘要

氣冷式冰水機組之冷凝器為一種透過對流的散熱元件，廣泛地運用在空調冰水機之散熱元件，係使冷凝器與空氣接觸，達到將冷凝器冷卻之目的的設備。由於散熱時需要大量外氣來冷卻冷凝器，因此需要特別注意各氣冷式冰水機組間距以提供足夠的外氣來冷卻；或可加裝風筒來減少熱風回流之影響。在本研究利用計算流體力學研究重要物理參數(包括風速、風向、大氣邊界層及加裝風筒)對氣冷式冰水機組的散熱效應。根據數值模擬結果得知：(1)無風(0m/s)狀態下，出風口送風高度較高，氣冷式冰水機組散熱效率較高；(2)有風筒設置之送風高度較高，散熱效率也較高；(3)當大氣邊界層存在時，壓制氣冷式冰水機組出風的情況嚴重，導致氣冷式冰水機組散熱效率變差；(4)不同風向可能導致前列氣冷式冰水機組發生較強風切效應，因而散熱效率較差。本文之研究分析可預先提供廠商設計規劃建置，以確保設備性能效率，並減少建築物設備測試的施工成本，可提供給相關單位良好參考。

關鍵字

熱回流率 ； 計算流體力學 ； 氣流模擬 ； 氣冷式冰水機組

並列摘要

Air-Cooled Water Chiller Units (ACWCU) was used as a component for heat rejection by means of heat convection. Through the contact with air, the high-temperature condenser can be cooled down. Because the cooling of the condenser needs a great amount of outdoor air, the spacing between ACWCU should be large enough. Alternatively, installing stacked tower could reduce the occurrence of short recirculation and enhance the cooling of the condenser. This study adopted the CFD method to investigate several parameters, including wind speed, wind direction, atmospheric boundary layer and stacked tower, on the impact of heat rejection of ACWCU. According to the numerical results: (1) ACWCU could have better thermal efficiency under the condition of no wind t; (2) installing stacked towers could avoid short recirculation more effectively; (3) the existence of atmospheric boundary layer could suppress the growth of thermal plumes issuing from ACWCU, resulting in poorer thermal efficiency of the system; (4) wind direction played an important role on the thermal efficiency of ACWCU. The results of this study can provide the guidance for manufacturers to install ACWCU and improve their thermal efficiency.

並列關鍵字

Efficiency of thermal recirculation ； Computational Fluid Dynamics(CFD) ； Airflow simulation ； Air-Cooled Water Chiller Units (ACWCU)

參考文獻

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