可變風量低溫差送風空調機開發與性能研究

Development and Performance Study of Low Temperature Differential VAV Fan-Coil Unit

翁國亮(Kuo-Liang Weng)

指導教授 ： 柯明村

國立臺北科技大學/機電學院/機電科技研究所/博士(2006年)

摘要

針對傳統空調系統之研究，大筆經費往往是投注在主機系統性能之提高，而忽略空氣處理端才是整體空調系統舒適、省能的根本。惟有在空氣處理側滿足使用者舒適的需求與節能的目的之後，再予以提升空調系統中其它元件之性能，才能在整體系統效能提昇中獲得彰顯。
本研究試圖找出能確保滿足人體舒適與健康的最佳空氣側設備及其控制策略，並完成其產品之開發，讓使用者在滿足舒適的需求下，建立真正舒適、健康、省能的正確觀念，落實維護地球永續發展以及節能、減廢共創舒適地球村的目標。
本研究即根據傳統VAV空調系統，其空調能力隨耦於空調負荷之優點，結合低溫差送風嶄新觀念，首創將空調機供風量與空調能力隨空調區間需求離耦個自獨立控制的方法，完成「低溫差送風可變風量送風機」(Low Temperature Differential-VAV FCU, LTD-VAV FCU)的開發與特性研究。本研究建立了LTD-VAV FCU之性能檢測操作流程，並於空調設備性能實驗室在相關標準環境條件下進行性能實驗。經由實驗結果得知，在冰水入水溫度7 ℃時，本LTD-VAV FCU供風量可由0.33 (700CFM)至0.14 (300CFM)之間無段調變，最大空調能力至最小空調能力之空調能力變動率為84.8%，此時空調能力在5.26 kW至0.8 kW間變化，表示空調房其負荷在此範圍內變動，LTD-VAV FCU皆能隨空調負荷控制空調能力之供應，使空調房內溫度維持於微小溫度帶內，而其供回風溫度差最小可低至3℃左右。
採低溫冰水2℃時，供風量由0.33 (700CFM)至0.14 (300CFM)調變，空調能力在6.79 kW至0.95 kW間變化，最大空調能力至最小空調能力之空調能力變動率為86%。其空調能力可提昇29 %，空調能力變動率亦較佳，其供回風溫差可低至3.8℃。由以上結果顯示本設備運用於儲冰低溫冰水系統，仍然可依空調負荷之變動，藉由變風量與變風門開度雙重控制的特性自行調變供風量及空調供應能力，達成低溫差送風之舒適、節能理想目標。
本研究在數值模擬方法解析方面，已建立出LTD-VAV FCU之三維數值分析模式，解析空調區域內固定負荷及動態變動負荷時的溫度與流場分佈情形，並針對其溫度場、速度場及空氣混合程度等，探討LTD-VAV FCU應用於實際場所運轉時的使用情形，此方式可減少在設計過程中可能的錯誤判斷，大幅縮減其設計成本與時間。而本研究建立之數值分析模式可供後續研究參考，將使LTD-VAV FCU未來在工程與設計之運用及推廣上更易落實，為本研究獲得最大效益之一。
本研究在產品開發方面，已完成此低溫差送風空調嶄新技術之建立，以及其設備之開發。LTD-VAV FCU不但保有VAV空調送風節能優點以最少的能耗提供最健康舒適的環境，更徹底解決傳統定風量與變風量送風技術之所有缺失。另外本研究建立之LTD-VAV FCU性能檢測操作流程，可適用於所有VAV FCU之性能檢測，亦可供後續研究參考使用。由上述成果本研究預期在人類熱舒適意識進化歷程中，將使熱舒適進化對經濟能力與生活品質之深刻影響影響作出重大貢獻。

關鍵字

低溫差送風 ； 計算流體力學 ； PMV ； PPD ； VAV

並列摘要

The researches in the traditional air conditioner system, funds and resources were generally focused on improving the performance of its main system. However, it is disregarded that airflow management end is the critical origin of the air condition system to create a comfortable and energy saving running environment. Only after the users’ requirement on comfort and economy achieved from the air management end, the tuning on components in an air condition system to improve its function would then realize the synergy upgrade in an air condition system
This thesis intends to study at the air management end for a optimal equipment and the control strategy to satisfy the comfort and health for human lives. And the proposition will be applied to accomplish the physical instrument to meet the consumers’ living expectations. It would induct a feasible notion to the commonalty about the correlations in the air condition system- the comfort, the health and the economy. And hence all people in the global village would be oriented to regard the issues on energy consuming and redundancy control.
The implementation of function and its study of the Low Temperature Differential- VAV FCU (LTD-VAV FCU) are achieved in the research. Which adopts the knowledge on the advantage in the traditional VAV air condition system- the capacity of an air condition system is depended on its workload, and integrates the new idea- air is pushed between the temperature differentiated areas. It initiates the originality on controlling the air flow and system workload to comply with the diversified on-demand of air supply in the air conditioning spaces. For the research, an operation procedure is set up for the verification to LTD-VAV FCU in an air conditioning function test laboratory, which equipped to accord with relevant regulation standards. Learned from the experimental result, when the temperature of the in-flow cold water controlled at 7˚C, the air flow from this LTD-VAV FCU could be adjusted from 0.33 (700CFM) to 0.14 (300CFM) in a free rate. The variation rate of air conditioning capability is 84.8% from its maximal to the minimal. Meanwhile, the air conditioning capability is ranging between 5.26 kW and 0.8 kW. It indicates that the load of air conditioning system in the room is varying within this range. By managing capacity supply comply with workload control, the LTD-VAV FCU hence sustain the temperature in the room to a fine range. And the temperature difference between air outflow and inflow can be minimized to 3˚C.
As the inflow cold water controlled at 2˚C, the air outflow volume adjusted from 0.33 (700CFM) to 0.14 (300CFM), and the air conditioning capability varied between 6.79 kW and 0.95 kW, the variation rate of air conditioning capability is 86% from its maximal to the minimal. A 29% improvement is raised at the air conditioning capability. A better variation rate of air conditioning capability is revealed. The temperature difference between air outflow and inflow can be minimized to 3.8˚C. Concluded from the above experimental outcomes, this equipment, applied in the cold water ice circulation system, achieves the objective on heat difference to move the air flow at a low temperature environment, by controlling the change of the workload in the air conditioning system to manage both the air volume variation and the open level of its ventilator to adjust the air volume and the air conditioning capability automatically.
On the aspect of numerical simulating analysis, a 3-D numerical analysis model for LTD-VAV FCU is set up this research to analyze the distribution situation of temperature field and flow fields at constant load or dynamic load in the air conditioning space. The operation of the LTD-VAV FCU in a practical running is also addressed, referring to the parameters on its temperature field, speed fields and the degree of mixing air. The references so reduced the possibility to a wrong determination in the program, and generated the profit on cost-effective and time-saving. The model for numerical analysis built in this research can be cited for the follow-on researches. The most of the benefit from this research is that it will make LTD-VAV FCU easier on its implementation and popularization at engineering and production application in the future.
On the practical production in this research, a real machine is completed with the new technology of low temperature differential fan-coil air conditioning. LTD-VAV FCU not only keeps the advantage of energy-conservation at VAV air conditioning system providing a healthy and comfortable environment with the minimal energy consuming, moreover it also solves all the defects in the traditional technologies with constant or variable air volume fan-coil. In addition, the operational procedure on performance test for LTD-VAV FCU in this research can be applied to the performance test on any VAV FCU system. It will also be served as a reference for further succeeding studies. We expect above-mentioned achievements in this research would contribute to the human beings awareness on heat comfort study, which would consequently arouse the heat comfort evolution to make progress on the economical activities and the quality of human life.

並列關鍵字

Low Temperature Differential ； CFD ； PMV ； PPD ； VAV

參考文獻

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