太陽能中高溫空氣集熱系統之研發

Research of Solar High-Temperature Air Heating System

洪振堯(Jhen-Yao Hong)

指導教授 ： 李文興

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(2012年)

摘要

目前太陽熱能的主要用途集中於家用熱水，若能利用熱交換器將此熱水的能量傳給空氣，使其變成中高溫的熱空氣，將可應用於乾燥或加熱製程上。
一般而言，空氣經由熱交換後其溫度大約為40~50℃，而本研究利用新設計的中高溫空氣集熱系統搭配太陽能集熱系統，能使空氣提升到80℃以上。
然而太陽能中高溫空氣集熱系統是依據標準設計的流量與風量去選擇泵浦與風機的規格，此舉可能造成電能的浪費。本研究利用最佳效率點追蹤控制系統，使泵浦與風機能在最少的耗能下，得到性能係數COP之最大值。而性能係數COP的定義為空氣能量與泵浦跟風機所提供的能量之比值。實驗結果證明，在變頻控制的操作下，太陽能中高溫空氣集熱系統運轉效能COP可達25，比起無變頻控制的操作下，其運轉效能COP只為5.2。
在不同日照量變化的情況下，其集熱器與空氣的效率皆不同，而效率的定義為集熱器(或空氣)與太陽能能量之比值。由實驗結果得知，在平均日照量為511W/m^2且有部分時段穩態時，使泵浦與風機實行全速運轉，其集熱器效率可達到62％，而空氣效率為51%；而在平均日照量為790W/m^2且穩態時，使泵浦與風機實行變頻運轉，其集熱器效率為59％，而空氣效率為46%。
利用變頻控制使泵浦整日耗能從無變頻控制的7.7MJ減少至有變頻控制的2.2MJ，其省能71.4%；風機整日耗能從無變頻控制的21.2MJ減少至有變頻控制的5MJ，其省能 76.4%，有效提升應用價值。

關鍵字

太陽能 ； 真空管 ； 集熱器 ； 自動控制

並列摘要

The main purpose of solar thermal energy focuses on domestic the hot water at present. The hot water energy will be transferred to the air by using the heat exchanger. The air will be turned into the high temperature, and it can be used in drying or heating process.
Generally speaking, outside air runs through the heat exchanger, and the temperature is about 40~50℃. This study uses new design of high-temperature air heating system with solar collector system, and the air can be increased to more than 80℃.
Solar high-temperature air heating system chose the specification of pump according to the standard flow rate. This may result in waste of electricity energy. This study uses the optimal performance point tracking control system. The pump and fan are minimum energy consumption, and the COP is Maximum. The definition of coefficient of performance is the ratio of air energy with pump and fan energy. The test results show that the COP of solar high-temperature air heating system is 25 by frequency conversion control, and it is 5.2 by not frequency conversion control.
Under different solar radiation, the efficiency of the collector and the air are different. The definition of efficiency is ratio of collector (or air) and solar energy. The test results show that the average solar radiation is 511W/m^2 and it is steady in sometime. The pump and fan are running at full speed, the efficiency of collector can attain 62%, and the efficiency of air is 51%. When the average solar radiation is 790W/m^2 and steady, the pump and fan are running at frequency conversion. The efficiency of collector is 59%, and the efficiency of air is 46%.
Use of frequency conversion control, the pump energy consumption is from 7.7MJ to 2.2MJ by frequency conversion control, and save 71.4 % of pump energy consumption. The fan energy consumption is from 21.2MJ to 5MJ by frequency conversion control, and save 76.4 % of fan energy consumption. It effectively increases the application value.

並列關鍵字

Solar energy ； Vacuum tube ； Collector ； Automatic control

參考文獻

[18]童偉哲，「太陽能輔助噴射製冷系統之最佳效率點追蹤控制研究」，國立台灣大學機械工程學研究所，碩士論文，2011年。

[10]劉耀文，「太陽能真空管式集熱器之流場與熱對流研究」，國立成功大學水利及海洋工程學研究所，碩士論文，2009年。

[5]童開澤，「建築物雙層屋頂整合太陽能空氣集熱器之隔熱與集熱效益研究 ─以鋼板斜屋頂構造為例─」，國立臺北科技大學建築與都市設計研究所，碩士論文，2006年。

[11]吳承駿，「太陽能輔助噴射式製冷系統性能提升研究」，國立台灣大學機械工程學研究所，碩士論文，2011年。

[14]Jiun-Ming Lin, Ming-Po Li, Sheng-Tse Huang, Hung-Yi Liu, Wun-DeLin, and Yi Jwo-Hwu, “Study on a Solar Tracking System: part I:Accuracy of the Formulas,” Proceeding of the 25th symposium on electrical power engineering, pp. 2148-2153, 2004.electrical power engineering, pp. 2148-2153, 2004.