太陽能輔助噴射製冷系統之最佳效率點追蹤控制研究

A Study of Optimal Performance Tracking Control for Solar-Assisted Ejector Cooling System

童偉哲(Wei-Che Tung)

指導教授 ： 黃秉鈞

國立臺灣大學/工學院/機械工程學研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.02973

摘要

噴射式製冷系統可由太陽能集熱系統提供熱能，並由水冷式冷凝器散熱，然而週邊耗電過多往往導致系統運轉效能降低，故本研究探討最佳效率點追蹤控制技術以提高噴射式製冷系統運用價值。
傳統強制型太陽能集熱系統常依據標準設計流量選擇泵浦規格，此舉可能造成電能浪費。為了妥善控制泵浦以提升系統效能，本研究提出一個價值函數，並利用擾動觀察法控制實驗證明其存在最大值。然而太陽能集熱器屬於熱流系統存在動態響應問題，本研究先建立集熱系統動態模型，並設計最佳效率點追蹤控制系統。實驗結果證明在追蹤控制器操作下，太陽能集熱系統運轉效能可達125.7，泵浦可省能 78.2%。
由於噴射式製冷系統性能(COPECS)較低，冷凝器散熱量偏高，以至於冷卻塔風扇必須消耗許多電力，本研究依據噴射器性能特性，設計冷卻塔風扇最佳化追蹤控制系統。由實驗結果證明在冷卻塔最佳化控制器操作下，噴射式製冷系統性能(COPECS)可提升23.6 %，風扇耗電可降低至100 W。本研究更進一步整合太陽能輔助噴射式製冷系統於最佳效率點追蹤控制下，總運轉效能(COPe)可達4.5，有效提高應用價值。

關鍵字

太陽能 ； 噴射式製冷 ； 最佳效率點

並列摘要

The ejector cooling system (ECS) could be driven by absorbing heat energy from solar heating system and dissipated heat by water-cooled condenser. However, the power consumption of peripheral equipments is too high to decrease system operating performance. In this study, the optimal performance point tracking control technique is investigated to increase ECS’s application worth.
Traditional forced circulation solar heating system chose the specification of pump according to the standard flow rate. This may result in waste of electricity energy. In order to properly controling the pump and increasing the system performance ,the study attends to proposing a cost function which would be proved existing maximum value by step-up-step-down control test. But the solar collector is a kind of thermal system which existing a problem of dynamic response. At the first, the study finds the system dynamic model, and then designs the optimal performance point tracking control system. The field test results show that the solar heating system’s coefficient of performance could attain 125.7 and save 78.2 % of pump power consumption.
Because the lower COPECS of ECS, the cooling capacity of condenser must be higher, the cooling tower’s fan must consume more electricity power. According to ejector performance property, the study attends to design the optimal control system of cooling tower’s fan. The field test results show that the COPECS could be increased 23.6 % and fan’s power consumption could be reduced to 100 W. Finally, the study integrates the solar assist ejector cooling system with optimal performance point tracking control system. The field test result shows the entire electricity performance, COPe, could attaind 4.5. It effectively increases the application value.

並列關鍵字

Solar heating system ； Ejector ； Optimal performance

參考文獻

【16】 吳佳鴻，噴射式太陽能輔助熱泵製冷供熱系統研究，台灣大學機械系博士論文，2010

【17】 汪金華，熱能輔助熱泵製冷供熱系統研究，台大機械系博士論文(2008)。

【26】 胡勝雄，先進噴射式製冷系統研發，台灣大學機械系博士論文，2005

【3】 M. Kovarik and P. F. Lesse, Optimal control of flow in low temperature solar heat collector, Solar Energy, Vol. 18, pp. 431-435(1976)

【4】 K. H. Hussein, 1EE ploc.-Gener. Transm. Distrib., Vol. 142, No. I, Maximum photovoltaic power tracking: an algorithm for rapidly changing atmospheric conditions, 1995