太陽能輔助噴射式製冷系統最佳化控制

Optimal Control of Solar-Assisted Ejector Cooling System

柯華崴(Hua-Wei Ko)

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(2012年)

https://doi.org/10.6342/NTU.2012.10646

摘要

太陽能輔助噴射式製冷系統之運作仰賴許多耗能週邊元件的配合，其中包含各式循環泵浦與冷卻風扇，然而這些元件耗電量往往因過量設計而太大，造成系統整體效率欠佳。本研究整合前人研究：噴射式製冷系統冷媒循環泵浦、太陽能集熱器水循環泵浦之最佳化控制，同時尋找整體系統之最大功率點與最低耗能點，並加以追蹤，以提升太陽能輔助噴射式製冷系統之性能與實際運用價值。
噴射式製冷系統與變頻空調機系統之結合方式一般採用串聯或並聯式，各有其優缺點，本研究嘗試綜合此二種結合方式，成為新的串、並聯複合型系統，可同時發揮兩種系統的優點、使系統性能更進一步提升。
本研究由系統之各元件耗電量進行分析，並找出各元件耗能與可操作參數間之關聯性，各元件中又以冷卻水塔風扇與變頻空調機之耗能最大，推論出所有影響其耗能之變因後，並以多變數函數之擾動觀察實驗證明系統最大價值函數之存在性，並且找出最佳冷卻風扇轉速與膨脹閥開度值，純並聯式系統在冷房溫度不升高之前提下，電能效率值COPe可提升至5.27。進一步設計一包括四種模式的控制系統，視不同條件切換不同模式以發揮噴射器的最佳性能，在外氣溫度37℃下實際測試結果COPe值仍可保持於5.1，大幅提升噴射式系統效能。

關鍵字

太陽能輔助噴射式製冷

並列摘要

The operation of solar-assisted ejector cooling system (SACH system) depends on peripheral equipment, including circulation pumps and cooling fans. However, the power consumption of these devices is considerable because of the over-sized design. And it makes the overall efficiency of ejector cooling system very low. This study integrates former researches and increases the COP of SACH system by tracking the maximum power point of cooling fans and the minimum power consumption point of SACH system. Therefore the overall performance and practical value are successfully improved.
SACH system is composed of ejector cooling system and inverted air conditioner. The traditional combination of these two sub-systems falls into two categories: series combination, and parallel combination. A new hybrid combination which includes series and parallel system is developed. It could improve the system performance by collecting all the advantages of two traditional combinations.
The power consumption of all devices is analyzed and the relationship between the performance and operating factors is found. The existence of maximum power point could be proved by step-up-step-down method. The optimum rotational speed of cooing fans and opening of expansion valve are found. COPe of parallel system could be improved to 5.27. The design of SACH control logic is developed. The logic includes four modes which are distinguished by the different operation states. COPe of hybrid system still beyond 5 at a very high atmosphere temperature (37℃).

並列關鍵字

Solar-Assisted Ejector Cooling

參考文獻

【1】 ASHRAE Equipment Handbook, Stream jet refrigeration equipment, US (1979) 13.1-13.6.

【2】 B.J. Huang, C.B. Jiang, F.L. Hu, Ejector performance characteristics and design analysis of jet refrigeration system, ASME J. Gas Turbine and Power 107 (1985) 792-802.

【3】 B.J. Huang, J.M. Chang, Empirical correlation of ejector design, Int. J. Refrigeration 22 (1999) 379-388.

【4】 B.J. Huang, J.M. Chang, C.P. Wang, V.A. Petrenko, A 1-D analysis of ejector performance, Int. J. Refrigeration 22 (1999) 354-364.

【5】 張俊民，噴射式冷氣系統之研究，台大機械系博士論文(1998).