太陽能輔助氣冷式噴射式製冷系統性能最佳化研究

Abstract

噴射式製冷系統串聯空調機，能夠幫助空調機製冷，降低耗電，而噴射式製冷系統所需的熱能可由太陽能集熱器提供，故本研究實驗系統主要包含有三項：太陽能集熱器、空調機與噴射式製冷系統。 一般噴射式製冷系統使用水冷式冷凝器作為散熱機制，因此無法運轉於缺水的氣候條件。本研究對於噴射式製冷系統的硬體改良，成功以氣冷式冷凝器取代了水冷式冷凝器，未來噴射式製冷系統可以自由選擇適合的冷凝器，應用範圍更加廣泛。 針對太陽能驅動之噴射式製冷系統，產生器內的液位控制是最大的考驗。本研究開發出產生器液位控制系統，實驗結果證明可以在不穩定的太陽能中維持固定的產生器液位，使噴射式製冷系統能夠穩定運轉。 噴射式製冷系統的運轉成本不低，主要在冷凝器過於消耗電力。根據噴射器特性，本研究提出了冷凝器壓力最佳化概念，並藉由控制器付諸實行，使冷凝器耗電下降60%，增加了應用價值。

A solar-assisted ejector cooling/heating system (SACH-k1) was developed in the present study. SACH-k1 includes three systems, ejector cooling system, inverter-type air conditioner and solar heating system. The cooling effect of ECS generated by solar heat is used to cool the condenser of the A/C, then increase A/C’s COP and reduce the power consumption of the compressor. It has been noted that ejector cooling system should be designed using an air-cooled condenser in hot climate area because of the water shortage. Thus, SACH-k1 is developed for this purpose and the design details are shown in paper. To utilize solar energy, the liquid level of SACH’s generator needs to be controlled precisely. A liquid level control system is developed in the present study, so that SACH can overcome unstable effect due to generator temperature changes caused by variation of solar irradiation. Further, running cost of ejector cooling system is too high to apply. This study proposes the idea of ejector’s backpressure optimal control and realizes the idea by the optimal control system. As a result, the operating power consumption is decreased about 60%.