薄膜蒸餾(Membrane Distillation, MD)是利用一多孔性疏水薄膜，在薄膜兩側提供溫度之差異，藉以因水之蒸汽壓差產生水之傳輸，達到將水純化之目的。太陽輻射所提供之低溫熱源與薄膜蒸餾海水淡化之結合提供了可同時解決能源與水資源不足問題的解決方案。本論文針對太陽能驅動薄膜蒸餾海水淡化系統之動態與控制研究。本研究使用之模式建立於Aspen Custom Modeler(ACM)平台，包括太陽能集熱器、儲熱槽、熱交換器與薄膜蒸餾模組，而後探討系統在不同日照特性下之最適化操作與控制系統設計。 最適化的結果顯示，簡單儲熱槽的配置較複雜之設計理想；薄膜蒸餾模組操作於較低流量有助於產量之提高，但系統之日照吸收量會降低。控制系統之研究顯示，適當的控制器設定點與PI控制器諧調，有助於系統之整體性能。 Membrane distillation is a feasible technology for desalination by utilizing the vapor pressure difference across a hydrophobic membrane via temperature driving force. The integration of the low-temperature solar thermal energy with the membrane distillation provides a way to simultaneously solving the energy and water resource problems. The thesis investigates the dynamics and control of the solar powered membrane distillation desalination systems. A system simulation model is built on Aspen Custom Modeler platform, including models for solar collector, thermal storage tank, heat exchanger and membrane distillation module. The model is then used for the dynamic optimization and control system design under different solar radiation conditions. The optimization study reveals that simple thermal storage tank configuration is better than other complex configurations. Besides, the operation using lower flow rate in the membrane distillation module helps the freshwater production but sacrifices the thermal energy absorption. Appropriate controller set points and PI controller tunings can benefit the system performance.
