A dual-stage sodium thermal electrochemical converter (Na-TEC) [electronic resource]

• Ngôn ngữ: eng
• Ký hiệu phân loại: 621.312 Generation, modification, storage
• Thông tin xuất bản: Washington, D.C. : Oak Ridge, Tenn. : United States. Dept. of Energy. Office of Energy Efficiency and Renewable Energy ; Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2017
• Mô tả vật lý: Size: p. 217-224 : , digital, PDF file.
• Bộ sưu tập: Metadata
• ID: 255780
• Chủ đề: 1. 14 solar energy; 2. 30 direct energy conversion; 3. 42 engineering; 4. Alkali-metal thermal electric converter (amtec); 5. Beta"-alumina solid-electrolyte (base); 6. Thermally regenerative electrochemical system (tres); 7. Thermo- electro-chemical conversion

Tóm tắt

 We report that the sodium thermal electrochemical converter (Na-TEC) is a heat engine that generates electricity through the isothermal expansion of sodium ions. The Na-TEC is a closed system that can theoretically achieve conversion efficiencies above 45% when operating between thermal reservoirs at 1150 K and 550 K. However, thermal designs have confined previous single-stage devices to thermal efficiencies below 20%. To mitigate some of these limitations, we consider dividing the isothermal expansion into two stages
  one at the evaporator temperature (1150 K) and another at an intermediate temperature (650 K?1050 K). This dual-stage Na-TEC takes advantage of regeneration and reheating, and could be amenable to better thermal management. Herein, we demonstrate how the dual-stage device can improve the efficiency by up to 8% points over the best performing single-stage device. We also establish an application regime map for the single- and dual-stage Na-TEC in terms of the power density and the total thermal parasitic loss. Generally, a single-stage Na-TEC should be used for applications requiring high power densities, whereas a dual-stage Na-TEC should be used for applications requiring high efficiency.