Analysis of a multi-stage air gap diffusion distillation system powered by low-grade sensible heat. (5th January 2022)

• Record Type: Journal Article
• Authors: Xu, Shiming; Guo, Sibei; Wu, Xi; Xu, Lin; Wang, Ping; Jin, Dongxu; Wu, Debing; Dong, Fujiang
• Is Part Of: Applied thermal engineering. Volume 200(2022)
• Publication Date: 2022-01-05
• Subjects: Desalination -- Air gap diffusion distillation -- Multi-stage -- Low-grade sensible heat; Heat engineering -- Periodicals; Heating -- Equipment and supplies -- Periodicals; Periodicals; 621.40205
• DOI: 10.1016/j.applthermaleng.2021.117660
• Languages: English
• ISSNs: 1359-4311

Abstract

Highlights: A novel multi-stage AGDD system powered by low-grade sensible heat was proposed. The system could harvest the heat from low-grade sensible heat as much as possible. The freshwater yield of system was significantly affected by feeding seawater flowrates. The freshwater yield of system was notably affected by heat source temperatures. The freshwater yield of system was slightly affected by feeding seawater temperatures. Abstract: A novel multistage air-gap diffusion distillation (MS-AGDD) system powered by low-grade sensible heat (LGSH) was proposed for fully recovering heat from LGSH to produce freshwater. The effect of operating parameter variations on the system performances was investigated theoretically based on the ε- NTU model for AGDD. The operating parameters include the hot water inlet temperature ( T hs in ), the feed seawater flowrate ( V c, n in ), salinity ( S c, n in ) and temperature ( T c, n in ), the temperature differences at the hot end of heat exchanger ( Δ t h ) and at the cold end of coolers ( Δ t c ). Results showed that under the given structure and size parameters of the system and the operating conditions, the variation of T hs in, V c, n in or Δ t h affected the system performances significantly, but the variation of S c, n in or Δ t c affected those relatively less. The total freshwater yield and the recovered heat from the hot water enlarged with the increase of T hs in or V c, n in, but they decreased with the increase of Δ t h . The gained out ratio (GOR) of the system increased with the increase of T hs in, but it decreased with the increase of V c, n in or Δ t h . The irreversibility of the system increased with the increase of T hs in or Δ t h, but it decreased with the increase of T c, n in or V c, n in .