상세정보

Low-grade thermal energy is abundant but difficult to use due to limited energy availability. Recently, research on low-grade thermal energy has been carried out in order to improve energy availability. One of these methods has been proposed: pressure-retarded membrane distillation (PRMD). It was created by fusing the principles of membrane distillation and pressure-retarded osmosis. In this paper, a closed-loop PRMD with thermo-osmotic energy conversion (TOEC) structure is proposed to enable simultaneous desalination and power generation. To assess the feasibility of a new process, MATLAB is used for mathematical modeling and energetic/exergetic analyses. In addition, a sensitivity analysis is performed to assess the process's energy efficiency. The results show that, when compared to existing processes, the closed-loop PRMD system requires the least amount of heat (35.9 kW) and produces the most electrical energy (39.33 W) to achieve the same water permeation. Furthermore, unlike the TOEC process, water and electrical energy can be produced concurrently. Furthermore, the closed-loop PRMD is found to have the lowest exergy destruction. As a result, the proposed closed-loop PRMD is a promising solution for desalination and low-grade thermal energy harvesting systems.

1. Introduction   1
2. Methods and modeling   5
 2.1. Process description of the closed-loop PRMD   5
 2.2. Mathematical modeling   12
  2.2.1 Mass transfer   12
  2.2.2 Heat transfer   14
  2.2.3 Liquid entry pressure   17
  2.2.4 Balance equations   18
 2.3. Energy and exergy models   19
  2.3.1 Heat exchanger design   20
  2.3.2 Electric energy model   21
  2.3.3 Exergy model   22
 2.4. Algorithm   24
 2.5. Operating conditions and simulation parameters   27
3. Results and discussion   30
 3.1. Performance analysis of the closed-loop PRMD   30
  3.1.1. Effects of membrane compaction   30
  3.1.2. Effects of operating conditions   33
  3.1.3. Effects of membrane parameters   36
 3.2. Comparison of performances in open-loop PRMD, TOEC, and closed-loop PRMD systems   42
  3.2.1. Energy generation and freshwater production   42
  3.2.2. Exergetic analysis   47
 3.3. Implications of closed-loop PRMD's future potential   51
4. Conclusions   53
References   55