The potential of waste heat utilization in solar multistage membrane distillation : an alternative to PV + RO systems?

Poredoš, Primož (author), Gao, Jintong (author), Ali, Abdallah Yousef Mohammed (author), Shan, He (author), Xu, Zhenyuan (author), Zavrl, Eva (author), Žižak, Tej (author), Trajkovski, Dejan (author), Arkar, Ciril (author), Wang, Ruzhu (author)

Solar membrane distillation (MD) is an emerging technology for addressing water scarcity in arid regions with access to terrestrial water bodies. Recent studies highlight that vaporization enthalpy recycling enhances both distillate flux and solar-to-water efficiency. However, due to high material costs, scaling beyond 10 stages under one-sun solar illumination becomes economically unfeasible. A novel waste heat utilization concept for continuous freshwater production is introduced, supported by a generalized Python-based mathematical model and COMSOL Multiphysics simulations that consider simultaneous heat and moisture transfer. The findings highlight the potential of low-grade waste heat to enhance the efficiency of MD processes. With a solar-to-waste heat ratio of 0.4, a 9-stage MD system can match PV + RO water production per exergy use (36.2 L kWh▫$^{-1}$▫), while even a 3-stage MD system operating solely on waste heat surpasses PV + RO performance. This highlights the importance of cross-sectoral integration, where polygeneration, water, and electricity production play a key role. Techno-economic analysis indicates that such a system in Spain could achieve a 6-year payback period, reinforcing its potential as a competitive alternative to PV + RO for freshwater production. This work contributes to UN Sustainable Development Goals 6 and 7 (SDG-6, SDG-7), promoting clean water, sanitation, and sustainable energy solutions.

• Language: English
• Keywords: membranska destilacija, solarna energija, fototermalni materiali, management voda, energetska učinkovitost, matematični model, prenos toplote in snovi, COMSOL Multiphysics simulacije
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2025
• Number of pages: 18 str.
• Numbering: Vol. 341, art. 119977
• PID: 20.500.12556/RUL-170833
• UDC: 621
• ISSN on article: 1879-2227
• DOI: 10.1016/j.enconman.2025.119977
• COBISS.SI-ID: 242895619
• Publication date in RUL: 17.07.2025

Record is a part of a journal

• Title: Energy conversion and management
• Publisher: Elsevier
• ISSN: 1879-2227
• COBISS.SI-ID: 23208709

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: membrane distillation, solar energy, photothermal materials, water management, energy efficiency, mathematical model, heat and mass transfer, COMSOL Multiphysics simulations