Assessing the environmental performance of a solar still HDH system: A comparative life cycle study

This study conducts a cradle-to-gate life cycle assessment (LCA) of a solar-powered humidification–dehumidification (HDH) desalination system using OpenLCA 2.5, focusing on two stages: manufacturing and operation. The results show that impacts such as fine particulate matter formation (PMFP), freshwater eutrophication (FEP), and terrestrial acidification (TAP) are mainly driven by the manufacturing phase, largely due to the production process of metals and polymers. Conversely, global warming (GW), fossil resource scarcity (FRP), and several other categories are dominated by the operational stage because of electricity consumption from fossil-fuel-based sources used to power pumps and blowers. Four operational scenarios were evaluated. Scenario 4, which is characterized by enhanced heat and mass transfer through water spraying and the incorporation of phase change materials (PCM), achieved the lowest energy consumption (16.8 kWh/m 3 ) and the best overall environmental performance. Compared to the baseline scenario, it reduced GW by 54%, FRP by 12%, and TAP by 42%. Replacing fossil-based electricity with photovoltaic power reduced CO 2 emissions by 92%, fossil resource scarcity (94%), and other operational emissions. However, some categories, including freshwater ecotoxicity (FETP) and human toxicity (HTPc), increased due to the environmental impacts of photovoltaic panel manufacturing and the extraction of metals and minerals used in their production. Moreover, using recycled materials further reduced GW, FRP, and TAP by 32.9%, 24.1%, and 12.4%, respectively, though HTPc rose by 10% because of toxic additives such as stabilizers and flame retardants used in the recycling process.