Osmotic engine converting energy from salinity difference to a hydraulic accumulator by utilizing polyelectrolyte hydrogels. (1st October 2021)

• Record Type: Journal Article
• Authors: Bui, Tri Quang; Magnussen, Ole-Petter; Cao, Vinh Duy; Wang, Wei; Kjøniksen, Anna-Lena; Aaker, Olav
• Is Part Of: Energy. Volume 232(2021)
• Publication Date: 2021-10-01
• Subjects: Osmotic engine -- Salinity gradient -- Energy transmission -- Hydrogel; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Energy consumption -- Periodicals; 333.7905
• DOI: 10.1016/j.energy.2021.121055
• Languages: English
• ISSNs: 0360-5442

Abstract

Abstract: Efficient harvesting of the mixing energy from the salinity gradient between sea and river water remains a challenge. Recently, utilization of the swelling/shrinking properties of hydrogels has been explored as a new means for extracting this energy. However, former investigations are mainly limited to examining the performance of the hydrogels when lifting applied weights, and calculating the energy that could potentially be extracted. In this study, we demonstrate a novel osmotic engine with a mechanical energy transmission prototype, which can convert and store the green mixing energy in a form that can be utilized to perform mechanical work. The osmotic engine includes a cylinder containing the hydrogel, an oil-hydraulic cylinder and a hydraulic accumulator. The lifting energy from the hydrogel is transferred to the oil-hydraulic cylinder through a lever, which acts as a pump and accumulate the hydraulic oil under high pressure in the hydraulic accumulator. The system was tested with a hydrogel of poly(acrylic acid) semi-interpenetrated with poly(4-styrenessulfonic acid- co -maleic acid) sodium. This hydrogel produced up to 36 J per shrinking/swelling cycle, and exhibited an efficiency of 0.53% at optimum conditions. Highlights: Hydrogels was utilized to extract salinity gradient energy. A scaled-up osmotic engine for was constructed. The energy can be stored in a hydraulic accumulator.