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14 pages, 3839 KiB

Open AccessArticle

Three-Dimensional Double-Layer Multi-Stage Thermal Management Fabric for Solar Desalination

by Xiao Feng, Can Ge, Heng Du, Xing Yang and Jian Fang

Materials 2024, 17(17), 4419; https://doi.org/10.3390/ma17174419 - 7 Sep 2024

Cited by 1 | Viewed by 1708

Water scarcity is a serious threat to the survival and development of mankind. Interfacial solar steam generation (ISSG) can alleviate the global freshwater shortage by converting sustainable solar power into thermal energy for desalination. ISSG possesses many advantages such as high photothermal efficiency, robust durability, and environmental friendliness. However, conventional evaporators suffered from huge heat losses in the evaporation process due to the lack of efficient thermal management. Herein, hydrophilic Tencel yarn is applied to fabricate a three-dimensional double-layer fabric evaporator (DLE) with efficient multi-stage thermal management. DLE enables multiple solar absorptions, promotes cold evaporation, and optimizes thermal management. The airflow was utilized after structure engineering for enhanced energy evaporation efficiency. The evaporation rate can reach 2.86 kg·m⁻²·h⁻¹ under 1 sun (1 kW·m⁻²), and 6.26 kg·m⁻²·h⁻¹ at a wind speed of 3 m·s⁻¹. After a long duration of outdoor operation, the average daily evaporation rate remains stable at over 8.9 kg·m⁻², and the removal rate of metal ions in seawater reaches 99%. Overall, DLE with efficient and durable three-dimensional multi-stage thermal management exhibits excellent practicality for solar desalination. Full article

(This article belongs to the Special Issue Properties of Textiles and Fabrics and Their Processing)

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21 pages, 2583 KiB

Open AccessArticle

Energy Saving Analysis of a Marine Main Engine during the Whole Voyage Utilizing an Organic Rankine Cycle System to Recover Waste Heat

by Wu Chen, Song Xue, Long Lyu, Wenhua Luo and Wensheng Yu

J. Mar. Sci. Eng. 2023, 11(1), 103; https://doi.org/10.3390/jmse11010103 - 4 Jan 2023

Cited by 6 | Viewed by 2806

Abstract

In this study, a main marine engine with a rating power of 21,840 kW for a ship sailing in an actual voyage was obtained as the research object. The engine’s exhaust gas and jacket cooling water were adopted as the heat source of the organic Rankine cycle (ORC) system developed for the main marine engine. The engine can consume high-sulfur or low-sulfur fuel oil, respectively, according to the different emission control requirements. The impact of the use of high-sulfur or low-sulfur fuel oil, and variations in engine load, amount of recoverable waste heat, outboard seawater temperature, and the ship’s steam demand were comprehensively considered, and the validated ORC system model was used for the analysis of the system’s performance and the ship’s energy saving for the whole voyage. The results demonstrated that when the ship adopted high-sulfur or low-sulfur fuel oil, the maximum total net power output of the ORC system was 449.3 kW and 753.1 kW, respectively. During the whole voyage of 1610.7 nautical miles, when high-sulfur fuel oil was used, the ORC system reduced carbon emission by 40.3 tons and 33.8 tons, respectively, in summer and in winter, and the fuel saving rates were 2.53% and 2.12%; when low-sulfur fuel oil was used, the ship’s carbon emissions were reduced by 62.1 tons and 61.8 tons, respectively, in summer and in winter, and the fuel saving rates were 3.91% and 3.89%. Full article

(This article belongs to the Section Ocean Engineering)

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12 pages, 2169 KiB

Open AccessArticle

Nanocomposite-Enhanced Efficient Evaporation System for Solar-Driven Seawater Desalination—An Optimized Design for Clean Water Production

by Zhou Wei, Muhammad Sultan Irshad, Naila Arshad, Laila Noureen, Iftikhar Ahmed, Naveed Mushtaq, Muhammad Sohail Asghar, Qaisar Hayat, Uzma Ghazanfar, Muhammad Idrees, Naeem Shahzad and Yuzheng Lu

Nanomaterials 2022, 12(19), 3296; https://doi.org/10.3390/nano12193296 - 22 Sep 2022

Cited by 4 | Viewed by 4686

Abstract

Solar-driven evaporation is a promising technology for desalinating seawater and wastewater without mechanical or electrical energy. The approaches to obtaining fresh water with higher evaporation efficiency are essential to address the water-scarcity issue in remote sensing areas. Herein, we report a highly efficient solar evaporator derived from the nanocomposite of anatase TiO₂/activated carbon (TiO₂/AC), which was coated on washable cotton fabric using the dip-dry technique for solar water evaporation. The ultra-black fabric offers enhanced solar absorption (93.03%), hydrophilic water transport, and an efficient evaporation rate of 1.65 kg/m²h under 1 kW m⁻² or one sun solar intensity. More importantly, the sideways water channels and centralized thermal insulation of the designed TiO₂/AC solar evaporator accumulated photothermal heat at the liquid and air interface along with an enhanced surface temperature of 40.98 °C under one sun. The fabricated solar evaporator desalinated seawater (3.5 wt%) without affecting the evaporation rates, and the collected condensed water met the standard of drinking water set by the World Health Organization (WHO). This approach eventually enabled the engineering design groups to develop the technology pathways as well as optimum conditions for low-cost, scalable, efficient, and sustainable solar-driven steam generators to cope with global water scarcity. Full article

(This article belongs to the Special Issue Nanostructured Materials for Energy Applications)

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24 pages, 3684 KiB

Open AccessArticle

A Concept for Solving the Sustainability of Cities Worldwide

by Karmen Margeta, Zvonimir Glasnovic, Nataša Zabukovec Logar, Sanja Tišma and Anamarija Farkaš

Energies 2022, 15(2), 616; https://doi.org/10.3390/en15020616 - 16 Jan 2022

Cited by 5 | Viewed by 2591

Abstract

Considering that more than half of the world’s population today lives in cities and consumes about 80% of the world’s energy and that there is a problem with drinking water supply, this paper presents a way to solve the problem of the sustainability of cities by enabling their complete independence from external sources of energy and drinking water. The proposed solution entails the use of Seawater Steam Engine (SSE) technology to supply cities with electricity, thermal energy and drinking water. The system would involve the seasonal storage of electricity and thermal energy, supported by geothermal heat pumps. The strategy of the distribution network would be based on the original concept of the “loop”. In cities that do not have enough space, SSE collectors would be placed above the lower parts of the city like “canopies”. The city of Zagreb (Croatia) was selected as a case study due to its size, climate and vulnerability to natural disasters. The results show that Zagreb could become sustainable in 30 years with the allocation of less than 2% of GDP and could become a paradigm of sustainability for cities worldwide. This paper encourages the development of the “Philosophy of Sustainability” because the stated goals cannot be achieved without a change in consciousness. Full article

(This article belongs to the Special Issue Green Economy and Sustainable Development)

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32 pages, 6764 KiB

Open AccessArticle

Humanity Can Still Stop Climate Change by Implementing a New International Climate Agreement and Applying Radical New Technology

by Zvonimir Glasnovic, Karmen Margeta and Nataša Zabukovec Logar

Energies 2020, 13(24), 6703; https://doi.org/10.3390/en13246703 - 18 Dec 2020

Cited by 4 | Viewed by 5988

Abstract

There is a broad consensus worldwide that anthropogenic climate change is a scientific fact. Likewise, the fact is that the UN’s efforts to address climate change over the last 28 years have not been successful enough. It is evident that the global average temperature is on the rise (1.1 °C above pre-industrial levels in 2019). A particular concern comes from the fact that the Paris Agreement on keeping increases in the global average temperature to below +2 °C is an unenforceable ambition, since the focus is more on consequences than causes. In addition, economic policies regarding global taxes, as well as adaptation and mitigation measures, are questionable, as there is no evidence that changes in the climate system will proceed at the same rate in the coming years. This paper proposes an engineering approach that considers all relevant aspects of the climate change problem and proposes a new policy, named the “Climate New Deal”. It deals with: (i) Reorientation from a high-carbon economy to a green economy; (ii) The intensive use of radically new technology, e.g., “Seawater Steam Engine” technology for the simultaneous production of thermal and electric energy and drinking water; and (iii) The intensive use of energy efficient technologies and RES technologies, especially in transport. Full article

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