Abstract
According to United Nations data, half of the world’s population lives in cities and forecasts indicate that by the middle of the 21st century, this percentage will have increased to 65%. The increase in the urban population favors the creation of a network of interactions that entails a series of material and energy flows. These cause environmental impacts that affect the quality of life of citizens and the environment as a whole. According to data from the International Energy Agency, cities occupy 3% of the planet’s surface and are responsible for 67% of global energy consumption. The effects caused by this consumption, as well as its impact on the depletion of resources, make it necessary to carry out an exhaustive study of renewable energies and new energy saving systems. This Special Issue aims to present new advances and developments in renewable energy and energy saving systems that allow cities to evolve in a sustainable way.
1. Introduction
The world is becoming increasingly urbanized. Since 2007, more than half of the world’s population has been living in cities, and according to the UN, that number is expected to rise to 60% by 2030 [1]. Faced with this critical situation, the UN landed the 17 objectives that make up the so-called Sustainable Development Goals. These are 17 ambitious proposals to combat the world’s major problems, such as poverty, climate change, inequality and the environment, among others.
Making cities and human settlements inclusive, safe, resilient and sustainable is Sustainable Development Goal 11 in the UN 2030 Agenda on Sustainable Development [1]. However, to achieve this goal, the following four fundamental aspects need to be taken into account [2]:
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- Social development;
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- Economic growth;
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- Environmental protection;
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- Institutional dimension.
According to Kennedy, Cuddihy and Engel-Yan (2007), a sustainable city would be one in which the input of material and energy resources and the disposal of waste do not exceed the capacity of the surrounding environment [3]. In order to achieve sustainability, cities face the following challenges:
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- Reduce CO2 emissions;
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- Use energy efficiency and renewable energy sources;
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- Generate and maintain green spaces in cities;
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- Encourage urban mobility and public transport among citizens.
This Special Issue aims to present new advances and developments in renewable energy and energy saving systems that allow cities to evolve in a sustainable way.
Abdallah et al. conducted a review of the state of the art on Recycling Composite Waste Using Pyrolysis for Sustainable Development [4].
Ramez Abdallah et al. developed a simple neural network model to predict the annual radiation and estimate the optimum tilt angles for (PV) panels for all countries worldwide [5].
Aiman Albatayneh et al. compared different buildings that had undergone facade retrofitting to increase thermal comfort, such as increasing the external insulation layer and replacing window glazing or shading. The results show significant energy savings in the different buildings [6].
Aiman Albatayneh et al. studied the impact of more efficient lighting systems on the optimal windows-to-wall ratio of typical residential buildings in Jordan [7].
Enríquez Santiago et al. developed a methodology where three optimum permanent magnet synchronous generators (PMSGs) dimensions and several options that can be defined by the user from the maximum efficiency optimized PMSG to the minimum weight optimized PMSG were obtained [8].
2. Publication Statistics
Table 1 shows a summary of the number of authors who participated in this Special Issue and their country of origin according to their affiliation. A total of 22 authors from seven countries have contributed scientific studies related to the sustainability of cities.
Table 1.
Authors’ countries.
3. Authors’ Affiliations
Table 2 shows the affiliation of the 22 authors who participated in this Special Issue. For statistical purposes, only the first affiliation of each author has been considered.
Table 2.
Authors’ affiliations.
4. Topics
Table 3 shows the topics of the different scientific studies carried out on the sustainability of cities.
Table 3.
Topics of the Sustainable city.
Author Contributions
Conceptualization, A.-J.P.-M. and Q.H.-E.; methodology, A.-J.P.-M. and Q.H.-E.; validation, A.-J.P.-M. and Q.H.-E.; formal analysis, A.-J.P.-M. and Q.H.-E.; writing—review and editing, A.-J.P.-M. and Q.H.-E. All authors have read and agreed to the published version of the manuscript.
Funding
This research received no external funding.
Institutional Review Board Statement
Not applicable.
Informed Consent Statement
Not applicable.
Data Availability Statement
Not applicable.
Acknowledgments
The authors would like to thank the University of Córdoba and the National Autonomous University of Mexico for their support.
Conflicts of Interest
The authors declare no conflict of interest.
References
- Naciones Unidas. Ciudades—Desarrollo Sostenible. Available online: https://www.un.org/sustainabledevelopment/es/cities/ (accessed on 20 October 2021).
- United Nations. World Economic and Social Survey 2013: Sustainable Development Challenges; United Nations Publication: New York, NY, USA, 2013; Available online: https://www.un.org/en/development/desa/policy/wess/wess_current/wess2013/WESS2013.pdf (accessed on 18 October 2021).
- Kennedy, C.; Cuddihy, J.; Engel-Yan, J. The Changing Metabolism of Cities. J. Ind. Ecol. 2007, 11, 43–59. [Google Scholar] [CrossRef] [Scilit]
- Abdallah, R.; Juaidi, A.; Savaş, M.A.; Çamur, H.; Albatayneh, A.; Abdala, S.; Manzano-Agugliaro, F. A Critical Review on Recycling Composite Waste Using Pyrolysis for Sustainable Development. Energies 2021, 14, 5748. [Google Scholar] [CrossRef] [Scilit]
- Abdallah, R.; Natsheh, E.; Juaidi, A.; Samara, S.; Manzano-Agugliaro, F. A Multi-Level World Comprehensive Neural Network Model for Maximum Annual Solar Irradiation on a Flat Surface. Energies 2020, 13, 6422. [Google Scholar] [CrossRef] [Scilit]
- Albatayneh, A.; Jaradat, M.; AlKhatib, M.B.; Abdallah, R.; Juaidi, A.; Manzano-Agugliaro, F. The Significance of the Adaptive Thermal Comfort Practice over the Structure Retrofits to Sustain Indoor Thermal Comfort. Energies 2021, 14, 2946. [Google Scholar] [CrossRef] [Scilit]
- Albatayneh, A.; Juaidi, A.; Abdallah, R.; Manzano-Agugliaro, F. Influence of the Advancement in the LED Lighting Technologies on the Optimum Windows-to-Wall Ratio of Jordanians Residential Buildings. Energies 2021, 14, 5446. [Google Scholar] [CrossRef] [Scilit]
- Santiago, J.A.E.; Danguillecourt, O.L.; Duharte, G.I.; Díaz, J.E.C.; Añorve, A.V.; Hernandez Escobedo, Q.; Enríquez, J.P.; Verea, L.; Galvez, G.H.; Portela, R.D.; et al. Dimensioning Optimization of the Permanent Magnet Synchronous Generator for Direct Drive Wind Turbines. Energies 2021, 14, 7106. [Google Scholar] [CrossRef] [Scilit]
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