Solar Energy Applications in Houses, Smart Cities and Microgrids

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Energy Science and Technology".

Deadline for manuscript submissions: closed (30 June 2019) | Viewed by 19856

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Department of Agricultural and Forestry Engineering, University of Valladolid, Campus Duques de Soria, 42004 Soria, Spain
Interests: energy; engineering; computer science; photovoltaic systems; microgrids; distributed generation; smart metering
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Special Issue Information

Dear Colleagues,

This Special Issue aims to present the reality of renewable energy sources, specifically those based on solar energy. This reality focuses on the integration of solar energy in cities (Smart Cities), buildings (Smart Buildings), microgrids, smart Rural Grids, and other similar environments. The applicability of solar energy is fundamental for the sustainable development of the previous infrastructures. Therefore, the topics of interest of this Special Issue are as follows:

  1. The integration of photovoltaic systems in cities, buildings, and microgrids.
  2. The hybridization of photovoltaic systems with electrical storage.
  3. The hybridization of photovoltaic systems with other energy sources.
  4. Monitoring tools for systems based on solar energy.
  5. Tools to improve efficiency in systems based on solar energy.
  6. The integration of thermal systems in cities, buildings, and microgrids.
  7. The prediction of solar resources for the estimation of small-scale photovoltaic production.
  8. Artificial Intelligence applied to the management and operation of solar systems.

Prof. Dr. Luis Hernández-Callejo
Guest Editor

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Keywords

  • photovoltaic systems
  • thermal systems
  • artificial intelligence
  • monitoring and operation

Published Papers (5 papers)

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Research

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13 pages, 4310 KiB  
Article
Simulation of a Solar-Assisted Air-Conditioning System Applied to a Remote School
by Jesús Armando Aguilar-Jiménez, Nicolás Velázquez, Ricardo López-Zavala, Luis A. González-Uribe, Ricardo Beltrán and Luis Hernández-Callejo
Appl. Sci. 2019, 9(16), 3398; https://0-doi-org.brum.beds.ac.uk/10.3390/app9163398 - 18 Aug 2019
Cited by 12 | Viewed by 3688
Abstract
In this work, we present an absorption cooling system with 35 kW capacity driven by solar thermal energy, installed in the school of Puertecitos, Mexico, an off-grid community with a high level of social marginalization. The cooling system provides thermal comfort to the [...] Read more.
In this work, we present an absorption cooling system with 35 kW capacity driven by solar thermal energy, installed in the school of Puertecitos, Mexico, an off-grid community with a high level of social marginalization. The cooling system provides thermal comfort to the school’s classrooms through four 8.75-kW cooling coils, while a 110-m2 field of evacuated tube solar collectors delivers the thermal energy needed to activate the cooling machine. The characteristics of the equipment installed in the school were used for simulation and operative analysis of the system under the influence of typical factors of an isolated coastal community, such as the influence of climate, thermal load, and water consumption in the cooling tower, among others. The aim of this simulation study was to determine the best operating conditions prior to system start-up, to establish the requirements for external heating and cooling services, and to quantify the freshwater requirements for the proper functioning of the system. The results show that, with the simulated strategies implemented, with a maximum load operation, the system can maintain thermal comfort in the classrooms for five days of classes. This is feasible as long as weekends are dedicated to raising the water temperature in the thermal storage tank. As the total capacity of the system is distributed in the four cooling coils, it is possible to control the cooling demand in order to extend the operation periods. Utilizing 75% or less of the cooling capacity, the system can operate continuously, taking advantage of stored energy. The cooling tower requires about 750 kg of water per day, which becomes critical given the scarcity of this resource in the community. Full article
(This article belongs to the Special Issue Solar Energy Applications in Houses, Smart Cities and Microgrids)
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11 pages, 2508 KiB  
Article
Thermal Evaluation of Graphene Nanoplatelets Nanofluid in a Fast-Responding HP with the Potential Use in Solar Systems in Smart Cities
by M. M. Sarafraz, Iskander Tlili, Zhe Tian, Mohsen Bakouri, Mohammad Reza Safaei and Marjan Goodarzi
Appl. Sci. 2019, 9(10), 2101; https://0-doi-org.brum.beds.ac.uk/10.3390/app9102101 - 22 May 2019
Cited by 65 | Viewed by 3485
Abstract
An experimental study was undertaken to assess the heat-transfer coefficient (HTC) of graphene nanoplatelets-pentane nanofluid inside a gravity-assisted heat pipe (HP). Influence of various parameters comprising heat flux, mass fraction of the nanoparticles, installation angle and filling ratio (FR) of the working fluid [...] Read more.
An experimental study was undertaken to assess the heat-transfer coefficient (HTC) of graphene nanoplatelets-pentane nanofluid inside a gravity-assisted heat pipe (HP). Influence of various parameters comprising heat flux, mass fraction of the nanoparticles, installation angle and filling ratio (FR) of the working fluid on the HTC of the HP was investigated. Results showed that the HTC of the HP was strongly improved due to the presence of the graphene nanoplatelets. Also, by enhancing the heat flux, the HTC of the HP was improved. Two trade-off behaviors were identified. The first trade-off belonged to the available space in the evaporator and the heat-transfer coefficient of the system. Another trade-off was identified between the installation angle and the residence time of the working fluid inside the condenser unit. The installation angle and the FR of the HP were identified in which the HTC of the HP was the highest. The value of installation angle and filling ratio were 65° and 0.55, respectively. Likewise, the highest HTC was obtained at the largest mass fraction of the graphene nanoplatelets which was at wt. % = 0.3. The improvement in the HTC of the HP was ascribed to the Brownian motion and thermophoresis effects of the graphene nanoplatelets. Full article
(This article belongs to the Special Issue Solar Energy Applications in Houses, Smart Cities and Microgrids)
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17 pages, 4968 KiB  
Article
Potential of Solar Collectors for Clean Thermal Energy Production in Smart Cities using Nanofluids: Experimental Assessment and Efficiency Improvement
by M. M. Sarafraz, Iskander Tlili, Mohammad Abdul Baseer and Mohammad Reza Safaei
Appl. Sci. 2019, 9(9), 1877; https://0-doi-org.brum.beds.ac.uk/10.3390/app9091877 - 07 May 2019
Cited by 67 | Viewed by 4494
Abstract
In this article, an experimental study was performed to assess the potential thermal application of a new nanofluid comprising carbon nanoparticles dispersed in acetone inside an evacuated tube solar thermal collector. The effect of various parameters including the circulating volumetric flow of the [...] Read more.
In this article, an experimental study was performed to assess the potential thermal application of a new nanofluid comprising carbon nanoparticles dispersed in acetone inside an evacuated tube solar thermal collector. The effect of various parameters including the circulating volumetric flow of the collector, mass fraction of the nanoparticles, the solar irradiance, the tilt angle and the filling ratio values of the heat pipes on the thermal performance of the solar collector was investigated. It was found that with an increase in the flow rate of the working fluid within the system, the thermal efficiency of the system was improved. Additionally, the highest thermal performance and the highest temperature difference between the inlet and the outlet ports of the collector were achieved for the nanofluid at wt. % = 0.1. The best tilt angle and the filling ratio values of the collector were 30° and 60% and the maximum thermal efficiency of the collector was 91% for a nanofluid at wt. % = 0.1 and flow rate of 3 L/min. Full article
(This article belongs to the Special Issue Solar Energy Applications in Houses, Smart Cities and Microgrids)
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22 pages, 5355 KiB  
Article
Impedance Measurement and Detection Frequency Bandwidth, a Valid Island Detection Proposal for Voltage Controlled Inverters
by Marc Llonch-Masachs, Daniel Heredero-Peris, Cristian Chillón-Antón, Daniel Montesinos-Miracle and Roberto Villafáfila-Robles
Appl. Sci. 2019, 9(6), 1146; https://0-doi-org.brum.beds.ac.uk/10.3390/app9061146 - 18 Mar 2019
Cited by 8 | Viewed by 2885
Abstract
Anti-islanding detection methods have been part of a secure operation for distributed energy resource inverters, avoiding the creation of non-intentional energization when the mains are lost. These detection mechanisms were conceived historically for current-controlled inverters. New control possibilities have broken ground, and current- [...] Read more.
Anti-islanding detection methods have been part of a secure operation for distributed energy resource inverters, avoiding the creation of non-intentional energization when the mains are lost. These detection mechanisms were conceived historically for current-controlled inverters. New control possibilities have broken ground, and current- or voltage-controlled inverters are a reality; however, special attention must be paid to detection strategies when applied to the latter ones. This paper addresses two topics: it exposes the lack of effectiveness of those detection algorithms based on the voltage/frequency displacement concept under voltage-controlled inverters and evaluates the applicability limits of the others based on the impedance measurement (IM). The IM is presented as a valid mechanism to achieve the islanding detection, but the exploration of its limits drives the concept of detection frequency bandwidth (DFBW), introduced in this paper. The DFBW is suggested as a practical approach to select the proper injection frequency to measure. Therefore, an improved strategy based on the IM and DFBW is proposed to allow achieving the detection towards (non-)resonant loads considering low computational burden. The results were experimentally validated in a 90-kVA four-wire voltage-controlled inverter, offering detection times of less than 100 ms in any case. Full article
(This article belongs to the Special Issue Solar Energy Applications in Houses, Smart Cities and Microgrids)
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Review

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21 pages, 7235 KiB  
Review
Contribution of Smart Cities to the Energy Sustainability of the Binomial between City and Country
by Manuel Villa-Arrieta and Andreas Sumper
Appl. Sci. 2019, 9(16), 3247; https://0-doi-org.brum.beds.ac.uk/10.3390/app9163247 - 08 Aug 2019
Cited by 7 | Viewed by 4143
Abstract
Cities are at the center of the transition to a decarbonized economy. The high consumption of electricity in these urban areas causes them to be the main focus of greenhouse gas emissions. However, they have a high margin of capacity to increase energy [...] Read more.
Cities are at the center of the transition to a decarbonized economy. The high consumption of electricity in these urban areas causes them to be the main focus of greenhouse gas emissions. However, they have a high margin of capacity to increase energy efficiency and local energy generation. Along these lines, the smart urban management model has been proposed as a solution to the unsustainability of cities. Due to the global trend of population concentration in urban areas, cities tend to be representative of the population, energy consumption, and energy sustainability of their countries. Based on this hypothesis, this paper studied the relationship between the smart city model and the concept of energy sustainability. First, the research analyzed the relationship between urban population growth and energy sustainability; and then the self-consumption capacity of photovoltaic electricity of the main cities of the countries classified in the energy sustainability indicator (Energy Trilemma Index 2017) of the World Energy Council was analyzed. According to the results, the scope of action for self-consumption of photovoltaic electricity is broad and cities have the capacity to contribute significantly to the energy sustainability of their countries. Following the approach of other authors, the development of energy sustainability objectives and the installation of smart systems in distribution grids must be aligned with national objectives. Full article
(This article belongs to the Special Issue Solar Energy Applications in Houses, Smart Cities and Microgrids)
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