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Renewable Energy Technologies for Small Scale Applications

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A special issue of Energies (ISSN 1996-1073).

Deadline for manuscript submissions: closed (30 June 2016) | Viewed by 63896

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Prof. Dr. Maurizio Sasso

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Guest Editor

Department of Engineering, University of Sannio, 82100 Benevento, Italy
Interests: energy efficiency; geothermal energy; exergy analysis; microcogeneration; energy communities; gas-engine dirven heat pump; thermoeconomic optimization; dessicant-based HVAC system
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Prof. Dr. Carlo Roselli

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Guest Editor

DING, Department of Engineering, University of Sannio, 82100 Benevento, Italy
Interests: energy efficiency; geothermal energy; exergy analysis; microcogeneration; energy communities; gas-engine-driven heat pump; thermoeconomic optimization; desiccant-based HVAC system
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The attention of governments and communities to energy and environmental issues, the need for decarbonization and denuclearization to reduce pollution, the risks of disasters, and the growing awareness of the positive economic and social impact of renewable energy driven systems are the main reasons that, nowaday, there is support for the massive diffusion of renewable energy technologies.

The purpose of this Special Issue is to collect recent, interesting, and original studies that demonstrate energy, environmental, economic and social benefits derived from the proper installation and operation of small scale renewable systems in industrialized and developing areas.

The complexity of renewable energy convertion systems, their management, and optimization, considering the bidirectional interaction with external energy networks and coupling with conventional fossil fuel-based energy devices are the main challenges that research needs to face in order to support their diffusion.

Furthermore, the ongoing transition from centralized to distributed generation systems is sustained by the commercialization of small-scale energy conversion systems for residential and light commercial applications, based on both fossil fuels and renewable sources. However, the miniaturization of energy-conversion devices often leads to an efficiency reduction (due to the so-called “size effect”), and this obviously has a negative effect on energy, economic, and emission performance of distributed generators.

As stated above, papers that analyze renewable energy technologies for small-scale applications on the basis of one or some of the following topics are welcome in this Special Issue:

Energy, environmental, and economic analysis of renewable energy technologies;
Reduction of interactions with external energy networks (electric grid, district heating and cooling), self-consuming;
Community-scale solutions;
Improving the social acceptability of renewable energy technologies;
Integration with electric vehicles;
Economic support mechanisms and regulation;
Interchange of electric, thermal and cooling loads (load sharing).

The above list is not exhaustive, and, in any case, works on areas not listed, but interesting for the Special Issue, are invited.

Prof. Dr. Maurizio Sasso
Prof. Dr. Carlo Roselli
Guest Editors

Manuscript Submission Information

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Keywords

Small Scale Applications
Renewable Energy
Solar Heating and Cooling
Photovoltaic
Micro-Wind Power
Small Hydro Power
Geothermal Energy
Ground Source Heat Pumps
Biomass
Energy Networks
Optimized Management

Published Papers (10 papers)

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Research

1977 KiB

Open AccessArticle

Biomass Residues to Renewable Energy: A Life Cycle Perspective Applied at a Local Scale

by Esmeralda Neri, Daniele Cespi, Leonardo Setti, Erica Gombi, Elena Bernardi, Ivano Vassura and Fabrizio Passarini

Energies 2016, 9(11), 922; https://doi.org/10.3390/en9110922 - 08 Nov 2016

Cited by 34 | Viewed by 6036

Abstract

Italy, like every country member of the European Union (EU), will have to achieve the objectives required by the Energy Roadmap 2050. The purpose of the study was to evaluate the environmental impacts of residue recovery arising from the management of public and private green feedstocks, activity of the cooperative “Green City” in the Bologna district, and usage in a centralized heating system to produce thermal energy for public buildings. Results, obtained using the ReCipe impact assessment method, are compared with scores achieved by a traditional methane boiler. The study shows some advantages of the biomass-based system in terms of greenhouse gases (GHGs) emissions and consumption of non-renewable fuels, which affect climate change (−41%) and fossil resources depletion (−40%), compared to the use of natural gas (NG). Moreover, scores from network analysis denote the great contribution of feedstock transportation (98% of the cumulative impact). The main reason is attributable to all requirements to cover distances, in particular due to stages involved in the fuel supply chains. Therefore, it is clear that greater environmental benefits could be achieved by reducing supply transport distances or using more sustainable engines. Full article

(This article belongs to the Special Issue Renewable Energy Technologies for Small Scale Applications)

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9628 KiB

Open AccessArticle

Experimental Optimization of Passive Cooling of a Heat Source Array Flush-Mounted on a Vertical Plate

by Antoine Baudoin, Didier Saury, Bo Zhu and Cecilia Boström

Energies 2016, 9(11), 912; https://doi.org/10.3390/en9110912 - 04 Nov 2016

Cited by 4 | Viewed by 4769

Abstract

Heat sources, such as power electronics for offshore power, could be cooled passively—mainly by conduction and natural convection. The obvious advantage of this strategy is its high reliability. However, it must be implemented in an efficient manner (i.e., the area needs to be kept low to limit the construction costs). In this study, the placement of multiple heat sources mounted on a vertical plate was studied experimentally for optimization purposes. We chose a regular distribution, as this is likely to be the preferred choice in the construction process. We found that optimal spacing can be determined for a targeted source density by tuning the vertical and horizontal spacing between the heat sources. The optimal aspect ratio was estimated to be around two. Full article

(This article belongs to the Special Issue Renewable Energy Technologies for Small Scale Applications)

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4763 KiB

Open AccessArticle

Thermochemical Characterizations of Novel Vermiculite-LiCl Composite Sorbents for Low-Temperature Heat Storage

by Yannan Zhang, Ruzhu Wang, Tingxian Li and Yanjie Zhao

Energies 2016, 9(10), 854; https://doi.org/10.3390/en9100854 - 22 Oct 2016

Cited by 41 | Viewed by 6785

Abstract

To store low-temperature heat below 100 °C, novel composite sorbents were developed by impregnating LiCl into expanded vermiculite (EVM) in this study. Five kinds of composite sorbents were prepared using different salt concentrations, and the optimal sorbent for application was selected by comparing both the sorption characteristics and energy storage density. Textural properties of composite sorbents were obtained by extreme-resolution field emission scanning electron microscopy (ER-SEM) and an automatic mercury porosimeter. After excluding two composite sorbents which would possibly exhibit solution leakage in practical thermal energy storage (TES) system, thermochemical characterizations were implemented through simulative sorption experiments at 30 °C and 60% RH. Analyses of thermogravimetric analysis/differential scanning calorimetry (TGA/DSC) curves indicate that water uptake of EVM/LiCl composite sorbents is divided into three parts: physical adsorption of EVM, chemical adsorption of LiCl crystal, and liquid–gas absorption of LiCl solution. Energy storage potential was evaluated by theoretical calculation based on TGA/DSC curves. Overall, EVMLiCl20 was selected as the optimal composite sorbent with water uptake of 1.41 g/g, mass energy storage density of 1.21 kWh/kg, and volume energy storage density of 171.61 kWh/m³. Full article

(This article belongs to the Special Issue Renewable Energy Technologies for Small Scale Applications)

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3599 KiB

Open AccessArticle

Investigation of Energy and Environmental Potentials of a Renewable Trigeneration System in a Residential Application

by Eun-Chul Kang, Euy-Joon Lee, Mohamed Ghorab, Libing Yang, Evgueniy Entchev, Kwang-Seob Lee and Nam-Jin Lyu

Energies 2016, 9(9), 760; https://doi.org/10.3390/en9090760 - 20 Sep 2016

Cited by 14 | Viewed by 5430

Abstract

Micro polygeneration utilizing renewable energy is a suitable approach to reduce energy consumption and carbon emission by offering high-efficiency performance, offsetting the need for centrally-generated grid electricity and avoiding transmission/distribution losses associated with it. This paper investigates the energy and environmental potential of a renewable trigeneration system in a residential application under Incheon (Korea) and Ottawa (Canada) weather conditions. The trigeneration system consists of a ground-to-air heat exchanger (GAHX), photovoltaic thermal (PVT) panels and an air-to-water heat pump (AWHP). The study is performed by simulations in TRNSYS (Version 17.02) environment. The performance of the trigeneration system is compared to a reference conventional system that utilizes a boiler for space and domestic hot water heating and a chiller for space cooling. Simulation results showed substantial annual primary energy savings from the renewable trigeneration system in comparison to the reference system—45% for Incheon and 42% for Ottawa. The CO_2eq emission reduction from the renewable trigeneration system is also significant, standing at 43% for Incheon and 82% for Ottawa. Furthermore, trigeneration systems’ capability to generate electricity and thermal energy at the point of use is considered as an attractive option for inclusion in the future smart energy network applications. Full article

(This article belongs to the Special Issue Renewable Energy Technologies for Small Scale Applications)

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3524 KiB

Open AccessArticle

A Study on Applicability of Distributed Energy Generation, Storage and Consumption within Small Scale Facilities

by Jesús Rodríguez-Molina, José-Fernán Martínez and Pedro Castillejo

Energies 2016, 9(9), 745; https://doi.org/10.3390/en9090745 - 13 Sep 2016

Cited by 12 | Viewed by 5287

Abstract

Distributed generation and storage of energy, conceived as one of the prominent applications of the Smart Grid, has become one of the most popular ways for generation and usage of electricity. Not only does it offer environmental advantages and a more decentralized way to produce energy, but it also enables former consumers to become producers (thus turning them into prosumers). Alternatively, regular power production and consumption is still widely used in most of the world. Unfortunately, accurate business models representations and descriptive use cases for small scale facilitates, either involved in distributed energy or not, have not been provided in a descriptive enough manner. What is more, the possibilities that electricity trade and its storage and consumption activities offer for small users to obtain profits are yet to be addressed and offered to the research community in a thorough manner, so that small consumers will use them to their advantage. This paper puts forward a study on four different business models for small scale facilities and offers an economical study on how they can be deployed as a way to offer profitability for end users and new companies, while at the same time showing the required technological background to have them implemented. Full article

(This article belongs to the Special Issue Renewable Energy Technologies for Small Scale Applications)

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7326 KiB

Open AccessEditor’s ChoiceArticle

Performance Assessment of a Solar-Assisted Desiccant-Based Air Handling Unit Considering Different Scenarios

by Giovanni Angrisani, Carlo Roselli, Maurizio Sasso, Francesco Tariello and Giuseppe Peter Vanoli

Energies 2016, 9(9), 724; https://doi.org/10.3390/en9090724 - 08 Sep 2016

Cited by 13 | Viewed by 7243

Abstract

In this paper, three alternative layouts (scenarios) of an innovative solar-assisted hybrid desiccant-based air handling unit (AHU) are investigated through dynamic simulations. Performance is evaluated with respect to a reference system and compared to those of the innovative plant without modifications. For each scenario, different collector types, surfaces and tilt angles are considered. The effect of the solar thermal energy surplus exploitation for other low-temperature uses is also investigated. The first alternative scenario consists of the recovery of the heat rejected by the condenser of the chiller to pre-heat the regeneration air. The second scenario considers the pre-heating of regeneration air with the warmer regeneration air exiting the desiccant wheel (DW). The last scenario provides pre-cooling of the process air before entering the DW. Results reveal that the plants with evacuated solar collectors (SC) can ensure primary energy savings (15%–24%) and avoid equivalent CO₂ emissions (14%–22%), about 10 percentage points more than those with flat-plate collectors, when the solar thermal energy is used only for air conditioning and the collectors have the best tilt angle. If all of the solar thermal energy is considered, the best results with evacuated tube collectors are approximately 73% in terms of primary energy saving, 71% in terms of avoided equivalent CO₂ emissions and a payback period of six years. Full article

(This article belongs to the Special Issue Renewable Energy Technologies for Small Scale Applications)

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5844 KiB

Open AccessArticle

Analysis of Photovoltaic Self-Consumption Systems

by Carlos J. Sarasa-Maestro, Rodolfo Dufo-López and José L. Bernal-Agustín

Energies 2016, 9(9), 681; https://doi.org/10.3390/en9090681 - 25 Aug 2016

Cited by 19 | Viewed by 5490

Abstract

Components and installation prices could make the self-consumption of solar photovoltaic (PV) systems competitive. In this paper, we explore different self-consumption options, off-grid PV systems (with back-up generator and/or batteries), and grid-connected PV systems under net-metering policies. The calculation of the net present cost (NPC) reveals that the grid-connected PV-only case (for the net-metering scheme) is the most attractive from the technical and financial points of view, with a levelised cost of energy less than 0.1 €/kWh. Off-grid PV + Diesel + Batteries has a higher cost, around two or three times the grid-connected PV-only under net metering. Additionally, the off-grid PV + Diesel is less attractive from a financial point of view, which has a cost of around 10 times the PV-only under net metering. In addition, the values of life cycle CO₂ emissions in each of the cases studied have been compared, and we have concluded that although the off-grid PV + Diesel + Batteries system presents lower CO₂ emissions than the PV-only system, the existence of batteries does not allow one to affirm that the PV + Diesel + Batteries system is the best from an environmental point of view. Full article

(This article belongs to the Special Issue Renewable Energy Technologies for Small Scale Applications)

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4707 KiB

Open AccessArticle

Design, Simulation and Experimental Investigation of a Solar System Based on PV Panels and PVT Collectors

by Annamaria Buonomano, Francesco Calise and Maria Vicidomini

Energies 2016, 9(7), 497; https://doi.org/10.3390/en9070497 - 29 Jun 2016

Cited by 62 | Viewed by 7279

Abstract

This paper presents numerical and experimental analyses aimed at evaluating the technical and economic feasibility of photovoltaic/thermal (PVT) collectors. An experimental setup was purposely designed and constructed in order to compare the electrical performance of a PVT solar field with the one achieved by an identical solar field consisting of conventional photovoltaic (PV) panels. The experimental analysis also aims at evaluating the potential advantages of PVT vs. PV in terms of enhancement of electrical efficiency and thermal energy production. The installed experimental set-up includes four flat polycrystalline silicon PV panels and four flat unglazed polycrystalline silicon PVT collectors. The total electrical power and area of the solar field are 2 kWe and 13 m², respectively. The experimental set-up is currently installed at the company AV Project Ltd., located in Avellino (Italy). This study also analyzes the system from a numerical point of view, including a thermo-economic dynamic simulation model for the design and the assessment of energy performance and economic profitability of the solar systems consisting of glazed PVT and PV collectors. The experimental setup was modelled and partly simulated in TRNSYS environment. The simulation model was useful to analyze efficiencies and temperatures reached by such solar technologies, by taking into account the reference technology of PVTs (consisting of glazed collectors) as well as to compare the numerical data obtained by dynamic simulations with the gathered experimental results for the PV technology. The numerical analysis shows that the PVT global efficiency is about 26%. Conversely, from the experimental point of view, the average thermal efficiency of PVT collectors is around 13% and the electrical efficiencies of both technologies are almost coincident and equal to 15%. Full article

(This article belongs to the Special Issue Renewable Energy Technologies for Small Scale Applications)

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221 KiB

Open AccessArticle

The Regulatory Noose: Logan City’s Adventures in Micro-Hydropower

by Megan Hansen, Randy T. Simmons and Ryan M. Yonk

Energies 2016, 9(7), 482; https://doi.org/10.3390/en9070482 - 23 Jun 2016

Cited by 4 | Viewed by 5294

Abstract

Recent growth in the renewable energy industry has increased government support for alternative energy. In the United States, hydropower is the largest source of renewable energy and also one of the most efficient. Currently, there are 30,000 megawatts of potential energy capacity through small- and micro-hydro projects throughout the United States. Increased development of micro-hydro could double America’s hydropower energy generation, but micro-hydro is not being developed at the same rate as other renewable sources. Micro-hydro is regulated by the Federal Energy Regulatory Commission and subject to the same regulation as large hydroelectric projects despite its minimal environmental impact. We studied two cases of micro-hydro projects in Logan, Utah, and Afton, Wyoming, which are both small rural communities. Both cases showed that the web of federal regulation is likely discouraging the development of micro-hydro in the United States by increasing the costs in time and funds for developers. Federal environmental regulation like the National Environmental Policy Act, the Endangered Species Act, and others are likely discouraging the development of clean renewable energy through micro-hydro technology. Full article

(This article belongs to the Special Issue Renewable Energy Technologies for Small Scale Applications)

4211 KiB

Open AccessEditor’s ChoiceArticle

Prospects of Biodiesel Production from Macadamia Oil as an Alternative Fuel for Diesel Engines

by Md Mofijur Rahman, Mohammad Rasul, Nur Md Sayeed Hassan and Justin Hyde

Energies 2016, 9(6), 403; https://doi.org/10.3390/en9060403 - 25 May 2016

Cited by 35 | Viewed by 9379

Abstract

This paper investigated the prospects of biodiesel production from macadamia oil as an alternative fuel for diesel engine. The biodiesel was produced using conventional transesterification process using the base catalyst (KOH). A multi-cylinder diesel engine was used to evaluate the performance and emission of 5% (B5) and 20% (B20) macadamia biodiesel fuel at different engine speeds and full load condition. It was found that the characteristics of biodiesel are within the limit of specified standards American Society for Testing and Materials (ASTM D6751) and comparable to diesel fuel. This study also found that the blending of macadamia biodiesel–diesel fuel significantly improves the fuel properties including viscosity, density (D), heating value and oxidation stability (OS). Engine performance results indicated that macadamia biodiesel fuel sample reduces brake power (BP) and increases brake-specific fuel consumption (BSFC) while emission results indicated that it reduces the average carbon monoxide (CO), hydrocarbons (HC) and particulate matter (PM) emissions except nitrogen oxides (NO_x) than diesel fuel. Finally, it can be concluded that macadamia oil can be a possible source for biodiesel production and up to 20% macadamia biodiesel can be used as a fuel in diesel engines without modifications. Full article

(This article belongs to the Special Issue Renewable Energy Technologies for Small Scale Applications)

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