Energy Saving

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 (31 May 2017) | Viewed by 42495

Special Issue Editor


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Guest Editor
Power Electronics Research Centre, Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong, China
Interests: electric vehicle; electromagnetics; motor drives; renewable energy and energy systems
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Special Issue Information

Dear Colleagues,

Nowadays, saving energy is everyone’s top priority. This is not only due to global warming, but, also, public awareness regarding energy and pollution is the major issue of this century. Extensive research has been conducted over the last 40 years. Industrial products, in terms of energy saving apparatus, software, internal sub-circuits, and operation modes, have been developed in order to enhance energy saving. Conventional methods of saving energy include the use of new and higher performance of devices, new products, and improved control methods or algorithms. Saving energy also covers the proper use of renewable energy in order to assist energy saving, and the use of energy storage devices to store energy for later use. Today, energy saving research also extends to electric mobility, lighting, and air conditioning and ventilation. Extension of product life times and reduction of waste are alternative approaches for saving energy and substantial research has been reported.

The Special Issue of the journal Applied Sciences, “Energy Saving”, aims to cover recent advances in the development of technologies of any type to provide energy saving, reduce loss, improve performance, extend life times, and reduce waste. 

Prof. Eric Ka-Wai Cheng
Guest Editor

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Keywords

  • Battery system and energy storage
  • Electric mobility
  • Lighting and heating
  • Energy saving control
  • Ventilation and air conditioning
  • Renewable energy
  • Life time improvement
  • Waste and second life of retired product technologies

Published Papers (7 papers)

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Research

4335 KiB  
Article
Optimal Control and Operation Strategy for Wind Turbines Contributing to Grid Primary Frequency Regulation
by Mun-Kyeom Kim
Appl. Sci. 2017, 7(9), 927; https://doi.org/10.3390/app7090927 - 08 Sep 2017
Cited by 24 | Viewed by 4989
Abstract
This study introduces a frequency regulation strategy to enable the participation of wind turbines with permanent magnet synchronous generators (PMSGs). The optimal strategy focuses on developing the frequency support capability of PMSGs connected to the power system. Active power control is performed using [...] Read more.
This study introduces a frequency regulation strategy to enable the participation of wind turbines with permanent magnet synchronous generators (PMSGs). The optimal strategy focuses on developing the frequency support capability of PMSGs connected to the power system. Active power control is performed using maximum power point tracking (MPPT) and de-loaded control to supply the required power reserve following a disturbance. A kinetic energy (KE) reserve control is developed to enhance the frequency regulation capability of wind turbines. The coordination with the de-loaded control prevents instability in the PMSG wind system due to excessive KE discharge. A KE optimization method that maximizes the sum of the KE reserves at wind farms is also adopted to determine the de-loaded power reference for each PMSG wind turbine using the particle swarm optimization (PSO) algorithm. To validate the effectiveness of the proposed optimal control and operation strategy, three different case studies are conducted using the PSCAD/EMTDC simulation tool. The results demonstrate that the optimal strategy enhances the frequency support contribution from PMSG wind turbines. Full article
(This article belongs to the Special Issue Energy Saving)
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4729 KiB  
Article
Ideal Operation of a Photovoltaic Power Plant Equipped with an Energy Storage System on Electricity Market
by Markku Järvelä and Seppo Valkealahti
Appl. Sci. 2017, 7(7), 749; https://doi.org/10.3390/app7070749 - 23 Jul 2017
Cited by 9 | Viewed by 4556
Abstract
There is no natural inertia in a photovoltaic (PV) generator and changes in irradiation can be seen immediately at the output power. Moving cloud shadows are the dominant reason for fast PV power fluctuations taking place typically within a minute between 20 to [...] Read more.
There is no natural inertia in a photovoltaic (PV) generator and changes in irradiation can be seen immediately at the output power. Moving cloud shadows are the dominant reason for fast PV power fluctuations taking place typically within a minute between 20 to 100% of the clear sky value roughly 100 times a day, on average. Therefore, operating a utility scale grid connected PV power plant is challenging. Currently, in many regions, renewable energy sources such as solar and wind receive feed-in tariffs that ensure a certain price for the energy. On the other hand, electricity markets operate on a supply-demand principle and a typical imbalance settlement period is one hour. This paper presents the energy, power and corresponding requirements for an energy storage system in a solar PV power plant to feed the power to the grid meeting the electricity spot markets practices. An ideal PV energy production forecast is assumed to be available to define reference powers of the system for the studied imbalance settlement periods. The analysis is done for three different PV system sizes using the existing irradiance measurements of the Tampere University of Technology solar PV power station research plant. Full article
(This article belongs to the Special Issue Energy Saving)
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1894 KiB  
Article
Decision Optimization for Power Grid Operating Conditions with High- and Low-Voltage Parallel Loops
by Dong Yang, Kang Zhao, Hao Tian and Yutian Liu
Appl. Sci. 2017, 7(5), 487; https://doi.org/10.3390/app7050487 - 09 May 2017
Cited by 3 | Viewed by 4920
Abstract
With the development of higher-voltage power grids, the high- and low-voltage parallel loops are emerging, which lead to energy losses and even threaten the security and stability of power systems. The multi-infeed high-voltage direct current (HVDC) configurations widely appearing in AC/DC interconnected power [...] Read more.
With the development of higher-voltage power grids, the high- and low-voltage parallel loops are emerging, which lead to energy losses and even threaten the security and stability of power systems. The multi-infeed high-voltage direct current (HVDC) configurations widely appearing in AC/DC interconnected power systems make this situation even worse. Aimed at energy saving and system security, a decision optimization method for power grid operating conditions with high- and low-voltage parallel loops is proposed in this paper. Firstly, considering hub substation distribution and power grid structure, parallel loop opening schemes are generated with GN (Girvan-Newman) algorithms. Then, candidate opening schemes are preliminarily selected from all these generated schemes based on a filtering index. Finally, with the influence on power system security, stability and operation economy in consideration, an evaluation model for candidate opening schemes is founded based on analytic hierarchy process (AHP). And a fuzzy evaluation algorithm is used to find the optimal scheme. Simulation results of a New England 39-bus system and an actual power system validate the effectiveness and superiority of this proposed method. Full article
(This article belongs to the Special Issue Energy Saving)
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4195 KiB  
Article
An Improvement of a Fuzzy Logic-Controlled Maximum Power Point Tracking Algorithm for Photovoltic Applications
by Woonki Na, Pengyuan Chen and Jonghoon Kim
Appl. Sci. 2017, 7(4), 326; https://doi.org/10.3390/app7040326 - 29 Mar 2017
Cited by 31 | Viewed by 5953
Abstract
This paper presents an improved maximum power point tracking (MPPT) algorithm using a fuzzy logic controller (FLC) in order to extract potential maximum power from photovoltaic cells. The objectives of the proposed algorithm are to improve the tracking speed, and to simultaneously solve [...] Read more.
This paper presents an improved maximum power point tracking (MPPT) algorithm using a fuzzy logic controller (FLC) in order to extract potential maximum power from photovoltaic cells. The objectives of the proposed algorithm are to improve the tracking speed, and to simultaneously solve the inherent drawbacks such as slow tracking in the conventional perturb and observe (P and O) algorithm. The performances of the conventional P and O algorithm and the proposed algorithm are compared by using MATLAB/Simulink in terms of the tracking speed and steady-state oscillations. Additionally, both algorithms were experimentally validated through a digital signal processor (DSP)-based controlled-boost DC-DC converter. The experimental results show that the proposed algorithm performs with a shorter tracking time, smaller output power oscillation, and higher efficiency, compared with the conventional P and O algorithm. Full article
(This article belongs to the Special Issue Energy Saving)
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8382 KiB  
Article
Application of a High-Power Reversible Converter in a Hybrid Traction Power Supply System
by Gang Zhang, Jianglin Qian and Xinyu Zhang
Appl. Sci. 2017, 7(3), 282; https://doi.org/10.3390/app7030282 - 14 Mar 2017
Cited by 15 | Viewed by 7881
Abstract
A high-power reversible converter can achieve a variety of functions, such as recovering regenerative braking energy, expanding traction power capacity, and improving an alternating current (AC) grid power factor. A new hybrid traction power supply scheme, which consists of a high-power reversible converter [...] Read more.
A high-power reversible converter can achieve a variety of functions, such as recovering regenerative braking energy, expanding traction power capacity, and improving an alternating current (AC) grid power factor. A new hybrid traction power supply scheme, which consists of a high-power reversible converter and two 12-pulse diode rectifiers, is proposed. A droop control method based on load current feed-forward is adopted to realize the load distribution between the reversible converter and the existing 12-pulse diode rectifiers. The direct current (DC) short-circuit characteristics of the reversible converter is studied, then the relationship between the peak fault current and the circuit parameters is obtained from theoretical calculations and validated by computer simulation. The first two sets of 2 MW reversible converters have been successfully applied in Beijing Metro Line 10, the proposed hybrid application scheme and coordinated control strategy are verified, and 11.15% of average energy-savings is reached. Full article
(This article belongs to the Special Issue Energy Saving)
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2168 KiB  
Article
LED Current Balance Using a Variable Voltage Regulator with Low Dropout vDS Control
by Hung-I Hsieh and Hao Wang
Appl. Sci. 2017, 7(2), 206; https://doi.org/10.3390/app7020206 - 20 Feb 2017
Cited by 5 | Viewed by 6186
Abstract
A cost-effective light-emitting diode (LED) current balance strategy using a variable voltage regulator (VVR) with low dropout vDS control is proposed. This can regulate the multiple metal-oxide-semiconductor field-effect transistors (MOSFETs) of the linear current regulators (LCR), maintaining low dropout vDS on the flat [...] Read more.
A cost-effective light-emitting diode (LED) current balance strategy using a variable voltage regulator (VVR) with low dropout vDS control is proposed. This can regulate the multiple metal-oxide-semiconductor field-effect transistors (MOSFETs) of the linear current regulators (LCR), maintaining low dropout vDS on the flat vGS-characteristic curves and making all drain currents almost the same. Simple group LCRs respectively loaded with a string LED are employed to implement the theme. The voltage VVdc from a VVR is synthesized by a string LED voltage NvD, source voltage vR, and a specified low dropout vDS = VQ. The VVdc updates instantly, through the control loop of the master LCR, which means that all slave MOSFETs have almost the same biases on their flat vGS-characteristic curves. This leads to all of the string LED currents being equal to each other, producing an almost even luminance. An experimental setup with microchip control is built to verify the estimations. Experimental results show that the luminance of all of the string LEDs are almost equal to one another, with a maximum deviation below 1% during a wide dimming range, while keeping all vDS of the MOSFETs at a low dropout voltage, as expected. Full article
(This article belongs to the Special Issue Energy Saving)
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4913 KiB  
Article
A Single-Stage LED Tube Lamp Driver with Power-Factor Corrections and Soft Switching for Energy-Saving Indoor Lighting Applications
by Chun-An Cheng, En-Chih Chang, Ching-Hsien Tseng and Tsung-Yuan Chung
Appl. Sci. 2017, 7(2), 115; https://doi.org/10.3390/app7020115 - 24 Jan 2017
Cited by 13 | Viewed by 7296
Abstract
This paper presents a single-stage alternating current (AC)/direct current (DC) light-emitting diode (LED) tube lamp driver for energy-saving indoor lighting applications; this driver features power-factor corrections and soft switching, and also integrates a dual buck-boost converter with coupled inductors and a half-bridge series [...] Read more.
This paper presents a single-stage alternating current (AC)/direct current (DC) light-emitting diode (LED) tube lamp driver for energy-saving indoor lighting applications; this driver features power-factor corrections and soft switching, and also integrates a dual buck-boost converter with coupled inductors and a half-bridge series resonant converter cascaded with a bridge rectifier into a single-stage power-conversion topology. The features of the presented driver are high efficiency (>91%), satisfying power factor (PF > 0.96), low input-current total-harmonic distortion (THD < 10%), low output voltage ripple factor (<7.5%), low output current ripple factor (<8%), and zero-voltage switching (ZVS) obtained on both power switches. Operational principles are described in detail, and experimental results obtained from an 18 W-rated LED tube lamp for T8/T10 fluorescent lamp replacements with input utility-line voltages ranging from 100 V to 120 V have demonstrated the functionality of the presented driver suitable for indoor lighting applications. Full article
(This article belongs to the Special Issue Energy Saving)
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