Strategies For Energy Efficiency Improvement Research Articles

Study on Energy Efficiency Improvement Strategies of Photovoltaic-Hybrid Energy Storage DC Microgrids under the Concept of Green Energy Conservation

Abstract To improve the energy efficiency of a PV-hybrid energy storage DC microgrid, a series of management strategies are proposed in this paper. According to the working principle of photovoltaic cells, the variable step conductance increment method is used to track and control the output power of photovoltaic cells, and the time constant of the low-pass filter is dynamically adjusted according to the output characteristics of supercapacitors in different SOC intervals, so as to put forward a limit management strategy based on the supercapacitor’s SOC partitioning. An energy management strategy for PV DC microgrid based on hybrid energy storage is proposed to address the impact of internal power fluctuation on DC microgrid operation stability. Based on the voltage deviation range, the system is divided into five operation modes to achieve efficient distribution of system power. Through simulation verification, the charging state difference of the battery bank is reduced by 0.00537 after a charging process of 20 s under the withdrawal and addition of PV power, and the charging power ratio is 5.00:8.14:6.82 at steady state under the withdrawal and addition of the hybrid energy storage unit, U dc = 405.4V. This paper’s strategy makes the DC microgrid effective in improving energy efficiency and smoothing out power fluctuations in all operating modes.

Energy Performance Certificate renewal — An analysis of reliability of simple non-domestic buildings ’ EPC ratings and pragmatic improving strategies in the UK

Energy Performance Certificates (EPCs) are designed to provide consistent and comparable energy efficiency ratings. Since 2008, any building constructed, rented or sold is required to obtain an EPC in the UK. 4% of simple office buildings have renewed their EPC to date in England and Wales. In this paper, by comparing the original and renewed EPCs of these buildings, we examine the reliability of non-domestic EPC ratings and discover realistic energy efficiency improvement strategies reflected in the changes. We have found that buildings with their conditions remaining unchanged can be better rated by approximately 10 points on average when their initial rating is above the minimum requirement in the regulation. The ones initially rated below the minimum requirement are expected to have a greater scale of improvement on ratings while making no efforts which brings doubts on the effect of the “Minimum Energy Efficiency Standard” policy. Evidenced human factors are also jeopardising the fairness of EPC ratings. Based on the changes in the EPCs, we have found 4 clusters of improved buildings and 5 clusters of deteriorated buildings. We derived practical energy efficiency improvement strategies that people have already naturally adopted.

Energy Efficiency Improvement Assessment in Africa: An Integrated Dynamic DEA Approach

In Africa, energy plays an important role in the processes of economic and sustainable development. However, inefficiency such as mismanagement of resources constrains productivity. Prior energy efficiency studies in Africa have failed to provide the paths through which energy efficiency improvement can be achieved. The current study aims to assess energy efficiency improvement among 25 selected countries in Africa. First, the dynamic slack-based measure (DSBM) data envelopment analysis (DEA) model is applied to gauge the efficiency measurement. Further, the Malmquist productivity index (MPI) is employed to investigate the energy efficiency improvement during 2006–2014. Empirically, the results from the dynamic slack-based measure (DSBM) model show that energy efficiency in Africa is generally low. Also, the findings from the MPI suggest there is no significant improvement in energy efficiency in Africa. Based on the estimated results, some energy efficiency improvement strategies are further proposed for sample countries in Africa.

Petri net-based scheduling strategy and energy modeling for the cylinder block remanufacturing under uncertainty

Scheduling has been extensively applied to remanufacturing for the organization of production activities, and it would directly influence the overall performance of the remanufacturing system. Since the conjunction of Petri net (PN) and artificial intelligence (AI) searching technique was demonstrated to be a promising approach to solve the scheduling problems in manufacturing systems, this study built a transition timed PN combined with heuristic A* algorithm to deal with the scheduling in remanufacturing. The PN was applied to the formulation of remanufacturing process, while the A* algorithm generated and searched for an optimal or near optimal feasible schedule through the reachability graph (RG). We took the high value-added cylinder block of engine as a research object to minimize the makespan of reprocessing a batch used components. This scheduling problem involved in batch and parallel processing machines, and the uncertain processing time and routes will complicate the scheduling problem. Three heuristics were designed to guide the search process through the RG in PN. To avoid state space explosion and select promising nodes, a new rule-based dynamic window was developed to improve the efficiency of the algorithm, and this rule was examined to outperform the conventional one. Under the determined scheduling strategy, the dynamic behavior of energy consumption rate during the processing time was simulated using PN tool, which would assist remanufacturers to develop potential strategies for energy efficiency improvement. Considering the uncertainty of processing time, the Monte Carlo simulation method was adopted to statistically analyze the distributions of makespan and total energy consumption, which would contribute to the comprehensive production scheduling and energy profile assessment for sustainable remanufacturing.

Energy Efficiency Improvement Strategies for Boilers: A Case Study in Pharmacy Industry

Energy resources are gradually scarce and expensive. Raised a gap between increasing demand and energy supply. Bridging gap of demand together with energy supply by increase energy supplies is a very costly decision. Moreover, in the industrial sector with the high cost of energy, the longer the competitiveness decreases. Energy costs in total production costs reduce the number of profits each year. The strategy to prevent these problems is by increasing the efficiency of industrial operations and equipment. Several stages of the efficiency process begin with identifying balance, energy-saving opportunities, and energy utilization. This stage is better known as an energy audit. The advanced stage of the energy audit helps identify potential energy conservation and encourages the industry to focus on efficiency and conservation and is supported by adequate financing. In the research strategy, the opportunity to save energy costs in oil boiler units is practical, sustainable and economically feasible. On the results of measurements and calculations obtained boiler efficiency of 53.67% where the factors that cause the low efficiency of this boiler are the high excess water by 17.32% and heat loss from dry exhaust gas by 42.03%. The solution is done by controlling excess air by regulating the air entering the combustion chamber. In this way, energy savings can be increased by 15%.

A review of energy efficient methods for all-electric ships

With stringent environmental regulations and growing concerns on energy consumption of the marine transport sector, there is a serious effort to make on board energy system more efficient. Improving fuel efficiency is conceived as a sustainable measure in terms of reducing greenhouse gas (GHG) emissions and overall marine energy use. As such, electrification of ship propulsion has been introduced as a solution for operating at higher efficiency and hence more saving fuel. However, energy efficiency in the context of marine transport is to be more stringent over time as required by International Maritime Organization (IMO). The energy performance indicators to evaluate such requirements include Energy Efficiency Design Index (EEDI) and Energy Efficiency Operational Indicator (EEOI). Several energy efficient methods are therefore proposed to further improve fuel efficiency on board electric vessels. These involve integration of energy storage system, implementation of DC distribution, optimal power distribution and scheduling as well as various operational practices that are currently applicable for existing conventional vessels. The paper summaries the concept of ship energy efficiency in terms of the standard indicators and provide a brief review on the energy efficiency improvement strategies published in literature. The aim of the review is to analyze the methods that are potential to incorporate into the autonomous system of all-electric vessels. The results show a significant variation in reported efficiency gain and thus a combination of various methods is suggested to achieve full potential for emissions reduction.

On the application of wireless sensors and actuators network in existing buildings for occupancy detection and occupancy-driven lighting control

Buildings have in recent years been the target of a number of energy efficiency improvement strategies given that they are a major energy end-use sector in most countries. Whilst new buildings due to legislations, increasingly address sustainability and improved energy efficiency considerations, the refurbishment process of older buildings still presents a number of challenges. Advancement in Information and Communication Technology, particularly the application of low-cost Wireless Sensors and Actuators Network does however provide the opportunity to harness yet unrealized energy reduction in existing buildings. This paper presents results from an experimental study evaluating the performance and energy saving potentials of such off-the-shelve, low-cost wireless sensors and actuators network in an existing office building for occupancy detection and occupancy-driven lighting control. The study demonstrates that in addition to improved occupancy information obtainable from Wireless Sensors and Actuators Network, worthwhile savings in the energy consumption of the lighting systems can as well be achieved.

Strategies for Energy Efficiency Improvement in Zimbabwean Industries Using the Energy Audit

Energy efficiency is a modern approach for using energy resources economically. Energy audit ensures that every unit of energy gives the maximum in terms of production. This paper brings out the advantages of using energy audit to save future installation of power generation capacity and load reduction of distribution systems. It also envisages the introduction of energy conservation techniques to eliminate sub-standard equipment.

Renewable Energy Systems: Industrial and Home Best Practise Case Studies

The use of renewable energies and energy efficiency improvement systems is sometimes constrained by the investment needed for devices and its installation. However, governments have developed policies to reduce the initial costs to end-users. The increasing number of renewable energy systems can help in the reduction of the global dependency on fossil energy sources, and simultaneously can help to ensure that the carbon dioxide emissions quota is not exceeded, aiming a reduction of the green-house effect. In this sense, this paper presents two best practise case studies. One of them is in the industrial context and other in the residence context, concerning the use of renewable energy systems and energy efficiency improvement strategies. The best practice case study in industrial context involves the renewable energy systems design in an automotive sector factory, making use of solar thermal panels and energy efficiency measures. The non-industrial case study covers the analysis of the energy efficiency improvement using a thermal energy recovery system from hot water used in daily baths or showers. The direct benefits (savings) and indirect (impacts) are analysed for both case studies.

Energy efficiency improvement strategies for a diesel engine in low-temperature combustion

The lowered combustion temperature in diesel engines is capable of reducing nitrogen oxides and soot simultaneously, which can be implemented by the heavy use of exhaust gas recirculation (EGR) or the homogeneous charge compression ignition (HCCI) type of combustion. However, the fuel efficiency of the low-temperature combustion (LTC) cycles is commonly compromised by the high levels of hydrocarbon and carbon monoxide emissions. More seriously, the scheduling of fuel delivery in HCCI engines has lesser leverage on the exact timing of auto-ignition that may even occur before the compression stroke is completed, which may cause excessive efficiency reduction and combustion roughness. New LTC control strategies have been explored experimentally to achieve ultralow emissions under independently controlled EGR, intake boost, exhaust backpressure, and multi-event fuel-injection events. Empirical comparisons have been made between the fuel efficiencies of LTC and conventional diesel cycles. Preliminary adaptive control strategies based on cylinder pressure characteristics have been implemented to enable and stabilize the LTC when heavy EGR is applied. The impact of heat-release phasing, duration, shaping, and splitting on the thermal efficiency has also been analyzed with engine cycle simulations. This research intends to identify the major parameters that affect diesel LTC engine thermal efficiency. Copyright © 2008 John Wiley & Sons, Ltd.