scholarly journals Modelling energy efficiency and generation potential in the South African wastewater services sector

2020 ◽  
Vol 81 (5) ◽  
pp. 876-890
Author(s):  
John N. Zvimba ◽  
Eustina V. Musvoto
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
South African ◽  
Energy Savings ◽  
Water Cycle ◽  
Cost Savings ◽  
Optimal Process ◽  
The South ◽  
Services Sector ◽  
Energy Conservation Measures

Abstract About 55% of energy used in the South African water cycle is for wastewater treatment, with the bulk of this energy associated with aeration in biological processes. However, up to 15% of wastewater energy demand can be offset by energy generation from sludge (power and/or combined heat and power), while best practices adoption can deliver energy efficiency gains of between 5% and 25% in the water cycle. Advanced process modelling and simulation has been applied in this study as a tool to evaluate optimal process and aeration control strategies. This study further applied advanced modelling to investigate and predict the potential energy consumption and consumption cost pattern by the South African wastewater sector resulting from implementation of optimal process and aeration energy use reduction strategies in support of sustainable municipal wastewater management. Aeration energy consumption and cost savings of 9–45% were demonstrated to be achievable through implementation of energy conservation measures without compromising final effluent regulatory compliance. The study further provided significant potential future energy savings as high as 50% and 78% through implementation of simple and complex aeration energy conservation measures respectively. Generally, the model-predicted energy savings suggest that adoption of energy efficiency should be coupled with electricity generation from sludge in order to achieve maximum energy consumption and cost savings within the South African wastewater services sector.

Reducing Energy Costs With Electric, Diesel and Dual-Powered Locomotives

2009 ◽  
Author(s):  
Janis Vitins
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Energy Savings ◽  
New Technologies ◽  
Cost Savings ◽  
Energy Costs ◽  
Aggressive Driving ◽  
Driving Style ◽  
Mixed Network ◽  
Reduce Energy Consumption

Typically, the costs for traction energy add up to 20% or more of the total train operating costs with electric locomotives in Europe. Therefore, there is a high incentive for the railroads to reduce energy consumption and thus to improve operating margins. Additionally, rising costs for energy as well as environmental aspects will increase the need to reduce energy consumption in the future. Firstly, on electric locomotives the largest energy savings are obtained from power regeneration at braking. In this mode the locomotive acts as a moving power generator feeding energy back into the catenary network. Savings are typically in the range of 10 to 30%. Secondly, the driving style has a high impact on energy costs. Energy consumption can be lowered by more than 20% through an energy conscious driving style compared to aggressive driving. Thirdly, the energy efficiency of the whole traction chain is important. Electric locomotives designed for AC catenaries have an overall energy efficiency of up to 86%. Locomotives designed for 1.5 or 3 kV DC catenaries can have an overall energy efficiency of up to 90%. New technologies can potentially help to increase the power efficiencies even further. Apart from using efficient diesel engines, the fuel costs of diesel-electric locomotives can be reduced much in the same way as with electric locomotives. Regeneration of braking power on diesel-electric locomotives is, however, limited to feeding the auxiliaries and head end power (HEP) to passenger coaches. In Europe the energy costs per hauled ton-km are typically much lower with electric than with diesel traction. This gives dual-powered locomotives the advantage of overall lower energy costs for operation on both electrified and non-electrified networks. First estimates show that the total energy costs (diesel and electric operation) can be reduced by more than 35% in a mixed network with 80% electrification with a dual-powered locomotive compared to a diesel locomotive running the same train on the same route. In addition, the dual-powered locomotive provides major cost savings and increased quality of service with a one seat ride.

scholarly journals Improving the economic performances of the beet-sugar industry

2008 ◽  
pp. 55-61 ◽  
Author(s):  
Bojana Prodanic ◽  
Aleksandar Jokic ◽  
Jelena Markovic ◽  
Zoltan Zavargo
Keyword(s):  
European Union ◽  
Energy Efficiency ◽  
Energy Consumption ◽  
Energy Savings ◽  
General Trend ◽  
Sugar Industry ◽  
Regional Level ◽  
Efficiency Improvement ◽  
Considerable Saving ◽  
Energy Efficiency Improvement

General trend of free trade at the regional level as well as in the direction of European Union has motivated sugar factories located in Serbia to invest into technologies that are more efficient in order to make their products more competitive in the markets of Europe. Until 2005, the project of energy efficiency improvement in Serbian sugar factories was conducted in Crvenka and Zabalj. Now, they have energy consumption around 1 MJ/kg beet, in contrast to the previous consumption of 1.2 up to 1.5 MJ/kg beet. Further improvements are possible but investments would be high. A result of measurements taken during 2006, after the sugar factory "Donji Srem" - Pecinci was reconstructed showed that a considerable saving has been achieved. The first set of measurements showed that the energy consumption was 1.01 MJ/kg beet, which was 20% higher than intended, but at the same time energy savings were about 30% lower with respect to the values before the reconstruction.

scholarly journals Optimization of Energy Efficiency, Operation Costs, Carbon Footprint and Ecological Footprint with Reverse Osmosis Membranes in Seawater Desalination Plants

Membranes ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 781
Author(s):  
Federico Leon ◽  
Alejandro Ramos ◽  
S. Ovidio Perez-Baez
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Reverse Osmosis ◽  
Ecological Footprint ◽  
Energy Savings ◽  
Seawater Desalination ◽  
Operation Costs ◽  
Private And Public ◽  
Desalination Plants ◽  
Reverse Osmosis Membranes

This article shows the optimization of the reverse osmosis process in seawater desalination plants, taking the example of the Canary Islands, where there are more than 320 units of different sizes, both private and public. The objective is to improve the energy efficiency of the system in order to save on operation costs as well as reduce the carbon and ecological footprints. Reverse osmosis membranes with higher surface area have lower energy consumption, as well as energy recovery systems to recover the brine pressure and introduce it in the system. Accounting for the operation, maintenance and handling of the membranes is also important in energy savings, in order to improve the energy efficiency. The energy consumption depends on the permeate water quality required and the model of the reverse osmosis membrane installed in the seawater desalination plant, as it is shown in this study.

E|Benchmark - Approaches and Methods for Assessing the Energy Efficiency of the Industrial Automated Product Manufacturing

2014 ◽  
Vol 655 ◽  
pp. 15-20 ◽  
Author(s):  
Sven Kreitlein ◽  
Tobias Rackow ◽  
Jörg Franke
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Energy Savings ◽  
Value Systems ◽  
Course Of Action ◽  
Product Manufacturing ◽  
Actual Energy Consumption ◽  
Related Characteristic ◽  
Industry Comparison ◽  
Successive Calculation

This paper introduces a method for the assessment and evaluation of energy efficiency of the manufacturing processes in the production as well as a corporate and cross-industry comparison. Already today, energy-related characteristic value systems are used, which are related to the energy consumption of large electronic household appliances or are focusing on their production facilities. The energy efficiency value is a newly developed indicator and will provide valuable information about the energy efficiency of the production of various products, production operators, and consumers. In the following, the energy efficiency value, which is based on the approach of minimal value calculation, is presented in detail. The basic idea is the comparison and evaluation of energy efficiency based on the ratio of the theoretically required energy consumption to the actual energy consumption. Depending on the analysis of influencing factors, a model highlighting their dependencies could be established. The developed system hinges on a successive calculation of the minimum value. Each of these minimum types can be put in relation to the measured energy consumption. However, depending on the chosen basis, the conclusion and focus of the calculated key figure may vary. By using the real minimum as a basis, the actually existing energy savings become visible. The method will be put to the test through an exemplary application for processes in the fields of cutting technologies. This course of action allows for the validation of the developed energy efficiency value and reveals the potential of this method.

Influence of Volumetric Capacity on Energy Consumption in Oil-Lubricated Compressed Air Systems

2016 ◽  
Vol 8 (4) ◽  
Author(s):  
Pawel Olszewski ◽  
Claus Borgnakke
Keyword(s):  
Mathematical Model ◽  
Energy Efficiency ◽  
Energy Consumption ◽  
Potential Energy ◽  
Uncertainty Analysis ◽  
Control Strategy ◽  
Energy Savings ◽  
Compressed Air ◽  
Numerical Code ◽  
Volumetric Capacity

The aim of this research is to estimate the influence of compressed air volumetric capacity on the energy consumption in systems equipped with oil-lubricated screw compressors. A mathematical model of oil-lubricated screw compressors has been proposed. The model is verified by comparing with real measurements, and overall uncertainty analysis is estimated. An in-house developed numerical code (c++) is used to calculate the energy consumption in 252,000 combinations. The final result can be used to estimate the energy efficiency of existing air systems and to assess potential energy savings due to changes in the operation of the system and its control strategy.

scholarly journals Lighting Control Including Daylight and Energy Efficiency Improvements Analysis

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2166 ◽  
Author(s):  
Aniela Kaminska ◽  
Andrzej Ożadowicz
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Energy Savings ◽  
Residential Buildings ◽  
Experimental Tests ◽  
Experimental Results ◽  
Automation System ◽  
Building Automation ◽  
Total Energy Consumption ◽  
Lighting Control

Energy used for lighting is one of the major components of total energy consumption in buildings. Nowadays, buildings have a great potential to reduce their energy consumption, but to achieve this purpose additional efforts are indispensable. In this study, the need for energy savings evaluation before the implementation of lighting control algorithms for a specified building is highlighted. Therefore, experimental tests have been carried out in a university building with laboratories and other rooms, equipped with KNX building automation system. A dimmable control strategy has been investigated, dependent on daylight illuminance. Moreover, a relationship between external and internal daylight illuminance levels has been evaluated as well. Based on the experimental results, the authors proposed a method for the rough estimation of electrical energy savings. Since, according to the EN 15232 standard, Building Automation and Control Systems (BACS) play an important role in buildings’ energy efficiency improvements, the BACS efficiency factors from this standard have been used to verify the experimental results presented in the paper. The potential to reduce energy consumption from lighting in non-residential buildings by 28% for offices and 24% for educational buildings has been confirmed, but its dependence on specific building parameters has been discussed as well.

scholarly journals Quantitative Analysis of Consumer Preferences of Windows Set in South Korea: The Role of Energy Efficiency Levels

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1816 ◽  
Author(s):  
Kwan Byum Maeng ◽  
Jiyeon Jung ◽  
Yoonmo Koo
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
South Korea ◽  
Willingness To Pay ◽  
Energy Savings ◽  
Consumer Preferences ◽  
Mixed Logit ◽  
The Government ◽  
The Cost

The building sector is considered to be important for Korean energy issues as it accounts for approximately 20% of Korea’s final energy consumption. As one of Korea’s passive strategies in its emission reduction plan is reducing energy consumption through improvements in energy efficiency because the energy loss mostly occurs from window sets, this study aims to examine the preferences and role of the energy efficiency level of window sets in South Korea. Given that the lifespan of a building exceeds 20 years, a building’s energy efficiency significantly impacts accumulated energy savings. However, window sets affect not only energy efficiency, but also the interior appearance of the building; therefore, it is important to understand consumer preferences and to examine their effect on building energy reduction accordingly. Using a mixed logit model, this study analyzes window set preferences and energy savings. As a result, this study determines that consumers consider the energy efficiency level to be the second most important factor in determining window preference, following the cost of the window. In addition, this study found that the marginal willingness to pay for efficiency level 2 window sets compared to level 3 window sets is USD 1256. For level 1 window sets, this figure increases to USD 3140. Further, a scenario analysis is conducted to analyze the government incentive program’s effectiveness in encouraging consumers to purchasing higher energy efficiency more efficient products, and thus in promoting the eco-friendly consumption of in households. Taking into consideration of households’ willingness to pay and cost saving amount for using energy efficient window sets, the optimal value of government incentives of is found to be approximately USD 700 is found to be optimal.

Energy efficiency in the European water industry: learning from best practices

2012 ◽  
Vol 3 (1) ◽  
pp. 11-17 ◽  
Author(s):  
J. Frijns ◽  
R. Middleton ◽  
C. Uijterlinde ◽  
G. Wheale
Keyword(s):  
Energy Efficiency ◽  
Best Practices ◽  
Energy Efficient ◽  
Energy Savings ◽  
Water Cycle ◽  
Biogas Production ◽  
Energy Generation ◽  
Water Industry ◽  
Efficient Design ◽  
European Water

Energy costs and climate change challenges the water industry to improve their energy efficiency. The number of examples of energy measures in water production and treatment is growing rapidly. In this paper, best practices of energy efficiency from the European water industry are presented with the objective of learning from each other. The best practices are collected within the framework of the Global Water Research Coalition's attempt to devise a global compendium ‘Best practices in the energy efficient design and operation of water industry assets’. The case studies in the compendium show significant energy savings in all parts of the water cycle. Examples with potential include the improved operational set up of pumping design, on line aeration control, and energy-efficient bubble aerators and sludge belt thickeners. Next to optimising energy efficiency across the water cycle, there are also opportunities for energy generation. Promising practices include biogas production from sludge (co)digestion and hydraulic energy generation from micro-turbines.

scholarly journals The Strategy of Implementing Energy Efficiency Standards and Labels for Domestic Air Conditioners in Libya

2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Salah M Alabani ◽  
Ibrahim H Tawil
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Energy Savings ◽  
Residential Buildings ◽  
Total Energy Consumption ◽  
Air Conditioners ◽  
Improve Energy Efficiency ◽  
Reduce Energy Consumption ◽  
Two Stages ◽  
Energy Efficiency Standards

The residential sector in Libya has grown over the past decade in the construction of residential buildings due to the increase in the population. Moreover, the increase in the level of income has contributed to the increase in the purchase of household appliances, which leads to increased demand for energy. Energy consumption in the household sector accounted for 31% of total energy consumption during 2010, and the share of air conditioners in this sector consumed 18.35%. To reduce energy consumption and improve energy efficiency in this sector, policies should be considered to apply energy efficiency standards and markers to household electrical appliances, as they are considered one of the most successful programs used in the world. Countries are implementing such programs to reduce energy consumption in the domestic sector. This paper presents the possibility of implementing such programs to introduce the importance of energy efficiency standards and labeling programs for home appliances in Libya. The calculations required to design such programs show the energy savings that can be achieved during cooling loads in the summer period of 4 months July, August, September). A strategic plan has been developed during 10-year (2020-2030) to estimate the expected savings of energy consumed and to identify possible obstacles and difficulties by gradually increasing the energy efficiency ratio for comestic air conditioners in two stages, from EER10 to EER11 in the first stage is then raised to EER12 as the second stage.

Energy Efficiency in K-12 Schools: A Case Study in Florida

2020 ◽  
Author(s):  
Ganesh Doiphode ◽  
Hamidreza Najafi ◽  
Mariana Migliori Favaretto
Keyword(s):  
Energy Efficiency ◽  
Public Schools ◽  
Energy Consumption ◽  
Energy Savings ◽  
The United States ◽  
Payback Period ◽  
Background Information ◽  
Subtropical Climate ◽  
Institute Of Technology ◽  
K 12

Abstract Buildings are one of the largest energy consumers in the United States. K-12 schools are responsible for nearly 8% of energy consumption by commercial buildings which is equivalent to 1.44% of total annual energy consumption in the country. Understanding the baseline energy consumption of the schools as well as identifying effective energy efficiency measures (EEMs) that result in significant energy savings without compromising occupant’s comfort in a given climate condition are essential factors in moving towards a sustainable future. In a collaboration between Florida Institute of Technology and Brevard Public Schools, three schools are identified for a test study in Melbourne, FL, representing the humid subtropical climate. Energy audit is conducted for these schools and monthly utility bill data as well as background information, end-user’s data and their associated operating schedules are obtained. A detailed analysis is performed on the utility bill data and energy consumption by each end-user is estimated. Several EEMs are considered and evaluated to achieve an improved energy efficiency for the schools. The implementation cost of each EEM and the associated simple payback period is also determined. A study is also conducted to explore possibility of using solar power to cover 50% of energy requirements of each school and the cost and payback period of the project are evaluated. The results of this paper provide insights regarding prioritizing energy efficiency projects in K-12 schools in humid subtropical climates and particularly the state of Florida and help with decision making regarding investment in on-site power generation using solar energy.

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