Optimisation of the hybrid renewable energy system by HOMER,PSO and CPSO for the study area

This study is based on simulation and optimisation of the renewable energy system of the police control room at Sagar in central India. To analyse this hybrid system, the meteorological data of solar insolation and hourly wind speeds of Sagar in central India (longitude 78°45′ and latitude 23°50′) have been considered. The pattern of load consumption is studied and suitably modelled for optimisation of the hybrid energy system using HOMER software. The results are compared with those of the particle swarm optimisation and the chaotic particle swarm optimisation algorithms. The use of these two algorithms to optimise the hybrid system leads to a higher quality result with faster convergence. Based on the optimisation result, it has been found that replacing conventional energy sources by the solar–wind hybrid renewable energy system will be a feasible solution for the distribution of electric power as a stand-alone application at the police control room. This system is more environmentally friendly than the conventional diesel generator. The fuel cost reduction is approximately 70–80% more than that of the conventional diesel generator.     

利用进水余压供水

对国内普遍存在的一种由于供水工艺不合理所造成的能源浪费现象进行了分析,并提出了解决方案,结合有关实例分析了进水余压利用的方法及产生的经济效益。     

Effect of ventilation strategies on air contaminant concentrations and energy consumption in buildings

Considering the diversity of indoor contaminant characteristics and generation patterns, finding an appropriate ventilation strategy that can secure acceptable indoor air quality with minimum energy consumption is a challenging task for HVAC system designers and operators. This study theoretically models and investigates the impact of various ventilation strategies on contaminant concentration behaviour and corresponding ventilation cooling energy requirements for a single‐zone enclosure. Two types of contaminants are considered; carbon dioxide as an occupancy dependent and formaldehyde, which is independent of occupancy. An airflow model is used to predict space pressure and air leakage rates across the enclosure envelope, and an air quality model is used to predict time‐varying contaminant concentrations. In addition, a building energy simulation model is utilized to predict the corresponding ventilation cooling energy requirements under hot climatic conditions. Results from this study show that acceptable contaminant concentrations during occupied periods can be achieved by different ventilation strategies but at substantially different ventilation energy requirements. More than 50 per cent reduction in ventilation energy requirements can be obtained while maintaining acceptable IAQ if proper ventilation strategy is employed. Copyright © 2001 John Wiley & Sons, Ltd.     

Integrating waste and renewable energy to reduce the carbon footprint of locally integrated energy sectors

Energy use continues to rise and with it the emissions of CO₂. Energy efficiency methods have been applied across sectors. Efficiency gains and energy use per manufactured unit have fallen, particularly in relation to the processing industry. Residential, work place, leisure, and service sectors still use large amounts of energy and produce large emissions of CO₂ despite efficiency gains. Successful strategies used in the processing industry for integrating energy systems, namely Total Site targeting, have been applied to locally integrated energy sectors. The method shows that it can be successfully applied to integrate renewables into the energy source mix and consequently reduce the carbon footprint of these locally integrated energy sectors.     

Forecasting of Turkey's net electricity energy consumption on sectoral bases

In this study forecast of Turkey's net electricity energy consumption on sectoral basis until 2020 is explored. Artificial neural networks (ANN) is preferred as forecasting tool. The reasons behind choosing ANN are the ability of ANN to forecast future values of more than one variable at the same time and to model the nonlinear relation in the data structure. Founded forecast results by ANN are compared with official forecasts.     

能源审计工作推进节能降耗进程

阐述能源审计的概念及实施能源审计的作用,简单介绍能源审计的发展及我国实施能源审计所涵盖的内容,探讨广东省开展能源审计工作所存在的问题,针对其节能环节提出建议。     

多污染热源置换通风的应用与节能

简述了多污染热源置换通风的原理、特性及其与混合通风的比较 ,列举了工程应用实例 ,并对其节能效果进行了分析讨论 ,指出多污染热源置换通风是一种值得推广的通风方式     

Investigation of PEM electrolyzer modeling: Electrical domain,efficiency, and specific energy consumption

Proton exchange membrane (PEM) electrolyzer is an advanced technology considered a viable alternative for the generation of hydrogen-based on renewable energy sources (RES). Its modeling is essential to study its interaction with RES and power electronics. In the current literature, the models for the electrical domain are mainly based on semi-empirical and empirical equations. However, dynamic operations are generally neglected. Besides, a few works about electrolyzer efficiency have been reported, especially Faraday's efficiency, which is a key parameter to express the losses due to gas diffusion. The main purpose of this review is to summarize and analyze the reported models to describe the electrical domain. Furthermore, dynamic operation issues are highlighted and recent works about modeling the dynamics are introduced. Finally, a discussion is provided about the different efficiency (Faraday, voltage, energy) and the specific energy consumption, which are important indicators linked with the performance.     

What are the energy and power consumption patterns of different types of built environment?

This paper outlines the current energy usage patterns of various sectors of activity within the built environment. It then leads on to identify drivers and barriers to how energy consumption within the built environment could be reduced in the future.     

Barriers' and policies' analysis of China's building energy efficiency

With the rapid economic growth and the improvement of people's living standards, China's building energy consumption has kept rising during the past 15 years. Under the effort of the Chinese government and the society, China's building energy efficiency has made certain achievements. However, the implementation of building energy efficiency in China is still far from its potential. Based on the analysis of the existing policies implemented in China, the article concluded that the most essential and the most effective ways to promote building energy efficiency is the government's involvement as well as economic and financial incentives. In addition, the main barriers in the process of promoting building energy efficiency in China are identified in six aspects. It has been found that the legal system and administrative issues constitute major barriers, and the lack of financial incentives and the mismatching of market mechanism also hamper the promotion of building energy efficiency. Finally, in view of the existing policies and barriers analysis, three corresponding policy proposals are presented.     

电动汽车的能耗效率分析及提高能耗经济性的研究

通过对比电动汽车和内燃机汽油车的热效率及能耗,得出电动汽车的热效率及能耗明显优于内燃机汽油车的结论,并推断出降低电动汽车的运行能耗、提高其经济性是推动电动汽车产业化的关键因素之一。从整车动力系统、电池以及充电设备等几个方面分析了提高电动汽车能耗经济的途径,指出了今后需要重点研究的关键性问题。     

Integration properties of disaggregated solar,geothermal and biomass energy consumption in the U.S.

This paper investigates the integration properties of disaggregated solar, geothermal and biomass energy consumption in the U.S. The analysis is performed for the 1989–2009 period and covers all sectors which use these types of energy, i.e., transportation, residence, industrial, electric power and commercial. The results suggest that there are differences in the order of integration depending on both the type of energy and the sector involved. Moreover, the inclusion of structural breaks traced from the regulatory changes for these energy types seem to affect the order of integration for each series.     

Effective use of surplus LP steam to maximize cracker throughput and reduce energy consumption

Steam cracking is a fundamental application of olefin production which is the building block of petrochemical complex. Continuous efforts are being made to optimize the cracker performance by process-side optimization. The cracker furnace flue gas, which has a huge quantum of low-grade energy, is getting lost from the stack; a waste heat recovery system is being employed to generate ow-pressure steam. This also helps in the reduction of induced draft fan suction temperature. However, if there are no low-pressure steam consumers, the steam requires to be vented or partial heat recovery to be done. The lower heat recovery through waste heat recovery boiler restricts the cracking furnace throughput due to a higher suction temperature of the induced draft. A detailed steam network study has been done for a petrochemical complex having various downstream plants to maximize heat recovery as well as furnace throughput. For any equipment in question, to use a lower steam, it was a challenge to switch over from relatively higher-pressure steam to lower-pressure steam due to equipment design consideration as well as operating temperature requirement of any process. Different alternatives were thought of and evaluated based on process requirement, possibility of steam venting of other level steam, and cost of modifications. The outcome of this study has helped to utilize the low-pressure steam. The study indicated that for optimization of cracker performance, in addition to process side, there is a scope to improve on flue gas side operation also.     

Energy saving by integrated control of natural ventilation and HVAC systems using model guide for comparison

Integrated control by controlling both natural ventilation and HVAC systems based on human thermal comfort requirement can result in significant energy savings. The concept of this paper differs from conventional methods of energy saving in HVAC systems by integrating the control of both these HVAC systems and the available natural ventilation that is based on the temperature difference between the indoor and the outdoor air. This difference affects the rate of change of indoor air enthalpy or indoor air potential energy storage. However, this is not efficient enough as there are other factors affecting the rate of change of indoor air enthalpy that should be considered to achieve maximum energy saving. One way of improvement can be through the use of model guide for comparison (MGFC) that uses physical-empirical hybrid modelling to predict the rate of change of indoor air potential energy storage considering building fabric and its fixture. Three methods (normal, conventional and proposed) are tested on an identical residential building model using predicted mean vote (PMV) sensor as a criterion test for thermal comfort standard. The results indicate that the proposed method achieved significant energy savings compared with the other methods while still achieving thermal comfort.     

The multiple selections of fostering applications of hydrogen energy by integrating economic and industrial evaluation of different regions

There are three major applications (portable, stationary, transportation) of hydrogen energy (HE), and each application play a unique and important role in the sustainable development of energy system. In different regions within a country, different applications of HE are preferred. This paper therefore explores the process to decide the optimal region to develop each of the three subtypes of HE applications. To this end, the Analytical Hierarchy Process (AHP) and a fuzzy Technique the Order of Preference by Similarity to Ideal Solution (TOPSIS) method are used in the present study. Based on a literature review and in-depth interviews with officers, experts, the managers of HE-related enterprises, and consumers, the present study comes up with two selection criteria, namely, the acceptance on the applications of hydrogen energy (i.e., market entry barriers and customer's acceptance), and the integrity of hydrogen energy industrial chain on three applications (i.e., production stage, distribution stage, and marketing stage). This paper uses a case study to explore the functioning of three applications of hydrogen energy in the industrial, cultural and restricted residence regions. Four main findings emerges from this study: (1) the market structure of the portable, stationary and transportation application of HE should be pure competitive, oligopolistic, and monopolistic competition respectively; (2) the customer's acceptance for different applications is different, due to different neighborhood concerns about the quality of life; (3) the cost and benefit of different applications depend on different factors, including government policy, technological improvements and social preferences; (4) in order to promote all HE applications, the process to decide the optimal region to develop a specific HE application depends on the comparative advantages of the application.     

Analysis of energy and carbon dioxide emission caused by power consumption

The main objective of this on‐site study is to use a full‐scale Heating, Ventilating, and Air‐Conditioning (HVAC) system installed in an office building in Taiwan for comparing the power consumption, energy‐saving, and carbon dioxide (CO₂) reduction of two different strategies for controlling the HVAC. These strategies are the Constant Volume (CV) system [Constant Air Volume+Constant‐flow], and the Variable Volume (VV) system [Variable Air Volume +Variable‐flow]. The on‐site experimental results indicate that average power consumptions are 164 kW for the CV system, and 88 kW for the VV system; the average electric current drops from 469 A for the CV system to 258 A for the VV system. Approximately 46% of the average energy‐saving can be achieved if the HVAC system is operated as a VV system. Additionally, the reduced quantity of accumulated CO₂ emission varies from 67 to 3687 kg with 0.637 kg CO₂ kwh^?1 emission factor during the office hours of 08:30 (a.m.)–17:00 (p.m.). The results demonstrate that switching the operation of an office building HVAC system from CV to VV will significantly enhance energy‐savings and CO₂ reduction. This studywill offer useful information for evaluating an indoor environmental policy with respect to energy‐savings and CO₂ emission reduction for office HVACs used in subtropical regions. Copyright © 2010 John Wiley & Sons, Ltd.     

Assessment of China's climate commitment and non-fossil energy plan towards 2020 using hybrid AIM/CGE model

China made a commitment in Copenhagen to reduce its carbon dioxide emissions per unit of GDP from 40% to 45% compared with the 2005 level by 2020, and is determined to vigorously develop non-fossil fuels. This study analyzes the effects and impacts of policies that could help to achieve China's Copenhagen commitments with a hybrid static CGE model in which the electricity sector is disaggregated into 12 generation technologies. Four scenarios are developed, including the reference scenario A, the reference scenario B and two carbon constraint scenarios. The results show that carbon intensity in terms of GDP will fall by 30.97% between 2005 and 2020 in the reference scenario A, and will be reduced further by 7.97% if China's targeted non-fossil energy development plans can be achieved in the reference scenario B. However, the rest of the 40–45% target must be realized by other measures such as carbon constraint. It is also observed that due to carbon intensity constraints, GDP loss would be from 0.032% to 0.24% compared to the reference scenario B, and CO₂ emission reductions are due mainly to decreases in coal consumption in the electricity sector and manufacturing sector.     

Optimisation and techno-economic analysis of autonomous photovoltaic–wind hybrid energy systems in comparison to single photovoltaic and wind systems

A techno-economic analysis for autonomous small scale photovoltaic–wind hybrid energy systems is undertaken for optimisation purposes in the present paper. The answer to the question whether a hybrid photovoltaic–wind or a single photovoltaic or wind system is techno-economically better is also sought. Monthly analysis of 8 year long measured hourly weather data shows that solar and wind resources vary greatly from one month to the next. The monthly combinations of these resources lead to basically three types of months: solar-biased month, wind-biased month and even month. This, in turn, leads to energy systems in which the energy contributions from photovoltaic and wind generators vary greatly. The monthly and yearly system performances simulations for different types of months show that the system performances vary greatly for varying battery storage capacities and different fractions of photovoltaic and wind energy. As well as the system performance, the optimisation process of such hybrid systems should further consist of the system cost. Therefore, the system performance results are combined with system cost data. The total system cost and the unit cost of the produced electricity (for a 20 year system lifetime) are analysed with strict reference to the yearly system performance. It is shown that an optimum combination of the hybrid photovoltaic–wind energy system provides higher system performance than either of the single systems for the same system cost for every battery storage capacity analysed in the present study. It is also shown that the magnitude of the battery storage capacity has important bearings on the system performance of single photovoltaic and wind systems. The single photovoltaic system performs better than a single wind system for 2 day storage capacity, while the single wind system performs better for 1.25 day storage capacity for the same system cost.     

Reduction of CO2 capture plant energy requirement by selecting a suitable solvent and analyzing the operating parameters

Among various developed methods for CO₂ capturing from industrial flue gases, chemical absorption system is still considered as the most efficient technique, because of its lower energy requirement and also its applicability for low concentration of CO₂ in the inlet gas stream. Also, it can be used to retrofit the existed power plants, which are the major industrial CO₂ emission sources, without changing their design condition. Selection of a suitable solvent is the first parameter that should be considered in the design of capture plants that use absorption technology. The most important challenge for using chemical solvents is finding the optimum operating conditions to minimize the energy requirement. Study of technical parameters can be helpful to improve the overall capture plant efficiency. In this paper, CO₂ capture plant has been simulated for different solvents to compare their performance and energy requirement. To improve the plant overall efficiency, effect of the main operating factors such as amine flow rate, temperature, inlet gas temperature, and pressure has been studied in this paper. This analysis indicates the best chemical solvent for various cases of inlet flue gas. This parametric study reduces the overall energy requirement and helps design a cost‐effective plant. Copyright © 2012 John Wiley & Sons, Ltd.     

Comparative study of energy consumption and CO2 emissions between Beijing and London

From the view of geographic location, climate and population status, this paper makes a comparative study of the economy structure, transport system, energy supply and carbon emissions among a few cities, especially between Beijing and London, two mega-cities in the world. The developed tertiary industry, consummate transport system and low-carbon energy supply system in London can be referenced to assist Beijing in establishing a low-carbon development pathway. The difference in the statistical coverage of population between these two cities also brings about the divergence of energy consumption per capita and CO? emissions per capita between them.