商业照明环境与节能潜力分析

在商业建筑中 ,照明能耗约占到建筑总能耗的 1/3,照明节能是商业建筑节能的重要环节。本文分析了商业照明环境与消费行为的关系 ,指出营造一个良好的照明环境能促使消费行为的完成 ,但同时还应该重视照明系统的节能功能 ;分析了照明节能的四个途径 :光源的合理选择、自然光的合理利用、空间照度的合理设计和照明系统的合理控制与管理     

The study of factors that influence on the effectiveness of the photoconversion of <Emphasis Type="Italic">n</Emphasis>-CdS/<Emphasis Type="Italic">p</Emphasis>-CdTe heterostructures

The load characteristics of n-CdS/p-CdTe heterostructures were studied at different lighting levels with monochromatic light (λ = 632.8 nm) and white light with different spectra of radiation. It was established that the efficiency of conversation of a structure increases with increased temperature upon lighting with white light from an incandescent lamp. The results will help to optimize the structure of photocells based on CdTe polycrystalline films.     

An ANFIS-RSM based modeling and multi-objective optimization of syngas powered dual-fuel engine

The present study investigates the possibility of increasing efficiency and lowering pollutant emissions from a syngas-powered engine by modulating operational parameters such as engine load and syngas composition. Although artificial intelligence-based technologies are becoming more common for modeling single-fuel mode engines, they are rarely employed to simulate a dual-fuel syngas/diesel engine. In the first of its kind Endeavor in the area of syngas fueled engines, a hybrid adaptive neuro-fuzzy inference system (ANFIS)-response surface methodology (RSM) is investigated. The performance of syngas (H₂+CO), a novel synthetic gaseous fuel, was studied in four different combinations. ANFIS and RSM-based prediction models were developed using engine performance and emissions data collected over the whole load range. While ANFIS surpassed RSM in model prediction, RSM was useful in establishing mathematical links between engine input and output. The ANFIS model developed had a good correlation between R (0.996–0.9998) and R² (0.992–0.9972), as well as low model errors as determined by the root means square error range (0.0086–5.936) and mean absolute percentage error range (0.0028–0.0194). Theil's U2 was used to calculate the model's uncertainty, which was estimated to be 0.0065–0.0439. The superior forecasting abilities of ANFIS models were proved by low errors and uncertainty. The performance of the syngas-powered engine was optimized using the desirability approach to achieve optimum efficiency while emitting the least amount of pollution. The ideal engine load and syngas compositions for maximum production were 67.99% engine load and 72.4:27.6 as H₂:CO syngas mix.     

New Technologies for Rural Lighting in Developing Countries: White LEDs

Most of the third-world rural areas, especially in sub-Saharan Africa, are still without electricity. The few existing off-grid and upcoming installations are remote and characterized by limited resources that call for drastic conservation measures. For the majority of these emerging consumers, lighting is the priority load. Rural electrical lighting load models are characterized by inaccuracies due to technical omissions, highlighted in this paper, and result in energy wastage. Solutions to the third-world problems need not follow similar paths to those of the developed world. In fact, cutting-edge technologies like the cell phone have already leapfrogged rural communications where expensive infrastructure had been perennially cited as the impediment. In this paper, another futuristic technology, the white light emitting diode (LED), for general lighting, is poised to create yet another revolution in African rural electrification.     

Recycling mobile phone batteries for lighting

The fast evolution of technology and over production of mobile electronic devices leads to their short usage period and therefore may be a source of environmental pollution and contributes to global warming. Fortunately, due to the properties of the lithium ion (Li-ion) battery that powers these mobile devices, there is a lot of life left for the battery when the device is sent to recycle. This e-waste can be valued by giving to the batteries a second life as energy storage for solar lighting. In fact, it can be a real opportunity for access to electricity in remote rural areas of developing countries for low cost and quality lighting. We show that the usage of recycled mobile phone batteries associated with a solar panel and a light emitting diode (LED) lamp can be a good replacement for candles and kerosene lamps that are hazardous and only give poor lighting quality. Such a replacement can be done for a much lower cost than current expenses, better quality of light and contributes to poverty alleviation and jobs creation. This overcomes the challenges of cost and durability in small off-grid photovoltaic systems.     

New component for daylighting: first italian application of a sun duct

The use of daylighting in a room is certainly better than the use of lamplight alone, due to its undubitable chromatic properties and correlated psychological effects. In many cases, especially for pre-existing buildings, the income of daylighting appears an unsolvable problem forcing people to use intensively electric lighting. In this paper the use of a component for natural lighting of a space with no direct openings to the exterior is presented. The project was carried out in a building situated in the old town centre of S. Colombano al Lambro near Milan.     

The traditional Yemeni window and natural lighting

The traditional Yemeni window is considered to be one of the most important elements that characterize the yemeni architecture. The beauty of the traditional Yemeni window comes from its four main components which combined the functions of view, lighting, ventilation, protection, and privacy. These functions can be controlled by the occupants according to their social and environmental needs. The four main components are the lower part (Taqah), the fanlight (Qamariyah), the wooden external overhang (Konnah), and the small vent (Shaquos). Since fanlights provide natural lighting during day-time, the area of the lower part can be reduced and its exterior shutters can be closed without the need for artificial lighting. The internal natural lighting that is provided by the upper and lower parts of the window was investigated to see its quality. In this investigation, there were two main goals. The first is the contribution and quality of the internal light provided by the Qamariyah when shutters are closed. The second is the effect of the internal simple white cloth curtains, in the lower part, in the internal light quality. Visual measurements were taken in a typical room of a traditional house of the Old City of Sana'a, Yemen. From the findings, it was found that the fanlights (Qamariyat) provide low and soft homogeneous internal lighting which was as low as 22 lux average. However, the occupants have the ability to increase level of lighting to as high as 600 or 700 lux. This can be done simply by deciding which shutter to open and how many of them to be opened. In this paper, the methodology and findings will be presented and discussed.     

Experimental investigation of high temperature congregating energy solar stove with sun light funnel

A solar stove which uses a light funnel to guide light and congregate solar energy has been designed. Its structure and operation principle have been introduced. The performance tests under the real weather have been carried out and the graphic lines of experiment have been given. The experimental result shows that the maximum temperature inside the stove is as high as 250 °C under the condition of 1.5 m² of lighting area, 70% reflectivity of reflecting aluminum foil inside surface of concentrator and no load (without water inside the coil pipe). When reflectivity is 86% the heat collecting efficiency of the device is about 43%. The collecting power that the stove receives can be up to 500 W. It is an ideal medium and high temperature solar energy congregating device suitable for industrial usage or cooking and other domestic usage.     

Residential energy-efficient lighting adoption survey

Artificial lighting has transformed how humans relate to the world, by improving productivity and making spaces habitable. The adoption of energy-efficient solid-state lighting, light emitting diodes (LED), has been suggested as a way of reducing energy used for lighting. Such predictions rest on the assumptions of constant light density and time of use in the future, assumptions not supported by past trends. In order to better understand how consumers choose to adopt energy-efficient artificial lighting for their homes; a survey was administered in four major urban areas: Chicago, Houston, New York, and San Francisco. Major insights from the survey indicate that if lighting becomes less expensive through adopting energy-efficient light sources, there is the potential for consumers to use considerably more, and the point at which the price for LED lighting yields broad market penetration is about one half of current prices. Regional factors such as lighting subsidies, taxation policies, laws, and educational information are also explored.     

An analysis of lighting energy savings and switching frequency for a daylit corridor under various indoor design illuminance levels

Visual comfort and electric lighting energy issues are essential criteria to justify daylighting schemes. The evaluation of energy efficiency due to daylight linked lighting control systems is best demonstrated by case studies. This paper presents field measurements on daylighting for a fully air-conditioned daylit corridor. Artificial lighting load, brightness of the fluorescent luminaires, daylight availability for various switching illuminance levels were systematically recorded and analyzed. The general features and characteristics of the findings including the number of switching operations and electric-lighting energy savings are presented and discussed. Daylighting theories, using cumulative frequency distribution of outdoor illuminance and regression models based on brightness of light output, outdoor illuminance and electric light power to estimate daylight-linked lighting control savings, have been developed and assessed. It has been found that data from both approaches show reasonably good agreements with measured results. The findings from this study provide some operational and energy information, which would be useful and applicable to other interior spaces with similar architectural designs.     

Modern residential energy inequalities in Indonesia: spatial and income analyses

ABSTRACT

This study put forward the inequality issues in modern residential energy consumption from both income and spatial viewpoints, with special regard to the Indonesian case. Energy inequality was viewed from the perspective of energy justice in both distribution and recognition. This study employed qualitative analysis with Theil’s, Gini, and mixed-Gini index methods. The energy usage inequalities have declined, both overall and by the dimensions of spatial and income levels, except in urban areas. However, this paper found that some groups were susceptible to fall into energy-poor, especially residents in rural areas, remote areas, and eastern Indonesia. Besides improving a more stable electricity grid, the government should continue the energy-saving solar lighting (LTSHE) program and promote small-scale decentralized technologies. LPG distribution should be improved. A program such as the cheap clean stove needs to be developed to reach those without access to clean cooking fuel.     

A ladder within a ladder: Understanding the factors influencing a household's domestic use of electricity in four African countries

According to the energy ladder hypothesis, electricity is at the top of the energy ladder of household energy use that depends primarily on wealth status, income and education levels of the users. However, it is often observed that households with higher income, wealth, and education levels do not use electricity for all domestic activities such as lighting, heating, and cooking, creating a ladder within a ladder. Using a comprehensive data set from the Living Standard Measurement Study from four African countries (Ethiopia, Malawi, Tanzania and Uganda), covering > 17,000 households, this paper investigates the factors determining a household's adoption of electricity for lighting only and for lighting and cooking. The results of a multinomial logit model and an ordered probit model show that demographic characteristics, a household's wealth and human capital, access to markets and remoteness greatly accelerate a household's use of electricity for light and cooking, which provides evidence of a ladder within a ladder.     

引进日光 关掉电灯

公共建筑自然采光的意义不仅在于节省照明能耗,减少碳排放,而且为室内的视觉作业提供舒适、健康的光环境,是良好的室内环境质量不可缺少的重要组成部分。文章介绍了新型自然采光技术——管道式日光照明装置,在与灯光照明、传统天窗采光和光纤集光照明等的比较中说明管道式日光照明装置的技术原理、结构功能和应用。     

The effect of boost pressure on the performance characteristics of a diesel engine: A neuro-fuzzy approach

This paper uses a neuro-fuzzy interface system (ANFIS) to study the effect of boost pressure on the efficiency, brake mean effective pressure (BMEP), and the brake specific fuel consumption (BSFC) of a single cylinder diesel engine. Experimental data were used as inputs to ANFIS to simulate the engine performance characteristics. The experimental as well as the model results emphasize the role of boost pressure in improving the different engine characteristics. The results show that the ANFIS technique can be used adequately to identify the effect of boost pressure on the different engine characteristics. In addition, different data points that were not used for ANFIS training were used to validate the developed models. The results suggest that ANFIS can be used accurately to predict the effect of boost pressure on the different engine characteristics.     

Robust MACCs? The topography of abatement by fuel switching in the European power sector

This paper employs a simulation model of the European power sector to analyze the abatement response to a CO₂ price through fuel switching, one of principal means of reducing greenhouse gas emissions in any economy. Abatement is shown to depend not only on the price of allowances, but also and more importantly on the load level of the system and the ratio between natural gas and coal prices. The interplay of these different determinants vitiates any simple relation between a CO₂ price and abatement and requires the development of more than two-dimensional graphics to illustrate these complex relationships. In the terms of the literature on the use of marginal abatement cost curves (MACCs), we find that these MACCs are not robust as usually defined and we suggest that the more complex topography developed in this paper may be more helpful in visualizing this abatement response to a CO₂ price.     

A comparative assessment of predicting CH4 adsorption on different activated carbons using generalized regression neural network (GRNN), and adaptive network-based fuzzy inference system (ANFIS)

The aim of this work is to predict the adsorption of methane on various activated carbon using to intelligent models including Generalized Regression Neural Network (GRNN), and adaptive network-based fuzzy inference system (ANFIS). Methane is the major component of natural gas, coal bed gas, and some exhaust gases of petrochemical or chemical units. Therefore, a fundamental study on the adsorption was encouraged by engineering concerns. In this regards, the precise prediction of CH₄ adsorption is of great interest and importance. The model is developed using a comprehensive database obtained from the literature. The outcomes of the model were compared with the experimental data. The values of the statistical parameters R², RMSE, and AARD% reveal that the ANFIS model is more accurate. Results showed that the developed model accurately predicts CH₄ adsorption on activated carbons with an overall R² and AARD% values of 0.921% and 0.657%, respectively.     

A marketable all-electric solar house: A report of a Solar Decathlon project

This paper reports a design and building process of a net-zero-energy modular house, named ElementHouse, which was entered for the 2007 Solar Decathlon competition that was organized by the U.S. Department of Energy. This paper discusses the development of the ElementHouse from its initial concept to the actual construction, which integrated multi-disciplinary knowledge of architecture, mechanical engineering, and electrical engineering. By employing computer-aided simulation tools, several design approaches were developed to achieve the optimal balance among function, aesthetics, economy, and energy—a challenge in many sustainable building designs. A simplified energy model helped to form the building configuration at the preliminary design stage by showing how energy use is affected by various parameters, leading to optimization studies that provided design guidelines towards an energy-efficient building envelope and opening design. Energy modelling also estimated the annual energy use and electricity generation, as well as the costs associated with long-term operation of the house. The energy demand estimate and its daily power profile helped to design the photovoltaic (PV) system. The modular configuration of the building and its roof structure was then iteratively altered to accommodate the PV panels in such a way as to generate the most power and to facilitate interstate transportation of ElementHouse. With the progress of the design process, detailed energy simulation using EnergyPlus provided more accurate estimates of power use and generation and, coupled with daylighting simulation performed with Radiance, permitted finalizing the building envelope, opening, and electric lighting design. The building envelope embraced the passive and low energy philosophy to minimize the annual heating and cooling load and to optimize natural lighting. By illustrating the whole picture of ElementHouse design, this paper discusses a way of effectively designing and building a comfortable and affordable solar house.     

Reactive power compensation of an isolated hybrid power system with load interaction using ANFIS tuned STATCOM

This paper presents an adaptive neuro fuzzy interference system (ANFIS) based approach to tune the parameters of the static synchronous compensator (STATCOM) with frequent disturbances in load model and power input of a wind-diesel based isolated hybrid power system (IHPS). In literature, proportional integral (PI) based controller constants are optimized for voltage stability in hybrid systems due to the interaction of load disturbances and input power disturbances. These conventional controlling techniques use the integral square error (ISE) criterion with an open loop load model. An ANFIS tuned constants of a STATCOM controller for controlling the reactive power requirement to stabilize the voltage variation is proposed in the paper. Moreover, the interaction between the load and the isolated power system is developed in terms of closed loop load interaction with the system. Furthermore, a comparison of transient responses of IHPS is also presented when the system has only the STATCOM and the static compensation requirement of the induction generator is fulfilled by the fixed capacitor, dynamic compensation requirement, meanwhile, is ful-filled by STATCOM. The model is tested for a 1% step increase in reactive power load demand at t = 0 s and then a sudden change of 3% from the 1% at t = 0.01 s for a 1% step increase in power input at variable wind speed model.     

PEM fuel cell supported distribution static compensator for power quality enhancement in three-phase four-wire distribution system

One of the major problems in electrical power system is the lack of quality of power due to the rapid growth of nonlinear load and unbalanced load utilization in three-phase four-wire distribution system. In this paper, PEM (Proton Exchange Membrane) fuel cell supported four-leg Distribution Static Compensator (DSTATCOM) is modelled to mitigate harmonics, neutral current and load balancing under nonlinear load and unbalanced load conditions in three-phase four-wire distribution system. The instantaneous reactive power (IRP) theory control algorithm is proposed for four-leg DSTATCOM. The Real coded Genetic Algorithm (RGA) optimized Proportional Integral (PI) controller and Adaptive Neuro Fuzzy Inference System (ANFIS) controller are used for regulating the DC link voltage of DSTATCOM. This paper also investigates the performance of ANFIS based DSTATCOM with conventional method. The proposed system is modelled and its performance is analyzed in MATLAB/SIMULINK.     

DAYLIGHTING TECHNOLOGIES IN NON-DOMESTIC BUILDINGS

Natural daylight is an inexpensive and very efficient light source provided that the amount of daylight entering a building is controlled according to demand. In commercial buildings electricity for lighting can be cut by 50-75% using daylighting design techniques in combination with efficient artificial lighting. New lighting control technologies and advanced computer simulation tools lo optimize large buildings makes it possible to exploit these energy savings.

Daylight is a very efficient light source, providing more light for less input of thermal energy than any other artificial light source. Efficient shading systems are now emerging systems that can control the admission of daylight to the room according to requirement, and avoid overheating. Some of these systems, such as reflective light shelves, will also contribute to a better distribution of the daylight available by redistributing some daylight to the back of the room. However, more work is needed to develop and test such combined daylight and shading systems.

The use of daylight to reduce electric lighting must be seen as an integrated part of the overall energy optimization of the building. An efficient control of the use of daylight and artificial lighting will not only reduce electricity use for lighting. Additionally, the use of electricity for ventilation and cooling can be reduced also, because the internal heat gains provocating these electricity uses are reduced. This calls for an integrated design approach to the overall energy design of the building, involving the architect and the engineer from the very beginning of the design phase.

Visual comfort of office buildings receives increasing attention, partially because of the VDU's (Visual Display Units) of the computers, that are now almost standard equipment of every work place. The performance requirements for both daylighting systems and artificial lighting systems have been sharpened, and the attention to this fact is crucial in future development of lighting systems.