Design development of a static sunshade using small scale modeling technique

The rising global demand for energy has triggered emphasis on conservation of energy. Buildings are one of the important energy consuming sectors. Passive solar architecture encompasses a wide range of strategies and options resulting in energy efficient building design and increased occupant's comfort. Passive solar design, aiming at increasing direct solar gains during winter period and to avoid overheating during summer period should make use of specific shading devices over energy efficient window. The static sunshades are most effective for solar control inside the buildings.Countries like India have composite climate, which can be classified under summer, winter and rainy season. Depending on the seasonal requirements, this paper introduces a new geometry of a static sunshade, designed by calculating the sun angles for the two dates. The static sun shading design methodology is validated with the help of small scale modeling experimentation technique, carried out in Pilani, Rajasthan (India). Although insulating materials can be used as a part of a building structure, its feasibility should be checked before particular application. In the present paper, the two small-scale experimental models of actual construction material with varying static sunshades, i.e. horizontal and the proposed one have been constructed and analyzed with the models of insulating material (Polyurethane Foam [PUF]). Depending upon the solar intersection over south facade wall, sunlit area and shaded area have been correlated with temperature inside the models to decide the effectiveness of the proposed sunshade.     

A review of the current status of small-scale seawater reverse osmosis desalination

The current status of small-scale desalination (produced water capacity 100 m³/day or less) is reviewed to provide an overview of the market segment. The use of energy-recovery devices in this market segment is also reviewed. We find that the Middle East accounts for the largest market share worldwide at present, and reverse osmosis is overwhelmingly dominant among the desalination technologies adopted. Implementation of energy-recovery devices at small scale is rare, which leads to relatively high energy consumption for small-scale seawater reverse osmosis desalination systems.     

Electric energy generation from small-scale solar and wind power in Brazil: The influence of location,area and shape

Power production from renewable sources is identified as one of the tools to attain sustainable development in economic and social terms in Brazil. Awareness of how to prioritize renewable energy sources and technologies becomes increasingly important. Solar and wind energy have been highlighted in this context as being clean, safe and also relatively mature technologies. In addition, they are also renowned for having great energy potential and allowing different mounting options for energy harvesting systems. This article seeks to contribute to the knowledge of the effects that the key attributes, location, area and shape, of a site can have on the potential of renewable generation. In order to incorporate these attributes into an integrated analysis, a comparison method is developed and subsequently applied in a case study for two Brazilian cities. Results indicate that the amount of energy obtained by a given power generation system can undergo large variations depending on the characteristics of attributes such as site location, area and shape. This variation may ultra-pass 200%, in some cases, which demonstrates the importance of a better understanding of the role of these attributes in determining energy production.     

Performance analysis of a steady flamelet model for the use in small-scale biomass combustion under extreme air-staged conditions

Small-scale biomass boiler development is often based on empirical methods resulting in high efforts for experimental test runs using several prototypes. CFD simulations are able to reduce both, development time and efforts for tests and prototypes, supposing that the models reliability is high and its computational effort is low. Extreme air-staging with an initial gasification stage and a subsequent fuel gas burnout in a downstream gas-burner is a promising new method to reduce NO_X and PM emissions in small-scale biomass boilers. Gasification conditions in the first combustion stage lead to high accumulation of gaseous tars in the fuel gas contributing challenges for combustion simulation because common CFD models use 2 or 3-step global methane reaction schemes to describe combustion chemistry. In this work, the performance of a computationally inexpensive steady flamelet model (SFM) together with a detailed reaction mechanism (18 species, 42 reactions) was scrutinized. In order to evaluate the performance of the SFM, two furnace designs were examined, running under different load shifts and various excess air ratio. Comparative numerical simulations were performed with classical species transport models. The numerical simulations and the experiments for validation were carried out on a wood-chip boiler with a heat output of 40 kW. Results show that flue gas temperature, flame shape, main flue gas concentrations and NO_X can be quantitatively predicted. The SFM shows also reasonable good predictions for CO variation trends. With the present approach, calculation time can be reduced by 90% compared to commonly used models (EDC). The SFM provides sufficiently accurate results within 24 h using a standard processor consisting of six cores (mesh size 1.5 million elements). Thus, the presented model is a perfectly suitable method for applied science and industrial research.     

多谐波源小电网的无源滤波技术应用

无源滤波器一般存在滤波频段窄、依赖系统阻抗特性等缺点,这使其应用于谐波频谱复杂、波动严重的电网变得十分困难。本文结合某多谐波源的区域电网上无源谐波治理的实际应用案例,详细描述了设计该套滤波装置的分析和仿真过程,并给出相关的治理效果,具有一定工程应用价值。     

基于TOD模式的高铁站区景观设计初探——以济南西客站为调研解析案例

在我国快速城市化进程中,近年来高铁站区的建设方兴未艾,城市与站区各方面的发展需求日益迫切。TOD模式作为协调城市交通与土地利用的有效途径,是一种较为理想的高铁站区发展模式。通过典型高铁站区的实地调研与问卷访谈,分析总结经验并结合TOD发展理念,建设性地提出TOD模式下的高铁站区景观设计策略,阐述相关设计内容,希望对现阶段我国高铁站区景观设计与站区TOD健康发展思路具有良好的启示。     

Institutionalized knowledge conflict in assessing the possible contributions of H2 to a sustainable energy system for the Netherlands

This paper reports on a stakeholder dialogue project on the possible contribution of hydrogen to the Dutch energy transition. Dialogue methodology aims at articulating and exploring competing perspectives, including views that are in the margin of the energy policy subsystem. Three dialogue groups explored trajectories labeled Hydrogen for Transport, Hydrogen for the Built Environment and Hydrogen in the existing natural gas grid. The groups identified barriers and opportunities for the trajectories through back casting and assessed its pros and cons as compared to a non-hydrogen alternative. Referees from abroad contributed to a confrontation workshop, where the groups exchanged and discussed their first findings. The dialogue reveals that stakeholders are strongly divided with respect to small-scale domestic as well as the concept of a flexible natural gas infrastructure. We find a conflict between knowledge claims that either support or challenge the status quo. This is referred to as institutionalized knowledge conflict.     

Increase of stress intensity near interface edge of elastic-creep Bi-material under a sustained load

The transition from small-scale creep to large-scale creep ahead of a crack tip or an interface edge with strong elastic stress singularity at the loading instant causes stress relaxation and the decrease of stress intensity in general. However, this study shows that the stress near the interface edge of bi-material with no or weak elastic stress singularity increases after the loading instant and brings about the stress concentration during the transition. In addition, the creep strain distribution of this bi-material after the loading instant is different from that occurred in the transition of an interface edge with strong elastic stress singularity or a crack tip (notch root). The criterion for the increase or decrease of stress intensity near the interface edge proved by the finite element method is proposed in this study. The stress intensity near the interface edge increases when the elastic stress singularity is lower than the creep stress singularity (λ^el < λ^cr) and vice versa.     

Palm kernel shell as fuel for burning bricks

The use of an agricultural waste product, palm kernel shell, as a fuel for firing bricks is explored as a means of reducing environmental degradation and depletion of scarce firewood in Ghana. A simple but efficient methodology of clamp firing bricks using the new fuel is developed and tested. The resulting bricks are analysed for physical properties and suitability for construction use. The viability of palm kernel shell as a fuel for small-scale brick industries is considered. On etudie actuellement au Ghana les possibilites d'utilisation d'un dechet agricole, en l'occurrence, les coquilles de noix de palme, comme combustible dans les briqueteries; une telle solution permettrait de reduire la degradation de l'environnement et de diminuer l'appauvrissement des maigres reserves en bois de chauffage du pays. A cet effet, on met au point une methodologie simple mais efficace de cuisson des briques en brulant des dechets de coquilles de noix de palme. On analyse les proprietes physiques de ces briques et on verifie qu'elles conviennent a la construction. On etudie la viabilite de la coquille de noix de palme pour l'alimentation en combustible des petites briqueteries.     

Efficacy of solar power units for small-scale businesses in a remote rural area, South Africa

Much work has considered the practicalities and affordability of solar systems for domestic energy supplies in remote rural areas. There is less understanding of its utility for small-scale business enterprises in such areas. We examined the patterns of use of two 12 V and one 24 V systems for small-scale enterprises housed in transportable containers. Monitoring of load shed and top of charge indicated that the 12 V systems were inadequate to meet the requirements of the enterprises. The 24 V operation performed a lot better. Despite some technical limitations the system offered a number of social, economic and environmental positives; primarily the offering of business products not otherwise available in the area, incomes to the entrepreneurs and greater connectivity with regional centres through office services such as cell-phone charging and faxing. Customers of the small-scale enterprises felt that their presence in the area saved them some money because they no longer had to travel as frequently to regional urban centres.