The development of the bioclimatic concept in building design

The degree of accuracy of climate analysis is of great importance in the bioclimatic concept of building design. The accuracy of utilized methodology in the climate analysis pre-design step is reflected later in the degree of accuracy, and to a certain extent, the validity of the final proposal of the bioclimatic design. The Climate Model Year (CMY) methodology is proposed as an accurate tool for the analysis and modelling of all the climate parameters involved in bioclimatic design. The Model Year Climate Mapping (MYCM) is also discussed as a time saving and climate prediction tool. The development of the bioclimatic concept of building design is discussed. Some of the most important works in this field are briefly presented. The proposed methods for climate analysis and modelling (CMY and MYCM) are combined with the Mahony Tables and the Building Bioclimatic Chart in order to produce more accurate designs. Applications of these combinations are presented at the end by considering the four climate zones of Saudi Arabia.     

Examination of HA230 turbine transition duct

Abstract

The present paper reports the results of an examination of a service run transition duct from one of Siemens' industrial gas turbines and the correlation between the findings for this, and those from the studies undertaken on laboratory exposed Haynes alloy 230 material. The studies have shown that there are changes in the microstructure and hardness of the material that can be related to temperature and time of exposure, and the information gained can lead to estimations of the average component operating temperature. Metallographic studies revealed a high level of heterogeneity of the grains in this transition duct.     

Renewable energy for sustainable urban development: Redefining the concept of energisation

It is widely recognised that access to and supply of modern energy play a key role in poverty alleviation and sustainable development. The emerging concept of energisation seems to capture this idea; however, there is no unified definition at the point of writing. In this paper, the aim is to propose a new and comprehensive definition of the concept of energisation. The chronological development of this concept is investigated by means of a literature review, and a subsequent critique is offered of current definitions and usage of the concept. Building upon these first insights, two planned cases of energisation in post-apartheid South Africa are contrasted to an unplanned one: they are the national electrification programme, the integrated energy centres initiative, and a wood fuelled local economy in Khayelitsha, Cape Town's biggest township. Especially the latter case, based on original data collection by the authors, provides a new understanding of specific elements affecting energisation. Finally, a new and detailed definition of the concept of sustainable energisation is developed by systematically reiterating three key elements: the target group, the concept of energy services, and sustainable development.     

Evaluation,degradation and life assessment of coatings for land based combustion turbines

Abstract

Use of metallic and thermal barrier coatings to protect hot section blades and vanes of combustion turbines for power generation has been common practice for the past three and one decades respectively. Because these coatings must be optimised with respect to both different forms of corrosion and modes of operation (base load versus peak load), their performance may be machine specific. Industrial end users generally do not have detailed knowledge of the failure mechanisms of the coatings and the basis for selecting coatings to suit specific requirements, topics the present review seeks to address. The evolution of protective coatings, coating failure mechanisms and a methodology for selecting machine specific coatings are described. The methodology, which can be used to rank and optimise coating systems and to predict the remaining life of coatings, forms the basis of a computer code known as COATLIFE. The ingredients of this methodology, i.e. degradation modelling and thermomechanical fatigue life prediction, are reviewed.     

坚持科学发展观着力打造环境友好型社会

景德镇市牢固树立科学发展观，着力打造环境友好型社会，通过加大投入、产业升级和健全法律法规等举措，统筹人与自然和谐发展。将曾经是“中国污染，景德镇为盛”的重度污染城市建设成为全国优秀旅游城市。实现了经济社会和生态环境协调发展双赢。     

以科学发展观协调发展江苏能源与社会经济

“九五”,以来,江苏能源发展取得了显著的成绩,但在实施传统工业化的过程中,社会生产力得到极大发展,同时也造成了能源资源的过量消耗和生态环境的破坏,能源短缺已经成为江苏经济社会可持续发展的瓶颈。要实施全面的能源战略,有效地开发和利用能源,缓解能源的供需矛盾,控制能源利用对生态环境的污染破坏,提高能源利用的经济效率和社会效益。     

Effect of some BED blends on the equivalence ratio, exhaust oxygen fraction and water and oil temperature of a diesel engine

Nowadays, natural-based oxygenated fuels, especially biodiesel and ethanol, have been considered as substitutes for fossil fuels. Because of relatively lower energy content of oxygenated fuels, it is necessary to blend them with fossil ones. In this research, authors conducted an investigation on some BED blends to determine and compare their effects on equivalence ratio, exhaust oxygen fraction and water and oil temperature in a diesel engine. For this purpose, 18 different blendes of ethanol and biodiesel with net diesel fuel were tested in a MT4-244 engine¹ considering two engine speeds in full load condition. In almost all samples the equivalence ratio decreased with increasing of biodiesel and ethanol percents. Exhaust oxygen fraction in all of samples increased with increasing of biodiesel and ethanol percents, whereas the engine water and oil temperatures slightly reduced.     

Hydrogen production by biomass gasification in supercritical water using concentrated solar energy: System development and proof of concept

A novel system of hydrogen production by biomass gasification in supercritical water using concentrated solar energy has been constructed, installed and tested at the State Key Laboratory of Multiphase Flow in Power Engineering (SKLMF). The “proof of concept” tests for solar-thermal gasification of biomass in supercritical water (SCW) were successfully carried out. Biomass model compounds (glucose) and real biomass (corn meal, wheat stalk) were gasified continuously with the novel system to produce hydrogen-rich gas. The effect of direct normal solar irradiation (DNI) and catalyst on gasification of biomass was also investigated. The results showed that the maximal gasification efficiency (the mass of product gas/the mass of feedstock) in excess of 110% were reached, hydrogen fraction in the gas product also approached to 50%. The experimental results confirmed the feasibility of the system and the advantage of the process, which supports future work to address the technical issues and develop the technology of solar-thermal hydrogen production by gasification of biomass in supercritical water.     

The thin film flexible floating PV (T3F-PV) array: The concept and development of the prototype

The paper presents the concept and design behind the thin film flexible floating PV (T3F-PV) array, aimed at offshore large scale generation. The development of such an array comprises of non-conventional application of thin film PV panels. There are some issues envisaged, primarily the electrical reliability of the panels were they are prone to water absorption. Also the presence of the water could lead to cooling which would be an advantage of the system. Analysis of these issues and a first stage towards the development of the concept was through the manufacturing and operation of a small scale prototype in an enclosed water body in Sudbury, Canada. The data gathered from a small scale prototype leads to an estimated 0.5% decrease in electrical efficiency after the 45 day testing period mainly due to sediment occlusion on the PV panels. The cooling effect of the water could be calculated to an averaged electrical improvement of 5% through a 3 day comparison test (conducted when the floating PV had been exposed to their water conditions for almost 3 months). Also a significant variation in electrical output could be noted if the floating panels were allowed to go just below the waterline or if they were designed to stay on top of it. Some changes to the design were discussed to improve the concept and lead it onto the next step in the development, with a larger scale installation operating in the open sea with harsher environments to be dealt with.     

Dual-receiver concept for solar towers

A new dual receiver concept improves the adaptation of the central receiver to the steam cycle in a solar thermal power plant. By combination of an open volumetric air heater with a tubular evaporator section the dual receiver concept profits from the advantages of these two basic concepts while their characteristic problems are avoided. This paper presents a concept study based on the configuration that was originally planned for the PS10 project in Spain, using the open volumetric receiver technology. The results show several benefits of the new concept, especially higher thermal efficiency of the receiver, lower receiver temperature and lower parasitic losses. Due to these improvements the annual output could be increased by 27%, compared to the solar air heating system.     

Biofuels and the biorefinery concept

Liquid fuels can be made by refining a range of biomass materials, including oil-rich and sugar-rich crops such as oil-seed rape and sugar beet, biomass that consists mainly of plant cell walls (second generation lignocellulosics), macro- and micro-alga, or material that would now be discarded as waste. This can include animal bi-products as well as waste wood and other resources. In the medium-term, plant cell (lignocellulosic) material is likely to be favoured as the feedstock for biorefineries because of its availability. The UK may make use of a number of these options because of its complex agricultural landscape. There are now a range of targets for biofuel use in the UK, although their environmental effects are disputed.     

Damage informatics concept for plant life-cycle management

‘Damage informatics’ means here a total life-cycle management methodology including event scenario making, statistical damage analyses and risk-based maintenance decision-making. Event scenarios are expressed in terms of event trees for various components in steam turbines and gas turbines. The field damage data of specific machine types are analysed statistically and the probability of damage or failure can be expressed through the bivariate distribution function of total start-up cycles and operation time. For gas turbine nozzle cracking data, a damage evolution law for low cycle fatigue cracking is applied and the nozzle position dependence is clarified as the major cause of data dispersion. The risks are obtained by the product of probability and consequence of damage/failure and then shown to provide the basis of maintenance decision-making.     

A numerical support of leading point concept

Unsteady three-dimensional Direct Numerical Simulation (DNS) data obtained from 16 statistically planar and one-dimensional, complex-chemistry, lean (equivalence ratio is equal to 0.50 or 0.35) hydrogen-air flames propagating in forced, intense, small-scale turbulence (Karlovitz number up to 565) are reported. The data are analyzed to compare roles played by leading and trailing edges of a premixed turbulent flame brush in its propagation. The comparison is based on the following considerations: (i) positively (negatively) curved reaction zones predominate at the leading (trailing, respectively) edge of a premixed turbulent flame brush and (ii) preferential diffusion of molecular or atomic hydrogen results in increasing the local fuel consumption and heat release rates in positively or negatively, respectively, curved reaction zones. Therefore, turbulent burning velocities computed by deactivating differential diffusion effects for all species with the exception of either H₂ or H are compared for assessing roles played by leading and trailing edges of a premixed turbulent flame brush in its propagation. By analyzing the DNS data, a significant increase in the local fuel consumption and heat release rates due to preferential diffusion of H₂ or H is documented close to the leading or trailing, respectively, edges of the studied flame brushes. Nevertheless, turbulent burning velocities computed by activating preferential diffusion solely for H₂ are significantly higher than turbulent burning velocities computed by activating preferential diffusion solely for H. This result indicates an important role played by the leading edge in the propagation of the explored turbulent flame brushes.     

The concept of distribution flexible network PV system

In stand-alone photovoltaic (PV) systems, when the battery is fully charged, the excess generated power is wasted. To solve the problems of wasted excess power, a distributed flexible network photovoltaic (DFNPV) system is studied. It incorporates many PV subsystems each consisting of PV panel, DC/DC converter, and load, and are connected to each other with shared batteries. The excess generated power of the subsystem is transferred between PV subsystems to compensate the lack of power in other subsystems.The control method of transferring power is based on simple voltage control of the subsystems. The output voltage in a given subsystem decreases if a transient excessive load is larger than the generated power; as a result excess power is transferred from another subsystem that has sufficient power and higher voltage output. In this study, this proposed operation method is demonstrated by simulation of power transfer between two subsystems and among four subsystems. Furthermore, to estimate the size of the DFNPV system within an acceptable voltage drop, the relationships between cable length, power loss, and cable types are discussed.     

A new concept for an osmotic energy converter

A new concept for an osmosis power generation system is presented. While the power production of a conventional system is based on continuous, increasing volumetric flow of solution directed to a turbine, the new concept is based on the pressurizing of fluids by osmosis. Two different new concepts were studied. In the first case, the osmotic module consists of the osmotic membranes, fresh water and solution. In the second case, gas is included in the solution part of the module. Consequently, the new system without gas was found to result in more than 2.5 times higher power values than the conventional concept. Copyright © 2001 John Wiley & Sons, Ltd.     

The concept of a smart wind turbine system

A smart wind turbine concept with variable length blades and an innovative hybrid mechanical-electrical power conversion system was analyzed. The variable length blade concept uses the idea of extending the turbine blades when wind speeds fall below rated level, hence increasing the swept area, and thus maintaining a relatively high power output. It is shown for a typical site, that the annual energy output of such a wind turbine that could double its blade length, could be twice that of a corresponding turbine with fixed length blades. From a cost analysis, it is shown that the concept would be feasible if the cost of the rotor could be kept less than 4.3 times the cost of a standard rotor with fixed length blades. Given the variable length blade turbine system exhibits a more-or-less linear maximum power curve, as opposed to a non-linear curve for the standard turbine, an innovative hybrid mechanical-electrical power conversion system was proposed and tested proving the feasibility of the concept.     

The modular concept of the Oscillating Wave Surge Converter

In this study, we discuss the hydrodynamics of the modular concept of a well known wave energy device - the Oscillating Wave Surge Converter. Such a concept has emerged to address some of the shortcomings in the original design of the device. A mathematical model is presented to analyze the effect of the interactions of the system. The analysis is performed with a modular system comprising of six identical modules of total combined width 24 m, reminiscent of the Oscillating Wave Surge Converter - Oyster800 developed by Aquamarine Power. Various design strategies are explored. It is shown that such a closely packed system of modules results in multiple resonances which can potentially be exploited to capture more power. It is also observed that the modules lying at the center of the system capture more energy than those lying at the edges. An optimization of power take-off system shows that at lower wave periods it is possible to capture the levels of power similar to those of an equivalent size rigid flap while at higher periods, the modular system has the potential to capture more energy due to the occurrence of multiple resonances.     

Preventing hydrogen detonations in road tunnels hydrogen trap concept

During research of new possible sources of energy, hydrogen was identified as a very promising potential energy carrier. Because of its very good energy characteristics, it has received a lot of research attention while its safety features are the ones that were its drawback for potential use. Before it can be put in general use in transportation industry, there were safety problems identified as hazard which has to be further analysed. The main problem in the transport is the safe use of hydrogen in road tunnels where it should be safe in case of possible accidents where its release could end up in fire, deflagration and even detonation. In the article, concept of hydrogen trap on the ceiling is developed and described based on the available data and research results from which passive safety approach is suggested to be used in future designs of the road tunnels.     

New concept for soot removal from a syngas mixture

A new concept for soot removal from inside a syngas environment has been studied. Particulate emissions are retained in a soot trap downstream from a thermal partial oxidation (TPOX) reformer, while the syngas atmosphere itself is utilized as a gasification agent to achieve continuous and passive trap regeneration. This work analyses the performances of the loading and the regenerating phases of a wall flow soot trap in a syngas environment in an ad hoc developed test rig. A balance point between filtered and removed soot was actually reached at trap temperatures in the 800-1000 °C range with soot abatement efficiencies above 95 wt%. The particulate is obtained from a TPOX reactor operating in very rich fuel conditions, using methane as fuel. The final application of the reactor and trap assembly is a micro CHP system, based on an SOFC fed by a TPOX reformer. However, application to larger contexts (e.g. biomass gasification plants) can be envisaged.     

A new duplex Stirling engine concept for solar-powered cooling

The global cooling demand is one of the fastest growing energy demands and is putting a strain on the electricity infrastructure. Solar-powered cooling could provide most of the cooling demand due to the coincidence of the cooling demand and the solar irradiance. In particular, the solar-powered Stirling-cycle cooler has low maintenance requirement, high theoretical efficiency, and use of environmentally friendly gases. However, Stirling-cycle coolers are expensive due to high driving temperatures, complex heat exchangers, and expensive solar tracking so that they have so far only been successful at high-temperature difference applications. This study introduces a novel directly coupled solar Stirling cooler for which the hot engine cylinders are deployed inside evacuated tube collectors. The machine uses air as working fluid, and its driving mechanism is based on the free-piston, balanced compound technology that was patented by Finkelstein. A second-order mathematical model is used to investigate the performance of the machine for different cylinder arrangements, gas leakage rates, chilling temperatures, and solar irradiance. In addition, the regenerators are optimised to maximise the cold production. It is shown that mechanical frictions can be reduced to 20% by selecting an appropriate cylinder arrangement. The solar cooler achieves a maximum cold production rate of 367.5 W/m² without using external heat exchangers at load temperature of 7°C, which is comparable with photovoltaic powered coolers. In addition, the machine is relatively simple, has safe and quiet operation, uses ambient air as working gas, and is able to produce a wide range of chilling including sub-zero temperatures without changing the working gas. The direct thermal coupling of the Stirling cooler to evacuated tube collectors significantly reduces the complexity of the machine and removes intermediate heat transfer steps which reduce the performance. Thus, the suggested cooling technology has great potential for solar refrigeration, especially for low power and near ambient cooling.