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Abstract The solar thermoelectric generation（STEG）cogeneration system can provide heating and electric power simultaneously. Precedent studies on the STEG system were focused on getting higher electrical efficiency of the system and creating a new record. Optimization of thermal performance and evaluation of thermal efficiency are usually completed by calculation or numerical simulation. In this paper, a novel design of STEG cogeneration system was proposed. The system can work in three modes according to seasonal demand of hot water and electric power. A series of experiments were carried out in different working modes under variable conditions to evaluate the performance of the system. The results show that the system can generate 0.2 kW·h of electrical energy and about 100L of hot water at 41 °C in 1 day when solar irradiation is 1000 W/m2. The collector efficiency and electrical efficiency are calculated to be 42.2% and 2.1%, respectively. [ABSTRACT FROM AUTHOR]

Abstract Organic Rankine Cycle (ORC) is known as one of the best method amongst the other low-grade energy recovery methods. ORC can be applied for different applications such as geothermal, solar thermal and waste heat. However, the application of ORC in these applications requires the selection of suitable working fluid for better performance. So, this paper focuses on performance evaluation of ORCs for different working fluids. The modelling work was performed using MATLAB and, a thermo-physical database, REFPROP. The evaluation is performed based on the performance of the working fluid. The results reveal that MD2M & cyclopentane for temperature ranges 50 - 100 ⁰C, butane, neopentane & R245fa for 100 - 150 ⁰C, ethanol, methanol and propanone for 150-200 ⁰C and Water, m-Xylene and p-Xylene for 200 - 320 ⁰C are better working fluids for energy extraction. [ABSTRACT FROM AUTHOR]

Thermo Vapour Compressor TVC is the heart or prime mover of Multi-Effect Desalination MED system, it is also described as a steam ejector. Steam ejector is an economical device that utilizes high pressure steam to compress low pressure steam without any rotating parts or external power sources. The ejector performance is highly dependent on its geometry and operating conditions. The aim of the present work is to design and obtain steam ejector geometry, based on pre-specified operating conditions, and to investigate the flow behavior inside the ejector by using Computational Fluid Dynamics CFD through using “ANSYS FLUENT 14.5” software. In first section of this paper, 1-D mathematical model is carried out to predict the ejector geometry at designed operating conditions. The second part, describes the flow behavior inside the designed model of the ejector by CFD. CFD is a most reliable tool to reveal the phenomenon of the mixing process at different parts of the supersonic turbulent flow ejector and to study the effect of operating conditions on the effective ejector area. Obtaining such effects, using experimental work, is much costly and difficult. Finally, the results show the effect of the operating conditions on the entrainment ratio and the critical back pressure. [ABSTRACT FROM AUTHOR]

Thermo Vapour Compressor TVC is the heart or prime mover of Multi-Effect Desalination MED system, it is also described as a steam ejector. Steam ejector is an economical device that utilizes high pressure steam to compress low pressure steam without any rotating parts or external power sources. The ejector performance is highly dependent on its geometry and operating conditions. The aim of the present work is to design and obtain steam ejector geometry, based on pre-specified operating conditions, and to investigate the flow behavior inside the ejector by using Computational Fluid Dynamics CFD through using “ANSYS FLUENT 14.5” software. In first section of this paper, 1-D mathematical model is carried out to predict the ejector geometry at designed operating conditions. The second part, describes the flow behavior inside the designed model of the ejector by CFD. CFD is a most reliable tool to reveal the phenomenon of the mixing process at different parts of the supersonic turbulent flow ejector and to study the effect of operating conditions on the effective ejector area. Obtaining such effects, using experimental work, is much costly and difficult. Finally, the results show the effect of the operating conditions on the entrainment ratio and the critical back pressure. [ABSTRACT FROM AUTHOR]

Abstract: Energy efficient HVAC solutions may be obtained by combining different energy sources – fossil and renewable – into single hybrid systems. This leads to a variety of system concepts with specific boundary conditions. As a consequence, the definition of a unique representation method and a standardized performance evaluation procedure is a challenging task. Currently, two international projects promoted by the IEA are dealing with the representation and the performance calculation of a particular category of hybrid systems, i.e. integrated solar assisted systems. The HPP Annex 34 “Thermally Driven Heat Pumps for Heating and Cooling”, whose goal is to reduce the environmental impact of heating and cooling by the use of thermally driven heat pumps, has solar cooling as one of the systems under investigation. The joint project between SHC and HPP Task 44/Annex 38 “Solar and Heat Pump Systems” is focused on different system combinations of solar thermal collectors and heat pumps. The scope of the present paper is to show a systematic methodology to represent and evaluate the energy performance of complex hybrid systems. The proposed approach is a joint effort of the on-going IEA activities and will be discussed regarding the mentioned solar hybrid systems. However, the final goal of the work is to provide a basis for a simple, fair and transparent comparison of all systems for heating and cooling, regardless of the technology. [Copyright &y& Elsevier]

Abstract: Low emissivity coatings can significantly reduce radiative heat losses of glass panes for solar energy use. Their effectiveness is strongly dependent on their optical properties, which need to meet the requirements for the specific application. The paper analyses the performance of newly developed, highly transmitting and spectrally selective glass coatings based on transparent conductive oxides (TCO) for the use in flat plate collectors: Uncovered, single- glazed and double-glazed designs are taken into consideration. As functional layers both tin-doped indium oxide and aluminum-doped zinc oxide have been investigated. Collector efficiencies and annual collector yields are presented and compared to those of state-of-the-art collectors. Theoretical calculations are complemented by measurements on collector prototypes. The results show that a significant performance increase is accessible both in single-glazed collectors with low or non-selective absorbers and in double-glazed collectors with highly selective absorbers. [Copyright &y& Elsevier]

Abstract: The objective of Task 44 of the Solar Heating and Cooling program of the IEA is to assess performances and relevance of combined systems using solar thermal and heat pumps, to provide a common definition of performances of such systems, and to contribute to successful market penetration of these new promising combinations of renewable technologies. The Task is also Annex 38 of the Heat pump program and thus called T44A38. It gathers 12 countries and 55 participants.This paper presents the mid term results of the activity, which started in January 2010 and will last until December 2013. [Copyright &y& Elsevier]

Abstract: Large solar thermal systems (LSTS) are a promising market segment for solar energy. However, the realization of LSTS is more challenging compared to smaller plants, in both technical and economical terms. Permanent monitoring, data evaluation and fault detection during the operation of LSTS has shown by Fink et al. [3] and Peuser et al. [13] to be crucial for ensuring optimal performance. The only cost-effective way for permanent surveillance of LSTS operation is to make use of a computer-aided tool that performs as many steps as possible in an automated mode. The R&D project ‘IP-Solar’ developed the scientific basis and the technical fundamentals for such a system. This paper presents the current state of development emphasizing the methodology of the operation diagnostics. In particular, the algorithm-based approach, its implementation and testing are described in detail. [Copyright &y& Elsevier]

Abstract: Nowadays, European policies are promoting low energy buildings because of the high amount of energy consumption of the building sector. Phase change materials (PCM) have been studied in building implementation as a passive system to reduce the energy demand. Based in the experience obtained in the experimental set-up of Puigverd de Lleida (Spain), this paper pretends to analyze experimentally the PCM performance in a scenario with internal thermal gains. The experiments were done in three different cubicles with the same internal dimensions. The selection of the constructive systems used in these three cubicles allows the authors to evaluate the impact of using PCM in a typical Mediterranean building. A domestic heat pump for summer and an electric radiator for winter were installed to control the internal temperature of the cubicles. The results of summer period experiments show that the PCM cubicle stored the heat produced by the internal loads limiting the heat dissipation to the outer environment. Therefore, the energy consumed by the HVAC system of the PCM cubicle during the cooling period is higher than that of the other cubicles that dissipated the thermal loads according to the thermal resistance of their envelopes. Therefore, the PCM selection should take into account not only the comfort temperature but also the activity and functionality of the building. [Copyright &y& Elsevier]

Abstract: Previous research studies conducted on building components containing a phase-change material (PCM) have shown a great potential for direct and indirect energy and cost savings in the building envelopes. In particular, PCM impregnated gypsum boards, one of the most popular application of PCMs in buildings, have been reported to reduce building cooling loads by 7−20%. However, in order to best design and optimize the PCM-enhanced building materials, it is critical to accurately characterize the dynamic thermal properties such as enthalpy curve, volumetric heat capacity, sub-cooling, hysteresis − of these PCM-enhanced components. In addition, test data on these dynamic characteristics is necessary for whole-building simulations, energy analysis, and energy code work. In the past, the only existing readily-available method of thermal evaluation of PCMs utilized the Differential Scanning Calorimeter (DSC) methodology. Unfortunately, this method required small and relatively uniform test specimens. This requirement is unrealistic in the case of many PCM-enhanced building envelope products. Small specimens are not representative of PCM-based blends with gypsum, concretes, fiber insulations, plastic foams etc., since these materials are often not homogeneous. In this paper, dynamic thermal properties such of a ½” thick PCM impregnated gypsum board are analyzed based on a novel dynamic experimental procedure: using the conventional HFMA. The gypsum board tested in this work contained 20−25% by weight of a microencapsulated PCM with latent heat of ∼120kJ/kg. First, the theoretical details of the dynamic HFMA (DHFMA) are described. In essence, top and bottom plates of the HFMA are set to the same temperature and heat flow signals from the corresponding heat flux meters are integrated over time to compute the enthalpy changes during a temperature step change. Volumetric heat capacity profile is determined by taking the slope of the enthalpy curve. A negligible sub-cooling and hysteresis is observed for the PCM impregnated gypsum board. In addition, thermal properties such as onset of melting and solidification, and sensible heat of the specimen when PCM was in solid and liquid state were also determined. Dynamic properties such as heat capacity profiles and peaks of melting and solidification cycles, and amount of sub -cooling as measured by DHFMA were found to be relatively close to the DSC results on the same microencapsulated PCM. [Copyright &y& Elsevier]

Abstract: In this paper, the effect of material composition on the overheating protection performance of thermotropic systems with fixed domains (TSFD) is studied. Several thermotropic layers were formulated by variation of both, matrix material and thermotropic additive. Refractometry was applied in order to obtain refractive index data as a function of temperature of all material constituents and to screen wether material combinations are promising to formulate or not. Investigations concerning optical properties, switching temperature and switching process were carried out applying UV/Vis/NIR spectrometry. Morphological analysis was conducted with a Scanning Electron Microscope (SEM). Several TSFD showed reasonable light-shielding efficiency. Nevertheless further optimization of scattering domain size and shape is necessary to improve the light shielding performance. [Copyright &y& Elsevier]

Abstract: The availability of solar radiation in phase with the seasonal as well as hourly cooling load profiles in most of the office buildings in the Mediterranean region, in addition to the large share of primary energy consumed for air- conditioning applications in office buildings create a high motivation for the utilization of solar cooling technology for such type of buildings. A solar heating and cooling system for an office building in Italy has been designed, installed and monitored within the framework of the EC co-funded project SOLERA aiming at developing highly integrated solar thermal heating and cooling system that is able to achieve a high solar fraction both for the heating and cooling seasons. The analysis of the system performance during 2011 is presented in this paper, with main focus on electricity consumption during summer. The analysis has been carried out according to the monitoring procedure developed within the frame of the IEA SHC Task 38. [Copyright &y& Elsevier]

Abstract: In this paper the comparison between the performance of a cross flow heat exchanger in wet and dry operation for air handling process has been investigated. In addition, a case study of application of the component to perform indirect evaporative cooling in a AHU was studied with the software TRNSYS.Using experimental data and an appropriate analytical method, energy saving performances of the system has been evaluated through the entire cooling season for a typical Mediterranean site. Results show that high energy saving potential can be obtained if the component is operated in wet operation in term of reduction of electricity consumption. [Copyright &y& Elsevier]

Abstract: Energy requirements for new buildings show the strong direction given by UE Directives to improve energy performance in buildings according to economic feasibility. Nowadays it is possibile to const ruct new buildings reaching a substancial reduction in energy consumption containing prices and time for the construction. In architectural competitions are always included architectural, energy and economic parameters of quality which are decisive in the success of the project design. A Housing Contest to collect projects with high performance and low cost for residential buildings for the Municipality of Comune di Milano, Italy, and the future construtions in the local area was launched by the to involve architects and professionals on the future development of the urban landscape giving specific requirements to achieve high performance. These requirements were focused on energy quality, acoustic quality, quality of the building site, guaranteed time schedule, prefabrication, economic affordability in comparison with the market trend of costs. The project presented in the paper is one of the chosen building by the Municipality to represent a pilot project for possible future constructions. In the Contest all the design group were in team with a builder to verify and guarantee the costs of the construction. The high energy performance required coupled to the low cost assured by the projects gave the Municipality a good example of how is possible to fulfill quality levels recommended by EU Directives and national regulations. In the Contest a high energy performance for heating was compulsory. The project described in the following paragraphs not only fulfill this energy requirement but also is almost self-sufficiency since it provides the energy for heating, cooling and common electrical demand. [Copyright &y& Elsevier]

Abstract: This paper focuses on the analysis of the operation of a solar cool ing system based upon an adsorption chiller. The air-conditioned building studied is a laboratory located in a temperate climate region (Belgium). The monitoring reveals thermal and electrical coefficient of performance (COP) of the cooling system for different time scale (10s to1 month). The whole system including solar collectors, adsorption machine, recooling unit and hot storage is simulated. The models are then confronted to the measurements. Measurement period is shared between 2011 and 2012. Enhancements have been achieved during winter 2011 to have a more efficient system operation. The aim of this experimental work is to describe, for both measurement periods, the influence of operating conditions on the energy efficiency (thermal behavior and electrical consumption). On the simulation point of view, the main objective is to find accurate models for all the components. The adsorption chiller model is not yet precise enough to evaluate the performance of solar cooling in other conditions. [Copyright &y& Elsevier]

Abstract: Urban neighborhoods could represent an optimal scale for the implementation of innovative energy strategies. However, barriers at the economic, regulatory and administrative level are still present. In this framework, it is important to operate on three levels of the energy system: by reducing energy demand; by optimizing generation and management system, and by integrating local renewable energy sources. In recent years, as a result of an important agreement with the Italian Ministry of Environment, Lombardy Region has supported numerous measures for energy efficiency and renewable resources integration among its territory. The funding supported different actions such as improvements of the buildings envelope, substitution of old gas boilers for heat generation with more efficient components, integration of solar thermal systems in buildings, hydrogen and more sustainable mobility, and district heating plants, which present contribution concerns. About district heating the incentives were provided within two different calls: one aimed at the creation of plants and district heating networks and another for the extension of existing systems. Main aim of the research is to evaluate effects, effectiveness, pros and cons of the several calls for funding; to that end a methodology was developed in order to collect the data and elaborate representative energy, environmental and economic indicators. The most important characteristics, conditions and technical features of the considered plants are described in the present paper trying to provide information on the effectiveness of the supporting measures taken in order to orient future choices and to identify the most promising strategies and technologies for improving energy and environmental performances of communities. In particular present paper is related to 10 district heating plants: 6 are based on biomass and located in mountain areas, 3 are based on natural gas and located in urban areas, while the last is connected to the urban waste to energy plant. One of the important lesson is learned is that district heating (fuelled by biomass, fossil, waste and CHP or not) represents an innovative field of knowledge far from standard: in general each plant has to be evaluated on the basis of specify characteristics and it is very hard to find out average performances from the environmental and economic point of view. The results obtained during the monitoring campaign could help in providing information on the effectiveness of the supporting measures adopted and also to orient future choices by Lombardy Region and, in particular, to identify the most promising technologies for improving energy and environmental performances of communities and to develop a model for the optimization of energy use in the built environment. [Copyright &y& Elsevier]

Abstract: The Drake Landing Solar Community in Okotoks, Alberta, Canada utilizes a solar thermal system with borehole seasonal storage to supply space heating to 52 detached energy-efficient homes through a district heating network. Systems of similar size and configuration have been constructed in Europe, however, this is the first system of this type designed to supply more than 90% of the space heating with solar energy and the first operating in such a cold climate (5200 degree C-days). Solar heat captured in 2293 m2 of flat-plate collectors, mounted on the roofs of detached garages, is stored in soil underground and later when needed for space heating, is extracted and distributed through a district system to each home in the subdivision. Independent solar domestic hot water systems installed on every house are designed to supply more than 50% of the water heating load. Annual greenhouse gas emission reductions from energy efficiency improvements and solar energy supply exceed 5 tonnes per house. The seasonal storage utilizes approximately 34,000 m3 of earth and a grid of 144 boreholes with single u-tube heat exchangers. The system is configured to maintain the centre of the field at the highest temperature to maximize heating capacity and the outer edges at the lowest temperature to minimize losses. A short -term thermal storage consisting of 240 m3 of water is used to interconnect the collection, distribution and seasonal heat storage subsystems. The system has undergone detailed monitoring since it was brought into service in July 2007 to characterize its performance and to improve the TRNSYS model employed in its design. A solar fraction of 97% in its fifth year of operation, convincingly confirms the design target, a solar fraction of more than 90% in year five, has been met. This paper describes the system and its operation, presents 5 years of measured performance and compares those results against the TRNSYS predicted performance for the same period. [Copyright &y& Elsevier]

Abstract: This paper presents the analysis of the experimental tests performed with an absorption refrigeration advanced Solar-GAX system, designed for 10.5kW (3 Ton) of cooling using ammonia-water mixture. The system designed for operation at heat source temperatures of around 200°C, consists of an absorber and generator of a falling film type and air cooled finned tube condenser and absorber, being an option for areas with water scarcity. Heat source temperatures of 160°C were established to simulate the conditions of using solar thermal concentrating technology to supply heat the system, this means the system operating at partial load. Cooling capacities from 3 to 7kW were obtained, with an average coefficient of performance (COP) of 0.37. Thermal stability was rapidly reached, after only 15minutes of operation. [Copyright &y& Elsevier]

Abstract: The paper investigates experimentally the thermal performance of a ventilated double skin facade (DSF) with phase change material (PCM) in its air channel, during the heating season in the Mediterranean climate. Two identical house-like cubicles located in Puigverd de Lleida (Spain) were monitored during winter 2012, and in one of them, a ventilated facade with PCM was located in the south wall. The ventilated facade can operate under mechanical or natural ventilation mode and its thermal control depends on the weather conditions and the energetic demand of the building. The experimental results conclude that even though the use of the ventilated facade with PCM improves significantly the thermal behaviour of the whole building (working as a heat supplier in free floating tests, and reducing significantly the electrical consumption of the HVAC systems), these improvements might be increased if a thermal control is used. [Copyright &y& Elsevier]

Abstract: The European Union has set a goal that the energy use in the built environment shall be reduced by 41% to the year 2050 compared to 2005-2006. This could introduce new opportunities for solar thermal systems in cold countries. In such countries, like Sweden and Canada, the economy in solar thermal collector installation projects is often spoiled by the fact that most of heating energy demand of the building occurs during periods when the available solar energy is low. The present paper investigates the performance of solar thermal systems subjected to different quota between space heating and domestic hot water demand (DHW). This study investigates the performance of a solar thermal system integrated to four different buildings with varying heating loads in two different locations, Sweden and Canada. Models of single family houses are created which are able to simulate the total heating demand with different heating demand profiles but the same DHW demand. Simulations are performed in TRNSYS, an advanced tool used to simulate transient systems. Results indicate that solar combisystems tend to generate more useful energy and therefore be more cost effective when installed in buildings with higher heating demands. [Copyright &y& Elsevier]

Abstract: This paper is summarizing the results of a research carried out for assessing thermal performances of Trombe walls integrated in lightweight constructions. Phase-change materials, substituting heavy thermal storage mass, have been used in order to improve the energy performance of the system. For evaluating the device sensibility to external environmental conditions, five Australian cities (representative of five different climatic zones) have been considered. Furthermore, variations of PCM position in the external envelope and of melting point temperatures have been taken in account in order to define the most suitable technology for each climatic area. [Copyright &y& Elsevier]

Abstract: This paper presents an approach to measure, characterize and simulate photometric performances of light transmission efficiency of an innovative transparent concrete panel for façades. The transparency was obtained by a texture of PMMA resin insertions in the fiber reinforced concrete panel. In the first part of the paper integrating sphere measurements were collected to derive spectral optical properties of the panel. The optical properties of a specimen were measured for incidence angles between normal and 60° and the spectral results were reported. The data collected during the measures were used to: create and validate a simplified Radiance model of the panel and to optimize simulation parameters to estimate properly the total internal reflections effects thought the PMMA resin insertions. [Copyright &y& Elsevier]

Abstract: Impact of users on thermal behaviour of a building and a building''s impact on the use of different spaces are two aspects that are subject of post occupancy evaluation of the present paper. The building was designed according to passive concepts, including Insulated envelope and internal thermal mass; also computer simulations were used to optimize thermal performance of different components of the design. The evaluation was done by using quantitative method to document climate and interior lighting. A qualitative method was also used for analysis of building use and perception of indoor climate by users. High windows were placed in the hall and lobby for night flush to cool the building during summer. However, the difficulty of opening them had led that night ventilation was never practiced. In winter, less window''s areas would be sufficient to satisfy the thermal comfort during the day while ensuring a sufficient level of natural lighting. Daylight level measured in the morning shows that the level of illumination is acceptable; however it remains below the required minimum during the afternoon during fall, winter and spring. Small to medium windows, (4-10% of floor area) on west orientation could improve the daylight during the afternoon. Also, a late closing of the youth club would be desirable for the spring, summer and fall when days are long. The results of the interviews describe a high level of satisfaction from users with regard to indoor climate. Bioclimatic design has a positive impact on the use of the youth. [Copyright &y& Elsevier]

Abstract: The aim of this paper is to explore the concept of Solar Urban Planning with the goal of developing an operative methodology to achieve the best conditions towards Zero Energy Building (ZEB). In the last two centuries there has been a transformation in the form of cities, from being relatively compact to a confused urban sprawl. By 2020, all new buildings constructed in the European Union will have to be “nearly zero energy” in response to the Energy Performance of Building Directive. The ZEB goal is technically achievable but dependents on various conditions of the urban structure. By 2050, the population will grow from 7 to 9 billion, the facts are clear and the time to act is now. The task to provide high solar performances buildings could be attained in a better way if the urban planning process integrates a solar energy approach to both new and existing urban environments. A “new step” that determines the solar potential of an urban area, implements a model connected to the needs of buildings and their capacity to produce energy from solar resource integrating solar analysis with parametric urban design, represents a useful tool to be added into the conception phase of urban planning. The methodology has been applied to a case study in Portugal to plan the correct orientation and form of new buildings to guarantee the optimal efficiency of photovoltaic roof and façade systems and calculate their solar energy production. Considering the importance and the complexity to minimize the use of cooling system and reduce the buildings energy consumption, multiple actions are required. Solar urban design is a “new phase” of sustainable urban planning, a phase that has wide horizons of development and could provide new solutions to the worlds energy problem by reducing its consumption and improves the performance of future buildings. [Copyright &y& Elsevier]

Abstract: This paper presents a study of the effect of key design parameters on energy performance of two-storey single family dwellings and small scale neighborhoods, in a mid-latitude northern climate. Design parameters include the geometric shapes of dwelling units and their assemblage in a neighborhood. The effects of the design parameters are presented in a matrix that relates design parameters to performance criteria. An example for an evaluation system of the performance of design alternatives is proposed, based on design parameter effects and weights assigned to different performance criteria. Performance criteria considered are heating and cooling energy consumptions, solar energy generation, and shift of peak of electricity generation. The evaluation system is a decision-aiding tool, which enables selection of design parameter values leading to optimal performance for the assumed performance criteria. A design methodology is proposed for the design of solar optimized housing units and neighborhoods, based on the matrix of results and the evaluation system. [Copyright &y& Elsevier]

Abstract: The market for small Solar CombiSystems (SCSs) is penalized by its lack of common performance test method. The methodology proposed in this paper is based on the SCSPT procedure which tests each combisystem as a whole system on a semi-virtual test bench. Test results are used to identify a “Gray Box” model of the tested SCS, which includes an Artificial Neural Network. This model can then simulate the behavior of the system for any climate and any building. Results of all those simulations are finally used according to the FSC procedure in order to characterize the tested SCS performances with a simple curve. An experimental study of this methodology with two real SCS is presented in this paper. [Copyright &y& Elsevier]

Abstract: From 2009 to 2011, the Ministère des Ressources naturelles et de la Faune (MRNF), which is the ministry responsible for natural resources and wildlife in Quebec, supported a pilot project aiming to develop the solar domestic water heater (SDWH) market in Québec. Seventy participants took part in this program, of which 23 agreed to be part of a campaign for monitoring the energy performance of their solar system. The Laboratoire des technologies de l’énergie (LTE) of the Hydro-Québec Research Institute was commissioned by the MRNF to conduct the monitoring. The main results of the study are published in this paper. [Copyright &y& Elsevier]

Abstract: This paper introduces the overview of China''s solar water heater industry. The share of non-pressurized compact SWHs is about 80%. Due to its low pressure-resistant, the thermal performance testing for non-pressurized SWHs is not as easy as the pressurized system. The pressure for the supplied water for the testing must be lower enough to ensure the tested SWH cannot be damaged. So, except the method identified in ISO 9459-2, China national standard introduces another way to test the thermal performance for the non-pressurized SWHs. It uses a pump to mix the water in the non- pressurized water tank, records the temperature at the beginning and the end of the test, and calculates the heat gain under the daily irradiation. This test method is much closer to the real using situation for these SWHs. In 2012, China will issue a new national standard for solar water heaters Minimum allowable values of energy efficiency and energy efficiency grades for domestic solar water heating systems. This standard requires all products sold in China should be labeled with the energy efficiency grade. The energy efficiency grade is calculated with the value obtained by the thermal performance test. A complicated test system like a testing laboratory is not suitable for the factories in China. A compact automatic test facility to assist the factory to determine its products’ energy efficiency grade is needed. This test facility has user-friendly interface developed with LabView, can perform the test and print the test report automatically. [Copyright &y& Elsevier]

Abstract: Benchmark refrigerated systems in the road transportation sector are powered by diesel, having operation costs of up to 6,000 €/y. This paper presents the development of an alternative refrigeration system based on fuel cells, with higher efficiency, reduced costs and independent of diesel price fluctuations. Energy load profiles have been analyzed and the fuel cell stack and auxiliaries are being modeled in order to dimension and design a balance of plant and control algorithms that ensure a safe and easy utilization. Additionally, a prototype shall be tested under different load profiles to validate the control strategies and to characterize the performance of the system. [Copyright &y& Elsevier]

Abstract: This study was to investigate the CO2 reforming under isothermal condition. The fuel conversion efficiency and hydrogen-rich gas production were enhanced via the oxidative dry reforming (ODR) from simulated biogas (50%-CH4+50%-CO2). This paper covers two subjects. The first was to investigate the CO2 conversion characteristics under various feeding molar ratios (e.g. H2/CO2 and O2/CH4 molar ratio). In the second, the whole performance index of the reformer was investigated. The experimental results demonstrate that the CO2 reduction capacity of methane is superior to that of hydrogen. This effect is clearer under higher reaction temperatures. The ODR reaction experiment results indicate that adding appropriate amounts of oxidants can increases the methane conversion and reforming efficiency. But, the excessive oxidizes could be reduce the CO2 conversion efficiency. Additionally, at high DR/ODR reaction temperatures, reverse water-gas shifting (RWGS) side reactions become signification, which can reduce CO2 to CO efficiently, thereby improving the CO2 conversion efficiency. Overall, the optimal methane conversion efficiency can reach 100% in ODR reaction (O2/CH4 molar ratio=0.5). The CO2 conversion efficiency is based on DR reactions (CO2/CH4 molar ratio=1) reaching between 57% and 95%. [Copyright &y& Elsevier]

Abstract: Our commitment is the development of an industrial-grade Class AAA solar simulator based on LED technology . Presently, the LEDSim™ covers the full wavelength range of interest for Si-PV with an extension in the UV, matching AM1.5g from 350nm to 1100nm. To achieve user-defined target spectra we apply 22 different LED packages including several uncommon types. We present a measured spectrum tuned to AM1.5g. It follows from rare lifetime information for some LED species that we need to set a strong focus on reliability determination for our lightheads. In this paper we show how we confirm the lifetime promise of the LED technology with reliability testing. Modern design-for-reliability methods are taken into account in order to increase the reliability of the LEDSim™. Beam shaping and homogeneity are key functions of a sun simulator, and a large effort is made on achieving Class A homogeneity for each wavelength interval as specified in IEC 60904-9 . We are testing different kinds of LED optics and add mirror channels to achieve the best relation between homogeneity and intensity. [Copyright &y& Elsevier]

Abstract: The gain of Metal Wrap Through (MWT) cells and modules in comparison to standard modules has been extensively reported in the past. Most studies are limited to Standard Test Conditions (STC), and outdoor performance is not regarded. This paper studies the outdoor performance and energy yield of back contact foil based MWT modules in comparison to standard modules.A big advantage is the very low series resistance of the MWT modules; its influence on energy yield is simulated and compared to standard modules for different locations throughout Europe. It is shown that the gain at STC conditions is largely translated into a gain in the produced energy.The gain is confirmed by outdoor measurements on two locations in Europe. It is shown that the monthly performance ratios of the MWT and H-pattern modules do not differ and thus the gain at STC is a good measure for the eventual gain in energy yield. [Copyright &y& Elsevier]

Abstract: In the future, large offshore wind turbines are expected to reach a rating of 10 MW. To reduce the corresponding weight increase of the nacelle, research has started to focus on solutions to omit the step-up transformer in each turbine. Therefore this paper investigates a modular converter suitable for a special high power, transformer-less generator drive with 36 kV output DC-voltage. The drive consists of nine converter modules connected in series on the DC-side to obtain a high output voltage. Due to the series connection, extra care has to be taken to achieve equal voltage division between the converter modules. Therefore, a DC-voltage balancing scheme based on a droop control is proposed. The performance of the system will be demonstrated through simulations in EMTDC/PSCAD. [Copyright &y& Elsevier]

Abstract: The structural aspects of a 70 meter long blade in an upwind, horizontal-axis wind turbine were developed in this paper for use in a high wind speed location. A hybrid composite structure using glass and carbon fiber plies was created yielding a light-weight design with a low tip deflection. The blade was subjected to FEA studies to demonstrate its ability to withstand the extreme loading conditions as defined in the international offshore wind standard. The results confirmed the design to have acceptable performance with regard to tip deflection, maximum and minimum strains, and critical buckling load. Detailed descriptions of the structural components and ply layups are presented along with the resulting maximum and minimum strains and deflections. In addition, optimization techniques were introduced to provide insight for future studies with the blade. [Copyright &y& Elsevier]

Abstract: The feasibility of the application of a spar-type wind turbine at a moderate water depth is studied in this paper. In the oil and gas industries, spar-type offshore platforms are widely applied in deep water. The same idea is used in offshore wind technology to present the Hywind concept based on a catenary moored spar in deep water. The draft of the spar limits the application of spar-type wind turbines in shallow water. However, it is possible to design spar-type wind turbines for moderate water depths. The present article studies the feasibility and performance of such a design. A spar-type wind turbine at a moderate water depth called “ShortSpar” is introduced in the present article. A catenary moored spar-type support structure is applied as a base for the 5-MW NREL land-based turbine. The power performance, structural integrity and dynamic responses of a 5-MW catenary moored spar-type wind turbine in deep water (DeepSpar) have previously been studied. In the present article, the responses of the spar-type wind turbines, ShortSpar and DeepSpar, are compared. The HAWC2 code is used to carry out the coupled aero-hydro-servo-elastic analyses. Different environmental conditions are used to compare the responses. A dynamic link library (DLL) is used to feed the mooring forces at each time step into the HAWC2 code. The force-displacement relationships are obtained from the Simo-Riflex code. The comparison of the responses of ShortSpar and DeepSpar in different load cases indicates the feasibility of implementation of spar-type wind turbine in moderate water depths. The results show that the spar-type wind turbine at a moderate water depth exhibits good performance, and its responses are reasonable compared with those associated with a spar-type wind turbine in deep water. The total mass (the structural mass plus the ballast) of ShortSpar is 35% less than the mass of DeepSpar, while the statistical characteristics of the generated power are almost the same for both spars. This mass reduction for ShortSpar helps to achieve a more cost-effective solution for floating wind turbines at a moderate water depth. [Copyright &y& Elsevier]

Abstract: The potential of contact passivation for increasing cell performance is indicated by several results reported in the literature. However, scant characterization of the tunneling layers used for that purpose has been reported. In this paper, contact passivation is investigated by insertion of an ultra-thin AlOx layer between an n-type emitter and a Ti/Pd/Ag contact. By using a 1.5nm thick layer, an increase of the minority carrier lifetime by a factor of 2.7 is achieved. Since current-voltage measurements indicate that an ohmic behavior is conserved for AlOx layers as thick as 1.5nm, a 1.5nm AlOx layer is found to be a candidate of choice for contact passivation. [Copyright &y& Elsevier]

Abstract: Recently, various control models have been developed to optimize the performance of wave energy converters in order to enhance their long term economic value. Among others, the control of the all-electric Power Take Off (PTO) has been actively studied. This paper introduces the application of bio-inspired Ant Colony Optimization (ACO) metaheuristic as decision support for real-time wave energy extraction. It is found that the performance of the proposed algorithm is appealing as it is able to provide optimal parameter values to the control model within short interval. This provides fast-tuning capability to the PTO while sparing suffcient time for the WEC to respond to the continuously changing sea states. [Copyright &y& Elsevier]

Abstract: Linear Quadratic Gaussian (LQG) control methodology shows useful properties of good performance and robust-ness in controller design applied to wind turbine. Typically, in the design procedure LQG method is necessary to select weighting matrices in order to solve the Algebraic Riccati Equations and then get the matrices Kalman Filter gain and optimal state-feedback. In order to optimize a LQG control applied to Double-Fed Induction Generator in wind power system, a Genetic Algorithms (GA) adapted to get the best values of the element of weighting matrices is proposed in this paper. The performance indices ISE and ITSE are a good alternative to obtain the fitness function to design LQG controllers with GA. The simulation results show the high effectiveness of this optimal design method. [Copyright &y& Elsevier]

Abstract: In this paper, the ways of employing energy storage devices in hybrid powered orthoses have been discussed. Since these devices have many unrivalled advantages, they are environmentally safe, they store kinetic energy as potential energy and release it when it is needed and they do not need external power supply. In this paper an energy storage device (linear extension spring) has been implemented in FES-cycling, the efficiency has been calculated for different spring positions and different spring constants. It was clear that FES-cycling efficiency increases when the spring constant increases, then the pedal, spring and the overall powers were calculated, and it appears that by leaning the spring position the overall power will be always positive, and the spring absorbs the exceeded pedal energy and releases it when the pedal power is negative. This study highlights the importance of using energy storage devices to improve FES-cycling performance, which has been proven that such improvement is highly related to the mechanical design of the bicycle. [Copyright &y& Elsevier]

Abstract: This paper presents practical performance study of one axis mechanical tracking of PV grid connected system, which is designed, studied, and analyzed comparing with a fixed PV system at HIAST with capacity of 100 watts with tilt angle 35 degrees. This paper presents and compares the capital costs of tracking and fixed systems and the energy injected into the grid. [Copyright &y& Elsevier]

Abstract: The synthetic jets have been identified as a promising technique for various fields of both dynamic fluid and aerodynamics, by using different numerical simulations which recently have been played an important role in their development. In the aim to provide the flow mechanisms by influencing both their visualization and their theoretical analysis provided by the implementation of the different validation code, several passive and active techniques have been studied to explore particularly their characteristics. The present work investigates the performance of the Moving Boundary technique which is one of many different computational tools implemented to reproduce the flow behavior of a 3D synthetic jet. The experimental work is a well stabilized test case used as a CFD benchmark by the CFDVAL 2004 workshop. The main feature of the present work is in use of a moving boundary implemented by use of generating computational mesh at every time step of the unsteady computation. Results are first intended to calibrate versus the measurement in order to be sure that phases are accordance. Several points and lines positions are chosen to compare the averaged velocity components. The preliminary results are encouraging and allow reproducing at least qualitatively the flow behavior animations of the synthetic jet. Nevertheless further improvements have to be added, mainly in grid generation and probably in turbulence model selection. The results given in this paper will be used for validating perspective computational studies to control the boundary layer separation. [Copyright &y& Elsevier]

Abstract: Since its discovery, electrical energy represents one of the most decisive fields in any technology. In this paper, a comparative study between fixed hysteresis band current control (HBCC) and adaptive hysteresis band current control techniques in speed drive system is presented. These techniques control the variation of output voltage of the three phase rectifier. The theory and analysis of both the conventional fixed-HBCC and the adaptive HBCC which are the control techniques that operate at any condition with variable and constant switching frequency, are respectively developed. At the end, the performance of such control technique has been observed and discussed thanks to a simulation study carried with Matlab Simulink environnement. [Copyright &y& Elsevier]

Abstract: This paper shows that we can improve the performance of the auto-adjustable electric machines if a fractional dynamic is considered in the algorithm of the controlling order. This structure is particularly interested in the separate control of active and reactive power of the double-fed induction generator (DFIG) of wind power conversion chain. Fractional regulators are used in the regulation of chain of powers. Knowing that, usually, the source of DFIG is provided by converters through controlled rectifiers, all this system makes the currents of lines strongly polluted that can have a harmful effect for the connected loads and sensitive equipment nearby. The solution to remedy these problems is to replace the power of the rotor DFIG by a matrix converter which represents a THD less important. The structure of the adopted adjustment is tested using Matlab/Simulink and the results are presented and analyzed for a variable wind. [Copyright &y& Elsevier]

Abstract: The here presented applied research and development project is targeted to the development and application of new and improved techniques in plant design, performance analysis and process control. Hereto following the required steps are illustrated and the goals are outlined. The project covers the development of a previously patented anaerobic digestion process, adaption of flow cytometry as an analytical instrument and investigation of innovative ways of disposal of solid fermentation wastes. The preliminary experiences with a newly built research plant employing a novel anaerobic biogas digestion technique are discussed. In this paper the first outcomes concerning the construction and operation are discussed. A novel method of disposal of the fermentation wastes is also discussed and first results are shown. [Copyright &y& Elsevier]

Abstract: This paper presents the development of a novel solar-powered adsorption cooling tube. The tube consists of adsorbent bed (solar collector), condenser, and evaporator, all in one unit. Activated Carbon-Methanol is used as a working pair to suit cooling and refrigeration applications. From the experimental studies of the tube results all year round, performance and produced cooling are evaluated as well as recommendations and conclusions for best performance are presented [Copyright &y& Elsevier]

Abstract: The need for air-conditioning in the Mediterranean countries is higher and higher due to the effects of global warming. This paper deals with an investigation of a high performance, solar-driven air-conditioning system, the project entitled “Mediterranean AIRCOND”, is funded by the European Community under the „Community Activities in the Field of the specific program for RTD and demonstration on “Energy, Environment and Sustainable Development”. “AIRCOND” aims to study and investigate performances of advanced solar driven air conditioning system; the field system is composed of three sub systems: the heating loop, the ejector cycle and the cold storage-air handling units: The heating loop is composed of a solar array of 60 square meters evacuated tube solar collectors; installed at a tilt angle of 45o and facing to south, a 3000 L tank which is used as hot water storage in order to cover the required energy by the ejector cycle. The cold water produced by the ejector cycle will be then transferred in a 900L cold storage tank filled with 800L micro-encapsulated phase change material (MEPCM) for cold storage. It is designed to meet the dynamic cooling load. The ejector was tested at the School of the Built Environment in the University of Nottingham in UK and then transferred to Tunisia for field evaluation. Many previous theory studies have been fulfilled on this technology but never been performed experimentally at this level. This paper presents the research effort made and the experience gained during the implementation of the whole system: Different operation strategies were followed during more than one year to make the ejector cycle functional. The whole procedure has turned out to be very difficult; it was particularly difficult to obtain a deep vacuum and to ensure a good vacuum quality; this is a necessary working condition for the ejector cycle. Successful ejector tests were obtained during 8min, 15min and 40min, after many investigations; later experiments led to 3hours of continuous working. Results are very promising; the installation is still under tests in order to obtain a whole day permanent working of the ejector cycle and so of all the solar installation. [Copyright &y& Elsevier]

Abstract: A detailed mathematical simulation and experimental investigation of airflow in solar chimneys is studied in this paper. Several experimental studies were carried out on the solar chimney; their choice depends on the parameter of the design and the thermal performances for different geometrical configurations. The experimental tests show that the field speeds in the chimney is influenced by the width of the channel and also of the angle of inclination of the chimney. Therefore, investigations have been carried out in this paper to find the effect of inclination on the performance of solar chimney in Ouargla Province, Algeria. The simulation of this problem is implemented into the commercial CFD code Fluent 6.3. 26. The conservation equations of mass, continuity and energy are solved by the Finite Volume Method. The validation of the results is presented. An good agreement between the experimental results and simulation ones is observed. [Copyright &y& Elsevier]

Abstract: The hybrid controls are the controls combining several techniques. Their purpose is to benefit from performance of each of these techniques. The control proposed in this paper is based on this hybrid approach; combining the performances of the controls which are based on the tools of the artificial intelligence (artificial neural networks and fuzzy logic) applied to control the single-phase induction machine without capacitor supplied by voltage source inverter. The application of this approach to the single-phase induction machine is a contribution to the study of this machine. Indeed, this type of machine has not yet taken its whole share from various works present until now, compared to the three-phase induction machine. The simulation results show the feasibility and good performance obtained by the proposed control. [Copyright &y& Elsevier]

Abstract: Nowadays a way to optimize photovoltaic systems consists in implementing distributed structures, implying the use of electronic devices. In this paper we show performances of improved DC-DC converters able to feed an inverter. Resulting efficiency allow us to consider parallel HVDC architecture connecting independently PV modules with low section wiring. [Copyright &y& Elsevier]

Abstract: This paper analysis the cushion performance of the bucket unit for molded pulp material model, which based on the ANSYS software to simulate the compression test and study the effect variety of the draft angle and the height on the model. [Copyright &y& Elsevier]