International Journal of Solar Energy最新文献

{"title":"Effects of cyclic operation on the characteristics of a microencapsulated PCM storage material","authors":"M. S. Uddin, H. Zhu, M. Hawlader","doi":"10.1080/0142591031000092210","DOIUrl":"https://doi.org/10.1080/0142591031000092210","url":null,"abstract":"Microencapsulated paraffin, a novel solar storage material, was prepared by simple coacervation technique and its performance characteristics, when subjected to cyclic operation, were evaluated in terms of structure and particle profile using SEM and FTIR, and the energy storage and release capacity expressed by DSC. The microencapsulated paraffin has shown large energy storage and release capacity (56∼58 J/g) during its phase change, and maintains its energy storage and release capacity, chemical characteristics and structural profile even after one thousand thermal recycles.","PeriodicalId":162029,"journal":{"name":"International Journal of Solar Energy","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125155939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of site dependent effects on the assessment of the radiative cooling potential","authors":"P. García, D. Luis","doi":"10.1080/01425910212849","DOIUrl":"https://doi.org/10.1080/01425910212849","url":null,"abstract":"The assessment the radiative cooling potential requires the knowledge of some site dependent boundary conditions affecting to the performance of the respective technological systems. These boundary conditions are mainly related to the existence of certain climatological solicitations that will determine the feasibility or not for each application. This paper presents a contribution to a more accurate assessment of the radiative cooling potential based on the analysis of the influence in the estimation of effective sky temperature and effective sky temperature depression of local or transient effects associated to the existence of a non standard vertical atmospheric structure. These eventual deviations are usually not considered in the conventional estimation models, based exclusively on surface information, and the suitability of the proposed approach is established by comparison with measured data.","PeriodicalId":162029,"journal":{"name":"International Journal of Solar Energy","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134488366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modelling solar half-hour data using fourth order cumulants","authors":"S. Safi, A. Zéroual, M. M. Hassani","doi":"10.1080/01425910214357","DOIUrl":"https://doi.org/10.1080/01425910214357","url":null,"abstract":"In this investigation we have two objectives. In the first one, we have developed a new simple and efficient technique to identify the parameters of the moving average (MA) process using the technique of higher order cumulants. The simulation for different orders of MA in the presence of Gaussian noise, for SNR lower than 20 v dB, gives satisfactory results. In the second objective, the proposed method was adopted for modelling half-hour solar radiation recorded in Marrakesh. Accurate design and optimisation of short response time solar energy systems with storage are sensitive to the stationary and sequential characteristics of half-hourly solar radiation. So, in order to benefit from some characteristics of stationary processes, a preliminary transformation was performed on the original data. The proposed method was used to look for a simple and efficient model to represent solar half-hourly radiation sequences needed for many applications in the solar energy field. The Giannakis technique based on cumulant diagonal slices and the partial autocorrelation function of Box & Jenkins and Brockwell & Davis are used for selection of the model order.","PeriodicalId":162029,"journal":{"name":"International Journal of Solar Energy","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124993417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spectral attenuation pathway length","authors":"Abiel Derizans","doi":"10.1080/01425910214356","DOIUrl":"https://doi.org/10.1080/01425910214356","url":null,"abstract":"The fundamental link between experimental and theoretical research is complementarity. The importance of attenuation models resides in the fact that most locations will not be able to measure their own spectral solar outputs. Attenuation models based on a dynamic database produced from a number of climate profiles, on the contrary, can fit all those climates and almost any other. No attenuation coefficient can dispense with a pathway length estimated using the most accurate methodology available. The author proposes a purely geometric calculation of the pathway length of a monochromatic bundle of collimated rays from the periphery of the atmosphere to the Earth's surface, through layers of different density having different attenuation coefficients. A simplification is offered to the user, who may choose to consider a homogeneous atmosphere with a single layer. The method is supposed to be accurate for any zenith angle. The author expects feedback.","PeriodicalId":162029,"journal":{"name":"International Journal of Solar Energy","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129429730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The early design model for prediction of energy and cost performance of building design options","authors":"Y. Yohanis, Brian Norton","doi":"10.1080/01425910214355","DOIUrl":"https://doi.org/10.1080/01425910214355","url":null,"abstract":"In order to encourage the use of computer modelling in building environmental analysis, it is necessary to provide a model developed from the designer's point of view. Detailed simulation models require a high degree of expertise and familiarity, further, there is also a need for detailed information not available in the early stages of the design process. Simplified models play an important role in the early stages of a design to achieve an integrated design: firstly, they are easy to use and, secondly, they require information easily available at the start of a design. In the Early Design Model (EDM) the solar gain utilisation factor has been determined as a continuous function of thermal mass. The differences between the annual energy predictions of EDM and SERI-RES ranges from 0.1% to 4.6% for time constants ranging from 378 to 2.52 hours. The differences between the two sets of predictions on monthly basis ranges from m 3.6% to m 6.48% (EDM's predictions being larger) during the heating season, and from +2.86% to a maximum of +51% (EDM's predictions being smaller) in the remaining part of the year. In addition to energy predictions, EDM incorporates a facility which gives cost indications.","PeriodicalId":162029,"journal":{"name":"International Journal of Solar Energy","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116837155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effusivity model for multi-layer walls","authors":"S. Hassid","doi":"10.1080/01425910212850","DOIUrl":"https://doi.org/10.1080/01425910212850","url":null,"abstract":"The effusivity model for describing the time response of walls to changes in heat flux is extended to two-layer walls using an integral method. Based on a simple integral method, shown to obtain results close to the ones of the effusivity method for the one-layer case, a simple correction of the expressions for temperature variation due to a step change in the heat flux is obtained. The results are shown to be in good agreement with the exact solution. It is shown that, depending on the ratio of the effusivities of the two layers, significant deviations from the results obtained using the effusivity of the outer layer can be expected.","PeriodicalId":162029,"journal":{"name":"International Journal of Solar Energy","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113954571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intelligent soft-computing based modelling of naturally ventilated buildings","authors":"G. Virk, D. Azzi, A. Gegov, B. Haynes, K. I. Alkadhimi","doi":"10.1080/0142591031000091112","DOIUrl":"https://doi.org/10.1080/0142591031000091112","url":null,"abstract":"The paper presents recent results on the application of the soft computing methodology for modelling of the internal climate in office buildings. More specifically, a part of a recently completed naturally ventilated building is considered which comprises three neighbouring offices and one corridor within the Portland Building at the University of Portsmouth. The approach adopted uses fuzzy logic for modelling, neural networks for adaptation and genetic algorithms for optimisation of the fuzzy model. The fuzzy models are of the Takagi-Sugeno type and are built by subtractive clustering. As a result of the latter, the initial values of the antecedent non-linear membership functions and the consequent linear algebraic equations parameters are determined. A method of extensive search of fuzzy model structures is presented which fully explores the dynamics of the plant. The model parameters are further adjusted by a back-propagation training neural network and a real-valued genetic algorithm in order to obtain a better fit to the measured data. Results with real data are presented for two types of models, namely Regression Delay and Proportional Difference. These models are applied for predicting internal air temperatures.","PeriodicalId":162029,"journal":{"name":"International Journal of Solar Energy","volume":"398 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122995314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multimedia education program for an active solar hot water system","authors":"P. Axaopoulos, Georgios Pitsilis, P. Panagakis","doi":"10.1080/01425910214358","DOIUrl":"https://doi.org/10.1080/01425910214358","url":null,"abstract":"An interactive multimedia education program has been developed to study the transient behaviour of an active solar heating system for domestic hot water production. The users can explore various cases, study what happens under different operating scenarios and examine the effects of altering conditions. In addition, simulation processes are used when a more quantitative understanding of the related subjects is needed, as they offer higher perceptual fidelity ( i.e. , more accurate representation of the situation being modelled). The simulation accounts for a large number of parameters and can be used to investigate their effects on the thermal efficiency of the solar collector and the system. It can also be used for an extensive set of exercises in the tertiary education sector. The operating principles and performance aspects of the different components have been considered providing a basis for understanding the components interaction and total system performance. The program is a user friendly, fast, easy-to-use and a powerful educational tool.","PeriodicalId":162029,"journal":{"name":"International Journal of Solar Energy","volume":"323 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131998586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of wind speed at the top of the tower on the performance and energy generated from _thermosyphon solar turbine","authors":"A. A. El-Haroun","doi":"10.1080/01425910212851","DOIUrl":"https://doi.org/10.1080/01425910212851","url":null,"abstract":"Energy generated from wind turbine depends to a great extent on the wind speed at its inlet. The use of thermosyphon solar tower is an attempt to increase the air velocity at inlet of the wind turbine and of course to increase its power. The wind speed in a certain location changes always with time and with the height above ground surface. In this work, the effect of wind speed at the top of the tower on the performance as well as on the energy generated from thermosyphon solar turbine was studied theoretically. One location in Egypt was chosen for this study. The calculations were achieved mainly with the solar turbine located at tower bottom. For the purpose of comparison, the energy generated from the solar turbine was compared with that generated from free wind turbine at tower height with the absence of solar tower. It was found that, the wind speed at the top of the tower results in a pressure drop which affects the performance of the thermosyphon solar turbine. This pressure drop increases with the rise in wind speed and will be zero only when the wind speed at the top of the tower reaches zero. It was found also that, there is an increase in friction losses through the tower and a decrease in both temperature difference between inlet and outlet of the tower and in heat losses from tower walls with the rise in wind speed in location. The inlet air velocity to the solar turbine and consequently its specific power were found to be increased with the increase in wind speed at the top of the tower. Therefore, the effect of wind speed at the top of the tower must be taken into account during thermosyphon solar tower calculations. By comparing the performance of solar turbine and the free wind turbine located at tower height with the absence of thermosyphon solar tower, it was found that the mean inlet air velocity to the solar turbine located at tower bottom and consequently its specific power are higher than these values for free wind turbine. The mean inlet air velocity to the solar turbine is found to be 117% of its value for a free wind turbine. The yearly specific energy generated from solar turbine is expected to be 157% of its value for free wind turbine.","PeriodicalId":162029,"journal":{"name":"International Journal of Solar Energy","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116433338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A new model for PV modules angular losses under field conditions","authors":"N. Martín, J. M. Ruíz","doi":"10.1080/01425910212852","DOIUrl":"https://doi.org/10.1080/01425910212852","url":null,"abstract":"Motivated by the significance of optical losses in many photovoltaic (PV) applications, and by the lack of useful tools that allow easy angular performance calculations, this paper presents a new analytical model for reflection losses in PV modules. It is based on the theoretical analysis of the optical characteristics of different commercial PV modules and results in good agreement with the experimental data in all cases. With this new useful tool, optical losses of PV modules under field conditions can be now easily quantified, as it is shown with an example. A strong dependence of optical losses on PV module tilt angle has been obtained, which has special significance in such applications as PV integration in buildings.","PeriodicalId":162029,"journal":{"name":"International Journal of Solar Energy","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114774912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}