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1 – 10 of over 2000
Article
Publication date: 12 June 2009

M.H. Saffaripour and M.A. Mehrabian

The purpose of this paper is to predict the global solar radiation intensity in areas where meteorological stations do not exist and information on solar radiation cannot be…

Abstract

Purpose

The purpose of this paper is to predict the global solar radiation intensity in areas where meteorological stations do not exist and information on solar radiation cannot be obtained experimentally.

Design/methodology/approach

The approach to achieve the objective of the paper is developing multiple regression relations between the global solar radiation intensity (the dependent variable) and geographical, geometrical, astronomical and meteorological parameters (the independent variables). The independent variables used for this purpose were selected based on their ease of measurability outside the meteorological station and without expensive equipment. The number of independent variables is arbitrarily chosen and directly affects the accuracy of predictions.

Findings

Linear regression relations using one, two, three, four, five, six, and seven independent variables were developed to predict the global solar radiation intensity on horizontal surfaces. An advanced computer program based on least square analysis was used to obtain the regression coefficients. The relations having the highest correlation coefficients were selected. The study shows even when only one independent variable (declination angle) is used, the one variable regression relation predicts the global solar radiation with an accuracy that is satisfactory in most engineering applications.

Originality/value

The diversity of regression relations introduced in this paper gives the engineer such a broad freedom of choice, that knowing only an astronomical parameter of the site makes him capable of estimating the global solar radiation intensity within acceptable margins. The predicted values of global solar radiation intensity by this approach can be used for the design and performance estimation in solar applications. The statistical model developed in this research was validated when compared with the measured data in Yazd airport. The measured data used to analyze the model equations were collected in a 13‐year period. No investigation of this type exists having such degree of accuracy in geographical, geometrical, astronomical and meteorological parameters in Iran.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 19 no. 6
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 3 October 2016

Lurwan Mahmoud Sabo, Norman Mariun, Hashim Hizam, Mohd Amran Mohd Radzi and Azmi Zakaria

The purpose of this study is to evaluate the reliability of the technique for estimating solar radiation in areas of rough topography and to detect the source of error and means…

Abstract

Purpose

The purpose of this study is to evaluate the reliability of the technique for estimating solar radiation in areas of rough topography and to detect the source of error and means for improvement.

Design/methodology/approach

Spatial data of the study area in the form of digital elevation model (DEM) coupled with geographic information system (GIS) were used to estimate the monthly solar radiation at locations with rough topography. The generated data were compared with measured data collected from all the selected locations using NASA data.

Findings

The results show that the variation in topographic parameters has a strong influence on the amount of solar radiation received by two close locations. However, the method performed well for solar radiation estimated in the areas of rough topography.

Research limitations/implications

The proposed approach overestimates the monthly solar radiation as compared with NASA data due to the impact of topographic parameters accounted for by the model which are not accounted by conventional methods of measurements. This approach can be improved by incorporating the reflected component of radiation in the model used to estimate the solar radiation implemented in the GIS.

Originality/value

The approach of using GIS with DEM to estimate solar radiation enables to identify the spatial variability in solar radiation between two closest locations due to the influence of topographic parameters, and this will assist in proper energy planning and decision making for optimal areas of solar photovoltaic installation.

Details

World Journal of Engineering, vol. 13 no. 5
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 3 May 2016

Amos Madhlopa

The purpose of this paper is to investigate a wall-integrated solar chimney for passive ventilation of a building cavity. Ventilation is required to improve the circulation of air…

Abstract

Purpose

The purpose of this paper is to investigate a wall-integrated solar chimney for passive ventilation of a building cavity. Ventilation is required to improve the circulation of air in the built environment. This can be achieved through natural or forced convection. Natural circulation can be driven by renewable energy, and so it promotes sustainable exploitation of energy resources. Solar energy is one of the promising renewable energy resources.

Design/methodology/approach

The chimney was designed to face the Equator on the wall of a room which required ventilation. Mean monthly daily heating and cooling loads of the room were computed with and without a solar chimney by using hourly meteorological data from nine different weather sites at low, medium and high latitudes. The chimney was implemented with and without airflow control, and simulated by using the ESP-r software.

Findings

Results show that the solar chimney with airflow control marginally reduced the heating load in the building envelope, with a similar effect being exhibited by the chimney with uncontrolled airflow. The cooling load was reduced by the controlled airflow at all the nine sites. In contrast, the uncontrolled airflow increased the cooling load at some sites. In addition, the chimney with airflow control reduced the annual total thermal load at all the sites, while the chimney with uncontrolled airflow raised the total thermal load at some locations.

Originality/value

The performance of solar chimneys designed with and without airflow control systems has been investigated under the same prevailing meteorological conditions at a given site. Findings show that controlling airflow in a solar chimney reduces the total thermal load in the built environment. This information can be applied in different parts of the world.

Details

Journal of Engineering, Design and Technology, vol. 14 no. 2
Type: Research Article
ISSN: 1726-0531

Keywords

Article
Publication date: 12 April 2022

Yingsi Wu, Kai Yang Thum, Hui Ting Yong, Aleksander Gora, Alfred Iing Yoong Tok and Vitali Lipik

Personal thermal management in functional textiles is in increasing demand for health care, outdoor activity and energy saving. Thus, developing new strategies is highly desired…

Abstract

Purpose

Personal thermal management in functional textiles is in increasing demand for health care, outdoor activity and energy saving. Thus, developing new strategies is highly desired for radiative cooling and/or heating by manipulation of the transmissivity, reflectivity and absorptivity of the textiles within solar energy and human body heat radiation ranges.

Design/methodology/approach

Inorganic additives including TiO2, Fe2O3, carbon black (CB), graphene and mica were incorporated into polymer films. The inorganic additives' full spectrum properties and thermal responses were comprehensively investigated.

Findings

The CB composite film showed the highest absorptivity over the full solar to human body radiation spectrum. The mica-white (mica-w) (mica coated with TiO2) and mica-red (mica-r) (mica coated with Fe2O3) composites showed the lowest solar energy absorptivity and a strong body heat radiation reflectivity. Furthermore, according to composites' thermal responses to the simulated solar and human body radiations, CB and mica are promising for both cooling and heating when applied in dual-functional thermal management textiles.

Research limitations/implications

Research has limitation related the amount of additives which can be added to textile. When powder is added to polyester yarn, the amount is limited by 2–3%. When powder is added to the composite which is used for printing, the amount of powder is limited by 5%.

Practical implications

A lot of apparel, especially sport apparel, contains prints. Decoration is one part of print application. Now, a lot of companies work under development of different additives, which provide additional properties to apparel. The closest targets for powder added to prints are cooling and heat retention. Quite often, inorganic additives possess dual properties: the inorganic additives may be heat reflective which his needed for heat retention, but may have high-thermal conductivity, which works well for cooling. Human body has complicated mechanism of heat exchange: convection, radiation and moisture evaporations play main role. The same additive may be cooling if there is a contact with skin but may be heating (IR reflective) if placed in the second or third layer. Thus, effect is needed to be studied first before real application.

Originality/value

This work could provide a comprehensive guideline for the rational design and application of thermal management composite textile materials by revealing the full solar to human body radiation performance of a series of inorganic materials.

Details

International Journal of Clothing Science and Technology, vol. 34 no. 4
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 1 May 2019

Shoaib Khanmohammadi, Mohammad Zanjani and Farzad Veysi

Present research focus on using solar energy as a renewable option for office buildings in different climatic conditions in Iran. To seeking a way to use clean solar energy and…

Abstract

Purpose

Present research focus on using solar energy as a renewable option for office buildings in different climatic conditions in Iran. To seeking a way to use clean solar energy and reduce current expense in buildings an investigation carried out. Nine office buildings in various climatic regions selected as case studies. Through a precise examination, buildings specifications, energy demand and climate information carried out. In the first step based on the buildings type and hot water demand, solar water heater systems designed for each case. In the second step, a cost-benefit analysis is done to detriment the economic aspects of implement aforementioned type of solar system. A cost-benefit analysis is done from saving energy and return time of investment point of view. Results indicate that solar water heater with low investment about US$500 and payback time between 2 and 5 years can be noticed as a desirable renewable option in case studies. Furthermore, analysis reveals that thermal load of building is more effective on fuel saving in building, while solar radiation intensity has more effective on the payback in solar water heater utilization.

Design/methodology/approach

In this study based on thermal load of nine building office and radiation of different part of Kermnashah province, the possibility of solar water system is investigated.

Findings

Analyses reveal that the thermal load of building is more effective on fuel saving, while solar radiation intensity has more effective on the payback in solar water heater utilization. The main originality goes back to consideration of different meteorological conditions in solar water heater selection.

Details

World Journal of Engineering, vol. 16 no. 2
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 13 June 2016

Kada Bouchouicha, Abdelhak Razagui, Nour El Islam Bachari and Nouar Aoun

This paper aims to propose an approach based on physical model integration for surface and cloud albedo computation using an approximate form of the atmospheric radiative transfer…

Abstract

Purpose

This paper aims to propose an approach based on physical model integration for surface and cloud albedo computation using an approximate form of the atmospheric radiative transfer equation and sun-pixel-satellite.

Design/methodology/approach

The data used in this study are global irradiance collected from for various sites in Algeria, and data were obtained from the processing of the high-resolution visible images taken by the Meteosat Second Generation satellite in 2010.

Findings

The results suggest that the standard deviation obtained with this method is similar to that obtained with current estimation methods. The hourly and daily correlation coefficients range between 0.95 and 0.97 and between 0.97 and 0.99, respectively. The hourly and daily mean bias errors range between −0.2 and +1.2 per cent and between −0.2 and +1.4 per cent, respectively. The hourly and daily root mean square errors range between 10 and 17 per cent and between 4 and 8 per cent, respectively.

Originality/value

This paper developed a new estimating method that derives the hourly global horizontal solar irradiation at a ground level from geostationary satellite data under local climate conditions.

Details

World Journal of Engineering, vol. 13 no. 3
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 3 April 2018

Ahmed Ayadi, Haythem Nasraoui, Zied Driss, Abdallah Bouabidi and Mohamed Salah Abid

The purpose of this paper is to study a solar thermal system. Solar chimney power plants (SCPPs) produce electrical energy and thermal heat from solar radiation. The thermal study…

Abstract

Purpose

The purpose of this paper is to study a solar thermal system. Solar chimney power plants (SCPPs) produce electrical energy and thermal heat from solar radiation. The thermal study of SCPPs is required, as these solar systems are characterized by high costs.

Design/methodology/approach

This study presents a numerical study of unsteady airflow characteristics inside an SCPP. In fact, the generated power of the SCPP depends on environmental conditions. To validate this study, a solar prototype is built in the National School of Engineers of Sfax, University of Sfax, Tunisia, North Africa. The system is mainly composed by a collector, an absorber, a chimney and a turbine. The collector diameter is 2750 mm, the collector roof height is 50 mm, the chimney height is 3,000 mm and the turbine diameter is 150 mm.

Findings

The local characteristics of the air flow are presented and analyzed, such as the distribution of the temperature, the magnitude velocity and the total pressure. Analysis confirms that ambient air temperature and solar radiation are important environmental variables for the improvement of solar chimney efficiency.

Originality/value

Although much work has been done to date, it has been noted that the most published works have presented the profiles of air velocity and air temperature in a specific position within the solar setup. However, these profiles could sometimes be misinterpreted. In fact, some researchers did not focus on the distribution of air temperature, air velocity and pressure. These parameters are important to optimize the solar system. Indeed, the most published works deal with a larger prototype, such as the Manzanares prototype. However, it has not found connections between larger and small prototypes of SCPP.

Details

Journal of Engineering, Design and Technology, vol. 16 no. 2
Type: Research Article
ISSN: 1726-0531

Keywords

Article
Publication date: 14 January 2020

Nedjma Abdelhafidi, Nour El Islam Bachari, Zohra Abdelhafidi, Ali Cheknane, Abdelmotaleb Mokhnache and Loranzo Castro

Integrated solar combined cycle (ISCC) using parabolic trough collector (PTC) technology is a new power plant that has been installed in few countries to benefit from the use of…

Abstract

Purpose

Integrated solar combined cycle (ISCC) using parabolic trough collector (PTC) technology is a new power plant that has been installed in few countries to benefit from the use of hybrid solar-gas systems. The purpose of this paper is to investigate the challenges in modeling the thermal output of the hybrid solar-gas power plant and to analyze the factors that influence them.

Design/methodology/approach

To validate the proposal, a study was conducted on a test stand in situ and based on the statistical analysis of meteorological data of the year 2017. Such data have been brought from Abener hybrid solar-gas central of Hassi R’mel and used as an input of our model.

Findings

The proposal made by the authors has been simulated using MATLAB environment. The simulation results show that the net solar electricity reaches 18 per cent in June, 15 per cent in March and September, while it cannot exceed 8 per cent in December. Moreover, it shows that the power plant responses sensibly to solar energy, where the electricity output increases accordingly to the solar radiation increase. This increase in efficiency results in better economic utilization of the solar PTC equipment in such kind of hybrid solar-gas power plant.

Practical implications

The obtained results would be expected to provide the possibility for designing other power plants in Algeria when such conditions are met (high DNI, low wind speed, water and natural-gas availability).

Originality/value

This paper presents a new model able to predict the thermal solar energy and the net solar-electricity efficiency of such kind solar hybrid power plant.

Article
Publication date: 3 October 2016

Fahim Ullah, Min Kang, Lubna Hassan, Ninghui Li, Jun Yang, Xingsheng Wang and Mansoor Khan Khattak

The purpose of the study was to develop a performance flat-plate solar collector that would be used as a solar drier for fruit fig (Ficus carica L). This study proposes how and…

Abstract

Purpose

The purpose of the study was to develop a performance flat-plate solar collector that would be used as a solar drier for fruit fig (Ficus carica L). This study proposes how and why solar energy is important for drying the agricultural products. This study aims to expand the domain of solar collector for different purposes and, most important, for agricultural resource normally found in the literature.

Design/methodology/approach

The paper opted for an exploratory study using the flat-plate solar collector with drying chamber for drying purposes of agricultural products. During the experiment, the data were collected with moisture content, drying rate of the product and solar irradiation falls on the collector.

Findings

This paper describes that how flat-plate collector works for agricultural products and how to reduce the moisture content in the product (fig). Efficiency of collector was evaluated under the ambient temperatures of 24°C. Efficiency also significantly increased from 53 to 55 per cent with an increase in ambient temperature from 22 to 24 °C. Figs (Ficus carica L) were dried in the drying chamber of the flat-plate solar collector. The products were dried at temperature of 55-65°C and 15 to 20 per cent humidity.

Research limitations/implications

Because of this research chosen, the research results are beneficiary for agricultural users for drying purposes. Therefore, the researchers are encouraged to dry the agricultural product with flat-plate solar collector, because it reduced the moisture content of the product very fast.

Originality/value

This paper fulfills an identified need to study that how flat-plat solar collector can be used.

Details

World Journal of Engineering, vol. 13 no. 5
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 11 September 2019

Ceyda Aksoy Tırmıkçı and Cenk Yavuz

The purpose of this paper is to propose a fixed PV energy system design and a sun tracking PV energy system design to meet the primitive energy demands of a typical house in…

Abstract

Purpose

The purpose of this paper is to propose a fixed PV energy system design and a sun tracking PV energy system design to meet the primitive energy demands of a typical house in Sakarya, Turkey with energy payback times (EPBT) and greenhouse payback times (GPBT) calculations.

Design/methodology/approach

The designs were developed based on the total solar radiation received on the surface of the PV modules. The EPBT and the GPBT of the designs were investigated by utilizing the current embodied energy data of the literature and annual energy output of the proposed systems. The monthly mean total solar radiation, the yearly total solar radiation and the annual energy output of the systems were calculated according to the results of previous studies of authors on 80-W prototypes of a fixed PV energy system tilted at the yearly optimum tilt angle of Sakarya and a two-axis sun tracking PV energy system.

Findings

The annual energy outputs of the fixed system and the tracking system were established to be 10.092 and 10.311 MJ, respectively. EPBT of the systems were estimated 15.347 years for the fixed system and 11.932 years for the tracking systems which were less than the lifespan of PV modules. The greenhouse gas emitted to produce and install the systems were estimated to be 6,899.342 kg for the fixed system and 5,040.097 kg for the tracking system. GPBT of the systems were calculated to be 5.203 and 2.658 years, respectively.

Originality/value

PV energy is clean without greenhouse gas emission during the operation. However, significant emissions occur in the life cycle of PV modules until the installation is completed. Therefore reducing the number of PV modules make great differences in the GPBT of PV energy systems. In this paper, comparisons between the GPBT results of the optimally tilted fixed system and tracking system were performed to discuss the best option by means of environmental concerns.

Details

Smart and Sustainable Built Environment, vol. 8 no. 5
Type: Research Article
ISSN: 2046-6099

Keywords

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