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1 – 9 of 9Ali Mostafaeipour, Hossein Goudarzi, Ahmad Sedaghat, Mehdi Jahangiri, Hengameh Hadian, Mostafa Rezaei, Amir-Mohammad Golmohammadi and Parniyan Karimi
In hot and dry climates, air conditioning accounts for a large portion of total energy consumption; therefore, this paper aims to investigate the impact of sol-air temperature and…
Abstract
Purpose
In hot and dry climates, air conditioning accounts for a large portion of total energy consumption; therefore, this paper aims to investigate the impact of sol-air temperature and ground temperature on the loss of cooling energy in hot and dry regions of Iran.
Design/methodology/approach
In line with this objective, the values of sol-air temperature along different directions and ground temperature at different depths were assessed with respect to climatic data of Yazd City. The impact of sol-air temperature and ground temperature on the rate of heat loss was investigated. So, energy loss of the walls aligned to four primary directions was calculated. This process was repeated for a 36 m2 building with three different shape factors. All analyses were conducted for the period from May to September, during which buildings need to be cooled by air conditioners.
Findings
Numerical analyses conducted for hot and dry climate show that sol-air temperature leads to a 41-17 per cent increase in the wall’s energy loss compared with ambient temperature. Meanwhile, building the wall below the surface leads to a significant reduction in energy loss. For example, building the wall 400 cm below the surface leads to about 74.8-79.2 per cent energy saving compared with above ground design. The results also show that increasing the direct contact between soil and building envelope decreases the energy loss, so energy loss of a building that is built 400 cm below the surface is 53.7-55.3 per cent lower than that of a building built above the surface.
Originality/value
The impact of sol-air temperature and ground temperature on the cooling energy loss of a building in hot and dry climate was investigated. Numerical analysis shows that solar radiation increases heat loss from building envelope. Soil temperature fluctuations decrease with depth. Heat loss from building envelope in an underground building is lower than that from building envelope in a building built above the ground. Three different shape factors showed that sol-air temperature has the maximum impact on square-shaped plan and minimal impact on buildings with east-west orientation.
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S. Marie Moghadasi, Albert J. de Wit and Fabio Chiacchio
The purpose of this paper is to determine thermal behaviour of wing fuel tank wall via heating by external heat sources.
Abstract
Purpose
The purpose of this paper is to determine thermal behaviour of wing fuel tank wall via heating by external heat sources.
Design/methodology/approach
A 3D finite element model of the structure has been created that takes into account convection, conduction and radiation effects. In addition, a 3D finite volume model of the air inside the leading edge is created. Through a computational fluid dynamics approach, the flow of air and thermal behaviour of the air is modelled. The structure and fluid model are coupled via a co-simulation engine to exchange heat flux and temperature. Different ventilation cases of the leading edge and their impact on the thermal behaviour of the tank wall (corresponding to the front spar) are investigated.
Findings
Results of 3D analysis illustrate good insight into the thermal behaviour of the tank wall. Furthermore, if regions exist in the leading edge that differs significantly from the overall thermal picture of the leading edge, these are visible in a 3D analysis. Finally, the models can be used to support a flammability analysis assessment.
Practical implications
Provided that the bleed pipe is located far enough from the spar and covered with sufficient thermal heat isolation, the composite leading edge structure will not reach extremely high temperatures.
Originality/value
These detailed simulations provide accurate results which can be used as reliable input for the fuel tank flammability analysis.
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Bifa Chen, Meiyan Zhang and Guo-an Tang
The rest-to-rest movements for a spacecraft, such as attitude adjustment and orbital manoeuver, are likely to excite residual vibration of flexible appendages, which may affect…
Abstract
Purpose
The rest-to-rest movements for a spacecraft, such as attitude adjustment and orbital manoeuver, are likely to excite residual vibration of flexible appendages, which may affect the attitude accuracy and even result in severe structural damage. The purpose of this paper is to present an approach to attenuating the vibration of flexible solar array by using reaction flywheel.
Design/methodology/approach
The reaction flywheel installed on solar array served as an actuator to provide reaction torque to a structure according to a designed feedback control law. This torque can be considered as an artificial damping. Experiment on a scale model of the solar array is first performed to verify the effectiveness of this method. Numerical simulation on finite element model of a full-scale solar array is subsequently carried out to confirm the validity of this method for practical engineering application.
Findings
The vibration suppression effect on the structure using a reaction flywheel is deduced by theoretical analysis. Results from both experiment and numerical simulation reveal that the efficiency of vibration attenuation is promoted.
Research limitations/implications
Improvements on control law are left for further study. Additionally, only the first-order bending vibration of the flexible solar array is attenuated, and further study is required for other types of vibration suppression.
Practical implications
An effective method is proposed for spacecraft designers to actively suppress the vibration of the flexible solar array.
Originality/value
A novel active vibration reduction scheme is proposed using a reaction flywheel to suppress vibration of the flexible solar array. This paper fulfils a source of theoretical analysis and experimental studies for vibration reduction measure design and provides practical help for the spacecraft designers.
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Hiroshi Yoshino, Kenichi Hasegawa and Shin‐ichi Matsumoto
Purpose – The purpose of this paper is to investigate the cooling effect of these features. Japanese traditional buildings have many features, which are effective for cooling the…
Abstract
Purpose – The purpose of this paper is to investigate the cooling effect of these features. Japanese traditional buildings have many features, which are effective for cooling the interior of the building. Design/methodology/approach – This paper first of all describes the characteristics of indoor thermal environment and the cooling effect of four traditional buildings, located in the Miyagi Prefecture in the northern area in Japan. The investigated buildings include traditional farmhouses and renovated farmhouses for the improvement of indoor thermal environment. Second, the cooling effect of traditional technologies was studied by the means of computer simulation using a model house, which takes the multi‐zone effects of heat transfer and air flow distribution into consideration. Findings – The paper finds that the cooling technologies of traditional buildings, such as solar shading by thatched roof decreases indoor temperature. The computer simulation revealed that natural ventilation, solar shading by thatched roof and the thermal mass by earthen floor are effective for interior cooling. Practical implications – This paper reveals the cooling effect of traditional technologies quantitatively. From the points of view of energy saving and environment symbiosis based on the understanding of physical principle, it is important to apply these traditional technologies to modern buildings. Originality/value – From the viewpoint of solution of global environmental problems, we can learn a lot from these vernacular technologies inherited from the past. This paper provides valuable information about building based on environmental design methodologies, which promote awareness about sustainable construction.
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A general numerical method for finding the steady state solution of a cyclic system is presented. The method determines the initial values by enforcing the conditions of…
Abstract
A general numerical method for finding the steady state solution of a cyclic system is presented. The method determines the initial values by enforcing the conditions of periodicity. In this way the initial value is found by integrating through only one cycle, often resulting in a considerable saving of computing effort. The method is applicable to any linear discrete set of difference equations with periodic parameters and forcing functions. The application of the method to a single pole representation of heat flow in buildings is demonstrated.
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Ioannis Spanos, Martin Simons and Kenneth L. Holmes
Implementation of the concept of passive solar heating design in dwellings has the potential to reduce energy consumption and reduce carbon emissions at little or no cost to the…
Abstract
Purpose
Implementation of the concept of passive solar heating design in dwellings has the potential to reduce energy consumption and reduce carbon emissions at little or no cost to the developer but with real benefit to the occupier. The aim of this paper is to investigate the possible benefits to be gained by the application of passive solar heating concepts to the orientation and fenestration of domestic buildings.
Design/methodology/approach
The approach used has been to select a simple domestic building designed to current building regulations and apply to it modifications which embody the principles of passive solar heating design. The anticipated performance of the modified building has then been compared with that of its counterpart of conventional configuration by application of a number of currently available simulation models. This study forms part of the Department of Trade and Industry sponsored Knowledge Transfer Partnership between Coventry University and Kenneth Holmes Associates, Chartered Architects.
Findings
It is predicted that by careful selection of orientation of a domestic building and modification of its layout, in order that glazing is strategically located, it is possible to effect significant improvements in energy consumption. There is some variation in the output of the alternative techniques but they present a common overall result.
Research implications/limitations
The solutions are purely predictive and it would be of great value if the outcomes could be evaluated by medium term measurement of the performance of dwellings constructed to the proposed design principles.
Practical implications
The concept under analysis could, at little or no cost, result in reduced energy demand in domestic buildings. In the current environmental climate, even modest improvements should be of considerable interest to designers and developers.
Originality/value
Draws upon alternative approaches to passive solar heating design in dwellings and reaches conclusions based on the application of these different approaches to a real live case study.
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Mostafa Rezaei, Ali Mostafaeipour, Niloofar Jafari, Nafiseh Naghdi-Khozani and Ali Moftakharzadeh
Acute shortage of potable water and energy supplies is expected to raise in developing countries in the near future. One solid way to address these issues is to exploit renewable…
Abstract
Purpose
Acute shortage of potable water and energy supplies is expected to raise in developing countries in the near future. One solid way to address these issues is to exploit renewable energy resources efficiently. Hence, this study aims to investigate wind and solar energy use in the coastal areas of southern Iran for renewable-powered seawater desalination and hydrogen production systems.
Design/methodology/approach
To accomplish the aforementioned purpose, five areas most prone to the problems in Iran, namely, Mahshahr, Jask and Chabahar ports and Kish and Hormoz islands were scrutinized. To ascertain the amount of wind and solar energy available in the areas, Weibull distribution function, Angstrom–Prescott equation and HOMER software were used.
Findings
The findings indicated that wind energy density in Kish was 2,014.86 (kWh/m2.yr) and solar energy density in Jask equaled to 2,255.7 (kWh/m2.yr) which possessed the best conditions among the areas under study. Moreover, three commercial wind turbines and three photovoltaic systems were examined for supplying energy needed by the water desalination and hydrogen production systems. The results showed that application of wind turbines with rated power of 660, 750 and 900 kWh in Kish could result in desalting 934,145, 1,263,339 and 2,000,450 (m3/yr) of seawater or producing 14,719, 20,896 and 31,521 (kg/yr) of hydrogen, respectively. Additionally, use of photovoltaic systems with efficiency of %14.4, %17.01 and %21.16 in Jask could desalinate 287, 444 and 464 (m3/yr) of seawater or generate 4.5, 7 and 7.3 (kg/yr) of hydrogen, respectively.
Originality/value
Compared to the huge extent of water shortage and environmental pollution, there has not been conducted enough studies to obtain broader view regarding use of renewable energies to solve these issues in Iran. Therefore, this study tries to close this gap and to give other developing nations the idea of water desalination and hydrogen production via renewable energies.
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Ali Mostafaeipour, Mojtaba Qolipour, Mostafa Rezaei and Hossein Goudarzi
This paper aims to investigate the techno-economic feasibility of wind power potential for a tribal region located in Gachsaran in the South-West of Iran.
Abstract
Purpose
This paper aims to investigate the techno-economic feasibility of wind power potential for a tribal region located in Gachsaran in the South-West of Iran.
Design/methodology/approach
Techno-economic feasibility study and analysis of data were conducted by HOMER v2.68 software. Simulations and calculations were performed for 10 kW turbines, 8 Trojan L16P batteries, 12 kW converter and 12 kW generator. To anticipate the pay back period (PBP) or the time required to reach profitability, an engineering economic method named net equivalent uniform annual was applied.
Findings
The power plant construction cost, including the initial cost, installing, replacing and project operating costs for useful life of 20 years was equal to $40970. The net income of the project for each year was $8538 and the calculations were carried out using interest rate of 18%. Results indicated that PBP was 13 years which is lower than 20 years useful life of the turbine. Therefore, it is economically feasible to use this type of turbine for the nominated region.
Originality/value
There has not been conducted a research regarding remote areas in Iran; therefore, this study aims at closing this research gap. Moreover, this method could be used for any remote areas in any other developing country.
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Esin Hasgül, İnci Olgun and Erhan Karakoç
The purpose of this paper is to emphasize passive energy refurbishment of vernacular building heritages and propose new application principles of sustainability from these…
Abstract
Purpose
The purpose of this paper is to emphasize passive energy refurbishment of vernacular building heritages and propose new application principles of sustainability from these vernacular heritages into contemporary architecture.
Design/methodology/approach
This paper is based on a research project (The Creation of a Prototype Project within the Application of Traditional Methods in Kastamonu, Küre Rural Settlements, 2017), through which vernacular architecture examples were analyzed, projecting for future interpretations for rural environments. Defining vernacular rural design principles is centrally important for the purposes of this project. As a case study from the Black Sea Region in Turkey, this example is investigated, and the outcomes of the analysis are used to reproduce in contemporary architectural terms the energy efficiency and rural patterns of the flexible rural house experience.
Findings
The research provides design principles for developing a new living experience in rural environments. The overall planning and architectural analysis are made in five neighborhoods in Küre, and three of unique vernacular architecture examples are chosen according to several criteria defined in “Kastamonu-Küre Ersizlerdere Village Design Guideline Project, 2014” to get the optimum data. Materials, orientation, form, spatial organization and building's indoor-outdoor relationship were analyzed by Autodesk's “Ecotect Analysis” simulation program.
Practical implications
Results of the proposed design principles of rural housing will be useful for new housing interpretations related to better rural development.
Originality/value
While defining energy efficiency criteria of vernacular itself, the results of this paper suggest new local solutions to ecological building design and engage with critical regionalism principles referring to the potentials of what traditional dwellings can teach contemporary design.
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