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Manama, Bahrain

Radhi H.,Global Engineering Bureau | Fikry F.,United Arab Emirates University | Sharples S.,University of Liverpool
Landscape and Urban Planning

The recent process of urbanisation in the Gulf Cooperation Council Countries (GCCC), including Bahrain, can increase ambient and surface temperatures in newly developed built up areas - the urban heat island (UHI) effect. This study investigates urban expansion in Bahrain over the last few decades and assesses its impact on atmospheric urban heat islands using remote sensing, advanced statistics of weather data and geographical information system (GIS). The study examines how the thermal behaviour of new urban areas is affected by urban elements, with two district models being considered. Numerical modelling is used to assess wind flow, temperatures and heat distribution fluxes within the two models. The assessment shows that mean air temperatures increase within the range of 2. °C-5. °C. The magnitude of the UHI is mainly reinforced by urban activity such as on-going construction processes, shrinkage of green areas and sea reclamation. A comparison of results between the two studied districts reveals that the mean temperature is increased by 2. °C-3. °C in new artificial islands, and by 3. °C-5. °C in deserted urban lands with hot arid conditions. The distribution of urban radiant heat islands is varied and depends largely on the type of land cover and urban surface. Urban grids and structure have a significant impact on the thermal behaviour of newly developed built up areas. Human comfort is improved in the presence of water bodies and green areas. © 2013 Elsevier B.V. Source

Sharples S.,University of Liverpool | Radhi H.,Global Engineering Bureau
Renewable Energy

This paper assesses the technical and economic performance of PV technology integrated into residential buildings in the Gulf Cooperation Council (GCC) countries. It highlights the value of PV electricity for the GCC society from the perspective of consumers, utilities and environment. Through a systematic modelling analysis it is shown that the efficiency of PV system drops by 4-6% due to high range of module temperature and also a change in power output due to high ambient temperatures. Consequently, the outputs of horizontal and vertical PV modules are found to be less than estimates based on standard test conditions. Economically, this study shows that building integrated photovoltaic (BIPV) systems are not viable in GCC countries and cannot compete with conventional electricity sources on a unit cost basis. From a society point of view, however, the integration of PV technology into buildings would have several benefits for the GCC countries, including: first, savings in capital cost due to central power plants and transmission and distribution processes; second, an increase in the exported oil and natural gas used for electricity generation; and third, a reduction in the CO2 emissions from conventional power plants. When these considerations are taken into account then BIPV should become a feasible technology in GCC countries. © 2012 Elsevier Ltd. Source

Radhi H.,Global Engineering Bureau | Sharples S.,University of Liverpool
Applied Energy

Authoritative reports show that building electricity consumption can increase steadily once temperature values within urban regions exceed their rural values. This study first assesses the role of higher temperatures in the variation of Bahrain's domestic electricity consumption for air-conditioning, using the cooling degree days (CDD) as a quantitative index. It then examines how this consumption is affected by urban features. The assessment is performed using established scenarios of the urban heat island (UHI), advanced statistics of building stock and data for electricity consumption. Simple regression equations are developed to predict the effects of temperature alterations on the electricity consumption. This work shows that the variation in CDD is a direct result of modifications to the urban microclimate. The annual total urban CDD value is up to 17% higher than the rural CDD value. A sharp increase of up to 10% in electricity consumption for air-conditioning occurs in urban regions from April to October. Estimates of the electricity demand for dense urban centres that are based on air temperature values measured in open areas, such as airports, can cause an error of almost 6%. The developed statistical equations can be a valuable and convenient method of quantifying the domestic electricity consumption for air-conditioning in Bahrain and other Gulf countries. © 2013 Elsevier Ltd. Source

Radhi H.,Global Engineering Bureau | Sharples S.,University of Liverpool | Fikiry F.,United Arab Emirates University
Energy and Buildings

The objective of this work is to assess the impact of climate interactive facade systems (CRFS) on cooling energy in fully glazed buildings. This work integrates building energy simulation and computational fluid dynamics to establish boundary conditions and to develop geometrical models based on a new constructed multi-storey building. It performs 3D steady RANS CFD simulations, covering the CRFS, outdoor conditions and indoor environment. The result shows that the application of CRFS reduces solar gain into internal spaces, but increases the temperature within the system cavity. From a cooling energy standpoint, this study demonstrates that the CRFS is a construction solution that provides substantial savings for multi-storey glazed buildings in the hot arid climate of the UAE. On a typical summer day, between 17% and 20% of the energy required to cool the interior spaces can be saved. This range varies from orientation to another and depending largely on the level of irradiance and angle of incidence. The parameters that impact the most on cooling load are floor level related to screen height, followed by glazing properties and cavity depth in descending order. The outcome of this work offers to the building industry, a reliable indicator of the energy impact of climate interactive facade systems. © 2012 Elsevier B.V. All rights reserved. Source

Radhi H.,Global Engineering Bureau | Sharples S.,University of Liverpool
Environmental Impact Assessment Review

On a global scale, the Gulf Corporation Council Countries (GCCC), including Bahrain, are amongst the top countries in terms of carbon dioxide emissions per capita. Building authority in Bahrain has set a target of 40% reduction of electricity consumption and associated CO 2 emissions to be achieved by using facade parameters. This work evaluates how the life cycle CO 2 emissions of buildings are affected by facade parameters. The main focus is placed on direct and indirect CO 2 emissions from three contributors, namely, chemical reactions during production processes (Pco 2), embodied energy (Eco 2) and operational energy (OPco 2). By means of the life cycle assessment (LCA) methodology, it has been possible to show that the greatest environmental impact occurs during the operational phase (80-90%). However, embodied CO 2 emissions are an important factor that needs to be brought into the systems used for appraisal of projects, and hence into the design decisions made in developing projects. The assessment shows that masonry blocks are responsible for 70-90% of the total CO 2 emissions of facade construction, mainly due to their physical characteristics. The highest Pco 2 emissions factors are those of window elements, particularly aluminium frames. However, their contribution of CO 2 emissions depends largely on the number and size of windows. Each square metre of glazing is able to increase the total CO 2 emissions by almost 30% when compared with the same areas of opaque walls. The use of autoclaved aerated concrete (AAC) walls reduces the total life cycle CO 2 emissions by almost 5.2% when compared with ordinary walls, while the use of thermal insulation with concrete wall reduces CO 2 emissions by 1.2%. The outcome of this work offers to the building industry a reliable indicator of the environmental impact of residential facade parameters. © 2012 Elsevier Inc. Source

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