Dubai, United Arab Emirates

Heriot - Watt University Dubai
Dubai, United Arab Emirates

Heriot-Watt University Dubai is a branch campus of Heriot-Watt University based in Dubai, United Arab Emirates. Established in 2005, it was the first campus of an overseas university to open in Dubai International Academic City. Wikipedia.

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Adeloye A.J.,Heriot - Watt University | Rustum R.,Heriot - Watt University Dubai
Hydrology Research | Year: 2012

Water resources assessment activities in inadequately gauged basins are often significantly constrained due to the insufficiency or total lack of hydro-meteorological data, resulting in huge uncertainties and ineffectual performance of water management schemes. In this study, a new methodology of rainfall-runoff modelling using the powerful clustering capability of the self-organising map (SOM), unsupervised artificial neural networks, is proposed as a viable approach for harnessing the multivariate correlation between the typically long record rainfall and short record runoff in such basins. The methodology was applied to the inadequately gauged Osun basin in southwest Nigeria for the sole purpose of extending the available runoff records and, through that, reducing water resources planning uncertainty associated with the use of short runoff data records. The extended runoff records were then analysed to determine possible abstractions from the main river source at different exceedance probabilities. This study demonstrates the successful use of emerging tools to overcome practical problems in sparsely gauged basins. © 2012 IWA Publishing.

Soori P.K.,Heriot - Watt University Dubai | Vishwas M.,Lead Systems Specialist
Energy and Buildings | Year: 2013

Lighting is the highest consumer of electrical energy in office buildings and it is one of the areas that offer many opportunities for improving the energy efficiency thereby reducing the energy consumption. This paper presents control strategy for energy efficient office lighting system design. The energy efficiency of a typical office building lighting system in Dubai is examined in this paper. The impact of use of natural lighting and artificial lighting on the HVAC system is assessed and highlighted. Lighting control algorithm is developed with the ultimate goal of achieving energy efficiency and health aspects of occupants into consideration. It is simulated using control systems simulation software functional explorer (FX) tools and recommendations are forwarded. The proposed control algorithm can be used as a reference to other new buildings to be built in Dubai or Middle East in general. © 2013 Elsevier B.V. All rights reserved.

Rohani G.,Heriot - Watt University Dubai | Nour M.,Heriot - Watt University Dubai
Energy | Year: 2014

The aim of this study is to model and design a hybrid renewable energy system for the remote area in Ras Musherib located in the western region of Abu Dhabi. The hybrid system, which consists of photovoltaic (PV) array, wind turbines, batteries and diesel generators, is designed to meet three known electric loads, 500kW, 1MW, and 5MW to be able to fulfill the primary load for 250, 500 and 2500 households. Different combination of wind turbines, PV, batteries and generators were evaluated in order to determine the optimal combination of the hybrid system based on the lower Net Present Cost method. The proposed hybrid system is modeled, optimized and simulated using Hybrid Optimization Model for Electric Renewable (HOMER). The obtained results show that the hybrid system with 15% of photovoltaic and 30% of wind turbine penetration found to be the optimal system for 500kW average load with initial cost of $;4,040,000 and total net present cost of $;14,504,952 over 25 years. The reduction in CO2 emission achieved in this study for the 500kW optimal hybrid system is 37% compared to the conventional diesel generator only power system. © 2013 Elsevier Ltd.

Chaudhry H.N.,Heriot - Watt University Dubai | Hughes B.R.,University of Leeds
Applied Energy | Year: 2014

A detailed investigation into determining the passive airside cooling capability of heat pipes in response to gradually varying external temperatures was carried out. The city of Doha, Qatar was taken as the location of case-study and the climatic data for June 21st, 2012 was incorporated in the transient thermal modelling. The physical domain comprised of 19 cylindrical heat pipes arranged in a staggered grid subjected to varying source temperatures. Wind tunnel testing was carried out for the duration of 24. h in order to establish a relationship between the source temperatures and their effect on the climate responsive behaviour of heat pipes. Infrared thermal imaging was used to capture the surface temperature formations at regular intervals of time during the test. The findings from the study showed that under a low Reynolds Number airstream, the cooling capacity of heat pipes increases by 0.1. °C for every 1. °C rise in external source temperature. Conversely, the investigation showed that the thermal response of heat pipes reduces by 0.3. °C when subjected to decreasing source temperature gradients of 1. °C, thus indicating a low effectiveness. The highest temperature reduction was recorded at 2.3. °C indicating a convective heat transfer of 1546. W and a heat pipe effectiveness of 8.5%. The test confirmed that in general, the heat pipes performed better during the day-time when external temperatures reached over 40. °C in comparison to night-time operation when external temperatures dropped below 35. °C. The present work successfully characterised the sustainable operation of heat pipes in reducing air temperatures without the requirement of any mechanical intervention. © 2014 Elsevier Ltd.

Chaudhry H.N.,Heriot - Watt University Dubai
Applied Thermal Engineering | Year: 2016

The way in which heat pipes are arranged plays an important role on the overall effectiveness of this sustainable thermal system. A numerical and experimental analysis into determining the optimum heat pipe streamwise distance for providing passive airside cooling in ventilation airstreams was carried out. The airflow and temperature profiles were numerically predicted using Computational Fluid Dynamics (CFD), the findings of which were quantitatively validated using wind tunnel experimentation. Using the heat pipe diameter (D) of 20 mm, the spanwise thicknesses were varied from 44 mm (St/D ratio of 2.2) to 52 mm (St/D ratio of 2.6). In order to ensure sustainable operation of the system, water was used as the heat pipe working fluid. Keeping the boundary conditions constant for all modes (inlet velocity of 2.3 m/s and inlet temperature of 314K), the rate of heat transfer was found to be directly proportional to the temperature difference between inlet and outlet interface. The findings determined that the spanwise thickness of 50 mm (St/D ratio of 2.5) provided the highest heat transfer in comparison to the other analysed models at 768 W. The overall effectiveness of the system was found to decrease from 5.6% to 4.7% when the spanwise thickness reduced from 50 mm to 44 mm. A good agreement was obtained between the numerical and experimental findings with a maximum error of 1.6% for temperature and 14.6% for velocity parameters. The investigation successfully evaluated the performance of heat pipes under varying geometrical arrangement, when utilised for the purpose of pre-cooling ventilation airstreams for a sustainable built environment. © 2015 Elsevier Ltd. All rights reserved.

Chaudhry H.N.,Heriot - Watt University Dubai | Hughes B.R.,Heriot - Watt University Dubai | Ghani S.A.,Qatar University
Renewable and Sustainable Energy Reviews | Year: 2012

Advancements into the computational studies have increased the development of heat pipe arrangements, displaying multiphase flow regimes and highlighting the broad scope of the respective technology for utilization in passive and active applications. The purpose of this review is to evaluate current heat pipe systems for heat recovery and renewable applications utility. Basic features and limitations are outlined and theoretical comparisons are drawn with respect to the operating temperature profiles for the reviewed industrial systems. Working fluids are compared on the basis of the figure of merit for the range of temperatures. The review established that standard tubular heat pipe systems present the largest operating temperature range in comparison to other systems and therefore offer viable potential for optimization and integration into renewable energy systems. © 2012 Elsevier Ltd. All rights reserved.

Ghaith F.A.,Heriot - Watt University Dubai | Abusitta R.,Heriot - Watt University Dubai
Energy and Buildings | Year: 2014

This paper addresses the viability of using the integrated Solar Heating Cooling (SHC) systems in residential buildings in UAE, by studying the thermal performance and potential energy savings, in addition to the economical and environmental aspects such as payback period and reduction in CO2 emissions. This work involves integration of the absorption chiller with solar thermal collectors to provide a continuous cooling. In the absence of sun, the bio-mass heater is used as an auxiliary heating source. A comprehensive mathematical thermal model was developed to represent the fully integrated system, which was implemented to determine the useful energy for two selected building configurations based in UAE; fully solar cooling powered one-floor office building and hybrid four-floor residential building at different percentages of solar penetration. The obtained results for the fully solar powered system, showed that about 159 kWh and 126 ton/year savings were achieved in the Annual Energy Consumption (AEC) and CO2 emissions, respectively. Based on the performed numerical studies on the integrated SHC system of the residential building, the maximum solar penetration of 20% was found to be optimum as it reduced AEC by 176 kWh and cut off CO2 emissions by 140 ton/year with a payback period of 4 years. © 2013 Elsevier B.V.

Hughes B.R.,Heriot - Watt University Dubai | Chaudhry H.N.,Heriot - Watt University Dubai | Ghani S.A.,Qatar University
Renewable and Sustainable Energy Reviews | Year: 2011

Heating, ventilating and air-conditioning (HVAC) systems play a vital part in ensuring the required comfort levels of residents inside building environments. However, most modern cooling equipments consume high levels of electrical power, thus create high energy consumption rates in buildings. The purpose of this review is to evaluate the common practice of implementing passive and active cooling technologies in buildings. Basic description along with the features and limitations of the techniques are outlined. Comparisons made on the electricity consumption and the capital expenditure has also been proposed. Alternatives such as utilizing heat-pipe heat exchangers for energy recovery have been described. The review highlights that wind towers are prospective alternatives to meet the demand of urban electricity utility along with its contribution to green building. © 2011 Elsevier Ltd. All rights reserved.

De Sa A.,Heriot - Watt University Dubai | Al Zubaidy S.,Heriot - Watt University Dubai
Applied Thermal Engineering | Year: 2011

The difference between the actual power generated by a gas turbine and the design rated power tagged on the gas turbine is observed whenever a gas turbine operates at site ambient conditions that vary from the stipulated ISO conditions. A detailed study and extensive logging of data has endorsed the well known existence of a direct relationship between the ambient temperature and the de-rating of gas turbine power output. The paper proposes an empirical relationship between the gas turbine's ability to generate power when exposed to site ambient conditions, such as the ambient temperature, which differ from ISO conditions. For every K rise in ambient temperature above ISO conditions the Gas Turbine loses 0.1% in terms of thermal efficiency and 1.47 MW of its Gross (useful) Power Output. This established relationship will assist the proper assessment of local power generation for installation planning and forecasting with special reference to Middle-eastern countries which are rapidly developing the application of Gas Turbine Inlet Air Cooling (GTIAC) technologies. This study was conducted for specific turbines SGT 94.2 and SGT 94.3 installed at the DEWA Power Station located at Al Aweer, H Phase II and III in Dubai, UAE. © 2011 Elsevier Ltd. All rights reserved.

Hughes B.R.,Heriot - Watt University Dubai | Mak C.M.,Hong Kong Polytechnic University
Energy and Buildings | Year: 2011

Commercial wind towers have been the focus of intensive research in terms of their design and performance. There are two main forces which drive the flow through these devices, external wind and buoyancy due to temperature difference. This study examines the relationship between these two forces and the indoor ventilation rate achieved. The work uses computational fluid dynamics (CFD) modeling to isolate and investigate the two forces and draw comparisons. The study found that as expected the external driving wind is the primary driving force providing 76% more internal ventilation than buoyancy driven flow, which is deemed secondary. Moreover the study found that the effect of buoyancy is insignificant without an external airflow passage other than the wind tower itself. The addition of an external airflow passage such as a window in combination with buoyancy force increased the indoor ventilation by 47%. Therefore the careful positioning of windows in conjunction with internal heat source has the potential to overcome the lack of external wind driven forces in dense urban environments. © 2011 Elsevier B.V. All rights reserved.

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