Refurbishment of public housing villas in the United Arab Emirates (UAE): energy and economic impact

© 2016, Springer Science+Business Media Dordrecht. This study aims at assessing the technical and economic benefits of refurbishing existing public housing villas in the UAE. Four representative federal public housing villas built between 1980s and 2010s were modeled and analyzed. The Integrated Environmental Solutions-Virtual Environment (IES-VE) energy modeling software was used to estimate the energy consumption and savings due to different refurbishment configurations applied to the villas. The refurbishment technical configurations were based on the UAE’s Estidama green buildings sustainability assessment system. The refurbishment configurations include upgrading three elements: the wall and roof insulation as well as replacing the glazing. The annual electricity savings results indicated that the most cost-efficient refurbishment strategy is upgrading of wall insulation (savings up to 20.8 %) followed by upgrading the roof’s insulation (savings up to 11.6 %) and lastly replacing the glazing (savings up to 3.2 %). When all three elements were refurbished simultaneously, savings up to 36.7 % were achieved (villa model 670). The savings translated to CO2 emission reduction of 22.6 t/year. The simple and discounted payback periods for the different configurations tested ranged between 8 and 28 and 10 and 50 years, respectively

Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

Introduction of PEM fuel-cell vehicles in the transportation sector of the United Arab Emirates

In this paper, a scheme is proposed whereby the United Arab Emirates government can achieve greater economic and environmental benefits associated with the introduction of proton-exchange membrane fuel-cell (PEMFC) vehicles in the transportation sector. Initially PEMFC vehicles would co-exist with the conventional internal-combustion (IC) vehicles and gradually increase in numbers until completely replacing IC vehicles by 2025. Our results predict that by 2025, the economic and environmental pollution caused by the business-as-usual approach (without PEMFC vehicles introduction) would cost $3.80x108 and 2.4x108 kg, respectively. The total economic and environmental savings in the 20 years span would be$23x108 and 14.4x108 kg, respectively. In addition, the average annual cost of PEMFC vehicles is $5061 dollars per year, which is approximately$180 dollars less than IC vehicles.Hydrogen energy PEM fuel-cell PEMFC vehicle and internal-combustion vehicle

Investigations on proton exchange membrane fuel cells with different configurations and flow fields

In this study, two mathematical models are developed. The first one is a simple mathematical approach that computes all transport and electrochemical parameters inside the different layers of a fuel cell regardless of its configuration. Through heat and mass transfer analogy, convective mass transfer coefficients at different Reynolds number are determined for both concentric cylindrical and conventional proton exchange membrane (PEM) fuel cells. Concentrations of oxygen and hydrogen are then determined at each layer of the fuel cell using steady-state diffusion analysis. The concentration equations are solved together with the electrochemical equations inside the fuel cell, to obtain the fuel cell voltage and power density. The results from this simple approach compared well with the existing numerical and experimental results. The second mathematical model is to study PEM fuel cell with conventional and non-conventional namely interdigitated flow fields. Through proper handling of the boundary conditions at the gas diffusion/catalyst layer interface, the numerical solution of the model resulted in the profiles of transport and electrochemical parameters in the cathode. Parameters such as pressure distribution, velocity profile, oxygen concentration, molar flux, current density, polarization and overall power density at different cell over-potentials in both flow fields were determined. The results demonstrates the superiority of interdigitated flow field over the conventional type in terms of overall performance and illustrated the importance of the convective term of the species equation in enhancing the reaction rates, leading to a significant improvement in the fuel cell performance. The effects of different parameters, such as cathode porosity, inlet oxygen mole fraction, and operating pressure on fuel cell performance have been studied using this 2-D mathematical model. Finally, a simple efficiency and economical analysis was formulated and implemented on PEM fuel cell with both conventional and interdigitated flow fields. The fuel cell efficiency analysis of both flow fields was determined in terms of first law efficiency. While, the fuel cell economics focused on annual fuel cost, annual capital cost and electricity cost as a function of a fuel cost at selected cell potentials. In addition, a minimum fuel cost to operate the fuel cell is determined in both conventional and interdigitated flow fields based on a nominal electricity cost of 0.08$/kW hr. Finally, a minimum cell cost is calculated in both flow fields based on the fuel cost of 10$/GJ and electricity cost of 0.08$/kW-hr

Assessments of primary energy consumption and its environmental consequences in the United Arab Emirates

Since its independence in 1971, the United Arab Emirates (UAE) took a giant leap toward achieving a high economic growth and urbanization. Consequently, primary energy consumption namely oil and natural gas has quadrupled in the past two decades such that energy consumption per capita was the highest in the world and the resulting carbon emission per capita was at least twice and 10 times higher than the developed countries and the world's annual average emission, respectively. In this paper, assessments of the UAE's primary energy consumption and its environmental consequences in the past two decades are carried out. The study covered major parameters such as urbanization, population and economic growths that influenced the country's energy consumption. Furthermore, the study suggested key remedial measures that could be deployed by local and national organizations in the country in order to consolidate their positions in mitigating country's primary energy consumption and environmental emissions. The proposed remedial measures are namely enhancing public awareness, achieving a lower population growth rate, maintaining a high economic growth rate, utilizing renewable energy resources, producing and utilizing hydrogen energy, implementing carbon sequestration technology and deploying energy management programs in various sectors.UAE Energy consumption Carbon emission Economic growth Urbanization