• Energy Research

AbstractScarcity of fresh water sources, rapid industrial development and increase of urban population in arid regions like UAE lead to tremendous increase in bottled water dependency for drinking purpose. The bottling process right from treatment to delivery is highly unsustainable and hence we focus on the issue of providing pure drinking water in a sustainable way through solar domestic hot water (SDHW) systems. The shift towards sustainability in the oil rich region and recent growth of interest on Membrane Distillation (MD) technique at small scale application development by coupling with solar energy source has motivated us to develop a combined SDHW-MD pilot unit for feasibility analysis. Present application is to co-generate 20 l/day of drinkable water and 250 l/day of domestic hot water for a single family house/villa in UAE region. Experiments are performed for municipal water purification and compared with empirical equation based model developed using laboratory experimental data along with PolySun simulations. Monthly energy consumption and water production profiles have been obtained which would form a basis for detailed dynamic simulation and optimization of system performance.

In the present study, heat transfer and entropy generation in the spiral corrugated heat exchanger used in the solar pond have been numerically studied. The thermal boundary condition of the third type has been selected for simulation and different geometric parameters have been studied to improve heat transfer and reduce entropy generation. New correlations based on experimental data have been used to validate the simulation. The results were obtained by changing the parameters such as the number of corrugations, the twist number of the corrugations, and the change of the Reynolds number. Also, dimensionless parameters have been defined to investigate the increase of heat transfer and decrease of entropy generation based on the first and second laws of thermodynamics, and finally, the optimal geometries have been introduced by the NH multi-criteria parameter. The simulation results showed that the corrugation creation on the tube will increase heat transfer and decrease entropy generation. Therefore, it was found that the twist number of the corrugation has a greater effect than the number of corrugations. In the best case, when the number of corrugations and their twist is high, the heat transfer improvement number (NH) can grow up to 89%, which will decrease with the increase of Reynolds number.

Energy-efficient retrofitting of building envelopes is necessary to reduce global carbon emissions and to reach net-zero goals. Cooling energy demand-dominated countries in the GCC region require simple and effective strategies to reduce building sector energy loads. One such approach is using high solar reflective index (SRI) paints to retrofit building roofs and walls. However, the hot and desert conditions of the region pose a barrier to maintaining consistent radiative properties throughout their life cycle. To this extent, research is limited in the region. The novelty of this work is to qualitatively assess the aging characteristics of high SRI or cool paints and estimate the energy savings for their application in residential buildings. The work encompasses comprehensive lab, pilot, and real-scale experimental studies combined with theoretical modeling for dynamic evaluation. Dynamic simulations enabled to determine the time-dependent aging effect on the energy savings performance of the building retrofitted with cool roof and wall paints. A case study on a townhouse in UAE showed annual energy savings of 34% considering cool roofs, walls, and window films. Aging studies showed SRI reduction of 36% and 25%, respectively, for cool roofs and walls during the first 3 years. The corresponding energy-saving reductions ranged from 31 to 44% for the white roof to dark wall colors. Using the initial values of SRI in energy models overestimates saving by 10% per year. Considering the aging effects, this work provides insights into cool paint retrofit potential on energy, economic savings, and CO2 reductions for four major cities in the GCC region.

Water is the most desirable and sparse resource in Gulf cooperation council (GCC) region. Utilization of point-of-use (POU) water treatment devices has been gaining huge market recently due to increase in knowledge of urban population on health related issues over contaminants in decentralized water distribution networks. However, there is no foolproof way of knowing whether the treated water is free of contaminants harmful for drinking and hence reliance on certified bottled water has increased worldwide. The bottling process right from treatment to delivery is highly unsustainable due to huge energy demand along the supply chain. As a step towards sustainability, we investigated various ways of coupling of membrane distillation (MD) process with solar domestic heaters for co-production of domestic heat and pure water. Performance dynamics of various integration techniques have been evaluated and appropriate configuration has been identified for real scale application. A solar combi MD (SCMD) system is experimentally tested for single household application for production 20 L/day of pure water and 250 L/day of hot water simultaneously without any auxiliary heating device. The efficiency of co-production system is compared with individual operation of solar heaters and solar membrane distillation.

The demands for space air conditioning and clean drinking water are relatively high in Middle East North African (MENA) countries. A sustainable and innovative approach to meet these demands along with the production of domestic hot water is experimentally investigated in this paper. A novel solar thermal poly-generation (STP) pilot plant is designed and developed for production of chilled water for air conditioning using absorption chiller, clean drinking water with membrane distillation units and domestic hot water by heat recovery. The STP system is developed with a flexibility to operate in four different modes: (i) solar cooling mode (ii) cogeneration of drinking water and domestic hot water (iii) cogeneration of cooling and desalination (iv) trigeneration. Operational flexibility allows consumers to utilize the available energy based on seasonal requirements. Performance of STP system is analyzed during summer months in RAKRIC research facility. Energy flows in STP pilot plant during peak load operations are analyzed for all four modes. STP system with trigeneration mode utilizes 23% more useful energy compared to solar cooling mode, which improves overall efficiency of the plant. Economic benefits of STP with trigeneration mode are evaluated with fuel cost inflation rate of 10%. STP plant has potential payback period of 9.08 years and net cumulative savings of $454,000 based on economic evaluation.

Tri-generation is one of the most efficient ways for maximizing the utilization of available energy. Utilization of waste heat (flue gases) liberated by the Al-Hamra gas turbine power plant is analyzed in this research work for simultaneous production of: (a) electricity by combining steam rankine cycle using heat recovery steam generator (HRSG); (b) clean water by air gap membrane distillation (AGMD) plant; and (c) cooling by single stage vapor absorption chiller (VAC). The flue gases liberated from the gas turbine power cycle is the prime source of energy for the tri-generation system. The heat recovered from condenser of steam cycle and excess heat available at the flue gases are utilized to drive cooling and desalination cycles which are optimized based on the cooling energy demands of the villas. Economic and environmental benefits of the tri-generation system in terms of cost savings and reduction in carbon emissions were analyzed. Energy efficiency of about 82%–85% is achieved by the tri-generation system compared to 50%–52% for combined cycles. Normalized carbon dioxide emission per MW·h is reduced by 51.5% by implementation of waste heat recovery tri-generation system. The tri-generation system has a payback period of 1.38 years with cumulative net present value of $66 million over the project life time.

La disponibilidad de amplios recursos de energía solar tiene una importancia significativa para las islas pobladas, ya que representa una vía vital para garantizar el suministro de energía sostenible y reducir la dependencia de fuentes de energía externas. El sistema propuesto está diseñado para ofrecer soluciones residenciales, proporcionando una respuesta prometedora para satisfacer las diversas necesidades energéticas de las islas modernas. Este innovador sistema integra colectores solares cilindroparabólicos, un ciclo Rankine orgánico en cascada (ORC), una unidad de producción de hidrógeno mediante electrólisis y un sistema de desalinización de agua a través de módulos de membrana. Al emplear una metodología optimizada, este sistema mejora la eficiencia térmica de la configuración propuesta y permite a las comunidades isleñas acceder a los recursos de gas natural. Se ha elaborado un sólido código de programación para evaluar exhaustivamente el sistema desde los puntos de vista de la energía, la exergía, la economía y el medio ambiente. El sistema está diseñado para lograr una serie de objetivos, incluida la generación de 1,2 MW de electricidad, el cumplimiento de una carga de refrigeración de 460 kW, la producción de 9,7 kg/h de hidrógeno y el suministro de 33 kg/s de agua desalinizada. Además, el gas natural se entrega a la red de consumo a un ritmo de 3,09 kg/s. La evaluación financiera, que incluye la inversión inicial y el mantenimiento continuo, muestra que la tasa de coste para todo el sistema es de 142 $/h, con un coste nivelado estimado de 33,2 céntimos/m3 para el agua dulce. Los hallazgos de la evaluación ambiental indican que el sistema propuesto tiene un potencial significativo para mitigar las emisiones de dióxido de carbono (CO2), con una tasa de reducción máxima de 254 kg/h. Esta reducción en las emisiones de CO2 conduce a una disminución correspondiente en la tasa de coste de emisión de CO2, estimada en aproximadamente 7 $/h. La disponibilité de vastes ressources d'énergie solaire revêt une importance significative pour les îles peuplées, car elle représente un moyen essentiel d'assurer un approvisionnement énergétique durable tout en réduisant la dépendance à l'égard de sources d'énergie externes. Le système proposé est conçu pour offrir des solutions résidentielles, offrant une réponse prometteuse pour répondre aux besoins énergétiques variés des îles modernes. Ce système innovant intègre des capteurs solaires à auges paraboliques, un cycle de Rankine organique en cascade (ORC), une unité de production d'hydrogène par électrolyse et un système de dessalement de l'eau à travers des modules membranaires. En utilisant une méthodologie optimisée, ce système améliore l'efficacité thermique de la configuration proposée et permet aux communautés insulaires d'accéder aux ressources en gaz naturel. Un code de programmation robuste a été conçu pour évaluer de manière exhaustive le système du point de vue de l'énergie, de l'exergie, de l'économie et de l'environnement. Le système est conçu pour atteindre une gamme d'objectifs, y compris la production de 1,2 MW d'électricité, répondant à une charge de refroidissement de 460 kW, produisant 9,7 kg/h d'hydrogène et fournissant 33 kg/s d'eau dessalée. En outre, le gaz naturel est livré au réseau grand public à un débit de 3,09 kg/s. L'évaluation financière, qui comprend l'investissement initial et la maintenance continue, montre que le taux de coût pour l'ensemble du système est de 142 $ / h, avec un coût nivelé estimé à 33,2 Cent/m3 pour l'eau douce. Les résultats de l'évaluation environnementale indiquent que le système proposé présente un potentiel important d'atténuation des émissions de dioxyde de carbone (CO2), avec un taux de réduction maximal de 254 kg/h. Cette réduction des émissions de CO2 entraîne une diminution correspondante du taux de coût des émissions de CO2, estimé à environ 7 $ / h. The availability of ample solar energy resources holds significant importance for populated islands as it represents a vital avenue for ensuring sustainable energy provision while reducing reliance on external energy sources. The proposed system is designed to offer residential solutions, providing a promising answer to fulfill the varied energy requirements of modern islands. This innovative system integrates parabolic trough solar collectors, a cascaded organic Rankine cycle (ORC), a hydrogen production unit via electrolysis, and a water desalination system through membrane modules. By employing an optimized methodology, this system enhances the thermal efficiency of the proposed setup and enables island communities to access natural gas resources. A robust programming code has been crafted to comprehensively evaluate the system from the standpoints of energy, exergy, economics, and the environment. The system is engineered to accomplish a range of objectives, including the generation of 1.2 MW of electricity, meeting a cooling load of 460 kW, producing 9.7 kg/h of hydrogen, and supplying 33 kg/s of desalinated water. In addition, natural gas is delivered to the consumer network at a rate of 3.09 kg/s. The financial assessment, which includes the initial investment and ongoing maintenance, shows that the cost rate for the whole system is 142 $/h, with an estimated levelized cost of 33.2 Cent/m3 for fresh water. The findings of the environmental assessment indicate that the proposed system holds significant potential for mitigating carbon dioxide (CO2) emissions, with a maximum reduction rate of 254 kg/h. This reduction in CO2 emissions leads to a corresponding decrease in the CO2 emission cost rate, estimated to be approximately 7 $/h. إن توافر موارد الطاقة الشمسية الوفيرة له أهمية كبيرة للجزر المأهولة بالسكان لأنه يمثل وسيلة حيوية لضمان توفير الطاقة المستدامة مع تقليل الاعتماد على مصادر الطاقة الخارجية. تم تصميم النظام المقترح لتقديم حلول سكنية، مما يوفر إجابة واعدة لتلبية متطلبات الطاقة المتنوعة للجزر الحديثة. يدمج هذا النظام المبتكر مجمعات الطاقة الشمسية ذات القطع المكافئ، ودورة رانكين العضوية المتتالية (ORC)، ووحدة إنتاج الهيدروجين عبر التحليل الكهربائي، ونظام تحلية المياه من خلال وحدات الغشاء. من خلال استخدام منهجية محسنة، يعزز هذا النظام الكفاءة الحرارية للإعداد المقترح ويمكّن المجتمعات الجزرية من الوصول إلى موارد الغاز الطبيعي. تم وضع رمز برمجة قوي لتقييم النظام بشكل شامل من وجهات نظر الطاقة والطاقة الخارجية والاقتصاد والبيئة. تم تصميم النظام لتحقيق مجموعة من الأهداف، بما في ذلك توليد 1.2 ميجاوات من الكهرباء، وتلبية حمل تبريد قدره 460 كيلووات، وإنتاج 9.7 كجم/ساعة من الهيدروجين، وتوفير 33 كجم/ثانية من المياه المحلاة. بالإضافة إلى ذلك، يتم تسليم الغاز الطبيعي إلى شبكة المستهلك بمعدل 3.09 كجم/ثانية. يوضح التقييم المالي، الذي يتضمن الاستثمار الأولي والصيانة المستمرة، أن معدل التكلفة للنظام بأكمله هو 142 دولارًا في الساعة، بتكلفة تقديرية قدرها 33.2 سنت/متر مكعب للمياه العذبة. تشير نتائج التقييم البيئي إلى أن النظام المقترح ينطوي على إمكانات كبيرة للتخفيف من انبعاثات ثاني أكسيد الكربون (CO2)، مع معدل خفض أقصى قدره 254 كجم/ساعة. ويؤدي هذا الانخفاض في انبعاثات ثاني أكسيد الكربون إلى انخفاض مقابل في معدل تكلفة انبعاثات ثاني أكسيد الكربون، الذي يقدر بنحو 7 دولارات في الساعة.

With the enhanced industrial and domestic energy needs, there is a great urge for renewable energy sources because of their eco-friendly nature. Solar energy is crucial among renewable energy sources and there is a great need to optimize and enhance the performance of solar energy usage that is mainly dependent on the system components. The current work has been aimed to discuss the fault detection of photovoltaic (PV) modules by evaluating an efficient, facile inspection algorithm electrical analysis for real-time applications. The paper presents a real-time experimental model for infrared thermography using a thermal imager mounted on a tripod at a suitable distance from the PV modules to capture the images in the best possible way. A novel hybrid algorithm has been proposed and the fault detection along with the electrical parameter analysis has been accurately performed on the PV modules to analyze and process various externally induced faults in the PV systems.