Significance Statement
Solar desalination technology is favorable due to its positive impact on environment but their cost effectiveness remains a major challenge. The two commonly used solar desalination technologies are the photovoltaic reverse osmosis (PV-RO) and solar humidification-dehumidification desalination system. While the latter requires less expertise in installation and maintenance which makes them more suitable for remote regions, unit cost of produced fresh water using PV-RO is currently lower than humidification-dehumidification desalination system.
Abd El-Aziz et al. (2016) presented an optimization of a solar-powered humidification-dehumidification HDH desalination system for remote areas where assumptions were only made on minimal external electric power. The work published in Journal of Solar Energy Engineering provided modifications on previous work, seeking to improve system performance in terms of unit cost of fresh water production. The authors modified model done on previous work by Abd El-Aziz et al. ASME, 2013 addresses problems such as negative effect of condensation performance, limitation of saline water temperature to 60°C leading to air capacity for water vapor less than 0.153Kg vapor/Kg air and expensive solar tank in solar water heater (SWH).
The modified model addressed the problems discussed above by firstly disconnecting the condenser from inlet water stream to operate on an independent coolant supply with a constant flow rate, solar air heater (SAH) added before the humidifier allows higher outlet air temperatures and higher humidity ratios and lastly, removal of the solar tank.
The authors considered a small-scale desalination plant operating near city of Hurghada in Egypt. Cost factor was assumed to be 55% while plant lifetime was assumed to be 30 years which is a typical value for the type of equipment considered.
Optimization and simulation results for a system with both large and small solar water heater area AC,W=1000m2 and AC,W=100m2 showed that unit cost of produced fresh water relative to previous work was reduced by about 75% for new cost function and by 56% for original cost function which is due to improved humidification and condensation performances. Specific energy consumption Esp was found to be in the range of 400-550 KWh/m3 depending of the system size which is still within the range reported in the literature (120-550 KWh/m3).
Disconnecting the condenser to utilize a high constant coolant flow rate increased the quantity of distilled water obtained from installed condenser which relates to a reduction in unit cost of production. The smallest system with 7.8m3/day had a unit cost of $1.7/m3 while most energy-efficient system had a unit cost of $5.7/m3 for capacity of 5m3/day. The minimum unit cost of $1.3/m3 was obtained which is 57% lower than reported range of previous systems of $3-7/m3.
For optimum 500m2 system, there was enough provision of potable water for a small town of 1000 to 3000 inhabitants and from economic point of view, it could be inferred that the system would have a payback period of 10 years in Hurghada.
Finally, Heuristic gradient projection optimization was much more efficient and required only about 10% of function evaluations required by unconstrained genetic algorithms optimization to converge.
The optimization and improved humidification and condensation performance achieved in this study have shown major cost reduction in production.
About The Author
Khalid M. Abdelaziz is a young researcher who is currently working on his PhD degree. He works as an assistant lecturer at the department of Mechanical Design and Production, Cairo University. Design Optimization is the main theme of his work, while application to various types of systems/models is his main interest. His current publications are concerned with cost optimization of solar water desalination system models, where a low cost configuration was studied for remote locations. These publications were part of USA/Egypt joint research project.
Currently he is working on the optimization of truss/frame structures using a novel optimization technique which reduces the amount of computational work required. In addition, he is also considering possible improvements to the latest solar desalination system model developed to further reduce the cost of water production and/or realize different implementation market segments.
About The Author
Karim Hamza got his B.Sc. (1998) in Mechanical Design and Production and M.Sc. (2001) in Mechanical Engineering from Cairo University (Egypt), while also working at a family-owned business (1995-2001) designing steel structures, water tanks and conveyer lines. He then joined the Ph.D. program at the University of Michigan, Ann Arbor, and soon thereafter became an active member in the research community of the ASME Design Automation Conference. His Ph.D. (2008) focused on optimal design of vehicle structures for crashworthiness, but maintained a broader interest in the co-development of process models and optimization approaches. As a post-doc (2009-2012, University of Michigan), he worked on a number of energy sustainability projects including solar hydrogen production and water desalination. In 2012, he became a consultant to Future of Mobility Research Division (FRD) at Toyota Research Institute, North America (TRINA), and later joined their team (2015) as an in-house contractor research scientist. Karim’s research at TRINA-FRD focuses on the societal impacts of next-generation transportation systems including electrified powertrains and automated vehicles.
About The Author
Mohamed El-Morsi is an associate professor in the Department of Mechanical Engineering at the American University in Cairo, Cairo-Egypt. Dr El-Morsi received his B.Sc. and M.Sc. degrees in Mechanical Engineering from Ain Shams University, Cairo-Egypt. In 2002, he received his Ph.D. from the University of Wisconsin-Madison. In 2007, he was awarded the Chevening Fellowship from the Foreign & Commonwealth Office, UK to study energy efficiency for three months at the Institute of Energy and Sustainable Development, De Montfort University, Leicester, UK. Dr El-Morsi is one of the co-founders of the Solar Energy Development Association in Egypt.
About The Author
Ashraf Nassef got his B.Sc. (1987) in Mechanical Engineering and M.Sc. (1990) in Mechanical Engineering from Cairo University (Egypt). He then obtained his PhD. from McMaster University, Canada (1996). Between 1995 and 1998 he worked in the University of Windsor (Canada) and later as an assistant professor in Cairo Univ. In 2002 he joined the American University in Cairo where he is currently a professor in the Mechanical Engineering Department. He served also as an adjunct professor in the University of Western Ontario, Canada. He has been active with the community of the ASME Design Automation Conference and acted as the liaison professor for Africa. His research lies in the area of tolerancing, heuristic optimization techniques and structural optimization.
About The Author
Sayed Metwalli is currently Professor Emeritus of Machine Design and past Chair of Mechanical Design and Production Department at Cairo University, Egypt. He received his BS (Mech. Eng.) from Cairo University, Egypt (1965). He earned his MS and PhD (Mech. Eng.) from State University of New York at Buffalo, USA, (1970) and (1973) respectively. He conducted research and taught at North Carolina State University and at the University of Central Florida, USA and holds a US patent.
His research interest is in design optimization theory, developing algorithms, and CAD/CAM software, with particular emphasis on optimum synthesis of mechanical components and systems including dynamics and controls for multitude of applications. He has conducted sponsored research with DOD/NRL, UNESCO, IBM-UK, NSF, EPA and the USAID. His work with various manufacturers successfully implemented CAD and design optimization in their product design and development. He is an ASME life fellow, fellow ESME, registered consultant, and has been registered PE in Florida.
About The Author
Kazuhiro Saitou is a Professor with the Department of Mechanical Engineering at the University of Michigan, Ann Arbor, MI, USA. He received the B.Eng. degree in mechanical engineering from the University of Tokyo, Tokyo, Japan, in 1990, and the M.S. and Ph.D. degrees in mechanical engineering from the Massachusetts Institute of Technology, Cambridge, MA, USA, in 1992 and 1996, respectively.
His research interest is computational optimal synthesis of products and systems with applications ranging from automotive and transportation systems to manufacturing and biomedical systems.
Journal Reference
Khalid M. Abd El-Aziz 1, Karim Hamza2, Mohamed El-Morsi3, Ashraf O. Nassef4, Sayed M. Metwalli 1, Kazuhiro Saitou2. Optimum Solar Humidification–Dehumidification Desalination For Microgrids and Remote Area Communities, Sol. Energy Eng 138(2), 021005 (Feb 01, 2016) (8 pages)
Show Affiliations
- Department of Mechanical, Design and Production, Cairo University, Cairo 12316, Egypt .
- Mem. ASME , Department of Mechanical Engineering, University of Michigan, Ann Arbor, .
- Mem. ASME, Department of Mechanical Engineering, American University in Cairo, New Cairo 11835, Egypt;Department of Mechanical Engineering, Ain Shams University, Cairo 11566, Egypt .
- Mem. ASME , Department of Mechanical Engineering, American University in Cairo, New Cairo 11835, Egypt .
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