Session: 11-42-01: Heat and Mass Transfer in Heating, Cooling, and Power Systems

Paper Number: 113015

113015 - Atmospheric Water Capture Potential in Arid Countries: An Experimental Investigation 

The decline of freshwater supply is a multifaceted problem that poses significant threats across the globe. Both developing and developed countries suffer from the consequences of the depletion of natural fresh water resources in several aspects. In MENA region, the ground water reserves are extensively exploited. Consequently, several countries such as Saudi Arabia rely on desalination as a main source to produced drinkable water. Although desalination can be regarded as a well-established solution, it requires relatively high capital investment and adequate infrastructure. Moreover, extensive reliance on desalination raises the concerns about the environmental effect that the brine rejection process has on the biodiversity, fisheries, and coastal communities of the Arabian Gulf. For developing countries, the access to clean water doesn’t only hinder both the economic and social growth but also poses significant threats on the health conditions. As an example, in Egypt, the Nile River, which is the primary source of freshwater, has diminished as a result of prolonged droughts and an increasingly hot and arid climate along with the construction of dams. The lack of proper infrastructure delays the implementation of large-scale desalination plants. On the other hand, one of the major advantages of the climate in such regions is the widespread presence of high humidity and temperatures. This presents an opportunity for implementing an atmospheric water extraction technology that can be used in addition to the conventional desalination methods. The atmospheric water generation (AWG), as a solution addressing the aforementioned problems, is regarded as a relatively simple and cost-effective method to generate freshwater from air. In addition, AWG may have a significant potential if implemented in poor countries that have limited infrastructure. This study aims to evaluate the feasibility of AWG technology in countries that have arid climates. In the present work, an experimental setup is designed, built, and tested to produce drinkable water by removing and collecting moisture from humid air. The proposed setup is driven by a conventional vapor compression cycle. An aluminum-copper finned tube evaporator and condenser are used. Both are placed perpendicular to the airflow direction in a horizontal configuration. A controlled fan is placed after the condenser to drive the airflow throughout the system. The inlet and exit temperatures of the evaporator were monitored and controlled to ensure that the evaporator is operating under the dew point temperatures throughout the experiments. As the air flows over the cold surface of the evaporator, water is condensed and freshwater droplets are formed. To enhance the water collection, a set of vibrators are proposed and implemented. The vibrators’ main function is to reduce the effect of surface tension which causes the adhesion of water droplets to the evaporator’s metallic cold surface. The continuous removal of water droplets is crucial to increases the total amount of water produced. The proposed configuration allows the cooling of the condenser directly by ambient air or using the dehumidified cold air exiting the evaporator which allows for more energy recovery. The air speed, relative humidity, and ambient temperature are monitored throughout the experiments. Results show that the system has the potential to produce around 20 liters/m² per day. Under certain operational conditions, the AWG system can increase water availability which can be further utilized in applications such as green roofs in arid countries.

 

Presenting Author: Muhammad I. Rashad Alexandria University

Presenting Author Biography: Mr. Rashad is a lecturer in the Mathematics and Physics Engineering Department at the Faculty of Engineering, Alexandria University, where he earned his B.Sc. in Mechanical Engineering followed by his M.Sc. in Thermal Engineering. He received his doctorate in Energy Resources Engineering from the Egypt-Japan University of Science and Technology (E-JUST) as a part of a student exchange program between Egypt and Japan. He participated in several projects in alternative energy among which he has participated in the design and implementation of a fully operational solar Stirling unit, the design and manufacture of a parabolic collector with two axes of solar tracking mechanism, and a parabolic trough with a single axis of solar tracking mechanism. He was also the Co-founder and board member of Aquila CNC systems and SUNPave for solar PV systems.

Authors:

Muhammad I. Rashad Alexandria University
Nada Mourad Alexandria University
Abdallah Mubarak Alexandria University
Hend Faiad Alexandria University
Shehab Ahmed King Abdullah University of Science and Technology
Mohamed Farahat Menofia University