Study of a solar HDH desalination unit powered greenhouse for water and humidity self-sufficiency (original) (raw)
Related papers
2019
The countries in the Middle East and North Africa (MENA) region are suffering from the scarcity of freshwater resources. With the economic development and population growth, planning the additional water supplies is critical for this region. Desalination of saline water is, therefore, considered as a strategic alternative water resources and technology to be adopted in MENA region. On the other hand, open field agriculture in such conditions is not economical particularly with high ambient temperature and solar intensity. Agriculture Greenhouses (GH) present a suitable alternative for different plants growth for the region's desert. In most cases GHs can reduce about 90% of irrigating water demand compared open field. With the available high solar energy, integration of solar-GHdesalination presents a real challenge and is the field of newly funded N-M R&D proposal. This paper presents an integration of solar energy, agriculture GH and suitable desalination processes targeting the development and pilot testing of a novel stand-alone system that grows its energy and irrigation water demand.
HUMIDIFICATION-DEHUMIDIFICATION SYSTEM IN A GREENHOUSE FOR SUSTAINABLE CROP PRODUCTION
Prolonged aridity in the Sultanate of Oman has resulted in freshwater deficit in some parts of the country. In coastal areas, the aridity coupled with over-pumping of groundwater have often resulted in seawater intrusion. Looking for alternatives to provide freshwater for domestic, industrial and agricultural purposes is an ultimate goal for the government. The use of solar radiation in greenhouses to desalinate saline/brackish water was proposed as an alternative to provide freshwater for irrigation. This paper presents a study aimed at constructing and preliminary testing a humidification-dehumidification system in a Quonset greenhouse for producing freshwater. This greenhouse was modified to work with two humidifiers (i.e., evaporating pads), to increase water vapor inside the greenhouse as much as possible, and two dehumidifiers (i.e., condensers) to condense this water vapor. After evaporation, water leaving the humidifiers was cooler than the incoming water. This cooled water ...
Solar Driven Agricultural Greenhouse Integrated with Desalination System; Energy-Water-Food Nexus
2020
This study presents the effective performance of a sustainable solar driven agricultural greenhouse (GH) self-reliant of energy and irrigation water via desalination. The GH is furnished with infrastructures such as; (i) - an inlet condenser for cool air exchanger and partial water production, (ii) - an internal cavity for crop production (iii) - roof transparent solar distillers (TSD) for solar desalination and partial shading and (iv)- a thermal chimney for natural air ventilation. A mathematical model is developed to predict the performance of the sustainable GH system. A coupled approach of MATLAB/Simulink and computational fluid dynamics (CFD) based on three simulation models were used: solar radiation, thermal energy balance and CFD model. Two parametric studies were carried out. The first one analyzed the effects of different air velocity on the system thermal performance and natural ventilation rate. The second study assessed the effects of different covering material on the...
Water
The purpose of this study is the fabrication and performance evaluation of a new type of solar humidification–dehumidification (HD) desalination unit to supply sufficient fresh water for a seawater greenhouse in the MAKRAN coast in southeast Iran. In the proposed design, a particular type of air-to-air condenser is used. The cold air coming out of the greenhouse ventilation system (fan and pad) in summer and the cold ambient air in winter is used to supply the required cooling of the system. In this way, when cold air passes over the pipes in air-to-air condensers, condensation of water vapor occurs in the moist air inside the pipes, and fresh water is produced. Greenhouse fans, which have an air flow rate of around 20,000 m3/hr, are used to create this air flow. By fabricating two condensers, each using 42 rows of PVC pipes with a diameter of 75 mm, it is possible to produce 400 L of fresh water per day in a 400 m2 greenhouse. The required heating is provided by the solar farm, whi...
Solar Energy, 2003
The long-term aim of our research is to develop humidificationdehumidification desalination technology for farms in arid coastal regions that are suffering from salt infected soils and shortages of potable groundwater. The specific aim of our current study was to determine the influence of greenhouse-related parameters on a process, called Seawater Greenhouse, which combines fresh water production with growth of crops in a greenhouse system. A thermodynamic model was used based on heat and mass balances. The dimension of the greenhouse had the greatest overall effect on the water production and energy consumption. A wide shallow greenhouse, 200 m wide by 50 m deep gave 125 m 3 .d -1 of fresh water. This was greater than a factor of two compared to the worst-case scenario with the same area (50 m wide by 200 m deep), which gave 58 m 3 .d -1 . Low power consumption went hand-in-hand with high efficiency. The wide shallow greenhouse consumed 1.16 kW.h.m -3 , while the narrow deep structure consumed 5.02 kW.h.m -3 . Analysis of the local climate indicated that the structure should be built facing the NE direction. We are also in the process of building a commercial size Seawater Greenhouse at a site by the sea. The aim is to demonstrate the technology to local farmers and companies in the Arabian Gulf. The system will allow for the reclamation of salt-infected land by not relying, at all, on groundwater resources.
Biosystems Engineering, 2005
A thermodynamic simulation study was performed on the influence of greenhouse-related parameters on a desalination process that combines fresh water production using humidification-dehumidification with the growth of crops in a greenhouse system. Thermodynamic modeling has shown that the dimension of the greenhouse had the greatest overall effect on the water production and energy consumption. A wide shallow greenhouse, 200 m wide by 50 m deep gave 125 m 3 .d -1 of fresh water, compared to the worstcase scenario with the same area (50 m wide by 200 m deep), which gave 58 m 3 .d -1 . The wide shallow greenhouse consumed 1.16 kW.h.m -3 , while the narrow deep structure consumed 5.02 kW.h.m -3 . The construction of a prototype system in the Arabian Gulf will be presented as well as optimization studies of this structure. The benefits of the development of the Seawater Greenhouse for coastal regions in the Latin American and Caribbean Region will be discussed.
Water needs for agriculture, food production and drinking are considered one of the most critical challenges facing the world in the present days. This is due mainly to the scarcity and lack of fresh water resources, and the increasing ground water salinity. Most of these countries have a high solar energy potential. This potential can be best developed by solar desalination concepts and methods specifically suited for rural water supply, irrigation. In this paper, a humidificationedehumidification (HD) water desalination system with several technologies for irrigation and drinking needs in remote arid areas is introduced from technical and economic point of views. This study has investigated (1) detailed discussion of technical developments, economical and sustainable aspects; (2) benefits of the new design over traditional applications, desalination and other irrigation methods; (3) specific requirements and implementation challenges in remote and cold regions; (4) performance and reliability improvement possible techniques. Recommended researches and projects leading to high efficiency, economical and sustainable applications of some desalination devices driven by solar energy are highlighted.
This study proposes a new type of greenhouse for water re-use and energy saving for agriculture in arid and semi-arid inland regions affected by groundwater salinity. It combines desalination using reverse osmosis (RO), re-use of saline concentrate rejected by RO for cooling, and rainwater harvesting. Experimental work was carried at GBPUAT, Pantnagar, India. Saline concentrate was fed to evaporative cooling pads of greenhouse and found to evaporate at similar rates as conventional freshwater. Two enhancements to the system are described: i) A jet pump, designed and tested to use pressurized reject stream to re-circulate cooling water and thus maintain uniform wetness in cooling pads, was found capable of multiplying flow of cooling water by a factor of 2.5 to 4 while lifting water to a head of 1.55 m; and ii) Use of solar power to drive ventilation fans of greenhouse, for which an electronic circuit has been produced that uses maximum power-point tracking to maximize energy efficiency. Re-use of RO rejected concentrate for cooling saves water (6 l d -1 m -2 ) of greenhouse floor area and the improved fan could reduce electricity consumption by a factor 8.
Greenhouse Based Desalination for Sustainable Agriculture in Desert Climate
The Arab Region is characterized by arid and semi-arid conditions with very limited renewable water resources. Most of the surface water comes from transboundary streams and most of the groundwater resources are fossil in nature. Water quality degradation and excessive use of pesticides and herbicides in agriculture pose severe environmental and health risks. The underlying research is a joint effort between Cairo University and the Technical University of Berlin to develop technologies and strategies for sustainable pesticide free agriculture using saline or brackish water. This project builds on a previously implemented project in Spain by the German research partner that introduced the concept of Watergy, which presents an integrated desalination horticulture solar greenhouse. In this current research the Watergy greenhouse is further developed to meet more arid climate requirements, reduce construction costs, and increase resource utilization efficiency. Several lab scale experi...
This study proposes a new type of greenhouse for water re-use and energy saving for agriculture in arid and semi-arid inland regions affected by groundwater salinity. It combines desalination using reverse osmosis (RO), re-use of saline concentrate rejected by RO for cooling, and rainwater harvesting. Experimental work was carried at GBPUAT, Pantnagar, India. Saline concentrate was fed to evaporative cooling pads of greenhouse and found to evaporate at similar rates as conventional freshwater. Two enhancements to the system are described: i) A jet pump, designed and tested to use pressurized reject stream to re-circulate cooling water and thus maintain uniform wetness in cooling pads, was found capable of multiplying flow of cooling water by a factor of 2.5 to 4 while lifting water to a head of 1.55 m; and ii) Use of solar power to drive ventilation fans of greenhouse, for which an electronic circuit has been produced that uses maximum power-point tracking to maximize energy efficiency. Re-use of RO rejected concentrate for cooling saves water (6 l d-1 m-2) of greenhouse floor area and the improved fan could reduce electricity consumption by a factor 8.