Qatar University (QU) is to develop the country’s first solar agriculture greenhouse in collaboration with the Department of Agricultural Research at the Ministry of Municipality and Environment (MME), it was announced Sunday.
QU has been provided a grant by Qatar National Research Fund (QNRF), for the project to develop a thermally insulated greenhouse that allows the entry of optimum solar radiation levels through negative linear fresnel lenses on the roof.
Dr Saud Ghani
The performance of the proposed greenhouse in terms of providing the required levels of solar radiation for plant growth and the reduction in cooling load were assessed using ray tracing simulations, cooling load calculations and field trials in Nabati farm.
Dr Saud Ghani, lead researcher of greenhouse project and professor of mechanical engineering at College of Engineering said, “Qatar has set food security as a priority for the country and set out a commitment to sustain about 70% self-sufficiency on greenhouse vegetables. Achieving sustainable food security was further ascertained by the ongoing geopolitical tensions and the unjust blockade on the country.”
Though greenhouses provide an optimised and controlled growth environment for plants to maximise yield. they can be energy intensive.
In comparison to a conventional greenhouse, the monthly cooling load of the proposed greenhouse is about 80% less. Therefore, the project can achieve the benefits of a closed greenhouse while overcoming the high cooling demand, in subtropical and arid regions.
The design of the solar greenhouse aims to overcome two identified shortcomings of the conventional greenhouse during the hot season, its highly transparent and conductive structure. The highly transparent walls of a greenhouse are desired during the winter season where the amount of available solar radiation is relatively low. However, excessive amounts of solar radiation enter the greenhouse during the hot season due to its high transparency. The conductive nature of the typical greenhouse walls causes undesired heat gain.
To overcome the first shortcoming, the entry of sunlight to the greenhouse is only allowed through negative linear fresnel lenses that are fitted in rows in its roof corresponding to the plant grow lines underneath. The lenses are placed directly above the plants grow rows. They act as a roof mounted lighting system, dispersing sunlight over the plants. The remaining walls of the greenhouse are covered with thermal insulation rolls, thus, overcoming the second shortcoming.
Dr Ali al-Kharboutli, consultant to the Agricultural Research Department, MME said, “The research depends on the use of a number of technologies that are based on the Fourth Industrial Revolution 4.0 and its transformation into an integral part of the agricultural community by developing the greenhouse design, manufacturing, cooling and lighting systems. The research extends to creating a sustainable growing medium suitable for the Qatari agricultural environment from local organic degradable wastes with special specifications for commercial production. It is expected that the new growing medium environment will provide a viable substitute for the imported environments currently used in agriculture.”
“The design of these agriculture greenhouses was carried out using the latest technologies in the field of engineering and agriculture," according to Hamad Saket al-Shammari, director of the Agricultural Research Department, MME.
The MME is offering the required agriculture land needed for the construction of the proposed greenhouse and provides other agricultural resources needed such as irrigation water, power, seeds, fertilisers and chemicals. "The new greenhouse is considered a to be a quantum leap in the field of protected agriculture, by increasing quantity and quality while reducing the operating costs of energy and water consumption,” al-Shammari added.