ROOFTOP GREENHOUSE

ROOFTOP GREENHOUSE

Jerusalem, ISRAEL
Entrepreneur: K.B.K HON Holdings

Palram

With the majority of the people now living in cities and urban areas, there is an ongoing demand to capitalize on the natural resources without exploiting them. This rooftop greenhouse takes the concept of vertical farming to another level not only by making use of a space with commercial production of vegetables near a city center profitable, but also by doing it in an arid desert. This advanced commercial greenhouse is located in Southern Israel, a five minute drive from one of Israel’s major metropolitan centers. It supplies fresh vegetables to the city’s markets with a minimal expenditure of energy for transportation. It makes use of the greenhouse to cool the building during the day, and to heat it during the night. At first glance, it seems that you are in an ordinary industrial-commercial park containing high-technology enterprises, industrial manufacturing plants and logistic centers. But when you climb up to the roof of one of these industrial facilities, you will gasp in amazement. The third floor is occupied by a 4,500 square meter commercial greenhouse which produces fresh herbs with a yield that would require 200,000 square meters of cultivated land if it were to be grown in an open field. When considering the climatic conditions of this dry and windy desert area, the magnitude of this innovation becomes even greater. The crops are grown by hydroponics, thus does not require irrigation pipes, heavy machinery, and, more importantly, is pesticide free. All the water and fertilizers are recycled back into the growing system. This system brings food production closer to city centers while freeing agricultural lands to raise other crops. Overall, this innovative project can serve as a model of how to utilize roofing in urban areas, while saving natural resources and energy costs. One of the main considerations when constructing this greenhouse was its energy efficiency. The aim was to allow sufficient light penetration while ensuring thermal insulation. The rooftop greenhouse is covered with clear embossed corrugated polycarbonate sheets which allow optimal light transmittance, combined with a high level of light diffusion, dispersing the light evenly and preventing shade patches and improving plant morphology and development. By thinking outside the box and using innovative technology, one entrepreneur managed to challenge the climatic obstacles and make the desert bloom under a polycarbonate covering. Since all construction materials had to be elevated by a crane to the roof, polyethylene sheets were not considered as they would have to be replaced on annual basis. The lightweight greenhouse structure made it possible to erect such a large structure on a roof that was not originally designed to withstand the weight of an additional floor. Corrugated sheets of 7.4 meters long, starching from ridge to gutter, were installed. This length enables minimal overlaps, thus sparing material and metal structure. PALRAM’s unique side lap fastening accessories were used at the corrugation overlaps, turning the greenhouse roof into a single solid unit that prevents energy loss at night and enables controlling heat gain and loss during the day. These tailor made side lap profiles also prevent tearing at strong winds and hermetically seals against dust accumulation, insects and water leakage.