On the rooftop of the restaurant of the IFSB, the institute for building sector training, there’s a pilot greenhouse that students utilize for training purposes. “This 380 sqm greenhouse is built with a metal supporting structure,” says Marcel Deravet, project manager. “The structure for the façade is made out of aluminum, with double-glazing glass. “Why double?” says Marcel. “Because we want to be energy efficient, and there are different elements to take into account. This high-performance double glazing has an 89% light transmission.” This is a crucial aspect, Marcel explains, as every ‘percent’ lost in light transmission has an impact on the production inside the greenhouse.
The greenhouse is also heated with radiant tubes around the structure. “There’s no underfloor heating,” he explains. “This is because we are above a restaurant, which is, of course, heated. Even if the slab is insulated, we still get energy transmission, and the floor remains at a good temperature.”
The floor is indeed made of concrete, “As well as the north and south walls,” Marcel remarks. That allows them to retain the heat during the day and release it during the night, gaining those few degrees that would do the trick. “And it also saves energy.”
Above the greenhouse, there’s a ventilation system. “The system is connected to the ventilation of the offices and classrooms here. This heat goes through a heat exchanger, and we get the residual heat for the greenhouse.” In terms of reuse, also CO2 is taken from the classroom. “People breathe and produce CO2. So, we take that from classrooms and use it in the greenhouse.”
A hydroponic grow system is in place in the greenhouse, but they don’t fully load it with plants. “The load is about 40kg per sqm,” Marcel remarks. “This makes it feasible for a rooftop greenhouse without too much load.” And the fact that the greenhouse is on top of a restaurant cuts down the CO2 for transportation. “Vegetables are harvested and taken down into the kitchen.”
But one of the most interesting aspects of this rooftop greenhouse is that it is perfectly integrated with the surrounding buildings and environment. Being an urban farm, Marcel explains, the rooftop greenhouse doesn’t have to be sustainable and efficient, but it also has to be aesthetically fitting. “The height of the greenhouse is 7.5 meters. In this way, it fits perfectly with the building behind.” Thus, it also makes a lot of sense that architects and engineers train inside this facility. “It is perfectly integrated with the urban environment, and it is aesthetically fitting.”