From ancient times, homes and other buildings in countries with abundant sunlight have often featured a central open-air courtyard which allows for good ventilation as well as greater penetration of daylight. In modern air-conditioned buildings, this open-air concept as been replaced by the atrium, an enclosed area roofed by transparent material - often glass - which allows daylight through.

In the MEWC building, the atrium is a central element regarding function, aesthetics, visual comfort and energy efficiency. All visitors to the building have to pass through the four-storey high atrium whic boasts a lot of greenery in a spacious and well-lit enclosure. This atrium provides daylight deep into the heart of the building, which would otherwise have been very dark. Thus, people working in and around the area have a pleasing and stimulating green environment, in addition to visual contact with the outdoors.

At the top of the atrium is a solar wall, or "thermal flue". The two-storey black wall with vertical glass glazing in front acts as a ventilation system driven by natural forces. Solar radiation heats up the black wall, which in turn heats up the air in a 800mm gap between the wall and the glass. The hot air rises as in a chimney and escapes through vents. The resulting vacuum "sucks" outside air into the ground level of the atrium through sliding doors. When this air passes through the sliding doors, a spray mist system emits water particles, thereby cooling the air by a couple of degrees.