Al-Nouq Square, Msheireb Downtown, Doha, Qatar
The development of downtown Msheireb, also known as the "Heart of Doha", is a project covering an area of 31 hectares (76 acres) with the aim of revitalizing and preserving the historic. Qatar has a subtropical climate with high humidity and hot temperatures with highs of 122°F / 50°C in the shade and averages around 104°F / 40°C in July and August.
Al Baraha Square is a large public square framed by the Cultural Forum and the Mandarin Oriental Hotel. Its unique feature is that it can be completely shaded, making it a year-round meeting place for residents and visitors with outdoor comfort. The innovative "roof" design, developed in collaboration, has a construction of dozens of horizontal axes above the plaza with foldable, individually controllable membrane strips that expand and contract as V-shaped folding elements similar to an accordion. Each strip slides along a pair of metal cables stretched between the buildings. With 48438 ft² /4,500 m² surface of membrane area, this lightweight structure provides shade during the day and can be opened at night so that the space then releases heat in the best possible way.
Special thermal comfort was required for particular areas called "cool pools", arranged at ground level around the square. A two-meter-high parapet surrounds them as protection from the frequent warm winds. Radiant cooling in the floor and supply of cooled circulating air leads to comfortable conditions. To ensure that the perceived temperature remains below 90°F / 32°C as often as possible up to seating height, i.e. 1.2 m above ground, the space is shaded and the "cool pools" are each protected by additional low-e shading whose coating reflects the cool radiation. This is the only way to maintain the desired thermal comfort.
The simulations performed by Transsolar for the outdoor comfort were very detailed and modeled ambient and radiant temperatures combined with wind conditions. This allowed precise statements to be made about thermal comfort with temporal and spatial resolution, such as for selected locations on the square as well as "cool pools" of different locations. This significantly influenced the design, the choice of materials for the "cool pools", the square and the openable roof.
Transsolar performed on-site measurements to verify the functionality of the cooling. Measurements were taken in several areas and at different positions of the "Cool Pools" and data for air temperature, relative humidity, ambient temperature (mean radiant temperature) and air velocity were recorded and used to calculate the perceived temperature (PT) based on the German guideline VDI 3787. This has verified that the requirements defined from the simulations are met, thus achieving the desired thermal comfort.
The local District Cooling Grid, a network that provides cooling for the entire district, also supplies the "cool pools."
