A glass envelope acting as a kind of biodome encapsulates four mixed-use towers at Parkview Green FangCaoDi, an 800,000 sf mixed-use development in Beijing. The glass structure helped the development to achieve LEED Platinum certification. The glass envelope acts as a buffer that helps reduce heating in the winter and protects the interior against the summer heat. Specially designed louvers at the top allow hot air to escape and natural ventilation and free cooling modes to be operated when outdoor condition is desirable.