Thermal comfort conditions are provided by a primary air (distributed by means of a displacement ventilation system) + radiant ceiling system. This combination minimises electricity consumption in pumps and fans. Light weight radiant ceilings allow for lower air temperature in winter and higher in summer, thus reducing energy consumption; moreover, the presence sensors, coupled with CO2 sensors, can modulate either the air flow and the ceiling temperature when few or no people are in the room, thus avoiding useless energy consumption. In summer night cooling takes place.

1.2.1 Tri-generation system

Gas engines are the core of the energy system of the building. They are connected to electric generators to produce most of the electricity required. The engines waste heat is used for heating in winter, for cooling — by means of absorption chillers — in summer and for hot water production all year round. Since in China presently is not allowed to sell electricity to the grid, the system is controlled in such a way that neither the electricity production exceeds the building’s demand nor the waste heat produced exceeds the heating or cooling demand. This means that sometimes, when thermal loads are low, electricity production is not sufficient and some power has to be taken from the grid. Some other times the cooling loads — that are higher than the heating ones — are so high that too much electricity would be produced; in this case, the excess electricity is diverted to compression chillers, slightly reducing, at the same time, the power of the engines. A sophisticated, "intelligent” control system manages the plant.

Because of the cleaner electricity produced, the amount of CO2 emissions per square meter of the SIEEB will be far lower than in present Chinese commercial building stock.