Air distribution through fan coil and displacement systems

Abstract

The air conditioning of indoor environments requires compliance with the thermo-hygrometric conditions of comfort which also includes the air distribution. This work deals with the thermo-fluid dynamics of the main components of air-conditioning systems, namely primary air systems with fan coils and displacement systems examined in winter and summer conditions. The study highlights the problems of each typology and identifies some best plant solutions. The air distribution systems by means of fan coils allow to reach thermal comfort even at very low speeds, which results also in reduced noise in the environment. The displacement system allows to work with lower air mass flow rate especially in summer cooling (the reduction is around 60%), whereas slightly different situation occurs in winter conditions. It has been found that it is possible to obtain a flow rate reduction of about 50% by combining together heating and cooling, with a considerable energy savings. The paper shows also that further advantages of the displacement systems compared to an all-Air system, has to do with the air velocity values in the occupied space.