http://en.wikipedia.org/wiki/Displacement_ven...:
"Displacement ventilation is an room air distribution strategy where cool and clean air is supplied at floor level and extracted above the occupied zone, usually at ceiling height."
Mundt, E.; Nielsen, P. V.; Hagström, K. & Railio, J. Skistad, H. (Ed.) "REHVA Guidebook No. 1 - Displacement Ventilation in Non-industrial Premises" REHVA Federation of European Heating, Ventilation and Air-conditioning Associations, 2004, 106 p.:
"Displacement Ventilation: Room ventilation created by room air displacement, by introducing air at low level in a space at lower temperature than the room air."