McDiarmid (1988) in "A Qualitative Evaluation of Air Distribution is Full-Scale Mock-Ups of Animal Holding Rooms," describes direct ventilation of animal cages in a research facility.
Effectiveness was defined as uniformity of airspeed among the 16 cages, airspeed being measured at the front face of each cage. This measurement plane was chosen since it represents the interface between the cage and the environment at which air exchange is free to occur through the cage grille. In so defining the design objective, the design scope was limited to providing a high quality environment around the cages. Determination of air quality inside occupied cages would be a complex undertaking beyond the scope of this design problem.
A high velocity airstream flows from the supply diffuser across the top of the room to the far wall. Near the far wall the air turns and flows downward in a 2- to 3 foot wide stream. Some air flows out the exhaust register and the rest of the stream flows back along the aisle floor and rises uniformly to be entrained in the high velocity stream. Another advantage of [the] scheme...is that it does not blow air out the doorway when the door is opened and thus helps to maintain room isolation.
Memarzadeh (1999) in a CFD study of animal rooms with cages indicates that ceiling or high-level exhausts tend to produce lower room temperatures when compared to low-level exhausts. In addition low-level exhausts appear to ventilate cages slightly better than ceiling or high-level exhausts when the cages are placed parallel to the walls. [Memarzadeh; 1999]
