Comparison of room airflow characteristics in a full scale environment chamber with cold air distribution.

This paper discusses the experimental study of direct delivery of cold air into a full scale environmental chamber using different diffusers, i.e. a multi-cone circular ceiling diffuser, a vortex diffuser and a nozzle type diffuser. Comparisons have been made of the following: mean flow patterns, temperature distribution and condensation risk. The vortex diffuser exhibits a higher induction effect than that of the nozzle type diffuser. However, the air speed generated by the vortex diffuser is generally lower than that of nozzle type diffuser. Both the vortex diffuser and the nozzle type diffuser can be considered to have condensation-free characteristics, although some vapor film was observed in the early stage of a "hard start up" test for the nozzle type diffuser.