Abstract
The requirements of laboratory facilities differ dramatically from those of other buildings. As we expand our biocontainment needs to Biosafety Levels (BSL) -2, -3, and -4, a clear need exists for an air quality and thermal comfort initiative targeting these facilities. The thermal comfort of occupants in laboratories can be controlled by the choice of ventilation strategy. Added benefits are the realization of a significant energy savings and improved indoor air quality. This study employs an advanced numerical simulation and empirical validation to assess the performance of active chilled beams in a general laboratory layout having some equipment intensive areas. The study examines the removal effectiveness of gases and airborne particles in such a system. Chilled beam performance is also compared to a ceiling diffuser system with and without cooling panels. The results of this study show that chilled beams improve thermal comfort and can be operated at reduced Air Changes per Hour (ACH) while maintaining a comfortable environment in occupied zones expressed as the Predicted Percentage Dissatisfied (PPD). To obtain a similar level of thermal comfort, a higher ACH is required in a ceiling diffuser system with cooling panels and bench exhausts. The chilled beam system also improves the removal effectiveness of gases or airborne particles because of the inherent better mixing in the room compared with the use of ceiling diffusers. In the cases studied, chilled beams have an insignificant effect on the fume hood containment. As satisfactory thermal comfort and air quality was achieved at a lower flow rate when compared with an all-air ceiling diffuser system, a savings of around 22% is estimated in annual energy costs for cooling and ventilating a typical lab in the Washington, DC area. The methodology and results of this study may be applied to further research for other laboratory types, or climatic conditions than those proposed in this study.