China
Africa
Explore chapters and articles related to this topic
Room Air Distribution and Hybrid Secondary Systems
Published in T. Agami Reddy, Jan F. Kreider, Peter S. Curtiss, Ari Rabl, Heating and Cooling of Buildings, 2016
T. Agami Reddy, Jan F. Kreider, Peter S. Curtiss, Ari Rabl
The DOAS unit discussed earlier only conditions the OA and meets the latent loads of the space. The balance of the sensible loads of the spaces must be met by a separate cooling system. One such system is shown in Figure 20.28. Here, the same chiller or a separate chiller supplies the cold water for the radiant panels placed in the room. There are numerous other choices, for example, a parallel VAV system without airside economizer (for simplicity), packaged unitary heat pump system, fan coil units, ceiling radiant panels, chilled beams (with high aspiration rates—as high as 1:36—available commercially so as to meet the desired ADPI), and evaporative cooling and desiccant cooling systems. Further, one could use any of the three types of room air distribution systems: fully mixed, UFAD, or displacement ventilation.
Integrating IAQ control strategies to reduce the risk of asymptomatic SARS CoV-2 infections in classrooms and open plan offices
Published in Science and Technology for the Built Environment, 2020
Good room air distribution is essential to deliver the fresh air to the breathing zone, avoid the cross-infection in the room, and remove the pollutants. This is an area so far has been largely neglected in existing guidelines or recommended practices for reducing the SARS CoV-2 virus infection. Most classrooms and open plan offices in the U.S. use “mixing ventilation (MV)” for fresh air delivery. Air diffusers in MV are typically located close to the ceiling level to discharge air jets at high enough velocity for sufficient mixing with the existing room air before reaching the occupied zone. If such a system is set or modified to operate at 100% outdoor air when possible as recommended by ASHRAE (2020), attention should be paid to make sure that there is sufficient airflow rate through the air diffuser to create enough mixing and prevent short circuiting of the air from the supply to the exhaust.