Description

Active chilled beams can provide energy efficient operation due to their hydronic sensible cooling, lower fan power requirements, and reduced reheat during low load or part load cooling conditions. Revision to ASHRAE Standard 170-2008 which allows recirculated air to be part of the total minimum air change rate requirements makes possible to employ active chilled beams in the patient rooms. Several inter-related factors can affect the performance of active chilled beam systems including the location and orientation of active chilled beams, supply air flow rates (air change rates), associated induction air flow rates, and location and strength of various heat sources in the patient rooms. This paper with the help of Computational Fluid Dynamics (CFD) analyses compares the performance of traditional overhead system with the active chilled beams and evaluates the impact of chilled beam orientation on the airflow patterns, temperature distribution, and resulting thermal comfort of occupants and on the probable flow path of airborne pathogens in a patient room. These analyses indicate active chilled beam systems can provide comparable airflow patterns, temperature distribution, and thermal comfort of occupants in the patient rooms. In both the systems, due to inductive nature of the airflow patterns, the airborne particles released from the patient’s face can get entrained back into the supply air stream and can eventually spread into the entire room. However placing a 1-way chilled beam over the patient’s head show a promise of providing cleaner environment with reduction in the recirculation and entrainment of airborne particles back into the supply air stream. It is noted that CFD can be an effective tool for analyzing and optimizing the design of air distribution systems to obtain the desired combination of occupant thermal comfort and the best possible hygienic conditions in patient rooms.

Citation: ASHRAE Papers: 2015 ASHRAE Annual Conference, Chicago, IL

Product Details

Published:

2015

Number of Pages:

8

File Size:

1 file , 2.6 MB

Product Code(s):

D-CH-15-C016