Experimental assessment of different mixing air ventilation systems on ventilation performance and exposure to exhaled contaminants in hospital rooms

• Published in: Energy and buildings 2018-10, Vol.177, p.207-219
• Main Authors: Berlanga, F.A., Olmedo, I., de Adana, M. Ruiz, Villafruela, J.M., José, J.F. San, Castro, F.
• Format: Article
• Language: English
• Subjects: Air conditioning; Airborne particulates; Airborne transmission of diseases; Ceilings; Configurations; Contaminants; Diffusers; Exposure; Grilles; Hospital room; Hospitals; Human exposure; Mixing ventilation; Occupational exposure; Personal exposure; Thermal comfort; Ventilation; Ventilation effectiveness thermal comfort
• ISSN: 0378-7788; 1872-6178
• DOI: 10.1016/j.enbuild.2018.07.053

•Airflow patterns generated by different mixing ventilation (MV) configurations influence performance and exhaled contaminants distribution in hospital rooms using mixing ventilation strategies.•The exposure to exhaled contaminants is a transient process in which punctual high peak values could be several times higher than the average.•There is an influence between the ventilation configuration and air renovation rate on the mean and peak exposure to exhaled contaminants.•The performance of MV configurations based on ceiling swirl diffusers are more reliable and less dependent on local airflow patterns.•The comparison between the results obtained for MV and displacement (DV) ventilation strategies highlight the good performance of DV for hospital room environments. This study evaluates the convenience of the use of four different mixing ventilation configurations in individual hospital rooms (IHR) based on ventilation performance and health workers (HW) exposure to the contaminants released by a confined patient (CP). Two supply configurations: grilles in the upper part of a wall (G) and swirl ceiling diffusers (S), combined with two different exhaust grilles positions in the opposite wall: upper part (U) and lower part (D) are tested using typical IHR set up. Occupants are represented by thermal breathing manikins, CP lies on a bed while HW stands close to it. Three air renewal rates are tested to determine their influence in the studied variables, 6, 9 and 12 ACH covering the whole range of ventilation requirements of such spaces. The experimental conditions considering the thermal comfort of the occupants are taken into account. Different ventilation configurations create different air distribution patterns inside the room. G configurations lead to high HW transient exposure values while S maintain low values that decrease when ACH is increased, so this second configuration is preferred for IHRs. Results are also compared with a displacement ventilation (DV) study highlighting the convenience of this strategy for IHRs. [Display omitted]