for decreased exposure risk indoors Arsen K. Melikov Workplace and Indoor Aerosols, April , Lund

Transcription

1 Emerging technologies for decreased exposure risk indoors Arsen K. Melikov Workplace and Indoor Aerosols, April , Lund International Centre for Indoor Environment and Energy Department of Civil Engineering, Technical University of Denmark 1 In industrialized countries people spend more than 90% of the time confined spaces Decrease of exposure to indoor aerosols (including bio-aerosols) is important 2 1

2 Decrease of exposure to indoor aerosols Source control Ventilation (air distribution) Supply air cleaning (filtration, UVGI, etc.) In room cleaning (air purifiers, UVGI, etc.) Ventilation and Sick Leave Fisk et al

3 Total Volume Air Distribution Mixing air distribution Displacement air distribution Present air distribution is inefficient! Entire (including unoccupied) space is ventilated Large airflow rate is supplied (energy, space, cost!) People do not breath clean air (supplied far away!) 5 Energy Saving Policy Response: Decrease? of ventilation rate! Result: increased exposure negative impact on occupants health decrease of work performance enormous societal losses Solution: Creating Shared Value by responding to both societal & economic needs How to do it? New approach of indoor environmental design by advanced air distribution 3

4 Advanced Air Distribution (AAD) Personalized ventilation (PV) Supply of clean and conditioned air: When it is needed Where it is needed As much as needed Melikov, Indoor Air, 2004 AAD: Airflow Interaction Control ate Univ., USA G.Settels, Pensta Control of personalized flow (Nastase & Meslem, J. of Visualization, 2008) 30% 90% 90% Portion of clean air in inhaled air 8 (Bolashikov, Melikov, Kranek, HVAC Transactions, 2009) 4

5 Advanced Air Distribution in Offices Documented improvement of: health (SBS symptoms, etc.) thermal comfort perceived air quality performance (Kaczmarczyk, Melikov, IA 2004, BAE 2012) Predicted energy saving up to 50% due to: control of outdoor air supply occupant density keeping room temperature high & local cooling (Schiavon, Melikov, Energy & Building, 2010) 9 Airborne Transmission of Viruses Sneezing, coughing, talking Droplets ( m) with viruses settling, evaporation, inhalation Breathing - Exhalation Airborne aerosols (< 1 m) with attached viruses (0.003 to 0.06 m) Inhaled by occupants 10 5

6 Air Distribution and Cross-Infection R A0 - reproductive number of secondary infections that arise when a single infectious case is introduced into a population where everyone is susceptible [Rudnick and Milton, Indoor Air, 2003] Reprod ductive number Mixing Influenza PV 10 L/s per person 40 L/s per person Transmission likely unlikely Cermak Cermak & Melikov, and Melikov B&E Protection against cross-infection Medium cough (DP 12 μm); t=5 s Medium cough (DP 12 μm); ACS at 16 L/s; t=5 s Majei

7 Advanced Air Distribution in Hospitals HBIVCU Method The cleansed filtered air is moved upwards creating two air curtains and/or a horizontal air curtain preventing airborne spread of pathogens among patients and health care staff Exhaust Cleansed air Sensors Polluted air 13 DTU Patent Application,EP & US 61/226,542 HBIVCU Performance: CFD Predictions CP EP CP EP 14 7

8 HBIVCU Performance: Experiment Breathing and coughing full size thermal manikins used to resemble patients and doctor Exhaled/coughed air by the sick person marked with tracer gas Tracer gas measured in the air inhaled by the exposed person 15 HBIVCU Performance: Experiment 1- Source patient (Coughing dummy); 2 - Doctor (breathing thermal manikin); 3 - Exposed patient (breathing thermal manikin); 4 - Exhaust; 5 - HBIVCB Mixing Ventilation: 3,6,12 ACH; Room temperature: 22 C 16 Coughing & Breathing patient: lying on side & back 8

9 HBIVCU Performance: Experiment Melikov et al. Idoor Air 2011 Evacuation efficiency is defined as tracer gas concentration at exhaust without HBIVCU at 3 ACH devided by tracer gas concentration at measured point with or without the HBIVCU. 17 Performance of HBIVCU: Coughing Doctor: 0.55 m from coughing patient lying on side Melikov et al. IFHE,

10 Advanced Air Distribution: Seat Headrest PV Part of the study reported in Melikov et al., B&E, 2012 Advanced Air Distribution Seat headrest PV: Control of airflow interaction 20 10

11 Advanced Air Distribution Airsonett 21 Bolashikov et al., HVAC & Research, 2010 Advanced Air Distribution: Vehicle Cabin 11

12 Advanced Air Distribution: Aircraft Cabin Ventilation Background: 180 L/s PV supply: 10 L/s PV exhaust: 10 L/s Melikov & Dzhartov, HB2012, 2012 Advanced Air Distribution: Aircraft Cabin RIC=Ce/Ce,off - Relative tracer gas concentration in inhaled air Ce - Concentration of tracer gas exhaled by the infected passenger in the air inhaled by the exposed passenger Ce,off is Ce when suction and PV are off 24 Background: 180 L/s; PV supply: 10 L/s; Suction: 10 L/s 12

13 Advanced Air Distribution: Headset PV Zhu et al. Indoor Air, 2008 To be published 25 Advanced Heating, Cooling & Ventilation (AHCV) Natural Ventilation & AHCV Protection of Staff Hospital Indoor Environment Quick healing of patients Increased performance of staff Decrease hospital acquired infections Energy saving 26 13

14 Advanced Air Distribution Decreased exposure in bedroom Airsonett Clean air for improved quality of sleep 27 Thank you! 28 14

15 List of Publications referred in the presentation: Fisk, W.J., Seppänen, O., Faulkner, D. and Huang J., 2003, Cost benefit analysis of ventilation control strategies in an office building, Proceedings of Healthy Buildings 2003 Conference. Singapore, December Vol. 3, pp Melikov, A.K., 2004, Personalized ventilation, Indoor Air, vol. 14, supplement 7, pp Nastase, I. and A. Meslem, 2008, Vortex dynamics and entrainment mechanisms in low Reynolds orifice jets, Journal of Visualization, (4). Bolashikov, Z.D., Melikov A.K., Kranek, M., 2009, Improved Performance of Personalized Ventilation by Control of the Convection Flow around an Occupant s Body, ASHRAE Transactions, vol. 115, Part 2. Kaczmarczyk J., Melikov A., Fanger, P.O, 2004, Human response to personalized and mixing ventilation, Indoor Air, 14 (suppl.8), Melikov, A.K.and Kaczmarczyk, J Air movementand perceived air quality, Building and Environment, 47, pp DOI: /j.buildenv Schiavon, S., Melikov, A.K., Sekhar, C., 2010, Energy analyses of the personalized ventilation system in hot and humid climates, Energy and Buildings, vol. 42, pp Rudnick, S.N. and D.K. Milton, 2003, Risk of Indoor Airborne Infection Transmission Estimated from Carbon Dioxide Concentration, Indoor Air 13, pp List of Publications referred in the presentation: Cermak, R. and Melikov, A., 2007, Protection of occupants from exhaled infectious agents and floor material emissions in rooms with personalized and underfloor ventilation, HVAC&R Research, vol. 13, no. 1, pp Mitja Mazej, Local ventilation for controlling airborne cross infection in spaces, Faculty of Mechanical Engineering, University of Ljubljana, Ljubljana, Slovenia, PhD Theses, DTU Patent Application. Device and method for reducing spread of microorganisms and airborne health hazardous matter and/or for protection from microorganisms and airborne health hazardous matter (in process of patenting EP and US 61/226,542). Melikov, A., Bolashikov, Z., Georgiev, E Novel ventilation strategy for reducing the risk of airborne cross infection in hospital rooms. In: Proceedings of Indoor Air 2011, University of Austin, paper Melikov, A., Bolashikov, Z., Brand, M., 2010, Experimental investigation of performance of a novel ventilation method for hospital patient rooms, Proceedings of the 21st Congress of International Federation of Hospital Engineering (IFHE), Tokyo Japan, November 17 th to 19 th, Melikov, A.K., Ivanova, T., Stefanova, G Seat Headrest Incorporated Personalized Ventilation: Thermal comfort and Inhaled Air Quality, Building and Environment, 47, pp

16 List of Publications referred in the presentation: Bolashikov, Z.D., Melikov A.K., Kranek, M., 2010, Control of the Free Convective Flow around the Human Body for Enhanced Inhaled Air Quality: Application to a Seat Incorporated Personalized Ventilation Unit, HVAC&R Research, vol.16, no. 2, pp Melikov, A.K. and Dzhartov, V Advanced air distribution for minimizing airborne cross infection in aircraft cabin, Proceedings of Healthy Building 2012, July 8 12, Brisbane, Australia Zhu, S., Bolashikov, Z., Melikov, A., 2008, Examination of performance of headset incorporated personalized ventilation unit using CFD method, Proceedings of the 11 th International conference on Indoor Air Quality and Climate Indoor Air 2008, August 2008, Copenhagen, Paper ID: