Particle loading rates for HVAC filters, heat exchangers, and ducts.

UNLABELLED The rate at which airborne particulate matter deposits onto heating, ventilation, and air-conditioning (HVAC) components is important from both indoor air quality (IAQ) and energy perspectives. This modeling study predicts size-resolved particle mass loading rates for residential and commercial filters, heat exchangers (i.e. coils), and supply and return ducts. A parametric analysis evaluated the impact of different outdoor particle distributions, indoor emission sources, HVAC airflows, filtration efficiencies, coils, and duct system complexities. The median predicted residential and commercial loading rates were 2.97 and 130 g/m(2) month for the filter loading rates, 0.756 and 4.35 g/m(2) month for the coil loading rates, 0.0051 and 1.00 g/month for the supply duct loading rates, and 0.262 g/month for the commercial return duct loading rates. Loading rates are more dependent on outdoor particle distributions, indoor sources, HVAC operation strategy, and filtration than other considered parameters. The results presented herein, once validated, can be used to estimate filter changing and coil cleaning schedules, energy implications of filter and coil loading, and IAQ impacts associated with deposited particles. PRACTICAL IMPLICATIONS The results in this paper suggest important factors that lead to particle deposition on HVAC components in residential and commercial buildings. This knowledge informs the development and comparison of control strategies to limit particle deposition. The predicted mass loading rates allow for the assessment of pressure drop and indoor air quality consequences that result from particle mass loading onto HVAC system components.

[1]  Stuart Batterman,et al.  HVAC Systems As Emission Sources Affecting Indoor Air Quality: A Critical Review , 1995 .

[2]  Jeffrey A Siegel,et al.  An evaluation of the indoor air quality in bars before and after a smoking ban in Austin, Texas , 2007, Journal of Exposure Science and Environmental Epidemiology.

[3]  Jae-Keun Lee,et al.  Characteristics of Air-Side Particulate Fouling Materials in Finned-Tube Heat Exchangers of Air Conditioners , 2005 .

[4]  William W. Nazaroff,et al.  Predicting particle deposition on HVAC heat exchangers , 2003 .

[5]  Tracy L. Thatcher,et al.  Deposition, resuspension, and penetration of particles within a residence , 1995 .

[6]  Jeff Haberl,et al.  The Effect of Reduced Evaporator Air Flow on the Performance of a Residential Central Air Conditioner , 1992 .

[7]  W. Fisk,et al.  Performance and costs of particle air filtration technologies. , 2002, Indoor air.

[8]  P. Hugenholtz,et al.  Heterotrophic bacteria in an air-handling system , 1992, Applied and environmental microbiology.

[9]  G Clausen,et al.  Initial studies of oxidation processes on filter surfaces and their impact on perceived air quality. , 2006, Indoor air.

[10]  B. C. Krafthefer,et al.  Energy use implications of methods to maintain heat exchanger coil cleanliness , 1986 .

[11]  William W. Nazaroff,et al.  Environmental Tobacco Smoke Particles , 2006 .

[12]  Jennifer A. McWilliams,et al.  Comparison between predicted duct effectiveness from proposed ASHRAE Standard 152P and measured field data for residential forced air cooling systems , 2002 .

[13]  P J Catalano,et al.  Using time- and size-resolved particulate data to quantify indoor penetration and deposition behavior. , 2001, Environmental science & technology.

[14]  William W. Nazaroff,et al.  Experiments Measuring Particle Deposition from Fully Developed Turbulent Flow in Ventilation Ducts , 2004 .

[15]  James E. Braun,et al.  The Role of Filtration in Maintaining Clean Heat Exchanger Coils , 2004 .

[16]  Lance Wallace,et al.  Continuous Monitoring of Ultrafine, Fine, and Coarse Particles in a Residence for 18 Months in 1999-2000 , 2002, Journal of the Air & Waste Management Association.

[17]  Gabriel Bekö,et al.  Ultra-fine particles as indicators of the generation of oxidized products on the surface of used air filters , 2005 .

[18]  Bin Zhao,et al.  Modeling particle deposition onto rough walls in ventilation duct , 2006 .

[19]  Pertti Pasanen,et al.  Reactions of Ozone on Ventilation Filters , 2003 .

[20]  William W. Nazaroff,et al.  Determining Size-Specific Emission Factors for Environmental Tobacco Smoke Particles , 2003 .

[21]  J. Siegel,et al.  Modeling Filter Bypass: Impact on Filter Efficiency , 2004 .

[22]  Ross D. Montgomery,et al.  Study Verifies Coil Cleaning Saves Energy , 2006 .

[23]  William W. Nazaroff,et al.  Modeling particle loss in ventilation ducts , 2003 .

[24]  Bin Zhao,et al.  Modeling particle deposition from fully developed turbulent flow in ventilation duct , 2006 .

[25]  David S. Ensor,et al.  Fractional Aerosol Filtration Efficiency of In‐Duct Ventilation Air Cleaners , 1994 .

[26]  D. B. Shirey,et al.  Impact of evaporator coil airflow in residential air-conditioning systems , 1997 .

[27]  Thomas E McKone,et al.  Indoor particulate matter of outdoor origin: importance of size-dependent removal mechanisms. , 2002, Environmental science & technology.

[28]  Jeffrey A. Siegel,et al.  Ozone removal by HVAC filters , 2007 .

[29]  Cynthia Howard-Reed,et al.  Source strengths of ultrafine and fine particles due to cooking with a gas stove. , 2004, Environmental science & technology.

[30]  William W. Nazaroff,et al.  Particle Deposition in Ventilation Ducts: Connectors, Bends and Developing Turbulent Flow , 2005 .

[31]  M. L. Laucks,et al.  Aerosol Technology Properties, Behavior, and Measurement of Airborne Particles , 2000 .

[32]  R. H. Braun.  Problem and solution to plugging of a finned-tube cooling coil in an air handler , 1986 .

[33]  De-Ling Liu,et al.  Modeling pollutant penetration across building envelopes , 2001 .

[34]  U. Bonne,et al.  Air-conditioning and heat pump operating cost savings by maintining coil cleanliness , 1987 .

[35]  Ruprecht Jaenicke,et al.  Chapter 1 Tropospheric Aerosols , 1993 .