Case Study: Prestigious Event Center Achieves Sustainability Goals Using the Indoor Air Quality Procedure of ASHRAE 62.1.
The Shelby Farms Park Retreat Center is part of a large expansion of the Shelby Farms Park Conservancy "Heart of the Park" project, located in Memphis, TN. Heart of the Park is designed to be a vibrant and diverse community hub, an environmental teaching tool, an important part of the business plan to sustain the Park, a gathering place for health and recreation, relaxation and big water adventure.
The Center is a one-story building, having a project area of 10,000 square feet (100,000 square meters). The center includes events spaces, offices, breakout rooms, lobby, and storage room. The mechanical system for the center features a geothermal loop which runs horizontally across the bottom of the adjacent lake bed. The loop serves as a heat sink and source for the water source heat pumps inside the building which increases their efficiency. This is the first structure in Shelby County, TN to be heated and cooled by geothermal energy obtained using these methods. There are 10 heat pumps (HP) providing heating, cooling, and ventilation for the retreat center which are each zoned individually. The zones for HP-2, 4, 8, and 9 are the ones that experience the largest loads due periodic high occupancy levels in the large "Events 112" space that they serve. Figure 1 shows the zones and square footage served by the heat pumps (labeled as HP). The original plan called for the use of geothermal wells to meet all the cooling and heating load, including the load from outside air. However, the total requirements of the wells to meet the outside air requirements was prohibitive within the construction project, threatening the completion of the project and meeting the goal of a state-of-the-art sustainable event center for all the community.
To solve this problem the engineers used the indoor air quality procedure (ASHRAE IAQP and LEED Pilot Alternative Compliance Path 68: Indoor Air Quality Procedure) to susbtitue part of ventilation with air cleaning and therefore decrease the load experienced by these heat pumps. Explanation and application of this procedure has been published in various literature studies (Stanke, 2010; Grimsrud, Bridges et al., 1999; Stanley and Lamping 2008; Grimsrud, Carlson et al., 2011; Dutton, Chan et al., 2013; Zaatari et al., 2016).
Four air cleaning modules have been specified. Each of these air cleaning modules is composed of sorbent materials housed in proprietary cartridges that are engineered to capture carbon dioxide (C[O.sub.2]), aldehydes, volatile organic compounds (VOCs), [PM.sub.2.5] and inorganics, a heating element for regeneration, two small fans for regeneration and adsorption, and a set of sensors measuring temperature, relative humidity, carbon dioxide and volatile organic compounds of return, supply, treated and regenerated air. The air cleaning system interprets the output of these sensors using control algorithms to actively and automatically manage HVAC load and indoor air quality.
Although the air cleaning modules are ducted to the different spaces, the entire floor shares a common return (the return from the different spaces is not ducted). The areas not served by the air cleaning modules are supplied with the outdoor air flow rate according to the conventional design (ventilation rate procedure; ASHRAE Standard 62.1-2016).
Table 1 shows the air cleaning number ducted to the space and outside air cfm for the different zones. As shown below, by incorporating the air cleaning modules, the total outside air required for these zones equals to 1,190 CFM (2,021 [m.sup.3]/hr). The original design called for 4,000 CFM (6,800 [m.sup.3]/hr).
The main objective of this study is to present energy savings nd exposure benefits (measured contaminants concentrations and surveys) of applying the IAQP.
IAQP MEASUREMENT AND METHODS
Objective and subjective demonstration were performed at the center when an event occurred (event area was at maximum capacity).
The investigation included full speciation of VOCs, aldehydes (formaldehyde and acetaldehyde), C[O.sub.2]], CO, PM2.5 and ozone. Detailed IAQ measurements were taken in five test locations -1+2 (combined), 3, 4 5 and 6--shown in Figure 2 below. Test locations 1 and 2 were combined due to lack of physical place to locate two sampling events.
The instruments used for each type of measurement and the manufacturer-reported detection principle, resolution, and uncertainty are summarized in Table 2.
Technologies sorbent tubes and pumps. For one of the samples, we collected one duplicate sample and one field blank sample. Approximately 6 liters were drawn through each sampling tube for a duration of 30 minutes. Pump flow rate was checked before and after the sampling using a flow calibrator. Continuous formaldehyde concentrations were also measured using the continuous sensor. The continuous sensor was collocated with the sorbent tube to obtain a calibration factor. Hence the output of this continuous sensor should be considered accurate.
Technical information about formaldehyde analysis by the certified Lab: all the formaldehyde methods listed use the same analysis technology, DNPH (2,4-Dinitrophenylhydrazine) coated cartridges that derivatize the analytes followed by analysis using HPLC with UV detection. The lab that we used uses a different method based on the reaction of formaldehyde with acetyl-acetone (2,4-pentadione) and ammonia which produces the derivative 3,5-diacetyl-1, 4-dihydrolutidine (DDL) followed by fluorescence detection. This reaction is achieved automatically using an Aero-Laser (AL4021) formaldehyde gas analyzer which can detect formaldehyde in air down to <1 ppb and has extremely minor interferences, making it a reliable and stable method for determining formaldehyde. Although not as common in the US as the DNPH methods, it's widely used in Europe and has been compared with DNPH results with good agreement.
TVOC and speciated VOCs (including acetaldehyde) were measured using third party lab sorbent tubes and pumps. For one of the samples, we collected one duplicate sample and one field blank sample. For baseline measurements, approximately 24 liters were drawn through each sampling tube for a duration of 2 hours. Pump flow rate was checked before and after the sampling using a flow calibrator. Technical information about TVOC analysis by the certified lab: TVOC is determined using the chromatographic area of the sample minus the chromatographic area of the laboratory blank converted to concentration using the average chromatographic area of three internal/surrogate standards (1,4-difluorobenzene, toluene-d8, and chlorobenzene-d5). Very volatile (e.g., C3 and C4) compounds/chromatographic areas are not included. This is similar to the procedure outlined in ISO method 16000-6.
In addition to IAQ measurements, we distributed via web-application a seven-point scale questionnaire to building occupants that work in the center to evaluate their satisfaction of the indoor air quality.
The use of the air cleaning modules made it possible to downsize the system tonnage. The capital expense savings due to the air cleaning technology is estimated to be $90,000; which is equivalent to drilling 30 tons of vertical wells at a cost per ton of $3,000.
IAQ Objective Demonstration
As described in IAQ Measurement and Methods, concentrations of COCs were measured after the air cleaning modules had been installed and during an event with the maximum occupancy.
C[O.sub.2], CO, ozone, [PM.sub.2.5] were also measured in each location as shown in Figure 2. In addition, C[O.sub.2] and [PM.sub.2.5] were also measured outdoors. All measurements were below the LEED targets. As expected, CO and ozone showed zero concentrations due to absence of outdoor/indoor sources.
C[O.sub.2] varied between 465 ppm to 982 ppm among all locations. The event area exhibited the higher C[O.sub.2] value measured. Event started at 6 and ended at 10. The air cleaning system was optimized to keep C[O.sub.2] below the 1100 ppm threshold, as the air cleaning system removes carbon dioxide.
PM results were generally suggestive of relatively clean environments when compared to investigations of other building types (restaurants: Bennett et al., 2011; Brown et al., 2012; Buonanno et al., 2010, residences: Wallace et al., 2004, classrooms: Branis et al., 2005; offices: Burton et al., 2000) and ambient/occupational regulatory limits. [PM.sub.2.5] indoors and outdoors concentrations were low (lower than 10 ug/[m.sup.3]). This was expected as no cooking activities happened on site and the area of the site can be classified as a rural area. A spike was observed around 9:16 to 9:32. During this time, dancing activities took place.
Speciated VOCs and aldehydes were also measured in each location as shown in Figure 2. All measured VOCs and formaldehyde were far below their established limits. Table 3 displays top 10 VOCs including formaldehyde and acetaldehyde concentrations measured in one of the locations.
Comparing these findings to published studies, the measured speciated VOC concentrations were lower compared to the results reported in the BASE (building assessment survey and evaluation study involved 100 office buildings across the U.S.; Apte and Erdmann 2002), the RIOPA (the relationship of indoor, outdoor, and personal air study was conducted in 100 residences from 1999 to 2001 in three American cities; Weisel et al. 2005), and Logue et al. 2011 (reviewed 77 published studies that reported measurements of chemical pollutants in residences from 2001-2008; newer homes than in the RIOPA study) in the United States and in countries with similar lifestyles).
The survey was distributed to the employees at the center. The results show that 83% of the employees were very satisfied with the space and the rest were moderately satisfied.
LEED certification is in process at time of writing this paper. The LEED IAQP EQpc68 pilot credits can contribute up to 17 points in the following categories as shown in table 4:
The outcomes of this study showed that using the IAQP with air cleaning modules and minimum ventilation realized sustainability goals to the first geothermal center in the Shelby county. Air cleaning modules provided a healthy and comfortale environment for the employees and the visitors of the center.
The research was funded by enVerid Systems.
C[O.sub.2] = carbon dioxide
VOCs = volatile organic compounds
PM2.5 = particulate matter of diameter 2.5 [micro]m or less
IAQ = indoor air quality
VRP = ventilation rate procedure
IAQP = indoor air quality procedure
COCs = contaminants of concern
HP = heat pump
LEED = Leadership in Energy and Environment Design
Apte, M., and Erdmann, C. A. 2002. Indoor carbon dioxide concentrations and sick building syndrome symptoms in the BASE study revisited: Analyses of the 100 building dataset. Indoor Environment Department, Lawrence Berkeley National Laboratory, Berkeley, CA, LBNL-51570.
ASHRAE. 2016. ASHRAE Standard 62.1 Ventilation for Acceptable Indoor Air Quality. Atlanta: ASHRAE.
Bennett, D., Apte, M., Wu, X., Trout, A., Faulkner, D., and Sullivan, D. 2011. Indoor Environmental Quality and Heating, Ventilating, and Air Conditioning Survey of Small and Medium Size Commercial Buildings: Field Study. No. CEC-500-2011-043.
Branis M, Rezacova P, Domasova M. 2005. The effect of outdoor air and indoor human activity on mass concentrations of PM, PM, and PM in a classroom. Environmental Research, 99:143-149.
Brown, K. W., Sarnat, J. A., and Koutrakis, P. 2012. Concentrations of PM2.5 mass and components in residential and non-residential indoor microenvironments: The sources and composition of particulate exposures study. Journal of Exposure Science and Environmental Epidemiology, 22: 161-172.
Burton L.E, Girman J.G., Womble S.E. 2000. Airborne particulate matter within 100 randomly selected office buildings in the United States (BASE). In: Proceedings of Healthy Buildings. page 157-62.
Buonanno, G., Morawska, L., Stabile, L., and Viola, A. 2010. Exposure to particle number, surface area and PM concentrations in pizzerias. Atmospheric Environment, 44(32): 3963-3969.
Dutton, S. M., W. R. Chan, M. J. Mendell, M. Barrios, S. Parthasarathy, M. Sidheswaran, D. Sullivan, E. Eliseeva and W. J. Fisk (2013). Evaluation of the indoor air quality procedure for use in retail buildings. Berkeley, CA, Lawrence Berkeley National Laboratory Report. LBNL-6079E.
Grimsrud, D. T., N. Carlson, B. Bridges, T. Springman and S. Williams (2011). Investigation of appropriate ventilation rates for retail stores. Indoor Air 2011. Austin, TX. Paper 961.
Lamping, G. and C. O. Muller (2009). Air cleaning in practice - school sustainability results and commercial building field study results. Indoor Air Quality Association 2009 Conference, Indoor Air Quality Association.
Logue, J. M., McKone, T. E., Sherman, M. H., and Singer, B. C. 2011. Hazard assessment of chemical air contaminants measured in residences. Indoor Air, 21(2): 92-109.
Stanley, W. B. M. and G. Lamping (2008). Case study: applying the IAQ procedure with present technology at a high school facility. IAQ 2007 Healthy and Sustainable Buildings. Baltimore, MD, ASHRAE.
Stanke, D. 2012. Minimum outdoor airflow using the IAQ procedure. ASHRAE Journal 54(6): 27-34.
Wallace, L. A., Emmerich, S. J., and Howard-Reed, C. 2004. Source strengths of ultrafine and fine particles due to cooking with a gas stove. Environmental Science and Technology, 38(8): 2304-2311.
Weisel C.P., Zhang J.J., Turpin B.J., Morandi M.T., Colome S., Stock T.H., et al. 2005. Relationships of Indoor, Outdoor, and Personal Air (RIOPA) Part I. Collection Methods and Descriptive Analyses. Health Effects Institute.
Zaatari, M., Novoselac A., Siegel J. 2016. Impact of ventilation and filtration strategies on energy consumption and exposures in retail stores. Building and Environment. Volume 100. Pages 186-196
Marwa Zaatari, PhD
Table 1. Area and air cleaning modules specification Ducted Outside air air (designed with Area name cleaning [ft.sup.2] [[m.sup.]] air cleaning (Figure 1) modules module installed) number CFM [[m.sup.3]/hr] HP-9 unit 1 1800  210  HP-8 unit 2 1725  210  HP-7(A,B,C) unit 2 1296  140  HP-4 unit 4 1700  210  HP-2 unit 5 1810  210  Original outside air design (VRP) Area name Area (Figure 1) CFM [[m.sup.3]/hr] HP-9 916  Event area HP-8 911  Event area HP-7(A,B,C) 347  Breakout area HP-4 909  Event area HP-2 917  Event area Table 2. Measurement instruments used Pollutant Detection Principle Photoelectric Absorptiometric Formaldehyde Sorbent Tubes Integrated 30 mins TVOC Sorbent Tubes Integrated 2 hours PM2.5 Laser Particle Counter C[O.sub.2] Non-Dispersive Infrared CO Galvanic cell [O.sub.3] GSS Temperature Thermocouple Relative Humidity Thermo Hygrometer Pollutant Resolution 1 ppb (1.25 [micro]g/[m.sup.3]) Formaldehyde 4 ppb (5 [micro]g/[m.sup.3]) TVOC 200 [micro]g/[m.sup.3] PM2.5 1 #/[m.sup.3] (0.03/[ft.sup.3]) C[O.sub.2] 1 ppm CO 1 ppm [O.sub.3] 0.001 ppm Temperature 0.1[degrees]C (0.18 F) Relative Humidity 1% Pollutant Uncertainty [+ or -]4 ppb (5 [micro]g/m3) at <40 ppb (50 [micro]g/m3), [+ or -]10% of reading at >40 ppb (50 [micro]g/m3) Formaldehyde Test compliant with the California Air Resources Board's (CARB) [section] 93120, European DIN Standard EN-717, and ASTM methods D-5582 and E-1333 TVOC Test compliant with US EPA Compendium Method TO-17 PM2.5 Coincidence loss less than 10% at 3,000,000 C[O.sub.2] [+ or -]40 ppb (<1,000 ppm) [+ or -]5% (>1,000 ppm) CO [+ or -](5% + 2 ppm) From 0 - 0.1 ppm: [O.sub.3] <+/- 0.008 ppm From 0.1 - 0.5 ppm: +/- 10% Temperature [+ or -]0.3[degrees]C (0.54 F) Relative Humidity [+ or -]2%RH <80%RH ([+ or -]3%RH>80%RH) Table 3. Top 10 VOCs and aldehydes concentrations Concentration Compound Sample [micro]g/[m.sup.3] ppb Formaldehyde 14 11 Ethanol 480 250 Limonene 63 11 1-Methoxy-2-propanol 30 8 Acetone 28 12 Pentane (C 5) 23 8 Acetaldehyde 19 10 Isopropanol 12 4.8 m,p-Xylene 6.9 1.6 Toluene 5.6 1.5 Ethylbenzene 3.6 0.8 Table 4. Anticipated LEED points per different LEED categories O+M BD+C ID+C Energy 8 8 8 Indoor Environment Quality (IEQ) 6 Innovation 3 1 1 Total 17 9 9
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|Publication:||ASHRAE Conference Papers|
|Article Type:||Case study|
|Date:||Jan 1, 2018|
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