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Measurement and Verification Project Plan:Gaseous Air Cleaning Technologies
National Renewable Energy Laboratory
Golden CO
June 30, 2015
Internal Report Prepared for
Building Technologies Office
Office of Energy Efficiency and Renewable Energy
U.S. Department of Energy
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Nomenclature or List of AcronymsASHRAE American Society of Heating, Refrigerating and Air-Conditioning Engineers
CO2 carbon dioxide
DOE U.S. Department of Energy
HVAC heating, ventilation, and air conditioning
IAQ indoor air quality
IAQP Indoor Air Quality Procedure
IEQ indoor environmental quality
M&V measurement and verification
O&M operations and maintenance
ppb parts per billion
ppm parts per million
RH relative humidity
T temperature
TVOC total volatile organic compounds
VOC volatile organic compounds
VRP Ventilation Rate Procedure
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Table of Contents1 Introduction......................................................................................................................................... 12 Technology Description...................................................................................................................... 23 Demonstration Objectives.................................................................................................................. 34 Site Selection....................................................................................................................................... 55 Demonstration Design........................................................................................................................ 8
5.1 Monitoring Period..........................................................................................................................85.2 Baseline Energy Performance Determination................................................................................85.3 Baseline IAQ Determination..........................................................................................................85.4 Instrumentation and Monitoring.....................................................................................................9
6 Performance Analysis and Assessment..........................................................................................11References............................................................................................................................................... 13
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List of FiguresFigure 1. Typical installation of the air cleaning technology in the return air stream...................................2
List of TablesTable 1. Technology Performance Objectives, Metrics, and Data Requirements..........................................4Table 2. Site Information................................................................................................................................5Table 3. High-Level Criteria..........................................................................................................................6Table 4. Systems-Related Criteria..................................................................................................................7Table 5. Utilities-Related Criteria..................................................................................................................7Table 6. Continuous Performance Monitoring and Instrumentation..............................................................9Table 7. Short-Term Performance Monitoring and Instrumentation............................................................10
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1 IntroductionThis report provides a measurement and verification (M&V) plan for gaseous air cleaning technology used to clean a building’s return airstream. The intent is to scrub carbon dioxide (CO2) and other gaseous contaminants from the return air in order to reduce the outside air and the associated energy required to condition the outside air.
This plan provides information about:
The technology and how it is expected to reduce energy consumption
The demonstration objectives, technology performance objectives, technology performance metrics, and data requirements
The demonstration design, including the instrumentation required to enable data collection and performance evaluation
The analysis methods that will be used to estimate the performance.
The demonstration plan presents assumptions about the technology to be tested, demonstration objectives, and proposed M&V approaches. The demonstration plan should be customized for each technology and demonstration site.
This demonstration plan assumes that the outside air (OA) ventilation rate for acceptable indoor air quality (IAQ) is defined by ASHRAE Standard 62.1-2013, Ventilation for Acceptable Indoor Air Quality (ASHRAE 2013a). Standard 62.1 presents three methods to achieve compliance with the standard: the ventilation rate procedure (VRP), indoor air quality procedure (IAQP), and natural ventilation procedure. This demonstration plan assumes that the OA ventilation in the building before air cleaning system is set by the prescriptive VRP and that the IAQP is used is determine the reduction in OA ventilation rate with the air cleaning system. The natural ventilation procedure is not used in this demonstration plan. In addition, the Standard 62.1 requirements for exhaust ventilation must be met for all three methods.
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2 Technology Description The focus of this demonstration M&V project plan are air cleaning technologies that selectively removes gaseous contaminants from the return airstream with the goal of reducing the required OA ventilation requirements. It is assumed that the technology used for this demonstration plan uses a regenerable sorbent material to adsorb carbon dioxide (CO2) and volatile organic compounds (VOCs) from the air. The sorbent material absorbs the gaseous chemicals during sorption cycle and must have a regeneration cycle to eliminate the absorbed gases usually by heating the sorbent material and exhausting the gases. The energy consumed during the regeneration cycle must be lower than the energy saved by reducing the OA ventilation to save energy.
A typical installation in the return airstream near the air handling unit (AHU) is shown in Figure 1. During the air cleaning cycle, a portion of the return air is processed through the air cleaner and the OA damper is closed slightly to reduce the OA brought into the building. Reducing the amount of OA ventilation required can reduce HVAC loads and provide significant energy savings and peak demand reduction. In addition, there is a potential to improve the cooling systems ability to meet the latent cooling requirements in hot-humid climates because the outside air is the major source of humidity in a building. During the regeneration cycle, the dampers to the return airstream are closed and the regeneration airstream dampers are opened to purge the captured gases from the sorbent material.
Figure 1. Typical installation of the air cleaning technology in the return air stream
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3 Demonstration ObjectivesThe proposed objectives for this demonstration are divided into two technical and four deployment related objectives. The technical performance objectives are to:
1. Determine the energy performance and energy cost savings of operation with the air cleaning technology compared to baseline operation without the air cleaning technology.
2. Confirm that indoor environmental quality (IEQ) meets the requirements for air quality and thermal comfort defined in ASHRAE Standards 62.1 and 55 (ASHRAE 2013a, 2013b).
The deployment-related objectives are to:
1. Identify and document the technical and practical challenges that emerge in design, installation, control, and operation of the air cleaning system.
2. Document the level of occupant and maintenance staff satisfaction with the air cleaning system.
3. Estimate the economic performance of the air cleaning system.
4. Estimate the potential market impact and document potential challenges for wide-scale deployment.
Building on these objectives, Table 1 shows the general performance objectives, metrics, and data requirements for this technology demonstration. These requirements should be modified for each demonstration technology and site to accommodate demonstration specific details. Additional objectives may be added for each technology and site, depending on the needs of the building and the occupants. The specific indoor air contaminants of concern and performance targets should be determined in coordination with the subject matter experts for each project and the building owners to identify and measure occupant and maintenance staff satisfaction for each site. Close work with building owners will also be critical to make sure equipment receives proper attention and that operational issues impacting testing results are quickly resolved. Information from owners on O&M costs, work orders, and occupancy changes are important for evaluation. Owner support is also needed to conduct air quality monitoring particularly when the monitoring will be performed in occupied spaces during occupied hours.
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Table 1. Technology Performance Objectives, Metrics, and Data Requirements
Technology Performance
ObjectivePerformance
Metric(s)Preliminary
Performance Target Data Requirements
Maintain target CO2 levels
Indoor CO2 concentration in ppm
TBD (site specific)
Continuous measurements outdoor CO2 concentration and indoor CO2 concentrations in selected spaces and in the return air ducts
Maintain acceptable levels of specific contaminants of concern and contaminant mixtures of concern
TBD (site specific) TBD (site specific)
Continuous measurements of TVOCs and short-term measurements of specific contaminants
Maintain comfortable indoor temperature and relative humidity (T&RH)
T&RH Within Standard 55 comfort requirements T&RH from selected spaces
Reduce outside air requirements
Outside airflow rate TBD (site specific)
Outside airflow rates. Measure building pressurization to maintain positive.
Reduce energy consumption for treating outside air
Chiller, DX, or boiler energy consumption
TBD (site specific) Chiller, DX and boiler energy as required for each project
Reduce overall HVAC energy consumption
15-minute and daily HVAC energy consumption
TBD (site specific)
15-minute energy data for chillers, air handling unit fans, air cleaning technology fans and regeneration. 15-minute or daily data for boiler or furnace gas consumption. 15-minute ambient T&RH (for normalization of energy data)
Maintain occupant satisfaction
Occupant satisfaction with IAQ
> 80% satisfiedOccupant satisfaction survey during air cleaning system operation
Net annual decrease in HVAC related O&M costs
HVAC O&M costs No increase in O&M costs
HVAC O&M costs, chiller run time, energy costs
Determine the effective life of the sorbent material cartridges
Average replacement age 1 year Contaminant removal rates
measured every 3 months
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4 Site SelectionThe general strategy for selecting sites is based on the potential for energy savings. This technology has the potential for the greatest savings in extreme climates where large amounts of energy are required for heating or cooling and dehumidifying the outside air. Buildings with high ventilation loads such as schools, office buildings, assembly buildings, and retail buildings are good candidates. Ideal site candidates would have active building automation systems and sub metering which can be accessed remotely. Healthcare facilities also have high ventilation loads, but they are very sensitive to IEQ and are recommended for future demonstrations.
Required site information and site selection criteria were developed to assist in selecting demonstration sites and are listed in Table 2 through Table 5.
Table 2. Site Information
Building Name
Building Primary Activity
Location (city, state)
Building area (ft2)
Weekly operation hours
HVAC system type
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Table 3. High-Level Criteria
Owner is ready to move, interested in making the demonstration a success
Building staff will be accessible to the demonstration team
Access to return air ducts and space to install the air cleaning system
Outside air dampers are operable and can be controlled by the air cleaning system
Total air flow rate > 10,000 cfm
Outside air flow rates > 20% of total air flow rates
Greater than 50 hours per week with ventilation operation
Minimal or no use of manually operable windows
Other ventilation load reduction strategies implemented (DCV, ERV, etc.)
Building automation system allows link to the air cleaning system control platform or control of the OA dampers directly
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Table 4. Systems-Related Criteria
Chilled water metering available
Whole building electrical meter
Electrical submetering
Up-to-date mechanical drawings available
No large HVAC maintenance or replacement plans in the next year
All mechanical systems operational
Space/AHU relationship known
Available TAB report (vintage)
Available OA/Exhaust measurements
Building ventilation challenges (known IAQ issues, etc.)
Available occupancy and/or people count
Available trend logs from BAS
Table 5. Utilities-Related Criteria
Site has high utility rate
Site has demand charges or other incentives for peak load reduction
Site potentially has access to rebates for installation
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5 Demonstration Design5.1 Monitoring PeriodThis technology has the potential to impact HVAC operation year round, but primarily in the heating and cooling seasons when the conditioning of the extreme outdoor air temperatures and humidity levels are the most energy intensive. Continuous monitoring systems should ideally continue for 1 year, but at least 9 months for locations with significant heating and cooling loads and at least 6 months for locations with very few or no heating requirements. Short-term monitoring of IAQ and airflow rates should be conducted during each season to determine the impacts on elimination of specified contaminants of concern and to verify airflow rates. It may be of interest to follow up with each site after 1 year of operation to verify proper performance and interview the maintenance staff about relevant maintenance practices and unusual system behavior.
5.2 Baseline Energy Performance DeterminationThe ventilation baseline for most sites should be the as designed operation of the building. However, each site should be evaluated to ensure that the as designed OA ventilation rate satisfies the Standard 62.1 prescriptive VRP requirements. The OA ventilation rates may need to be adjusted if they are lower than the Standard 62.1 VRP rates. Proper operation of the OA dampers will be verified for each air system.
Performance analysis of the air cleaning system will best be determined by operating the system in alternating on and off periods during each season with the full monitoring system in place and short-term air quality measurements. The timing and frequency of the on-off periods will be determined for each site with technology vendor and the building operations staff. The off period will have to be long enough (perhaps a week or longer) to allow the building and building systems to fully achieve a new dynamic equilibrium with the ambient and operational conditions. Baseline O&M practices and costs will be gathered from interviews with the maintenance staff and review of maintenance records.
5.3 Baseline IAQ DeterminationThe IAQP in Standard 62.1 is a performance approach in IAQ and allows the OA ventilation rate to be reduced below the VRP provided that the IAQ is maintained within acceptable limits. Following the IAQP may actually lead to higher OA ventilation rates if it is determined that the IAQ is not within the acceptable levels with the VRP. Standard 62.1 does not define acceptable IAQ, but Appendix B is provided as an informative appendix that provides a summary of contaminant exposure limits and guidelines issued by several recognized authorities.
The first step of the baseline IAQ measurements is to determine the contaminants of concern (COC) in the building and measure their concentrations and the allowable COC concentration limits. Determining appropriate exposure maximum concentration limits involves working with the building owner to understand the potential contamination sources. Factors that go into the selection of appropriate maximum concentration limits include the types of occupants, how long are occupants in the space exposed to the contaminant (hrs/day, days/year, or continuous), and the potential sensitivity to contaminants (Williams and Deru 2015).
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5.4 Instrumentation and MonitoringThe instrumentation and monitoring plan is developed to determine the performance metrics in Table 1. The data requirements from Table 1 necessitate a combination of continuous measurements and short-term periodic measurements. A list of monitoring points and instrumentation for continuous measurements is presented in Table 6, and the short-term measurements in Table 7 will be taken once or periodically during both the baseline operation and the air cleaning system operation. The instrumentation and monitoring plans will support direct measurement of performance along with development and calibration of whole-building energy models.
Table 6. Continuous Performance Monitoring and Instrumentation
Monitoring Point Type of Measurement Units Instrumentation
Chiller or DX energy
Electrical or chilled water kWh or Btu
Watt-hour meters with current transformers, water flow meters and CHW supply and return temperatures
Air handling unit fan energy Electrical kWh Watt-hour meters with current
transformers
Building heating energy
Electrical, hot water, or gas kWh or Btu TBD
Whole building energy
Electrical, gas, and other fuels kWh or Btu TBD
Fan energy Electrical kWh Watt-hour meters with current transformers
Regeneration energy Electrical kWh Watt-hour meters with current
transformers
Space and return air CO2
CO2 concentration ppm CO2 sensors
Outdoor air CO2CO2 concentration ppm CO2 sensor
Space TVOC TVOC concentration ppb TVOC sensors
Space temperature Temperature °C T&RH sensors
Space RH RH %RH T&RH sensors
Ambient temperature Temperature °C T&RH sensor
Ambient RH RH %RH T&RH sensor
Global horizontal solar radiation Irradiance W/m2 Pyranometer
Wind speed Wind speed m/s2 Anemometer
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Table 7. Short-Term Performance Monitoring and Instrumentation
Monitoring Point Type of Measurement Units Instrumentation
Outside airflow rates Airflow rate m3/s TBD based on each site
Specific VOC species determined as potential COCs
Concentration TBD TBD based on contaminant
Formaldehyde concentration Concentration PPB TBD
Indoor air quality Occupant satisfaction of acceptable IAQ % Survey or untrained
panel
Operation and maintenance (O&M) costs
Interviews and work orders
$, number and types of work
ordersInterview O&M staff
A site-specific instrumentation and monitoring plan will be developed for each installation accounting for the technology installation, existing systems, and existing instrumentation. The final demonstration M&V plan should be reviewed with DOE, the technology vendor, and the building staff.
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6 Performance Analysis and AssessmentIn the final assessment, report on the following performance areas for each demonstration site with detailed monitoring:
IAQ performance, including CO2 and the COCs determined for each site
Thermal comfort conditions to ensure normal conditions are maintained and to include changes in the thermal conditions in the energy analysis if necessary
Ventilation rate changes
Daily, monthly, and annual energy and energy cost performance
O&M costs and requirements including training requirements and durability of equipment.
Occupant satisfaction survey results and any concerns, where applicable.
Report on these performance areas with the objectives in Table 1 via the following approaches:
Determine if the IAQ/IEQ performance with the air cleaning system operation meets the requirements of Standards 62.1 55. Compare peak and average contaminant concentrations with IAQ exposure limits established by the California Office of Environmental Health Hazard Assessment (OEHHA 2012), the World Health Organization (WHO 2010) or the National Institute for Occupational Safety and Health (NIOSH 2010).
When comparing energy consumption with and without the air cleaning technology, normalize results to control for weather differences between the baseline and technology test periods. Develop regression models to normalize energy consumption based on: (1) outdoor air temperatures or degree days; and (2) humidity. Other normalization factors will be considered if a strong correlation with energy performance is suspected and if the data necessary for normalization are readily available.
Determine the operational economic performance from annual estimated energy costs, maintenance costs, and projected cartridge replacement costs for each demonstration site. Complete a simple payback and return on investment calculation based on estimated air cleaning technology costs for a non-demonstration installation and the estimated operational costs.
Determine O&M requirements by interviewing the maintenance staff and reviewing maintenance records. Determine occupant satisfaction with occupant satisfaction surveys where applicable.
The results from the demonstration may be used to investigate applications and potential impacts beyond these demonstration buildings. Whole-building energy modeling using EnergyPlus (DOE 2014) with the DOE reference building models (Deru et al. 2011) will be applied to estimate the energy savings potential for a broader range of building types, operating schedules, and locations. The process of adding the air cleaning technology to the reference building models will consist of applying a modified outside air schedule, adjusted infiltration schedule when the air cleaning technology is on, a fan and pressure drop in the return airstream to represent the air
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cleaning technology, and a schedule for the regeneration fan and heat load. No other changes to the reference building models will be required.
The whole-building energy models can also be used to compare performance of this technology to alternative approaches to reducing ventilation air requirements such as dedicated outdoor air systems, demand controlled ventilation, and economizer operation.
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References ASHRAE (2013a). Ventilation for Acceptable Indoor Air Quality. ANSI/ASHRAE Standard 62.1. Atlanta, GA: American Society of Heating, Refrigerating and Air-Conditioning Engineers.
ASHRAE (2013b). Thermal Environmental Conditions for Human Occupancy. ANSI/ASHRAE Standard 55. Atlanta, GA: American Society of Heating, Refrigerating and Air-Conditioning Engineers.
Deru, M.; Field, K.; Studer, D.; Benne, K.; Griffith, B.; Torcellini, P.; Liu, B.; Halverson, M.; Winiarski, D.;Rosenberg, M.; Yazdanian, M.; Huang, J.; Crawley, D. (2011). U.S. Department of Energy Commercial Reference Building Models of the National Building Stock. NREL/TP-5500-46861.Golden CO: National Renewable Energy Laboratory.
DOE (2014). EnergyPlus Energy Simulation Software. Washington, D.C.: U.S. Department of Energy.
NIOSH (2010). NIOSH Pocket Guide to Chemical Hazards: Formaldehyde from http://www.cdc.gov/niosh/npg/npgd0293.html.
OEHHA (2012). Air Toxicology and Epidemiology from http://www.epa.gov/iaq/base.
Williams, S. and Deru, M. (2015). Retailer Ventilation Best Practice Guide. NREL Technical Report to be published.Golden CO: National Renewable Energy Laboratory.
WHO (2010). WHO guidelines for indoor air quality: selected pollutants. Denmark: World Health Organization Europe.
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