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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