May 21, 2009

The NCEMBT released the Final Report NCEMBT-090213 entitled Laboratory Performance Of In-Line Duct Air Cleaners For Residential Buildings authored by Jingjing Pei, Wenhao Chen, Jianshun S. Zhang PhD, all of Syracuse University and Davor Novosel of the NCEMBT. T his work was conducted under the  NCEMBT Task 05-03:  Laboratory Performance Of In-Line Duct Air Cleaners For Residential Buildings.

The previous NCEMBT Task 8 documented the laboratory performance of “off the shelf” air cleaners, including six portable and two in-duct devices.  The research findings have been published in the NCEMBT Report-061101 (Chen 2006).  This project builds upon the results of Task 8.

Three additional in-duct air cleaners have been evaluated in this project, and results are reported for their initial combined removal effectiveness for particulates and volatile organic compounds (VOCs).  All the tests were performed in a stainless steel environmental chamber using a “pull-down” test procedure. Tests for three devices were conducted with simultaneous injection of particles ranging in diameter from 0.10 to 11μm and a mixture of eight representative VOCs. 

The test of an in-duct air cleaner employing ultraviolet-photo-catalytic oxidation technology (UV-PCO) which previously was tested in Task 8 was conducted with injection of only iso-butanol or iso-propanol with the purpose of evaluating potential by-product generation from the device.

Other important parameters, including power consumption, and pressure drop were also measured.  In addition, tests with sampling at multiple points inside the chamber and HVAC ducts system were conducted to correlate the two performance parameters for in-duct devices: single pass efficiency and the Clean Air Delivery Rate (CADR). The potential effectiveness and energy benefit of using such devices to clean recirculated air versus the use of heating, ventilating and air-conditioning (HVAC) systems to condition ventilation air are briefly discussed and compared. 

The major findings are:

• Sorption is an effective method to remove indoor VOC contaminants. The removal efficiency for most VOCs (except dichloromethane and formaldehyde) is 70~85% for product D1 (employing a pleated filter embedded with activated carbon), 15~20% for product D2 (employing a 50/50 blend of activated carbon and potassium permanganate(KMnO4) impregnated alumina) and 50~60% for product D3 (employing an 1 inch thick in-house-packed bed with a 50/50 blend of activated carbon and KMnO4 impregnated alumina).  The removal efficiency for a specific VOC is related to its physical and chemical properties.  For sorption technology, a heavier and lower volatile compound had, as expected, a higher absorbability on activated carbon than a lighter and more volatile compound.  The removal efficiency of dichloromethane for all the three products was relatively low compared with that for other compounds (except formaldehyde). Devices using KMnO4 impregnated alumina demonstrated a higher removal efficiency for formaldehyde (7.2% for D2 and 25.6% for D3) than plain activated carbon (as in D1).
   
• The generation of by-products is an important issue with regard to the application of UV-PCO devices. Short-chain alcohols (e.g., iso-butanol and iso-propanol tested in this study) are considered to be the most important precursors to formation of by-products.  The injection of iso-butanol and iso-propanol resulted in generating formaldehyde, acetaldehyde and two other compounds, which could not be identified. 
   
• The single pass efficiency of MERV 8 and MERV 13 rated particle filters as derived from the “pull-down” test method, which is similar to the CADR test method specified by the Association of Home Appliance Manufacturers (AHAM) Standard ANSI/AHAM AC-1-2002, was found to be lower than that derived using the method of test specified in ASHRAE Standard 52.2-1999.   This may be attributed to the differences in the test procedures themselves and the method of particle loading for testing.  The decay rate, and therefore the CADR, for larger particles (e.g. 5.233-11.548 μm) could not be calculated from the standard “pull-down” test procedure due to fast removal rate of particles, which resulted in an insufficient number of data points.
   
• The well-mixed-zone assumption for particles in the environmental chamber was found not to be valid due to depositions of particles.  This was especially true for large particles.  This lead to differences in the calculated single pass efficiencies derived from measuring the concentration of particles directly up- and down-stream of the filter, aka “direct method”, and the CADR method which is based on the decay of particle concentration in the chamber.
   
• A method has been developed to correlate the results from the CADR method with those from the direct method, accounting for the incomplete mixing and deposition in the chamber and the duct system.
  
   

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April 15, 2009

The NCEMBT released the Final Report NCEMBT-090417 entitled Development Of An Operation And Maintenance Rating System For Commercial Buildings authored by Rich Prill and Rick Kunkle of Washington State University Extension Energy Program and Davor Novosel of the NCEMBT. This work was conducted under the NCEMBT Task 06-09:  Development Of An Operation And Maintenance Rating System For Commercial Buildings.

The purpose of this market transformation pilot project was to create a rating system framework to score or rate the performance of commercial buildings.  The building performance factors addressed by this project are building energy usage; operation, maintenance, and functionality of the heating, ventilation and air conditioning (HVAC) systems; building occupant satisfaction; and building operation and management.  Basic and routine industry-accepted O&M practices are prerequisites to the rating system.

A detailed rating or scoring method was created for four building performance parameters:  1) HVAC Roof Top Unit O&M and Performance; 2) Building Energy Performance; 3) Building Occupant Satisfaction; 4) Walk-Through Assessment.

Six pilot project buildings in Washington State were recruited and used to obtain input from the building owner/manager, occupants, and O&M service providers and to field test the proposed rating system tools.  Each of the pilot building’s energy usage was documented and the operation and functionality of some HVAC systems were evaluated.  Occupant satisfaction surveys were conducted in conjunction with space temperature and ventilation assessments.    Limited technical monitoring was performed.

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February 6, 2009

The NCEMBT released the Final Report NCEMBT-090116.2 entitled Emerging Filter & UV Devices For Energy Efficient IAQ In Commercial Buildings - Volume 2: Germicidal Lamp Testing authored by William Bahnfleth, Ph.D., PE, Josephine Lau, Paul Kremer, Daniel Clark and James Freihaut, Ph.D. of the Indoor Environment Center, Department of Architectural Engineering, The Pennsylvania State University, University Park, PA  and Davor Novosel of the NCEMBT.

As part of a program to improve the capability to design and operate ultraviolet germicidal irradiation (UVGI) systems effectively, two facilities for UV lamp testing were developed by the Indoor Environment Center of the Pennsylvania State University Department of Architectural Engineering.  The facilities are intended to support research to understand key germicidal lamp performance characteristics under a range of application conditions over the lamp lifetime.  This work was conducted as part of the NCEMBT Task 05-02 Emerging Filter and UV Devices for Energy Efficient IAQ in Commercial and Institutional Buildings.

One facility is a temperature-controlled variable flow duct loop for testing the response of lamps to the air temperature and velocity to which they are exposed.  The dimensions of the duct and the range of flow rate it can produce are the same as specified for an ASHRAE Standard 52.2 filter test rig.  Lamp irradiance is measured with a precision radiometer and, concurrently, lamp surface cold spot temperature (which determines the relative lamp output) is measured by an infrared camera.  The other facility is a lamp depreciation and lifetime testing facility in which lamps can be operated at arbitrary on-off cycling rates and at different fractions of their design current.  The purpose of this facility is to determine depreciation curves and maximum life for lamps as a function of their operating history. 

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February 4, 2009

The NCEMBT released the Final Report NCEMBT-090116.1 entitled Emerging Filter & UV Devices For Energy Efficient IAQ In Commercial Buildings - Volume 1: Filter By-Pass Research authored by Paul Nigro, David Chojnowski and Douglas Kosar of University of Illinois at Chicago and Davor Novosel of the NCEMBT.

The research involved quantitatively determining the effects of filter bypass on efficiency experimentally using a ASHRAE 52.2 test loop.  The research was conducted in collaboration with Dr. Jeffrey Siegel from the Department of Civil, Architectural and Environmental Engineering at the University of Texas at Austin based on his prior experience with filter bypass.  This work was conducted as part of the NCEMBT Task 05-02 Emerging Filter and UV Devices for Energy Efficient IAQ in Commercial and Institutional Buildings.

Two filter bypass test matrices were developed.  The first, referred to as the constant pressure drop test matrix, involved holding the pressure drop across the filter constant with and without presence of bypass.  As the presence of a gap would decrease the pressure drop across the filter, the blower speed would be increased until the pressure drop without bypass was achieved.  The difference in airflow between the bypass and “no bypass” setups was considered the airflow through the bypass gap.  This airflow along with the “no bypass” efficiency results were used to generate an analytical bypass model.  

The second matrix was the constant fan speed matrix.  For this matrix, the blower speed was held constant to demonstrate what would happen in the “real world” when bypass is present in a HVAC system.  Both of the above matrices consisted of different types of filters in several bypass configurations with varying gap sizes on one side of the filter.  

To cover a range of filter efficiencies, a MERV 2, 7, 11 and 14 filter respectively was tested.  The bypass gap sizes of 0.25, 0.75, and 1.25 inch were chosen based on results from prior bypass research performed by Dr. Siegel.  The bypass configurations included straight bypass, U-shaped, and U-shaped “real.”  Straight bypass consisted of a gap between the edge of the filter and the duct wall.  U-shaped bypass involved a u-shaped channel installed on the bypass side of the duct which simulates a filter rack commonly found in field installations.  In this configuration the filter is centered with the channel.  The u-shaped “real” configuration included the same u-shaped channel installed in a different position.  In this case the filter edge was inline with the back edge of the u-shaped channel.  This configuration was done to similate the effect of the airflow pushing the filter up against the channel and creating an artificial seal between the filter and the channel. 

The results from all of the tests were plotted on removal efficiency versus particle size graphs.  Efficiency plots without bypass are also included in the graphs and were used as benchmarks to compare to efficiency plots with bypass. 

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December 16, 2008

The NCEMBT released the Final Report NCEMBT-081215.1 entitled Measurement And Verification Of High Performance Residential Buildings In Cold Climates, Volume 1 authored by Vijay Viswanathan and Christine Walker, Ph.D. of the University of Illinois at Chicago and Davor Novosel of the NCEMBT.

This report covers work performed under Task 14, the Measurement and Verification of High Performance Residential Buildings in Cold Climates which is a two part project for two cold climate locations: Northern Illinois and Central New York State.  The Task 14 research builds on the preceding NCEMBT Task 4: High Performance/Zero Energy Residential Buildings in Cold Climates.  Task 4 identified focus areas to improve the performance of single-family homes, working toward the Building America (BA) goal of 30 percent whole house energy reduction over the BA Benchmark home 2005 definition.  The concurrent parts of this project are being performed by the University of Illinois at Chicago (UIC) in Illinois and Syracuse University (SU) in New York.  

This report focuses on the Northern Illinois home.  A separate volume (NCEMBT-081215.2) reports on the findings of the Central New York home.

The objective of this project was to demonstrate that using currently available technologies homes can be constructed that exceed the BA Benchmark.  A high performance (HP) home designed and constructed by Claretian Associated and located in South Chicago was modeled using EnergyGauge® software as well as monitored from February 15, 2007 through September 8, 2007.  The home was predicted to exceed the BA Benchmark by 31 percent with a predicted consumption of 7798 kWh of electricity and 1125 therm of natural gas.  Based on the measured energy consumption over the monitoring period the annual consumption of electricity is predicted at 7064 kWh and 685 therm of natural gas.  Furthermore, the home features a photovoltaic array which is predicted to produce 1325 kWh of electricity annually based on the actual performance during the monitoring period.  Based on the above values the Claretian home exceeded the BA benchmark by 35 percent.

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December 12, 2008

The NCEMBT released the Final Report NCEMBT-081208 entitled Energy Performance and Environmental Characteristics of Educational Facilities – Extension and Enhancement of the Building Normative Database authored by Linda Stetzenbach, Ph.D. and her colleagues at the University of Nevada Las Vegas as well as James Craner, M.D. and his associates at Verdi Technology.

This study was tasked to provide data on the indoor environmental quality and energy consumption across ten schools in the United States and to correlate those data with responses of teachers to a computer-based questionnaire focused on their perception of their indoor work environment.  This study builds upon the protocols developed under NCEMBT Task 1. 

Ten schools were selected based on building design and construction characteristics as determined by a series of screening questions answered by the schools districts’ facilities department personnel.  This included the physical characteristics of the building, the age of structure, its geographical location, and type of mechanical air handling system. 

The computer-based occupant perception questionnaire was refined to obtain information from the teachers rather than office personnel regarding their perception of IEQ, lighting, and sound in their classroom and to obtain sufficient data to verify or refute the underlying hypotheses of the measurements.

In each school six classrooms (zones/locations) were selected from teachers willing to have the equipment in their classroom and were representative of the school’s configuration.  No temporary (portable) classrooms, lunchroom, or administrative areas were included as sampling locations/zones.  Measurement instrumentation was located in each of the six indoor locations/zones.  Additionally, an outdoor location was selected for some specific IEQ measurements.

The report provides detailed results on thermal comfort (i.e., temperature, relative humidity, and draft), carbon dioxide (CO2), surface, and airborne mold, and volatile organic compounds (VOCs) as well as lighting and acoustics.  Cumulative energy usage data derived form utility bills is also given.  The measured comfort parameters are compared with the results of the survey of the occupants' perceptions of their indoor environment. 

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