«ERNEST ORLANDO LAWRENCE BERKELEY NATIONAL LABORATORY Integrated Technology Air Cleaners (ITAC): Design and Evaluation William J. Fisk, Sebastian ...»
ERNEST ORLANDO LAWRENCE
BERKELEY NATIONAL LABORATORY
Integrated Technology Air Cleaners
(ITAC): Design and Evaluation
William J. Fisk, Sebastian Cohn, Hugo Destaillats,
Victor Henzel, Meera Sidheswaran, Douglas P.
Environmental Energy Technologies Division
Funding was provided by the California Energy Commission, Public Interest Energy
Research Program, Energy Related Environmental Research Program, through contract 500-10-052, via Contract DE-AC02-05CH11231 between the University of California and the U.S. Department of Energy.
DISCLAIMER This document was prepared as an account of work sponsored by the United States Government.
While this document is believed to contain correct information, neither the United States Government nor any agency thereof, nor The Regents of the University of California, nor any of their employees, makes any warranty, express or implied, or assumes any legal responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by its trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof, or The Regents of the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof, or The Regents of the University of California.
Ernest Orlando Lawrence Berkeley National Laboratory is an equal opportunity employer Acknowledgements Funding was provided by the California Energy Commission, Public Interest Energy Research Program, Energy Related Environmental Research Program, through contract 500-10-052, via Contract DE-AC02-05CH11231 between the University of California and the U.S. Department of Energy. The authors thank Marla Mueller for Program Management; Marion Russell for analyses of VOC samples, Rengie Chan for analysis of particle data, the home owners for making their homes available.
i PREFACE The California Energy Commission Energy Research and Development Division supports public interest energy research and development that will help improve the quality of life in California by bringing environmentally safe, affordable, and reliable energy services and products to the marketplace.
The Energy Research and Development Division conducts public interest research, development, and demonstration (RD&D) projects to benefit California.
The Energy Research and Development Division strives to conduct the most promising public interest energy research by partnering with RD&D entities, including individuals, businesses, utilities, and public or private research institutions.
Energy Research and Development Division funding efforts are focused on the following
RD&D program areas:
Buildings End-Use Energy Efficiency •
Environmentally Preferred Advanced Generation • Industrial/Agricultural/Water End-Use Energy Efficiency • Renewable Energy Technologies •
Integrated Technology Air Cleaners (ITAC): Design And Evaluation is the final report for task 2.1 of the Lawrence Berkeley National Laboratory Energy Efficiency Research Projects project (contract number 500-10-052) conducted by Lawrence Berkeley National Laboratory. The information from this project contributes to Energy Research and Development Division’s Buildings End-Use Energy Efficiency Program.
For more information about the Energy Research and Development Division, please visit the Energy Commission’s website at www.energy.ca.gov/research/ or contact the Energy Commission at 916-327-1551.
The primary objective of this project was to design, build, and test an air cleaner for residential use with the potential to substantially improve indoor air quality, or maintain indoor air quality unchanged, when outdoor air ventilation rates are reduced to save energy. Two air cleaners were designed and fabricated. The design targets for airflow rate, fan power, and projected cost were met. In short term laboratory studies, both units performed as expected; however, during field studies in homes, the formaldehyde removal performance of the air cleaners was much lower than expected. In subsequent laboratory studies, incomplete decomposition of some indoor air volatile organic compounds, with formaldehyde as a product of partial decomposition of volatile organic compounds, was confirmed as the explanation for the poor formaldehyde removal performance in the field studies. The amount of formaldehyde produced per unit of decomposition of other volatile organic compounds was substantially diminished by increasing the amount of catalyst on the filter and also by decreasing the air velocity. Together, these two measures reduced formaldehyde production, per unit destruction of other volatile organic compounds, by a factor of four, while increasing the removal efficiency of volatile organic compounds by a factor of 1.4. A company with a southern California office is conducting studies in conjunction with Lawrence Berkeley National Laboratory, with the goal of incorporating the ITAC catalytic air cleaning technology in their future commercial products.
Keywords: air cleaning, catalyst, energy efficiency, filtration, homes, ventilation
Please use the following citation for this report:
Fisk, William J.; Cohn, Sebastian; Destaillats, Hugo; Henzel, Victor; Sidheswaran, Meera;
Sullivan, Douglas P. Lawrence Berkeley National Laboratory 2013. Integrated Technology Air
Cleaners (ITAC): Design And Evaluation. California Energy Commission. Publication number:
TABLE OF CONTENTSAcknowledgements
TABLE OF CONTENTS
LIST OF FIGURES
LIST OF TABLES
CHAPTER 1: Project Objectives and Background
CHAPTER 2: Methods
Air Cleaner Design
2.1 Air Cleaning Technologies
2.1.1 Characterization of Prototype Air Cleaners in the Laboratory
2.2 Tests of Prototype Air Cleaners in Houses
2.3 Evaluation of strategies for increasing contaminant decomposition
2.4 CHAPTER 3: Results
Primary Air Cleaner Designs
3.1 ITAC secondary design
3.2 Tests of ITAC Prototypes in Laboratory
3.3 Tests of Prototype air cleaners deployed in houses
3.4 Evaluation of strategies for increasing contaminant decomposition
3.5 Outreach to facilitate product commercialization
3.6 CHAPTER 4: Discussion
CHAPTER 5: Conclusions
APPENDIX A: Alternate ITAC Design
LIST OF FIGURES
Figure 1: Long term removal of formaldehyde, acetaldehyde, acetone and other VOCs (O-VOC) with the manganese oxide catalyst applied to a particle filter (Sidheswaran, Destaillats et al.
2011, Sidheswaran, Destaillats et al. 2011a).
Figure 2: Example of VOC removal efficiencies of the ACF system (Sidheswaran, Destaillats et al.2012).
Figure 3: Filter element 2b, a pad filter containing activated carbon.
Figure 4: Filter element 4, a low efficiency pleated particle filter after treatment with manganese oxide catalyst.
Figure 5: Photographs of the modified air cleaner. The sheet metal fitting at the top is a temporary feature installed to facilitate sampling from the outlet airstream
Figure 6: Formaldehyde removal efficiency of ITAC1 in laboratory studies.
Figure 7: Formaldehyde removal efficiency of ITAC2 in laboratory studies.
Figure 8: VOC removal efficiencies of ITAC1 in laboratory studies.
Figure 9: VOC removal efficiencies of ITAC2 in laboratory studies.
Figure 10: VOC data from field studies in House 1 with and without operation of ITAC1............ 19 Figure 11: Formaldehyde data from field studies in House 1 with and without operation of two ITAC1 air cleaners.
Figure 12: VOC concentrations from field studies in House 2 with and without operation of ITAC2.
Figure 13: Formaldehyde concentrations from the field studies in House 2 with and without operation of ITAC2.
Figure 14: Indoor to outdoor ratios of particle count concentrations in House 1
Figure 15: Indoor to outdoor ratios of particle mass concentrations, for particles smaller than 2.5 µm, in House 2
LIST OF TABLES
Table 1: Filter elements in ITAC1 and ITAC2.
Table 2: Air flow rates, pressure drops, and fan power consumption.
Table 3: Results of tests with single VOCs in the inlet airstream, quantifying formaldehyde production rates
Table 4: Results of tests and model predictions with mixtures of VOCs in the inlet airstream, while varying catalyst loading, air velocity, and substituting activated carbon for a portion of the catalyst.
Introduction Reductions in outdoor air ventilation rates of homes could save substantial energy. However, without compensating measures, indoor air quality will often be degraded posing health risks for the occupants of the home. Energy efficient air cleaning systems that are effective in removing particles and volatile organic compounds could enable reductions in ventilation rates and energy savings while maintaining or improving indoor air quality Project Purpose The primary objective of this project was to design, build, and test an air cleaner for residential use with the potential to substantially improve indoor air quality, or maintain indoor air quality unchanged, when outdoor air ventilation rates are reduced to save energy.
Project Results Two air cleaners were designed and fabricated based on modifications of an existing commercially-available air cleaner. One unit, designated ITAC1, included a high efficiency particle filtration system and a catalyst-treated low-efficiency particle filter. The catalyst treated filter was included based on results of prior research showing that the catalyst was highly effective in destroying formaldehyde and moderately effective in destroying several other volatile organic compounds (VOCs). The second unit, designated ITAC2, added a filter containing granular activated carbon to the ITAC1 design. One additional air cleaner was designed, but not fabricated and tested because the design did not meet cost targets. This unit included a high efficiency particle filter system, a catalyst-treated low-efficiency particle filter, and an activated carbon fiber (ACF) cloth. The ACF cloth was effective in prior research in removing a broad spectrum of VOCs, but it needed to be regenerated each day using a small amount of heated air. The hardware for the regeneration process increased the projected cost of the air cleaner above the cost target.
The ITAC units provided or exceeded the target airflow of 71 L/s (150 cfm) at the medium and high fan speed settings with impressively low fan power (approximately 13 W at medium fan speed and 29 W at high fan speed). The goal was power consumption less than 60 W; thus, the ITAC units exceed this goal by a large margin. Both the ITAC1 and ITAC2 designs were based on easy modifications to an existing energy-efficient air cleaner with a known retail price. The incremental cost to modify the original products and mass produce air cleaners with the ITAC1 or ITAC2 design would be modest; thus, the anticipated final cost meets the cost target of $600 for a unit with a 71 L/s supply air flow rate.
In short term laboratory studies, both ITAC1 and ITAC 2 removed formaldehyde with approximately a 60% efficiency. ITAC1 removed several other VOCs with a 20% to 45% efficiency, while ITAC2 removed the same VOCs with a 40% to 90% efficiency.
The ITAC units were deployed in houses for approximately 40 day periods. They were operated most of the time, but turned off during some periods to obtain baseline data. Indoor and outdoor concentrations of VOCs, particles, and ozone were measured. A tracer gas system was employed to measure air exchange rates. During the field studies, the formaldehyde removal performance of the air cleaners was much lower than expected. Concentrations of particles decreased as expected. Indoor ozone concentrations were too low to enable an evaluation of the effect of air cleaner operation on ozone concentrations.