Darryl Dickerhoff

Sealing ducts in large commercial buildings with aerosolized sealant particles

LBNL-42414 Sealing Ducts in Large Commercial Buildings with Aerosolized Sealant Particles M. P. Modera, O. Brzozowski ** , F. R. Carrie * , D. J. Dickerhoff, W. W. Delp, W. J. Fisk, R. Levinson, D. Wang Abstract Electricity energy savings potential by eliminating air leakage from ducts in large commercial buildings is on the order of 10 kWh/m 2 per year (1 kWh/ft 2 ). We have tested, in two large commercial buildings, a new technology that simultaneously seals duct leaks and measures effective leakage area of ducts. The technology is based upon injecting a fog of aerosolized sealant particles into a pressurized duct system. In brief, this process involves blocking all of the intentional openings in a duct system (e.g., diffusers). Therefore, when the system is pressurized, the only place for the air carrying the aerosol particles to exit the system is through the leaks. The key to the technology is to keep the particles suspended within the airstream until they reach the leaks, and then to have them leave the airstream and deposit on the leak sites. The principal finding from this field study was that the aerosol technology is capable of sealing the leaks in a large commercial building duct system within a reasonable time frame. In the first building, 66% of the leakage area was sealed within 2.5 hours of injection, and in the second building 86% of the leakage area was sealed within 5 hours. We also found that the aerosol could be blown through the VAV boxes in the second building without impacting their calibrations or performance. Some remaining questions are (1) how to achieve sealing rates comparable to those experienced in smaller residential systems; and (2) what tightness level these ducts systems can be brought to by means of aerosol sealing. Ecole Nationale Superieure d’arts et Metiers (ENSAM), Paris, France On leave from Ecole Nationale des Travaux Publics de l’Etat, Laboratoire des Sciences de l’Habitat, DGCB – URA CNRS 1652, 2 rue Maurice Audin, 69518 Vaulx-en-Velin Cedex, France

Low pressure air-handling system leakage in large commercial buildings: Diagnosis, prevalence, and energy impacts

Air-handling system leakage reduces the amount of air delivered to conditioned spaces and in most cases wastes energy and money. Standards exist for where and how to measure system airtightness, but they tend to focus on new construction, and only on the high-pressure (1500–2500 Pa [6–10 in. w.c.])/ medium-pressure [500–1500 Pa (2–6 in. w.c.]) portions of the system. This article investigates air leakage in the low-pressure (≤500 Pa [≤2 in. w.c.]) portions of large commercial-building air-handling systems (i.e., downstream of variable-air-volume box inlet dampers). A simplified diagnostic protocol for measuring low-pressure leakage that can be used during normal system operation in an existing building is presented and utilized for this investigation. A validation of the protocol using a calibrated leak in a field installation is also presented, as are the results of applying this protocol in nine other buildings around the United States. The validation results indicate that normalized leakage can be measured to within 10 L/s at 25 Pa (20 cfm at 0.1 in w.c.), with and without the existence of significant flow through the minimum opening of the box inlet damper. The field test results indicate that low-pressure leakage varied considerably from system to system (standard deviation of 50% of the mean value), and that the average value was approximately 10% of the flow entering the low-pressure system sections. The variability of the measured results, combined with a simplified analysis of the impacts of this leakage, suggest that testing of low-pressure system leakage in commercial buildings should be economically justifiable.

Heating, Ventilating, and Air-Conditioning: Recent Advances in Diagnostics and Controls to Improve Air-Handling System Performance

The performance of air-handling systems in buildings needs to be improved. Many of the deficiencies result from myths and lore and a lack of understanding about the non-linear physical principles embedded in the associated technologies. By incorporating these principles, a few important efforts related to diagnostics and controls have already begun to solve some of the problems. This paper illustrates three novel solutions: one rapidly assesses duct leakage, the second configures ad hoc duct-static-pressure reset strategies, and the third identifies useful intermittent ventilation strategies. By highlighting these efforts, this paper seeks to stimulate new research and technology developments that could further improve air-handling systems.

A prototype data archive for the PIER 'thermal distribution systems in commercial buildings' project

A prototype archive for a selection of building energy data on thermal distribution systems in commercial buildings was developed and pilot tested. While the pilot demonstrated the successful development of the data archive prototype, several questions remain about the usefulness of such an archive. Specifically, questions on the audience, frequency of use, maintenance, and updating of the archive would need to be addressed before this prototype is taken to the next level.