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Accuracy of flow hoods in residential applications

To assess whether houses can meet performance expectations, the new practice of residential commissioning will likely use flow hoods to measure supply and return grille airflows in HVAC systems. Depending on hood accuracy, these measurements can be used to determine if individual rooms receive adequate airflow for heating and cooling, to determine flow imbalances between different building spaces, to estimate total air handler flow and supply/return imbalances, and to assess duct air leakage. This paper discusses these flow hood applications and the accuracy requirements in each case.

Advanced Duct Sealant Testing

Duct leakage is a major source of energy loss in residential buildings. Most duct leakage occurs at the connections to registers, plenums, or branches in the duct system. At each of these connections, a method of sealing the duct system is required. Typical sealing methods include tapes or mastics applied around the joints in the system. Field examinations of duct systems have shown that taped seals tend to fail over extended periods of time. The Lawrence Berkeley National Laboratory (LBNL) has been testing sealant durability for several years.

Air Tightness of New U.S. Houses: A Preliminary Report

Most dwellings in the United States are ventilated primarily through leaks in the building shell (i.e., infiltration) rather than by whole-house mechanical ventilation systems. Consequently, quantification of envelope air-tightness is critical to determining how much energy is being lost through infiltration and how much infiltration is contributing toward ventilation requirements. Envelope air tightness and air leakage can be determined from fan pressurization measurements with a blower door. Tens of thousands of unique fan pressurization measurements have been made of U.S.

An Overview of the U.S. Building Sector

From the skyscrapers of Manhattan to the Victorian houses of San Francisco and the shopping malls of Anytown, USA, buildings in the U.S. are remarkable for their variety. Variety in the type of building (commercial warehouse, manufacturing facility, institutional and office buildings, apartment buildings, condos, single-family dwellings, mobile homes and the like) translates to variety in occupancy and use, which in turn, means differences in energy requirements and indoor air quality concerns.

Analysis of U.S. Residential Air Leakage Database

The air leakage of a building envelope can be determined from fan pressurization measurements with a blower door. More than 70,000 air leakage measurements have been compiled into a database. In addition to air leakage, the database includes other important characteristics of the dwellings tested, such as floor area, year built, and location. There are also data for some houses on the presence of heating ducts, and floor/basement construction type. The purpose of this work is to identify house characteristics that can be used to predict air leakage.

ASHRAE's new residential ventilation standard

The major concern for HVAC's professionals is the engineering of indoor environments, but health and safety must be a primary concern too. In so far as people spend nearly 90 % of their time indoors - mostly at home -, residential ventilation ought to have a large emphasis in ASHRAE. In this article, today's sources are examined (combustion, microbiologicals, radon and soil gas, particles, VOCs), then ASHRAE's residential ventilation standard requirements are listed.

ASHRAE's Residential Ventilation Standard: Exigesis of Proposed Standard 62.2

In January 1999 ASHRAE's Standard Project Committee on "Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings", SPC 62.2P, approved ASHRAE's first complete standard on residential ventilation for public review and it was subsequently approved for release by ASHRAE. The standard is an attempt by the Society to address concerns over indoor air quality in dwellings and to set minimum standards that would allow for energy efficiency measures to be evaluated. The standard has requirements for whole-house ventilation, local exhaust ventilation, and source control.

Assessing the longevity of residential duct sealants

Duct leakage has been identified as a major source of energy loss in residential buildings. Most duct leakage occurs at the connections to registers, plenums or branches in the duct system. At each of these connections a method of sealing the duct system is required. Typical sealing methods include tapes or mastics applied around the joints in the system. Field examinations (both physical measurements and visual observations) of duct systems have shown that these seals tend to fail over extended periods of time.

Best practices guide for residential HVAC retrofits

This best practices guide for residential HVAC system retrofits is aimed at contractors who want guidance on delivering energy efficient, cost effective and innovative products. It has been developed around the idea of having packages of changes to the building HVAC system and building envelope that are climate and house construction dependent. These packages include materials, procedures and equipment and are designed to remove some of the guesswork from a builder, contractor, installer or homeowner decisions about how best to carry out HVAC changes.

Building Airtightness: Research and Practice

This report summarizes the state of the art on building air tightness by reviewing the current and recent literature on both research and practice. The focus of this report is on techniques to measure the tightness of the building envelope and on what has been learned by doing so. This report reviews over 100 of the most important publications relating to the topic. The report covered the fundamentals of air leakage including the hydrodynamics of leaks, which has led to all of the measurement techniques currently in use.

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