In 1995 Tacoma Power initiated a test of residential duct sealing to determine the feasibility of a full-scale program to improve the duct system in customer homes with central system electric heat.
The increasing power of personal computers has e:ncouraged a proliferation of building energy simulation software packages. The prospective user has no way to quantitatively judge the appropriateness of a given software package for a given design problem. To address this issue, the Building Energy Simulation Test (BESTEST) procedure was developed for systematically testing whole building energy simulation programs and diagnosing sources of predictive disagreement. The BES TEST procedure takes a "comparative testing" approach where a program is compared to itself or to other programs.
Forced air distribution systems in residential buildings are often located outside conditioned space, for example in attics, crawlspaces, garages and basements. Leaks from the ducts to these unconditioned spaces or outside can change flows through the registers and change the ventilation rates of the conditioned spaces. In this study, duct leakage flows were measured in several low-rise apartment buildings. The leakage flow measurements and other data about the apartments were used to develop a prototype apartment building.
In recent years, residential energy conservation research has focused attention on heating system distribution efficiency. Several field studies in the Pacific Northwest have found forced-air heating systems which have a majority of ducts located in unheated buffer spaces can lose as much as 3 0% of the equipment's heating output to duct air leakage and conduction loss. The magnitude of loss can be equivalent to the combined improvements in building shell insulation levels due to updated energy codes.
The primary purpose of a laboratory exhaust system is to remove and convey fumes from the fume hoods and laboratory spaces to an area for safe discharge. This requires discharge conditions that allow good dispersion and prevent re-entrainment. Since laboratories are usually designed for once through air ( 100% makeup air with no recirculation), a secondary purpose is energy recovery from the exhaust stream. Laboratory exhaust systems have typically one of two arrangements.
This paper describes the wind tunnel study conducted on behalf of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) to evaluate and quantify the effect of architectural screens on rooftop concentration levels due to effluent from short stacks. An equivalent stack height (ESH) concept is introduced, which is used to develop a stack height reduction (SHR) factor that may be used in conjunction with existing stack design procedures found in the 1997 ASHRAE Handbook-Fundamentals to account for the presence of architectural screens.
Laboratory exhaust stacks should be designed with sufficient height and exit momentum to avoid re-entry of exhaust and possible air quality problems, and the design should be evaluated before construction. One evaluation method is presented in this paper that combines dilution prediction equations from the 1997 ASHRAE Handbook-Fundamentals (1997} and a dilution criteria of Halitsky (1988). This method is less conservative than a geometric method in the ASHRAE Handbook and is less costly than wind-tunnel modeling.
While there is no convincing technical basis for current code requirements for crawl space ventilation, most codes still require operable vents and the practice is well established among builders and architects . While the evidence against venting is compelling to many if not most in the research community builders and code officials apparently want to see hard evidence. In this research project I measured weekly energy consumption for space heating for a 1150 square foot home in a climate with 5900 heating degree days.
Ventilation systems for residential buildings can be generally categorized as supply, exhaust, or balanced systems. Subcategories include: integration into central air distribution ducts, or single- or multipoint air distribution; This effort focused on establishing a design methodology for central-fan-integrated supply ventilation systems using an outside air duct to the return side of a central air distribution fan, with a specialized fan recycling control.
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