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Residential Attics and Cathedral Ceilings |
introduction
As a result of this research program, we hope to gain a better
understanding of the construction, ventilation, thermal performance, and energy
flows of residential attics and cathedral ceilings. Improved attic testing
procedures and insulation strategies, along with a fundamental understanding of
the air distribution systems within attic spaces, will lead to better-insulated
and sealed ducts and more energy-efficient houses.
issues
The roof / ceiling of a house is one of the largest sources
of heating and cooling loads, representing about 20~30 percent of the heat
loss or gain through the building envelope. Many houses, especially
in the Sunbelt, have air distribution systems in attic spaces. Heat
gains and losses through the duct walls due to conduction and air leakage
to or from the attic air space can seriously degrade the overall energy efficiency
of the heating / cooling system. Even small improvements in the energy
efficiency of residential roofs / ceilings and attic air distribution systems,
if widely adopted, would result in large energy savings.
objectives
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Gain a fundamental understanding of the thermal performance of residential attics (including their interaction with attic ducts) and cathedral ceilings |
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Develop a handbook of practical technical data that describe ways to achieve cost-effective and energy-efficient attics and cathedral ceilings |
research
To allow laboratory studies of the thermal performance of residential
attics, an attic test module simulating typical residential construction was
built for use in the Large Scale Climate Simulator (LSCS).
This module has been used for measuring the in-service performance of
various types of attic and duct insulation under simulated winter and summer
weather conditions. Results from the attic duct studies have helped to
validate duct computer models which support the development of the ASHRAE 152P
duct efficiency standard.
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| Attic test module containing a suspended flexible duct system | Steel-framed attic system before insulation is installed between joists | Attention to instrumentation details for the steel-framed attic tests |
In addition to our work with attic ducts, we have been evaluating
and analyzing the thermal performance of steel-framed attic systems.
A test module to experimentally measure the thermal performance of a
steel-framed attic was designed, constructed, and used to measure the heat
loss through an attic with C-shaped steel framing. New ways to help
us better understand the physics of heat, moisture, and air flow in residential
attics with attic ducts were explored. To develop an attic energy efficiency
rating system, the thermal performance of traditional wood frame attic systems
serves as the baseline for comparison to innovative attic insulation strategies.
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