From: Essential Information <ei@igc.apc.org>
Newsgroups: sci.energy
Date: 31 Dec 92 12:42 PST
Subject: Re: Energy Ideas - Thermal Env.
Nf-ID: #R:cdp:1466300127:cdp:1466300128:000:3129
Nf-From: cdp.UUCP!ei    Dec 31 12:42:00 1992




ENERGY IDEAS -- Building Envelope (Vol. 1, No. 4, October 1992)


Jonathan Kleinman, Editor (202) 387-8034, ei@ipc.agc.org
Eleanor Lewis, Director, Government Purchasing Project
Ralph Nader, Founder, Center for Study of Responsive Law


SEALING THE ENVELOPE

A building shell, also known as a building "envelope," plays a
crucial role in the energy efficiency of a structure.  Many
buildings constructed in the 1950s and 1960s lose a tremendous
amount of energy through their shells.  Properly insulating,
sealing and coating a building dramatically improves its energy
performance in all seasons.

Each component of the building shell has the potential to allow
heat to leak through it.  For example, windows, while they
contribute to occupant comfort, also contribute to energy loss. 
According to the Solar Energy Industry Association (SEIA), office
buildings account for about one-third of all energy used yearly
in the United States.   These same buildings lose approximately
25 percent of their energy by unwanted gain or loss of heat or
the infiltration of unwanted air through windows.  According to
the Alliance to Save Energy, almost two-thirds of our commercial
space has no more than single-paned windows.  As a result, every
year, an amount of energy equal to the annual oil flow through
the Alaskan pipeline leaks through windows, cooling buildings in
the winter and heating them in the summer.  Also, uninsulated
ceilings, walls and roofs allow the conduction of heat and the
infiltration of unwanted hot or cold air.

Many technologies, both standard and innovative, can improve the
ability of a building to minimize heat transfer.  Insulated
windows ~ either aerogel or multiple-paned ~  can prevent the
conduction of heat through glass.  Low-emissivity (low-E) windows
and window films allow windows to reflect heat rather than
transmit it, keeping rooms cool in the summer and warm in the
winter.  Fiberglass insulation in walls, ceilings and roofs will
limit temperature gain and loss.  Buildings can use natural
sunlight to illuminate and heat workspaces.  And radiant barriers
can prevent radiative heat (the heat traveling as infrared light
which can be felt far from an object), which insulation does not
stop, from entering or leaving a building.  

New technologies can significantly improve the thermal
performance of buildings.  For example, part of Rocky Mountain
Institute operates from a 4,000-square-foot house in Old
Snowmass, Colorado.  By using super-insulation, "tight"
construction and passive solar design, the building, which
includes a large library, a computer room, 20 work stations,
seven computers, two photocopiers, a fax machine, a plotter, two
laser printers and the home of Amory and Hunter Lovins, has a
total utility bill of five dollars per month.  According to Amory
Lovins, Executive Director of Rocky Mountain Institute, on a
January day without solar heating, the building will only lose
about 0.8 degrees fahrenheit in temperature.

This issue of Energy Ideas presents available and developing
technologies which improve the thermal performance of building
envelopes.