Chapter01.pdf

(593 KB) Pobierz
•
Passive solar designs are simple. This simplicity means
greater reliability, lower costs, and longer system
lifetimes.
Since passive systems have few if any) moving parts,
they perform effortlessly and quietly without mechanical
or electrical assistance. Simplicity lowers the cost of the
job. Without motorized dampers, automatic valves,
sophisticated control systems, or high-tech components,
much of the work can be done using standard building
materials and basic construction skills.
The most significant reason that passive makes sense
economically is that most passive designs are inherently
durable, lasting at least as long as the rest of the house with
little or no maintenance or repair. Conventional building
materials such as glass, concrete, and brick weather
well and are generally longlasting. For the life of the
house, a passive system should continually maintain, if not
improve, its value at least as well as the rest of the house. It
should require little more maintenance than a standard wall
or roof.
Because you can build passive designs in small sizes, the
initial effort need not involve a large financial commit-
ment. Instead, the first step can be relatively small with
correspondingly little risk.
For optimum performance, some passive systems
require daily or monthly adjustments of shades, shutters, or
vents. Although some people may at first regard this as an
imposition, it is really no more trouble than operating a
dishwasher or closing draperies in the evening. Before
long, passive-home residents will find these to be pleasant
routines that bring them closer to the flux of the
3
environment to which their homes are atuned. They are
usually rewarded with a rich and exciting living .
experience as a result of their efforts, while saving both
energy and money.
Radiant heat from large passive collecting surfaces is
usually more comfortable than the drafty heat of conventional
hot air or hot water heating. In well-designed systems,
temperature variations are small, generally within a range of
5° to 10º each day. But in less well designed houses,
temperatures can vary more widely. Some solar enthusiasts
feel such temperature fluctuations are natural, and not
uncomfortable, particularly at the higher end. In fact, many
passive home residents enjoy the warmer-than-usual
temperatures on a sunny winter day.
Passive solar systems save fossil fuels. The economy is
benefitted because the nation imports less oil. And since
passive energy systems do not require transmission lines,
pipe lines, or strip mines, they produce neither dangerous
radioactive wastes nor polluted air and water. Passive
systems have few negative consequences. They can use
renewable and recyclable materials, and they produce jobs.
If a house has low heating or cooling requirements, and if a
passive solar system is designed to provide only a small
fraction of the energy, the system can be small and have only
a slight effect on the overall appearance of a house. It need
not make the house unattractive. In fact, properly designed
passive houses can be more beautiful than conventional ones.
Picture it-large expanses
of south-facing glass overlooking your yard; a beautiful
sunspace filled with plants year 'round. You can save energy,
save money, and provide a better living environment, all at the
same time! Comparing a good passive house to a conventional
one is like comparing a modern, dependable lightweight bike
to the high-wheeled terrors of the 1890s.
I Thought You Said It Was Simple
It is. Every material and principle incorporated into passive
solar design is common and in everyday use. The melting of
an ice cube or the ability of a stone to stay warm long after
sunset-these are the kind of considerations on which all
passive design is based. The only trick is to learn the labels
so that it is easier to understand and discuss. Then you can
say "thermal mass" instead of having to say (each time you
discuss the phenomenon) "the ability of a stone to stay warm
long after sunset."
Conduction
The transfer of heat between objects by
direct contact.
Natural Convection
The movement of heat through the
movement of air or water.
Mean Radiant Temperature
The average temperature you experience
from the combination of all of the various
surface temperatures in a room-walls,
floors, ceilings, furniture and people.
Thermal Radiation
The transfer of heat between objects by
electromagnetic radiation.
Air Stratification
The tendency of heated air to rise and to
arrange itself in layers with the warmest
air at the top.
Evaporative Cooling
Natural cooling caused by water's ability to
absorb heat as it vaporizes.
.
,
Degree day
A unit used to measure the intensity of
winter. The more degree days there
are in total for the season, the cooler the
climate.
Windows
Windows let light (and heat) in and out).
Glazing
Layers of glass or plastic, used in
windows and other solar devices for
admitting light and trapping heat.

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika:

Zgłoś jeśli naruszono regulamin