OUTLINE
Introduction
Problem
What materials are better for insulation?
What designs are better for insulation?
Purpose
Background
Organizations Researching Problem
Materials
lustrous
dull
dark
light
Design
Windows
Enclosed
Hypothesis
Materials
Procedure
Summary
Materials that Work Best in Heat Efficiency
Designs that Work Best in Heat Efficiency
References
Introduction
Heat efficiency in any architectural design is always a topic that must be addressed.
Without this key element, structures would be totally inefficient to heat, not to mention
extremely expensive. In order to design a heat efficient building you must first
understand where heat is lost or where cold air enters the structure in question. My
research will first be to determine what materials are best for insulation and which
materials are not. Second, I will try to find where heat is most likely to escape in a
structure by researching efficient designs. This, in turn, will provide information to
where it is necessary to add more insulation to a particular structure.
Background
It has been proven time and time again that solar energy plays a crucial part in the
heating of any structure regardless of its design. The intensity of solar energy is
almost an exact constant only varying in energy about 0.2 % every 30 years. This
intensity on average is about 1.37 ( 106 ergs per second per cm2, or about 2 calories
per minute per cm2. This intensity can vary of course when the solar photons interact
with different conditions in the atmosphere. This energy from the sun can be converted
so that it is able to heat a structure in many different ways. During my experiment
though, I will only be testing the effects of a structure's heat related to passive
solar energy as illustrated in figure 1. Passive Solar energy is where the sun's heat is
able to heat a structure without the use of specialized equipment such as a photovoltaic
cell or other direct solar energy device.
Many organizations in such countries as Australia and England are conducting nationwide
heat energy efficiency ratings that can be used as references for engineers and
architects. These ratings could inform a designer as to what designs work better and
which do not. The program in Australia is titled the "Nationwide House Energy Rating
Scheme" (NatHERS) and became available to all designers who wished to use it early in
1995. A parallel program to the NatHERS is New Zealand's "Window Energy Rating Scheme"
(WERS) which allows homeowners to make better decisions about the selection and design of
window systems from an energy perspective. The WERS rating system will not be available
however until late 1996. Great Britain and many other nations have just recently begun
conducting their own Energy Efficiency Rating systems that will not become available to
the pubic until the early 21st century. So far though each of the research organizations
has been making their own discoveries that have already begun to effect architectural
designs of structures.
Often a structure's ability to collect heat is directly associated with the materials it
was built with. Depending on the material itself, it can either hinder or help the
structure's ability to collect heat. A lustrous material such as a mirror for example,
would reflect light but retain the heated photons. This effect would heat the structure
extremely well because of the lustrous surface's ability to attract light towards it and
collecting its heat. A dull material like natural wood, has proven not to attract much
light nor to collect a substantial amount of heat. Plain wood would not be a wise
decision to use if the material used in the structure was going to be how the structure
was heated. Most often structures are built with internal systems that produce heat.
The color of the material used to build a structure is also a key element. For the most
part the darker the color the more heat it attracts and the more heat it can store. A
structure that is entirely black in color will be far more easy to heat than one of any
other color. Exactly opposite to dark colors are light colors that do not attract much
heat at all and are not efficient at storing heat. The best combination is most often a
dark, lustrous material if heat is the desired effect. A completely wrong choice would
be materials that are dull and light in color unless cooling was the purpose.
The design of a structure can contain an infinite number of different elements each
either helping to make the structure efficient or hindering its ability. In my
experimentation I am only going to focus on two design elements. These two elements
pertain to if the structure has windows or if it is enclosed. The false-color image in
figure 2 shows heat eminating from a house in the form of infrared radiation. The black
regions radiate away the least amount of heat, while the white regions, which coincide
with the house's windows, radiate away the most heat (NASA,1991). Because of the fact
that solar energy can not be collected in any structure during the night, all of my
experimentation will be conducted around noon in order to create a constant. Figure 2
shows heat escaping mainly through the windows but does not show that during the day
windows are the most significant passive heat intakes for a structure. Windows are
however, a disadvantage if the structure is being placed in a highly shaded area such as
a forest. In this case heat would have to be contracted in some other way. A greenhouse
is probably one of the best examples of passive heating. Without the aid of any other
device, greenhouses are able to maintain a high temperature. As stated above, windows
are also responsible for most heat loss in a directly heated home. In fact windows
account for 41% of heat loss in a typical US home. Double-pane windows are one way to
decrease heat loss from a structure but do not solve the problem entirely. If the
structure is to be built in an area were lack of sunlight is not a problem then a
structure with many windows should not be a problem for heat loss. An enclosed structure
with no windows in theory should cut down on at least 41% of heat loss. This would also
cut down on a large amount of heat gained during the day by passive energy through
windows. That would then cause heating efficiency to decrease. Even though the
efficiency would decrease it would probably still be less than 41% making it the better
choice. Many designers do not choose to do this however because of the lack of view not
having any windows would cause. Also windows serve as decoration in many designs.
Research has shown that the best compromise is to have double-pane windows evenly placed
throughout the structure in order to prevent one particular area from becoming too cold
or too hot. Insulation in the walls, roof and floor is also a compromise. Too little
insulation allows an excessive amount of heat escape from a structure while too much
insulation allows almost no heat to enter. Most structures are directly heated from the
inside allowing more insulation to be applicable.
A combination of the right materials and correct design according to where the structure
is to be placed is crucial. If a structure built in a cold, cloudy, climate was to be
made purely of windows and white wood, the temperature inside the structure would be
close to the temperature outside. Structural design must include many various factors.
Only the three factors of luster, color and windows will be used in my experiment.
Hypothesis & Experiment
If different materials are used to build a scaled structure, then the structure with high
luster will have a higher temperature than the structure with low luster.
If different materials are used to build a scaled structure, then the structure with a
darker color will have a higher temperature then the structure with a light color.
If different materials are used to build a scaled structure, then the structure with an
enclosed design (no transparent areas) will have a higher temperature than the structure
with a transparent design.
MATERIALS:
1 sheet of standard sheet metal
1 sheet of brown box cardboard
2 sheets of black plexi-glass
1 sheet of white plexi-glass
1 sheet of clear plexi-glass
2 thermometers
1 stopwatch or alarm clock
1 jigsaw
1 roll of duct tape
PROCEDURE:
Using the jigsaw, cut the sheet metal into 5 5"(5" squares. Then do the same with the
cardboard.
Using the duct tape, secure the 5 squares or sheet metal together forming a cube with 1
side missing. Then do the same for the cardboard.
Place the 2 semi-cubes out side at about 11:00 a.m. with the missing side facing down.
Place the thermometers inside the semi-cubes and use the stopwatch or alarm clock to time
2 hours.
At about 1:00 p.m. check the thermometers and record the two temperatures in a data
table.
Using the 1st black sheet and the white sheet of plexi-glass, follow steps 1-4 the next
day.
Using the 2nd black sheet and the clear sheet of plexi-glass, follow steps 1-4 the 3rd
day.
SUMMARY
The experiment in this paper will probably support my hypothesis based on the research
collected. The NatHERS rating organization expressed that lustrous materials are much
more likely to collect and store heat better than dull materials. They also express that
darker colored materials will more often than not collect heat at a higher rate that that
of a color such as white. In addition to these theories SOLARCH (National Solar
Architecture Research Unit) has studied window advantages alongside WERS to support my
own theory that enclosed structures store more heat than transparent structures. Further
studies on my part could branch into the other areas of structural design and placement
providing a more in detailed plan for experimentation.
REFERENCES
"The Integration of Window Labeling in the Nationwide House Energy Rating Scheme
(NatHERS) for Australia".
John Ballinger, Deborah Cassell, Deo Prasad, Peter Lyons,.
SOLARCH- National Solar Architecture Research Unit
The University of South Wales
Sydney 2052 Australia
Internet
Behrman, Daniel. "Solar Energy: the awaking science",
Little, 1980
Butti, Ken and Perlin, John. A Golden Thread
Van Nostrard, 1980. "2500 Years of Solar Architecture and Technology"
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