EXAM 01 Flashcards
design intent
statement that outlines an expected high‐level outcome of the design process.
It should adequately express the defining characteristics of a proposed building solution
why are design intents important
they set the tone for design efforts, allow all members of the design team to understand what is truly critical to success, provide a general direction for early design efforts, and put key or unusual design concerns on the table
design criteria
benchmarks against which success or failure in meeting design intent is measured.
ensure that all involved parties seriously address the technical and philosophical issues underlying a project’s design intent.
east and west facade shading
vertical shading
horizontal overhang is somewhat effective when the sun is at high positions in the sky, but is not effective at low‐altitude angles
eggcrate shading devices (a combination of overhangs and fins)
north facade shading
receive direct solar radiation in the summer in the early morning and near sunset, when the altitude of the sun is very low. For shading on the north side at these times, vertical fins are most effective
south facade shading
horizontal overhang during the summer
shading mask
sunpath chart (horizontal projection) that shows the shadow cast by a particular shading device
what is the greenhouse effect
greenhouse gasses trap heat below the Earth’s atmosphere in more or less the same way that glass traps heat from solar radiation in a greenhouse (or in a passive solar heating system). This trapping of heat increases temperatures and leads to climate change
greenhouse gas includes CO2 and methane
carbon‐Neutral Design: designs that tries to reduce carbon emissions
code
government‐mandated and government‐enforced documents (typically via the building and occupancy permit process) that stipulate minimum acceptable building practices
may be a legislatively adopted standard
Examples: Chicago Building Code; International Building Code
standard
documents that present a set of minimum requirements for some aspect of building design; usually a consensus document developed by a professional organization under established procedures with opportunities for public review and input
Examples: ASHRAE Standard 90.1, Energy Standard for Buildings Except Low‐ Rise Residential Buildings; ASTM E413‐87, Classification for Rating Sound Insulation
design validation
simple design validation methods (such as broad approximations, lookup
tables, or nomographs) requiring few decisions and little input data are typically used early in the design process.
the later stages of design see the introduction of more complex methods (such as computer simulations or multi-step hand calculations) requiring substantial and detailed input
building validation
most common
post‐occupancy evaluation (POE)
Published POEs have typically focused upon some specific (and often non-technical) aspect of building performance, such as way‐finding or productivity
building commissioning
an independent commissioning authority verifies that design decisions and related building assemblies, equipment, and systems can meet the owner’s project requirements (accomplished through review of design documents, observation of component installation, and detailed testing of equipment and systems under conditions expected to be encountered with building use.)
building case study
attempts to present the lessons learned from one case in a manner that can benefit other cases (future designs)
green design
incorporate concern for the health and well‐being of building occupants/users and respect for the larger global environment.
should maximize beneficial impacts on its direct beneficiaries while minimizing negative impacts on the site, local, regional, national, and global environments.
an attempt to maximize the positive effects of design while minimizing the negative ones—with respect to energy, water, and material resources.
rating systems include LEED
sustainable design
involves meeting the needs of today’s generation without detracting from the ability of future generations to meet their needs.
green design is a necessary constituent of sustainable design.
“let nature do the work” principle
expresses a preference for natural/ passive processes over mechanical/active processes
designers can usually find ways to use natural processes on site where they occur, in place of dependence upon services from remote/nonrenewable sources
smaller buildings on larger sites are particularly good candidates for this strategy.
Example: Daylighting
efficiency of electricity delivery is lost
55% of energy is lost during delivery
two most important factors in climate type
latitude and humidity
austin is a mix of how many climates? what are they?
ATX is a mix of 3 climates:
hot/humid
hot/arid - courtyard
temperate - wood, straw bale, and cob (many hybrid homes:using more than one construction type)
austin is a _________ climate
sub-humid
Stable summers and unstable winters
High humidity during the day and low at night
Energy consumption is dependent on __________
the performance of the building envelope
U.S. has four zones ___________
cool, temperate, hot-humid, and hot-arid
embodied energy
indicator of how much energy must be invested to mine/harvest/produce, fabricate, and transport a unit of building material
recycling
Recycling is a form of reuse, but it is often more labor-intensive and potentially expensive (requires additional energy to transport and reconvert items into something new)
reuse
Reuse keeps building materials out of the waste stream, preserves embodied energy that was used to make the original item, creates less air and water pollution than making something new or recycling, and generates new business and employment opportunities
main difference between recycling and reuse
Reuse lengthens the life of an item, while recycling re-processes an item into a new raw material
malcolm wells
American architects regarded as the “father of modern earth-sheltered architecture
Advocated environmentally responsible design; buildings are the problem and solution to climate change
***His values ignited shift from energy-efficient to green to sustainable design
ecological footprint
concept that plots the gross resource demand of a geographic area as a footprint on the planet
If the footprint is larger than the geographic boundaries of the entity in question…
then the area is stepping on someone else’s environmental toes
how does population growth impact ecological footprint
continuing worldwide population growth, however, makes the footprint balance tenuous
Per capita energy and water use in the US appears to be stable and/or decreasing
analyzing the site
Recognize resources that exist on site and decide how to best integrate them
Schematic design plans should include sun and wind conditions, noise sources, and water runoff patterns
Important to identify microclimates on the site (the places that have special characteristics differing from the regional climate)
Microclimates on a site are not limited to those visible on site → vertical and horizontal site analyses are needed
Conditions of privacy and accessibility, view, heat, light, air motion, sound, and water all change with height above or below the surface
The position of the sun at any instant with respect to an observer on the ground is defined by its…
altitude and azimuth angle
altitude
angle between the horizon and the sun’s position above the horizon
important to consider for design and efficacy of sun shading devices and daylighting levels
altitude angle depends on…
both the observer’s position on the Earth and the seasonal changes/tilt of the Earth
altitude angle varies during the ______, beginning and ending at _________ and reaching daily max at ________
day; zero degrees; solar noon
altitude angle reaches yearly max on _______, yearly min on ________, and halfway points at _________
June 21; Dec 21; both vernal and autumnal equinoxes
azimuth is also known as…
solar bearing angle
azimuth angle
the angle along the horizon between the projected position of the sun and true (solar) north
important to consider when orienting a building on site, establishing building exposures, and analyzing shading angles
azimuth angle during its path from sunrise to sunset changes with _________ and __________
season and time of day
3 basic important solar pattern concepts
- The altitude of the sun is highest in summer, lowest in winter, and in between in spring and fall for all latitudes
- The daily maximum altitude of the sun increases as a location approaches the equator; but the seasonal altitude variations (the difference of the angle in winter versus summer) is the same for all latitudes - except extreme north/south latitudes where sun is above or below horizon for long time periods)
- The azimuth angle of the sun is dictated by the time of day and by the season; in N hemisphere the sun rises north of east in summer and south of east during the winter
mean radiant temperature
(Garrison’s Definiton: Temperature of every object in a room)
MEEB’s definition: the uniform temperature of an imaginary surrounding enclosure in which radiant transfer from the human body would equal the radiant heat transfer in the actual nonuniform enclosure
Radiant temperatures of surrounding surfaces influence human comfort
EX: MRT of ceilings in residential spaces can be high or become an issue because of attics above
3 reasons for the difference between solar and clock time
Location within a time zone - an observer located at any point other than directly on a standard time zone reference longitude must make a time correction for their distance from the reference longitude
Equation of time - the speed of the earth around the sun is nonuniform (the planet moves less rapidly in its revolution/orbital path when farther from the sun)
Daylight Saving Time - purpose is to make better use of daylight
solar vs. clock time
Actual length of a solar day varies because the earth’s rotation is more rapid when farther from sun (which is why days are shorter in the winter)
Since it’s impractical to use timepieces that need daily adjustment, we just use an average/mean solar day for timekeeping
most solar position tables (including sun path diagrams) are based upon ___________, not ___________
solar time, not clock time
solar north vs. magnetic north
Compass gives reading towards magnetic north, determined by Earth’s internal magnetic field - this is usually not the same as true north
It should be noted that the magnetic field is not uniform, stationary, or perfectly aligned with the Earth’s poles; thus, magnetic deviations can and have changed over time
To correct between magnetic north (compass) and true north (solar), a ____________ is applied to the ____________
magnetic deviation; compass reading
thermal comfort definition
condition of mind which expresses satisfaction with the thermal environment as assessed by subjective evaluation
3 categories of factors that affect comfort
Personal
Clothing and metabolism
Measurable environmental
Air temp, radiant temp, air motion, and humidity
Psychological
Color, texture, sound, light, movement, and aroma
Comfort studies have shown that ___________ is an important factor in cold conditions, whereas _____________ is most important in hot conditions
skin temperature; skin wettedness
_____ of total U.S. water consumption is by the building sector in buildings
12%
Groundwater depletion is ________
millions gallons/day
Water must be __________ because it is not a ___________
reused; renewable source
___________ remains the largest use of freshwater in the US
irrigation
drinking water from suppliers comes from mostly __________
surface water (potable water)
__________ are increasing overall water consumption, conservation provide some counterbalancing effect.
population increases
4 forms of water that most buildings come into contact with
Rainwater, groundwater, potable water and wastewater
Increase of population increased ____________ except for _______ (declined)
energy consumption; wood
suddenly (in geologic time) our planet is experiencing ________, ___________, and __________
population growth; nonrenewable resource depletion; measurable global climate change
on east and west facing windows, a __________ is somewhat effective when the sun is ___________, but is not effective at ___________
horizontal overhang; high positions in the sky; low‐altitude angles.
Interior shading devices are _________ than exterior devices but are _________
less effective; far more commonly used
reasons for this contradiction: not subject to weathering or dirt accumulation and generally are easier for users to adjust; designer who prefers a clean, apparently unchanging façade appearance will rely on interior devices—often at substantial energy cost
_______ windows often also need shading devices, contrary to the myth that __________________________
Northern; north façade never receives direct beam radiation
Tinted or fritted glazing reduces ____________ therefore reducing the ______________
the amount of sunlight that enters a space; amount of heat entering a building
More glazing can be placed on the __________ side of a building, less should be placed on the __________ side because _________
north; south; it receives more sun
east and west glazing need _________ shading
vertical
solar heat gain coefficient depends upon…
the type of glass and the number of panes, as well as tinting, reflective coatings, and shading by the window or skylight frame
passive cooling by cross ventilation or stack ventilation is a seasonal opportunity (and in many climates a seasonal need as well), limited to times when
the outdoor air temperature is lower than the indoor air temperature, and the outdoor humidity is at or below that desired indoors
When outdoor air temperatures are about the same as interior temperatures…
breezes might still be useful to increase interior air motion, thus extending the comfort zone
stack ventilation depends upon…
very low openings to admit outdoor air and very high openings to exhaust air
stack ventilation is driven by…
the principle that hot air rises
relative humidity
the amount of water vapor present in air expressed as a percentage of the amount needed for saturation at the same temperature
relative humidity is most readily controlled by _________ or ___________ means
mechanical or chemical
conduction
the movement of heat from one solid to another one that has different temperature when they are touching each other
convection
movement caused within a fluid by the tendency of hotter and therefore less dense material to rise and colder, denser material to sink under the influence of gravity which consequently results in transfer of heat
valley wind microclimate condition
climate is created in valleys between mountains that isn’t representative of the area because of the way the air/wind circulates
heat island effect
Most urban sites are under the influence of an urban subclimate that differs from the conditions of the surrounding countryside unaffected by urbanization. Probably the best‐known urban climate feature is the heat island. Designers should note that city climatological stations are often located at non urban sites, such as an outlying airport, masking the effects of a heat island
what is the most prominent envelope type in developed world
static
