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Passives Test 1

Terms in this set (100)

Often the massive structure of a building acts as a heat sink. Many massive buildings feel comfortably cool on hot summer days. During the night, these buildings give up their heat by convection to the cool night air and by radiation to the cold sky—thus recharging their heat-sink capability for the next day.
How Heat Sinks work in buildings?
The human being is a biological machine that burns food as a fuel and generates heat as a by-product.
The basic biological process by which we generate heat
F = 9/5C + 32
Celcius to Fahrenheit
Tropic of cancer
the most northern line at which the sun is directly over ahead at least one day of the year
Equator
the longitudinal line that's halfway between the North and South Poles, and divides the Earth into the Northern and Southern Hemispheres.
Tropic of Capricorn
the most southern line at which the sun is directly over ahead at least one day of the year
Artic circle
the most northern line at which there's at least one day that the sun doesn't rise or doesn't set
Antarctic Circle
the most southern line at which there's one day the sun doesn't rise or doesn't set
(F - 32) * 5/9 = C
Fahrenheit to Celsius formula
Solar Radiation
Emitted from the sun's surface +/-10,500 degrees Fahrenheit
Transmittance
Absorptance
Reflectance
Emittance
The 4 properties of Radiant Heat
Transmittance
the situation in which radiation passes through material
Absorption
the situation in which radiation is converted into sensible heat within the material
Reflectance
the situation in which radiation is reflected off the surface
Emittance
the situation in which radiation is given off by the surface, thereby reducing the sensible heat content of the object.
Systems Theory
The interdisciplinary study of systems. A system is a cohesive conglomeration of interrelated and interdependent parts that is either natural or man-made.
Passives Building Systems
As opposed to "Active" building systems, this does not rely on synthetically-produced energy to shape the environment they create. The design, placement, or materials optimize the use of heat or light directly from the sun.
Traps heat
What's the advantage of stone in architecture?
Spaceship Earth
R. Buckminster Fuller relates Earth to a spaceship flying through space. The spaceship has a finite amount of resources and cannot be resupplied.
The Ecosphere
A planetary closed ecological system. In this global ecosystem, the various forms of energy and matter that constitute a given planet interact on a continual basis
Geosphere, Biosphere, Atmosphere, Magnetosphere
The four components of the Ecosphere
The Whole Earth Catalog
Stewart Brand, in 1966, initiated a public campaign to have NASA release the then-rumored satellite photo of the sphere of Earth as seen from space, the first image of the "Whole Earth."
Vernacular Architecture
Native or peculiar to a particular country or locality. This architecture concerned with ordinary domestic and functional buildings rather than the essentially monumental
Anonymous, Adaptive, Iterative, Evolving, Responsive to Local Conditions, and Efficient in use of locally-available materials, energies, and technologies
Characteristics of vernacular architecture
Site (geology, hydrology, soils)
Topography (slope, accessibility)
Climate(temperature, humidity, solar angles)
Weather (rain, snow, wind, solar exposure)
What are some important factors in the ways buildings are designed in response to the environment around them?
Bioclimatic design approach
Architecture design methods could take advantage of the climate through the right application of design elements and building technology to energy saving as well as to ensure comfortable conditions into buildings
Arctic Circle, Tropic of Cancer, Equator, Tropic of Capricorn, and Antarctic Circle
Important longitudinal lines
Glare
caused by a significant ratio of luminance between the task and the source
Macroclimate
General climate of a region. Temperature extremes, Wind Velocity/Direction, Precipitation, Cloudiness, and Hours and days of sun
North Atlantic Current
clockwise ocean current that flows between Northern Europe and the Caribbean Sea
Thermohaline System
Density of Water caused by temperature and salinity
Microclimate
environmental conditions within a small area that differs significantly from the climate of the surrounding area
Tropical, Dry, Temperate, Continental, Polar
5 major climate zones in the Köppen-Geiger Climate Classification System
Windward side of a mountain (San Fran)
cool and moist due to expansion (low pressure)
Leeward side of a mountain (Reno)
dry and warm due to compression (high pressure)
1. Elevation above sea level
2. Form of land
3. Size, shape, and proximity of bodies of water
4. Soil types
5. Vegetation
6. Man-made structures
Main factors responsible for making the microclimate deviate from macroclimate.
Victor Olgyay
Wrote "Design with Climate"
Comfort Zone
It is the temperature range in which the body doesn't shiver or sweat, but has an idiomatic sense of a place where people feel comfortable, where they can avoid the worries of the world
Thermal Lag
process by which a body stores heat and releases it at a later time
Conductivity
The ability of an object to transfer heat or electricity to another object
Greenhouse Effect
This is vital for understanding both solar energy and climate change. This effect is due to the fact that the type of interaction that occurs between a material and radiant energy depends on the wavelength of that radiation.
Geothermal Energy
Energy from steam or hot water produced from hot or molten underground rocks
Latitude, Elevation, and Proximity to major bodies of water
Macroclimate is dependent upon what 3 things?
Wind Chill
Equal to the still-air temperature that would have the same cooling effect on a human being as does the combined effect of the actual temperature and wind speed.
Azimuth
A horizontal angle measured clockwise from north or south.
Altitude
Elevation above sea level
Solar Noon
Time of day when the Sun reaches its highest point in the sky for a given place on Earth.
Ecliptic
Plane that contains Earth's orbit around the Sun.
Solar Window
9am - 3pm Solar Time. Area of sky between sun paths at summer solstice and winter solstice for a particular location
Albedo
A number that indicates how much of the solar radiation is reflected from a surface. Reflectiveness of the surface measured from 0.0 to 1.0 (proportion of radiosity to irradiance)
Solar Envelope
Developed by Ralph Knowles. It has potential for not only ensuring high quality solar access, but also generating attractive architecture
Longitude
Distance east or west of the prime meridian, measured in degrees
Latitude
distance north or south of the Equator, measured in degrees
Solar Altitude
the angle of the sun above the horizon at any given latitude
Distance from Sun
92.96 million miles
The atmosphere acts like a greenhouse by allowing most of the solar radiation to enter but blocking the long-wave infrared radiation from leaving the planet
What's the effect of atmosphere on solar radiation?
Solar hot water heating
the conversion of sunlight into heat for water heating, requires access year-round
Solar space heating
requires access in only the winter (bottom half of the solar window)
Sensible heat
The random motion of molecules is a form of energy. Can be measured with a thermometer
Latent Heat
The amount of heat needed to bring about about a one degree change in temperature which results in a PHASE CHANGE in a volume of material is -much- higher than the amount needed to change the temperature one degree when no phase change is being caused
Phase change
A change of state is also known as
Radiant Heat
A form of electromagnetic radiation. All bodies facing an air space or a vacuum emit and absorb radiant energy continuously. Hot bodies lose heat because they emit more energy than they absorb
Evaporation
A large amount of heat is required to make sweat evaporate from the skin. That is why sweating is such an effective cooling mechanism.
Equilibrium Temperature
a consequence of both the absorptance and the emittance characteristics of a material.
1. Radiation
2. Conduction
3. Convection
4. Transportation
The 4 types of Heat Transfer
Heat Sink
A component that increases the heat flow away from a hot device
Heat Capacity
The amount of heat required to raise the temperature of a material by 1 degree.
Thermal Resistance
The property for a material to resist the flow of heat through it. Largely a function of the number and size of air spaces the material contains.
Thermal Conduction
The transfer of heat internal energy by microscopic collisions of particles and movement of electrons within a body
Thermal convection
The transfer of heat from one place to another by the movement of fluids. Usually the dominant form of heat transfer in liquids and gases.
Time Lag
the delay of heat flow
Radiation
Affected by the nature of the material with which it interacts and especially the surface of the material
U- Value
The amount of heat that can be lost from a building. The lower the value in this, the better heat efficiency there is. U = 1/RT
R- Values
measure the thermal resistance of a given material. R = ft^2 × °F/Btu/h (Btu/h = heat flow per hour)
Hypothermia
Excessive heat loss
Hyperthermia
Insufficient heat loss
Air Temperature
This factor will determine the rate at which heat is lost or gained to / from the air - mostly by convection. The comfort range for 80% of people extends from 68° in the winter to 78° in the summer.
Thermal Comfort
The range of indoor air temperature that most building occupants are comfortable at. We must understand not inly the heat dissipation mechanisms of the human body.
1. Air temperature
2. Relative Humidity
3. Air Movement
4. Mean Radiant temperature (MRT)
Four environmental conditions that allow the heat to be lost
Relative Humidity
The ratio of the partial pressure of water vapor in the mixture to the equilibrium vapor pressure of water over a flat surface of pure water at a given temperature (an indication of the evaporation rate)
Mean Radiant Temperature (MRT)
The weighted average of all of the temperatures of all of the surfaces visible from a given position. When it differs greatly from the air temperature, its effect must be considered
Heat
Energy that is transferred from one body to another as the result of a difference in temperature
Air Movement
Affects the heat lost rate by both convection and evaporation
Thermal Stratification
Occurs when two types of steam with different temperatures come into contact. Their temperature difference causes the colder and heavier water to settle at the bottom of the pipe while allowing the warmer and lighter water to float over the colder water.
Dry Bulb Temperatures
Read by a thermometer freely exposed to the air, but shielded from radiation and moisture. This is the true thermodynamic temperature and is what is usually thought of as the air temperature.
Wet Bulb Temperatures
Read by a thermometer covered in water-soaked cloth over which air is passed. At 100% relative humidity, the wet-bulb temperature is equal to the dry-bulb temperature and it is lower at lower humidity.
Absolute Humidity
Total mass of water vapor present in a given volume or mass of air. Does not consider temperature.
Dew Point Temperature
When an air sample is cooled sufficiently, its RH increases until is reaches 100 percent, which is also called the saturation
Saturation
Once a mass of air is cooled past the Dew Point Temperature it reaches what
Condensation
The change of state from a gas to a liquid
Precipitation
Any form of water that falls from clouds and reaches Earth's surface.
Enthalpy
The total heat content of air. (Sensible + Latent Heat)
Psychometric chart
The horizontal axis describes the temperature of the air, the vertical axis describes the actual amount of water vapor in the air, called humidity ratio or specific humidity, and the curved lines describe the relative humidity (RH).
Adibiatic Change
In evaporative cooling, the increase in Latent Heat equals the decrease in Sensible Heat. This is a change in which total heat content of the air remains constant.
Heat loss
Some heat is lost by exhaling warm, moist air from the lungs, but most of the body's heat flow is through the skin
The effect of Metabolic Rate
To maintain thermal equilibrium, we must lose heat at the same rate at which our metabolic processes produce it
Thermal Barriers
clothes, buildings, canopy bed, fire place, drapes, etc...
It has potential to cause great discomfort or comfort. In the summer, it is a great asset and in the winter a liability.
The effect of Air Movement on comfort
The insulating effect of mass
If the temperature difference across a massive material fluctuates in certain specific ways, then the massive material will act as if it had high thermal resistance
Sky vault
an imaginary dome place over the building site, where lines indicate the sun's path
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