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Design Science 3 Midterm Terms

Terms in this set (48)

kW
- kilowatt (1000 watts)
kWh
"Electricity is measured in kilowatt‐hours (kWh) . One kWh of energy is equal to 1000 watt hours and will power a 100 watt light bulb for 10 hours (100 watts x 10 hours = 1,000 watt‐ hours = 1 kWh)."
BTU
- British Thermal Unit - the amount of energy needed to cool or heat one pound of water by one degree Fahrenheit
Power Usage (kWh) =
Power (kW) X Time (hrs)
Environment
- 1: the circumstances, objects, or conditions by which one is surrounded
- 2 a: the complex of physical, chemical, and biotic factors (as climate, soil, and living things) that act upon an organism or an ecological community and ultimately determine its form and survival b: the aggregate of social and cultural conditions that influence the life of an individual or community
Technology
- 1 a: the practical application of knowledge especially in a particular area : engineering 1 b: a capability given by the practical application of knowledge "a car's fuel-saving technology"
- 2: a manner of accomplishing a task especially using technical processes, methods, or knowledge "new technologies for information storage"
Vernacular
Of or being an indigenous building style using local materials and traditional methods of construction and ornament, especially as distinguished from academic or historical architectural styles.
Regionalism
The use of regional characteristics, as of locale,
custom, or speech, in literature or art.
angle of declination
the angle of the tilt of the Earth's axis with respect to an assumed horizontal plane, one within which the Earth tends to move as it circles around the sun.
Normal
an angle that is perpendicular to a plane
angle of incidence
is the angle that the solar ray makes with a line
normal to the surface under consideration.
azimuth angle
is the angle used to indicate the bearing of the sun
relative to the north-south axis (typically taken relative to south).
altitude angle
indicates the elevation of the solar ray above the
horizontal Earth plane.
profile angle
is an indication of the altitude, but as seen in terms of a
sectional cut that is usually based on a building orientation rather than the
sun or the north-south axis
Heat Flow
heat always flows from warmer to cooler substances.
Heat Gain
total load on a cooling system
Cooling Load
the rate at which heat needs to be removed
Heat Loss
flow of heat from warmer region to a cooler region
Heating Load
the rate at which heat must be added
Internal Load/Gain
combined internal heat loads in a given space
Balance Point Temperature
Tbp = Ttherm - Q i / UA
Ttherm = thermostat setting
Q i = internal gains (people, lights, equipment). Total number of BTUs gained in day
U = material conductance
A = Area
UA = building's heat loss rate per square foot of a building
component (roof, wall, windows)
[ BTU = UA∆T ]
Thermal Transfer
BTUH = Sq.Ft. Area x "U" x ∆T °F
"U" Coefficient = 1 / Total Resistance = 1 / R total
Heat
The energy of vibrating molecules in a substance.
Temperature
the measure of the average vibrating energy in each of the molecules of a substance
Absolute Zero
temperature at which all molecular motion stops
Sensible heat
which relates to temperature change, is heat that
can be sensed and can be measured
measured on a dry bulb thermometer
Latent heat
cannot be sensed since it does not entail any temperature change.
It relates to the energy involved with a change in state or phase change of a
material
calorie
Basic metric unit of heat energy.
Homeostasis
the physiological process of maintaining a constant
deep-body temperature.
Metabolism
the bodily process that converts chemical energy (food) into mechanical energy (activity) and thermal energy (heat).
Conduction
- the transfer of vibrating (thermal) energy between
adjacent molecules
Convection
- As a gas or liquid acquires heat by conduction, the fluid
expands and becomes less dense. It will then rise by floating on top of denser
and cooler fluid.
Radiation
- the process of emitting energy in the form of waves or
particles. It is not affected by gravity. Four material interactions - transmittance, absorptance, reflectance, emittance
Evaporation
- It is the process whereby atoms or molecules in a liquid state gain sufficient energy to enter the gaseous state (vaporization). It is the opposite process of condensation.
Absorption
- Capacity to absorb radiant energy into a material
Reflection
- Capacity of a material to reflect radiant energy
Emittance
- Emissivity of a material is the relative ability of its surface to emit energy by radiation
Transmission
- Capacity to transmit radiant energy through a given material
Direct Gain
Direct solar gain is based on the Solar
Heat Gain Factor (SHGF corrected by a
Shading Coefficient (SC) to adjust solar
gain through single sheet glass) to:
• temperature during the day
• interior design temperature
• hour of the day
BTUH = Area x SHGF x SC
Transmission Gain
Transmission gain is based on the
"U" coefficient of the glass and the
temperature difference,
which depends on:
• maximum ∆T
• type of glass used
• orientation of glazing
• time, both in terms of the time
of year and hour of the day
BTUH = Area x "U" x ΔTACTUAL
vapor barrier
should be installed as close as possible on the the warm side of all thermal barriers
Passive solar heating or cooling
one in which the thermal energy flow is by natural means. Passive systems utilize radiation, conduction or natural convection to distribute energy flow.
Active solar heating or cooling:
Fans or pumps assist in the "forced" distribution of heat.
Active Solar
also refers to the production of electricity through a
conversion of solar energy to electricity through photovoltaic cells
Geo-thermal
Extraction of heat from deep within the earth (uncommon)
Geo-exchange
Use of ground just below the surface as a source of heat in winter and a heat sink in summer.
types of airflow
1. laminar
2. separated
3. turbulent
4. eddy
Refraction
is the bending of light
The apparent speed of light changes
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