• Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

Card Range To Study

through

image

Play button

image

Play button

image

Progress

1/44

Click to flip

Use LEFT and RIGHT arrow keys to navigate between flashcards;

Use UP and DOWN arrow keys to flip the card;

H to show hint;

A reads text to speech;

44 Cards in this Set

  • Front
  • Back
What is a MET?
"One MET (metabolic unit) is the energy produced per unit of surface area by a seated person at rest...the heat produced by a normal adult is about 360 Btu/h (106 W)." (83)
How does the human body respond when it gets too cold?
"If we are too cold...the flow of blood from our core toward the surface of our skin decreases...which reduces evaporation and therefore heat loss." (83)
How does the human body respond when it gets too hot?
"...when we are too hot...blood flow toward the skin surface increases (vasodilation)... The sweat glands greatly increase their secretion... this increases heat loss by evaporation..." (84)
What are the 4 ways the body passes heat to the environment?
4 ways the body passes heat to the environment are:
convection
conduction
radiation
evaporation
(84)
How does the body cool itself by convection?
convection: "air molecules contact our body, absorbing heat." (84)
How does the body cool itself using conduction?
"conduction (we touch cooler surfaces, and heat is transferred)." (84)
How does the body cool itself using radiation?
"radiation (when our skin surface is hotter than other surfaces 'seen' but not touched, heat is radiated to these cooler surfaces...)" (84)
How does the body cool itself using evaporation?
"evaporation (a liquid can only evaporate by removing large quantities of heat from the surface it is leaving.)" (84)
What is a CLO?
"The insulating value of clothing is measured in CLO units. 1 CLO being equivalent to the typical American man's business suit in 1941." (85)
How can CLO be estimated?
"The total CLO of what you are wearing can be estimated by assuming .15 CLO/lb (0.35 CLO/kg) of clothing weight." (85)
How is COMFORT defined?
"A positive definition of comfort is "a feeling of well-being." The more common experience of comfort is simpy a lack of discomfort - thermally of being unconscious of how you are losing heat to your environment." (86)
What is ASHRAE?
ASHRAE: The American Society of Heating, Refrigerating and Air-Conditioning Engineers (internet)
How does ASHRAE define thermal comfort?
ASHRAE defines thermal comfort as "that condition of mind which expresses satisfaction with the thermal environment..." (86)
What are the 3 categories of factors that affect comfort?
"There are three categories of factors that affect comfort:
personal
measurable environmental...
psychological." (86)
What personal factors affect comfort?
"Most personal factors are under your control:
your metabolism...
your clothing...
various adaptations such as migration to a more comfortable place...
drinking or eating warm or cold foods." (86)
What MEASURABLE ENVIRONMENTAL factors affect comfort?
"Measurable environmental factors are the familiar tools of the designer:
air temperature,
surface temperature,
air motion...
humidity." (86)
What PSYCHOLOGICAL factors influence comfort?
"Psychological factors are also familiar designers' tools, but they are difficult to quantify for comfort:
color,
texture,
sound,
light,
movement...
aroma." (86)
Heat transferred by conduction is primarily dependent on ___________,
Heat transferred by conduction is primarily dependent on SURFACE TEMPERATURE. (87)
Heat transferred by convection is primarily dependent on ___________,
Heat transferred by convection is primarily dependent on
AIR TEMPERATURE
AIR MOTION
HUMIDITY (87)
Heat transferred by radiation is primarily dependent on ___________,
Heat transferred by radiation is primarily dependent on SURFACE TEMPERATURE
ORIENTATION TO THE BODY (87)
Heat transferred by evaporation is primarily dependent on ___________,
Heat transferred by evaporation is primarily dependent on
HUMIDITY
AIR MOTION
AIR TEMPERATURE (87)
What is an important skin factor in cold conditions?
"...skin temperature is an important factor in cold conditions..." (87)
What is an important skin factor in hot conditions?
"...skin wettedness (percentage covered by water) is most important in hot conditions." (87)
What are the four environmental parameters that influence thermal comfort or discomfort?
"...thermal comfort or discomfort, is shaped by...
dry-bulb air temperature,
relative humidity,
radiant temperature...
air speed." (89)
What is DRY-BULB TEMPERATURE?
"Dry-bulb (DB) Temperature. DB temperature is the ambient air temperature as measured by a standard thermometer..." (89)
What is OPERATIVE TEMPERATURE?
"Operative Temperature. This is the average of the dry-bulb temperature and the mean radiant temperature (MRT)." (89)
What is WET-BULB TEMPERATURE?
"Wet-bulb (WB) Temperature. WB temperature is measured by a thermometer with a wetted bulb rotated rapidly in the air to cause evaporation of its moisture..." (89-90)
What is WET-BULB DEPRESSION?
"wet-bulb depression (the difference between DB and WB temperatures)." (90)
How is wet-bulb depression related to relative humidity?
"A large depression is indicative of low relative humidity (RH). Slow evaporation, as when the air is already moisture-laden, results in a small wet-bulb depression and indicates high RH. Note that at 100% RH, DB and WB temperatures are equal." (90)
What is RELATIVE HUMIDITY?
"Relative humidity may be measured directly or derived from DB and WB temperatures...
is the ratio of the actual density of water vapor in air to the maximum density of water vapor that such air could contain, at the same temperature, if it were 100% saturated." (90)
What is MEAN RADIAN TEMPERATURE?
"Mean Radiant Temperature (MRT)... is defined as 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 non-uniform enclosure...cannot be directly measured..." (90)
What areas of the body are most thermally sensitive?
"We are most thermally receptive in these places:
Heat receptors:
fingertips,
nose,
elbows

Cold receptors:
upper lip,
nose,
chin,
chest,
fingers" (94)
Why do some surfaces FEEL warmer or cooler than others even though they may have the same surface temperature?
Because the skin perceives the rate at which heat is being conducted away from the body,a surface with higher conductivity will draw heat away from the body at a faster rate, thus seeming to be cooler and vice-versa. (95)
What is the definition of DRAFT?
"Excessive air motion is called a draft and results in undesirable cooling of the body." (95)
What is CROSS-VENTILATION?
"Cross-ventilation is driven by wind and is accomplished with windows. It relies upon rather narrow plans with large ventilation openings on either side. Thus, it is naturally compatible with daylighting." (101)
What is STACK VENTILATION?
"Stack ventilation depends upon very low openings to admit outside air and very high openings to exhaust air; it is driven by the principle that hot air rises." (101)
What are some HIGH-MASS COOLING strategies?
Some high-mass cooling strategies are:
using the thermal mass of the building itself to absorb heat during the day and then reject that heat into a sink during the night.
roof ponds for one and two-story buildings.
using earth contact as a heat sink. (101)
What is the general concept of HIGH-MASS COOLING WITH VENTILATION?
the general concept of HIGH-MASS COOLING WITH VENTILATION is:
"The building switches from a thermally closed condition by day (to exclude sun and hot outdoor air) to an open condition at night (to allow ventilation to cool the mass). Note: night-time temperatures must be cooler than the comfort zone if this strategy is to be effective." (101)
What is the EVAPORATIVE COOLING design strategy?
The EVAPORATIVE COOLING design strategy "relies on the principle that when moisture is added to the air, relative humidity increases while dry-bulb temperature decreases." (101)
What are some DESIGN STRATEGIES FOR COOLING?
Some DESIGN STRATEGIES FOR COOLING are:
(a) Natural Ventilation Cooling
(b) High-Mass Cooling
(c) High-Mass Cooling with Night Ventilation
(d) Evaporative Cooling
What are the three SOLAR HEATING STRATEGIES?
The three SOLAR HEATING STRATEGIES are:
indirect gain
direct gain
isolated gain (105)
What is solar DIRECT GAIN?
"direct gain (DG)...let sunlight into the space, where it warms exposed thermally massive surfaces..." (105)
What is solar INDIRECT GAIN?
"indirect gain (TW for Trombe wall)...sun strikes the thermal mass first and is then passed only as heat to the space behind..." (105)
What is solar ISOLATED GAIN?
"isolated gain SS (for sunspace) ...a sunspace or greenhouse heated greatly by the sun that then passes some of its heat to the space behind..." (105)