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E Tech II: Thermal Comfort_qz2
n/a
20
Architecture
Undergraduate 3
09/20/2011

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Cards

Term
What does ASHRAE stand for?
Definition
American Society of Heating, Refrigeration and Air-Conditioning Engineers
Term
thermal comfort according to ASHRAE
Definition
"condition of mind which expresses satisfaction with the thermal environment"
Term
how heat is dissipated to environment (body heat flow)
Definition
convection, conduction, radiation, evaporation (no heat loss at 98.6F)
Term
4 conditions of environment that affect comfort:
Definition

1. air temperature

2. relative humidity

3. air movement

4. mean radiant temperature

Term
comfort range for AIR TEMP.
Definition

68-78F

(above 98.6F, heat flow reverses and body gains heat)

Term
comfort range for RELATIVE HUMIDITY
Definition

should be above 20% ALL YEAR, MAXIMUM OF 80%

(low humidity can absorb moisture from skin, @ 100% humidity, evaporation stops)

Term
AIR MOVEMENT
Definition

asset in the summer, liability in the winter (wind-chill factor)

affects heat loss rate to both convection and evap.

Term
DRAFT
Definition
undesirable local cooling of the human body by air movement
Term
MEAN RAIDANT TEMP.
Definition
should match air temp. for maximum comfort
Term
PSYCHROMETRIC CHART
Definition
describes combined effect of temperature and its coincident humidity
Term
how to read PSYCHROMETRIC CHART
Definition

to the right: hotter

to the left: cooler

going up: wetter (more humid)

going down: dryer

Term
increase in AIR VELOCITY
Definition
shift comfort zone to the RIGHT
Term
increase in PHYSICAL ACTIVITY
Definition
shift comfort zone to the LEFT
Term
BIO-CLIMATIC CHART
Definition
combines design strategies with psychrometric chart
Term
reading BIO-CLIMATIC CHART
Definition

PASSIVE/ACTIVE SOLAR: low temp and fairly low humidity

CONVENTIONAL AC: high temp and high humidity

INTERNAL GAINS: ok @ 55-68F

HIGH THERMAL MASS: 68-95F, night flush at temp above 95F

Term
wet bulb temp in PSYCHROMETRIC CHART
Definition

(diagonal lines)

this temp. describes the amount of moisture in an air sample

Term
dry-bulb temperature
Definition
ambient air temperature as measured by a standard thermometer
Term
wet-bulb temperature
Definition
measured by a thermometer with a wetted bulb
Term
what happens at 100% relative humidity with dry and wet bulbs?
Definition
they have the same temperature
Term
COMFORT ZONE
Definition

68-78F

20-80% RH

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