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Flashcards in test 1 Deck (66):
1

hot and dry climate design

massive walls (time-lag effect), small windows, light colors

2

hot and humid climate design

MOVING AIR AND EVAPORATIVE COOLING:
large windows, large overhangs, shutters, light colored walls, high colored ceilings

3

mild overcast climates (PNW) design

open up to capture daylight: bay windows

4

cold climate design

HEAT RETENTION:
very compact, minimize surface to volume ratio, landforms, few windows, low ceilings

5

parasol roof

umbrella-like structure covering a building

6

sensible heat

measure of random molecular movement or heat - function of temperature and mass

7

latent heat

measure of heat in a change of state

8

heat of fusion (latent heat)

solid --> liquid

9

heat of vaporization (latent heat)

liquid --> gas

10

temperature

a measure of heat (energy)
freezing: 32F, 0C
boil: 212F, 100C
Absolute zero: 0K, -273C, -459F

11

BTU (british thermal unit)

heat required to elevation 1 pound of water 1F at 1atm
approx. 252 calories

12

calorie or Joule

heat required to elevate 1 gram of water 1C

13

Calorie

dietary calorie

14

evaporative cooling

cooling resulting from conversion of sensible heat into latent heat (heat of vaporization)

15

1st law of thermodynamics

law of conservation of energy - finite amount of energy in the universe, energy cannot be created or destroyed

16

2nd law of thermodynamics

heat always moves from higher concentration to lower concentration

17

convection

heat transfer from movement of air

18

conduction

heat transfer from direct contact

19

radiation

heat based on electromagnetic radiation

20

conductivity

heat flow through 1sqft solid that is 1in thick
"k"

21

conductance

heat flow through 1sqft solid of a determined thickness
"C"

22

resistance

reciprocal of either conductivity "k" or conductance "C"
thermal resistance "R" tells effectiveness of thermal insulator
R (per inch) = 1/k or R (total) = 1/C
Greater "R" greater insulator

23

thermal transmittance

"U" - U = 1/ER (Heat flow coefficient)

24

mean radiant temperature

average temp of the radiant environment at a particular point in space
MRT = E (radiant temp)(angle of exposure)/360

25

specific heat

heat required to elevate a material 1 degree (mass)

26

heat capacity

heat required to elevate a material 1 degree (volumetric)

27

green house effect

building scale: short wave infrared enters building through glazing and re-radiates long-wave

global scale: transparent short wave infrared hits the earth and re-radiates long wave that is trapped by layers of greenhouse gases

28

solar constant

the amount and composition solar radiation reaching the outer edge of the earths atmosphere

29

axial tilt of the earth

23.5 degrees

30

summer solstice and winter solstice

June 21 and December 21

31

latitude of tropic of cancer and tropic of capricorn

23.5 N and 23.5 S

32

spring and fall equinox dates

march 21 and september 21

33

altitude angle

vertical angle at which the suns rays strike the earth
alt angle = 90 degrees - latitude

34

sky dome

summer solstice - highest and longest sun path
winter solstice - lowest and shortest sun path
equinox - middle

35

azimuth

measured in a horizontal plane (from north south line)

36

hypothermia

excessive heat loss

37

hyperthermia

insufficient heat loss

38

metabolic rate

to maintain thermal equilibrium, our bodies must lose heat at the same rate at which the metabolic rate produces

39

conditions of thermal comfort

air temperature
humidity
air velocity
mean radiant temperature

40

air temperature (thermal comfort)

68F in winter
78F in summer

41

relative humidity (thermal comfort)

RH should be above 20% all year
below 60% in summer
below 80% in winter

42

air velocity (thermal comfort)

20 - 60 feet per minute

43

mean radiant temperature (thermal comfort)

average skin and clothing temp is around 85F
maintain MRT close to ambient air temp

44

shifts in comfort zone

high MRT - down and to the left
high air velocity - up and to the right
increased physical activity - down to the left

45

macroclimate

climatic region

46

microclimate

a local climate differing from the climatic region it is in

47

what affects a microclimate

elevation above sea level - steeper the slope the faster the temp will drop
form of land - south facing slopes are warmer
size, shape, and proximity of bodies of water
soil types
vegetation
man-made structures

48

degree days

indicates the severity of winter and summer

49

Heating Degree Days (HDDs)

more than 5500 HDD per year = long cold winter
less than 2000 HDD per year = mild winters

50

Cooling Degree Days (CDDs)

more than 1500 per year = long hot summer
less than 500 = mild summers

51

passive solar techniques on vernacular buildings

"salt box" - south facing windows, long roof on north side to deflect winter winds

52

passive solar

system that collects, stores, and redistributes solar energy without use of fans, pumps, or controllers
use basic building elements such as windows, floors, walls, heat-radiating elements

53

passive solar systems

direct gain
trombe wall
sun space

54

direct gain system

south facing windows and thermal mass

55

thermal storage (passive systems)

structural insulated panels, insulated masonry system, trombe wall

56

sun space design

desired because of heating efficiency and amenities
slope of glazing, area of glazing, vent size, thermal mass size

57

shading techniques on vernacular buildings

hot and humid climate: large windows (operable) and overhangs
types: verandah, balcony, loggia, gallery, arcade, engawa

58

types of fixed shading devices

overhang
overhang (horizontal panels)
overhang (horizontal panels in vertical plane)
overhang (vertical panel)
vertical fins
slanted vertical fins
egg crate
egg crate with slanted fins

59

types of movable shading devices

awning
rotating horizontal louvers
rotating fins
egg crate - rotating horizontal louvers
plants
roller shade

60

envelope dominated building

large surface area to volume ratio
affected by climate
tend to have longer overheated periods

61

internally dominated building

compact, small surface area to volume ratio
large internal heat gain from machines, lights, people

62

solar heat gain coefficient (SHGC)

measure of how much solar radiation enters a window (measured between 0.0 - 1.0; 0.0 being no radiation through the window)

63

types of passive cooling systems

comfort ventilation
night flash cooling
radiant cooling
evaporative cooling

64

comfort ventilation

brings outdoor air, esp in daytime when temperatures are highest - air is passed directly over people to increase evaporative cooling on skin
uses operable windows (20%), attic fans

65

radiant cooling

objects emit and absorb radiant energy - objects cool by radiation if the net flow is outward
clear skies, low humidity, one-story buildings

66

evaporative cooling

draws a large amount of sensible heat from surroundings and converts into latent heat in form of water vapor