ENERGY Flashcards

0
Q

The long direction of the building should be oriented along which axis? Name two reasons.

A

The east-west axis. To minimize the intense East and West solar radiation while taking advantage of the heating potential of south facing surfaces in the winter.

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1
Q

What are the (7) main factors for energy-efficient building orientation?

A

Heat gain, protection from overheating, daylighting, photovoltaic and solar heating panels, use of beneficial cooling breezes, protection from cold winds, and site topography.

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2
Q

Considering slightly lower morning temperatures, you should just slightly orient a building in what direction off of South? And by approx. how many degrees?

A

The long direction pointing south can be slightly to the east, approx. 15°.

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3
Q

In cold climates a building entrance should be located on what side to avoid winter winds?

A

The Leeward side

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4
Q

In temperate climates entrances should be located on what side to make them more inviting and to capitalize on the natural snow – melting affects of the sun?

A

The south side

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5
Q

In hot climates how should you orient the long side of the building and why?

A

The long side can be oriented to catch cooling breezes

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6
Q

Minimizing surface area as a way to conserve energy works best in what kind of climates?

A

Cold climates

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7
Q

Name three advantages of a long rectangular buildings.

A

The long face can be oriented toward the south for solar heating, and to minimize heat again on the east and west. Long, thin buildings also make it easier to utilize daylighting and to capture winds for natural ventilation.

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8
Q

What is an external load dominated building and what are its characteristics?

A

A building whose energy use is determined mainly by heat loss or heat again through the exterior envelope. It has few occupants per-unit area and a small amount of heat game from lighting, equipment, and people. This includes houses, apartments, condominiums, and warehouses.

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9
Q

What is an internal load dominated building and what are some of its characteristics?

A

Hey building his energy use is driven by a high heat again from occupants, lighting, and equipment. Examples include office buildings, hospitals, retail stores, schools, and laboratories.

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10
Q

What side of the building should you place a deciduous tree on?

A

Southside

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11
Q

How close does a row of trees need to be to a building to reduce wind velocity?

A

About 10 times the height of the tree away

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12
Q

What kind of shading device is most commonly best for south facing facades?

A

Moderate overhangs or horizontal louvers

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13
Q

What kind of shading device is most commonly best for east and west facing facades?

A

Vertical louvers

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14
Q

A row of trees of a certain height will reduce the velocity of wind by…

A

30% to 40% at a distance about 5 times the trees

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15
Q

What are 3 preconditions for better earth sheltering?

A
  1. Natural slope to the land (less earth moving)
  2. Granular soil, i.e. Not clay as it doesn’t drain well and can expand with moisture.
  3. Groundwater level must be below the building
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16
Q

What are 3 precautions to take when designing an earth sheltered building?

A
  1. Extra care in waterproofing the underground portions
  2. The insulation you do use must be designed carefully to avoid condensation on inside walls in a humid environment
  3. Plan for adequate ventilation with the fact that there will be less windows
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17
Q

Name 9 pros of a green roof.

A
  1. Conserving energy by reducing cooling and heating loads
  2. Reducing storm runoff
  3. Absorbing carbon dioxide
  4. Reducing ambient air temperatures
  5. Filtering the air and binding dust particles
  6. Reducing heat island effect
  7. Protecting roof from ultraviolet light degradation, temp extremes, wind and hail
  8. Adding acoustical insulation
  9. Aesthetic appeal!
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18
Q

What are the 2 major types of green roofs? Describe.

A

Extensive and intensive. Extensive uses soil less than 6in. for meadow grasses, sedums, herbs perennials. Intensive uses deeper soils and supports complex plantings and shrubs.

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19
Q

6 steps to making a green roof

A
  1. Waterproofing over roof structure
  2. Root barrier (if necessary) placed over the waterproofing
  3. Insulation over the root barrier, helping to keep water in the growth media from taking heat during the winter
  4. Drainage layer.
  5. Filter fabric
  6. Growth medium from 2-12 inches
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20
Q

Green roofs should be sloped between what and what percent?

A

1.5 min, 30 max.

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21
Q

You get a LEED credit if your green covers what percent of the total roof

A

50

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22
Q

A revolving door is a kind of what?

A

An air lock

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23
Q

Very generally, how many years does it take to recover the cost spent on insulation, weatherstripping, and caulking?

A

A few

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24
Q

Name nine types of insulation

A

Fiberglass, mineral wool, polystyrene, polyisocyaanurate, polyurethane, cellulose, cementitious foam, autoclaved aerated concrete, strop panels, straw – bale construction, plastic fiber

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25
Q

Name four types of available insulation in form.

A

Loose fill, batt, rigid foam boards, spray on foam, or included in other construction assemblies like structural insulated panels

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26
Q

Most insulation types require what to be effective?

A

A vapor barrier

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27
Q

What are two things that should not be used in insulation?

A

Chlorofluorocarbons or hydrochlorofluorocarbons

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28
Q

What does superinsulation mean?

A

Superinsulation is the technique of providing higher levels of insulation than would normally be used, sealing cracks, and preventing thermal bridges

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29
Q

What do you sometimes have to do in order to super insulate?

A

Make a thicker wall

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30
Q

What is transparent insulation?

A

A thick layer of polycarbonate honeycomb material, acrylic foam, or fiberglass sandwiched between layers of glazing

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31
Q

What is movable insulation?

A

This is when you remove insulation during sunlight hours and replace it at night or during cloudy weather to prevent heat loss. Typically used on windows. Go down shutters, insulated shades, swinging panels of insulation, expanded polystyrene beads blown between panes of glass.

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32
Q

What are the three awesome things that an air barrier does?

A
  1. Conserves energy by conditioning unwanted infiltrating air until it meets indoor air requirements.
  2. Blocking out infiltrating air which may contain pollutants
  3. Controlling air movement and helping to minimize migration of moisture
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33
Q

What does wind pressure do?

A

Wind pressure puts positive pressure on the windward side of the building and negative pressure at the corners and on the Leeward side.

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34
Q

What is stack pressure?

A

A difference in pressure at the top and bottom of the building due to temperature differences.

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35
Q

What is fan pressure?

A

Fan pressure is the pressure created by an HVAC system

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36
Q

Name five materials that have n low enough air permeability to be used as air barriers

A

Gypsum board, foil-faced urethane insulation, glass, metal, urethane foam, modified bitumous self-adhering membranes, cement board

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37
Q

What is the difference between an air barrier and a vapor barrier?

A

An air barrier is part of the envelope that controls the movement of air in and out. A vapor barrier prevents water from moving out of the building in cold climates and into a building in hot humid climates

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38
Q

What is more effective in moisture/humidity control – an air barrier or a vapor barrier?

A

And air barrier because it can transport hundreds times more water vapor

39
Q

What are the two gases you can put between panes of glass and what is different about them?

A

Argon and krypton. Krypton is about 200 times more expensive than argon but more efficient when the space between glass panes is small.

40
Q

What is low e glass?

A

Double glazing with a thin film or coding placed inside the glazing cavity. The film reflects radiant heat back into the room.

41
Q

What is spectrally selective glazing? And where is it most efficient?

A

Spectrally selective glazing transmits a lot of the visible solar spectrum while blocking heat from the infrared portion. Use it in buildings with a long cooling season that require a lot of light.

42
Q

What is a super window?

A

These windows combine too low E coatings with gas filled cavities between three layers of glass.

43
Q

What is thermochromic glass?

A

It becomes translucent when it gets to a certain temperature

44
Q

What are switchable glazings?

A

They change their characteristics based on particular environmental conditions or through mechanical intervention.

45
Q

Name the three types of switchable glazing.

A

Electrochromic glazing (by electrical input). Photochromic glazing (by the direct action of sunlight). Thermochromic glazing (in response to temperature).

46
Q

Name the thing that makes it possible to have a glazing material switch from transparent to reflective.

A

Transition – metal hydride electrochromic’s. They are based on coatings of nickel-magnesium.

47
Q

How far away are the two glazed layers in a double envelope typically separated by?

A

2 to 3 feet

48
Q

What is a dynamic buffer zone?

A

When a new layer of glazing is built around an existing building, usually built to prevent and control condensation with dry, preheated air during the winter

49
Q

What percentage of energy usage of a typical building does electric lighting and the cooling it requires account for?

A

30 to 40%

50
Q

What is the daylight factor?

A

This is the ratio as a percentage of the illuminance an indoor horizontal plane to the outdoor illuminance of the overcast sky

51
Q

Tell me about the ranges of daylight factors (three types)

A

Under 2 – not adequately lit artificial lighting required
BR 2 and 5 – adequately lit but artificial lighting may be in use for part-time
over 5 - well lit

52
Q

What are three disadvantages of too much daylighting?

A

Too much heat gain or loss, glare, imbalanced lighting

53
Q

Why are taller floor to floor heights better for daylighting?

A

They allow more light to penetrate the interior of the building and leave more room for light shelves

54
Q

How do you like shells affect the effective daylighted zone?

A

They extend the effective daylighted zone from about 1.5 times the window height to about 2 to 2.5 times the window height

55
Q

What does effective aperture define?

A

The variables of light transmittance and window-to-wall ratio

56
Q

What is visible light transmittance?

A

This is the percentage of light that passes through glazing material

57
Q

What is the window-to-wall ratio?

A

The net glazing area in a room or space divided by the gross exterior wall area (not including window frames are millions)

58
Q

What has a high WWR and what has a low WWR?

A

Small punch windows have low WWRs, large continuous windows have high ones

59
Q

What are two cool things that light shelves do other than extend the effective daylit area?

A

They reduce glare and distribute light more evenly to the back of the room

60
Q

What is a good VLT value for glare?

A

50% to 70%

61
Q

What is a good EA value for glare?

A

An EA value of at least .2 or .3 might allow you to reduce the VLT of glass

62
Q

What is more effective at reducing solar heat gain – exterior shading or interior shading?

A

Exterior shading

63
Q

What’s the recommended reflectance for ceilings, walls, and floors respectively?

A

80%, 50% to 70%, 20% to 40%

64
Q

What is a light pipe?

A

Round or square tubes with highly reflective interior coatings that extend from the roof to the space to be lit. Sunlight is captured through a clear plastic dumb, directed to a translucent diffusing plate at the bottom.

65
Q

What percentage of the energy has to be supplied through on-site renewable energy sources in order to get an LEED credit?

A

At least 5% of the buildings total energy use, with additional credits for 10% and even 20%

66
Q

What is the declination angle?

A

This is the relationship between the north-south axis of the earth to the north-south axis of the sun, and it is 23.5°

67
Q

What is the azimuth angle?

A

It’s the compass orientation of the sun, The number of degrees either east or west of due south

68
Q

What is the altitude angle of the sun?

A

The apparent height of the sun in degrees - as measured from the horizon, being 0°, to directly overhead, which is 90°

69
Q

What does passive solar energy really mean?

A

That just means that solar energy is collected stored and distributed without mechanical equipment

70
Q

When talking about passive solar energy, what is a direct gain system?

A

It collects heat through south-facing glass and stores it in high mass materials to be slowly released at night

71
Q

What is a super cool thing to use in a trombe wall and why is it better than concrete or masonry?

A

It’s water! And it’s better because it has a higher specific heat and can store more energy than masonry

72
Q

What is a phase change material and why does it work great for indirect gain systems or trombe walls or green houses?

A

Typically eutectic salts that change from a solid to a liquid at a fairly low temperature so that they store more latent heat while undergoing the phase change from solid to liquid

73
Q

Describe a roof pond

A

Large water–filled bags on the roof of the building that heat up during the day. At night you put insulation over them so that the heat projects into the building.

74
Q

What’s an active solar energy system - very basically?

A

Unlike a passive it uses mechanical equipment to store collect and distribute solar energy

75
Q

What is a convective loop system?

A

A solar collector is below the space so that cool air is circulated by natural convection as the warm air rises and cool air falls back to the collector to be reheated. Convective loop systems are often used to circulate water.

76
Q

What is it called when a type of passive system is used with ductwork and fans to distribute they heated air without relying solely on natural convection?

A

A passive system with active assist

77
Q

Name the three components you need for a typical active solar system.

A

The collector, A storage device, and a distribution system.

78
Q

In an active solar energy system what is a flat–plate collector?

A

A network of pipe locator of sorptive black service with low emissivity below glass or plastic. The pipes carry the heat or transfer fluid.

79
Q

In active solar energy systems what is a focusing collector?

A

A parabolic – a perfect or that focuses the incoming radiation to a single pipe the care is that he does transfer medium.p

80
Q

A typical active solar system uses what kind of storage device for water systems and what kind of storage device for air systems?

A

Water for water, rocks for air

81
Q

What needs to happen for solar energy to be used for cooling?

A

High enough temperatures have to be reached in the transfer medium

82
Q

Why is wind energy generally not appropriate for individual building use?

A

Wind machines are expensive and most jurisdictions won’t allow their use on urban or suburban sites.

83
Q

there are three types of photovoltaic cells in use. Name them and tell me which one is the best.

A

Crystaline, polycrystalline, and thin – film. Crystaline is the most widely used, polycrystalline is cheaper but less powerful

84
Q

What is the ideal angle of a PV array?

A

The latitude of the building plus or minus 15°

85
Q

What is balance-point temperature?

A

Temperature at which a building makes the transition from a heating to a cooling need

86
Q

What is glazing factor?

A

And LEDD based number calculated with window area, floor area, window geometry factor, light transmission, and a window height factor

87
Q

What is ground light?

A

This is visible light from the sun and sky reflected by exterior surfaces below the plane of the Horizon

88
Q

What is net metering?

A

The requirement that utilities pay and charge equal rates regardless of which way electricity flows

89
Q

What is radiative cooling?

A

Collecting heat in thermal mass during the day, releasing it at night

90
Q

What is the shading coefficient?

A

The ratio of solar heat gain through glazing to the solar heat gain through and unshaded 1/8” thick clear double strength glass under the same set of conditions

91
Q

What is solar heat gain coefficient?

A

The ratio of the solar heat gain through fenestration to the total solar radiation incident on the glazing. Includes the effects of the frame and glass spacer. Always a number between 0.0 and 0.87.

92
Q

Heat recovery systems that take the heat from exiting graywater are best in facilities like restaurants, laundries, apartment complexes - places that need a lot of domestic hot water. There are two types. What is a direct system?

A

The graywater flows past a coil of cold water.

93
Q

Heat recovery systems that take the heat from exiting graywater are best in facilities like restaurants, laundries, apartment complexes - places that need a lot of domestic hot water. There are two types. What is a tank system? What are it’s advantages and disadvantages?

A

Graywater is held around coils of incoming cold water. It retracts more heat but requires more maintenance.

94
Q

Names the four phases to an LCA (life cycle assessment)

A
  1. Define the goals and scope
  2. Perform an inventory analysis (calculate the energy and embodied energy of every material)
  3. Perform an impact assessment (on the surrounding environment including health an social welfare)
  4. Perform improvement analysis (report results)