The Three Tiered Philosophy

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The Three Tiered Philosophy
Comfort by mechanical means
Meeting comfort needs passively rather than
relying on power grid Daylighting Ventilation
Passive solar heating Mass cooling
Lower the need for energy through building
design
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Passive vs. Active Approach Passive systems
utilize building design to collect, store, and
distribute energy
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Passive vs. Active Approach Active systems
utilize mechanical means to collect, store, and
distribute energy
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Skin Dominate Loading Cases where the dominate
heat gain / loss are climate driven and the skin
design is critical.

• Dominate loads
• Insulation
• Glass
• Mass color of skin
• infiltration

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Internal Dominate Loading Cases where the
dominate heat gain is driven by internal
conditions.

• Dominate loads
• Lighting
• Occupants
• Equipment
• Core space not affected by outside conditions

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Basic Design Strategies

• Insulation
• Infiltration Control
• Shading
• Glazing
• Ventilation
• Lighting
• Lighting Controls
• Day Lighting

• Evaporative Cooling
• Thermal Mass
• Surface condition
• Passive Solar Heating
• High Efficiency HVAC
• Economizer Cycle
• Exhaust Air Energy Recovery
• HVAC Controls

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Basic Design Strategies
Sub-divide strategies as indicated
Too hot for comfort Skin Dominate
Loading Internal Dominate Loading
Too cold for comfort Skin Dominate
Loading Internal Dominate Loading
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Basic Design Strategies

• Too hot for comfort Skin Dominate Loading
• Avoid the sun
• Natural ventilation
• Surface conditions

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Basic Design Strategies

• Too cold for comfort Skin Dominate Loading
• Keep the heat in
• Passive solar heating
• Compact design reduce skin surface area

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Basic Design Strategies

• Dont assume a strategy is right for every
  building
• A nightclub will not benefit from daylighting
• Buildings located along the expressway may not
  want natural ventilation
• Evaporative cooling is not effective in the south
• Shading is not important in areas dominated by
  overcast skies
• Strategies should be project specific

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Basic Design Strategies Internal Dominate
Load Building

• Lighting
• Lighting Controls
• Day Lighting
• Exhaust air energy recovery

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Class Exercise Prioritizing climate issues
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• Keeping The Heat In
• Insulation
• Infiltration

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Insulation

• Meet energy code requirements for R-value
• Three basic forms
• Rigid foam serious fire hazard
• Blown-in-place - blown around attic
• Fiberglass blankets must remain dry

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Insulation
Law of diminishing return A wall with No
insulation 4 inch Insulation 8 inch
Insulation U x Area x Temp. Diff. .5 x 100 x 40
2000 btu/hr .076 x 100 x 40 304 .041 x
100 x 40 164 reduction of 1700
btu/h reduction of 140 btu/h Blocking air
leaks is more effective than increasing R value
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Insulation

• Installing Insulation
• Install moisture barrier on
  warm side of envelop to
  avoid condensation
  inside
  of the wall
• Install building wrap to
  reduce infiltration

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Insulation
Installing Insulation
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• Infiltration Control
• Infiltration increases with air velocity
• Develop wind buffers
• Trees / land mass / other buildings
• Use windows and doors with better weather
  stripping
• Install building wrap
• Use sealants

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Shading
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Shading a form generator
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• Shading
• Must understand solar geometry

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• Shading
• Must understand solar geometry

East / West shading problem
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• Shading
• Fixed vs Movable shading Devices

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• Shading

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Glazing
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• Glazing for Hot Climate
• Concept - spectrally selective glazing
• Transmits one portion of solar energy and block
  another

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• Glazing
• Understand solar geometry

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• Glazing
• Glazing properties
• U value pertains only to conduction has not
  affect on direct radiation
• SHGC percentage of solar energy allowed through
  the glass
• Glazing options
• Clear single pane high SHGC .90
• Clear insulated glass high SHGC .85
• Heat absorbing (tinted) moderate SHGC .60
• Reflective glass low SHGC .35

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clear
Heat absorbing
Reflective
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• Natural Ventilation
• Cross ventilation
• Controls humidity buildup
• Enhances evaporative cooling
• Introduces fresh air
• Provide openings on opposite sides of the
  building.
• Strategy depends on natural breeze to work.
• Outside air quality may limit the use of natural
  breezes.
• Design enhancements to increase affect.

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• Natural Ventilation
• Stack ventilation
• Concept is based on thermal convection and
  therefore does not require a natural breeze.
• Works best in spaces with high ceilings that
  provide high louvers for heat escape and low
  louvers for incoming cool air.

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• Natural Ventilation
• Night Flushing
• Concept is based on the heat capacity of the
  buildings mass.
• The building mass absorbs heat throughout the
  day.
• Cool night air is circulated through the
  building to cool the mass.
• By morning, the cycle is ready to start over.
• Concept relies on cool nigh air. It is not
  effective when night temperatures remain
  relatively high.

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• Lighting
• Lighting Strategy
• General lighting
• Use low levels of illumination for the general
  area
• Use efficient fixture
• Use affective control system
• Task lighting
• Use higher levels of illumination at work
  stations
• The combined strategies results in a much lower
  watts / sf. figure.

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Daylighting a form generator
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Daylighting
Solar simulation is the best way to evaluate
shading strategies. Photo documentation can be
made for each hour of the day for any day of the
year.
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Daylighting

• South facing glass must
• limit the quantity of light to avoid over
  heating.
• Avoid direct beam radiation reaching the building
  interior. Diffuse the light.

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• Daylighting
• The Challenges
• Using sunlight without over heating
• Getting light to the interior of the space

South Direct or beam radiation
North Diffused radiation
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Passive Solar Heating
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Passive Solar Heating
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Passive Solar Heating
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Passive Solar Heating
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Passive Solar Heating
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Passive Solar Heating
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Passive Solar Heating