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The Three Tiered Philosophy

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Presentation on theme: "The Three Tiered Philosophy"— Presentation transcript:

1 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

2 Passive vs. Active Approach
Passive systems utilize building design to collect, store, and distribute energy

3 Passive vs. Active Approach
Active systems utilize mechanical means to collect, store, and distribute energy

4 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

5 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

6 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

7 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

8 Basic Design Strategies
Too hot for comfort Skin Dominate Loading Avoid the sun Natural ventilation Surface conditions

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

10 Basic Design Strategies
Don’t 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

11 Basic Design Strategies Internal Dominate Load Building
Lighting Lighting Controls Day Lighting Exhaust air energy recovery

12 Class Exercise Prioritizing climate issues

13 Keeping The Heat In Insulation Infiltration

14 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

15 Insulation Law of diminishing return A wall with:
No insulation 4 inch Insulation inch Insulation U x Area x Temp. Diff. .5 x 100 x 40 = 2000 btu/hr x 100 x 40 = 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

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

17 Insulation Installing Insulation

18 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

19 Shading

20 Shading a form generator

21 Shading Must understand solar geometry

22 Shading Must understand solar geometry East / West shading problem

23 Shading Fixed vs Movable shading Devices

24 Shading

25 Glazing

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

27 Glazing Understand solar geometry

28 Glazing Glazing properties Glazing options
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

29 clear Heat absorbing Reflective

30 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.

31 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.

32 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.

33 Lighting Lighting Strategy General lighting Task 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.

34 Daylighting a form generator

35 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.

36 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.

37 Daylighting The Challenges: Using sunlight without over heating
Getting light to the interior of the space South Direct or beam radiation North Diffused radiation

38 Passive Solar Heating

39 Passive Solar Heating

40 Passive Solar Heating

41 Passive Solar Heating

42 Passive Solar Heating

43 Passive Solar Heating

44 Passive Solar Heating

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