Presentation on theme: "The Three Tiered Philosophy"— Presentation transcript:
1The Three Tiered Philosophy Comfort by mechanical meansMeeting comfort needs passively rather than relying on power gridDaylighting Ventilation Passive solar heating Mass coolingLower the need for energy through building design
2Passive vs. Active Approach Passive systems utilize building design to collect, store, and distribute energy
3Passive vs. Active Approach Active systems utilize mechanical means to collect, store, and distribute energy
4Skin Dominate LoadingCases where the dominate heat gain / loss are climate driven and the skin design is critical.Dominate loadsInsulationGlassMass & color of skininfiltration
5Internal Dominate Loading Cases where the dominate heat gain is driven by internal conditions.Dominate loadsLightingOccupantsEquipmentCore space not affected by outside conditions
6Basic Design Strategies InsulationInfiltration ControlShadingGlazingVentilationLightingLighting ControlsDay LightingEvaporative CoolingThermal MassSurface conditionPassive Solar HeatingHigh Efficiency HVACEconomizer CycleExhaust Air Energy RecoveryHVAC Controls
7Basic Design Strategies Sub-divide strategies as indicatedToo hot for comfort Skin Dominate LoadingInternal Dominate LoadingToo cold for comfort Skin Dominate LoadingInternal Dominate Loading
8Basic Design Strategies Too hot for comfort Skin Dominate LoadingAvoid the sunNatural ventilationSurface conditions
9Basic Design Strategies Too cold for comfort Skin Dominate LoadingKeep the heat inPassive solar heatingCompact design reduce skin surface area
10Basic Design Strategies Don’t assume a strategy is right for every buildingA nightclub will not benefit from daylightingBuildings located along the expressway may not want natural ventilationEvaporative cooling is not effective in the southShading is not important in areas dominated by overcast skiesStrategies should be project specific
11Basic Design Strategies Internal Dominate Load Building LightingLighting ControlsDay LightingExhaust air energy recovery
14Insulation Meet energy code requirements for R-value Three basic forms Rigid foam – serious fire hazardBlown-in-place - blown around atticFiberglass blankets – must remain dry
15Insulation Law of diminishing return A wall with: No insulation 4 inch Insulation inch InsulationU x Area x Temp. Diff..5 x 100 x 40 = 2000 btu/hr x 100 x 40 = x 100 x 40 = 164reduction of 1700 btu/h reduction of 140 btu/hBlocking air leaks is more effective than increasing R value
16Insulation Installing Insulation Install moisture barrier on warm side of envelop to avoid condensation inside of the wallInstall building wrap to reduce infiltration
18Infiltration Control Infiltration increases with air velocity Develop wind buffersTrees / land mass / other buildingsUse windows and doors with better weather strippingInstall building wrapUse sealants
28Glazing Glazing properties Glazing options U value – pertains only to conduction – has not affect on direct radiationSHGC – percentage of solar energy allowed through the glassGlazing optionsClear single pane high SHGC .90Clear insulated glass high SHGC .85Heat absorbing (tinted) moderate SHGC .60Reflective glass low SHGC .35
30Natural Ventilation Cross ventilation Controls humidity buildup Enhances evaporative coolingIntroduces fresh airProvide 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.
31Natural 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.
32Natural 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.
33Lighting Lighting Strategy General lighting Task lighting Use low levels of illumination for the general areaUse efficient fixtureUse affective control systemTask lightingUse higher levels of illumination at work stationsThe combined strategies results in a much lower watts / sf. figure.