engr. david sanchez
DESCRIPTION
Region VIII Conference - Tech. PaperTRANSCRIPT
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Green design concepts
GREEN BUILDING � A green building is a building that has been constructed
or renovated to incorporate design techniques, technologies, and materials that lessen its dependence on fossil fuels and minimize its overall negative environmental impact.
� “Green building” is use to describe a building with minimal site disruption that is energy, water, and resource-efficient; and has good indoor air quality, natural lighting, and acoustics, among other benefits.
GREEN BUILDING � Efficient
� Quality of Life
� Protects the ecosystem
� Improves air and water quality
� Reduce operating cost
� Enhance occoupant comfort
WHOLE
BUILDING
APPROACH
INTEGRATED
DESIGN
PROCESS
Green design concepts
� The Sun and Shading Design
� Passive Design
� Climate analysis
� Lighting Design
� Human comfort
� Thermal analysis
� Acoustic Design
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Why do Green DESIGN � Buildings consume up to
40% of the total energy used
� Sun provides more than 10,000 times the energy we currently use
� Sustainability is ensuring that our actions today does not destroy the opportunities of the future generation.
What we will cover � Passive Design � Passive Cooling
� Natural ventilation � Evaporative cooling � Solar Shading
� Passive Heating � Direct / Indirect gain � Sun Spaces � Trombe wall � Roof Pond
� Daylighting
What we will cover
� Passive Design
and this is the Active way of cooling!!
This is Passive way of cooling…
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Why do Passive DESIGN
� A properly designed passive home can reduce total energy load by up to 40%.
� Passive design concepts are used for heating, cooling and lighting purposes.
� I m p r o v e s c o m f o r t , productivity and health.
Passive design
� Uses only locally available energy source
� Utilizes the natural flow paths of energy
� Address heating, cooling and lighting of spaces
� By induced convection currents, reflected or refracted transmission.
� On site energy sources – solar radiation, air movement from wind and temp difference, biomass, geothermal and hydro.
Basic passive design idea is:
� Bring in daylight, heat and airflow when beneficial and exclude them when not.
� Store ambient energies for later distribution.
� Correct orientation, fenestration and shading
� Efficient envelope, thermal mass
� Renewable energies
Major principles of passive design
� Orientation
� Glazing
� Insulation
� Thermal mass
� Ventilation
� Zoning
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Building orientation
� In warm/hot climates, more east and west glazing will cause more overheating
Existing buildings
Propose site
Glazing
• Use low U value
• Use low-emissivity (low-e) glass
• Double or triple glazing
Thermal mass Materials used in a building to store heat energy
Most effective when facing direct sunlight
CHB, Concrete, stone, brick, etc.
The thermal storage capacity of a material depends on its conductivity, specific heat and density
Ventilation
� Ventilation assist with cooling the building during summer.
� Wind direction and data for the year is necessary for ventilation analysis.
� Natural ventilation removes stale polluted air to maintain indoor air quality
� Night time cooling
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Zoning planning Open floor plan
Frequently used rooms locate on the south side
Infrequently used rooms locate on the north side
use open floor plan
What we will cover
� Passive Design � Passive Cooling � Natural ventilation
Natural Ventilation Cross ventilation
Night cooling
Air stratification
Stack effect
Solar chimney
Wind direction
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Natural ventilation depth of room Rule of thumb: Single sided ventilation Cross ventilation
Natural ventilation Night cooling
• In hot climates, night ventilation can reduce peak air temperatures next day by 1-2° C in typical office.
• Reduces the air-conditioning load.
• Windows and ventilators are left open so the cool air reaches as many surfaces as possible in rooms.
Natural ventilation Air stratification
Buoyancy force causes air in a room to stratify, with warm layers at the top and cooler layers below.
Natural ventilation stack effect
• Stack effect is the movement of air driven by buoyancy force. • Stack effect is greater in taller building because of greater head of cold air.
• The stack effect is greater if the temperature difference is greater.
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Natural ventilation stack effect Natural ventilation solar chimney
• The transparent wall on the sun facing side of the chimney heats the air in the chimney
• The hot air in the chimney rises, drawing cool air through the lower rooms
• Chimney outlet needs to be about two floors above the ceiling of the room.
Natural ventilation solar chimney What we will cover
� Passive Design � Passive Cooling � Natural ventilation � Evaporative cooling
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Evaporative Cooling • Latent heat of vaporisation – water absorbs energy before evaporation.
• environmentally friendly and cost effective in dry areas
• Wind-catchers directs wind to porous pots full of water
Samples of evaporative cooling
What we will cover
� Passive Design � Passive Cooling � Natural ventilation � Evaporative cooling � Solar Shading
Passive cooling - Solar shading
Blocks summer sun
Use sun shading devices
Sun path of the location
Roof overhang, trellises, louvers, awning
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Passive Cooling – Solar Shading What we will cover
� Passive Design � Passive Cooling � Natural ventilation � Evaporative cooling � Solar Shading
� Passive Heating
Solar data Solar data
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Sun path - Latitude Passive solar - sun
� Passive solar is the use of the sun in a building
� Active solar is using sun to produce hot water or electricity.
� PV for electric and solar thermal for hot water
What we will cover
� Passive Design � Passive Cooling � Natural ventilation � Evaporative cooling � Solar Shading
� Passive Heating � Direct / Indirect gain
Solar heating – Direct heat gain
Direct heat gain • For mild to cold climate • Simplest and least expensive • Sun directly heats the living area
Direct heat gain with storage • Thermal mass
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Solar heating – Indirect heat gain
Indirect heat gain with vents • Heat transfer from wall by conduction • No view or direct daylight
What we will cover
� Passive Design � Passive Cooling � Natural ventilation � Evaporative cooling � Solar Shading
� Passive Heating � Direct / Indirect gain � Sun Spaces
Solar heating – sun space Sunspace with storage from wall and floor • Heat transfer by convection • Sunspace may not always be occupied • Night time heat loss is less critical – can be closed off • Insulation needed if used as living space in night time
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What we will cover � Passive Design � Passive Cooling � Natural ventilation � Evaporative cooling � Solar Shading
� Passive Heating � Direct / Indirect gain � Sun Spaces � Trombe wall
Solar heating – Trombe wall Trombe wall – Thick masonry wall with dark absorbing material and faced with a layer of glass • Simple to operate • Provides silence and privacy to spaces • Provides the heat during night time – living and bedrooms. • Cleaning provision between the wall and glass
Reference • Passive solar handbook Introduction to passive solar concepts
• Passive solar industries council, passive solar design strategies: guidelines for home building
• Bre press, Environmental design guide
• Gaisma website, weather data
• US Department of energy, weather data
• Climate consultant