energy & atmosphere. 1.sustainable sites 2.water efficiency 3.energy & atmosphere goals...
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Energy & Atmosphere
1. Sustainable Sites2. Water Efficiency3. Energy & Atmosphere
• Goals & Background• Climate Assessment• Building Massing & Orientation• The Building Envelope• Energy Systems• Renewable Energy• LEED NC Prerequisites & Credits
• Intents & Strategies• LEED O&M Prerequisites & Credits
• Intents & Strategies
Session 2: Agenda
What are the goals of Energy & Atmosphere Section?
Energy & Atmosphere: Goals & Background
• Reduce energy consumption• Increase on-site renewable energy generation• Increase market for off-site renewable energy
generation• Reduce ozone layer depletion and global warming
gas generation
The impact of architects and engineers:
The building, industry and transportation sectors are the three sectors that consume energy in the US. Buildings are the largest consumers of energy.
Energy & Atmosphere: Goals & Background
What architects and engineers influence:A reorganization of the data shows that when the energy required to run buildings is combined with the embodied energy of industry-produced materials such as carpet, tile and hardware, architects and engineers are exposed as the hidden polluters.
Energy & Atmosphere: Goals & Background
Energy & Atmosphere: Climate Assessment
MA = 5A
Climate Zones (ASHRAE 90.1):
Energy & Atmosphere: Climate Assessment
Temperature
Also:• Precipitation Wind Speed
Insolation
Thermal Comfort
Natural Ventilation Potential
Relative Humidity
Temp. Insolation
Average day for each month
Jan 1st (1 day)
Energy & Atmosphere: Climate Assessment
Micro-Climate:
• Topography• Soil Types• Vegetation• Bodies of Water• Built Environment & Hardscape
The factors above can all effect temperature,humidity, wind speed, solar heat gain, etc.
Energy & Atmosphere: Climate Assessment
Climate Specific Design:
Hot-Dry:• High thermal mass, small
windows, flat roofs, night ventilation
Hot-Moist:• Low thermal mass, natural
ventilation, roof overhangs
Energy & Atmosphere: Climate Assessment
Climate Specific Design:
Cold:• Highly insulated, south-facing
windows, high volume, low surface area
Temperate:• Well insulated, shade windows in
summer, un-shaded in winter
Strategic massing & orientation reduces energy consumption & allows for increased connection to the natural environment.
Energy & Atmosphere: Building Massing & Orientation
• Linear E-W geometry allows for reduced solar heat gain and glare, and increases opportunities for daylighting.
Soka Bau, Herzog Wessex Water Operation Center, Bennett Architects
Energy & Atmosphere: Building Massing & Orientation
Increased access to natural ventilation and views must be balanced with the fact that very thin floor-plates have an increased surface to volume ratio, increasing heating and cooling loads.
Energy & Atmosphere: Building Envelope
The building envelope:
Energy & Atmosphere: Building Envelope
The building envelope must mitigate many factors, including:
• Precipitation (rain/snow)• Ground Water• Airflow *• Thermal Resistance *• Water Vapor• Solar Heat Gain *• Visible Light *• Views / Access
* These factors directly impact building energy consumption.
Energy & Atmosphere: Building Envelope
What are the elements of the building envelope and what strategies optimize energy performance?
• Airflow• Thermal Resistance• Solar Heat Gain• Visible Light
• Roofs• Walls• Fenestration• Foundations
Energy & Atmosphere: Building Envelope
Unintended airflow (air infiltration) can quickly transfer heat in or out of the building.Air also carries dust and moisture, potentially leading to poor indoor air quality and mold growth. Therefore, the envelope is sealed as tight as possible.
• Airflow• Thermal Resistance• Solar Heat Gain• Visible Light
• Roofs• Walls• Fenestration• Foundations
Energy & Atmosphere: Building Envelope
To stop air flow, materials and assemblies create a barrier to air movement, called an “air barrier”.
• Airflow• Thermal Resistance• Solar Heat Gain• Visible Light
• Roofs• Walls• Fenestration• Foundations
• The air barrier must be a continuous system, accounting for all surfaces and joints.
Energy & Atmosphere: Building Envelope
• Airflow• Thermal Resistance• Solar Heat Gain• Visible Light
• Roofs• Walls• Fenestration• Foundations
Window Air Leakage (AL) is indicated by an air leakage rating expressed as the equivalent cubic feet of air passing through a square foot of window area (cfm/sq ft).
Blower-Door
Smoke Pen
Energy & Atmosphere: Building Envelope
Testing for air leakage is critical.(otherwise leaks can’t readily be seen)
Theatrical Fog
• Airflow• Thermal Resistance• Solar Heat Gain• Visible Light
• Roofs• Walls• Fenestration• Foundations
Energy & Atmosphere: Building Envelope
When carefully planned and controlled, air flow can be used to save energy and increase comfort.
• Airflow• Thermal Resistance• Solar Heat Gain• Visible Light
• Roofs• Walls• Fenestration• Foundations
• Passive ventilation can reduce the time when mechanical systems must provide fresh air and cooling.
solar chimneys(hot-dry climate)
Energy & Atmosphere: Building Envelope
Thermal resistance (R-value) is a measure of how well a material resists heat transfer through conduction.
• Airflow• Thermal Resistance• Solar Heat Gain• Visible Light
• Roofs• Walls• Fenestration• Foundations
• U-value is the inverse of R-value. It measures a material’s ability to transfer heat through conduction.
Energy & Atmosphere: Building Envelope
• Airflow• Thermal Resistance• Solar Heat Gain• Visible Light
• Roofs• Walls• Fenestration• Foundations
R=1/U
Energy & Atmosphere: Building Envelope
• Airflow• Thermal Resistance• Solar Heat Gain• Visible Light
• Roofs• Walls• Fenestration• Foundations
Thermal bridges:
Energy & Atmosphere: Building Envelope
• Airflow• Thermal Resistance• Solar Heat Gain• Visible Light
• Roofs• Walls• Fenestration• Foundations
Infrared Test:
Energy & Atmosphere: Building Envelope
• Airflow• Thermal Resistance• Solar Heat Gain• Visible Light
• Roofs• Walls• Fenestration• Foundations
Insulation:
Board FoamSpray-Foam Mineral WoolCellulose
Energy & Atmosphere: Building Envelope
• Airflow• Thermal Resistance• Solar Heat Gain• Visible Light
• Roofs• Walls• Fenestration• Foundations
Windows are typically the building system with the lowest insulating value.
Energy & Atmosphere: Building Envelope
• Airflow• Thermal Resistance• Solar Heat Gain• Visible Light
• Roofs• Walls• Fenestration• Foundations
Windows are also the building system with the highest solar heat gain.
• Solar Heat Gain Coefficient (SHGC) measures the percent of solar radiation that passes through the window.
Energy & Atmosphere: Building Envelope
• Airflow• Thermal Resistance• Solar Heat Gain• Visible Light
• Roofs• Walls• Fenestration• Foundations
Too much unshaded glazing leads to large cooling loads.
• Minimizing the SHG and providing exterior shading saves energy.
Energy & Atmosphere: Building Envelope
• Airflow• Thermal Resistance• Solar Heat Gain• Visible Light
• Roofs• Walls• Fenestration• Foundations
Similar to airflow, .When carefully planned and controlled, solar heat gain can be used to save energy.
• Passive solar heating can reduce energy consumption in winter.
Energy & Atmosphere: Building Envelope
• Light colored roofs help to reduce heat gain from the sun and reduce the temperature where mechanical cooling systems are often located.
• Roof overhangs can also shade windows below.
• Airflow• Thermal Resistance• Solar Heat Gain• Visible Light
• Roofs• Walls• Fenestration• Foundations
Roofs can also absorb heat from the sun.
Energy & Atmosphere: Building Envelope
• Increasing the VLT, while decreasing the SHGC may reduce energy consumption by
offsetting the need for electrical lighting without increased cooling loads.
• Airflow• Thermal Resistance• Solar Heat Gain• Visible Light
• Roofs• Walls• Fenestration• Foundations
Visible Light Transmittance (VLT) is the percent of visible light that passes through the window.
Energy & Atmosphere: Building Envelope
• Airflow• Thermal Resistance• Solar Heat Gain• Visible Light
• Roofs• Walls• Fenestration• Foundations
To achieve substantial energy savings, the NY Times building optimized the balance between:
• Exterior shading• Window performance• Advanced lighting controls• Automatic interior shades
Energy & Atmosphere: Energy Systems
Energy Systems:
Energy & Atmosphere: Energy Systems
Energy Flow: Primary Fuel Sources
By rotating turbines (direct kinetic energy)
By burning biodegradable waste and rotating turbines By rotating turbines from heat energy (“deep earth”)
By rotating turbines (direct kinetic energy)By converting solar energy to electrical energy (Photovoltaic)By rotating turbines
By “fission reaction” and generating heat to rotate turbines
By burning natural gas and use heat energy to rotate turbines
By burning petroleum and use heat energy to rotate turbines
Energy & Atmosphere: Energy Systems
Energy Flow: Primary Fuel Sources
Energy & Atmosphere: Energy Systems
How is this energy used in buildings?
Mechanic Mechanical Systems
Heating (Air, Domestic Water)Cooling (Air, Chilled Water)Dehumidification (Air)Ventilating (“Breathable air”)
Electrical Systems
Lighting & Daylighting SensorsPlug Loads (Computers, Appliances, etc)Process Loads (Elevators, Refrigeration / Cooking, etc)HVAC Equipment (Motors, Fans, etc)
Energy & Atmosphere: Energy Systems
Mechanical Systems
Heating:- Typically on-site combustion of fuel
or electrical resistance to heat air or water which is used to distribute heat to the space
- Also relates to heating domestic hot water (typically used in showers and sinks)
Standard: ASHRAE 55 (thermal comfort)
Energy & Atmosphere: Energy Systems
Mechanical Systems
Cooling:- Using refrigerant to “pump” heat from inside to the outdoors (A/C).(‘Heat-Pump’ can reverse it’s cycle to pump heat from the outdoors to inside).
Terms: compressor, condenser, heat exchanger, evaporator, cooling coilStandard: ASHRAE 55
(thermal comfort)
Energy & Atmosphere: Energy Systems
Mechanical Systems
Dehumidification:- Used for removing moisture in air for providing comfort.- The cooling coil in the air handling unit typically achieves 2 things:(1) Condensation forms on the cold
surface of the coil, dehumidifying the air.
(2) Air is cooled to required temperature.
Relative Humidity (RH), unit is %
Energy & Atmosphere: Energy Systems
Mechanical SystemsVentilation:- Ventilation is “fresh / breathable air.”- Allow fresh air from outside constantly.- If outside temperature is not comfortable,
either heat or cool the air before it is sent to the space.
- If outside temperature is comfortable, use it to “condition” the space (free!).
Minimum ventilation (fresh air) is required for human occupancy.Ventilation is measured in “Cubic Feet Per Minute” or CFM (I.P. Units).Standard: ASHRAE 62.1 (ventilation)
Energy & Atmosphere: Energy Systems
Electrical SystemsLighting:- Electrical lighting systems consume
energy. - These systems also generate heat that
flows into the space and also inside the ceiling plenum.
- Lighting systems are designed for adequate illuminance (light that falls on the table). Quality of this light is important for color rendering.
Lighting Power Density (LPD) is amount of lighting energy (watts) per SF (I.P. Unit).Standard: ASHRAE / IESNA 90.1
Energy & Atmosphere: Energy Systems
Electrical Systems
Daylighting Sensors:- Daylighting sensors “sense” amount
of lighting and allows switching on / off of electrical lighting.
- Energy savings potential!- Daylighting sensors are low energy
systems (use very little electrical energy).
Illuminance is measured in foot candles.
Energy & Atmosphere: Energy Systems
Electrical Systems
Plug Loads:- Electrical energy consumed by
computers, table lamps, TVs, etc.- Also referred to as “receptacle loads.”- Plug loads generate heat too!- It is important to provide only optimum
number of receptacles (what is required).
Equipment Power Density (EPD) is amount of electrical energy (Watts) per SF (I.P. Unit).
Energy & Atmosphere: Energy Systems
Electrical Systems
Process Loads:- Electrical energy consumed by
vertical transportation systems (elevator, escalators), cooking, refrigeration, etc.
- Process loads are typically 25% of total energy requirement of a building.
- Process loads generate heat too!
Energy & Atmosphere: Electrical Systems
Electrical Systems
HVAC Equipment Loads:- HVAC equipment (motors, fans,
compressor, etc) consume electrical energy.
- These loads generate heat too!
Mechanical SystemsHeatingCoolingDehumidificationVentilating
Electrical SystemsLighting & Daylighting SensorsPlug Loads (Computers, Fans, etc)Process Loads (Elevators, Refrigeration)HVAC Equipment (Motors, Fans, etc)
Energy & Atmosphere: Energy Systems
How do you ensure that these systems are installed and working as designed?
Building Commissioning
(Fundamental & Enhanced)
AND
Measurement & Verification (M&V)
Solar Resource
Energy & Atmosphere: Renewable Energy
Energy & Atmosphere: Renewable Energy
Solar Energy
- Used to generate electricity (using photovoltaics).
- Used to generate heat energy (solar thermal energy for heating water).
Wind Resource
Energy & Atmosphere: Renewable Energy
Energy & Atmosphere: Renewable Energy
Wind Energy
- Used to generate electricity (using blades that rotate turbines).
- Generation is proportional to the cube of the wind speed.
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