chapter 10 conservation and environmental design and construction
TRANSCRIPT
Chapter 10
Conservation and Environmental Design and
Construction
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Links for Chapter 10
Energy-Efficiency Design
Solar Energy Design
Passive Solar Systems
Active Solar Systems
Related Web Sites
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Energy-Efficient Design
• Environmentally friendly relates to materials that are recycled, from managed farms or earthen materials
• Be sure to use non-toxic and low-toxic materials for safer buildings
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Energy-Efficient Design
• Goals of environmental programs– Conserve natural resources
– Preserve the earth’s ozone layer
– Create a healthier living environment
– Make housing more economical
– Find better building materials and construction methods
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Energy Codes
• The purpose of code is to regulate the design and construction of exterior and interior materials and equipment
• Exterior envelope is made up of elements of a building that enclose conditioned spaces through which thermal energy transfers to or from the exterior
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Energy-Efficient Construction
• Caulking - Filling in small seams or joints to reduce air drafts
• Vapor Retarders - Designed to keep exterior moisture from the walls and insulation– Most codes require 6-mil plastic over earth
– All seams must be lapped and sealed
– Air-to-air exchanger needed for air circulation
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Energy-Efficient Construction
• Radiant Barriers - Reduce attic temperatures by stopping heat from radiating through the attic
• Insulation - Saves energy costs and makes home temperature more comfortable by reducing air infiltration and heat loss
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Insulation
• Thermal Resistance - The ability of materials to slow heat transfer and measured as R-value– R-30 for ceiling
– R-19 for floors
– R-11 to R-19 for walls
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Types of Insulation
• Loose-Fill - Normally made of fibers or granules and blown into cavities and areas
• Batts and Blanket - Strips of insulation made of fiberglass or cotton fibers
• Rigid Insulation - Fibrous or plastic foam sheets of varying thicknesses
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Types of Insulation
• Foam-in-Place - A spray-in foam with a high R-value made of lcynene
• Insulated Windows - Using a gas or insulated glass to increase the R-value– Argon - Colorless and odorless gas
– Low-E - A transparent coating on the glass
– Rated with a U-value (1/U = R)
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Energy-Efficient Construction
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Solar Energy Design• Using sunlight to produce useful heat energy• Passive solar uses no mechanical devices to
retain, store, and radiate solar heat• Active solar uses mechanical devices to
absorb, store, and use solar heat• Be sure to check local codes before designing
any solar unit in a building
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Roof Overhang
• Winter sunlight that is lower in the sky helps warm the home
• Summer sunlight is blocked from entering the glass and creating solar energy
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Passive Solar Systems
• Solar rays enter the house and are absorbed in structural mass during the day and then released at night
• Materials may include:– Metal — Concrete
– Water — Masonry
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Passive Solar Systems
• South Facing Glass - Heat created directly by sun– Clerestory windows provide
light and heat to second floor
– Skylights are placed on the south slope of the roof and assist in warming in winter
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Passive Solar Systems• Thermal Storage Walls - Walls
constructed of heat-absorbing material– Trombe wall is installed a few inches
from a south wall and heat is pushed up with cool air from below
– Dark water-filled drums are heated with sunlight during the day and heat is released at night
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Passive Solar Systems• Roof Ponds - Containers filled with
antifreeze are placed on a flat roof– Insulation allows the heated antifreeze to
radiate to the living space• Solarium - A room placed on the south
side of the house that warms during the day– The walls are made of glass
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Passive Solar Systems• Envelope Design - A continuous cavity is built around the perimeter of the house
– Solarium is built on the south side– In the winter this warm air rises– In the summer the envelope can cool the house but trees are used to assist
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Envelope Design
Winter Envelope Summer Envelope
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Active Solar System
• Solar collectors are used to convert sunlight into heat by warming a fluid
• Backup systems are required if there is a lack of sunlight
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Active Solar System
• Solar Collectors - Sunlight is caught and turned into heat– Collectors are designed to follow the sun’s
path and improve efficiency
• Storage - Water, rock, or chemicals are used to store the excess heat when it is not needed
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Active Solar System
• Geothermal Systems - Water from the ground is circulated through the house to warm and cool– Closed-loop systems use a fluid pumped
through polyethylene tubes
– Open-loop systems use water pumped from a well or reservoir
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Active Solar System
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Active Solar System
• Photovoltaic Modules - Electricity is produced by sunlight– “photo” means light and “voltaic” means “to
produce electricity by chemical action
– Both AC and DC electricity is produced
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Active Solar System
• Wind Energy - Turbines are turned caused by wind created by unequal heating of the earth
• Hydroelectric Power - Energy is converted from falling water into electricity
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Related Web Sites
• Alliance to Save Energy - www.ase.org
• U.S. Department of Energy - www.doe.gov
• OSI Sealants Inc - www.osisealants.com
• Sustainable Energy - www.solstice.crest.org
• U.S. Green Building Council - http://www.usgbc.org/