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HOME_NZ
Sustainable Home Design Competition Winner Phoenix, AZ |
Area: 2170SF HERS Score: 30 Estimated Construction Cost: $158/SF |
Taking cues from the legacy of the 1950’s case study homes as well as the ubiquitous sprawling suburban developments, HOME_nz brings together the spatial, material, environmental and renewable energy practices commonly used by the local construction industry to build the city’s growing communities.
Our approach to net-zero design was simple: reduce energy loads! In other words, instead of spending a lot of money on high efficiency equipment and renewable energy systems at the beginning, we spent the effort and resources on a well insulated building envelope, reduced hot water energy loads, desiged for shade at all windows, specified efficient appliances, and many other energy reducing practices. Once the energy was reduced to the minimum, we then implemented high efficiency equipment, followed by renewable energy systems.
Our approach to net-zero design was simple: reduce energy loads! In other words, instead of spending a lot of money on high efficiency equipment and renewable energy systems at the beginning, we spent the effort and resources on a well insulated building envelope, reduced hot water energy loads, desiged for shade at all windows, specified efficient appliances, and many other energy reducing practices. Once the energy was reduced to the minimum, we then implemented high efficiency equipment, followed by renewable energy systems.
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SOLAR
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The design of the photovoltaic (PV) panels are sized to offset the electrical loads from the home. The PV panels are design to be tilted at the most efficient angle for latitude of Phoenix at 33 degrees as well as offset from the roof to allow for heat dissipation. A battery pack system is used in conjunction with the PV panels.
REQUIRED The amount of solar needed for net zero would be 3,750 watts (W), positioned due south, at 33 degree tilt with an assumed inverter efficiency of 98.7% PROVIDED 250 W x 0.85 = 213 W per panel 3,834 W from photovoltaic panels |
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ROOF
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The roof assembly consists of a single ply roofing membrane over tapered rigid polyiso. The white material color will aid in reflecting heat away from the roof.
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WATER COLLECTION
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The perimeter of the roof is designed with an integrated gutter assembly connected to six drop locations where the water can be captured and stored for future landscape irrigation use. Any water that does not use the city resources will indirectly reduce the energy footprint required to treat and transport the water to the home.
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STRUCTURAL FRAMING
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The wall and roof structural assemblies utilize Structural Insulated Panles (SIP) to greatly reduce the conduction of heat through the foam insulated panels as well as the convection of heat through air gaps resulting from construction.
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GLAZING
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A primary concept for the house involved the careful placement of glazing so that the communal spaces contained the most amount of glass. Within the living, kitchen, and dining areas, floor to ceiling height (10’-0”) glazing allow the rooms to expand to the outdoor areas where a protective polypropelene fabric screen prevents 95% of direct sunlight from reaching the glass. Operable windows at the bottom of the window system allow cross ventilation as well as provide the intake for the air to flow up the solar chimney.
The screened and operable windows in each room is carefully placed to encourage cross ventilation as well as providev daylight. |
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INTERIOR
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From the glow of the early morning sunlight to the colorful dusk desert sky, the organization and layout of the interior is designed to allow the residents to enjoy the shifting daylight throughout the day. The design of the clerestory windows within each room takes advantage of the daylight from the full height glazing on the east and west facades.
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SITE
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Although the north-south orientation of the south is not optimally positioned to reduce solar heat gain, the home is designed to prevent much of the direct sunlight from reaching the glazing by utilizing full height fabric screens to provide maximum shade.
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