Wednesday, August 19, 2009

An Earth Sheltered Net Zero House Sketch, an unbuilt project

  • So often we're inspired by nature and the earth. Here's a sketch from last year where I was exploring a south facing hillside site with a lifted and separated curving green roof. The house would be a two bedroom, two bath residence with an open and interconnected kitchen, dining living space with three distinct zones having an great room feel. It would hopefully be a net zero home, a residence which produces the same or more energy than it consumes.
  • The living areas fronts the building volume with easy access to the continous arbor covered terrace and ample views to the surroundings. The amount of glazing must be carefully studied through energy modeling. Overglazing would result in potentially over-heating the house and having to size up the airconditioning system at a higher cost and energy use.
  • The glu lam ribs of the home are akin to bones. The residence transitions from the solidity and darkness found within the earth to the lightness of a forest canopy along the continuous south facing porch. An overhead arbor with solar control helps minimize summer glare while providing a place for vines to grow over time. Solar trackers in a solar orchard are just a short walk away. Key bedrooms are organized on the ends of the rectangular volume with view windows to the outside. Interior spaces such as bathrooms are lit from overhead toplighting from triple insulated prismatic skylights.
  • The building enclosure would be super-insulated done in any number of manners suitable to the local climate and building tradititons. It would follow the (R5/R10/R20/R40/R60) for windows, below slabs, walls in below grade conditions, walls above grade and the ceiling as recommended by Joe Lstiburek, Ph.D., P.Eng. of Building Science Corporation. The windows would be triple insulated glazing with low-e argon filled units with thermal spacers set within fiberglas frames. The doors would be fiberglas frames as well to help reduce thermal bridging. The green roof could be extensive or intensive depending on clients desires and structural capabilities, cost, desire to care for the plantings etc. Agressive air-sealing standards would be followed to further reduce energy loads through minimizing energy loss through cracks and joints.
  • Heating would be delivered through a radiant slab. Cooling would be from strategically placed mini-split units. A back-up boiler would be fueled by bio-mass stored in a small silo or cord wood logs.
  • The exterior siding could be hardi-plank, cedar or metal siding such as metal panels, corrugated metal, 12" ribbed siding. The concrete floor would be polished concrete with artistic flourishes involving scattered stones and objects thrown into the slab and polished over to yield exciting, uniquely memorable artful surprises.
  • Interior finishes would be simple, restrained such as using locally milled rough sawn lumber or if a more refined look is desired, finished hardwood standing and running trim of a contempoary nature. Door and kitchen hardware and pulls would be simple rubbed bronze. Paints would be no or low-Volatile Organice Compounds (VOC)
  • Appliances would be high performance energy star models to reduce energy use.
  • Lighting would be high-performance flourescent designer fixtures and a mix of LED lighting where sensible.

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