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A breakdown of technologies and ORNL research in energy efficient buildings technology. 1 Solar panels: Used to heat water via the solar hot water heater and generate electricity, solar helps offset power use by reducing water heating kilowatt hour use and delivering electricity to the grid. The Tennessee Valley Authority pays 15 cents per kilowatt-hour for the solar power. ORNL solar technology projects include the hybrid lighting system, which pipes light through optical fibers into commercial buildings and will convert the remaining solar energy into electricity. Another ORNL solar project aims to integrate the solar panel's inverter with the collector. Contacts: Hybrid solar lighting, Melissa Lapsa; Inverter integration, Mitchell Olszewski 2 Roofing: The Lenoir City homes feature standing seam metal roofs with "cool colored coatings" that reflect infrared rays, reducing the need for air conditioning. ORNL researchers developed and tested these pigments, also used on the homes' sunlight-exposed foundation areas, in collaboration with manufacturers. ORNL strives to improve the longevity of roofing systems from 12 to 30 years, boost energy efficiency by 150% and identify moisture-tolerant materials and environmentally sound roofing practices. Ongoing R&D focuses on affordable approaches to roof-integrated natural ventilation, radiant barriers, the addition of thermal mass through concrete tiles or through phase-change materials and optimized integration of these concepts. An ORNL computer tool that predicts the energy savings for houses with roofs of different colors can be found at ORNL's Building Envelopes Program. Contacts: Bill Miller; Andre Desjarlais 3 Utility wall: Designed at ORNL, this wall consolidates most of the home's hot water plumbing—with the primary bathroom, laundry and kitchen back-to-back— and enables a home energy savings of 15% over a traditionally plumbed house. Contact: Jeff Christian 4 Interior design and ventilation: Near-zero-energy homes are designed to limit ductwork and plumbing lines for most efficient energy use. Building interior walls using metal studs rather than wood is more cost effective and sustainable. Contact: Jeff Christian 5 Exterior walls: To improve the energy efficiency of walls in new construction and renovation, ORNL researchers examine use of exterior insulation finish systems, wall cladding color, thermal mass and air tightness. To achieve affordable energy efficiency and durability, ORNL is investigating passive self-drying wall designs that remove moisture that has either leaked into the wall or permeated the structure by diffusion. ORNL has developed a standardized approach to determining the energy efficiency of entire wall systems, including wall structures, corners, windows and doors. More than 400 walls have been tested in ORNL's Buildings Technology Center. Contact: Achilles Karagiozis; Jan Kosny Heating, cooling, and water heating: Virtually airtight, houses such as the Lenoir City near-zero-energy homes create challenges for behind-the-scenes equipment that must maintain comfortable temperatures and humidity levels and provide hot water when desired. These airtight homes must be ventilated to bring in fresh air, a major source of indoor moisture in humid climates. To be optimally comfortable year-round, homes like these benefit from either a stand-alone dehumidifier or a new kind of heat pump that can provide enhanced dehumidification on-demand. Multiple pieces of equipment used to condition the typical home's air and water lack sufficient integration, wasting energy. For example, the unit for cooling and dehumidification discards heat outdoors while electricity is purchased to heat water in the storage tank. ORNL and industry partners are developing an integrated heat pump that performs all the needed functions through elegant integration with one compressor-bearing unit. Contacts: Van Baxter; Keith Rice; Rick Murphy Structural insulated panels: These make up the walls, floors and roofs of the Lenoir City homes and serve both the structural and insulation requirements, reducing the need for space heating and cooling and enabling contractors to easily build airtight structures. Contact: Jeff Christian 6 Basement: Walls are made of exterior-insulated, termite-resistant, 12-inch reinforced concrete block with 23/16-inch fiberglass drainage insulation board on the exterior and an above-grade waterproof covering. They can be painted with an infrared-reflective coating. The interior basement wall provides thermal mass for the building, more uniform interior comfort, annual energy savings and reduced demand during peak periods. Other low-cost foundation systems being studied may provide energy efficiency, moisture tolerance and pest resistance. Contacts: John Shonder; Moonis Ally 7 Geothermal energy: Ground-coupled heat pumps trump air-source units in energy efficiency because the ground is warmer than outdoor air in winter and cooler in summer. Affordability is an issue because the systems typically require extensive below-ground drilling. Recent experience with the Lenoir City homes indicates that use of well-insulated, airtight envelopes; ductwork within the thermal envelope; the interior utility wall; a thermally massive foundation with exterior insulation and other features can be groundcoupled with no additional excavation beyond that needed to construct the home. Using Lenoir City data, ORNL is developing and validating a tool that can size ground loops limited to installation within construction excavations. Contacts: John Shonder; Moonis Ally
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