It is still early in the collection and analysis of energy performance data, but it is already clear that high-performance commercial buildings—some "almost net-zero buildings"—can be constructed cost effectively, providing productive environments for occupants, reducing operating costs, and enhancing the competitiveness of commercial properties.
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This paper describes how net-zero energy buildings will produce, during a typical year, enough renewable energy to offset the energy they consume from the grid.
This conference paper discusses four well-documented definitions of net-zero energy: net-zero site energy, net-zero source energy, net-zero energy costs, and net-zero energy emissions, along with pluses and minuses of each.
This paper reviews the novel procurement, acquisition, and contract process of a large-scale replicable net zero energy (ZEB) office building. The owners (who are also commercial building energy efficiency researchers) developed and implemented an energy performance based design-build process to procure an office building with contractual requirements to meet demand side energy and LEED goals. The key procurement steps needed to ensure achievement of the energy efficiency and ZEB goals using a replicable delivery process are outlined.
This paper documents the methodology developed to identify and reduce plug and process loads (PPLs) as part of NREL's Research Support Facility's (RSF) low energy design process. PPLs, including elevators, kitchen equipment in breakrooms, and office equipment in NREL’s previously occupied office spaces were examined to determine a baseline. This, along with research into the most energy-efficient products and practices, enabled the formulation of a reduction strategy that should yield a 47% reduction in PPLs. The building owner and the design team played equally important roles in developing and implementing opportunities to reduce PPLs. Based on the work done in the RSF, a generalized multistep process has been developed for application to other buildings.
The Research Support Facility at the National Renewable Energy Laboratory (NREL) is a 220,000-ft office building designed to serve 822 occupants, to use 35.1 kBtu/(ft2·yr), to use half the energy of an equivalent minimally code-compliant building, and eventually to produce as much renewable energy annually as it consumes. These goals and their substantiation through simulation were explicitly included in the fixed price design-build contract. The energy model had to be repeatedly updated to match design documents and the final building, as it was built, to the greatest degree practical. Computer modeling played a key role in diagnosing the energy impacts of program and decisions and in verifying that the contractual energy goals would be met within the specified budget. The primary tool used was a whole-building energy simulation program. Other simulation tools were used to provide more detail or to complement the primary tool as required by the delivery schedule, including tools to calculate thermal bridging, daylighting, natural ventilation, data center energy consumption, transpired solar collectors, thermal storage in the crawlspace, and electricity generation by photovoltaic panels. Results were either fed back into the main whole-building energy simulation tool or used to post-process model output to provide the most accurate annual simulations possible. This paper details the models used in the design process and how they informed important program and design decisions from design to completion.
Low energy or high-performance buildings form a vital component in the sustainable future of building design and construction. Rigorous integrated daylighting design and simulation will be critical to their success as energy efficiency becomes a requirement, because electric lighting usually represents a large fraction of the energy consumed. We present the process and tools used to design the lighting systems in the newest building at the National Renewable Energy Laboratory (NREL), the Research Support Facility (RSF). Daylighting had to be integrated with the electric lighting, as low energy use (50% below ASHRAE 90.1-2004) and the LEED daylight credit were contractually required, with a reach goal of being a net-zero energy building (NZEB). The oft-ignored disconnect between lighting simulation and whole-building energy use simulation had to be addressed, as ultimately all simulation efforts had to translate to energy use intensity predictions, design responses, and preconstruction substantiation of the design. We present preliminary data from the postoccupancy monitoring efforts with an eye toward the current efficacy of energy and lighting simulation methodologies.
This paper introduces a classification system for net-zero energy buildings (ZEB) based on the renewable sources a building uses.
First costs, or capital costs, for energy efficiency strategies in office buildings are often a primary barrier to realizing high-performance buildings with 50% or greater energy savings. Historically, the industry has been unable to reach deep energy savings because of a reliance on energy cost savings and simple payback analysis alone to justify investments. A more comprehensive and integrated cost justification and capital cost control approach is needed. By implementing innovative procurement and delivery strategies, integrated design principles and cost tradeoffs, life cycle cost justifications, and streamlined construction methods, first cost barriers can be overcome. It is now possible to attain marketable, high-performance office buildings that achieve LEED Platinum and reach net zero energy goals at competitive whole building first costs, as illustrated by the U.S. Department of Energy’s and National Renewable Energy Laboratory’s latest high-performance office building, the Research Support Facility (RSF) on the National Renewable Energy Laboratory campus in Golden, Colorado.