Paul Torcellini

U.S. Department of Energy commercial reference building models of the national building stock

The U.S. Department of Energy (DOE) Building Technologies Program has set the aggressive goal of producing marketable net-zero energy buildings by 2025. This goal will require collaboration between the DOE laboratories and the building industry. We developed standard or reference energy models for the most common commercial buildings to serve as starting points for energy efficiency research. These models represent fairly realistic buildings and typical construction practices. Fifteen commercial building types and one multifamily residential building were determined by consensus between DOE, the National Renewable Energy Laboratory, Pacific Northwest National Laboratory, and Lawrence Berkeley National Laboratory, and represent approximately two-thirds of the commercial building stock.

Net-Zero Energy Buildings: A Classification System Based on Renewable Energy Supply Options

NOTICE This report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof. Executive Summary A net-zero energy building (NZEB) is a residential or commercial building with greatly reduced energy needs. In such a building, efficiency gains have been made such that the balance of energy needs can be supplied with renewable energy technologies. Past work has developed a common NZEB definition system, consisting of four well-documented definitions, to improve the understanding of what net-zero energy means. For this paper, we created a classification system for NZEBs based on the renewable sources a building uses. A building that offsets all its energy use from renewable resources that are available within the footprint is at the top of the NZEB classification system at an NZEB:A. A building that achieves an NZEB definition through a combination of on-site renenewables and off-site purchases of renewable energy credits is placed at the lowest end of the NZEB classification at an NZEB:D. We also look at how this classification relates to the previously developed NZEB definitions. The goal of this type of classification is to encourage NZEB owners and NZEB designers to first use all possible cost-effective energy efficiency strategies, and then use renewable sources and technologies that are located on the building and at the site. We have provided for lower classes of NZEB to include buildings whose energy use exceeds the renewable energy available at the site. This NZEB classification system is applicable to both single building projects as well as a set of buildings in a community or campus.

Assessment of the Technical Potential for Achieving Net Zero-Energy Buildings in the Commercial Sector

This report summarizes the findings from research conducted at NREL to assess the technical potential for zero-energy building technologies and practices to reduce the impact of commercial buildings on the U.S. energy system. Commercial buildings currently account for 18% of annual U.S. energy consumption, and energy use is growing along with overall floor area. Reducing the energy use of this sector will require aggressive research goals and rapid implementation of the research results.

Main Street Net-Zero Energy Buildings: The Zero Energy Method in Concept and Practice

Ongoing work at the National Renewable Energy Laboratory indicates that net-zero energy building (NZEB) status is both achievable and repeatable today. This paper presents a definition framework for classifying NZEBs and a real-life example that demonstrates how a large-scale office building can cost-effectively achieve net-zero energy.

General Merchandise 50% Energy Savings Technical Support Document

This report documents technical analysis for medium-box general merchandise stores aimed at providing design guidance that achieves whole-building energy savings of at least 50% over ASHRAE Standard 90.1-2004.

Grocery Store 50% Energy Savings Technical Support Document

This report documents technical analysis for grocery stores aimed at providing design guidance that achieves whole-building energy savings of at least 50% over ASHRAE Standard 90.1-2004.

Evaluation of the Low-Energy Design Process and Energy Performance of the Zion National Park Visitor Center: Preprint

In line with the mission of the National Park Service, the Zion National Park Visitor Center was designed to use 70% less energy than a comparable visitor center built to Federal Energy Code 10 CFR 435 (DOE 1995). The authors and NFS staff used an integrated design process, including extensive simulations, to minimize the energy consumption. The result was a passive solar commercial building that has a good thermal envelope, daylighting, and natural ventilation. Passive downdraft cooltowers provide all the cooling. Two Trombe walls provide a significant amount of the heating. After two years of metering, the results show a net energy use intensity of 24.7 kBtu/ft2 (280.5 MJ/m 2 ) and a 67% energy cost saving. Low energy use and aggressive demand management result in an energy cost intensity of

A pathway for net-zero energy buildings: creating a case for zero cost increase

0.43/ft 2 (

The Van Geet Off-Grid Home: An Integrated Approach to Energy Savings

4.63/m 2 ). The paper discusses lessons learned related to the design process, daylighting, PV system, and HVAC system.

Design and Performance of the Van Geet Off-Grid Home

To have market relevance and gain widespread market adoption, zero energy buildings (ZEBs) will need to be designed and constructed cost-effectively, and preferably without additional costs. An approach was developed to create low-energy buildings without additional construction costs such that it yielded innovation in building technology and integration by the market. A case study of the implementation of this method is presented to provide a data point that ZEBs can be built with zero cost increase. Documenting cost-control best practices and packaging those strategies for adoption by the commercial building sector will help make the business case for ZEBs for mainstream construction and promote market uptake of the innovative technologies and design approaches needed. The holistic implementation of cost-control strategies will enable ZEBs to be designed and constructed on a typical budget. The current state of ZEB economics is evaluated and a path forward is proposed for greater market penetration of ZEBs. By demonstrating how to combine ZEB technologies and design approaches into an overall efficiency package that can be implemented at minimal (zero, in certain cases) incremental capital cost, the domain of ZEB design and construction can be expanded from a niche market to the commercial construction mainstream.