Joshua D. Kneifel

Energy performance sensitivity of a net-zero energy home to design and use specifications

The purpose of this report is to test the sensitivity of the energy performance of the National Institute of Standards and Technology (NIST)s Net Zero Energy Residential Test Facility (NZERTF) design to variation in the assumed specifications of occupant behaviour and building design characteristics using whole building energy simulations. The analysis includes a total of 128 EnergyPlus (E+) simulations (DOE 2013) considering two levels for each of the seven factors that could impact the energy performance of the NZERTF: building design, air leakage, occupant behaviour, weather, building orientation, and heating and cooling setpoint temperatures. The results for each combination of the seven factors are analysed to determine the magnitude and significance of changing these factors, and the interaction effects between the factors. There is particular focus on the building design results to determine if the energy performance of the NZERTF is more or less stable than that of typical residential construction in Maryland.

An exploration of the relationship between improvements in energy efficiency and life-cycle energy and carbon emissions using the BIRDS low-energy residential database

To conduct a more complete analysis of low-energy and net-zero energy buildings that considers both the operating and embodied energy/emissions, members of the building community look to life-cycle assessment (LCA) methods. This paper examines differences in the relative impacts of cost-optimal energy efficiency measure combinations depicting residential buildings up to and beyond net-zero energy consumption on operating and embodied flows using data from the Building Industry Reporting and Design for Sustainability (BIRDS) Low-Energy Residential Database. Results indicate that net-zero performance leads to a large increase in embodied flows (over 40%) that offsets some of the reductions in operational flows, but overall life-cycle flows are still reduced by over 60% relative to the state energy code. Overall, building designs beyond net-zero performance can partially offset embodied flows with negative operational flows by replacing traditional electricity generation with solar production, but would require an additional 8.34 kW (18.54 kW in total) of due south facing solar PV to reach net-zero total life-cycle flows. Such a system would meet over 239% of operational consumption of the most energy efficient design considered in this study and over 116% of a state code-compliant building design in its initial year of operation.

Life–Cycle Cost Implications of More Stringent State Energy Codes

Energy efficiency requirements in energy codes vary across states, with states having adopted energy codes ranging across editions of the industry consensus standard (ASHRAE 90.1). Some states do not have a code requirement for energy efficiency, leaving it up to the locality or jurisdiction to set its own requirements. This paper uses ASTM building economic standards (E917-05(2010) and E1074-09) to estimate the impacts that the adoption of more stringent energy codes for commercial buildings would have on building life-cycle costs. The results are based on analysis of the Building Industry Reporting and Design for Sustainability (BIRDS) database. For this study, the performance of buildings designed to meet current state energy codes is compared to their performance when meeting a “Low Energy Case” (LEC) building design based on ASHRAE 189.1-2009, which increases energy efficiency beyond the ASHRAE 90.1-2007 design, to determine whether more stringent energy standard editions are life-cycle cost-effective in reducing energy consumption. The approach is described in detail for a single city and building type (Knoxville, TN). Using the same approach, the new savings for each building type in all cities for Tennessee are calculated. The estimated average savings for each of the building types are aggregated using state-level new commercial building construction data to calculate the magnitude of the net savings (80.8 GWh annually and

Building Industry Reporting and Design for Sustainability (BIRDS) Building Code-Based Residential Database Technical Manual: Update

28.1 million in life-cycle costs) that Tennessee may realize if it were to adopt the LEC design as its state energy code. These state-level estimates are further aggregated to the national level, estimating the potential total impact from nationwide adoption of the LEC design to be 34 441 GWh and

Building industry reporting and design for sustainability (BIRDS) commercial database technical manual: update

1.0 billion for one year’s worth of construction for a 10-year study period.

BIRDS v3.1 Tutorial for Low Energy Residential Database

............................................................................................................................ iii Preface ................................................................................................................................ v Acknowledgements ......................................................................................................... vii Author Information ........................................................................................................ vii List of Acronyms ............................................................................................................. xv

Reducing the impacts of weather variability on long-term building energy performance by adopting energy-efficient measures and systems: a case study

.............................................................................................................................................................. I PREFACE ............................................................................................................................................................... III ACKNOWLEDGEMENTS .......................................................................................................................................... V AUTHOR INFORMATION ........................................................................................................................................ V LIST OF ACRONYMS ............................................................................................................................................. XV

Life-cycle carbon and cost analysis of energy efficiency measures in new commercial buildings

.............................................................................................................................. i Preface ............................................................................................................................... iii Acknowledgements ........................................................................................................... v Author Information ......................................................................................................... vi List of Acronyms .............................................................................................................. ix

Beyond the code: Energy, carbon, and cost savings using conventional technologies

This case study uses whole-building simulation software to investigate the ability of alternative sets of energy conservation measures to limit the sensitivity in energy use and heating, ventilation, and air-conditioning (HVAC) peak electricity demands by residential buildings due to weather variability. Four alternative building designs are considered: a net-zero energy design based on the National Institute of Standards and Technology (NIST) net-zero energy residential test facility (NZERTF), a comparable, yet less efficient design built according to the 2015 International Energy Conservation Code (IECC), and two low-energy designs at varying levels of energy-efficiency. The findings from this study reveal which measures best ensure robust annual energy performance and occupant comfort by low- and net-zero energy homes given weather variability, as well as how much resulting energy performances vary across the sets of conservation measures considered in this work.