Net-Zero Homes - It's About More than Energy: A Case Study of Power Performance
William M. Healy, Wenqi Guo
Numerous demonstrations of net-zero energy homes show that these houses are technically feasible, yet the approach to generating that annual energy balance could impact how the homes impact the utility grid or on-site storage applications. It is contended here that examination of power profiles of net-zero energy homes should play a key role in assessing energy performance and helping grid operators plan for a proliferation of such homes. A series of metrics are discussed that could help characterize power profiles that represent net-zero energy homes compared to conventional homes. A case study of these metrics is provided for a single-family net-zero demonstration facility. These metrics stress the overall peak power demand over the year (16.1 kW) and by season and identify the key contributors to those peak powers (dryer, heat pump, oven, heat pump water heater). The variability in the power has been described by a bumpiness metric as well as standard deviations. Defrost cycles from the heat pump as well as cloud cover on the photovoltaics are responsible for significant minute-to-minute variations in power. Rates of change of power along with the times of day when those power derivatives achieve their minimum and maximum values are compiled.
Proceedings of the 2018 ACEEE Summer Study on Energy Efficiency in Buildings
and Guo, W.
Net-Zero Homes - It's About More than Energy: A Case Study of Power Performance, Proceedings of the 2018 ACEEE Summer Study on Energy Efficiency in Buildings, Pacific Grove, CA, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=925683
(Accessed November 29, 2023)