A Modeling Toolkit for Comparing AC and DC Electrical Distribution Efficiency in Buildings

Avpreet Othee; James Cale; Arthur Santos; Stephen Frank; Daniel Zimmerle; Omkar Ghatpande; Gerald Duggan; Daniel Gerber

doi:10.3390/en16073001

Energies (Mar 2023)

A Modeling Toolkit for Comparing AC and DC Electrical Distribution Efficiency in Buildings

Avpreet Othee,
James Cale,
Arthur Santos,
Stephen Frank,
Daniel Zimmerle,
Omkar Ghatpande,
Gerald Duggan,
Daniel Gerber

Affiliations

Avpreet Othee: Department of Systems Engineering, Colorado State University, Fort Collins, CO 80523, USA
James Cale: Department of Systems Engineering, Colorado State University, Fort Collins, CO 80523, USA
Arthur Santos: Department of Systems Engineering, Colorado State University, Fort Collins, CO 80523, USA
Stephen Frank: National Renewable Energy Laboratory, Golden, CO 80401, USA
Daniel Zimmerle: Department of Systems Engineering, Colorado State University, Fort Collins, CO 80523, USA
Omkar Ghatpande: National Renewable Energy Laboratory, Golden, CO 80401, USA
Gerald Duggan: Department of Systems Engineering, Colorado State University, Fort Collins, CO 80523, USA
Daniel Gerber: Lawrence Berkeley National Laboratory, Berkeley, CA 94550, USA

DOI: https://doi.org/10.3390/en16073001
Journal volume & issue: Vol. 16, no. 7
p. 3001

Abstract

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Recently, there has been considerable research interest in the potential for DC distribution systems in buildings instead of the traditional AC distribution systems. Due to the need for performing power conversions between DC and AC electricity, DC distribution may provide electrical efficiency advantages in some systems. To support comparative evaluations of AC-only, DC-only, and hybrid AC/DC distribution systems in buildings, a new modeling toolkit called the Building Electrical Efficiency Analysis Model (BEEAM) was developed and is described in this paper. To account for harmonics in currents or voltages arising from nonlinear devices, the toolkit implements harmonic power flow, along with nonlinear device behavioral descriptions derived from empirical measurements. This paper describes the framework, network equations, device representations, and an implementation of the toolkit in an open source software package, including a component library and graphical interface for creating circuits. Simulations of electrical behavior and device and system efficiencies using the toolkit are compared with experimental measurements of a small office environment in a variety of operating and load configurations. A detailed analysis of uncertainty estimation is also provided. Key findings were that a comparison of predicted versus measured efficiencies and power losses in the validation testbed using the initial toolkit implementation predicted device- and system-level efficiencies with reasonably good accuracy under both balanced and unbalanced AC scenarios. An uncertainty analysis also revealed that the maximum estimated error for system efficiency across all scenarios was 3%, and measured and modeled system efficiency agreed within the experimental uncertainty in approximately half of the scenarios. Based on the correspondence between simulation and measurement, the toolkit is proposed by the authors as a potentially useful tool for comparing efficiency in AC, DC, and hybrid AC/DC distribution systems in buildings.

Published in Energies

ISSN: 1996-1073 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Technology
Website: http://www.mdpi.com/journal/energies

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