Demonstration of a modeling toolkit for the design of building electrical distribution systems
Anay Waghale, Shat Pratoomratana, Michael E. Poplawski · 2022
The deployment of building equipment (e.g., lighting, security) and miscellaneous electrical loads that fundamentally require DC power for operation is increasing. Powering these DC loads has traditionally required an AC/DC converter, but the installation of photovoltaic (PV) and battery energy storage systems (BESS) that primarily produce DC power eliminates the need for AC/DC converters at each end-device. However, analyzing system energy efficiency and cost for different electrical distribution architectures can be challenging as software tools that support this are not readily available. This paper presents preliminary results from the demonstration of the Building Electrical Efficiency Analysis Model (BEEAM) toolkit that was developed to address this gap. Three 8-luminaire lighting systems comprised of market-available products were designed and modeled: one that used traditional AC distribution, a second that used a hybrid AC-to-centralized-DC electrical distribution architecture, and a third that used a hybrid AC-to-distributed-DC architecture. Notably, AC/DC conversions are required in all three systems. BEEAM models for LED drivers and Power-over-Ethernet (PoE) switches were created using laboratory characterization data. The lighting systems were simulated in a Modelica based simulation environment, and the results were compared with each other and physics-based expectations. Simulation results show that PoE system efficiency is highly dependent on both device specification (e.g., LED driver and PoE switch efficiency) and system architecture (e.g., PoE switch loading) choices, as expected. For the products and system architectures selected for this study, the two DC systems were found to be less efficient than the AC system over the course of typical operation. In future work, simulation results will be compared with laboratory measurements to verify the accuracy of results produced with the toolkit, and the toolkit will be used to support the deployment of a real-world system to validate toolkit usefulness for design, and lighting systems with integrated PV and BESS will be simulated to quantify the energy performance improvements that result from the elimination of some AC/DC converters.