Case Study: Plug Load Strategies for Zero Energy Buildings

Plug Load Strategies for Zero Energy Buildings:
A case study on the zero energy historical renovation of the Wayne N. Aspinall Federal Building and U.S. Courthouse

Decision Guides for Plug and Process Load Controls

PPLs account for an increasingly large percentage of commercial building energy use. The primary energy use associated with PPLs is projected to grow from 30% to 35% of total commercial building energy use between 2010 and 2025 because the number and energy intensity of plug-in devices continue to increase. This is due to the wide range of U.S. commercial building types, uses, sizes, and vintages, PPL energy consumption can range from 10% in warehouses to nearly 60% in food sales.

Plug and process load management resources

DOE’s Better Buildings Alliance has resources for controlling plug and
process loads in commercial buildings, and the strategies on their website can be applied to schools.

Advanced Energy Design Guide for K-12 School Buildings: Achieving Zero Energy

This guide provides user-friendly guidance for achieving a net zero energy K-12 school building. It includes a set of energy performance targets for all climate zones. Strategies on how to achieve these energy targets are provided throughout the guide and include setting measurable goals, hiring design teams committed to that goal, using energy simulation throughout the design and construction process, and being aware of how process decisions affect energy usage.

Plug Load Strategies for Zero Energy Buildings (Wayne N. Aspinall Federal Building and U.S. Courthouse)

Case study about how the U.S. General Services Administration successfully renovated the historic Wayne N. Aspinall Federal Building and U.S. Courthouse. GSA’s goals were to preserve the building’s historic features, and achieve Zero Energy Building status. This case study provides an overview of how reducing plug load energy helped achieve the Zero Energy Building status.

Better Buildings Alliance, Plug and Process Loads in Commercial Buildings: Capacity and Power Requirement Analysis

This brochure addresses gaps in actionable knowledge that can help reduce the plug load capacities designed into buildings. Prospective building occupants and real estate brokers lack accurate references for plug and process load (PPL) capacity requirements, so they often request 5–10 W/ft2 in their lease agreements. This brochure should be used to make these decisions so systems can operate more energy efficiently; upfront capital costs will also decrease. This information can also be used to drive changes in negotiations about PPL energy demands.

An Analysis of Plug Load Capacities and Power Requirements in Commercial Buildings: Preprint

Plug and process load power requirements are frequently overestimated because designers often use estimates based on “nameplate” data, or design assumptions are high because information is not available. This generally results in oversized heating, ventilation, and air-conditioning systems; increased initial construction costs; and increased energy use caused by inefficiencies at low, part-load operation. Rightsizing of chillers in two buildings reduced whole-building energy use by 3%–4%. If an integrated design approach could enable 3% whole-building energy savings in all U.S.

Selecting a Control Strategy for Plug and Process Loads

Miscellaneous electrical loads (MELs) are building loads that are not related to general lighting, heating, ventilation, cooling, and water heating, and typically do not provide comfort to the building occupants. MELs in commercial buildings account for almost 5% of U.S. primary energy consumption. On an individual building level, they account for approximately 25% of the total electrical load in a minimally code-compliant commercial building, and can exceed 50% in an ultra-high efficiency building such as the National Renewable Energy Laboratory's (NREL) Research Support Facility (RSF).