Quantity and electricity consumption of plug load equipment on a university campus

Moira Hafer

doi:10.1007/s12053-016-9503-2

Abstract

The percent of energy consumed by plug load equipment in commercial buildings is on the rise. Research conducted in the past has included surveying plug load equipment, measuring plug load electricity consumption and equipment operating patterns, and studying plug load reduction solutions in office buildings, but plug load energy use across other building types is poorly understood. A university campus, which houses many building types, presents a unique opportunity to understand plug load profiles across building types. In this study, an equipment inventory was performed in 220 buildings on Stanford University’s campus, totaling 8,901,911 ft2 of building space and encompassing lab buildings, office buildings, recreation facilities, public space, and service buildings. Within these buildings, 110,529 pieces of plug load equipment were recorded. Energy consumption estimates were developed from published values and used to evaluate the aggregate plug load energy consumption of this equipment by equipment type and by building type. In total, it is estimated that the plug loads from these buildings consume nearly 50 million kWh per year and comprise 32% of the electricity consumption of the buildings surveyed. This data can be used to better target energy conservation efforts throughout multiple sectors.

Highlights

Equipment with non-traditional end uses in commercial buildings in the USA consumed over 7 billion MMBtu in 2012, and the energy intensity of these miscellaneous loads is expected to increase by 21.4% by 2040 (Energy Information Administration 2014)
Results are presented by type of building in order to highlight underlying trends within and across building types to demonstrate the relevance of this inventory to various sectors
The plug loads collected and analyzed in this study were estimated to comprise 32% of the total energy consumption of the 220 buildings included in the inventory, with lab equipment consuming the highest portion of electricity and computers and monitors as the most prevalent types of equipment on campus

Summary

Introduction

Equipment with non-traditional end uses in commercial buildings in the USA consumed over 7 billion MMBtu in 2012, and the energy intensity of these miscellaneous loads is expected to increase by 21.4% by 2040 (Energy Information Administration 2014) One reason for this projected increase is that current building energy efficiency standards do not cover the majority of this miscellaneous equipment, as they do for equipment with traditional end uses such as lighting and space conditioning. As these traditional end uses become more efficient, the amount of energy that goes towards them decreases as a percent of total building energy consumption, creating a simultaneous rise in the percentage of electricity that is used by other miscellaneous equipment, hereafter deemed Bplug loads^ in this paper. A combination of savings strategies like this demonstrated a 47% reduction in associated electricity consumption in one office building (Lobato et al 2011)

Objectives

Methods

Results

Conclusion