A Comparison of Commercial Building Retrofits Using EnergyPlus for Energy and Emissions Savings

Abstract

For existing commercial buildings, structural retrofits and energy efficiency actions play an important role in providing potential energy and cost saving options to the building owner or operator. Depending on the type of modification made to the building or its operations, the environmental impacts associated with the building may also be reduced. The aim of this research is to compare three simple energy efficiency changes for a modeled commercial office building and quantify their relative impacts in terms of greenhouse gas emissions. Both direct emissions from on-site combustion and indirect emissions through electricity purchases are compared. Hourly emission factors for electricity purchases are used for calculations of CO2 emissions. These emissions factors are unique to the electrical grid in the region where electricity is purchased, and they vary both diurnally and seasonally. In this paper, the selected energy-saving retrofits and energy efficiency actions are: adjusting lighting intensity, adding insulation, and changing the allowable range of temperatures in the buildings HVAC control scheme. Large and small office building prototype models are simulated using the U.S. Department of Energy’s open source building energy modeling software, EnergyPlus. Finally, the relative environmental impacts based on the type of energy modification and the size of the office building is presented in terms of CO2 emissions.