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ABSTRACT
Retrofitting existing buildings shows promise for reducing energy consumption and greenhouse gas emissions. However, selecting the appropriate energy retrofit strategy (or strategies) requires careful planning, detailed information about a building's current condition and historical energy consumption patterns, and evaluation of multiple retrofit options. One retrofit strategy, using phase-change materials (PCMs) as a relatively straightforward means of increasing the thermal mass of an existing building, continues to be of interest to building owners, operators, and utilities alike. Despite the seeming ease of installation (e.g., PCMs can be layered on top of existing acoustical ceiling tiles rather than removing drywall to add insulation to exterior walls), a few primary factors need to be considered before applying PCMs in existing buildings. This paper presents a novel process for selecting PCMsfor building energy retrofits, comprising an evaluation of both the candidate building as well as the PCM. This process includes goal setting for the energy retrofit as well as the PCM installation, evaluation of an existing building to ensure that it is a good candidate for PCM integration, and, finally, analyzing the energy-savings potential of PCM integration as a retrofit strategy. This process was developed based on the results of five case studies conducted by the authors, including three experimental commercial building PCM installations as well as simulation results from two residential buildings. The authors present how the application of this process would have changed the choices made by stakeholders involved in the cases studied, thereby avoiding some of the less desirable results of those projects.
INTRODUCTION
Buildings account for more than one-third of the total energy use worldwide (Rabani et al. 2017). The buildings industry in the United States accounts for approximately 40% of the U.S.' primary energy consumption, and existing buildings are one of the main sources of carbon dioxide (CO2) emissions (EIA 2018). In 2016, space heating and cooling in buildings accounted for approximately 30% of the total CO2 emissions from commercial buildings and 38% of the CO2 emissions from residential buildings in the U.S. (Leung 2018). Therefore, retrofitting buildings, and reducing the space heating and cooling demand, in particular, is one effective means of supporting the reduction in energy demand and carbon emissions. Indeed, retrofitting buildings has been shown to be effective in...