Parameters for Thermal Energy Systems Resilience

Abstract

To provide a building design that is robust, adaptable, and affordable, one must understand the aspects of the building’s geographic location that will impact equipment selections, operating hours, and maintenance needs. One must also consider the building’s “thermal resilience,” i.e., its ability to withstand a heating plant outage. Designing for resilience is of growing importance, especially for military and government installations that must maintain critical functions even during outages. Buildings with a fast rate of temperature degradation with the loss of heating system function have low resiliency; buildings with a slower rate of temperature degradation have higher resiliency. In extreme cold climates, resiliency can play an integral role in protecting property during an outage. A drop in indoor temperature can pose a risk of freezing plumbing, which can lead to burst pipes and interior flooding that can cause enormous and costly damage, and which can effect a loss of workspace in an office building. More resilient designs must consider not only building HVAC installations, but also building envelope and the whole energy infrastructure, including thermal capacity of concrete and brick walls, internal water pipes, critical system redundancy, outside insulation without weak points, and a centrally controlled, low carbon hot water heat supply. This paper describes a quantitative approach to evaluate a system’s resiliency based on analytical and experimental studies conducted under IEA EBC Annex 73 and the Environmental Security Technology Certification Program (ESTCP) project Technologies Integration to Achieve Resilient, Low-Energy Military Installations, to evaluate building energy performance in extreme climate conditions. This work recommends that more thermally resilient designs for buildings in cold climates include consideration of increased thermal resistance of the building envelope, improved whole-building airtightness, and higher thermal mass.