Heat Mapping Drones: An Autonomous Computer-Vision-Based Procedure for Building Envelope Inspection Using Unmanned Aerial Systems (UAS)

摘要

The building sector accounts for about 76% of electricity use and 40% of primary energy use and associated greenhouse gas (GHG) emissions in the United States (US DOE 2015). Research conducted in metropolitan Boston, Massachusetts, found that in 135 residential houses surveyed with infrared (IR) technology, heat transfer and air leaks through cracks were the reason behind about 40% of energy loss (Shao 2011). More than half of all US commercial buildings in operation today were built before 1970 and this large existing building stock performs with general lower efficiency (US DOE 2015). Heating, ventilation, and air conditioning (HVAC) and lighting loads in existing residential and commercial buildings consume 35% and 11% of total building energy, respectively, which totals more than 17 quads of residential and commercial building's primary energy use (US DOE 2015). In order to achieve substantial energy savings in existing and deteriorating built environments, retrofitting strategies that respond to accurate and reliable energy audits should be implemented. To identify compromises in the building envelope, energy auditors traditionally use tools such as blower door tests to detect infiltration/exfiltration regions and thermal bridges (US DOE 2012). Unfortunately, predicted savings and delivered savings typically do not match. This can be attributed to imprecise energy audits, which may lead to lower than expected energy savings, no energy savings, or in some cases occasional increase in energy use. Myriad negative effects follow, including unaccounted for environmental impacts, discrediting energy efficiency retrofits and causing a loss of investment funds. This is typically a result of many challenges that energy auditors face, including insufficient building information that leads to misrepresentation in energy models, overestimated savings, ineffective selection of improvement strategies, and incomprehensive improvement scopes that result in missed opportunities (Shapiro 2011). In large commercial buildings energy auditors typically emphasize exciting technical challenges that focus on HVAC systems or the integration of renewable energy in the form of solar panels while ignoring less attractive building envelope issues such as window performance, thermal bridges, air sealing, and insulation deterioration. This can also be coupled with situations that are considered uneasy, dangerous, or inaccessible to the auditor, including high-rise or large-span structure envelope inspections as well as building roofs (Shapiro 2009). In this paper, a methodology is presented to address these critical challenges by employing an Unmanned Aerial Systems (UAS) platform.