Linking Microclimate and Energy Use with a Low Cost Wall Mounted Measurement System

Urban microclimate plays a critical role in overall urban energy demand and efficiency. At building scale, the energy use and internal conditions are directly impacted by local microclimate. The direct link between building energy use and local microclimate is through building envelope heat fluxes. The Building Temperature Energy Monitoring System (B-TEMS) project was created as a low cost solution to investigate these heat fluxes through the walls of commercial buildings. This paper describes the design and assembly of Arduino microcontroller-based temperature and humidity sensors called B-TEMS, which record ambient air temperature, wall surface temperature, and relative humidity for both internal and external environments. These systems are used to quantify energy losses through two walls in a building at the University of Utah. The B-TEMS are deployed by attaching them to the inside and outside of exterior walls and windows. Ambient air temperature and humidity were measured via a Sensirion SHT sensor while wall surface temperature was measured by a Melexis MLX infrared temperature sensor. Data were collected on an SD card every 30 seconds using an Arduino Pro Mini for several hours. Results from the experimental analysis are used to compare results for predicted temperatures using the methods in Energy Plus, a commonly used open-source building energy modeling software. Measured differences between local experimental results and modeled results from EnergyPlus will help researchers evaluate the effects of including microclimate data on model accuracy. This system provides a low cost, simple solution to monitor microclimate and wall fluxes together, leading toward more accurate building energy simulations.