EnergyPlus as a forensic tool: Thermal reconstruction of a crime scene using calibrated simulation

This study utilized energy simulation in support of a forensic pathology time of death analysis for a corpse discovered in a single family residence two years prior to the study. In order to produce an accurate estimate of the interior temperature profile at the time of death, a thermal model was constructed using EnergyPlus and calibrated using environmental monitoring data from the site. The thermal model was able to predict the temperature in the room of interest within 1.4°C (2.5°F) with 90% confidence. This model was then altered to account for known differences between the monitoring period and the period of interest, and used to predict what the temperature profile had been at the time of death. This study adds to a small body of work that compares simulated to measured performance data for unconditioned spaces, which should have a growing relevance as building energy performance simulation (BEPS) tools are used to model passive strategies. 1. IN T R O DU C T I O N This project began with an unlikely telephone call from an attorney seeking expert advice for a homicide trial. Two years prior, a body had been discovered in the closet of a two-story home in the greater Sacramento area (Figure 1), and a suspect had been arrested. With the trial imminent, the question to us was, would we be able to determine the temperature in the closet in the specific building during the few days prior to the discovery of the deceased? Crime scene photographs showed that the discovered. The temperature of the environment was a critical component of the time of death analysis, the findings of which might help the jury determine the verdict. F igure 1. The two-story house in question. Because the findings would need to withstand courtroom scrutiny, the accuracy and defensibility of this study were critical. While we did not find a precedent for such a forensic study in the literature, there is a body of work that seeks to accurately predict thermal conditions in buildings for design and operation using building energy performance simulation (BEPS). In order to increase the accuracy of a BEPS model, studies have shown that a process of calibration can be used