BIM-Based Automatic Outdoor Thermal Environment and Thermal Comfort Evaluation System Using EnergyPlus-Driven Deep Learning

Abstract

During the design phase of a building project, evaluation of outdoor thermal environment is very difficult and time consuming and is generally neglected as an intractable performance dimension. The task is burdensome due to the high computational cost and time-consuming process of simulating the many parameters of the outdoor thermal environment. However, the wide acceptance of Building Information Modeling (BIM) at the design stage coupled with advances in neural networks and high-powered computers offers a promise that the simulation of outdoor thermal comfort performance of an architectural design can be computed, allowing its incorporation into an iterative design process. This research has produced a tool for comprehensive outdoor thermal environment evaluation as an add-in to a popular BIM tool with the intention of aiding designers in incorporating outdoor thermal comfort as a design consideration.

The strategy of this research was to develop a system to automatically evaluate outdoor thermal environments and thermal comfort of a BIM model using simulation-based deep learning and the COMFA human energy budget model. This research accomplishes the following objectives: 1) development of a model to predict surface temperatures of landscape objects using EnergyPlus simulation-based deep learning, 2) development of a model to estimate values of short-wave radiation based on a BIM model using Autodesk Revit Dynamo, 3) development of a COMFA thermal budget neural networks model to evaluate outdoor thermal comfort, and 4) development of a design guidance model using Dynamo for designers to better understand the outcomes of the evaluation.

The results of the developed system, called OTCBIM, show that landscape surface temperatures and the COMFA thermal comfort evaluation can be visualized in a BIM environment with simple user inputs (i.e., analysis date and time, human clothing, and human activity). The system provides an automated process to retrieve all parameters of the outdoor thermal environment solely based on the BIM model, incorporating them into calculations. The system is shown to provide results similar to those provided by COMFA, but requiring significantly less time and effort.

The OTCBIM is expected to help designers improve their models and decisions based on the thermal comfort evaluation. The key potential impact is to assure that future designed environments may include more settings that are thermally comfortable, ultimately reducing energy use, reducing expenditures to temper climate, lessening anthropogenic drivers or climate change, and providing health benefits of walkable environments.