Design Optimization Workflow for a Dynamic Mass Envelope System using Complementary Digital and Physical Testing Methods

ABSTRACT: Building envelopes significantly contribute to energetic gains and losses, relying on insulation and HVAC systems to maintain thermal comfort. The Thermally Active Ceramic Envelope (TACE) is being developed to capture, transform, re-distribute bioclimatic energy flows rather than act as a barrier. By redirecting rather than rejecting thermal energy, building envelopes act as on-demand variable mass systems which can achieve the same balancing effects as traditional thermal mass approaches, without such intensive material requirements. By managing entropy production at the envelope, it is reasonable to expect lower mechanical system energy expenditures to maintain thermal comfort. This paper outlines two parallel methods of analysis, physical and digital, used to inform design decisions in the development of TACE systems. In the first method, digital simulation, multiple digital models were prepared to characterize the thermal performance of TACE tile modules. With a well-prepared simulation model, design iterations can be quickly tested for efficacy. The digital simulation model was developed using conservation of mass and energy equations and validated against CFD testing to assess possible performance of the TACE system. The second method of analysis is physical thermal characterization testing of TACE tile assemblies, using a modified hot-box test chamber to provide accurate thermal results. To leverage the benefits and minimize the shortcomings of each of the two methods, experimental results from this physical testing are used as a calibration tool for the digital simulation models. Calibration inputs from the physical testing were used to adjust the digital simulation models to correlate all analysis results. With a calibrated digital simulation framework, TACE tile modules can be proposed and tested before investing time and materials into developing further prototypes. The end result is a design workflow to evaluate and assess thermal performance of TACE tile modules.   KEYWORDS: Active Facade, Thermal Transfer, CFD, Energy Modeling, High-Performance Facade