Challenging issues in stochastic calibration based on bayesian paradigm for building energy model

Abstract

Bayesian calibration has been used to transform the prior distributions of unknown inputs inherited in a building energy simulation model into the trustworthy posterior distributions. It obtains the posterior distributions using a joint distribution composed of a likelihood function and prior distributions of unknown inputs in the Bayesian paradigm. In other words, it provides higher benefits in terms of a stochastic approach than the deterministic calibration and the feasibility of their calibrated results was sufficiently discussed. However, challenging issues in Bayesian calibration still remains as follows: (1) inappropriate selection of prior distributions, (2) truncated sample dataset of the likelihood functions. The aforementioned issues can increase the risks of Bayesian calibration. This paper aims to inform the risks of Bayesian calibration associated with the aforementioned issues through a reference case study. For this study, the Gaussian Process (GP) emulator, which can be regarded as a meta-model of Building Performance Simulation (BPS) tools, was used to reduce the simulation run-time. Bayesian calibration using the GP emulator was implemented with what-if scenarios considering the aforementioned issues. And then the validated models were used for a stochastic retrofit analysis of glazing systems. With the results of the estimated posterior distributions, validation, and stochastic retrofit, this paper presents Bayesian calibration issues regarding the selection of prior distributions and sample dataset of the likelihood functions.