Remodeling of RC Circuit Building Thermodynamics Model with Solar Radiation Based on A Regularization-like Technique

In this paper, we present a remodeling scheme of so-called RC (Resistance-Capacitance) circuit building thermodynamics models with solar radiation. We first build a 3-D building structure model of a real building in Tokyo Institute of Technology, a detailed EnergyPlus simulator associated with the structure model, and its RC circuit model identified by BRCM (Building Resistance-Capacitance Modeling) MATLAB toolbox. It is then confirmed that the RC circuit model does not always fit the temperature trajectories by EnergyPlus in the presence of solar radiation, while it works well in the absence of radiation. This paper is thus intended to reidentify the solar absorption coefficients, which quantifies the effects of solar radiation on zone temperatures, through data generated by EnergyPlus. We first apply the standard least square method and point out two difficulties: (i) the rank of the data matrix gets ill-conditioned, and (ii) increasing the volume of the data is prohibited due to high dimensionality of the RC circuit model. We thus employ a regularization technique without increasing the computational efforts and validate the resulting model through comparisons with the EnergyPlus data.