Time Domain Analysis of the Temperatures in an Electrical Auxiliary Building Room

A computational fluid dynamics (CFD) model has been developed to predict air temperatures within the switchgear room environment of a nuclear plant’s Electronics Auxiliary Building (EAB). In order to validate the CFD model output, a scale model experiment has been developed using an analytical model to properly scale important EAB room parameters to allow small scale experiments to be performed for validation of the CFD model. The focus of this paper is the development of the methodology used to accurately predict the bulk air temperature or the EAB room. The CFD model is compared to a simple lumped parameter model as well as a scale model experiment. The scaling approach matches the eigenvalues of the lumped parameter model. An experiment based on this scaling approach was performed and compared with CFD output. The time predicted by the CFD model of the Electrical Auxiliary Building room for the average air temperature to increase from 17.7 °C (64 °F) to 40 °C (104 °F) is 23.5 minutes. The lumped parameter analytic solution produces a mean time of 22 minutes. The heat up time for the experiment matches the CFD model providing confidence in the fidelity of the CFD model.