Comprehensive analysis of the influence of different building modelling approaches on the results and computational time using a cross-compared model as a reference

Abstract

A large number of Building Energy Simulation (BES) tools with a different focus and degree of detail are available however, increasing the model complexity usually increases the modelling time and the number of required inputs, not always leading to better accuracy. Therefore it is important to find the trade-off between model complexity and computational time having in mind the purpose and goal of the simulation study and the available inputs. To shed some light on these aspects, different modelling approaches (i.e. thermal zone model, window model, thermal mass, etc…) are implemented using a cross-validated Simulink model of an office cell and the influence of each analysed aspect on the hourly results is addressed using the Goodness-of-fit and the computational time. As a result, it is observed that modelling the thermal zone with a two-star model leads to a good agreement with the surface-to-surface detailed radiation model in terms of energy balance and operative temperature in the centre of the room, but deviations are present when the temperature in a specific location of the room (e.g. near the window) has to be evaluated. In addition, it is found that a simplified thermal zone model such as one-star model allows important savings in terms of computational time, but leads to deviations in the dynamic behaviour. However, the energy balance can have an acceptable accuracy for specific applications when the inputs are calibrated. Regarding the window model, the results show that it strongly affects the accuracy of the simulation. Furthermore, many aspects that are often overlooked, such as the models of the adiabatic structure, sky model, capacity of the air node, distribution of the radiative gains to the surfaces of the enclosure and convective and radiative exchange coefficients, influence both the accuracy of the results and the computational time.