Experimental validation of a dynamic numeric model to simulate the thermal behavior of a facade

The process of analysis and design of energy saving measures aimed to reduce building energy consumption, both in the design of new constructions and in the refurbishment of existing ones, has led to the need to solve increasingly complex problems with the consequent demand to develop complex models and new calculation tools, which often entails the coupling of different models each one of them to solve a specific task and always under the requirement of obtaining accurate and reliable results. This article presents a modular dynamic model based on a finite difference scheme with matching conditions between wall layers to record the different thermophysical properties of layer materials and accurately compute the heat flux through the building envelope. The aim of this model is to simulate the energy behavior of building envelopes and to allow the connection, via a co-simulation procedure, with other codes based in models for addressing complex issues usually not included in standard Building Energy Simulation (BES) tools. For that, the simulation model was designed with a modular structure in order to facilitate its connection, when required, to other codes written in C++. The thermal model has been validated experimentally, using data from two full-scale outdoor test cells with different façade constructive solutions for different ventilation and blind opening regimes. An additional code-to-code comparison was also performed between the developed model and the Energy-Plus software to complement the results of the experimental validation. The results obtained in the validation process show the ability of the proposed numerical model to simulate the energy performance of the envelope and of the test cell globally in a wide variety of situations, predicting internal air temperature and envelope internal surfaces temperatures which meet the requirements usually established for the validation of building energy simulation tools. The numerical formulation of the introduced model and its characteristics that combine flexibility, modularity and accuracy for the calculation of the thermal behavior of a façade and is able of an easy connection to external codes written in C++ to solve more complex problems, allow to consider the present work as innovative and novelty on the literature. •Innovative modeling for energy performance prediction of building envelopes.•The method has a modular design that facilitates co-simulation.•Experimental validation and inter-mode