Numerical data on heat flux of a novel controlled-temperature double skin façade

Hourly heat flux for variant boundary conditions of a novel controlled-temperature double skin façade (DSF) building element in a two- dimensional time- dependent study was determined. The building element is subjected to boundary conditions, characterizing different orientations (azimuth 0°, 90°, 180°, 270°) and climatic conditions of the four seasons. This data article provides detailed numerical data on the hourly heat flux, temperatures attained at the exterior and within the building element for six different geometries and for the variant boundary conditions under study. The external boundary conditions were determined with the use of the PVGIS tool, corrected in accordance to the sol-air temperature equation. The numerical simulation studies were performed with the use of the computational fluid dynamics (CFD) tool Comsol Multiphysics [2].


Specifications
Energy Analysed and processed output data Parameters for data collection The geometric parameters, which have been used as input for the development of the numerical simulation models, were obtained using experimental building elements. The international standard EN 10456: 2007 has provided the building materials' thermophysical properties [3] , while for those materials not included in the standard, their properties were obtained from laboratory tests. The temperature profiles, which were imposed on the exterior surfaces of the masonry to represent the variant climatic conditions under investigation, were obtained with the use of PVGIS [1] . Accordingly, data from the PVGIS tool [1] was obtained to be representative of the different orientations and seasons Description of data collection The values used for the development of the geometric models of the DSF building elements were based on actual experimental building elements. For the materials, whose thermophysical properties were acquired experimentally, their properties were measured based on the analysis of the temperature response of each material to heat flow impulses with the use of a measuring instrument for direct measurement of heat transfer properties. The PVGIS tool [1] was employed for the acquirement of climatic data, which was used as input for the definition of the external boundary conditions of the simulation models. The climatic data extracted was for the calendar months January (winter), April (spring), July (summer), and October (autumn) and for the orientations azimuth 0 °, 90 °, 180 °and 270 °. The acquired data were corrected using the sol-air temperature equation.

Value of the Data
• The data provided in this work presents the variability of heat flux for a building wall incorporating a DSF under variant external boundary conditions. • The data can be useful for both new and existing buildings, where the application of a DSF aims to the reduction of heat losses through the building wall and the improvement of the building's thermal performance. • The dataset can support researchers by demonstrating the methodology for the development of novel building elements and the definition the optimal design for application, given the key objective is improving the overall energy performance of the built environment.        Figures B1 -B24. For each of the investigated designs, Point 1 is located at the external surface of the building element; Point 2 is located within the thermal board and Point 3 is located within the glass mineral wool (points' location indicated in Reference  Figures 7-12).

Data Description
The summary of the cumulative daily heat flux are provided in Table 1

Experimental Design, Materials and Methods
The calculation procedure, based on two-dimensional time-dependent finite element numerical modeling which solves the equation of heat transfer for a novel DSF building element (AENAOS), has been performed by the followed steps:  Figure 1 , take into consideration existing construction solutions and restrictions related to the practical application of the building element. 3. Definition of the materials' thermophysical properties retrieved from the international standard EN 10456:2007 and laboratory tests [3] ( Table 2 ). 4. Generation of ambient temperature and solar radiation data with the use of the PVGIS tool [1] . In order to define the typical day for which the simulations are to be performed, the data of each month was statistically processed to determine the day whose mean statistical deviation was the smallest in relation to the mean values of the month, based on the following equation (standard deviation) [4] : . Definition of boundary conditions,of which the exterior boundary conditions were calculated using the sol-air temperature equation [5] : The temperature values used as exterior boundary conditions are presented in Table 3

Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships which have, or could be perceived to have, influenced the work reported in this article.