STOGO PARAPETO ILGINIO ŠILUMINIO TILTELIO EFEKTYVUMO TYRIMAS A++ KLASĖS PRAMONINIUOSE PASTATUOSE

Study on Linear Thermal Bridge Efficiency of Roof Parapet in A++ class industrial buildings

Abstract

The aim of the work is to determine the most effective option for the roof parapet installation in A ++ class industrial buildings and to determine the most rational option for installing a roof parapet. 

The objects of the study are as follows: the selection of the most effective material for the parapet support structure; the determination of the values and heat losses of parapet linear thermal bridges; the selection of the rational parapet insulation; the calculation of the simple payback time of the investment.

Research methods: analysis of technical and scientific literature, thermodynamic modeling, simulation.

In this article, the authors carried out a research on a typical linear thermal bridge of roof parapet of class A++ industrial building, based on the principles of energy and economic efficiency.

As of 1 January 2021, all heated newly constructed industrial buildings shall be not less than of an A ++ energy performance class buildings. This requirement is enshrined in the European Union Directive (Quinten et al., 2016) and in the Technical Building Regulation of the Republic of Lithuania ‘Design and Certification of Energy Performance of Buildings’ (STR 2.01.02:2016). In order to effectively design low-energy industrial buildings, it is recommended to calculate linear thermal bridges.

This study will further investigate a typical roof parapet unit of an A ++ class industrial building, modifying only the insulation thicknesses and the type of supporting frame. After performing the thermodynamic simulation the roof-wall junction thermal bridges are calculated and the most effective insulation option and simple payback time for the investment is identified.

Overall conclusions: Following the economic assessment, it was found that the cost of insulated wooden frame construction materials compared to the construction of silicate blocks is 16,5 percent higher, however, lower heat losses occur through such a unit. The calculated values of linear thermal bridges of roof parapets are better (i.e. less than 0,05 W/(mK)) only if the structure of the parapet is a wooden frame with mineral wool filling or when the parapet is made of the masonry of silicate blocks, insulated with mineral wool panels of at least 130 mm on all sides. Having conducted the applied research, is was found that it is most effective way to insulate the roof parapet of an A++ class industrial building is with 20 mm thick mineral wool panels and for the parapet construction to use a wooden frame with mineral wool filling. In this position, the value of the thermal bridge is equal to -0,0177 W/(mK). Taking into account the losses of the thermal bridge and the the simple payback time of the material, it is was found that V4 is most rational option. The simple payback time of this option is 2,2 years. The worst option is to design the roof parapet using silicate block construction and insulating it with 150 mm mineral wool panels (V9 version). The payback period for this option is 20,2 years.