Computer Modeling of Heat Flow in Floor Structures on the Ground of Logistics Infrastructure Buildings

The purpose of this work is to develop a computer model of heat flow in a floor on the ground, taking into account the radiogenic heat flux of the Earth, in order to assess the energy efficiency of building structures. The object of modeling is a rectangular concrete floor slab placed on the ground, with possible perimeter insulation by a strip of thermal insulation. The model considers the thermal conductivity of materials, the temperature of indoor air and soil, as well as a steady-state two-dimensional heat transfer process. Existing approaches to floor-on-ground insulation were analyzed in accordance with Ukrainian and European standards, and principles of numerical modeling using the finite difference method and iterative solution for the heat conduction equation with variable coefficients were proposed. The stated goal is achieved by solving the problem of temperature field simulation in the slab, insulation, and soil, taking into account boundary conditions, building geometry, and the thermal characteristics of materials, which makes it possible to evaluate transmission heat losses for different insulation widths. For convenient practical application, additional parameters should be introduced to account for different soil types, insulation thicknesses, and economic feasibility, while ensuring compliance with energy efficiency requirements for logistics infrastructure buildings. The most important results include the development of a 2D heat transfer model that confirms the concentration of heat losses in the edge zones of the floor and demonstrates a reduction of 20–25% in losses with 2–3 m wide perimeter insulation. The model also shows consistency with engineering methods according to DSTU EN ISO 13370:2022 and DSTU 9190:2022. The significance of the obtained results lies in the fact that the proposed methodology allows not only to optimize insulation for buildings with large ground-floor areas, improving energy efficiency and reducing energy consumption, but also to serve as a basis for updating regulatory standards, particularly during the renovation of existing facilities