Modeling thermal and wind processes in the near-wall layer of building envelopes subjected to insolation

Introduction. Insolation patterns play a decisive role in creating a comfortable microclimatic environment in building spaces. This is a relevant problem of thermal safety assurance for modern construction projects and better sanitary and hygienic conditions of indoor environments. The radiant energy of the sun is a priority in the architectural and structural design and the design of thermal shells of buildings. Materials and methods. Theoretical, full-scale microclimatic and thermophysical field studies on structural envelopes of buildings were conducted to identify the contribution of insolation to thermal and wind patterns in the near-wall layer of building envelopes. These methods were verified using the analysis of research techniques, developed by domestic and foreign authors specializing in thermal physics of energy-efficient buildings. The authors developed a set of methods allowing to conduct new experimental studies of physical processes in the thermal air shell of the near-wall layer of envelope structures of real buildings. Results. As a result of the field studies of thermal and wind processes underway near the structural envelope of buildings subjected to prolonged insolation, the authors learned that the microclimate turns uncongenial in the near-wall air layer of buildings and in building spaces. This microclimate has unique thermal conditions. The extent of impact, made by the external walls of buildings on the generation and regulation of thermal and wind patterns of the near-wall microclimate was identified. A model of convective flows of the near-wall microclimatic layer of multi-storied residential buildings was developed. These convective flows demonstrate high capacity and vertical mobility and cause the air mass to travel through the space of a building floor that has columns due to the thermal contrast between the opposite walls of buildings. Conclusions. The authors have identified the contribution of solar energy to thermal and wind conditions in the air layer of thermal protective shells of buildings subjected to insolation. The mechanism, underlying the thermophysical processes arising in the course of interaction between insolation and the active surface of the thermal protective shell, is identified. The authors have formulated the preconditions for adjusting the design air temperature when assessing the thermal stability of building envelopes, taking into account the insolation conditions of facade systems of buildings. The preconditions for the relationship between outdoor and indoor air environments, as well as methods of natural aeration of premises have been demonstrated.