Dynamic thermal behavior and cooling transmission loads of insulated concrete walls under varying environmental conditions for humid subtropical climate

In this study, the effect of insulation thickness and its position on the dynamic thermal characteristics of concrete walls is examined numerically. Regarding the effect of the thermal insulation layer, nine different wall configurations are studied. The analysis is carried out for wall elements with a varying orientation corresponding to each cardinal point for the cooling period and more specifically for the climatic conditions of Thessaloniki, Greece, which climate is classified as Humid Subtropical according to Köppen Climate Classification System, which is the same of Porto Alegre, in Brasil. In addition, diurnal cooling transmission loads are calculated by considering different indoor design temperatures; for the aims of this investigation three typical indoor design temperatures are taken into account (increasing from 24 oC to 28 oC, in steps of 2 oC). Results underline the significance of insulation thickness and position to maintain a stable indoor environment with low temperature fluctuations (decreasing ratio of heat wave temperature amplitudes, decrement factor), as well as to shift adequately the occurred temperature peaks to the inner surface (time delay of heat wave propagation, time lag). It is also seen that north and south oriented walls provide minimum cooling loads compared to walls facing east and west. Furthermore, as the indoor design temperature increases the cooling transmission loads decrease. The thermal performance of insulated concrete walls is studied by using the thermal-network modelling method under steady periodic conditions