Heat and moisture exchanges between building envelope and its interior ambience are related and continued. The current state of art of the hygrothermal interactions modeling between envelope and ambience of building calls upon to dynamic simulation tools where the coupling of heat and mass transfers are generally not considered.In this work, a hygrothermal transfer model in multilayer walls (HAM) is dynamically coupled to a thermal building model (BES). The Coupling concerns the implementation of a co-simulation between COMSOL Multiphysics©, a simulation tool in finite element for hygrothermique transfer through the envelope, and TRNSYS, a thermal simulation tool for building and dynamical systems. The HAM-BES coupling efficiency was verified by carrying out an experimental validation performed in the framework of Annex 41 of the International Energy Agency. Subsequently, a case study is conducted in order to evaluate the effect of taking into account the 1D and 2D hygrothermal transfer modeling in the envelope on the global thermal and hydric behaviors of the building. Results confirm the direct impact of modeling the coupled heat, air and moisture transfer through the envelope on the overall hygrothermal behavior of buildings

Green walls and green roofs are innovative construction technologies involving the use environmentally friendly materials. In addition to their aesthetical and environmental benefits, green walls have significant thermal effects on buildings and heat islands within high-density urban areas. In this paper, we study the impact of an innovative green wall system on building energy performance. These green walls have specific composition and particular geometry that can lead to higher thermal performances and therefore more significant impact on building energy performance. The development, validation and prior integration of a hygrothermal green wall model in a transient building simulation tool make possible the assessment of the energy performance of buildings when covered by green walls. The used model was adapted to be the particular forms and composition of the studied green walls. In parallel, this type of green walls has been installed on a one tenth building mockup to be experimented. The aim of the experiment is to measure the thermal effects and to calibrate some parameters of the numerical model. The results highlight the thermal benefits of this kind of green walls in summer condition. They reduce annual energy demand of building up to 37% for hot climates.

Several rural regions located in Africa are experiencing recurrent and even permanent problems in terms of energy production, supply, and distribution to citizens. This study was conducted to investigate the relevance of the use of a new solar technology that is gradually responding in Europe and in industrialized countries. It is about the use of hybrid photovoltaic thermal (PV/T) solar panels that co-produce electricity and hot water for local use. Furthermore, in Africa, local use of solar energy can provide a share in the energy mix. This work is motivated by the lack of studies on these hybrid solar panels in tropical climates. Hence, the paper examines the potential for integration of these systems in small households. A complete PV/T system consisting of solar panels, pump, storage tank, batteries, and controllers was tested and calibrated by using the TRNSYS simulation tool. A comparative study could thus be carried out for the performance of PV/T in a tropical climate (case of the city of Koua in the Comoros) to its performance in Mediterranean and continental climates (Marseille in the south and Longwy in the northeast of France). The results quantify the performance of the PV/T in the three climates and show that the performance in the town of Koua is 44% to 54% higher than in European climates. It can be concluded from this study that the Comorian market and more generally the sub-Saharan market for PVT systems has a good potential for development.