Phase change materials (PCMs) show a good capability in absorbing massive heat when undergoing phase change, which have great potential to be incorporated into building envelopes to enhance indoor thermal comfort by preventing heat penetration into buildings and reducing energy requirements. In this work, a deep analysis of PCM enhanced-walls model has been conducted in six representative climate regions of Morocco: El Jadida, Fez, Marrakesh, Ifrane, and Errachidia. More in detail, numerical simulations were carried out to assess the thermal behavior and energy performance of a residential building integrated with four different PCMs. The results showed that the effectiveness and selection of PCMs strongly depend on local weather where they are applied, characteristics of HVAC systems, PCM layer thickness, and position. Furthermore, with reference to each climate zone, the appropriate PCM leading to the lowest annual energy consumption was identified. The findings show that PCMs are particularly suitable for Mediterranean climates, which a promising annual energy saving of about 41% was obtained. While, the lowest value was recorded in Errachidia city reveals that the integration of PCM has little effect in desert climate zone. As for the other climates considered, values of about 28% to 31% were achieved in the studied house model.

Hygrothermal models are important tools for assessing the risk of moisture-related decay mechanisms which can compromise structural integrity, loss of architectural features and material. There are several sources of uncertainty when modelling masonry, related to material properties, boundary conditions, quality of construction and two-dimensional interactions between mortar and unit. This paper examines the uncertainty at the mortar-unit interface with imperfections such as hairline cracks or imperfect contact conditions. These imperfections will alter the rate of liquid transport into and out of the wall and impede the liquid transport between mortar and masonry unit. This means that the effective liquid transport of the wall system will be different then if only properties of the bulk material were modelled. A detailed methodology for modelling this interface as a fracture is presented including definition of material properties for the fracture. The modelling methodology considers the combined effect of both the interface resistance across the mortar-unit interface and increase liquid transport in parallel to the interface, and is generalisable to various combinations of materials, geometries and fracture apertures. Two-dimensional DELPHIN models of a clay brick/cement-mortar masonry wall were created to simulate this interaction. The models were exposed to different boundary conditions to simulate wetting, drying and natural cyclic weather conditions. The results of these simulations were compared to a baseline model where the fracture model was not included. The presence of fractures increased the rate of absorption in the wetting phase and an increased rate of desorption in the drying phase. Under cyclic conditions, the result was higher peak moisture contents after rain events compared to baseline and lower moisture contents after long periods of drying. This demonstrated that detailed modelling of imperfections at the mortar-unit interface can have a definitive influence on results and conclusions from hygrothermal simulations.

In order to get more comprehensive operation performance on indoor environment quality (IEQ) and energy consumption, a long-time measurement and a field occupants’ satisfaction survey on IEQ performance of the first three-star-operation-certified green office building in Ningbo city of China have been conducted, and environmental energy efficiency (EEE) also has been analyzed. Moreover, IEQ and energy consumption of the green case office building are compared with other green office example buildings of the same climate zone in other literatures. The results show that the actual indoor thermal environment of the green case office building isn’t quite achieving the design goals with the Chinese standard of thermal comfort level II (GB 50736). Although indoor air quality of CO2 concentration and visual environment are consistent with the design goals, the indoor relative humidity doesn’t reach the design goal in most of the year. The questionnaire survey results illustrate that the green case building has a high occupants’ satisfaction on IEQ. The comparison results show that there is no obvious difference in indoor temperature and visual environment between the green case building and the green office example buildings in other studies. The results of occupant’s satisfaction and CO2 concentration of the green case building are better than in other studies. However, the indoor relative humidity of the green case building in every season is much higher than in other researches. Energy use intensity (EUI) of the green case building is about 56.5 kWh/m2·a, which is much lower than the constraint value of the Chinese standard. The actual performance of the green case building is also evaluated by the indicator of EEE. The results of this article can provide useful reference for green building operational performance promotion and feedback for design phase optimization.

In order to improve the comfort of the living environment, the thermal performance and temperature–humidity regulation of the exterior walls of two timber-framed structure buildings is theoretically calculated and experimentally studied in this study. Both of the two buildings are located in Nanjing, China, the hot-summer and cold-winter zone. Then WUFI is used to simulate and predict the changes of temperature, relative humidity, and water content of the two timber-framed structure buildings, to strengthen the theoretical analysis of the thermal and humidity coupling of the external walls, and to propose an optimal design scheme for the insulation and temperature and humidity regulation of the external walls. The main results show that the tested thermal conductivity is basically consistent with the predicted value, which prove that WUFI simulation can effectively predict the thermal insulation performance of the external wall. The two timber-framed structure buildings are both suitable for the cold areas, and the reasonable optimization of the design of the structure is the key to the insulation of the building wall. Timber-framed structure is proved to have good temperature–humidity regulation effect. The moisture content of the two timber-framed structure buildings is stable, and the annual temperature and winter humidity are within the appropriate humidity range, which indicates that the wall design is suitable for Nanjing hot-summer and cold-winter climate zone. Four types of wall structure indoor mold spore germinations are less likely, which is not easy to produce the mold. The above research aims to optimize the design of the energy-saving wall of the timber-framed structure and create a comfortable and healthy living environment.

Cavity walls consisting of an outer leaf, a cavity and an inner leaf are a widespread building enclosure configuration because of their good performance regarding rain tightness. To increase the drying potential, open head joints are typically provided in the brick outer leaf, creating cavity ventilation. Even though this cavity ventilation has a limited effect on the drying out of the brick veneer, it can significantly reduce the moisture levels inside the cavity. This might be crucial when the brick veneer is combined with, for example, a wooden load-bearing wall. A reliable prediction of the cavity moisture levels is hence essential. However, previous studies showed that the ventilation rate in the cavity is highly fluctuating in both magnitude and direction. That is why most numerical models simplify cavity ventilation by neglecting it, replacing it by an equivalent resistance, assuming a constant air change rate and so on. This article verifies common assumptions in numerical models to incorporate cavity ventilation behind a brick veneer cladding, by confronting the simulations with detailed field studies. The results showed that for walls exposed to driving rain and solar radiation, most simplified one-dimensional simulations do not suffice to predict the moisture content in the cavity in a reliable way. Only with two-dimensional simulations, incorporating the airflow in the cavity, a good agreement with the in situ measurements was obtained. Furthermore, the two-dimensional models showed to be able to capture the moisture gradient along with the height of the wall rather precisely.

Building energy simulations coupled with computational fluid dynamics tools have emerged, recently, as an accurate and effective tool to improve the estimation of energy requirements and thermal comfort in buildings. Building modelers and researchers usually implement this coupling in the boundary conditions of both tools (e.g. surface temperature, ambient temperature, and conductive and convective fluxes). This work reviews how the building energy simulation–computational fluid dynamics coupling has evolved since its first implementation to the present day. Moreover, this article also summarizes and discusses the research studies in which the building energy simulation–computational fluid dynamics coupling has been used to analyze building systems, building components, and building urban configurations. Implementing a building energy simulation–computational fluid dynamics coupling brings a series of benefits when compared with the conventional building energy simulation methodology, a building energy simulation–computational fluid dynamics coupling provides an improvement that ranges between 10% and 50% for estimating the building energy requirements. Moreover, the computation time to implement computational fluid dynamics with information obtained from the building energy simulation could be reduced by as well.

Three-dimensional analyses of the pore structure of building materials are becoming progressively more important in recent years. The main goal is to obtain more accurate interpretations and simulations of their properties and performances. Computed tomography has proven to be an excellent and versatile tool to perform these analyses non-destructively. The reconstruction of the pore structure is of high importance for establishing accurate models, as it plays a crucial role in determining important characteristics of building materials such as their hygrothermal, mechanical, or acoustic properties. These models allow us to better understand the results of corresponding laboratory tests and in the near future might replace these time-consuming experiments. In this article, the strengths and weaknesses of computed tomography as a data acquisition technique are examined and discussed.

Two-dimensional model of the steady-state diffusion radon transport from the soil to the ground floor of the building is developed. Radon concentration distributions in the soil and the living space are calculated at different foundation geometries. The model considers radon entry from enclosing structures, outside air, and diffusion from the soil. The radon field under the building is described. The quantitative criteria for the resistance of the building foundation to radon penetration from the soil are defined. It is found that the resistance of the ground slab to radon penetration and radon concentration in the plane of the soil structure contact have a decisive influence on indoor radon, and that the initial distribution of radon concentration in the soil changes significantly after the building erection. These changes depend on the radon potential in the soil, its radon permeability, resistance of the floor structure to radon penetration, and building geometry.