In recent years, the construction sector has significantly increased demand for new building materials that can reduce environmental impact and promote sustainable design strategies. In this context, the use of earth for construction purposes has received increasing attention in the last decade owing to its low environmental impact, local availability, and recyclability. The literature survey indicates that the incorporation of waste materials in the production of unfired earth bricks holds significant potential to partly substitute earth by satisfying specific requirements. Additionally, utilizing these waste materials for the development of unfired earth bricks provides a solution that conserves natural resources, reduces energy consumption, and contributes to efficient waste management. The aim of this paper is to present an overview of recent research focusing on the recycling of various types of waste into eco-friendly unfired earth bricks. Also, the effect of the incorporation of waste materials on the thermal and mechanical properties of unfired clay bricks is reviewed. The most common results, organized based on the type of additive (industrial or agricultural waste), are shown and discussed.

Thermal energy storage (TES) using phase change materials (PCMs) is an innovative approach to meet the growth of energy demand. Microencapsulation techniques lead to overcoming some drawbacks of PCMs and enhancing their performances. This paper presents a comprehensive review of studies dealing with PCMs properties and their encapsulation techniques. Thus, it is essential to critically examine the existing techniques and their compatibility with different types of PCMs, coating materials, and the area of application. The main objective of this review is to describe each microencapsulation process and to determine different factors that influence the performance of resulting microcapsules. Microencapsulation efficiency, as well as the limitation of each technique, are investigated, and optimum operating conditions of each process are highlighted. Furthermore, up-to-date studies of multifunctional PCMs microcapsules development with enhanced performances and new application directions are also presented. This review aims to be a useful guide for future researches dealing with low thermal energy storage applications of PCMs microcapsules.

In hot dry regions, the building envelope receives abundant solar radiation, which contributes to heat stress and indoor thermal discomfort. To mitigate overheating inside spaces, cooling is the main basic requirement during most of the year. However, due to the harsh climatic conditions, buildings fail to provide passively the required comfort conditions. Consequently, they are fully dependent on-air conditioning systems, which are huge energy consumers. As roofs are exposed to the sun throughout the daytime, they are estimated to be the main source of heat stress. In return, they can contribute significantly to achieve optimum comfort and energy savings when efficient design strategies are used in an early design stage. To examine the potential for cooling load reduction and thermal comfort enhancement by using cooling roof techniques in residential buildings, a study was performed in the city of Biskra (southern Algeria). Accordingly, an in-field measurement campaign was carried out on test-cells during five days in summer. Three different cooling roof techniques were addressed: (a) cool reflective white paint (CR), (b) white ceramic tiles (CT) and (c) a cool-ventilated roof (C-VR). These roofing alternatives were investigated by monitoring both roof surface temperatures and indoor temperatures. Comparative analysis showed that a cool-ventilated roof is the most efficient solution, reducing the average indoor temperature by 4.95 °C. A dynamic simulation study was also performed based on TRNSYS software to determine the best roofing system alternatives in terms of thermal comfort and energy consumption, considering the hottest month of the year. Simulation tests were run on a base-case model representing the common individual residential buildings in Biskra. Results showed that a double-skin roof combined with cool-reflective paint is the most efficient roofing solution. By comparison to a conventional flat roof, meaningful improvements have been achieved, including reducing thermal discomfort hours by 45.29% and lowering cooling loads from 1121.91 kWh to 741.09 kWh.

This paper deals with natural convection flows evolving inside an ended and differentially heated cavity, which is filled either with an air or an air–CO₂ mixture. The investigation was conducted through the laminar regime to analyze buoyancy ratio changes' effect on heat and mass transfers both in aiding and opposing flows. The thermal Rayleigh number was varied from 10³ to 10⁷. Streamlines, isotherms, iso-concentrations, and local and average Nusselt and Sherwood numbers are provided to demonstrate the convective flow induced. The governing equations are solved by finite volume method using SIMPLEC algorithm to handle the pressure–velocity coupling. The buoyancy ratio effect on dynamic, thermal, and mass fields is noteworthy, exhibiting both the competition between thermosolutal forces and fields' stratification. From the results, it turned out that, in general, when the buoyancy ratio is: (1) positive, thermosolutal buoyancy forces are cooperative, (2) nil, solutal buoyancy forces are weak and the flow is merely thermoconvective, (3) negative and greater than −1, buoyancy effects are competing and thermal convection dominates, (4) −1, buoyancy effects are canceled and heat and mass transfers are driven only by diffusion, and (5) less than −1, buoyancy forces compete with a dominant solutal convection.