Most concrete employs organic phase change materials (PCMs), although there are different types available for more specialised use. Organic PCMs are the material of choice for concrete due to their greater heat of fusion and lower cost in comparison to other PCMs. Phase transition materials are an example of latent heat storage materials (LHSMs) that may store or release thermal energy at certain temperatures. A phase transition occurs when a solid material changes from a solid state to a liquid state and back again when heat is added or removed. It is common knowledge that adding anything to concrete, including PCMs, will affect its performance. The goal of this review is to detail the ways in which PCMs affect certain concrete features. This overview also looks into the current challenges connected with employing PCMs in concrete. The review demonstrates a number of important findings along with the possible benefits that may pave the way for more research and broader applications of PCMs in construction. More importantly, it has been elucidated that the optimum PCM integrated percentage of 40% has doubled the quantity of thermal energy stored and released in concrete. Compared to conventional concrete, the macro-encapsulated PCMs showed thermal dependability, chemical compatibility, and thermal stability due to delaying temperature peaks. Furthermore, the maximum indoor temperature decreases by 1.85 °C and 3.76 °C in the test room due to the addition of 15% and 30% PCM composite, respectively. Last but not least, incorporating microencapsulated PCM has shown a positive effect on preventing freeze-thaw damage to concrete roads.

The use of phase change materials (PCMs) has become an increasingly common way to reduce a building’s energy usage when added to the building envelope. This developing technology has demonstrated improvements in thermal comfort and energy efficiency, making it a viable building energy solution. The current study intends to provide a comprehensive review of the published studies on the utilization of PCMs in various constructions of energy-efficient roofs, walls, and ceilings. The research question holds massive potential to unlock pioneering solutions for maximizing the usefulness of PCMs in reducing cooling demands, especially in challenging high-temperature environments. Several issues with PCMs have been revealed, the most significant of which is their reduced effectiveness during the day due to high summer temperatures, preventing them from crystallizing at night. However, this review investigates how PCMs can delay the peak temperature time, reducing the number of hours during which the indoor temperature exceeds the thermal comfort range. Additionally, the utilization of PCMs can improve the building’s energy efficiency by mitigating the need for cooling systems during peak hours. Thus, selecting the right PCM for high temperatures is both critical and challenging. Insulation density, specific heat, and thermal conductivity all play a role in heat transfer under extreme conditions. This study introduces several quantification techniques and paves the way for future advancements to accommodate practical and technical solutions related to PCM usage in building materials.

Energy security refers to a country’s capacity to provide the energy resources essential to its wellbeing, including a reliable supply at an affordable costs. Economic growth and development cannot occur without access to reliable energy sources. Energy availability is a proxy for a country’s standard of living and a key factor in its economic development and technical progress. Solar power is the most reliable and cost-effective option when it comes to meeting the world’s energy needs. Solar-powered cooling systems are one example of how solar energy may be used in the real world. Solar-powered air conditioners have become more popular in recent years. The problems caused by our reliance on fossil fuels may be surmounted with the help of solar cooling systems that use solar collectors. Solar cooling systems may utilize low-grade solar energy, making them popular in the construction industry. Solar cooling systems powered by photovoltaic–thermal (PVT) collectors have been the subject of much research to improve the thermodynamic and economic performance of solar cooling systems. This research focuses on exploring the potential of solar-generated heat for use in cooling systems. This study will also examine the current challenges involved with using solar energy in cooling applications, as well as the possible benefits that may help pave the way for more research and greater employment of heat gain from the solar system in various cooling applications.

The current research aims to study the overall performance of a solar air ‎heater ‎integrated system (SAHIs) under the Iraqi weather circumstances throughout the utilization of metallic fiber as a new method in absorbing the heat. Several experiments were conducted using a double pass triangular plate and compared with metallic fiber (SAH) as an absorber surface. These experiments were performed during February, March, and April of 2019 over the air mass flow rate range (0.0043–0.0125 kg/s) and depending upon environmental circumstances. Results evinced that the ultimate daily thermal efficiency of the solar air ‎heater was (63.77%) and (74.2%) with a triangular absorber plate and metallic fiber, correspondingly when using (0.012 kg/s) air mass flow rate and the instantaneous thermal efficiency of (SAH) increased from (30%) to (80%) and (30%) to (95%) when the air mass flow rate was increased from (0.0043 kg/s) to (0.0125 kg/s) and from (0.043 kg/s) to (0.0123 kg/s) for triangular absorber plate and metallic fiber, correspondingly. At an air mass flow rate of (0.012 kg/s), the temperature of the ultimate absorber surface and the outlet of air was (58°C) and (35°C) for triangular absorber plate, respectively and (49°C) and (44.5°C) for metallic fiber correspondingly. Also, the results demonstrated that the daily and instantaneous thermal efficiency of (SAH) with the metallic fiber was higher than that with a triangular absorber plate at the similar air mass flow rate. Additionally, the temperature discrepancy between the absorber surface and the outlet air when employing metallic fiber was less in comparison with the use of triangular absorber plate, and the temperature difference between inlet and outlet air temperature decreased when the air mass flow rate was increased. Moreover, the present study manifested a higher overall thermal efficiency than those obtained by previous studies. Abbreviations: HE: Heat exchanger; SAH: Solar Air Heater; SAHs: Solar Air Heaters; SAHIS: Solar Air ‎Heater ‎Integrated System