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Buildings consume around 32% of the produced energy, worldwide and around 19% of the greenhouse gas emissions are related to them. It makes the buildings one of the largest energy consumers and one of the major sources of greenhouse gases emission. HVAC systems are one of the largest consumers of energy in buildings. In hot arid climates, cooling systems used in buildings impose a large pressure on the power grid, which may lead into blackouts. In order to address this problem, several approaches have been examined. Thermal energy storage, in particular, latent heat storage using phase change materials (PCM) has been notably considered in construction applications because of high energy storage densities. In this paper, the effect of using PCMs on energy consumption and peak load demand of a sample building is studied. Besides, impacts of precooling as a peak load shifting strategy is also investigated in presence of PCMs on the energy consumption of the sample building. The study was carried out for the weather condition of Kerman, Iran and the simulation is performed by TRNSYS software. Three types of phase change materials were investigated for two different scenarios. The simulation was performed at two stages and two modes for each stage which each mode had its own set point temperature. The application of PCMs was considered at the first stage and precooling added to the simulation at the second stage. The results of the first stage showed that employing PCMs in the studied building reduces the cooling load up to 13%. With precooling, the cooling load reduction was up to 16%. At all stages peak loads decreased with maximum 14% at the first stage and 42.5% at the second stage. It has been showed that the solid–liquid phase change temperature of the PCMs close to the selected room temperature, have significant impact on the performance of PCMs for reducing the energy consumption of the sample building compared to the other thermal properties. Due to the low electricity prices in Iran, despite the high amounts in load reduction achieved by each strategy, the cost savings during hot months of the year was not significant. [ABSTRACT FROM AUTHOR]

Researchers have proposed and studied many methods to reduce energy consumption in the construction sector. However, simultaneous use of phase‐change material (PCM) and green roofs in a building with double‐ or triple‐skin facades (DSF or TSF) has not been analyzed to date. Accordingly, this is the first study to evaluate and compare the design of two scenarios combining passive and active methods, including (1) simultaneous use of a DSF, PCM, green roof, and photovoltaics (PV), and (2) simultaneous use of a TSF, PCM, green roof, and PV in hot arid steppe‐dry mid‐latitude (Tehran) desert biome‐dry tropical (Yazd), and mild‐humid climate (Amol) in Iran. It was found that the first scenario works better in reducing the heating load and the second scenario is more effective in reducing the cooling load. The results indicate that the reduction of the annual heating load in the first scenario was 49, 45.1, and 40.7 MWh/year in Tehran, Yazd, and Amol, respectively, and that the reduction of cooling load in the second scenario was 48.4, 31.9, and 16 MWh/year in Yazd, Tehran, and Amol, respectively. The 14 different modes of combining these passive methods and PV system were then compared. The results indicate that the second proposed scenario caused the lowest annual energy consumption compared to that of other modes and saved 70% of annual energy consumption. Consequently, the effect of leaf area index, cavity width, and orientation that are selected as primary parameters affecting the thermal performance of the mentioned methods on this scenario were investigated. [ABSTRACT FROM AUTHOR]

In the present study, a five‐stage solar still is investigated in which paraffin wax was considered as the phase change material. Considering the climatic conditions of Iran and its locating in an arid area and shortage of freshwater resources, it is essential to produce freshwater from saline water resources. So, herein, a multi‐stage solar still as a commonly used water desalination apparatus with paraffin wax phase change materials was designed, fabricated, and tested. On the back of the collector absorber, the paraffin wax was applied for storing the additional solar energy. The results showed that the application of paraffin‐wax phase‐change agent leads to a 15% increase in freshwater production. The quantity of water generated was also studied in the flow rates of 0.7, 1.3, and 1.8 L/min with and without phase change materials. The results showed that the highest quantity of water produced is obtained in the 1.3 L/min flow rate. Finally, the quantity of water generated in the five stages of the desalination process was separately measured and found that the water produced in the first stage was 70% of the total water. [ABSTRACT FROM AUTHOR]

In order to attain an efficient path into the enhancement of the sustainable conservation and management of energy resources in the buildings and residential sections, efforts by all relevant institutions in the area of energy are essential and primitive. Hence, the development of the energy supply model in the building and the provision of fundamental solutions in this area is rudimentary. The key to any program related to this matter is to boost and extend energy efficiency and energy resource management. According to the global statistics and processed data, the residential sector accounts for 34 percent of the total energy consumption in Iran, which is the highest energy consumption compared to all existing sectors; therefore, immeasurable research has been done on optimizing energy usage in the building sector. One of the most efficient energy optimization methods can be achieved by using energy storage materials in the outer walls of the buildings. In this project, a research‐based residential building is considered as a case to investigate for energy optimization. In the first stage, the building is simulated and the energy consumption of the building is measured. Afterward, with actual measurements, real consumption is approximated and compared with the results of the software. After verifying the software data, the insulation is simulated in the software and the outcomes of using this insulator are investigated to reduce energy consumption. Energy storage materials are considered as a type of phase‐change material. These materials have the same characteristics which is having a different melting point and, by capturing and losing heat at design temperatures, they can help maintain energy inside the building that is how they can be considered as an insulator. Within the appropriate software which is Design‐Builder, miscellaneous types of these materials are available with various features. The final results point out that the use of this material saves up to 30% of the heating energy and about 8% in the cooling load of the building. [ABSTRACT FROM AUTHOR]