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PV panels are vastly used for sustainable electricity generation, while they can also help the environment by improving buildings' energy consumption. The best placement for PV panels installation in buildings with flat roofs is the roof. When placed on a building's roof, PV panels affect the building's energy loads by shading the roof surface. However, the shading effect of PV panels could be different depending on the roof's thermal properties and surface materials. The combined effect of shading caused by PV panels and cool materials could significantly change the roof surface temperature, and the building energy demand. In light of the lack of studies considering this combined effect, the present study aims to evaluate the energy-saving effects of different roof materials covered with solar PV panels for a typical residential building in four cities with different climate conditions in Iran. Applying a simulation tool, Ladybug Tools have been utilized for determining the building energy loads and PV panels' power generation. The obtained results indicate that PV panels significantly affect the cooling load of the building, especially during peak times. The hottest city, Bandar-Abbas, benefits the most, with a maximum saved energy ratio (SER) of 3.4%, while the coldest city, Ardabil, has the least SER, 0.5%. Additionally, in cold and moderate climates, the highest SER occurs for the lowest R-value and solar absorption roof, while for hot climates, the highest SER occurs for the roofs with the highest R-value and the lowest solar absorption. Overall, the shading effect of PV panels becomes more significant when solar absorption is high, and the roof R-value is low. Despite the decrease in cooling energy load, PV panels might increase the heating load. Depending on the climate, this contradictory effect of the roof's thermal properties and PV panels shading should be considered in the design process of buildings. Highlights: Cities with hot-humid and cold climates have the highest and the lowest SER, respectively. PV shading is more significant on roofs with high solar absorption and low R-value. The effect of PV panels on heating load varies based on climate. [ABSTRACT FROM AUTHOR]

This paper investigates the simultaneous effect of orientation and thermal insulation of the building on each other and on the heating and cooling loads of buildings. For this aim, the heating and cooling loads of a sample building are calculated with different orientations and amounts of thermal insulation in multiple cities in Iran, which have different climatic conditions. The optimum building orientation in all the surveyed cities is when the main façade faces south, which can reduce the energy consumption of the building by 11–39%. This reduction was greater in cities with higher cooling-degree-days (CDD); which means the effect of orientation on the cooling load of a building is more significant than its effect on the heating load. Increasing the thermal insulation of the exterior walls also reduced the energy consumption of the building. 5–10% reduction in total energy consumption of the building was observed by decreasing the u-value of external walls from 0.8 to 0.4 W/m2K. This reduction was higher in cities with higher heating-degree-days (HDD) which means that the effect of insulation on heating energy consumption is more significant than its effect on cooling energy consumption. In addition, the results indicate that the building orientation and thermal insulation improve each other's efficiency. Highlights The effect of building orientation on energy consumption was investigated. Building envelope insulation effect on heating and cooling demands was investigated. The simultaneous effect of building orientation and insulation was analyzed. The results were discussed concerning different climates and climatic conditions. [ABSTRACT FROM AUTHOR]

It is crucial to optimize energy consumption in buildings while considering thermal comfort. The first step here involved an EnergyPlus simulation on a trade center building located in Tehran, Bandar Abbas, and Tabriz, Iran. A multi-objective optimization was then performed based on non-dominated sorting genetic algorithm II (NSGA-II) in jEPlus + EA to establish the building in the selected city where would benefit the most from implementing the radiant ceiling cooling system. Efforts were undertaken to choose environmentally-friendly materials. The final solution by Pareto charts resulted in a 52% reduction in energy consumption, a 37.3% decrease in cooling load, and a 17.4% improvement in comfort hours compared to the original design. Annual emission of greenhouse gas reduced as 167.67 tone of CO2 equivalent emission, 25.77 ton of CH4, and 0.2 ton of NO2. The mentioned algorithm was conducted for the first time on a trade center, including a DOAS system and radiant ceiling cooling system. Simultaneously, the environmental-friendly materials were dealt with. The procedure holds significant relevance for the design and optimization of buildings in Iran, especially wherever the climate is hot and humid. This approach offers advantages to the environment by reducing the impact on energy resources and utilizing environmentally-friendly materials. [ABSTRACT FROM AUTHOR]

Cooling energy consumption is a major contributor to various sectors in hot climates with a significant number of warm days throughout the year. Buildings account for 40% of total energy consumption, with approximately ∼30–40% of that used for cooling in geographical areas such as Iran. Energy demand for cooling is an important factor in the overall energy efficiency of electric mobility. Electric vehicles (EVs) consume ∼30–50% of energy for the air conditioning (AC) system. Therefore, the efficient management of the cooling demand is essential in implementing energy-saving strategies. Passive radiative cooling is capable of providing subambient cooling without consuming any energy. This article reviews potential applications of passive radiative cooling in reducing cooling energy for buildings. It also provides a rough estimate of the amount of energy saved when applying a radiative cool roof to a model building. It is shown that by using radiative cool materials on roofs, the share of electricity usage for cooling can be reduced to 10%, leading to a reduction in cooling load by 90%. Additionally, the potential use of radiative cool coats of various types for different EV components, such as shell/body, windows, and fabrics, is introduced. Although the prospects of the design and engineering of radiative cooling products appear promising for both buildings and EVs, further investigations are necessary to evaluate scalability, durability, and performance based on factors such as geography and meteorology. [ABSTRACT FROM AUTHOR]