Electricity consumption indicators and energy efficiency in residential buildings in GCC countries: Extensive review

In building thermal calculation, the exterior corner is a typical thermal bridge. The heat flow through this part is more concentrated and significantly larger than that through the surrounding walls. The effects of moisture on heat transfer through corners are not taken into account due to the complexity of moisture transfer. Storage and transfer of moisture will change the thermal conductivity of porous building materials and lead to latent heat flow. Neglecting the effect of moisture transfer can contribute to large errors in the calculation of heat transfer through corners, especially in the areas with high temperature and humidity. Therefore, this paper mainly analyses the process of heat and moisture transfer in the exterior corners of cooled buildings in hot and humid areas. Different outdoor environments and corner structures influence the heat and moisture transfer in the corners. Simulation results are compared with the calculations that ignore moisture effects. In addition, two typical cities, one in hot-humid area and the other in cold-dry area, are compared under cooling conditions. Finally, the correction of the average thermal transmittance of the exterior corners was determined in major cities of China. The results show that the thermal bridge effect is aggravated by moisture transfer, and heat loss at the corner is significantly affected. The impact level is related to the outdoor relative humidity, column materials, column width and insulation thickness. The correction values of the average thermal transmittance of the exterior corners (7–25.6%) in hot and humid areas of China are generally higher than that in other areas.

Effect of moisture transfer on heat transfer through exterior corners of cooled buildings in hot and humid areas

The main focus of the article is to investigate the effects of radiation on PCM advantageousness in buildings. Numerical methods were used to estimate the intensity of radiation on horizontal (roof) and vertical (walls) surfaces and then its effect was applied as heat flux in boundary conditions. To examine PCM, the heat exchange (HE) through horizontal and vertical surfaces was determined and compared with the surfaces without PCM. For surfaces without PCM, the highest HE was for roof (4348 kWh/year) and followed by east (3919), west (3906), north (3656) and south (3520 kWh/year) walls. By adding a 5 cm layer of PCM to the outermost layer, HE through roof dropped by 34% while this figure was 23.4% for east wall and followed by 23.2% (west), 18.9% (north) and 16.7% (south). To enhance the effect of PCM, its installation location was examined in four cases and it was found that if PCM is mounted in the outermost layer, there is the most energy-saving (i.e., 4576 kWh/year). Finally, adding a solar air heater was led to more energy-saving by 325 kWh/year. • Effects of phase change materials to reduce the energy demands in buildings. • Examine the solar radiation air heater in a building equipped with PCM. • Adding a solar air heater was led to more energy-saving by 325 kWh/year. 

Integration of a solar air heater to a building equipped with PCM to reduce the energy demand

Thermal mass impact on energy consumption for buildings in hot climates: A novel finite element modelling study comparing building constructions for arid climates in Saudi Arabia

Thermal envelope analysis for new code compliance of Saudi Arabian dwellings

New energy-efficiency regulations have been established and applied in many Gulf countries to improve building energy performance. Thermal bridging reduces the building envelop performance, and this is not a focus of these regulations. This paper investigates the concrete construction of residential housing in hot climates and identifies more sustainable concrete construction methods. Both experimental and numerical methods are used to identify the impact of thermal bridging. Using finite element analysis, the impact of solar radiation on a building’s thermal bridging was analyzed. It is identified as an essential element for accurate modelling of bridging across concrete in a hot climate. The FE model was evaluated against monitored data and assessed using common statistical indicators. The results show that the heat loss across uninsulated cast in situ structural elements is more than double the heat loss across portions of insulated walls. Moreover, neglecting solar radiation on the westerly façade can result in errors of >50%. Additionally, the impact of thermal bridging is increasingly evident when accounting for solar radiation. Modelling studies show that the impact of thermal bridging could be reduced by up to 73% by covering the structural elements with external insulation. Compliance with the various codes of the different Gulf states can be achieved through externally insulating with between 40 and 80 mm, and this is shown to have wide-ranging benefits in enhancing building energy efficiency.

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Essam Alayed

Papers

Thermal envelope analysis for new code compliance of Saudi Arabian dwellings

Thermal mass impact on energy consumption for buildings in hot climates: A novel finite element modelling study comparing building constructions for arid climates in Saudi Arabia

Solutions for Exposed Structural Concrete Bridged Elements for a More Sustainable Concrete Construction in Hot Climates