Evaluating Thermal Performance of Modular Prefabricated Educational Building Construction Materials in Saudi Arabia

Abstract

The Kingdom of Saudi Arabia (KSA) faces a significant problem of high energy consumption driven by its hot climate, which gives rise to heavy reliance on cooling systems. Globally, KSA ranks among the countries with the highest electricity use per capita, having reached 11.91 megawatt-hours (MWh)/capita, compared to the world average of 3.47 MWh/capita, in 2023. To address the issue of high energy consumption, Saudi Arabia’s Vision 2030 includes a target of improving building energy performance by 30% and a commitment to achieving net-zero CO2 emissions by 2060. Additionally, KSA’s rapid population growth (projected to rise from 34 million to 55 million by 2030) will drive higher energy demand following the anticipated increase in housing and associated infrastructures. Modular prefabricated buildings offer a promising way forward to address this issue, given their shorter construction time and lower costs. However, their energy performance remains underexplored in KSA, particularly in the education sector. Attention to building envelope thermal performance in hot and humid climates, in particular, has been limited. This study contributes to addressing a research gap where limited studies have examined the thermal performance of modular educational buildings in KSA, particularly their envelope performance in hot and humid climates. Therefore, the study aims to evaluate and improve the building thermal performance of modular buildings in Jeddah city, with a focus on improving building envelope materials to improve Indoor Air Temperature (IAT) and reduce energy consumption. The study is based on a real case at Jeddah University campus, with the entire performance evaluation conducted under free-run conditions. It comprised two methodological phases: First, field measurements were conducted during winter and summer 2023 to record indoor and outdoor air temperatures, solar radiation and surface temperatures; second, an energy simulation model was developed in DB and validated against the measured IAT. Statistical metrics, including CVRMSE and RMSE were applied to ensure model accuracy and establish a reliable baseline. Several envelope improvement strategies were then tested including (thermal insulation, wall material upgrades, phase change materials, glazing types, window-to-wall ratios and external shading), with each measure assessed based on its impact on IAT and total energy consumption. The findings showed that Phase change materials had the strongest impact, reducing mean-IAT by 5.1°C in summer and 2.3°C in winter. When all measures were combined with an 18°C cooling setpoint, total energy use decreased by 24%, and cooling loads by 28%. Further optimisation with LED lighting and a 24°C setpoint achieved up to 76% reductions in energy use and CO2 emissions. The optimised model was also tested across five Saudi cities, i.e. Riyadh, Dharan, Jazan, Tabuk and Abha, with energy savings ranging from 69% (in Jazan) to 83% (in Abha). This study supports KSA’s Vision 2030 by offering validated strategies for improving the building thermal performance of modular educational buildings in hot and humid climates. The findings demonstrate that combining multiple building-envelope improvement measures is essential for improving energy efficiency and indoor air temperature. The research also offers scalable, climate-responsive solutions to reduce energy demand and CO2 emissions across the Kingdom’s diverse climate zones. Overall, This study contributes new insights into the design and practical application of integrated envelope strategies for new and existing modular prefabricated educational buildings, supporting the advancement of energy-efficient, scalable, and sustainable prefabricated construction solutions in KSA.