Bridging the Indoor Thermal Environment Gap: Rethinking Thermo-Physical Properties for Building Energy Efficiency

Submission Deadline: 10 April 2026 View: 200 Submit to Special Issue

Guest Editors

Assist. Prof. Mohammed W. Muhieldeen

Email: al-gailani@ucsiuniversity.edu.my

Affiliation: Mechanical Engineering Department, Faculty of Engineering, Technology and Built Environment, UCSI University, Kuala Lumpur, 56000, Malaysia

Homepage:

Research Interests: saving energy in buildings, thermal comfort, indoor air quality, heat load in buildings, natural ventilation, thermal insulation, passive cooling method, CFD analysis, energy efficiency, and heat transfer

Dr. Xin Yin

Email: eddieyin25@yahoo.com

Affiliation: Architectural Engineering School, Sichuan Water Conservancy College, No. 366 Yonghe Avenue, Chongzhou, 611843, China

Homepage:

Research Interests: building energy modelling, energy efficiency, computational fluid dynamics (CFD), thermal comfort, natural ventilation, heat transfer, and thermodynamics

Summary

Extreme outdoor conditions, such as urban heat islands, pollutant dispersion, and thermal discomfort, push more people indoors, resulting in people spending over 90% of their time indoors. Passive heat storage within indoor spaces is a promising solution to enhance building energy flexibility, relying on precise control of transient indoor temperatures. However, the temperature must be kept within occupants' thermal comfort limits. Consequently, the indoor environment becomes critically important for both human health and efficient energy management. Key factors influencing this demand include the properties of internal mass materials, element thickness, quantification of internal thermal mass, and the effective heat capacity of internal masses. Viewing thermal mass within the indoor context opens new opportunities for innovative energy technologies, particularly by leveraging the heat capacity of internal building materials.

Highlighting furniture and additional mass present in a real, occupied building is vital for optimizing energy performance, reducing environmental impact, and enhancing indoor thermal comfort. This special issue provides a platform for recent research focused on rethinking the interaction between internal thermal mass and the indoor environment. Researchers, engineers, and practitioners are encouraged to submit original/review work that advances the boundaries of numerical modeling, experimental studies, and energy optimization in the internal thermal environment.

Topics of interest include, but are not limited to, the following:
• Internal mass modeling.
• Practical implementations of integrated thermal and storage technologies in room environments.
• Optimization models for achieving a healthy and energy-efficient indoor environment.
• Phase Change Materials for building energy storage.
• AI and machine learning models for optimizing the indoor thermal environment.
• Advanced numerical modeling in indoor thermal comfort and energy efficiency.
• Innovations in energy-saving technologies for thermal energy storage.

Keywords