Vol. 3 No. 1 (2025): Advanced Technologies in Smart and Sustainable Energy for Carbon Neutrality Transformations

Article

• Open Access

  Article ID: 249

  

  Investigation of hygrothermal behavior of a novel bio-based panel: Experiment and numerical simulation

  by Yaping Zhou, Abdelkrim Trabelsi, Li Xiang, Mohamed El Mankibi

  Clean Energy Science and Technology, Vol.3, No.1, 2025;
  71 Views

  DOI: https://doi.org/10.18686/cest249

  Straw composites, owing to their low carbon footprint and favorable hygrothermal properties, are becoming a promising alternative insulation material for buildings in order to promote energy saving and occupants’ comfort. However, the heat and moisture characteristics of straw composites at the material scale and under steady-state condition are insufficient for a thorough assessment of their performance as a building component in actual service conditions. This study focused on the hygrothermal performance of a novel bio-based wall made with a rice straw–alginate composite material. The temperature and relative humidity profiles within the wall were monitored under various boundary conditions. The inverse analysis method was proposed to determine liquid water permeability. In in a dynamic test, compared with the model of coupled heat-and-moisture transfer (CHM), the transient heat transfer model predicted temperature profiles with higher errors and underestimated total heat flux by up to 30.6%. Also, under the dynamic condition, the CHM model with liquid water transport showed decreased mean absolute errors by 61%, 57% and 8% at depths of 28 mm, 36 mm and 64 mm, respectively, compared with those predicted by the CHM model without liquid water transport. Both vapor transport and liquid transport seemed to be essential when modeling thermal transfer and moisture transfer through the wall.

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• Open Access

  Article ID: 334

  

  Optimal control method for flexible loads in thermally activated buildings

  by Xiaochen Yang, Ruizhi Wang, Zhenya Zhang, Ping Wang, Dingzhou Liu, Yixuan Jiang

  Clean Energy Science and Technology, Vol.3, No.1, 2025;
  36 Views

  DOI: https://doi.org/10.18686/cest334

  As the penetration of renewable energy in the energy system continues to rise, the intermittency and stochasticity of energy supply have become increasingly significant, posing challenges to the dynamic coordination between energy supply and demand. Building thermal mass, with its inherent heat capacity, offers substantial energy storage potential, presenting a cost-effective alternative to traditional active energy storage methods. The activation and precise control of flexible energy from the building's thermal mass, has become a critical area of research. In this paper, based on a case floor-type thermally activated building system (TABS), the methods and constraints of simulating the energy flexibility potential on the demand side of the building were analyzed. By developing model predictive control (MPC) strategies, including white-box MPC, grey-box MPC, and black-box MPC, this study compared and assessed the control performance in terms of room temperature, accumulated energy cost, and the utilization efficiency of energy flexibility. Compared with the traditional rule-based control method, the MPCs showed better performance in room-temperature control, operation economics, and efficiency of flexible-load utilization, effectively saving energy costs by up to 20% and improving flexibility utilization by nearly 40%. Moreover, based on the performance comparison of the MPCs, white-box MPC performed optimally in terms of room-temperature control, while grey-box MPC was more effective in reducing energy costs and improving energy flexibility. The findings of this paper can provide theoretical insight for the efficient utilization of energy flexibility from building thermal mass and the selection of control methods.

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