This study presents a comparative analysis of three shape parameterization techniques - explicit, particle-based, and implicit - for optimizing the thermal performance of building facades using the boundary element method. Each parameterization is optimized for two opposing thermal objectives: heat-transfer augmentation in winter and thermal insulation in summer. Then, they are quantified in terms of thermal performance, parameter parsimony, and computational efficiency. A weighted information criterion is introduced to evaluate the trade-off between parameterization complexity and thermal benefit. To ensure physical realism, geometric constraints including facade area and a minimum wall thickness are enforced, preventing mechanically fragile shapes. The analysis demonstrates that particle-based and implicit approaches achieve thermal improvements compared to the reference flat wall, while the implicit method provides the best balance between performance and computational cost. Temperature and heat-flux fields reveal that solar-exposed concave regions enhance winter heat transfer, whereas self-shaded convex formations reduce summer gains. A year-long transient simulation further confirms that a single optimized geometry can achieve more efficient thermal behavior. The results provide quantitative guidance for selecting shape parameterization strategies in facade energy optimization, highlighting the trade-offs between flexibility and efficiency.
This special issue is based on a selection of papers presented at the 9th International Symposium on Advances in Computational Heat Transfer (CHT-24), sponsored by the International Centre for Heat and Mass Transfer (ICHMT) and cosponsored by Istanbul Technical University (ITU), Rutgers University, and the American Society of Thermal and Fluids Engineers (ASTFE). It was held at ITU, Istanbul, Turkey, during May 26-30, 2024. This symposium is a continuation of a series of symposia held at various places around the world, including Cesme and Izmir, Turkey; Marrakech, Morocco; Bath, England; Piscataway, New Jersey, USA; Napoli, Italy; and Rio de Janeiro, Brazil. It focuses on computational heat transfer and covers a wide range of topics of both fundamental and applied interest.
Analytical solutions describing heat transfer in moving bed heat exchangers (MBHEs) have been previously identified through Laplace transforms. This work employs an integral transform (IT) technique to obtain the analytical solution for a counter-current parallel-plate MBHE configuration, for a heat capacity ratio less than one. The development delineates the decoupling steps for the problem, along with the identification of the auxiliary problem's orthogonality property-which is necessary to obtain a solution via ITs. As expected, the solid and fluid temperature functions identified are identical to those in the literature. A graphical analysis is also presented, illustrating the solution's behavior. For example, at a number of transfer units (NTU) of 1, the average solids outlet temperature only drops to approximately 0.5, whereas at an NTU of 10, it approaches the fluid's inlet temperature, demonstrating the exchanger's capacity to reach thermal equilibrium. Overall, the integral transform technique provides a robust approach to solving counter-flow MBHE problems and opens the door for exploring more complex configurations.
