Exergetic Performance Assessment of Optimally Inclined BIPV Thermal System by Considering Cyclic Nature of Insolation

The structural and architectural elements of building-integrated photovoltaic-thermal (BIPVT) systems are made up of photovoltaic (PV) modules and these are required to be fixed at an optimum inclination angle for generating maximum exergy. This work presents an attempt to determine the amount of exergy generated by an optimally inclined double-storied BIPV thermal system by considering the actual cyclic nature of insolation, surrounding air temperature, PV cell temperature, intermediate slab temperature, and the chamber temperature. The insolation value, which is computed by an anisotropic sky model along with these cyclic variables, is used for solving the set of governing differential equations for evaluating the exergy of the system. Other influencing parameters of the BIPV thermal systems such as air changes in both chambers, packing factor of PV module, the orientation of PV module, and thickness of the intermediate slab are considered for finding its effect on the total exergy of the system. Numerical results show that for packing factor more than 0.6, there is no significant change in total heat exergy with respect to the inclination angle. For packing factor more than 0.3, the generation of electrical exergy exceeds the heat exergy, and the overall exergy of BIPVT system decreases with rise in packing factor (βm) up to 0.3 and then rises nonlinearly.

Performance-Based Evaluation of a Double-Deck Tunnel and Design Optimization

The double-deck tunnel is well known as smart infrastructure because multiple sections can be used for various purposes. Although the stability of a double-deck tunnel is mainly governed by the intermediate slab, the effect of various governing factors on tunnel structural stability has not been fully investigated. In this study, performance-based evaluation method for a double-deck tunnel is suggested as a three-dimensional matrix considering the life cycle of a double-deck tunnel. Moreover, a customized software for design and maintenance of a double-deck tunnel is developed. A structural analysis solver based on a beam–spring model for a double-deck tunnel was embedded in this code. The effects of connection type as well as depth of tunnel, ground stiffness and traffic load on structural behavior of tunnel were investigated. From the analysis, it was found that the connection type between segment lining and intermediate slab significantly affects the behavior of segment lining: simply connected condition causes lesser stress and moment than fully fixed condition. The deeper the tunnel depth, the greater the member force of segment lining. In addition, as both the tunnel depth and the ground stiffness increase, the influence of connection type on the structural stability of the double-deck tunnel becomes insignificant.

Three-Body Heat Transfer Between Anisotropic Magneto-Dielectric Hyperbolic Metamaterials

We investigate the near-field (NF) radiative heat transfer of the three-body system consisting of anisotropic magnetodielectric hyperbolic metamaterials (AMDHMs), which can support coupled surface phonon polaritons (SPhPs) and hyperbolic modes for both p and s polarizations. We numerically demonstrate that the NF heat transfer between two AMDHMs bodies can be further enhanced by inserting an AMDHMs slab. Due to the loss in AMDHMs, there exists an optimum thickness of the intermediate slab to maximize the NF heat flux flowing to the receiver for a fixed gap distance. Results obtained from this work will facilitate investigations of the NF heat transfer involving magnetic hyperbolic metamaterials.