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A key challenge in lake ice modeling is quantifying the heat flux from water to ice. In shallow Central Asian lakes, where the seasonal ice cover mainly consists of columnar congelation ice, sunlight penetration enables strong interactions between ice and water. The evolution of ice cover in Lake Ulansu (Ulansuhai, Wuliangsuhai) in northern China was investigated via the High‐resolution Thermodynamic Snow and Ice (HIGHTSI) model. Atmospheric forcing was provided by calibrated ERA5 reanalysis data, and the initial freeze‐up dates were identified from remote sensing observations. A new parameterization of the water–ice heat flux (Fw), which is suitable for shallow lakes, was proposed as Fw = aQsw + b, where Qsw represents the solar heating of water and a and b are fitted coefficients. The model showed high correlations (>0.9) and low errors (<5 cm for ice thickness; <2°C for ice temperature) with respect to field observations. Throughout the ice season, long‐ and shortwave radiation promoted ice growth and melting, respectively. Surface melting and sublimation accounted for 9.5% and 9.8%, respectively, of the total ice decay, and the water–ice heat flux Fw = −17.5 ± 13.0 W m−2 was critical for simulation accuracy. Furthermore, despite the shallow depth, the lake released over 100 W m−2 of heat into the atmosphere for 2 days after break‐up. These findings highlight the climatic sensitivity and support sustainable water resource management of more than 10,000 shallow lakes in Central Asia.

Large pelagic fishes often dive and surface repeatedly as if they were airbreathers, raising a question about the functions of these movements. Some species (e.g., bigeye tuna, ocean sunfish) apparently alternate foraging in deep cold waters and rewarming in shallow warm waters. However, it is unclear how prevalent this pattern is among species. Blue sharks are the widest-ranging pelagic shark with expanded vertical niches, providing a model for studying foraging–thermoregulation associations. We used electronic tags, including video cameras, to record the diving behaviour, muscle temperature, and foraging events of two blue sharks. During repeated deep dives (max. 422 m), muscle temperature changed more slowly than ambient water temperature. Sharks shifted between descents and ascents before muscle temperature reached ambient temperature, leading to a narrower range (8 °C) of muscle temperature than ambient temperature (20 °C). 2.5-h video footage showed a shark catching a squid, during which a burst swimming event was recorded. Similar swimming events, detected from the entire tag data (20 − 22 h), occurred over a wide depth range (5 − 293 m). We conclude that, instead of alternating foraging and rewarming, blue sharks at our study site forage and thermoregulate continuously in the water column. Furthermore, our comparative analyses showed that the heat exchange rates of blue sharks during the warming and cooling process were not exceptional among fishes for their body size. Thus, behavioural thermoregulation linked to foraging, rather than enhanced abilities to control heat exchange rates, is likely key to the expanded thermal niches of this ectothermic species.

Currently used TEG modules have low efficiency of about 5%. The energy generated by the TEG module depends on the temperature difference between the module surfaces. Heat exchange between the heat source and the module surface takes place through the contact between two rough solid surfaces. This creates contact resistance. It can be reduced by using a substance filling the empty spaces between the contact surfaces and applying pressure. During the tests, the efficiency of electricity generation with a thermoelectric generator was measured (TEG) at various pressure forces. The tests were carried out at a pressure force of 250 N, 500 N, 750 N and 1000 N. The selected values of pressure do not exceed the limit value arising from the thermoelectric generator (TEG) design. A copper element constituting the heat source was heated in a furnace. Next, it was pressed at an adequate force to the generator, which was placed on a water cooler. The impact of conductive materials placed between the faces of the heat source and the TEG on the generation of electricity was examined. At low forces, the use of a thermal pad as an intermediary substance does not result in improved heat transfer in the heat source—TEG generator system. Better filling of voids is provided by thermally conductive paste due to its properties.

In the present research paper, the thermal performance of helical ground air heat exchanger (HGAHE) has been experimentally analyzed under Saharan climate conditions during summer season. A flexible PVC pipe with a diameter of 0.06 m and a length of 30 m has been arranged as a helical-coil layout to design the HGAHE, and it is inserted into a borehole of 5 m depth. The study acknowledges that a drop as high as 11.0 °C in air temperature can be achieved with an air velocity of 10 m s −1 and an inlet air temperature of 38 °C. The study also revealed that, by incrementing the air velocity from 10 to 20 m s −1 , the heat exchange rate of the HGAHE system increases by 158% after 3 h of operation time; however, the efficiency of the HGAHE decreases by 21.51%. Moreover, thermal performance derating factor (TPDF) increments with increasing the operation time and air velocity. After 3 h of operation time, the highest TPDF is attained as 0.27 with a velocity of 20 m s −1 , whereas the lowest TPDF is observed as 0.14 for a velocity of 10 m s −1 .

Many energy systems demand heat transfer at high temperatures to keep up with high demand for power, so high‐temperature material that can perform and last under these harsh conditions is needed for heat exchangers. The engineering requirements for these high‐temperature heat exchanger material call for high thermal conductivity, high resistance to fracture, high resistance to creep deformation, environmental stability in environments associated with the application, and high modulus of elasticity while maintaining low cost to make and maintain. Naturally, ceramics are a good solution for this endeavor. In the past, high‐temperature heat exchangers made from ceramics have been used. We provide examples of ceramics in relevant heat exchange applications and provide motivation where additive manufacturing (AM) can improve efficiency. AM for the relevant material is under development, and we provide insight on the AM of ceramic materials and examples of AM heat exchangers keeping cost in mind. The motivation of the review paper is to provide a framework for material and manufacturing selection for high‐temperature heat exchangers for AM to keep up with the demand for better efficiency, better material, better manufacturing, and cost moving forward with AM technology in high‐temperature ceramic heat exchangers. High temperature heat exchangers may be designed from ceramics to achieve higher performance, and various materials and manufacturing techniques can help achieve highly efficient high temperature systems.

In this paper, the important role played by the local air-sea heat exchange in the east–west oscillation of the Western Pacific subtropical high (WPSH) on the sub-seasonal scale is revealed. First, the east–west oscillation index is defined for the WPSH using the relative vorticity field. The index can well characterize the sub-seasonal east–west oscillation of the WPSH, and it has a significant sub-seasonal cycle of 10–30 days. During the westward events, there is a cold sea surface temperature (SST) anomaly in the WPSH and its west side at the early stage of westward WPSH extension, and the cold SST anomaly makes the low-level atmosphere relatively stable, which is conducive to the generation of abnormal anticyclone, and then leads to the westward extension of the WPSH. During the westward WPSH extension, the convective activity is further suppressed; therefore, the water vapor evaporation and the cloud cover are reduced, and the net heat flux received by the ocean surface increases, eventually leading to the rise of SST. At the late stage of the westward extension, the continually enhanced warm SST causes instability of the low-level atmosphere, weakens the abnormal anticyclone, and then leads to the eastward retreat of the WPSH. Thereafter, the enhanced convective activities causes the increase of latent flux and cloud cover in the atmosphere, as well as the decrease of solar radiation flux. As a result, the warm SST anomaly weakens. The situation is the opposite for the eastward events. During the eastward or westward movement of the WPSH, beside the influence of the air-sea interaction in the WPSH region, the northward and northwestward propagation of the OLR anomaly in the tropical Indian Ocean and the Western Pacific respectively, and the SST anomaly in the equatorial western Pacific also have some influence on the WPSH east–west movement. The process of air-sea interaction is similar in the early and late summer, but the intensity of each meteorological factor is stronger in the early summer than that in late summer, which indicates that the air-sea interaction is more obvious in the early summer.

The Kuroshio takes a large meander (LM) path since summer of 2017 for the first time since the 2004–2005 event and is the sixth LM event since 1965. It has been commonly recognized that a cool water pool is distributed broadly in the inshore region between the Kuroshio and southern coast of the Tokai district, Japan, during the LM periods. By using the recently-developed 1-km high-resolution sea surface temperature data, here we show marked coastal warming off the Tokai district during the LM periods, despite the Kuroshio not passing through the coastal area. The archived temperature-salinity profiles reveal that large positive anomalies off the Tokai district exist not only at the sea surface but also below 300 m and the water properties of which are those of the offshore Kuroshio water. The warm, salty waters are transported inshore by the westward Kuroshio which bifurcates at around 138° E, 34° N, during the LM path periods. We detect an increased upward heat release via turbulent heat fluxes along the coastal warming region from the new-generation atmosphere reanalysis data on a 25 km grid. These are common features to the past LMs and, furthermore, the region around the Kanto-Tokai districts becomes warmer than usual in warm seasons during the LM events. Our result reveals that the LM event can exert an influence upon the Japanese climate via the coastal air-sea interaction.

Mathematical models of stationary heat-exchange systems, differing in the organization of the fluid dynamics of the flows in them, are presented. Expressions for the thermodynamic perfection characteristics of the heat exchange in such a system (the heat load on the system, the entropy production in it, and its heat-transfer coefficient) and relations between them, depending on the fluid dynamics of the flows in the system, their organization, and the kinetics of heat transfer in the system, have been derived. It is shown that the kinetics of heat exchange in a heat-exchange system influences only the heat transfer in it.

Ground temperature (GT) variation significantly affects the energy performance of ground source heat pump (GSHP) systems. Both long-term thermal accumulation and short-term dynamic responses contribute to the degradation of the coefficient of performance (COP), especially under cooling-dominated conditions. This study develops a mechanism-based TRNSYS simulation that integrates building loads, subsurface heat transfer, and dynamic heat pump operation. A 20-year case study in Shanghai reveals long-term performance degradation driven by thermal boundary shifts. Results show that GT increases by over 12 °C during the simulation period, accompanied by a progressive increase in ΔT by approximately 0.20 K and a consistent decline in COP. A near-linear inverse relationship is observed, with COP decreasing by approximately 0.038 for every 1 °C increase in GT. In addition, ΔT is identified as a key intermediary linking subsurface thermal disturbance to efficiency loss. A multi-scale response framework is established to capture both annual degradation and daily operational shifts along the Load–GT–ΔT–COP pathway. This study provides a quantitative explanation of the thermal degradation process and offers theoretical guidance for performance forecasting, operational threshold design, and thermal regulation in GSHP systems.

Heat exchangers (HXs) have gained increasing attention due to the intensive demand of performance improving and energy saving for various equipment and machines. As a natural application, topology optimization has been involved in the structural design of HXs aiming at improving heat exchange performance (HXP) and meanwhile controlling pressure drop (PD). In this paper, a novel multiphysics-based topology optimization framework is developed to maximize the HXP for 2D cross-flow HXs, and concurrently limit the PD between the fluid inlet and outlet. In particular, an isogeometric analysis solver is developed to solve the coupled steady-state Navier–Stokes and heat convection–diffusion equations. Non-body-fitted control mesh is adopted instead of dynamically remeshing the design domain during the evolution of the boundary interface. The method of moving morphable voids is employed to represent and track boundary interface between the hot and the remaining regions. In addition, various constraints are incorporated to guarantee manufacturability of the optimized structures with respect to practical considerations in additive manufacturing, such as removing sharp corners, controlling channel perimeters, and minimizing overhangs. To implement the iterative optimization process, the method of moving asymptotes is employed. Numerical examples show that the HXP of the optimized structure is greatly improved compared with its corresponding initial design, and the PD between the fluid inlet and outlet is controlled concurrently. Moreover, a smooth boundary interface between the channel and the cold fluid, and improved manufacturability are simultaneously obtained for the optimized structures.