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Moisture-based adsorption thermal battery (ATB) holds great potential for addressing energy storage and utilization challenges. In this work, a proof-of-concept solar harvesting building envelope using the Trombe-wall (T-wall) based ATB design is proposed and investigated, featuring a developed composite sorbent as the porous wall for effective heat storage and utilization. To demonstrate the feasibility of employing the ATB-based building envelope for day-and-night space heating, a 3-dimensional simulation model of the ATB wall is meticulously designed and comprehensively studied. Parametric analyses of various working conditions, including examining the effects of solar radiation intensity, air temperature, air humidity, and airflow velocity on the heat charging and discharging performances of the ATB wall, are conducted using the numerical model. Simulation results indicate that, under a solar irradiance level of 700 W m−2 during the daytime, an average output air temperature of 42.4 °C and an average heating power density of 2.5 kW m−3 are achieved. Extending the heat charging time to 8 h and 12 h significantly improves the desorption efficiency, which is able to reach 47.2% and 75.0%, respectively. In terms of heat discharging performances, various working conditions investigated in the ATB wall model will lead to different thermal output performances. • A building envelope concept of solar ATB wall is proposed to realize continuous space heating and low energy consumption. • A 3-dimensional simulation model of the solar ATB wall is investigated for parametric analysis and performance prediction. • The effects of solar radiation, air temperature, humidity and flow rate on the heating performance of the model are examined. [ABSTRACT FROM AUTHOR]

Abstract A quasi-isostatic pressing technique for encapsulating spherical high-temperature inorganic phase change materials (PCMs) was presented in this work. To enhance the thermal conductivity of PCMs, graphite powder was dispersed into the PCM pellets. Meanwhile, cellulose particles, as sacrificial particles, were mixed with the PCM pellets to relieve the volumetric expansion of the PCMs during the phase change process. The effects of the latent heat, thermal conductivity, and thermal expansion behavior of the PCM/graphite capsule were investigated. The PCM capsules were able to work at temperatures up to 900 °C, including undergoing a solid-liquid phase change at 803 °C with a latent heat of 159.6 J g−1, and survived more than 300 thermal cycles as thermal energy storage devices. The thermal performance of the PCM capsules between 500 and 900 °C was numerically investigated using a modified one-dimensional (1-D) enthalpy-based model. The results indicated that the average heat transfer of the PCM capsules with graphite-dispersed core was significantly elevated during both the charging (by 92.5% for 99% charge) and discharging (by 168.4% for 99% discharge) processes, compared to the pure core PCMs. Highlights • Encapsulation of high-temperature inorganic phase change materials using graphite as heat transfer enhancer was presented. • The PCM capsules had a solid-liquid phase change at 803 °C (159.6 J g−1) and could survive more than 300 thermal cycles. • The numerical results showed that the PCM/graphite performed a significantly enhanced average heat transfer. [ABSTRACT FROM AUTHOR]

Water-based adsorption thermal battery (ATB) could provide huge possibility in widespread applications; especially for space heating, leading to appreciable energy saving and low-grade heat energy utilization. A proof-of-concept prototype based on composite adsorbents has been constructed to investigate the thermal performances of a packed-bed ATB. A possible strategy of tunning airflow rate for performance regulation is proposed and studied to realize stable thermal output. Additional experimental results indicated that the output temperature and heating power can be synchronously stabilized through progressive tunability of loop airflow rate in the loop-cycle ATB system. The output RH spans 40–60% along the effective discharging process, enabling a controllable humidity management in the application of direct space heating considering human thermal comfort. A three-dimensional computational model for predicting the overall thermal output performances of a packed-bed adsorption thermal battery is further developed and established. The simulation results reveal that an effective heating time of 8.6 h with a discharging threshold temperature of 24 °C, and an average power density of 19.3 kW m−3 can be achieved with a maximum heat discharging efficiency of 63.4%. It is, therefore, apparent that the ATB is capable of achieving stable thermal outputs for space heating applications. • An experimental and numerical parametric study analysis for the packed-bed adsorption thermal battery is conducted. • A strategy of tunning airflow rate for stable output performance is proposed and developed for adsorption thermal battery. • The proposed modelling and optimization method can be employed to analyze and predict overall thermal output performances. • Different combinations of open-cycle and loop-cycle modes in adsorption thermal battery can meet various heating demands. [ABSTRACT FROM AUTHOR]

Thermal energy storage is highlighted as a crucial strategy for energy saving and utilization, in which domain, latent heat storage using phase change materials has gained great potential for efficient heat storage and thermal management applications. A strategy for developing high energy-storage-density and power-density latent heat storage units, through the compression-induced assembly of expanded graphite based stearic acid composites and the macro encapsulation method by using polyethylene shells, is demonstrated. The fabricated composite shows a satisfactory phase change enthalpy of 161.24 ± 0.5 J g−1, and enhances thermal conductivity to 13.4 ± 0.8 W m−1 K−1. The resulting heat storage unit also exhibits form-stable, leakage-proof, good homogeneity, and high-power-density behaviors. A 0.462 kWh proof-of-concept prototype of the packed-bed latent-heat-storage system by using 492 heat storage units has demonstrated its feasibility in fast heat charging/discharging operations. The outlet air temperature in the discharging process can maintain above 30 °C for over 1.74 h with a heat storage utilization efficiency of 90.3 ± 6.1% and an effective discharging efficiency of 93.5 ± 9.4%, under a volumetric flow rate of 30 m3 h−1 and heat storage temperature of 27–86 °C. The maximum and average power density, and effective energy density are obtained as 20.7 ± 1.6 kW m−3, 14.2 ± 0.9 kW m−3, 24.8 ± 2.5 kWh m−3, respectively, with a discharging threshold temperature of 30 °C. This high-power-density apparatus using form-stable heat storage units has realized hourly rapid heat charging-discharging processes, showing its prospective potential of low-temperature heat storage and thermal management. • A compression-induced assembly and macro encapsulation method is developed to prepare phase-change heat storage units. • The fabricated EG-SA composite exhibits a satisfactory phase change enthalpy and enhanced thermal conductivity. • The resulting heat storage units show form-stable, leakage-proof, good homogeneity, and high-power-density behaviors. • A packed-bed latent-heat-storage prototype is demonstrated to realize hourly rapid heat charging and discharging processes. [ABSTRACT FROM AUTHOR]

Thermocline storage in a packed-bed is considered as a promising thermal energy storage (TES) method that achieves cost reduction with respect to current concentrated solar power (CSP) plants. Several parametric studies investigated thermal performances of different types of packed-bed thermocline TES systems, and cost analyses and dimension design studies were conducted based on this. However, parametric studies typically involve high computing costs for a dimension design, and results obtained by correlation fitting suffer from a relative lack of accuracy. The main objective of the present study involves directly determining the tank size of a packed-bed thermocline TES system to satisfy certain design requirements of a CSP plant without requiring parametric studies. In order to achieve this goal, a one-dimensional enthalpy-based dispersion-concentric (D-C) model is developed and validated to investigate the periodic thermal behavior of the system. An efficient tank size estimation strategy is proposed based on the periodic thermal performance of the system. The strategy is used to size four different packed-bed thermocline TES types under two exemplary operating conditions. The results reveal that tank size estimation strategy is independent of initial conditions, and that it is self-convergent, involves cost saving in terms of computing costs, is generally applicable, and can provide guidelines for the design of a TES system for CSP plants. [ABSTRACT FROM AUTHOR]

The scaling of bulk Si-based transistors has reached its limits, while novel architectures such as FinFETs and GAAFETs face challenges in sub-10 nm nodes due to complex fabrication processes and severe drain-induced barrier lowering (DIBL) effects. An effective strategy to avoid short-channel effects (SCEs) is the integration of low-dimensional materials into novel device architectures, leveraging the coupling between multiple gates to achieve efficient electrostatic control of the channel. We employed TCAD simulations to model multi-gate FETs based on various dimensional systems and comprehensively investigated electric fields, potentials, current densities, and electron densities within the devices. Through continuous parameter scaling and extracting the sub-threshold swing (SS) and DIBL from the electrical outputs, we offered optimal MoS2 layer numbers and single-walled carbon nanotube (SWCNT) diameters, as well as designed structures for multi-gate FETs based on monolayer MoS2, identifying dual-gate transistors as suitable for high-speed switching applications. Comparing the switching performance of two device types at the same node revealed CNT's advantages as a channel material in mitigating SCEs at sub-3 nm nodes. We validated the performance enhancement of 2D materials in the novel device architecture and reduced the complexity of the related experimental processes. Consequently, our research provides crucial insights for designing next-generation high-performance transistors based on low-dimensional materials at the scaling limit. [ABSTRACT FROM AUTHOR]

[Display omitted] • Lightweight and stretchable graphene armor for EMI shielding and strain sensing. • Sandwich architecture is designed to enhance EMI shielding performance and strain sensing sensitivity of the graphene armor. • The laminated graphene film is fabricated by laser induction in a single step under an ambient atmosphere. • The sandwich graphene armor exhibits an EMI SE up to 69.8 dB at an ultralow density of 0.228 g/cm3. • The gauge factor of the graphene armor can reach 258 at a strain range up to 100%. Lightweight and stretchable electromagnetic interference (EMI) shielding materials are desirable for wearable electronics. Herein, a graphene armor composed of laminated graphene film (LGF) and hierarchical porous graphene foam (HGF) with film/foam/film sandwich architecture is reported for human EMI shielding and motion monitoring. The LGF with micron-level interlayer spacing (∼2 μm) is fabricated by laser induction in a single step under an ambient atmosphere. Attributed to abundant interfaces and excellent electrical conductivity of 1670 S/m, the LGF exhibits an EMI shielding effectiveness (SE) up to 36.3 dB at a thickness of 19.4 μm. Due to the three-dimensional porous foam structure with the tunability of graphene content, the EMI SE of the HGF can range from 10 to 80 dB. Based on HGF with a graphene content of 27 wt%, the sandwich graphene armor with a thickness of about 2 mm exhibits an EMI SE up to 69.8 dB at an ultralow density of 0.228 g/cm3. Furthermore, the graphene armor possesses excellent mechanical properties as strain sensors that the gauge factor can reach 258 at the strain range up to 100%, thus the graphene armor can be used for motion monitoring while protecting the joints of the human body. The results demonstrate that sandwich architecture can not only enhance the EMI shielding performance of foam materials but also be an effective approach to improving the sensitivity of strain sensors. Therefore, the highly stretchable, conformal, and lightweight sandwich graphene armor is promising for multifunctional applications of EMI shielding and strain sensing. [ABSTRACT FROM AUTHOR]