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Summary Heat storage technology can enrich and store dispersed and discontinuous heat and significantly improve energy efficiency. This paper reports a pilot‐scale sensible heat storage unit, which uses circular channel solid made of castables as the heat storage bodies and heat transfer oil as the working fluid. When performing, the heat transfer oil passes through the flow channel of the heat storage body and is in direct contact with the heat storage body for heat exchange. The experiment explores the unit's thermal performance, including heat, power, and charge energy efficiency under different charging temperature difference modes. At the same time, the normalized charge energy efficiency is used to evaluate the heat‐storage unit's heat absorption capacity during the charging process. The results show that the average heat storage capacity of the heat storage body is about 1.10 × 106 kJ, accounting for 89% of the heat storage capacity of the unit, and the remaining 11% is the heat stored in the oil inside the unit. In addition, the charging mode with step temperature rise used in the experiment can make the heat stored by the regenerator increase linearly with time. The charging mode with a more considerable temperature difference can significantly enhance the charging power and shorten the charging time, but the increase in the temperature difference reduces the efficiency of the charging process. The efficiency in the experimental range is reduced from 64.5% in the minimum temperature difference mode to 34.8% in the maximum temperature difference mode. This paper has a certain supplementary function for the design and application of heat storage and the evaluation of the thermal performance of the heat storage unit.

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Revealing the mechanism of exciton energy transfer (EET) in the emitting layer (EML) of organic light-emitting devices is significant for improving the device performance. In this paper, we explore how the host-TADF combinations influence EET in the amorphous film, especially for the Dexter energy transfer (DET) process. With the help of density functional theory calculations and molecular dynamics simulations, we study the Förster resonance energy transfer and the DET of two thin films (2,6-2CzBN:4tCzBN and 3,5-2CzBN:4tCzBN) to determine how the intermolecular interaction influences the energy transfer. We find that the exciton coupling value is the decisive factor that leads to the external quantum efficiency difference between the two amorphous films by analyzing the variable in Marcus theory. The molecular spatial arrangement in 3,5-2CzBN is beneficial to enhance exciton coupling. The more space around benzonitriles helps to strengthen fragment interaction between benzonitriles, which plays a vital role in exciton coupling and spatial distribution. This work reveals how the molecular spatial arrangement and interaction influence energy transfer.