The problem of inconsistency between the measurement results of the cooling capacity of room air conditioners between environmental chambers still plagues China′s air-conditioning industry and is a meteorological problem that easily leads to conflicts in international trade. A standard cold-source device that can calibrate laboratory measurement results of the enthalpy difference needs to be urgently studied. In this study, a standard cold-source device based on ice slurry refrigeration is proposed, including an ice slurry preparation system and a heat exchange system, based on a study of several mainstream cooling capacity measurement methods for room air conditioners and the research status of standard cold-sources at home and abroad, combined with an in-depth understanding of the physical process of ice slurry refrigeration. Experimental research and refrigeration capacity uncertainty analysis are conducted to verify whether the standard cold-source device could calibrate the enthalpy difference laboratory. The experimental results show that the relative uncertainty of the measured cooling capacity of the standard cold-source device in the enthalpy difference chamber can reach 1.2% when setting 0 ℃ on the ambient side and setting the standard cooling condition on the room side with mass flow rate of 70 g/s, which is approximately 1/3 of the air enthalpy method and can be used as a standard cold source to calibrate the cooling capacity measurement results of the enthalpy difference chamber, which can help improve the international competitiveness of the refrigeration industry.

Room-temperature magnetic heat pumps, one of the main applications of the magnetocaloric effect near room temperature, offer high efficiency, environmental protection, low noise, and low vibrations. This study discusses the application potential of a cascade magnetic heat pump cycle with a large temperature span by comparing the theoretical magnetic heat pump and refrigeration cycles. The results show that meeting the kilowatt-level heating capacity and achieving a wide temperature span of approximately 30 K in an actual heating scenario poses challenges to room-temperature magnetic heat pumps. The differences in design and application between the room-temperature magnetic heat pump and the existing room-temperature magnetic refrigeration prototypes are discussed, with a focus on magnetocaloric material selection strategies and performance evaluation indices suited for large temperature spans. The comparative analysis of magnetic heat pumps and magnetic refrigeration in this study also helps researchers to clarify the key to the design and application of large temperature span magnetic heat pumps based on existing research on room-temperature magnetic refrigeration. It promotes the comprehension and application of room-temperature magnetic heat pumps.

To address the limitations of magnetic refrigeration and magnetic heat pump systems near room temperature, this study establishes a one-dimensional numerical model of a cascade active magnetic regenerator and examines the key parameters influencing heating performance. The simulation results indicate that a higher flow rate of the heat transfer fluid accelerates the attainment of a steady-state temperature at the hot end. Furthermore, as the flow rate increases, the no-load temperature span initially increases and then decreases, while the heating capacity increases. Reducing the (de) magnetization time and flow time can significantly enhance both the heating capacity and no-load temperature span, achieving values of up to 55.2 W and 29.9 K, respectively, under a 1-1-1-1 s operating sequence. When the Curie temperature interval of LaFeSiH increases, the no-load temperature span first increases and then decreases, reaching a maximum of 40.2 K at a Curie temperature interval of 6 K. Among the four filling length ratios, the optimal heating performance is achieved at a ratio of 2∶2∶2∶2∶7, resulting in a maximum no-load temperature span of 31.2 K and a maximum heating capacity of 64 W.

An electric vertical take-off and landing flying vehicle (eVTOL) is a potential technology for future urban air mobility. A major challenge for thermal management systems is the high cooling requirement and the variable application scenarios. To overcome this challenge, a multi-scene eVTOL-integrated thermal management system was developed. In this study, an eVTOL thermal management simulation platform based on Amesim simulation software was developed to investigate the effects of flight conditions on thermal management and range. The simulation results show that increasing the cruise altitude can reduce the thermal management energy consumption when the ground temperature is high. The maximum reduction of energy consumption for thermal management energy is 4 kW when the cruising temperature ranges from 10 ℃ to 26 ℃. When the hovering rescue duration is more than 150 s during the emergency rescue operation, the temperature difference inside the battery becomes too pronounced. A reduced payload improves the range, with the unloaded range being 1.33 times greater than the fully loaded range.