High-temperature heat pumps (HTHPs) are widely recognized as one of the most effective pathways for carbon emission reduction by recovering waste heat to improve energy utilization efficiency. However, systematic comparative analyses of heating performance improvements across different cycle configurations remain lacking, and optimal operation strategies for specific temperature ranges have not been clearly established. To evaluate the performance of HTHPs over a typical temperature range, this study constructed a versatile HTHP experimental platform capable of switching among four cycle configurations: single-stage cycle (SSC), gas-injection cycle (GIC), regenerative cycle (RC), and gas-injection regenerative cycle (GIRC). The heating performance of these cycles was experimentally compared. The results showed that GIC increased heating capacity by up to 20%, RC improved COP by nearly 20%, and GIRC achieved comprehensive improvements in both heating capacity and energy efficiency. Notably, under operating conditions of 50 degrees C evaporation temperature and 120 degrees C condensation temperature, GIRC achieved a remarkable increase in heating capacity of 57.74% and a COP improvement of 23.75% compared to SSC. Based on the analysis of heating capacity and operational efficiency, this study innovatively proposed an optimal cycle selection map for specific temperature ranges: GIC was found to more suitable for high condensation temperature conditions, RC performed best in "stepped" temperature intervals, and GIRC, despite its more complex structure and control, offered significant advantages in performance enhancement across the entire temperature range. These findings confirmed the critical role of cycle selection in improving the overall energy efficiency and provided important guidance for system design and performance optimization.

High-temperature heat pumps (HTHPs) are emerging as pivotal technologies for decarbonizing industrial heat supply by upgrading low-grade waste heat to meet diverse thermal demands. This review summarizes and analyzes the current state, applications and future trends of HTHPs from a carbon–neutral perspective. Core technological aspects—including cycle configurations, refrigerants, compressors, and integration strategies—are systematically analyzed. Thermodynamic comparisons reveal that cascade and coupled cycles can achieve temperature lifts above 100 °C under optimized conditions. The transition from high global warming potential (GWP) hydrofluorocarbons toward low-GWP hydrofluoroolefins, hydrochlorofluoroolefins, and natural refrigerants is accelerating. Large-capacity screw and centrifugal compressors are identified as key enablers for industrial-scale deployment. Typical industrial deployments of HTHPs across various fields are introduced, mainly structured around their application potential, integration characteristics, and implementation methods within energy-intensive sectors (e.g., paper manufacturing, textile dyeing). Future development will focus on high-power systems, advanced working fluid design, and digital control integration with renewable power and thermal storage. Collectively, HTHPs constitute an essential electrification pathway for achieving deep industrial decarbonization and carbon–neutral energy systems. • Reviews key HTHP technologies: cycles, refrigerants, compressors, and integration. • Compares thermodynamic and environmental performance of emerging refrigerants. • Quantifies energy-saving and CO2-reduction potentials in major industrial sectors. • Discusses coupling of HTHPs with renewables and thermal energy storage for net-zero heat supply.

In response to the problems of high ethylene glycol loss and high operating energy consumption in traditional MRU systems, a new MRU system was constructed using MVR technology. Taking the Panyu 34-1CEP platform as an example to solve parameters, the operating parameters were optimized with the goals of minimizing energy consumption and achieving optimal economy. The result shows that during the pre-treatment process, the optimal operating parameters are flash temperature of 70 degrees C, flash pressure of 0.2 bar, and reagent mass fraction ratio of 1:3. During the regeneration process, the optimal operating parameters are feed temperature of 80 degrees C, number of feed trays of 20, distillate feed ratio of 0.70, and reflux ratio of 0.23. During the desalination process, the optimal operating parameters are flash pressure of 0.2 bar, flash temperature of 130 degrees C, circulating heating temperature rise of 1 degrees C, circulation multiple of 10 times, and the circulating heater placed in the mixed stream. A comparison was made between the energy consumption and operating costs of the system, and it was found that the new system can save 56.01% of energy consumption and 61.68% of operating costs. Integrating MVR technology into offshore platforms has not been clearly used and explained in previous MRU system research literature.

To simplify the structure of accumulator and enhance the utilization of phase-change materials (PCM), this paper presents the development, experimental investigation, and life-cycle cost of a novel phase-change heat storage system with multi-pipe array type for greenhouse heating. The platforms of single accumulator performance evaluation and multi-pipe array storage system performance evaluation were established in the paper, and the life-cycle cost analysis was also studied in contrast to the PCM wallboard storage system and coal-fired heating system. It was found from the experimental investigation that the blackened coating treatment of PVC pipe could improve the thermal storage capacity by 66.7% compared to the original surface after 6 h of sun exposure. The preferred package size in multi-pipe array system was 75 mm in diameter under an illumination time of 6 h and long-lasting heat release (> 10 h), which not only guaranteed higher thermal storage capacity and transformation ratio but also maintained long-term heat discharge. The PCM loading capacity of 1560 kg can raise the night temperature by 1.6°C in the multi-pipe array storage system performance evaluation experiments under ambient temperature range of -18°C-+5°C. Due to its cost-effectiveness in terms of both system operation and initial investment, the life-cycle costs of the multi-pipe array system were USD1606, which was only 63.2 and 31.3% that of the wallboard system and coal-fired heater, respectively.

Supercooling harms inorganic hydrated salts, which are phase transition materials. Three variables were chosen for the experiment in order to better understand the variables influencing the supercooling of sodium decahydrate sulfate solution: stirring rate, purity of sodium decahydrate sulfate, constant temperature cooling of the water bath, and variable temperature cooling of the water bath. The quantity of heat exchange was kept constant by controlling the heat exchange temperature differential with variable temperature cooling. The controlled variable approach was used to examine how the three factors affected the supercooling of sodium sulfate decahydrate. The findings indicated that all three variables had an impact on the level of supercooling.The supercooling of the three materials under constant temperature cooling does not change appreciably as the stirring rate rises. The difference in supercooling under variable temperature cooling is around 7 degrees C. Constant temperature cooling always produces more supercooling than variable temperature cooling. The difference in supercooling between the two cooling techniques when the stirring rate is 0 r/min, 250 r/min, and 500 r/min is about 2 degrees C, 6 degrees C, and 9 degrees C.

Heat pump drying system is prospect technology with high efficiency and energy saving. Stable and efficient operation of heat pump drying systems in cold climate regions is achieved using a separate heat recovery room, which is designed to recover the heat in the exhaust air. Using a separate heat recovery room aims to maintain stable operation through switching between enclosed and partial air-loop modes. This paper analyzes the drying parameters to verify the stability of system, compares the running modes, and evaluate the economy of the dryer. It is found that setting a separate heat recovery room can achieve a higher material uniformity, and the air parameters are less affected by surroundings. Moreover, modes need to be adjusted according to the drying parameters and surroundings. Meanwhile, the proposed system has a great advantage in reducing the exergy loss of the heat exchanger, which can reduce operating costs.

This study develops a zero-emission heat pump system consists of heat pipes, water coils, and heat pumps for exhaust gas to mitigate the incomplete treatment, disgusting smell, and unrecoverable heat of exhaust gas after the drying process in the pharmaceutical industry. The quality of gas recycling and reuse is guaranteed by closed-loop dehumidification, waste gas treatment, and heating, thereby achieving near-zero emissions and recovery of waste heat. The experimental results of the system performance show that when the average temperature of the supply air is 65.1 °C, the relative humidity of the supply air is 21.1%, the air volumetric flow rate is 12 000 m3/h, the coefficient of performance of the heat pump unit is 4.7, and the specific moisture extraction rate of the system is 8.5 kg/(kW?h). The composition of the circulating gas shows that 73.2% of the volatile organic compounds are absorbed, and no non-condensable, flammable, or explosive gases are accumulated in the system during each production period.

This study proposed a multi-tube (polyvinyl chloride, PVC) array thermal energy storage structure based on butyl stearate phase change material, aiming to develop a simple and low-cost thermal energy storage device for solar greenhouses. The thermal environment of a greenhouse with a multi-tube array thermal energy storage device was studied through a series of experiments. The results indicated that the heat storage capacity of the device with a black surface was 66.7% higher than that with a white surface under similar irradiation conditions. Compared to devices with diameters of 50 mm and 110 mm, the discharging performance was the best when using a 75 mm PVC pipe containing butyl stearate. Moreover, in contrast to traditional solar greenhouses, the nighttime average temperature of the solar greenhouse with the multi-tube array thermal energy storage device was higher by more than 1.2 ℃, and the in-situ thermal energy storage capacity of the unit with butyl stearate reached 163 kJ/kg (including sensible heat). Therefore, multi-tube array thermal energy storage devices, which are economical, safe, and simple, can be widely applied in solar greenhouses.

For the development of practical products, valves such as orifice, double-inlet and multi-bypass in the pulse tube refrigerators, should be replaced by other more reliable structures. Potential choices are long thin tube, orifice or nozzle. In this paper, the difference between nozzle flow and orifice flow is analyzed. Their similarities are that they result in a similar reciprocal movement at hot end of the pulse tube; their differences are that their flow rates have different characteristics. According to state-flow theory, nozzle flow coefficient has a positive feedback to flow rate while orifice has no relation to flow rate generally. Further analysis shows this feature of nozzle will result in large refrigeration with the same pressure ratio and reservoir coefficient, which explains the reason that even lower temperature and a larger refrigeration amount can be obtained when symmetry-nozzle is used instead of orifice. Experiments of miniature pulse tube refrigerator show that symmetry-nozzle instead of check valves can improve the performance of pulse tube refrigerator effectively, which is also verified by calculation. But with Re number increasing, this advantage becomes unclear. This is explained both in analysis and in low frequency experiments.

In view of the problems of high energy consumption and heavy pollution in the drying process of large-scale multi-stage tower coal-fired corn in Northeast China, combined with the high cold characteristics of the regions, a multi-stage series dehumidification heat pump tower corn drying system was proposed, and a demonstration application project was established. The performance and life-cycle costs of the system were experimentally evaluated and compared to a traditional coal-fired corn drying tower. The results show that the system can achieve a supply air temperature above 68 degrees C under the ambient temperature of -20 degrees C. The total energy consumption of the system per hour is 595.5 kWh, and the specific moisture extraction rate reaches 3.39 kg/kWh. Moreover, the coefficient of performance of heat pump units reaches 3.0 - 6.3. Due to the attractive energy-saving potential, the operational cost-effectiveness of the multi-stage series dehumidification heat pump tower corn drying system can contribute to cut-down of life-cycle cost. It has been found that the life-cycle cost of the multi-stage series dehumidification heat pump tower corn drying system is 40.5% lower than that of the traditional coal-fired corn drying tower.

为减少太阳光、田间作业及雨水对苜蓿品质的影响,研发了一种植入式草捆热风干燥设备,并基于湿法收获的加工工艺,利用该系统对苜蓿草捆进行了热风干燥试验.结果表明,在热风温度90℃条件下,可实现在40 min内将草捆的含水率从27%降低到14%以内.在干燥过程中,该系统的热效率达90%;植入式干燥中,草捆内部热量由内而外均匀扩散,完成整个草捆的干燥.试验后,草捆内部大部分已经完全干燥,叶片保存完整且呈翠绿色;相比较自然晾晒后打捆的苜蓿,经植入式热风干燥后,苜蓿的粗蛋白和相对饲用价值分别增加了10.98%和19.72%.上述结果为湿法收获草捆的干燥加工提供参考和技术支持.

针对机床高刚度优化设计的共性技术问题,鉴于机床结构复杂和尺寸较大导致的数值迭代优化算法分析不足、优化加工试验成本较高的弊端,采用有限元模态分析和试验模态分析相结合的方法进行精密立式加工中心和龙门镗铣床的机床结构动态刚度优化设计.结果表明,在简化机床结构运动副的刚度阻尼等部件结合面的情况下,机床的有限元模态分析结果能够较好地揭示机床结构的动态特性,并结合试验模态分析结果,能够获取准确的模态参数;基于振型和模态参数,进一步指导机床结构的动刚度薄弱区,实现结构的优化设计,促进立式加工中心和龙门镗铣床低阶频率分别提升10％和40％以上,验证了优化分析方法在机床结构优化设计分析过程的良好适用性.

为优化甲醇催化燃烧加热的甲醇水蒸气重整制氢反应器性能,采用数值模拟的方法研究了反应器内耦合化学反应的传热传质过程,分析了进口流量、进料温度和水醇比对温度和反应性能的影响.结果表明:反应器温度分布受到吸放热反应的影响,并且由于热量不平衡而容易产生热点.进料温度对反应器温度影响较小,接近重整通道平均温度可以减小进口处温升.增加水醇比有利于提高甲醇转化率,但造成CO浓度轻微增加.当重整通道进口流量为2.0×10-7kg/s,燃烧通道进口流量为9×10-8kg/s,进料温度为543.15 K,水醇比1.3时,反应器内最大温差达到最小值为15.82 K,重整通道内平均温度为544.34 K,出口H2摩尔分数为0.63,CO摩尔分数为0.003 4.

Thermal coupling of endothermic and exothermic reactions is an important pathway for integrated thermal management within a methanol steam reforming reactor heated by methanol catalytic combustion. In this study, a numerical model is developed for heat and mass transfer calculations, methanol steam reforming and catalytic combustion reactions, which is used to explore the effects of design parameters on compact parallel channel reactor performance. Efficiency of the integrated reactor is optimized by the coupling of endothermic and exothermic reactions using conventional wall material. Temperature uniformity is improved by the adjustment of the flow arrangement and the catalyst distribution. This work provides an effective energy management strategy and tool which can be adopted in the design of portable hydrogen generation systems.

Condensation heat recovery is a way to save energy and reduce carbon emissions. For the auto-cascade refrigeration cycle system, increasing the heat recovery temperature is contradictory to ensuring the refrigerate performance of the system. Here is a nested cascade refrigeration cycle system with a heat recovery system is designed to increase the heat recovery temperature. Carry out energy, economy, and carbon emissions analysis of the system. In the economic analysis, the impact of carbon tax trading policies was considered. The analysis results show that when cooling 1 kgR23 consumes the same energy and obtains the same heat supply when the recovery temperature of the auto-cascade refrigeration cycle reaches 50C, the recovery temperature of the heat recovery system is 67C, which increases the recovery temperature by 17 C. Without considering carbon tax transactions, when the recovery temperature is lower than 100 C, the economy of the heat recovery system is better than that of standard coal; and when the recovery temperature is higher than 100 C, the economy of standard coal is better. When considering the impact of carbon tax transactions, when the heat recovery temperature is below 110 C, and the heat recovery system is the most economical. Among them, when the condensation temperature of R744 rises from 50 C to 120 C in the heat recovery system, the carbon dioxide emissions increase from 20.8 kg/GJ to 45.84 kg/GJ. In the temperature range of 50-120 C, it is lower than electric heating, standard coal heating, and natural gas heating.

为研究干燥温度及预处理方式对苜蓿(Medicago sativa)干燥特性及品质的影响规律,以绿色度、总色差、粗蛋白(CP)含量、相对饲用价值(RFV)及干燥速率作为指标,通过试验研究确定最优的苜蓿干燥工艺.以干燥温度和预处理方式作为试验变量,对苜蓿草进行热风干燥试验和色差分析,并对干燥后的苜蓿草进行品质检测.结果发现,干燥速率与干燥温度正相关,苜蓿品质与干燥温度负相关,苜蓿干草色泽优劣与干燥温度负相关;不同预处理方式下,压扁折弯处理对降低干燥周期的影响最显著,但对品质影响甚微.以品质和色泽作为评价指标,得出最佳干燥工艺为压扁折弯预处理及70～80 ℃的干燥温度.研究结果为苜蓿草的干燥加工提供了理论依据和技术参考.

针对变路径微创医疗机器人手术前端柔性精准穿刺的关键技术问题,采用嵌入式控制方法,突破柔性精准微创穿刺机器人的控制技术;主要通过上位机运动参数交互控制指令设置、摇杆控制指令输出、微控制器的串口指令接收和DMA大数据快速采集,进行控制信号的A/D精准转换和平均值滤波处理,并通过驱动器的细分和数字脉冲信号控制实现机器人所用步进电机的速度曲线逼近工程技术需求的S型加减速曲线,完成穿刺变路径、进针和旋转的多自由度方位主从操作精准控制.

为分析空晒对平板太阳能集热器热损的影响,通过准稳态的测试方法,得出3种涂层(蓝膜、黑铬、阳极氧化)集热器的热性能.此外,也分析了总热损系数随吸热板的平均温度、环温和风速等因素的变化趋势.分析结果表明,经过长期的空晒老化,蓝膜、黑铬和阳极氧化太阳能集热器的总热损系数分别为5.072、5.246和5.996 W/(m2·K),总热损系数的决定性因素为吸热板平均温度和发射率,风速和倾斜角是其重要影响因素,环境温度对总热损系数的影响较小.通过理论计算得出的总热损系数与实验数据拟合得出的系数相对误差不超过4％,说明所给出的不同涂层性能的计算结果具有较好的准确性.通过扫描电镜的观测分析,说明了在抗腐蚀、抗氧化和热稳定性方面,黑铬和阳极氧化涂层优于蓝膜涂层.避免平板太阳能集热器长期高温空晒,降低涂层发射率可有效减小集热器的总热损系数.

This review summarizes the theoretical conditions of making fluid ice from supercooled water, the ice making process, and two system forms of making ice from supercooled water. Theoretical conditions include thermodynamic principles and ice nucleus generation mechanism; the ice making process includes the preparation of supercooled water, the release of supercooled state, the separation of ice and water, and the storage of ice crystals; the system forms include direct cooling systems and indirect cooling systems. At the same time, the ice making rate per cycle of supercooled water, the influencing factors of ice blocking and the application scenarios of fluid ice are discussed. Finally, the advantages and disadvantages of making fluid ice from supercooled water are summarized, and future research is made.

针对超重力MVR热泵精馏模拟研究少的现状,对于乙醇-水这一典型非理想物系,基于Aspen Plus中重力场精馏塔非平衡级模型,通过编译和调用体积传质和相界面积参数Fortran子程序,构建了超重力精馏塔数学模型.在变回流比和进料位置两组工况下,进行了超重力MVR热泵精馏系统仿真模拟,将仿真结果与文献中实验结果进行了对比,发现塔顶产品质量分数xD的平均误差为0.74％,系统能效比COP的平均误差为9.52％,单位能耗蒸发量SMER的平均误差为13.26％,表明所建立的仿真模型具有较好的准确性,可用于超重力MVR热泵精馏系统仿真.以处理量为0.3 m3/h的超重力MVR热泵精馏系统为例,基于单一变量法,分析了运行参数对系统传质效果和能耗的影响,结果表明系统最佳回流比为6.8,最佳进料位置为第15块塔板,最佳转速为3000 r/min.