Equipment failures, weather conditions and other factors can lead to a large amount of abnormal data in distributed photovoltaic (PV) power generation systems, causing serious effects on their safe and stable operation. In order to accurately identify and remove these abnormal data, a distributed PV power generation abnormal data identification method is proposed based on dynamic time warping (DTW) and two-stage quartile. Firstly, continuous abnormal data identification and elimination are achieved by comparing the mean photovoltaic power under similar irradiance. Abnormal data are eliminated based on the comparison of the mean photovoltaic power at the same period, taking into account the fluctuation of the photovoltaic power generation curve. A comprehensive curve similarity judgment method based on DTW and Euclidean distance is used to consider the fluctuation characteristics of the data more comprehensively, thereby improving the recognition and elimination effect of continuous abnormal data. Secondly, the DTW-Two-Stage Quartile abnormal data identification algorithm is proposed, and the first-order change rate and the second-order change rate are used to eliminate discrete abnormal data from the fused data, effectively identifying and eliminating discrete abnormal data. Finally, it is determined whether a fault has occurred based on the results of abnormal data identification and elimination. Experimental results show that, after the proposed algorithm eliminates abnormal data, it can better fit the distribution of normal photovoltaic power data. Compared with the quartile method and the 3-Sigma algorithm, the linear correlation degree of the proposed algorithm before and after the elimination of abnormal data has increased by 58.15% and 68.41% respectively, with better identification results.

Partial heating supercritical carbon dioxide (S-CO₂) power cycle system is proven to be one promising option for waste heat recovery. By using LiBr-H₂O and NH₃-H₂O as working fluids, two types of novel combined power systems consisting of a parting pre-heating S-CO₂ cycle and different absorption power cycle (APC) systems are proposed. The detailed mathematical models of the proposed parting heating S-CO₂/APC systems are built and verified. Based on the results of single- and multi-objective optimization, the performances of the proposed S-CO₂/APC system and the standalone S-CO₂ system are compared from the perspective of thermodynamics and economics. The single-objective optimization study reveals that the net power output and net efficiency of the S-CO₂/LiBr-H₂O system and the S-CO₂/NH₃-H₂O system increases by 7.40% and 4.30%, respectively, compared with the standalone S-CO₂ system. The multi-objective optimization results show that, the S-CO₂/LiBr-H₂O system and S-CO₂/NH₃-H₂O system can obtain improvements of 7.94% and 5.13% in net efficiency as well as promotion of 12.35% and 9.02% in the specific investment cost respectively, indicating that the S-CO₂/LiBr-H₂O system has a greater potential. Exergy loss analysis reveals that the main exergy loss exists in the coolers and the heaters, and the proposed S-CO₂/APC systems can significantly reduce the exergy loss in the S-CO₂ cooler by about 45%.

In order to investigate the effects of oxygen addition amount and type of gasification medium on coal gasification efficiency as well as the optimization of integrated gasification combined cycle (IGCC) power system, a simulation analysis is carried out by baking two kinds of coals with significant differences in oxygen content as the examples. Firstly, based on the equilibrium reaction model, the influence of oxygen carbonation stoichiometric ratios (considering the oxygen content of different coal types) on gasification characteristics for different coal types is compared. Then, the gasification characteristics are analyzed and optimized when CO₂ and steam are added as gasification media respectively. On this basis and considering CO₂ capture, a novel IGCC power cycle system with CO₂-assisted gasification, pure oxygen combustion and partial gas recirculation is proposed and analyzed, and the gas turbine model is simulated and optimized. The results show that, the coal gasification performance is the best when the total oxygen-carbonation stoichiometric ratio is around 0.47. Under this condition, adding CO₂ as the gasification medium can increase the efficiency of cold gas by about 1.3%, compared with that of the conventional way that adding steam as the gasification medium. Compared with the conventional IGCC power system with pre-combustion decarbonization, the net power efficiency of the proposed system increases by about 1.5% and the exergy efficiency increases by 1.7%, which provides a new idea for designing a low-carbon and efficient IGCC power generation system.

To achieve the carbon peak and neutrality targets, facilitate low-cost disposal of industrial solid wastes (namely semi-coke ash), and develop new green and low-carbon composite materials, carrying out carbon capture using semi-coke ash is proposed, based on the existing semi-coke ash/sodium nitrate composite phase change heat storage materials. The performance of semi-coke ash and composite phase change heat storage materials before and after carbon sequestration is studied. The results indicate that, the optimal conditions for carbon sequestration in semi-coke ash are: gas composition of 20%CO₂/80%N₂, ventilation time of 40 minutes, and heating temperature of 650 ℃. Under the optimal experimental conditions, the carbon sequestration rate of semi-coke ash reaches 29.27%. The optimal mass ratio of the resulting composite phase change heat storage material, namely the carbon-sequestered semi-coke ash to NaNO₃ is 5:5. It achieves a heat storage density of 288.65 J/g at 100~380 ℃, with better mechanical properties, thermal stability, and chemical compatibility. The use of carbon-sequestered semi-coke ash as a skeletal material to prepare composite phase change heat storage materials is highly feasible, providing a new approach for the resource utilization and carbon emission treatment of industrial solid wastes, namely semi-coke ash.

The excessively high temperature gradient inside solid oxide fuel cell (SOFC) can lead to failure of the cell, so it is critical to reduce the temperature gradient in the SOFC and enhance the uniformity of the cell temperature. By combining with the electrical, thermal, flow, and mass transfer physical fields, a multi-physics field coupling model of the SOFC is established. The accuracy of the model is verified by comparing with the experimental data. The SOFC temperature and temperature gradient distributions are investigated by the SOFC model and the maximum temperature gradient in the cell reaction zone is determined as the optimization objective. The obstacle structure in flow channel is designed, and the effectiveness is proved. The shape, height and width of the obstacle structure are discussed and analyzed. It is found that the obstacle affects the maximum temperature gradient in the reaction zone mainly by changing the fluid flow rate and the oxygen molar concentration in the reaction layer. The change of the obstacle for the pressure drop in the flow path mainly affects the power density loss. Finally, the circular obstacle (h=0.8 mm, d₁=4.0 mm) is identified as the optimal structure. With the same net power density as the conventional channel, the maximum temperature gradient is 43.35 K/cm, which is 9.4% lower than that of the conventional channel.

Energy saving and emission reduction in road transport field is an important part of the strategy to achieve carbon neutrality. Heavy commercial vehicles have high power and range requirements, and the transition from conventional internal combustion locomotives to hybrids with waste heat recovery is of great significance in improving engine efficiency and reducing energy consumption. However, the waste heat recovery system integrated with hybrid power in current research mostly adopts a simple layout, and only recovers a single form of waste heat energy from the cylinder liner water or flue gas, which has a limited degree of enhancement to the overall efficiency of the vehicle. Therefore, a waste heat recovery system based on the organic Rankine cycle that can simultaneously recover the waste heat from flue gas and cylinder liner water and operate efficiently under full operating conditions is proposed. The system is coupled with a series hybrid power system and operates under high-speed and suburban road conditions, the performance of the organic Rankine cycle system and the improvement effect of the overall energy efficiency of the integrated system are then investigated. The results show that, under the premise of considering the weight of the waste heat recovery system, the waste heat recovery system improves the engine efficiency by 2.85% and reduces the overall fuel consumption by 6.78% under high-speed USHWY conditions. Under urban road UDDS conditions, it enhances the engine efficiency by 2.30% and decreases the overall fuel consumption by 6.43%. The above results demonstrate the system’s fuel-saving capability and application potential. It is found that the organic Rankine cycle system has a large inertia, and the long-term stable operation of the engine plays a decisive role in improving the output power and efficiency of the system, so the system is suitable for matching with high-speed operation of heavy-duty hybrid vehicles.

The utilization hours of thermal power units continue to decline, and peak shavings become more frequent. Under this background, the existing ammonia injection mixing technology can no longer meet the new normal needs of coal-fired power plants, and ultra-low emissions put forward higher requirements for uniformity of the NH₃/NO_x molar ratio distribution at the SCR reactor inlet. The grid-type ammonia injection grid (AIG) and static mixer are optimized through CFD numerical simulation and physical model test. The design method and an anti-blocking nozzle are proposed to ensure the uniformity of ammonia distribution, adjustment flexibility, and anti-blocking performance of the ammonia injection grid. Moreover, a triangular large-scale flue gas self-mixing device is developed to improve the uniformity of the NO_x concentration field at inlet of the SCR reactor and enhance the load adaptability of the SCR denitrification device from the root. The relative standard deviation of NO_x distribution at the SCR outlet of a 600 MW unit under high, medium and low loads reached 8%~19% by using this technology, and the ammonia escape at full load decreased by 51%.

The effects of blending ratio and heating rate on co-combustion characteristics of municipal sludge and camellia oleifera shell were studied by thermogravimetric analysis, and the combustion kinetics of the samples were modeled by two methods, Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS). Moreover, the flammability index and comprehensive combustion characteristic index of various samples were calculated, and the interaction between the mixed fuel components during the combustion process was analyzed. The results show that, the burnout temperature of the mixed fuel significantly reduced, and the combustion stability and comprehensive combustion characteristics were significantly improved after the sludge was mixed with camellia oleifera shell. With the increase of the mass blending ratio of camellia oleifera shell from 20% to 80%, the burnout temperature decreased from 590 ℃ to 532 ℃, the burnout degree gradually increased, the mass loss increased from 63.13% to 92.19%, and the flammability index and comprehensive combustion characteristic index increased by 1.66 and 2.32 times, respectively. The interaction between the components of sludge and camellia oleifera shell mixed combustion occurred, which showed an inhibition effect in the volatile combustion stage, while a promoting effect in the fixed carbon combustion stage. The average apparent activation energies of sludge calculated by the FWO method and KAS method were 122.32 kJ/mol and 118.08 kJ/mol, respectively, and the average apparent activation energies of the camellia oleifera shell were 166.46 kJ/mol and 164.94 kJ/mol, respectively. The average apparent activation energy of the mixed samples increased with the mass mixing ratio of camellia oleifera shell.

In the system realizing waste heat utilization through thermal cycle, there is a mutual restriction relationship between the cycle thermal efficiency and the utilization rate of heat source, solving this problem is the key to build an efficient waste heat utilization system. Taking supercritical carbon dioxide cycle as an example, this paper constructs a new cycle, namely the partial expansion cycle, to broaden the waste heat absorption temperature range, so as to enhance the waste heat utilization rate. After coupling gas turbine exhaust, the waste heat utilization system’s power generation efficiency reaches 28.62%, the cycle thermal efficiency reaches 34.03%, and the heat source utilization rate reaches 84.11%. Moreover, to demonstrate the advantages of the partial expansion cycle, a waste heat utilization system is constructed based on the single regenerative Brayton cycle and the recompressed Brayton cycle. Furthermore, the three cycles are compared. Through calculation using the first and second law of thermodynamics, it is found that the power generation efficiency of the partial expansion cycle is higher than that of the other two classical cycles. Via analyzing the circulation process, it is found that the reason for the high efficiency of the partial expansion cycle is that the partial expansion structure broadens the endotherm temperature zone, makes the heat source utilization rate increase greatly, and thus improves the power generation efficiency.

By taking the test bench of a micro gas turbine cycle system as the research object, a mathematical model for regenerative cycle system of the micro gas turbine is established. On this basis, the performance prediction and analysis for the regenerative cycle system is carried out. Considering the performance parameters of the system’s key components are presently unknown, the maximum likelihood estimation method is employed to estimate them by using the experimental data. The results show that, the error between the model predicted value and the experimental value is smaller than 3%, indicating the model can accurately predict the thermal performance of the cycle. Subsequently, based on the established model, a performance simulation of the recuperative cycle is conducted under various working conditions. The variation rules of power, generation efficiency, exhaust gas energy, and exhaust gas temperature with the changes of load and ambient temperature are obtained, and the compressor’s operating range is also obtained. The information regarding the key components of the microturbine and the performance characteristics acquired through this study can serve as valuable references for related research.