The air of high humidity and high sea spray aerosol (SSA) on islands or costal area always leads to the serious equipment corrosion and affects the living comfort of residents. Conventionally, the dehumidification and SSA reduction processes are separated and always consume precious electricity power and expendable materials. To simplified the procedure and reduce the energy consumption, this paper proposed a novel liquid‐ desiccant dehumidification system combined with sea spray aerosol removal. Based on the characteristics of liquid‐desiccant dehumidification and phase transitions of the ternary solution system, the combined system can be driven by the waste heat source of 70 oC. The proposed system was simulated by the thermodynamic equilibrium model and the optimization of design parameter are presented. The results showed that the humidity ratio of the supply air can be reduced by 8.24 g/kg(dry air). The COP of this novel system is around 0.446 and its exergy efficiency can reach 12.96%. Besides, the crystallization experiment is conducted to verify the feasibility of the NaCl separation process. This study provides a new method to simultaneously remove moisture and sea spray aerosol by using low‐ temperature waste heat.
Concentrated solar power (CSP) systems are acknowledged as a promising technology for solar energy utilisation. Supercritical CO2 (SCO2) cycle systems have emerged as an attractive option for power generation in CSP applications due to the favourable properties of CO2 as a working fluid. In order to further improve the overall performance of such systems, organic Rankine cycle (ORC) systems can be used in bottoming-cycle configuration to recover the residual heat. This paper presents a thermodynamic performance assessment of a combined SCO2/ORC system in a CSP application using parabolictrough collectors. The parametric analysis indicates that the heat transfer fluid (HTF) temperature at the inlet of the cold tank, and the corresponding HTF mass flow rate, have a significant influence on the overall system performance. The results suggest that the combined system can offer significant thermodynamic advantages at progressively lower temperatures. Annual simulationsfor a case study in Seville (Spain) show that, based on an installation area of 10,000 m2 , the proposed combined cycle system could deliver an annual net electricity output of 2,680 MWh when the HTF temperature at the cold tank inlet is set to 250 °C, which is 3% higher than that of a stand-alone CO2 cycle system under the same conditions. Taking the size of the thermal storage tanks into consideration, a lower HTF temperature at the cold tank inlet and a lower mass flow rate would be desirable, and the combined system offers up to 66% more power than the stand-alone version when the HTF inlet temperature is 100 °C.
Considered as promising candidates of composing eutectic chloride molten salts for high temperature energy storage and transfer, NaCl-KCl-CaCl2 and NaCl-CaCl2 systems are formulated into proper to satisfy the property requirement for heat storage and transfer. The thermal properties of the eutectic molten salts liquid such as melting points, specific heat capacity, density, viscosity and thermal stability were measured by DSC, Archimedes, rotation and mass loss curves under isothermal conditions methods. The results shown out, with appropriate operating temperature, lager heat capacity, acceptable viscosity and good thermal stability, NaCl-KCl-CaCl2 and NaCl-CaCl2 systems are the excellent high temperature heat storage and transfer materials under 850℃.
Energy is a complex system affected by multiple factors, accurate energy demand forecasts provide the basis for the formulation and implementation of energy planning. This paper builds a new model and predicts China’s energy consumption. This study drew three main conclusions. First, aco-integration test and Granger causality test can help users discover the relationships between China’s energy demand and its influencing factors. Second, the improved PSO-LSSVR model showed its superiority over other models in terms of forecasting energy demand, which further improved prediction accuracy. Third, the forecasting results indicate that China’s energy demand will peak in 2034, and that the peak is 6.7 billion tonnes of coal equivalent (tce). Based on the forecasting results, the paper offers suggestions related to China’s energy development policy.
STRACT Phase change material (PCM) emulsions have played increasingly important roles in many industrial fields as thermal energy storage media and heat transfer fluids. Precise size control of PCM emulsions is an important prerequisite for achieving consistent and repeatable performances. The present study introduced a novel co-flow microfluidic method to prepare uniform PCM emulsions in a controllable and reproducible manner. The droplet formation and size distribution of PCM emulsions were recorded in real time by a highspeed camera. The formation mode transition and droplet size variation were investigated by changing the flow rates of dispersed PCM and continuous water phases. The results showed that PCM emulsions with high uniformity and monodispersity can be attained in the squeezing and dripping modes, and the emulsion size increases with increasing flow rate of dispersed PCM and decreasing flow rate of continuous water. This study can provide technology support for future application of microfluidics in size-control of PCM emulsions.
The global energy Internet is one of the effective ways to solve the global energy crisis and environmental problems. The AC/DC hybrid power distribution network can accommodate a variety of new energy sources, providing conditions for the wide access of distributed power sources and new loads. The important development direction of the power grid form, and the wide-area interconnection of power systems with different voltage levels and different regional networks can be realized, which is the basis for building a global energy Internet. Based on the grid-connected characteristics of new energy sources, this paper proposes a design of AC/DC hybrid experimental system considering new energy access, studies the key equipment requirements of AC/DC hybrid test system, and designs the topology of each key device and its control strategy. Relying on the constructed AC/DC hybrid experimental system, this paper was verified.
Areas dealing with poor air quality may be significantly supported in their struggles, if district heating systems are established. Unfortunately, it is not always feasible to supply detached houses in comparatively remoted districts. Yet, all those buildings are usually connected to local electric grid, which may be easily upgraded. Thus, there is a real opportunity to use electric grid as a mean to reduce air pollution. Simultaneously, wind turbines present potential in providing electric energy with low CO2 footprint, what not always is a case if electricity is bought from national grid. This paper is to present a concept of heat receivers supplied in heat with electricity produced in dedicated wind farm and transferred via local electric grid. Simulation of needed system size and assessment of the potential for Kraków, Poland (Central Europe) is presented along with algorithm and analysis of system performance over typical meteorological year.
ESI is expected to create new interactions and interdependencies within the WES including power, gas, heat and transport. This makes existing evaluation frameworks incapable of assessing the performance of future integrated WESs, particularly due to multi-vector integration. Accordingly, this paper proposes an evaluation framework that addresses the gaps existing frameworks exhibit regarding the evaluation of such systems and capture their complexity. The framework starts with system analysis using a SoS approach to model the system under study in a way that facilitates its evaluation. This approach enables evaluation considering different system levels and multiple perspectives. The next step is MCA where appropriate evaluation criteria and a comprehensive set of indicators are derived and interpreted. These are related to system objectives and requirements and are linked to the different system components and functions. The framework could then be applied to case studies under various scenarios to realise trade-offs or synergies. This should serve as evidence for informing decision-making on the future system and the potential benefits of ESI.
Methanol to olefin (MTO) reaction is regarded as an important bridge between traditional coal and modern petrochemical industry. Its importance poses significant challenges at the same time in terms of complexity. Many works have been made to effectively represent the mechanism and expand its application. A new kinetic model is proposed for the methanol-to-olefins (MTO) reaction in this paper. The MTO reaction kinetics is investigated by way of a lumped kinetic model based on certain assumptions. The kinetic parameters were determined by using some experimental data treated by genetic algorithm. In the proposed model, the deactivation constant a is the only intrinsic parameter required to represent the effect of catalyst deactivation on the conversion and product yields. This approach is shown to be effective for modeling complex deactivation kinetics in MTO. The proposed model gives a reasonable representation of the experimental data.
While energy systems become more and more complex mathematical optimization can be used to generate good operating strategies for power generators and consumers. In order to reduce the complexity and thus the computing time for solving the Unit Commitment Problem several approaches for abstracting the original problem are introduced in literature. This paper focuses on a theory for the information theoretical evaluation of aggregation approaches in operating strategy optimization of energy systems. The theory is validated via two aggregation approaches, which aim at reducing computing time for solving the optimization problem, while maintaining the solution quality of the original problem.