Energy Conversion and Management最新文献_第7页

Energy, exergy, economic, and environmental (4E) assessment of an experimental moderately-high-temperature heat pump for district heating and cooling networks

IF 9.9 1区工程技术 Q1 ENERGY & FUELS

Energy Conversion and Management

Pub Date : 2025-02-01 DOI: 10.1016/j.enconman.2024.119346

Ghad Alarnaot-Alarnaout, Joaquín Navarro-Esbrí, Ángel Barragán-Cervera, Adrián Mota-Babiloni

Developing district heating and cooling networks (DHCNs) requires new heat pumps (HPs) technologies to improve energy efficiency and replace fossil fuel boilers. This study presents a novel R-1234ze(E) moderately-high-temperature HP integrated with a semi-hermetic reciprocating compressor and an internal heat exchanger (IHX) controlled by a solenoid bypass valve. The HP is evaluated in terms of energy, exergy, carbon footprint, and economic viability. Two main configurations are explored: (i) simultaneous heating and cooling for 4G (4th generation) district heating networks (DHNs) and district cooling networks (DCNs), and (ii) heat source from a 4G or 5G DHN to increase the evaporation temperature, reaching a maximum value of 48 °C at 85 °C condensing temperature (48 °C/85 °C). Six scenarios combine several evaporating and condensing temperatures, with and without the IHX. The experimental results show that the IHX improves the heating capacity from 4.8 % to 19.3 %. However, it has a limited effect on simultaneous heating and cooling efficiency. Scenarios 2 °C/45 °C and 30 °C/65 °C with IHX achieve the highest COP (4.31 and 4.92). Exergy analysis reveals more significant destruction in extreme operating conditions, varying the efficiency from 21.5 % (low suction temperature) to 10.5 % (high suction temperature), highlighting improvement possibilities mostly in the evaporator, compressor, and condenser. Heat source DHN scenarios involve higher equivalent CO₂ emissions per MWh, especially when the condensing temperature is higher. Economic analysis proves viability for simultaneous heating and cooling in all scenarios, with an optimum payback period of 1.96 years. It occurs similarly for heat source DHN in selected cases (30 °C/65 °C, 30 °C/80 °C with IHX, and 48 °C/85 °C without IHX), with an optimum payback period of 3 years.

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引用次数: 0

Innovations in improving photovoltaic efficiency: A review of performance enhancement techniques

IF 9.9 1区工程技术 Q1 ENERGY & FUELS

Energy Conversion and Management

Pub Date : 2025-02-01 DOI: 10.1016/j.enconman.2025.119589

Moataz M. Abdel-Aziz, Asmaa A. ElBahloul

The growing demand for clean energy, driven by environmental concerns, has brought renewable energy technologies, particularly photovoltaic (PV) systems, to the forefront of sustainable energy generation. PV technology harnesses solar energy, a virtually unlimited resource, to meet global electricity needs. Despite the advantages of PV systems such as ease of installation, low maintenance costs, and rapid growth efficiency remains a critical factor in maximizing energy output. This review paper presents a comprehensive analysis of state-of-the-art innovations in PV efficiency enhancement techniques, including cooling methods, mobile PV systems, integrated PV systems, material innovations, and optimization strategies. By examining the influence of environmental factors such as panel temperature, dust accumulation, and shading, the paper identifies key challenges and explores cutting-edge solutions to improve PV performance. A detailed exploration of recent advancements in PV materials, technological innovations, and operational optimizations is provided, based on an analysis of over 7,200 research papers published in the past three years. PV cooling techniques achieved an average efficiency of 83 % with liquid cooling and 74.2 % with heat pump cooling. Using phase change materials improved performance by 35.8 %, while hybrid cooling techniques reduced PV temperatures by an average of 10 °C. Nanofluids enhanced PV efficiency by 13.5 %, and heat-resistant coatings increased thermal efficiency by 16.57 %. Dust caused a 7.4 %–12.35 % power reduction. This review aims to offer insights into the latest strategies for enhancing PV sustainability and efficiency, contributing to the continued advancement of solar energy technologies.

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引用次数: 0

Dual-separation enhanced methane reforming system analysis: Understanding carbon-hydrogen synergy for low-carbon hydrogen production

IF 9.9 1区工程技术 Q1 ENERGY & FUELS

Energy Conversion and Management

Pub Date : 2025-02-01 DOI: 10.1016/j.enconman.2024.119280

Ke Guo , Bin Wang , Xiao Li , Yu Shao , Lingzhi Yang , Yong Hao , Mingkai Liu , Gang Pei

Hydrogen is recognized as a sustainable energy carrier and is expected to play a crucial role in the future energy structure, which has now become a global consensus. However, current hydrogen production primarily relies on fossil fuels, accompanied by the substantial amounts of CO₂ emissions. The conventional sequential approach involves hydrogen production followed by CO₂ capture, with these processes occurring independently, suffering from low hydrogen production efficiency and high CO₂ capture penalty. To address these issues, we proposed an integrated approach that has achieved high-purity hydrogen production and CO₂ capture at mild temperatures ranging from 400 to 500 °C, where the H₂ separation is performed by a Pd-Ag membrane and the in-situ CO₂ capture is performed by sorbents. To evaluate the potential energy and exergy advantages of this integrated method, a systematic analysis of dual-separation enhanced methane reforming is performed using industrial steam methane reforming (SMR) as a reference system, revealing the irreversible loss distribution and reduction mechanism in the process. The results show that the new system achieves an energy efficiency of 79.12 % and an exergy efficiency of 80.01 %, which are 9.34 and 18.19 percentage points higher than those of the industrial SMR, respectively. The enhanced efficiency and reduced irreversible losses are attributed to factors such as the reduction in the grade difference between the energy-donating and energy-accepting sides, the integration of the “reforming-shift-purify-capture” processes, and the reduced energy penalties for dual separation. The equivalent methane consumption is defined and calculated, and the new system has an energy consumption of 0.455 m³-CH₄ m⁻³-H₂, which is 19.9 % lower than that of industrial SMR with CO₂ capture (i.e., sequential approach). The system analysis provides a deeper understanding of the advantages of the integrated hydrogen production system and underscores the significance of the ordered conversion and synergy between carbon-based and hydrogen-based components from methane, clarifying the future optimization directions for the hydrogen production system.

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引用次数: 0

Empirical analysis of bifacial photovoltaic modules in high-latitude regions: Performance insights from a field laboratory in Norway

IF 9.9 1区工程技术 Q1 ENERGY & FUELS

Energy Conversion and Management

Pub Date : 2025-02-01 DOI: 10.1016/j.enconman.2024.119396

Berhane Darsene Dimd, Alfredo Sanchez Garcia, Martin Bellmann

This paper presents a comprehensive empirical analysis of bifacial photovoltaic (bPV) module performance in high-latitude regions, based on data collected from an outdoor field laboratory in Trondheim, Norway. It explores the operational dynamics of bPV systems under environmental challenges such as low irradiation, short daylight hours, low sun angles, and extreme weather conditions, all common in high-latitude regions. The study assesses the performance of various bPV configurations, including vertically oriented modules in east–west (E–W) and south–north (S–N) orientations, fixed south tilted orientations, and orientations equipped with a 2-axis tracking system. Key findings indicate the advantages of mixed orientations in bPV systems, resulting in multiple daily generation peaks that align more closely with consumption profiles. The study demonstrates that bPV modules exhibit a strong response to changes in irradiance than mono-facial modules, particularly to the diffused horizontal irradiance component. This effect is more observed in vertically oriented bPV modules. Yield analysis reveals that spring weather conditions favor PV performance in this region. Additionally, bPV modules show higher performance ratios than monofacial modules in various setups to a different extent, although snow-related reductions are more pronounced in tilted orientations. The results in this work contribute to the optimization of PV systems in regions where low sun angles and snow accumulation are prevalent, emphasizing the potential of vertically oriented bPV modules.

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引用次数: 0

Impact of the reference temperature in dynamic residential hybrid systems according to thermoeconomic analyses

IF 9.9 1区工程技术 Q1 ENERGY & FUELS

Energy Conversion and Management

Pub Date : 2025-02-01 DOI: 10.1016/j.enconman.2024.119403

Arrate Hernández-Arizaga , Ana Picallo-Perez , Luis María López-González , José María Sala-Lizarraga

Buildings’ facilities supplies thermal demand in temperatures close to the surroundings and are dependent to climate variations, so, when applying thermodynamics second principle analyses such as thermoeconomics, the selected reference environment (RE) notably affects the results. This work analyses a hybrid system consisting of a ground source HP and a boiler and quantifies the thermoeconomic effects in terms of unit costs of the fluxes by selecting different dynamic RE: the soil temperature and/or the outdoor temperature. To get the goal, a novel “flexible productive structure” of the HP is defined that allows using any RE and is included in the thermoeconomic software. As a result, the cost of the product of the HP tend to be equal in non-heating season, with both RE, but changes in the heating season when outdoor temperature decreases and the buried evaporator contribution is included in the cost. Therefore, the cost formation process depends on the selected RE and the unit cost decreases when considering the exergy contribution of the ground (1.61c€/kWh less in December). A fact that suggests that choosing the T_soil as RE benefits costs and encourages the use of renewable sources. Besides, the boiler produces DHW, whose costs increment 25.7% from January to August due to the variation of the RE that reduces the value of the product in summer while resource consumption remains constant. This work contributes in the issue of RE selection when using exergy; an essential problem when dealing with energy sources variable with climatic conditions.

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引用次数: 0

The effects of oblique waves on the hydrodynamic characteristics of horizontal axis tidal current turbine 斜波对水平轴潮流水轮机水动力特性的影响

IF 9.9 1区工程技术 Q1 ENERGY & FUELS

Energy Conversion and Management

Pub Date : 2025-02-01 DOI: 10.1016/j.enconman.2024.119350

Fukang Zhang , Yingqin Zhang , Yuzhang Wu , Feiqi Yuan , Gang Xiong , Qihu Sheng

Horizontal axis tidal current turbine (HATCT), as an effective device for obtaining tidal current energy, has received widespread attention and research. The currents and oblique waves in the ocean can evolve into complex flow fields and greatly affect the performance of HATCT, which is rarely studied, so it is necessary to explore the hydrodynamic characteristics of the HATCT under tidal currents and oblique waves. In this study, a wave-current interaction model was developed and combined with the Blade Element Momentum theory, a numerical model for calculating the hydrodynamic characteristics of the HATCT under oblique waves was established and verified. Compared to the computational fluid dynamics method, the numerical method’s computational efficiency has increased by about 869 times. After extensive calculations, the hydrodynamic characteristics of the HATCT were analyzed. Under different wave angles, the main fluctuation frequency of the power coefficient (C_P) or thrust coefficient (C_T) is equal to the wave encounter frequency, and the mean values of the C_P or C_T are almost unchanged. The multimodal phenomenon in the frequency domain of the blade C_P or C_T is affected by the composite frequencies of rotor rotation frequencies and wave encounter frequencies. The beat frequency phenomenon in the C_P or C_T is caused by the difference between the rotor rotation frequencies and wave encounter frequencies. The similarity exists in the C_P or C_T under the symmetrical wave angles.

水平轴潮流水轮机作为一种获取潮汐能的有效装置，受到了广泛的关注和研究。海洋中的海流和斜波可以演变成复杂的流场，对HATCT的性能影响很大，但研究很少，因此有必要对HATCT在海流和斜波作用下的水动力特性进行研究。本文建立了波流相互作用模型，并结合叶片单元动量理论，建立了斜波作用下HATCT水动力特性的数值计算模型并进行了验证。与计算流体力学方法相比，数值方法的计算效率提高了约869倍。经过大量的计算，分析了HATCT的水动力特性。在不同波角下，功率系数（CP）或推力系数（CT）的主波动频率与遇波频率相等，且CP或CT的平均值基本不变。叶片CP或CT频域的多模态现象受转子旋转频率和遇波频率复合频率的影响。CP或CT中的拍频现象是由转子旋转频率与遇波频率的差异引起的。对称波角下的CP和CT存在相似性。

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引用次数: 0

Carnot battery energy storage system integrated with liquid hydrogen cold energy: Thermodynamics, economic analysis and optimization 液氢冷能集成卡诺电池储能系统：热力学、经济分析与优化

IF 9.9 1区工程技术 Q1 ENERGY & FUELS

Energy Conversion and Management

Pub Date : 2025-02-01 DOI: 10.1016/j.enconman.2024.119400

Huilin Zhang , Jianfeng Tang , Meng Qi , Tianbiao He

Carnot battery systems provide a high-energy–density storage solution that is not geographically constrained, converting and storing electricity in thermal form. However, the integration of Carnot batteries with cryogenic energy storage, specifically the utilization of liquid hydrogen cold energy, is an underexplored area. A pioneering design is presented in this study where a Carnot battery system is integrated with a liquid hydrogen cold energy utilization system. Additionally, it captures the waste heat from fuel cells to achieve combined generation of cold, heat, and power. The study includes steady-state modeling, sensitivity analysis of key components, and optimization using a particle swarm optimization algorithm aimed at maximizing power-to-power efficiency. The optimized system achieves a power-to-power conversion efficiency of 1.59, an energy efficiency of 1.02, an exergy efficiency of 0.18, and an Levelized Cost of Storage of 0.1516 USD/kWh. These findings represent a significant advance in energy storage technology, offering a new direction for integrating liquid hydrogen cold energy in energy storage systems and peak power applications.

卡诺电池系统提供了一种不受地理限制的高能量密度存储解决方案，以热形式转换和存储电力。然而，卡诺电池与低温储能的结合，特别是液氢冷能的利用，是一个未被充分开发的领域。在本研究中提出了一种开创性的设计，其中卡诺电池系统与液氢冷能利用系统集成。此外，它还能从燃料电池中捕获废热，实现冷、热、电的联合发电。该研究包括稳态建模，关键部件的灵敏度分析，以及利用粒子群优化算法实现功率对功率效率最大化的优化。优化后的系统功率-功率转换效率为1.59，能源效率为1.02，火用效率为0.18，平准化储能成本为0.1516美元/千瓦时。这些发现代表了储能技术的重大进步，为将液氢冷能集成到储能系统和峰值功率应用中提供了新的方向。

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引用次数: 0

High-efficiency ammonia-fueled hybrid power generation system combining ammonia decomposition, proton exchange membrane fuel cell and micro gas turbine: A thermodynamic model and performance optimization 结合氨分解、质子交换膜燃料电池和微型燃气轮机的高效氨燃料混合发电系统：热力学模型及性能优化

IF 9.9 1区工程技术 Q1 ENERGY & FUELS

Energy Conversion and Management

Pub Date : 2025-02-01 DOI: 10.1016/j.enconman.2024.119358

Li Lin , Mingwei Sun , Yifan Wu , Wenshi Huang , Zeyun Wu , Dabiao Wang , Huihuang Fang , Chongqi Chen , Yu Luo , Qing Zhang , Lilong Jiang

As a carbon-free hydrogen (H₂) carrier with the advantage of liquefaction storage and transportation, ammonia (NH₃) is regarded as a competitive clean energy carrier for H₂ production and power generation. This work designs a novel NH₃-fueled hybrid power generation system, which combines ammonia decomposition reactor (ADR), proton exchange membrane fuel cell (PEMFC) and micro gas turbine (MGT) together with thermochemical recuperation for ADR. A system-level thermodynamic model has been developed to evaluate system performance with different optimization strategies. The model calculation reveals that the NH₃ decomposition temperature drop from 500 °C to 350 °C can increase the energy efficiency from 33.5 % to 43.2 %, and two improved integration strategies have therefore been proposed. Mixing a part of NH₃ with the exhaust gas from PEMFC anode to fuel MGT can reduce the NH₃ decomposition demand and makes better use of waste heat from MGT. Integrating ADR with MGT combustor can lower the exhaust gas temperature and the efficiency loss when using high temperature NH₃ decomposition catalyst. Both strategies can improve the system energy efficiency, to about 40 % and 44 % when NH₃ decomposition temperature is 500 °C and 350 °C, respectively, and demonstrate better flexibility in adapting to changes in NH₃ decomposition temperature.

氨（NH3）作为一种无碳的氢（H2）载体，具有液化储运的优势，被认为是生产和发电中具有竞争力的清洁能源载体。本文设计了一种氨分解反应器（ADR）、质子交换膜燃料电池（PEMFC）和微型燃气轮机（MGT）与ADR热化学回收相结合的新型氨燃料混合发电系统。建立了一个系统级热力学模型来评价不同优化策略下的系统性能。模型计算表明，NH3分解温度从500℃降至350℃，可使能源效率从33.5%提高到43.2%，因此提出了两种改进的集成策略。将部分NH3与PEMFC阳极废气混合用于MGT燃料，可以减少NH3的分解需求，更好地利用MGT的余热。将ADR与MGT燃烧室相结合，可以降低高温NH3分解催化剂的废气温度和效率损失。当NH3分解温度为500℃和350℃时，这两种策略都能提高系统的能效，分别达到40%和44%左右，并且对NH3分解温度的变化具有更好的适应性。

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引用次数: 0

Evolution of supercritical CO2 Rankine cycle configuration for composite waste heat recovery based on ideal cycle with case implementation

IF 9.9 1区工程技术 Q1 ENERGY & FUELS

Energy Conversion and Management

Pub Date : 2025-02-01 DOI: 10.1016/j.enconman.2024.119447

Xianyu Zeng , Hua Tian , Qiyao Zuo , Yu Chen , Cheng Chang , Ligeng Li , Gequn Shu

The optimization design of supercritical CO₂ (S-CO₂) Rankine cycle configuration is crucial for enhancing the efficiency of energy utilization. This paper proposes a framework for cycle configuration evolution based on construction of ideal cycle. An improved sequential Carnot cycle method is proposed and employed to establish ideal Rankine cycle under composite heat sources for the first time. Cycle matching degree, which is defined as the net power output ratio of the actual S-CO₂ Rankine cycle to the ideal Rankine cycle, is used as criterion to evaluate various modified cycle configurations. Then, a specific S-CO₂ Rankine cycle evolution case for composite waste heat recovery from liquid natural gas engine is presented. With the maximum power output of 135.3 kW achieved by the ideal Rankine cycle, analysis results indicate that prioritizing the utilization of the high-temperature heat source is beneficial to approach the superior power output. The basic cycle can only achieve a matching degree of 26.8 %. After cycle evolution, the novel configurations of dual split dual regenerative and triple split dual expansion are obtained. The triple split dual expansion configuration obtains the highest matching degree of 55.6 %, which is significantly close to the ideal cycle. While the dual split dual regenerative cycle achieves the lowest specific investment cost of 5075 $/kW. This framework delineates a clear path for the evolution of cycle configurations, offering invaluable guidance to engineering and technical professionals.

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引用次数: 0

Sustainability assessment of a petrochemical plant electricity supply based on 4E optimization of various hybrid renewable energy systems scenarios

IF 9.9 1区工程技术 Q1 ENERGY & FUELS

Energy Conversion and Management

Pub Date : 2025-02-01 DOI: 10.1016/j.enconman.2024.119357

Samaneh Habibzadeh, Fatemeh Razi Astaraei, Mohammad Hossein Jahangir

Sustainable electricity production is a key objective for many nations, achievable through hybrid renewable energy systems. This article examines sustainability within the industrial sector by integrating social indicators alongside environmental and economic indicators into the Pareto front solutions of various hybrid renewable energy systems for prioritization. It presents new findings on sustainability indicators for four configurations of hybrid renewable energy systems—photovoltaic panels, wind turbines, and wave energy converters—and proposes a systematic decision-making approach for their assessment and planning. The methodology is validated with a case study on a coastal city in Iran. Various hybridization scenarios are modeled and optimized considering the cost of electricity (economic), CO₂ emissions (environmental), loss of power supply probability (reliability), and exergy efficiency (technical) to obtain the Pareto front. Sustainability indicators are subsequently employed to prioritize the various configurations and the Pareto-optimal solutions associated with each configuration. Results show that solar + wind is the most sustainable configuration, with a sustainability indicator of 0.89, followed by solar + wind + wave energy converter (0.63), solar (0.46), and solar + wave energy converter (0.63). As a novel contribution, the detrimental effect of humidity on PV output is evaluated in the optimization. The study also examines the impact of performance improvements on sustainability, considering the maximum achievable improvements for each technology by 2030. A sensitivity analysis is conducted to verify model accuracy and examine cost performance concerning uncertain parameters.

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引用次数: 0