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waste heat recovery from heavy-duty diesel engine exhaust gases by medium temperature ORC system

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Science China(Technological Sciences) 2011年第10期54卷 2746-2753页

作者： WEI MingShan FANG JinLi MA ChaoChen DANISH Syed Noman School of Mechanical Engineering Beijing Institute of Technology Beijing 100081 China National University of Sciences and Technology (NUST) Islamabad H-12 Pakistan

A medium-temperature waste-heat recovery system based on the organic Rankine cycle (ORC) is designed to recover the exhaust energy from a heavy-duty diesel engine. Analysis of the 1st law of thermodynamics for an ORC system is performed. This analysis contains two parts. The first part is an analysis with undefined heat exchangers to gain an understanding of the ORC and find out suitable organic fluid parameters for a better ORC efficiency. The second part of the analysis uses combined engine test results and two designs of heat exchangers. By comparing the two designs, an improved system of heat exchangers is described. This analysis also quantifies the effect of engine parameters on ORC system. The study concludes that the supercritical Rankine cycle is a better approach towards waste heat recovery. The ORC system is found to perform better under part-load conditions if the medium-high power condition rather than rated working point of the engine is used as the design parameter. The ORC system achieves the highest waste-heat recovery efficiency of up to 10-15% for the optimised heat ex-changer design.

关键词： waste heat recovery organic-fluid Rankine cycle heavy-duty diesel engine medium temperature waste heat

Experimental Analysis of Atypically Long Finned Oscillating heat Pipe for Ventilation waste heat recovery Application

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Journal of Thermal Science 2020年第3期29卷 667-675页

作者： MAHAJAN Govinda CHO Heejin SMITH Aaron THOMPSON Scott M. Rheem Manufacturing MontgomeryAL 36109USA Department of Mechanical Engineering Mississippi State UniversityMsissippi StateMS 39762USA Department of Mechanical Engineering Auburn UniversityAubumnAL 36849USA

Oscillating heat pipes(OHP)which are constructed from a serpentine-arranged capillary tube possess a desirable aerodynamic form factor and provide for relatively high heat transfer rates via cyclic evaporation and condensation of an encapsulated working fluid with no internal wicking structure *** last two decades,OHP has been extensively investigated for its potential application in thermal management of various *** study presents an experimental investigation on the heat transfer performance of an atypically long finned *** heat transfer performance of the proposed OHP was analyzed and compared with a bare tube OHP with similar overall *** show that a unit row of finned OHP filled with n-pentane with fill ratio of 70%can recover up to(400±40)W of heat from a typical waste exhaust air *** additional pressure drop due to fins was estimated to be(6.8±2)Pa resulting in an increase of 1–2 W of fan power *** average heat recovery rate via finned OHP was found to be almost 80%more than bare tube OHP filled with same working fluid with same fill ratio.

关键词： oscillating heat pipe waste heat recovery ventilation

Analysis of an electricity-cooling cogeneration system for waste heat recovery of gaseous fuel engines

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Science China(Technological Sciences) 2015年第1期58卷 37-46页

作者： SHU GeQun WANG Xuan TIAN Hua LIANG YouCai LIU Yu LIU Peng State Key Laboratory of Engines Tianjin University

waste heat recovery(WHR)is one of the most useful ways to improve the efficiency of internal combustion engines,and an electricity-cooling cogeneration system(ECCS)based on Rankin-absorption refrigeration combined cycle for the WHR of gaseous fuel engines is proposed in the *** system can avoid wasting the heat in condenser so that the efficiency of the whole WHR system improves,but the condensing temperature of Rankin cycle(RC)must increase in order to use absorption refrigeration system,which leads to the decrease of RC output ***,the relationship between the profit of absorption refrigeration system and the loss of RC in this combined system is the mainly studied content in the *** the energy quality of cooling and electricity are different,cooling power in absorption refrigeration is converted to corresponding electrical power consumed by electric cooling system,which is defined as equivalent electrical *** this method,the effects of some important operation parameters on the performance of the ECCS are researched,and the equivalent efficiency,exergy efficiency and primary energy rate are compared in the paper.

关键词： gaseous fuel engines waste heat recovery electricity-cooling cogeneration Rankin cycle absorption refrigeration

Overall optimization of Rankine cycle system for waste heat recovery of heavy-duty vehicle diesel engines considering the cooling power consumption

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Science China(Technological Sciences) 2016年第2期59卷 309-321页

作者： YANG Can XIE Hui ZHOU Sheng K State Key Laboratory of Engines Tianjin University

The Rankine cycle system for waste heat recovery of heavy-duty vehicle diesel engines has been regarded as a promising tech- nique to reduce fuel consumption. Its heat dissipation in the condensation process, however, should be take：l away in time, which is an energy-consuming process. A fan-assisted auxiliary water-cooling system is employed in this paper. Results at 1300 r/min and 50% load indicate that the cooling pump and cooling fan together consume 7.66% of the recovered power. What＇s worse for the heavy load, cooling accessories may deplete of all the recovered power of the Rankine cycle system. Af- terwards, effects of the condensing pressure and water feeding temperature are investigated, based on which a cooling power consumption model is established. Finally, an overall efficiency optimization is conducted to balance the electric power gener- ation and cooling power consumption, taking condensing pressure, pressure ratio and exhaust bypass valve as major variables. The research suggests that the priority is to increase condensing pressure and open exhaust bypass valve appropriately at high speed and heavy load to reduce the cooling power consumption, while at low speed and light load, a lower condensing pressure is favored and the exhaust bypass valve should be closed making the waste heat recovered as much as possible. Within the sub-critical region, a larger pressure ratio yields higher overall efficiency improvement at medium-low speed and load. But the effects taper off at high speed and heavy load. For a given vehicular heavy-duty diesel engine, the overall e：＇ficiency can be improved by 3.37% at 1300 r/min and 25% load using a Rankine cycle system to recover exhaust energy. The improvement becomes smaller as engine speed and load become higher.

关键词： vehicular diesel engines Rankine cycle system cooling power consumption waste heat recovery overalloptimization

Energy management strategy for hybrid electric vehicle integrated with waste heat recovery system based on deep reinforcement learning

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Science China(Technological Sciences) 2022年第3期65卷 713-725页

作者： WANG Xuan WANG Rui SHU GeQun TIAN Hua ZHANG XuanAng State Key Laboratory of Engines Tianjin UniversityTianjin 300072China

Hybrid electric vehicles(HEVs)are acknowledged to be an effective way to improve the efficiency of internal combustion engines(ICEs)and reduce fuel *** the ICE in an HEV can maintain high efficiency during driving,its thermal efficiency is approximately 40%,and the rest of the fuel energy is discharged through different kinds of waste ***,it is important to recover the engine waste *** of the great waste heat recovery performance of the organic Rankine cycle(ORC),an HEV integrated with an ORC(HEV-ORC)has been ***,the addition of ORC creates a stiff and multi-energy problem,greatly increasing the complexity of the energy management system(EMS).Considering the great potential of deep reinforcement learning(DRL)for solving complex control problems,this work proposes a DRL-based EMS for an *** simulation results demonstrate that the DRL-based EMS can save 2%more fuel energy than the rule-based EMS because the former provides higher average efficiencies for both engine and motor,as well as more stable ORC power and battery ***,the battery always has sufficient capacity to store the ORC ***,DRL showed great potential for solving complex energy management problems.

关键词： hybrid electric vehicles organic Rankine cycle waste heat recovery deep reinforcement learning energy management system

Energy,Exergy,and Exergoeconomic Analysis of Solar-Driven Solid Oxide Electrolyzer System Integrated with waste heat recovery for Syngas Production

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Journal of Thermal Science 2023年第1期32卷 135-152页

作者： WANG Jiangjiang YAO Wenqi CUI Zhiheng GAO Yuefen Hebei Key Laboratory of Low Carbon and High-Efficiency Power Generation Technology North China Electric Power UniversityBaoding 071003China

Syngas fuel generated by solar energy integrating with fuel cell technology is one of the promising methods for future green energy solutions to carbon *** paper designs a novel solar-driven solid oxide electrolyzer system integrated with waste heat for syngas *** photovoltaic and parabolic trough collecter together drive the solid oxide electrolysis cell to improve system *** thermodynamic models of components are established,and the energy,exergy,and exergoeconomic analysis are conducted to evaluate the system’s *** the design work conditions,the solar photovoltaic accounts for 88.46%of total exergy destruction caused by its less conversion *** exergoeconomic analysis indicates that the fuel cell component has a high exergoeconomic factor of 89.56%due to the large capital investment *** impacts of key parameters such as current density,operating temperature,pressure and mole fraction on system performances are *** results demonstrate that the optimal energy and exergy efficiencies are achieved at 19.04%and 19.90%when the temperature,pressure,and molar fraction of H_(2)O are 1223.15 K,0.1 MPa,and 50%,respectively.

关键词： solid oxide electrolysis cell(SOEC) solar fuel thermodynamic analysis exergoeconomic analysis waste heat recovery

A four-dimensional interaction-based appraisal approach towards the performance enhancement of a vehicular waste heat recovery system

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Science China(Technological Sciences) 2022年第12期65卷 2921-2941页

作者： LU BoWen SHI LingFeng TIAN Hua WANG Xuan ZHANG MeiYan SHU GeQun Department of Thermal Science and Energy Engineering University of Science and Technology of ChinaHefei 230027China State Key Laboratory of Engines Tianjin UniversityTianjin 300072China

The non-linear multifactorial impacts on fuel-saving potential constrain the practical performance of the vehicular waste heat recovery system(WHRS). This study proposed a four-dimensional interaction-based appraisal approach to interpreting these impacts for enhancing WHRS's in-vehicle performance. The interaction incorporates a heat exchanger, configuration, engine,and vehicle. The proposed approach comprises two successive steps, emphasizing evaluation under the rated(Step 1) and off-design(Step 2) heat source conditions. A case study of waste heat recovery from a passenger vehicle was conducted to evaluate the in-vehicle performance of a novel co-split system and two single-split ones(with/without a regenerator) through this approach. The novel system theoretically modifies vehicular performance but remains ambiguous concerning real-world behaviour, which is assessed and verified by the proposed approach. Two key factors determining vehicular performance were identified by Step 1, namely, net power output and engine backpressure. As the co-split system modified both factors, its fuel-saving potential could be increased by up to 20.3% compared with single-split systems. Also, the limiting factor for off-design performance was pinpointed by Step 2, namely, the mismatch between the heat source and working fluid, which led to the solution, i.e., the synergistic split regulation of the working fluid and heat source. An up to 8.8% improvement in net power output was achieved by the co-split system at off-design heat sources compared with fixed split ratios. Consequently, the approach enables holistic performance improvement of the vehicular WHRS under design/off-design heat source conditions.

关键词： waste heat recovery passenger vehicle in-vehicle scenario dual heat source operational flexibility

A review of concentrated photovoltaic-thermal(CPVT) hybrid solar systems with waste heat recovery(WHR)

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Science Bulletin 2017年第20期62卷 1388-1426页

作者： Xing Ju Chao Xu Zhirong Liao Xiaoze Du Gaosheng Wei Zhifeng Wang Yongping Yang Key Laboratory of Condition Monitoring and Control for Power Plant Equipment of Ministry of Education School of Energy Power and Mechanical Engineering North China Electric Power University Key Laboratory of Solar Thermal Energy and Photovoltaic Systems Institute of Electrical Engineering Chinese Academy of Sciences

In conventional photovoltaic(PV) systems, a large portion of solar energy is dissipated as waste heat since the generating efficiency is usually less than 30%. As the dissipated heat can be recovered for various applications, the wasted heat recovery concentrator PV/thermal(WHR CPVT) hybrid systems have been developed. They can provide both electricity and usable heat by combining thermal systems with concentrator PV(CPV) module, which dramatically improves the overall conversion efficiency of solar *** paper systematically and comprehensively reviews the research and development of WHR CPVT systems. WHR CPVT systems with innovative design configurations, different theoretical evaluation models and experimental test processes for several implementations are presented in an integrated manner. We aim to provide a global point of view on the research trends, market potential, technical obstacles, and the future work which is required in the development of WHR CPVT technology. Possibly, it will offer a generic guide to the investigators who are interested in the study of WHR CPVT systems.

关键词： Hybrid solar system waste heat recovery Photovoltaic/thermal Concentration Concentrator photovoltaic/thermal

Thermodynamic and Economic Studies of a Combined Cycle for waste heat recovery of Marine Diesel Engine

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Journal of Thermal Science 2022年第2期31卷 417-435页

作者： ZHANG Xinxin CAO Min HE Maogang WANG Jingfu MOE key laboratory of enhanced heat transfer and energy conservation Beijing University of TechnologyBeijing 100124China Beijing key laboratory of heat transfer and energy conversion Beijing University of TechnologyBeijing 100124China MOE Key Laboratory of Thermo-Fluid Science and Engineering School of Energy and Power EngineeringXi'an Jiaotong UniversityXi’an 710049China

In the present study,the thermodynamic and economic performance of a combined thermodynamic cycle formed by an ORC and a Kalina cycle,which can simultaneously recover waste heat of exhaust gas and cooling water of marine engine,has been *** typical marine engines are selected to be the waste heat *** economic indicators are used to analyze the economic performance of this combined thermodynamic cycle system with different marine engine load and under practical comprehensive operating condition of marine *** results of the present study show that the combined thermodynamic cycle system with R123 as organic working fluid has the best *** system with cis-butene has the worst economic *** practical comprehensive operating conditions of ships,R123 has the shortest Payback Periods,which are 8.51 years and 8.14 years for 8 S70 ME-C10.5 engine and 5G95 ME-C10.5 engine,***,payback Periods of Cyclopentane are 11.95 years and 11.90 *** above values are much shorter than 25 years which are the lifetime of a marine *** practical comprehensive operating conditions of ships,the combined cycle system can provide output power which is at least equivalent to 25%of engine *** that R123 will be phased out in near future,cyclopentane may be its good *** can be used safely by correct handling and installing according to manufacturer's instructions.

关键词： marine engine waste heat recovery combined thermodynamic cycle thermodynamic and economic study R123 cyclopentane