Investigation of a mixed effect absorption chiller powered by jacket water and exhaust gas waste heat of internal combustion engine

CCHP (combined cooling heating and power) system based on ICE (internal combustion engine) has been widely used. A key issue is to efficiently recover the jacket water and exhaust gas waste heat for refrigeration. In this work, a mixed effect absorption chiller (AC), which couples single effect and double effect processes together, is investigated to recover these two kinds of waste heat simultaneously. The high pressure generator is powered by exhaust gas while one low pressure generator is powered by jacket water waste heat. Thermodynamic characteristics and off-design performance are simulated. Considering thermodynamic constraints, the start point temperature in low pressure generator should be 77°Cor lower. For a 16 kW ICE, the cooling output can reach 34.4 kW with COP of 0.96 and exergy efficiency of 0.186. Comparing with double effect or single effect AC, it can make a better use of different waste heat in CCHP system.     

Experimental investigation of a micro-combined cooling, heating and power system driven by a gas engine

An experimental investigation of the performance of a micro-combined cooling, heating and power (CCHP) system is described. The natural gas and LPG-fired micro-CCHP system uses a small-scale generator set driven by a gas engine and a new small-scale adsorption chiller, which has a rated electricity power of 12 kW, a rated cooling of 9 kW and a rated heating capacity of 28 kW. Silica gel–water is used as working pair in the adsorption cooling system. The refrigeration COP of the adsorption chiller is over 0.3 for 13 °C evaporation temperature. The test facility designed and built is described, which supplies better test-rig platform for cooling, heating and power cogeneration. Experimental methodology of this system is presented and the results are discussed. An energetic analysis of micro-CCHP system is performed as well. The overall thermal and electrical efficiency is over 70%.     

Simulation of an ammonia-water heat pump water heater with combustion products-driven evaporator

The objective of this work is to simulate a single effect (SE) ammonia-water heat pump for domestic water heating, with innovative aspects for cycle simulation and eventual practical implementation. The following practical difficulties are addressed in the simulation: 1. seasonal temperature variations change the operating conditions of the distillation column, calling for insightful design to maintain a suitable refrigerant concentration in all seasons, and particularly in winter; 2. The evaporator activated by outdoor air suffers from immoderate heat transfer requirements, and these demands are considerably reduced if the activation is done by products of combustion; 3. Pumps have head requirements that can be assuaged by judicious selection and inlet solution subcooling. The variables that need to be controlled if the same column is to be used all year round are specified. As configured with the innovations mentioned, the cycle simulation yields a coefficient of performance within the expected range for a single effect, but it harbors the promise of a much smaller evaporator, of small overall height, and of a distillation column capable of operating effectively all year round with the same feed point.     

内燃机燃烧测试分析系统的设计与开发

开发一套基于PC机的内燃机燃烧测试分析系统,并对气缸压力的采集,数据的匀化、光顺处理,动态上止点位置的确定等做介绍。利用测量的气缸压力曲线和能量守恒原理,在LabVIEW软件平台上编写出内燃机燃烧放热率计算程序,研究主要经验参数对放热率及缸内平均温度的影响。结果表明:采用Woschni传热公式计算的放热率曲线值高于采用Eichelberg传热公式和Sitkei传热公式计算的放热率曲线值。扫气系数φs的变化对气缸内平均温度有显著影响,φs=0.99时的缸内平均温度明显高于φs=0.95时的缸内平均温度,两者最高温度相差81.4 K。     

Graphicoanalytical method for calculation of heat transfer through the piston of an internal combustion engine

Using a quantitative estimate of deposit formation on the pistons of a diesel engine and results of engine thermometry, a graphicoanalytical method is developed for calculation of heat transfer through an oil-cooled piston.Notation T_m mean resultant gas temperature in engine cylinder - t_h temperature of heated side of piston - t_c temperature of cooled piston surface - t_o temperature of cooling oil - q specific thermal flux through piston - P_e mean effective engine pressure - C_m mean piston speed - T_i injected air temperature, °K - P_i injected air pressure - g_e effective fuel flow rate - mean thickness of piston bottom - thermal-conductivity coefficient of piston bottom - Z number of strokes in engine cycle - _w gas-to-wall heat-transfer coefficient - _o wall-to-oil heat-transfer coefficient - R total thermal resistance Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 37, No. 5, pp. 918–925, November, 1979.     

Effect of carbon on heat transfer through a piston of an internal combustion engine

By analyzing and correlating the results of thermometrization of a 11D45 diesel we estimate the effect of carbon in oil-cooling channels on parameters for heat transfer through a piston.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 38, No. 3, pp. 538–542, March, 1980.     

电磁式发动机水冷系统流固耦合传热研究

针对电磁式发动机电磁线圈由工作温度过高导致其内阻过大、发动机工作效率降低的问题,应用流固耦合传热理论对发动机水冷系统的传热性能进行研究.以电磁式发动机水冷系统流场和固场为研究对象,建立流固耦合传热的数学模型;利用UG(Unigraphics)软件建立水冷系统流固耦合模型,对水冷系统的流场和温度场分布进行仿真分析.结果表...     

R1234ze(E)在冷藏车余热驱动型TORC-制冷循环系统运行性能分析

建立了冷藏车余热驱动型跨临界有机朗肯-制冷循环系统热力学计算模型,研究了R1234ze(E)在该循环系统中运行性能,系统地分析了冷凝温度为40℃、50℃、60℃时系统运行性能参数,得到冷凝温度为40℃时,对应发动机尾气温度约为140℃时,系统拥有最高的膨胀机做功量10.20 kW;对应发动机尾气温度约为165℃,系统拥有最优的TORC系统热效率9.49%和最大的TORC-制冷循环系统制冷量18.36kW以及最佳的热效率值19.12%。     

尾气余热驱动的氨-盐吸收式制冷系统性能试验研究

设计可在空调工况、低温工况和冷冻冷藏工况下运行的以尾气余热驱动的氨-盐吸收式制冷系统,搭建相应的试验装置对该系统进行热力性能及变工况特性试验。结果显示:在冷却水温度30℃,蒸发温度-0.3℃,冷凝温度30℃工况下,该系统最大制冷量可达4.60 kW,基于电功率的COPe可达17.69;系统最低蒸发温度可达-25.20℃。研究结果可为尾气余热利用技术提供参考。     

具有热阻、热漏和内不可逆性的联合卡诺热机生态学优化

用有限时间热力学的方法分析具有热阻、热漏、内不可逆性的定常流联合卡诺型热机循环．导出了在傅立叶导热定律下联合循环功率、效率和生态学指标的性能，并进行优化；得到功率、效率和生态学指标之间的优化关系，并由数值计算分析了功率、效率和循环熵产率之间的关系．所得的结果表明，最大生态学指标下的效率十分接近于联合循环可以达到的最大效率；相应的熵产率也要低于以输出功率为优化目标时的熵产率．     

Calculation of the gas dynamics of compression in a cylinder of an internal combustion engine with combustion chambers of different shape

The velocity and temperature fields for different shapes of the surface of the cylinder are presented. The computed and experimental average profiles of the velocity and intensity of turbulence are compared.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 57, No. 2, pp. 285–291, August, 1989.     

GTCC排烟驱动的热管型溴冷机设计及传热分析

针对环境温度升高导致燃气轮机性能下降问题,提出利用GTCC烟气余热驱动热管型溴化锂吸收式制冷机制取冷量,以降低压气机进气温度,提高燃气轮机性能。介绍热管型溴冷机的工艺流程,分析分离式热管换热器的传热性能,应用VB软件编制计算程序,对热管型溴冷机进行具体设计及分析。结果表明,GTCC排烟驱动的热管型溴冷机运行费用低,换热效率高,能够综合利用能源。     

Analysis of recoverable waste heat of circulating cooling water in hot-stamping power system

This article studies the possibility of using heat pump instead of cooling tower to decrease temperature and recover waste heat of circulating cooling water of power system. Making use of heat transfer theory the article carried on analysis and calculation about recoverable waste heat of circulating cooling water in hot-stamping power system which includes hot-stamping, closing-in and extrusion intermediate frequency induction furnace. The results show that the whole process can recover a calorie which is 2.642 × 10⁶ kJ per hour. Using the recycled calories can make 15.82 tons hot water per hour which is 60 °C. So it can reduce burning capacity of coal 180.29 kg/h. The hot water can provide the needed water for production and workers bathing. This research shows that using heat pump to recover the waste heat of circulating cooling water is effectual. Realizing the use of waste heat, it can reduce pollution of condensing heat, reduce operating cost and noise of cooling tower, reduce site and the occupation of equipment, improve the production efficiency, and can also save the natural resources (fossil fuel-coal) and reduce the cost of needed hot water production.     

Experimental study on performance of a biogas engine driven air source heat pump system powered by renewable landfill gas

The equipment configuration of a landfill gas (LFG) fueled biogas engine driven air source heat pump system was studied. The process flow for collecting and purifying LFG was analyzed, and the LFG collection and purification method was determined. An experimental apparatus was set up, and the effect of biogas engine speed variation on LFG consumption, exhaust fume temperature of biogas engine, recovered waste heat from exhaust fume and cylinder liner, coefficient of performance (COP) of the heat pump and primary energy ratio (PER) of the system were experimentally tested. The results indicated that LFG consumption and biogas engine exhaust fume temperature increased with biogas engine speed. When the biogas engine operated in the 70%–90% rated speed range, the system heat output and exhaust fume waste heat recovery rate would be relatively higher. In addition, the maximum COP and PER reached 4.2 and 1.4 respectively.     

Optimal design of an absorption chilled water storage air conditioning system driven by waste heat

In order to meet both economic and energy requirements, this study has proposed an optimal design to minimize the sum of the initial and operation energy costs for a 1200 refrigeration ton chiller and 12 water storage tanks in an absorption chilled water storage air conditioning system. Various power consumption calculation methods for the main devices are included to predict the performance of this equipment under different operating conditions. In addition, the performance curves of the water storage tank under the storage and discharge modes are calculated using Fluent software. The article uses five control strategies for a cooling tower along with three hot water inlet temperatures of a generator to simulate the optimal design of a system. The results show that the least power (10,336 kWh) is consumed when the cooling tower’s outlet temperature is 32°C and the generator’s inlet hot water temperature is 105°C.     

Some principles of combustion of homogeneous fuel-air mixtures in the cylinder of an internal combustion engine

An algorithm is presented for the problem of flame propagation rate in combustion of a homogeneous fuel-air mixture in the cylinder of an internal combustion engine. It is assumed that the mixture is not overturbulized and that the flame front is spherical. The model used for the phenomenon is based on a turbulent transport mechanism. In the near-wall region the combustion mechanism follows a fine-scale mechanism, but in the core, a large-scale mechanism.Experiments permitted determination of the character and numerical value of coefficients which consider the effect of turbulence on flame front propagation in the combustion chamber of a ZMZ-4021 engine.The principles presented can be used as the basis of an algorithm for heat liberation rate in an internal combustion engine with external mixture formation.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 59, No. 6, pp. 942–947, December, 1990.     

基于Modelica的生物质燃气内燃机性能模拟研究

针对由沼气成分及其理化特性导致的内燃机燃用沼气时会发生燃烧速度慢、后燃严重、排气温度高等问题,将生物质燃气内燃机作为研究对象,基于可重用性及面向对象的Modelica语言建立内燃机模型库,将生物质燃气为燃料对四缸四冲程火花点火内燃机性能进行分析.通过仿真研究不同比例天然气(体积分数分别为33%,67%及100%)和LP...     

Cost effective simulation-based multiobjective optimization in the performance of an internal combustion engine

Solving real-life engineering problems can be difficult because they often have multiple conflicting objectives, the objective functions involved are highly nonlinear and they contain multiple local minima. Furthermore, function values are often produced via a time-consuming simulation process. These facts suggest the need for an automated optimization tool that is efficient (in terms of number of objective function evaluations) and capable of solving global and multiobjective optimization problems. In this article, the requirements on a general simulation-based optimization system are discussed and such a system is applied to optimize the performance of a two-stroke combustion engine. In the example of a simulation-based optimization problem, the dimensions and shape of the exhaust pipe of a two-stroke engine are altered, and values of three conflicting objective functions are optimized. These values are derived from power output characteristics of the engine. The optimization approach involves interactive multiobjective optimization and provides a convenient tool to balance between conflicting objectives and to find good solutions.     

Exergy analysis of gas turbine trigeneration system for combined production of power heat and refrigeration

A conceptual trigeneration system is proposed based on the conventional gas turbine cycle for the high temperature heat addition while adopting the heat recovery steam generator for process heat and vapor absorption refrigeration for the cold production. Combined first and second law approach is applied and computational analysis is performed to investigate the effects of overall pressure ratio, turbine inlet temperature, pressure drop in combustor and heat recovery steam generator, and evaporator temperature on the exergy destruction in each component, first law efficiency, electrical to thermal energy ratio, and second law efficiency of the system. Thermodynamic analysis indicates that exergy destruction in combustion chamber and HRSG is significantly affected by the pressure ratio and turbine inlet temperature, and not at all affected by pressure drop and evaporator temperature. The process heat pressure and evaporator temperature causes significant exergy destruction in various components of vapor absorption refrigeration cycle and HRSG. It also indicates that maximum exergy is destroyed during the combustion and steam generation process; which represents over 80% of the total exergy destruction in the overall system. The first law efficiency, electrical to thermal energy ratio and second law efficiency of the trigeneration, cogeneration, and gas turbine cycle significantly varies with the change in overall pressure ratio and turbine inlet temperature, but the change in pressure drop, process heat pressure, and evaporator temperature shows small variations in these parameters. Decision makers should find the methodology contained in this paper useful in the comparison and selection of advanced heat recovery systems.