内燃机余热回收冷热电联供系统性能研究

Performance analysis on a combined cooling,heating and power system for waste heat recovery of internal combustion engine

针对内燃机排气的特点,构建了一种新型冷热电联产(CCHP)系统来进一步回收排气余热,达到节能减排的目的。该CCHP系统由1个简单回热超临界二氧化碳(S-CO_(2))布雷顿循环、1个喷射式制冷循环和1个热水器组成。为了评估系统性能,建立了系统的热力学模型,并比较了单一S-CO_(2)循环与CCHP系统的性能参数。此外通过参数分析,研究了压缩机出口压力、透平1进口温度以及制冷蒸发温度3个重要参数对于系统性能的影响。最后,以系统同时产生最大净输出功和制冷量(CCP模式)或同时产生最大净输出功和供热量(CHP模式)为优化运行模式,对系统进行了多目标优化。结果表明:CCP模式下,系统净输出功、制冷量、供热量之和为546.87 kW,热效率和㶲效率分别为45.81%和50.55%;而在CHP模式下,同样的性能指标则分别为501.35 kW、41.95%和50.46%。

Based on the characteristics of internal combustion engine exhaust gas,a novel combined cooling,heating and power(CCHP)system is constructedto further recovertheexhaust heat and achieve the purpose of energy saving and emission reduction.The CCHP system consists of a simple regenerative supercritical carbon dioxide(S-CO_(2))Brayton cycle,anejectiverefrigeration cycleand a hot water heatexchanger.Thethermodynamic model of the proposed system is established to evaluate the system performance,and a comparative analysis is conducted between the single S-CO_(2) cycle and the proposed CCHP system.In addition,parametric analysisis conductedto investigate the effects ofthree important operating parameters,including the compressor outlet pressure,turbine 1 inlet temperature and refrigeration evaporation temperature,onthesystem performance.Finally,multi-objective optimization is performed for the system when it generates the maximum cooling and power(CCP model)or simultaneously produces the maximum heat and power(CHP model).The results show that,inthe CCP model,thesum of the system net output power,cooling capacityandheating capacity is546.87 kW,the thermal efficiency and exergy efficiency of the system are 45.81%and 50.55%,respectively.While in CHP model,the corresponding indexes change into501.35kW,41.95%and 50.46%.