DCCHP排烟余热耦合空气源热泵系统性能分析

内燃机冷热电联供系统作为一种高效的能源利用方式,排烟余热回收后的排放温度在100℃左右,仍有部分低温余热没有充分利用,提出一种分布式冷热电三联供（distributed combined cooling heating and power,DCCHP）动力排烟低温余热耦合空气源热泵系统,实现了排烟余热的深度回收。以10 kW内燃机冷热电联供为基础,研究了该系统可回收余热量、热泵循环性能系数（coefficient of performance,COP）以及对一次能源利用率的影响。结果表明：在设计工况下,DCCHP系统排烟余热1.22 kW,热泵系统回收余热量可达1.07 kW,排烟余热回收率达到87.7%;热泵COP高达4.66,提高39.5%;系统一次能源利用率提高3.9%;同时解决了寒冷地区冬季热泵机组蒸发器结霜、低温环境下运行性能差的问题。此研究为冷热电联供系统与热泵机组的联合高效应用提供了重要的参考。     

夏季冷热联供模式下的燃气机热泵机组性能分析

本文建立了一套以R134a为制冷剂工质、以天然气为一次能源驱动开启式压缩机做功的燃气机热泵系统,研究了当蒸发器进水温度为12～22℃,室外环境温度为24.2～35.6℃,发动机转速为1 400～2 000 r/min,夏季冷热联供模式时,空气源燃气机热泵(GEHP)机组的性能。结果表明:发动机转速和蒸发器进水温度的变化对系统性能的影响大于室外环境温度变化的影响。随着发动机转速由1 400 r/min增至2 000 r/min,系统COP_1、COP_2、PER_1、PER_2分别减小了15.5%、9.9%、18.8%、13.5%。在工况范围内,机组冷水出水温度可达6.7～19.3℃,热水出水温度可达40.7～61.7℃,考虑余热回收情况下系统PER_2可达1.14～1.45。     

Simulation and validation of a hybrid-power gas engine heat pump

Hybrid-power gas engine heat pump (HPGHP) combines hybrid power technology with gas engine heat pump, which can keep the gas engine working in the economical zone. In this paper, a steady-state model of the HPGHP in heating condition has been established, the optimal torque curve control strategy is proposed to distribute power between the gas engine and battery pack. The main operating parameters of the HPGHP system are simulated on Matlab/Simulink and validated by experimental data, such as operating temperature, coefficient of performance (COP), fuel-consumed rate, etc. Heating capacity and COP of the heating pump system are validated under different ambient temperatures and water flow rates. The simulation and experiment results shows acceptable agreement, the maximum difference is respectively 8.9%, 5.9%, 9.5% and 8.2% for engine torque, motor torque, reclaimed heat and fuel-consumed rate. Based on the simulation results, HPGHP has the lowest fuel-consumed rate of 283 g (kWh)⁻¹ at engine speed of 3000 rpm; the PER of HPGHP system is about 15.9% and 11.4% higher than the GHP under the same load in Mode C and D.     

沼气机压缩式热泵系统的构建与经济性分析

由沼气发动机驱动的热泵（BHP）除能够保证一般热泵功能外,还能够充分回收利用沼气发动机的余热。根据对BHP的系统构建及一次能源利用率（PER）的计算结果,分析BHP系统的经济性及其对环境保护的作用。结果表明：BHP系统在经济性及环保方面都具有明显的经济价值和现实意义。     

燃气发动机热泵及性能分析

介绍了燃气发动机热泵系统的构成及其工作原理，说明燃气发动机热泵的使用可减少空调／供热的用电量，缓解由空调／供热引起的电力紧张状况，降低电网的峰谷差，同时可调节燃气消耗量的季节不均衡性，并有利于环境保护。根据空调／供热系统的不同方式，给出了比较这些系统能源利用率的统一指标——次能源利用率，并利用一次能源利用率分析了六种供热系统的能源利用率，分析结果表明燃气发动机热泵的一次能源利用率最高，可节省能源。文章对燃气发动机热泵的性能进行了测试，一次能源利用率达到1．76。     

低温热泵系统中R290替代R22的性能研究及优化

本文针对低温热泵系统,采用R290替代R22进行性能实验研究,对比不同工况下两者的性能差异发现:直接在原系统中将R22抽出并灌装非等量R290后,系统运行时,换热量与COP均有所衰减,且在相同的低温环境工况下,R290系统的压缩机排气温度和排气压力均高于原R22系统。通过分析系统部件可知,上述现象出现的主要原因是R22系统压缩机排量过大、与R290系统不匹配,因此为同时满足系统的安全性要求以及提高R290在低温热泵系统中的整体性能,考虑在系统中更换与R290更为匹配的排量更小的压缩机。实验结果表明:对R290低温热泵系统压缩机排量进行优化能有效降低系统的排气温度和压力、提高系统整体性能;压缩机优化后的R290低温热泵系统COP较原R22系统提高6.5%,低温环境下排气温度降低36%,至80℃以下。     

Thermal modeling of gas engine driven air to water heat pump systems in heating mode using genetic algorithm and Artificial Neural Network methods

The gas-engine driven air-to-water heat pump, type air conditioning system, is composed of two major thermodynamic cycles (including the vapor compression refrigeration cycle and the internal combustion gas engine cycle) as well as a refrigerant-water plate heat exchanger. The thermal modeling of gas engine driven air-to-water heat pump system with engine heat recovery heat exchangers was performed here for the heating mode of operation (in which it was required to model engine heat recovery heat exchanger). The modeling was performed using typical thermodynamic characteristics of system components, Artificial Neural Network and the multi-objective genetic algorithm optimization method. The comparison of modeling results with experimental ones showed average differences of 5.08%, 5.93%, 5.21%, 2.88% and 6.2% which shows acceptable agreement for operating pressure, gas engine fuel consumption, outlet water temperature, engine rotational speed, and system primary energy ratio.     

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.     

电动客车用余热回收型热泵的换热器优化及性能实验研究

本文针对热泵空调系统在冬季低温工况下制热能力衰减问题,通过换热器设计优化,研发出基于喷射补气的余热回收型热泵空调系统,并进行了性能实验研究.结果表明:研制的准二级压缩电动客车热泵空调系统在低温条件下具有较好的制热性能.在环境温度为-20℃,车内温度为20℃,余热量为1.8 kW的制热工况下,相比于无余热回收工况,系统制...     

大容量螺杆式无霜空气源热泵系统特性研究

本文提出一种利用螺杆式压缩机余热进行辅助解吸的无霜空气源热泵系统,建立了一套余热回收无霜空气源热泵数学模型,并实验验证了模型的准确性,分析了环境温度、相对湿度、解吸循环空气温度和质量流量等参数对系统的影响.结果表明:该系统的余热量占解吸所需总能量的比例最高可达0.61;COP受解吸循环空气温度与质量流量的影响较小,受空...     

高温压缩机变转速的复叠式热泵系统性能实验研究

为研究变转速压缩机对复叠式热泵系统的影响,本文搭建了高温压缩机变转速的复叠式热泵实验台。通过实验研究了不同运行工况下系统排气温度、中间温度、制热量、功率及COP随高温压缩机转速的变化规律。结果表明:在冷凝温度为46℃,蒸发温度为-35℃～-10℃时,压缩机运行安全可靠;在冷凝温度为46℃,蒸发温度为-25℃,高温压缩机转速从1 200 r/min增至6 000 r/min,制热量提升了129. 7%,低温压缩机功率减少43.4%; COP随高温压缩机转速的增加呈先增大后减小的趋势,存在最大COP和对应的最佳高温压缩机转速。     

双效溴化锂吸收式热泵余热回收系统数值模拟研究

溴化锂吸收式热泵机组可以有效回收利用工业和建筑中的各种形式低温余热,提高余热资源回收率,但设备参数对热泵性能影响很大.因此本文基于温度对口和梯级利用的原则,对蒸汽型双效溴化锂吸收式热泵机组内传热部件进行热力及传热分析,通过质量和能量守恒建立热泵机组数学模型,分析热网供水温度、蒸发器进口低温余热水温度和驱动热源温度这三个...     

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...     

电动汽车热泵系统低温工况的制热性能 实验研究

为研究低温时电动汽车热泵空调系统的制热性能,本文通过搭建空气源热泵空调系统实验台,实验研究了电动汽车热泵空调系统在环境温度为-10~0℃的低温工况下的制热性能,分析了压缩机转速(2000~5000 r/min)、HVAC总成进风量(300~400 m^3/h)和环境温度对该热泵系统性能的影响,最后通过推导公式,估算电动汽车在使用空调系统后的续航里程。实验结果表明:随着压缩机转速的增加,压缩机排气温度、排气压力和系统制热量均增加,而COP下降;当保持压缩机转速和环境温度不变时,HVAC总成进风量从300 m^3/h增至400 m^3/h,制热量增加约13.3%~26.0%,COP增加约0.03~0.80;在其他条件不变时,当环境温度从-10℃升至0℃,热泵空调系统的制热量增加约60.9%~71.0%,COP增加约0.51~0.63;通过公式进行计算,当环境温度为-10~0℃时,在达到相同制热量条件下,热泵空调系统可在PTC加热器的基础上使续航里程提高13.5%~20.8%。     

Investigation of an ammonia-water combined power and cooling system driven by the jacket water and exhaust gas heat of an internal combustion engine

An ammonia-water combined power and cooling system is proposed and investigated in this work, in which the waste heat contained in the jacket water and exhaust gas of an internal combustion engine can be recovered efficiently to generate power and cooling energy simultaneously. The proposed system was simulated, and its thermodynamic performance in the base case was calculated based on waste heat data from an actual gas engine with a rated power output of 300 kW. The equivalent heat-to-power efficiency of the combined system is 19.76%, and the total equivalent power output is as high as 92.86 kW. The exergy efficiency of the combined system reaches 33.69%. The effects of the turbine inlet pressure, generation pressure in the reboiler, exhaust gas temperature and cooling water temperature were studied to provide guidance for the system design. The results of an economic analysis indicate that the proposed system has good economic benefit.     

LiBr-H2O吸收式热泵的热力学分析

本文建立了LiBr-H2O吸收式热泵系统的理论模型，对热泵系统的热力学循环进行模拟计算。分析了不同操作参数（包括循环倍率、低温废水入口温度、热水入口温度、高温蒸汽入口温度）对热泵的性能系数（COP）、火积效率、?效率和熵产这4种性能评价指标的影响规律，对比了这4种性能评价标准下的系统性能变化的一致性，并探讨了作为新指标的火积效率是否适用于吸收式热泵分析。模拟结果表明：当循环倍率、热水入口温度和高温蒸汽入口温度增加时，热泵系统性能均变差，只有低温废水入口温度升高时，系统性能才逐渐提高。计算结果表明：在不同的操作参数条件下4种性能评价指标变化并不一致，有些甚至相反，但COP和火积效率的变化趋势却始终保持了很好的一致性，因此说明火积效率也可以用于吸收式热泵的性能分析。     

外绕微通道冷凝器空气源热泵热水器仿真与优化

空气源热泵热水器比燃气或电热水器更为节能。本文提出了一种外绕微通道冷凝器,可以减少制冷剂充灌量、提高换热效率、降低成本、提高安全性。建立了热泵热水器的准稳态系统模型,制冷剂侧采用稳态模型,水箱和水侧采用动态模型。通过实验证明了该系统模型可以准确地预测时变的系统功耗、水温,以及系统时均COP。通过仿真分析,发现水箱隔热层可以缩短水的加热时间、并提高系统COP约9.2%。增大冷凝器也可提升系统COP,但几乎不改变水的加热时间。最后提出了微通道冷凝器的三流程优化设计方法。     

区域水源热泵取水大温差经济性分析

对区域水源热泵供能系统在取水设计过程中的大温差小流量及小流量大温差两种运行方案的经济性进行分析。得出在采用R123冷媒主机时由于蒸发器温度降低对主机效率影响较小,特别是存在水源收费的情况,宜采用大温差运行方案;而采用R134a冷媒主机时由于蒸发器温度降低对主机效率影响相对较大,需对取水收费及能耗进行综合分析,得出最佳的运行方案。     

启停过程对空气源热泵-冷柜一体机性能影响的实验研究

空气源热泵-冷柜一体机中热泵的启停过程不仅会影响系统供热性能,还会影响冷柜性能.本文实验研究了在单独运行及联合运行工况下考虑空气源热泵的启停过程的空气源热泵-冷柜一体机的性能,分析了空气源热泵的启停次数对热泵系统和冷柜系统性能的影响.实验结果表明:相比热泵单独运行工况,空气源热泵-冷柜一体机中热泵制热量的衰减开始时间延...     

A study on the performance of multi-stage condensation heat pumpsEtude sur la performance des pompes à chaleur à condensation en plusieurs étages

In this study, computer simulation programs were developed for multi-stage condensation heat pumps and their performance was examined for CFC11, HCFC123, HCFC141b under the same condition. The results showed that the coefficient of performance (COP) of an optimized ‘non-split type’ three-stage condensation heat pump was 25–42% higher than that of a conventional single-stage heat pump. The increase in COP differed among the fluids examined. The improvement in COP was due largely to the decrease in average temperature difference between the refrigerant and water in the condensers, which resulted in a decrease in thermodynamic irreversibility. For the three-stage heat pump, the highest COP was achieved when the total condenser area was evenly distributed to the three condensers. For the two-stage heat pump, however, the optimum distribution of total condenser area varied with working fluids. For the three-stage system, splitting the condenser cooling water for the use of intermediate and high pressure subcoolers helped increase the COP further. When the individual cooling water for the intermediate and high pressure subcoolers was roughly 10% of the total condenser cooling water, the optimum COP was achieved showing an additional 11% increase in COP as compared to that of the ‘non-split type’ for the three-stage heat pump system.