直流变频涡旋压缩机技术特点

本文对笔者所在单位新开发的VZH67F系列直流变频涡旋压缩机运行特性及技术特点进行了介绍。VZH67F系列包括VZH052和VZH065两种型号,制冷量范围涵盖8RT~10RT,转速范围为1 000rpm~6 600rpm,主要应用于空调制冷和数据中心。VZH67F系列直流变频压缩机采用了中间排气技术用于提高部分负荷工况性能,还采用了电机过载保护,低速回油,软启动软停机,停机防反转以及除霜循环逻辑等新技术用于提高压缩机的可靠性。     

变频风机优化控制方法

针对采用变频风机和变频压缩机的风冷螺杆式冷水机组,提出一种优化制冷系统综合部分负荷性能系数的控制方法。此控制方法将风机转速与变频压缩机的转速、压缩机的供油压差、制冷系统的吸/排气压差以及压缩机的排气压力进行关联,建立一套变频风机的效率优化和可靠性优化的控制模型,并在机组的全工况IPLV和NPLV性能测试中得到验证,具有很好的应用意义。     

热泵型纯电动汽车空调系统特性

本文以R134a为制冷剂并采用三换热器设计了热泵汽车空调系统,搭建了热泵系统台架,并在制冷和制热5种工况下进行了性能测试,研究了压缩机转速、风量及环境工况对系统的影响,分析了该系统用于电动汽车的可行性。测试结果表明:温度越低,系统效率越低。-20℃压缩机转速为3 000 r/min时,系统性能系数COP约为1.5;相同工况下,系统COP随压缩机转速的增加而先增大后减小;相同工况下,系统COP随换热器风量的增加而增加。压缩机采用热泵系统,可以节约电能从而提高电动汽车续航里程。     

燃气机驱动的供热空调系统容量调节的研究

在采用冷负荷系数法计算我国典型气象地区负荷分布的基础上，对燃气机驱动的供热空调系统在不同压缩机转速下的变工况特性、变速容量调节性及其节能机理进行分析，得到了寻找根据室外温度条件对燃气机热泵系统的容量进行实时控制的压缩机转速变化规律的有效方法。     

R290电动汽车热泵空调性能实验研究

本文搭建了带水环路的R290电动汽车热泵空调实验台,研究了不同工况下系统的制冷性能和制热性能。实验结果表明:35℃常规制冷工况时,压缩机转速从1 800r/min增加6 600r/min,系统制冷量从1 789W提升至4 027W,而系统COP从3.65下降至1.82;45℃高温制冷工况时,压缩机转速从2 700 r/ min增加到4 500 r/min, 系统制冷量从1 973 W提升至3 031 W,而系统COP从2.10下降至1. 88;在-20 ℃/20 ℃低温制热工况.压缩机转速6 000 r/min时,系统制热量为2 911 W ,对应的系统COP为1.80;在-25 ℃/20 ℃低温制热工况、压缩机转3600r/min时,对应的系统制热量为1 658 W、系统COP为2.16。同时发现采用水环路的系统形式,提高了系统的安全可靠性,但与常规循环系统相比,系统性能存在-定程度的衰减,制冷量衰减300~500 W。制热量衰减200~400 W。     

变频器在油泵节能改造中的应用

本文介绍了北京ABB通用型变频器在电厂供油恒压控制系统改造中的运用。由于该系统采用了反馈恒压变频控制，既实现了系统压力恒定，恒定的供油保证了油枪喷油时供油的均匀与稳定性，从而提高了锅炉的燃烧性能与系统的稳定，又解决了供油系统在不用或少用油时因电机长期处于额定转速而产生的高额的能耗问题。经测试，改造后的系统既实现了，供油稳定、节约能源的目的，又提高供油的质量，降低了设备的运行成本。     

压缩机组安全与节能的在线监控系统研究

设计了一套以S7-300PLC为核心控制单元的监控系统,采用MCGS组态监控界面实现压缩机系统工况的实时监测和集中控制.系统采用智能PID算法获得变频工况下的最佳给定频率,无需人为设定;通过变频恒压调控机制,实现供气压力的连续、稳定调节,提高了系统的节能性和安全可靠性.     

永磁同步变频离心式冰蓄冷双工况机组运行能效分析

介绍一种高效永磁同步变频离心式冰蓄冷双工况机组,结合北京某大厦的冰蓄冷系统设计,采用逐时能耗计算方法,对分别采用常规定频离心式冷水机组、定频冰蓄冷双工况机组和永磁同步变频离心式冰蓄冷双工况机组3种空调系统技术方案进行能耗仿真模拟。结果表明,全年变频冰蓄冷比定频冰蓄冷方案节能26.4%,节省电费27.3%;变频冰蓄冷相对于非冰蓄冷方案节省电费53.3%。     

永磁变频螺杆制冷压缩机变工况运行特性试验研究

为有效提升螺杆制冷压缩机全工况运行效率,研制搭载大扭矩宽负载永磁电机的变频可变压比螺杆压缩机,针对冷水机组高权重运行工况,试验研究压缩机在不同工况不同转速下的运行特性.结果表明不同工况下压比适应性调节后,均存在使压缩机效率最高的最佳运行转速,且最优转速随着外压比的升高而增大.依据机组综合能效(IPLV)的满负荷、部分负...     

双蒸发温度的温湿分控空调机组实验研究

针对传统热湿联合处理中存在的能源浪费、热湿平衡不匹配等问题,本文利用EnergyPlus软件对上海市某住宅建筑进行全年逐时负荷模拟。根据模拟结果将温湿度独立控制技术与双蒸发温度压缩机结合在一起,搭建了基于双蒸发温度的温湿分控空调机组实验台。在进行相关理论计算的基础上对其在全年工况下运行特性进行实验研究。结果表明:将具有双蒸发温度压 缩机的空调机组用于温湿分控空调系统是可行的,机组运行可靠且满足设计要求。夏季设计工况下该机组压缩机能效比为3.5,比同冷量常规空调变频压缩机的能效比3.04提高了14.8％。同时,冬季设计工况下该机组压缩机能效比为4.3,相对于同冷量常规空调变频压缩机而言,双蒸发温度的温湿分控空调机组节能性显著。     

风冷三门冰箱能耗达到欧洲A~(++)级的改进方案

分析了风冷三门抽屉式BM产品能耗升级的改进方案。内容涉及了冰箱行业现阶段各种先进的节能方法,包括结构设计细节的改善、高性能VIP使用、先进的发泡技术等方法降低箱体热负荷;也包括使用高效压缩机、新式蒸发器、先进的控制手段等方法进行系统的优化。最终使产品达到国际领先的能耗水平。     

转子压缩机与涡旋压缩机的对比与发展

空气源热泵压缩机的性能是适合不同气候条件的热泵的关键。本文回顾了转子与涡旋压缩机的发展历程,早期房间空调器用压缩机为活塞式,后期出现了转子压缩机和涡旋压缩机,压缩机效率得以提升。转子式压缩机和涡旋式压缩机均向适应低环境温度工况的方向发展。介绍了影响这两种压缩机发展的关键技术,改进电机与压缩机的结构来提升压缩机效率,通过变压比、喷气增焓、部分负荷下调节等技术,提升了压缩机系统性能系数COP与综合部分负荷性能系数IPLV(H)。采用直流电机替代交流电机,可提高两种压缩机的电机效率和频率调节范围。通过对涡旋压缩机进行不对称涡旋盘设计,可减小噪音与泄漏量;对转子压缩机的双转子进行对称布置,增大了压缩机的容量。带排气阀的涡旋压缩机可在一定程度上实现变压缩比,而转子式压缩机有排气阀,在变工况方面具有明显的优势。两种压缩机均可采用喷气增焓技术,实现热泵低环境温度较大的压缩比。     

Experimental assessment of energy storage via variable speed compressor

In this study, usage of a variable speed refrigeration system in latent heat thermal energy storage (LHTES) system is investigated to increase energy storage efficiency. Four different compressor speed control cases are compared to obtain a constant heat transfer fluid (HTF) temperature at the inlet of the energy storage tank. These control cases are (i) control with evaporation temperature, (ii) control with ethylene glycol temperature at the outlet section of evaporator, (iii) control with suction pressure of the compressor and (iv) on/off control. By means of the experimental analysis the best control strategy is obtained as control with Case (ii), in terms of stability of inlet temperature of heat transfer fluid, variations of energy efficiency of LHTES and coefficient of performance (COP) of the system. While the Case (ii) provides the most stabile inlet temperature of HTF, Case (iv) represents the worst stability. Besides, the highest energy efficiency (99.0%), exergy efficiency (87.0%) and COP (2.05) values observed in Case (ii). Additionally, the time period to reach the set value is nearly 50 min in Case (i), Case (iii) and Case (iv) on the other hand this unstable initial time period becomes nearly 25 min for Case (ii). As a result, variable speed compressor should be controlled with Case (ii) to stabilize ethylene glycol-water solution temperatures as well as increase efficiency and COP of the system.     

Fuzzy control of the compressor speed in a refrigeration plant

In this paper, referring to a vapor compression refrigeration plant subjected to a commercially available cold store, a control algorithm, based on the fuzzy logic and able to select the most suitable compressor speed in function of the cold store air temperature, is presented. The main aim is to evaluate the energy saving obtainable when the fuzzy algorithm, which continuously regulates the compressor speed by an inverter, is employed to control the compressor refrigeration capacity instead of the classical thermostatic control, which imposes on/off cycles on the compressor that works at the nominal frequency of 50 Hz. The variation of the reciprocating compressor speed is obtained by controlling the compressor electric motor supply current frequency in the range 30–50 Hz, as it is not possible to consider values smaller than 30 Hz because of the lubrication troubles due to the splash system. In this range, two among the most suitable working fluids proposed for the R22 substitution, such as the R407C (R32/R125/R134a 23/25/52% in mass) and the R507 (R125/R143A 50/50% in mass) are tested. Comparing the compressor speed fuzzy control with the classical thermostatic control, frequently used in the cold stores and in other refrigeration systems, the experimental results show a meaningful energy saving equal even to about 13% when the R407C is used as a working fluid. In particular, to explain from the energy saving point of view the best performances of the refrigeration plant when the compressor speed varies, an exergetic analysis is realized. Besides, with regard to the inverter cost, the pay-back period determined is more than acceptable for the plant size examined.     

螺杆式制冷机组运行初始阶段油温控制分析及改进

对螺杆式制冷机组运行初始阶段的油温控制特点进行分析,发现开机时过低的冷冻油温度会使其溶解制冷剂的能力增强,从而使冷冻油黏度和润滑能力降低,加速螺杆式压缩机运动部件的机械磨损。而目前使用热力膨胀阀的油冷却系统会使供油温度不断大幅波动,并超出使用范围。采用带有加热器的油气分离器,并通过PLC控制器利用PID调节方式对电子膨胀阀开度进行自动调节,从而控制冷冻油温度,可使上述问题得到解决。     

S波段变频微波方腔干燥PET切片的研究

目的 针对聚对苯二甲酸乙二醇酯（PET）材料传统干燥方式能耗高、效率低等不足,运用微波干燥材料具有速度快、效率高、易于控制的特点,研究微波深度干燥PET技术并研制实验装置。方法 提出微波变频和变功率加热干燥技术,通过主动调整频率改善微波均匀性,结合微波变功率技术,控制PET材料温度在170～180℃,提升PET材料温度均匀性,并防止“热失控”现象的发生。结果 当干燥时间为2 h时,实现了PET深度干燥,能耗率为1.03 kW·h/kg,含水率降低至0.01%以下,达到了后续包装材料注塑加工的要求。结论 微波变频变功率加热技术适用于低含水率PET的深度干燥,比传统干燥方式能耗低并且时间短。     

Isotherms and thermodynamics for the sorption of heavy metal ions onto functionalized sporopollenin

Auto-ignition of lubricating oil working in a compressor for an air conditioner is studied experimentally. The adopted lubricating oil is an unknown mixture with multi-components and known to have flash point temperature of 170 °C. First, its auto-ignition temperature is measured 365 °C at atmospheric pressure. The lubricating oil works under high-pressure condition up to 30 atm and it is heated and cooled down repeatedly. Accordingly, auto-ignition temperatures or flammable limits of lubricating oil are required at high pressures with respect to fire safety. Because there is not a standard test method for the purpose, a new ignition-test method is proposed in this study and thereby, auto-ignition temperatures are measured over the pressure range below 30 atm. The measured temperatures range from 215 °C to 255 °C and they strongly depend on pressure of gas mixture consisting of oil vapor, nitrogen, and oxygen. They are close to flash point temperature and the lubricating oil can be hazardous when it works for high-pressure operating condition and abundant air flows into a compressor.     

宽温区空气源热泵热水机性能实验研究

本文基于一台直流调速卧式涡旋压缩机(双级压缩),结合闪蒸式中间腔补气冷却和双级节流技术,试制了一台5 HP专用于严寒、寒冷地区供暖的宽温区空气源热泵热水机(DCAHP),并在多种测试工况下对其制热性能进行了实验研究。实验结果表明:DCAHP实现了宽温区可靠制热,其名义制热量为16 548 W,制热EER为3. 0;在室外干球温度为-20. 0℃的条件下,其最大制热量可达11 278 W,制热EER为1. 6。研究发现,热力膨胀阀感温包与压缩机吸气口的距离/蒸发器单元传热管长大于7/200后,阀能力衰减剧烈,且压缩机输入功率下降了19%;若模块化蒸发器面积增加1倍,DCAHP在低温环境的制热能力可提升18%;设置冷冻油充注量精细调节装置,DCAHP的制热能效比最高可提升50%。     

Performance of double effect absorption compression cycles for air-conditioning using methanol–TEGDME and TFE–TEGDME systems as working pairs: Performances de cycles à compression absorption à double effet pour le conditionnement d'air utilisant les couples méthanol–TEGDME ou TFE–TEGDME

The organic working pairs trifluoroethanol (TFE)–tetraethyleneglycol dimethyether (TEGDME or E181) and methanol–TEGDME have some advantages over classical water–LiBr and ammonia water working pairs in absorption cycles. One of the most important features is the wide working range caused by the absence of crystallization, the low freezing temperatures of the refrigerants and the thermal stability of the mixtures at high temperatures.The performance of a double effect absorption cycle for these organic mixtures can be improved if a compression stage is introduced between the evaporator and the absorber. The coefficient of performance (COP) and primary energy ratio (PER) values in the cooling mode are significantly increased over a wide working range: the cycle can work with temperature lifts of 50ºC at 5ºC in the evaporator or it can also be powered by low grade heat. For these conditions COP and PER values are higher than 1.0 and 0.7 respectively, and the power supplied to the compressor represents up to 15% of the thermal energy supplied to the generator. As it is possible to work at high temperatures lifts, the absorber and condenser can be air cooled.     

空调水系统节能技术分析

本文从空调水系统目前存在的问题为切入点,以节能为原则,探讨和分析了空调水系统中变流量技术应用特点和节能效果,结合工程实例,通过对水泵变频调速技术在空调水系统中的应用和相应投资、运行费用的详细分析,阐明了空调水系统采用水泵变频调速技术可以带来明显的节能效果,空调制冷系统的冷冻水、冷却水变流量系统可使冷水机组在部分负荷下运行带来显著的节能效果.