变频风冷螺杆式冷水机组部分负荷性能实时优化

提出一种变频风冷螺杆式冷水机组部分负荷效率实时优化控制的方法,用于优化压缩机频率和滑阀位置的配合、风机转速及多压缩机的冷量分配。试验结果表明:该方法相比无压缩机频率和滑阀位置优化的算法,部分负荷效率提高约3%;相比无风机优化算法,部分负荷效率提高约7%;多压缩机冷量分配时,算法对效率影响较小。该方法的适用性强,可用于不同机组的配置。     

部分负荷下螺杆压缩机电机内流动与换热研究

制冷用耐氟利昂三相异步电动机广泛应用于半封闭螺杆制冷压缩机中,由压缩机吸气冷却电机。为研究冷媒对电机的冷却效果,考察冷媒流经电机后的温升及压力损失对压缩机性能的影响,确保电机安全可靠地长期运行,基于流体网络和等效热路理论建立了部分负荷下半封闭螺杆制冷压缩机用电机内流动与换热数学模型,并对其进行了试验验证,分析了不同负荷下定子绕组温度分布,冷媒温升和压降,以及压缩机功耗和容积效率等宏观性能参数的的变化趋势。研究表明,定子绕组温度和冷媒流经电机后的过热度随负荷下降而快速上升,不可逆损失增加,为保证电机绝缘可靠性和效率,应避免压缩机在过低负荷下长时间运行。     

制冷螺杆压缩机工况匹配研究

在满负荷及部分负荷,螺杆制冷压缩机具有相应的设计工况。压缩机运行工况与设计工况的匹配程度,直接影响制冷系统的COP。对工况匹配进行研究,可使螺杆压缩机获得最佳的综合性能。     

螺杆式压缩机能量调节方式的对比测试研究

滑阀调节和变频调节是当前螺杆式压缩机最常用的能量调节方式。本文对具有相同设计参数的一台螺杆式压缩机在2种能量调节方式下的性能进行测试。测试结果表明：与滑阀调节的螺杆式压缩机相比,变频调节的满负荷COP有所降低,但综合部分负荷性能（IPLV）提高约14%。     

螺杆式压缩机部分负荷性能计算方法探讨

根据螺杆式压缩机滑阀容量调节的特点,建立螺杆式压缩机部分负荷性能计算模型,并用螺杆式压缩机性能的实测数据对模型的预测精度进行验证。结果显示：模型预测的螺杆式压缩机部分负荷性能与实测数据吻合,在测试数据范围内,模型预测的最大误差小于2%。     

新型氨用半封闭螺杆压缩机的研发与应用

本文阐述了笔者所在公司在氨用单级螺杆压缩机的效率提高,型线和电机改善方面所做的研究。本文的研究对象是笔者所在公司自行研发和设计的氨用半封闭螺杆压缩机,目前,该压缩机已在制冰机机组中应用(排气量由420 m~3/h到780 m~3/h不等)。本文介绍了氨用半封闭螺杆压缩机的形式特点:采用半封闭形式;螺杆转子采用最新SRM"i"型专利螺杆转子型线;电机采用高效同步变频电机,可根据负荷变化调整电机转速。而后根据不同压缩机的实际运行结果和数据进行对比、分析和总结。结果表明,氨用半封闭螺杆压缩机在实际运用中有很大的优势,在制冷行业中有很好的应用前景。     

LU250—4．5螺杆压缩机在临涣选煤厂的应用

我厂使用最多的就是广西柳州富达的压缩机,经过一段时间的使用观察,并且同以前压缩机进行比较发现螺杆压缩机具有的可靠性能更高．使用性能更加优良,同时用来保养维护的成本也比较低,在选煤厂中使用非常适合。本文主要分析了螺杆压缩机的工作原理及主要组成．螺杆压缩机的日常维护工作,螺杆压缩机故障的分析以及处理。     

喷油工艺螺杆压缩机的特点和应用解析

喷油工艺螺杆压缩机的技术优势较为明显,在往复、离心、螺杆主流压缩机中占有一席之地。三种压缩机各有所长,喷油工艺螺杆压缩机的优势集中在中等压力复杂气体的工况中。本文针对该类型的压缩机进行特征分析,并针对其应用的工艺流程和效果进行了分析。     

螺杆制冷压缩机的噪声分析及其对策

螺杆制冷压缩机具有紧凑、高效、可靠、耐久等特点。在大中容量的范围中,有代替活塞式制冷压缩机的趋势,但在降低其噪声方面,尚须进一步研究。本文从螺杆噪声的产生与传播进行分析,并探讨其防止对策,特别对于螺杆制冷压缩机噪声源的形成及其降低噪声的声功率方面进行了分析与探讨,并指出了螺杆制冷压缩机的排气过程中,存在着回流与膨胀的喷注噪声及其改善途径。     

冷冻油对螺杆式压缩机滑阀容量调节机构可靠性的影响与分析

介绍螺杆式压缩机的滑阀容量调节机构的原理,分析冷冻油对其可靠性的影响。冷冻油的物理性能差异导致滑阀卸载力大小不同,从而影响滑阀容量调节机构的可靠性。试验结果表明：减小毛细管的孔径或增大滑阀在吸气端的受力面积可有效解决低黏度的冷冻油对滑阀容量调节机构的卸载可靠性的影响。     

电磁阀在风冷半封闭螺杆冷水机组中的应用

电磁阀是风冷螺杆冷水机组中必不可少的关键元件.本文介绍了电磁阀的原理以及其在机组中的各项作用.     

离心式冷水机组变工况运行性能分析研究

以单级离心式制冷压缩机的性能曲线为基础,分析了单级离心式冷水机组的变工况运行性能,在给定的非标准工况下,综合比较了压缩机-换热器-膨胀节流装置在各种配置下的运行性能.从数据对比,说明电子膨胀阀对于离心式冷水机组的变工况运行适应性最好,手动/半自动可调膨胀节流孔板可兼顾变工况性能与制造成本,而固定式膨胀节流装置从综合能效比来讲运行经济性较差.     

Theoretical and experimental investigation on the performance of screw refrigeration compressor under part-load conditions

Slide valve is normally employed in screw refrigeration compressor to meet the cooling capacity demanded by the load variation. A mathematical model describing the working process of screw refrigeration compressor with a slide valve assembly under part-load conditions is established based on the calculation of the effective by-pass area and radial discharge area. Experimental investigation on a screw refrigeration compressor under part-load conditions with several evaporation and condensation temperatures is also carried out. Simulation results are in good agreement with the experimental ones. With the validated model, effects of key design parameters, i.e. the installation angles of the slide valve relative to the cylinder and the slide stop length, on the working process and performance of screw refrigeration compressor have been analyzed. These results can be useful for optimum design of the slide valve assembly to improve the energy efficiency of refrigeration system with screw compressor under part-load conditions.     

Experimental evaluation of a variable effect LiBr–water absorption chiller designed for high-efficient solar cooling system

A variable effect LiBr–water absorption chiller is studied in this paper based on a real developed 50 kW prototype. The chiller is designed specifically for the high-efficient utilization of the solar power with variable temperature. It can obtain the optimized COP and cooling power under different heat source temperatures. The construction, circulation and testing system of the chiller were introduced. A typical running condition of the chiller from the starting to the steady operating was given to show the dynamic performance. Several groups of the temperatures and COPs were given to show the steady state performance. These data showed that the COP increased from 0.69 to 1.08 under generation temperature from 95 °C to 120 °C. Besides, the effects of chilled water temperature, cooling water temperature, pump frequency and opening of valve on COP and cooling power were analyzed respectively.     

Investigation of the effects of thermostatic and electronic expansion valves on the steady-state and transient performance of commercial chillers

This paper investigates the steady-state performance and transient response of a commercial fixed-speed on-off controlled chiller and presents comparative performance results obtained during operation with a thermostatic and with an electronic expansion valve. The aim was to establish the effect of the two valves on the transient and steady-state performance of the chiller and to quantify the effects of on-off cycling losses during part-load operation. The results indicate that the chiller has a very fast response during start-up and that cycling losses are very low. The thermostatic expansion valve gives a slightly faster response than the electronic expansion valve with the penalty, however, of less stable operation with larger superheat oscillations at steady-state conditions.     

小型风冷式冷热水机组的现状和发展

说明了小型风冷式冷热水机组的分类,叙述了小型风冷式冷热水机组的特点,介绍了小型风冷式冷热水机组的制冷和控制系统,阐述了小型风冷式冷热水机组性能提高途径.     

Experimental evaluation of an ejector as liquid re-circulator in a falling-film water chiller

To experimentally evaluate the performance of an ejector working as a liquid re-circulator in a horizontal-tube falling-film evaporator with R134a, experimental tests are performed using a horizontal-tube falling-film water chiller prototype. Experimental observations on intertube liquid flow pattern of tube bundle validate the feasibility of the liquid re-circulation system using a liquid–liquid ejector. The analysis results show that the influence of the motive flow rate on the entrainment ratio of the ejector is small, and the average entrainment ratio of the ejector is about 2.03. With the increase of the valve opening of the regulating valve, the evaporating capacity of the falling-film water chiller rises 4.8%, from 940.2 kW with the re-circulation ratio of one, to 985.5 kW with the re-circulation ratio of 1.135. The COP of the falling-film water chiller reaches a maximum and then drops down with the increase of the re-circulation ratio, and the optimal re-circulation ratio is 1.135.     

提高满液式冷水机组性能的途径分析

针对如何提高满液式冷水机组的性能进行阐述:分析螺杆式压缩机内容积比与等熵效率的关系对机组性能的影响,提出内容积比选择的观点;分析蒸发温度和冷凝温度对机组性能的影响,同时考虑成本问题提出控制蒸发温度与冷凝温度的设计建议;从管路设计方面提出降低管路压力损失的措施;分析满液式蒸发器回油方式对机组性能的影响,提出控制回油的实施方案。     

基于性能曲线的冷水机组配置和运行优化

在设计中引入简单有效的计算手段,对冷水机组配置和运行的优化进行节能分析是必要的,本文分析了与冷水机组节能相关的因素,介绍了常用冷水机组典型性能特征,举例分析常用冷水机组COP-PLRC-tc曲线,提出了基于性能曲线的冷水机组配置和优化运行方法,阐述了运用该方法对进行冷水机组配置和运行优化的步骤,最后为采用该方法的应用实例。     

基于外在参数的冷水机组数学模型

根据冷水机组外在参数之间的多参数非线性函数表达式,建立了描述冷水机组工作性能的个性化工程应用模型。通过相对误差检验和模拟计算得知此模型具有较高的精度,符合实际工程要求,能够可靠地应用于空调系统中冷水机组的仿真模拟。