电动汽车空调热泵型涡旋压缩机结构分析

为了解决电动汽车空调系统冬季采暖问题,针对冬季空调工况下压缩机单级压比增大的运行特性,以涡旋压缩机制热性能系数为热力学优化目标函数,确定了制冷剂循环系统中的最佳补气压力,优化了涡旋压缩机静涡旋盘上的中间补气口的几何位置和形状,使其具备了准双级压缩功能。将研发的热泵型电动涡旋压缩机安装于电动汽车空调系统,利用空气焓差法对系统进行了制热、制冷性能实验。实验结果表明,静涡旋盘结构优化后的热泵型电动涡旋压缩机,其制热和制冷能力可以满足5人座电动汽车司乘人员的冬季和夏季舒适性要求,并且具有较高的制热和制冷性能系数,从而提升了汽车空调系统热泵循环和制冷循环的热经济性,达到了节能的目的。     

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。     

制冷工质引射式减压原理及其技术应用

分析常规蒸气压缩制冷系统存在的不足,介绍引射式减压原理,并将其技术应用于制冷(热泵)循环系统,提出新型压缩/喷射制冷循环系统。对改进后的新型制冷系统进行热力学分析,结合制冷工质R134a的制冷工况特性,得出改进后新型制冷系统的优越性能,即提高制冷系统的能量利用效率。对制冷和空调系统节能研究具有一定的指导意义。     

可变内容积比螺杆式压缩机的性能分析

随着冷水机组、单元式空调机和水源热泵机组等产品的能效指标从名义工况EER或COP发展到IPLV或ICOP,机组的变容量或变工况性能主要取决于压缩机的变容量或变工况性能。固定内容积比的螺杆式压缩机如果在偏离设计工况下工作,效率下降,进而导致整个机组的性能下降。本文研究变内容积比螺杆式压缩机,内容积比可变化,使得压缩机内压比与外压比与工况相适应,可提升压缩机效率及机组性能。应用于冷水机组、水源热泵机组时,水源热泵机组在制冷工况时能效比可提高14.1%～35%,冷水机组的IPLV可提高7.2%左右。     

数码涡旋管道机制冷变风量运行的实验研究

对采用数码涡旋压缩机的风管送风式空调(热泵)机组在标称制冷工况下的变风量运行进行了实验研究,得出了机组制冷能力、功耗、机组效率、出风温度、排气压力、排气温度、吸气压力等参数随风量变化的关系,分析了采用数码涡旋压缩机的管道机变风量运行的特点,为风管送风式空调(热泵)机组的节能、稳定运行提供了有价值的实验支撑。     

低温热泵用涡旋压缩机性能的试验研究

制定低温热泵用涡旋压缩机试验方案,对研制的原型机进行性能测试。试验结果表明：在冷凝温度不变的情况下,随着蒸发温度的降低,原型机的制热量有所减少,但减少的速度低于普通热泵系统用涡旋压缩机;压缩机的电功率有所增加,但增加的幅度不大,且压缩机的排气温度也有所降低,故在低温工况下采用准二级压缩热泵用涡旋压缩机比采用普通热泵用涡旋压缩机可以更有效地提高空气源热泵的低温制热性能,是寒冷地区用小型空气源热泵比较适宜采用的压缩机。     

喷液冷却和喷气增焓低温热泵涡旋压缩机的对比分析

本文分析了目前低环境温度热泵用涡旋压缩机运行特性及技术要求,并对制冷剂喷液冷却和喷气增焓两种涡旋压缩机技术的特点进行了对比介绍。针对低环境温度热泵开发了两款R410A涡旋压缩机:PSH系列压缩机采用制冷剂喷液冷却技术控制压缩机排气温度,可以扩大低环境温度下的运行范围;PCH065压缩机采用制冷剂喷气增焓技术提高低环境温度工况制热量及制热性能,并通过中间排气技术提高部分负荷系统的制冷性能,内置温度保护器的应用提高了压缩机在高排气温度运行的可靠性。这些优点使得热泵系统可以在我国低环境温度区域推广使用。     

混合工质回热式节流技术在大温跨空气源热泵中的新应用

中高温热能(65～100℃)在居民生活及工业生产中有着广泛的需求。常规单级蒸气压缩式热泵从环境吸热进行中高温大温跨供热时,系统效率低,压缩机运行工况差。为实现单级蒸气压缩式热泵高效大温跨供热,本文将低温制冷领域中能够高效拓展温跨的混合工质回热式节流技术应用到大温跨供热领域,提出了混合工质回热式大温跨热泵。围绕混合工质回热式大温跨热泵所开展的系列理论及试验研究工作,揭示系统压力工况、工质组分配比以及回热方式对于大温跨热泵系统的影响机制。自主设计研制的空气源混合工质回热式大温跨热泵,供热温度达到90.38℃时,系统压比小于3,COP为2.75,效率为27.66%。     

带冷凝热回收热泵空调器的实验研究

提出了在家用空调器上安装冷凝热回收装置,该系统能够实现热泵热水器、热泵空调器和冷凝热回收功能。实验模拟不同室内外工况和不同运行模式,对整个系统供冷性能和热水供应能力进行了实验研究,并分析了不同空调与热水使用模式对整个系统的影响。最终得到了该系统制冷模式、热水器制热水模式和联合供冷与供热水模式下该系统的压缩机排气压力、压缩机吸气压力、水箱水温变化、制冷量及各个模式下系统性能系数。     

带经济器的热泵系统用涡旋压缩机的理论研究

通过对带经济器的涡旋热泵系统进行分析,建立了带经济器热泵系统用涡旋压缩机的数学模型,并根据这一模型的仿真结果分析了补气口位置对经济器系统性能的影响和补气口大小的确定方法,并给出了补气口起始的角度和补气口面积的计算式。仿真结果表明：对于实际涡旋压缩机,为了保证热泵系统在冬季低温工况下的制热性能以及夏季高温工况下的制冷性能最佳,并防止泄露,最佳开设角度可在靠近吸气腔刚刚闭合处的角度附近;设计压缩机补气口时,应考虑经济器热泵的使用环境,同时兼顾涡旋压缩机的结构特点以及加工方法等因素的限制,故应选取尽可能大的补气口,并开成圆孔。     

Application of waste heat powered absorption refrigeration system to the LNG recovery process

The recovery process of the liquefied natural gas requires low temperature cooling, which is typically provided by the vapor compression refrigeration systems. The usage of an absorption refrigeration system powered by waste heat from the electric power generating gas turbine could provide the necessary cooling at reduced overall energy consumption. In this study, a potential replacement of propane chillers with absorption refrigeration systems was theoretically analyzed. From the analysis, it was found that recovering waste heat from a 9 megawatts (MW) electricity generation process could provide 5.2 MW waste heat produced additional cooling to the LNG plant and save 1.9 MW of electricity consumption. Application of the integrated cooling, heating, and power is an excellent energy saving option for the oil and gas industry.     

Optimization of a CO2–C3H8 cascade system for refrigeration and heating

Conventional working fluids (refrigerants) are being phased out worldwide to combat with the twin menace of ozone layer depletion and global warming and natural refrigerants are fast gaining favour lately. Single stage and multi stage refrigeration systems fail to widen the gap between heat source and heat sink temperatures required in many industrial applications requiring simultaneous heating and cooling and cascaded systems appear to be the best alternative. Modest research has been done in cascaded systems based on natural refrigerants thereby offering good potential for research. In this paper, a cascaded system for simultaneous heating and cooling (refrigeration and heat pump system) with a carbon dioxide based HT cycle and propane based LT cycle for simultaneous refrigeration and heating applications has been analyzed. To facilitate prediction of optimum performance parameters, performance trends with variation in the design parameters and operating variables have been presented in this article. Relevant expressions have been developed to serve as guidelines to the user for selecting appropriate design parameters like intermediate temperature so that the system yields optimum performance. Independently developed property codes have been employed for both carbon dioxide and propane for higher accuracy.     

跨临界CO2蒸气压缩式制冷与热泵技术综述

CO2跨临界制冷循环模式因环境友好性、高温制热性、低环境温度适应性、全工况范围高效性等众多优势成为制冷领域中最热门的研究课题之一.本文分别讨论了跨临界CO2制冷或热泵技术在车辆空调、建筑采暖与热水供应、烘干产业、商超冷链等行业中的发展现状,总结并预测了跨临界CO2技术的未来发展趋势.CO2制冷技术在车辆热管理领域发展前...     

氨制冷系统节能与安全技术

氨是环保的自然制冷工质,在工业制冷领域已有一百多年的应用历史。本文从氨制冷系统的节能和安全两个研究方向进行讨论,分析了氨制冷系统节能的主要影响因素,包括冷凝形式、冷热联供、变频技术、自动化智能控制等;分析了氨制冷系统安全的主要影响因素,如低充注量技术、安全及可行性分析、安全仪表系统等。结果表明：科学合理使用以上两个方面的技术可有效提高氨制冷系统安全性和节能性。为推动氨制冷系统科学安全的使用及发展,提出需要加强氨制冷系统运维人员的专业培训教育,这对氨制冷系统安全运行至关重要。     

Prozessberechnungen für eine CO<Subscript>2</Subscript>-Anlage zur Kälte- und Wärmeerzeugung für Supermärkte. Teil 1: Weitestgehende CO<Subscript>2</Subscript>-Abkühlung durch Umgebungsluft

CO₂ processes are used in supermarkets for medium- and low-temperature refrigeration and by now even for room heating and hot tap-water preparation via heat recovery. Through systematic thermodynamic process calculations, the limits of the heat recovery from a CO₂ plant and its influence on the refrigeration process as well as the complete system are investigated for a supermarket with 100 kW medium-temperature refrigeration capacity. This investigation focuses on the energy efficiency of the heat supply by the extended CO₂ plant. By using the medium-temperature refrigeration capacity as a reference, the results for ambient temperatures between ??15?°C and?+?10?°C are applicable for other supermarket sizes as well.In part 1, a plant is investigated with a ratio between low- and medium-temperature refrigeration capacity of 0.2 and CO₂ cooling via the ambient air as far as possible. The contributions of refrigeration and heat supply are specified separately for a range of high-pressure values for sub-critical and for trans-critical operation of the CO₂ plant. Relevant data for design and operation of the CO₂ plant are made available: the supplied heating capacity (relative to the medium-temperature refrigeration capacity), the coefficients of performance of refrigeration and of combined refrigeration and heating, and the exergy efficiencies of refrigeration and of combined refrigeration and heating. With this knowledge, preferred operation parameters for the CO₂ process can be chosen depending on the ambient temperature. Moreover, the decision is prepared, whether an additional heating system is required or the heat recovery from the refrigeration plant is sufficient. In the following second part, results for limited CO₂ cooling via ambient air will be considered.     

合肥正大购物广场中央空调方案设计

中央空调系统对大型商业综合体的使用,工程造价及日后的运行费用至关重要,中央空调方案包括空调冷、热源,空调形式等,以往空调方案的比较都集中在空调冷热源及其经济性,就空调的主要形式,比如是否采用温湿度独立控制等分析较少;对空调运行可靠性分析也较少。就合肥地区一大型商业综合体的中央空调方案,包括空调形式的设计做出分析,并得出最终空调形式与建议。     

Modified Roebuck compression device for cryogenic refrigeration system of superconducting rotating machine

Cryogenic refrigeration system installed on superconducting rotor has the merit that it can eliminate cryogen transfer between rapidly revolving rotor and stationary part and, therefore, the loss generated by it. Nevertheless, such an on-board cryogenic refrigeration system has not been realized yet because of the absence of compression device that can work reliably on rapidly revolving rotor. This paper presents the idea of modified Roebuck compression device as a potential on-board compression device. Although it has the disadvantage that it requires large radial space and external cooling and heating, a modified Roebuck compression device of 14 stages with diameter of 0.80 m mounted on a rotor revolving at 3600 rpm can produce substantially high compression ratio. J-T neon refrigeration system equipped with such a compression device can produce low temperature of 30 K and be useful for cooling superconducting rotor windings made of high temperature superconductor.     

冷热互联系统研究及其能效计算准则讨论

随着节能减排的不断深入和能源效率的逐步提高,同时利用冷量和热量的冷热互联系统将得到进一步的推广应用。与传统的制冷系统和制热系统的能效计算相比,冷热互联系统能综合利用冷热两部分的能量,原来单独冷、热量的能效计算法则是否适用于新的系统需要重新考虑。本文构建了复叠机组和热泵机组互联(A系统)、以及常规制冷机组和热泵互联(B系统)两种冷热互联系统,提出了3种能效计算方式,通过具体实验操作和分析给出了3种系统的COP计算方式和结果,其中第3种计算方法综合考虑了制冷系统制冷量和热泵系统制热量作为收益,将整个系统的轴功率看作补偿能量,最为合理。     

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%.     

Analysis of thermal cycling efficiency and optimal design of heating/cooling systems for rapid heat cycle injection molding process

Rapid heat cycle molding (RHCM) is a molding process that the mold cavity is rapidly heated to a high temperature before plastic melt injection, and then cooled quickly once the cavity is completely filled. Heating/cooling efficiency and temperature uniformity of the RHCM system are two key technical parameters to ensure a high productivity and high-quality products. In this study, a numerical model to analyze the heat transfer in heating and cooling phases of RHCM was built. The effect of heating/cooling medium, layout and structure of the heating/cooling channels, mold structure, etc., on heating/cooling efficiency and temperature uniformity was studied and discussed by analyzing the thermal responses of the molding system in RHCM process. Based on the simulation results, the optimization design of the RHCM mold with hot-fluid heating was performed. Then, a new RHCM mold structure with a floating mold cavity was proposed to improve the heating/cooling efficiency and temperature uniformity. The effectiveness of this new mold structure was also verified by numerical experiments. At last, a RHCM production line with steam heating and water cooling was constructed for a thin-wall plastic part. In testing production, the molding systems can be heated and cooled rapidly with a molding cycle time of about 72 s. The production results show that the aesthetics of the molded parts was greatly enhanced and the weld mark on the plastic part’s surface was completely eliminated.