一种新型吸收-压缩复合制冷循环模拟

为了对一种新型吸收-压缩复合制冷循环的性能进行模拟,使用Visual Basic语言自行编制了一个程序.该程序模拟了发生温度、蒸发温度、冷凝温度、加热量、制冷量对系统性能的影响,并将其性能与传统蒸气压缩式制冷循环作了对比.模拟结果表明:当发生温度升高时,新循环的制冷系数先增大后减小;当蒸发温度升高或加热量增大时,新循环...     

两种双级压缩制冷循环的理论分析

本文针对一级节流,两级节流,中间不完全冷却双级压缩理论制冷循环的制冷系数分别进行了理论推导,在相同制冷工况条件下,对两个循环的制冷系数大小进行了理论比较,为实际应用中循环的选择提供了理论依据,同时得出了两级节流,中间不完全冷却双级压缩理论制冷循环的特性。     

高/低压区氨水吸收/压缩复合制冷循环性能分析

针对氨水吸收/压缩复合制冷循环的方式不同,结合Schulz氨水溶液状态方程,分别对压缩机处于系统高压区和低压区两种不同的组合方式进行了理论分析计算。分析了蒸发温度、热源温度、冷却水温度和中间压力对两种组合方式下压缩机当量热耗量和热源耗热量的影响,并与单级氨水吸收制冷循环的性能系数做了比较。结果表明,压缩机当量热耗量对循环性能的影响要低于热源耗热量的影响;压缩机处于系统高压区时循环的一次用能量要明显高于压缩机处于系统的低压区;在中间压力给定时,存在一个最佳热源温度,使得氨水吸收/压缩复合制冷循环的性能系数取得最大值;随任一温度参数变化时,压缩机处于高压区时的性能系数总会出现低于单级氨水吸收循环性能系数的临界点;而压缩机处于系统低压区时循环的性能系数要高于高压区循环和单级氨水吸收循环。     

蒸气压缩式制冷的实际循环与理论循环差别的原因分析及其改进措施

实际循环由于工质存原着摩擦，涡流等阻力以及与外界的热交换，同时存在着未被理论环计入的节流损失，阻力损失和热损失，因此，实际循环与理论循环相比，实际获得的制冷量 降低，而所耗功能有所增加，所以实际循环的制冷系数小于理论循环，并了改进实际循环的技术措施。     

水制冷剂压缩式制冷机组简析

介绍水制冷剂压缩式制冷机的研究现状,并简要对比水制冷机组与R134a制冷机组的性能及成本,发现水制冷机组较R134a制冷机组在20年生命周期内的成本相比没有经济优势,最主要的原因是压缩机的成本较高。     

两种双级压缩制冷循环的理论分析

本文针对一级节流、两级节流,中间不完全冷却双级压缩理论制冷循环的制冷系数分别进行了理论推导,在相同制冷工况条件下,对两个循环的制冷系数大小进行了理论比较,为实际应用中循环的选择提供了理论依据,同时得出了两级节流、中间不完全冷却双级压缩理论制冷循环的特性。     

引射吸收制冷循环工质对性能比较

三压力引射吸收制冷循环是最新改进的吸收式制冷循环，其制冷性能明显优于传统的吸收式制冷循 。选用ＮＨ３－Ｈ２Ｏ，ＮＨ３－ＬｉＮＯ３，ＮＨ３－ＮａＳＣＮ三工质对水冷空调制冷工况的详细计算，分析了发生温度，吸收温度和冷凝温度，以及蒸发温度对性能系数和泵功的影响。     

双级压缩制冷循环最佳中间温度的计算机求解

介绍了利用制冷剂热力参数回归多项式,借助计算机求解双级压缩制冷循环的最佳中间温度及与之相应的低,高压汽缸容积比的方法,给出了多种双级压缩工况的最大制冷系统,最佳中间温度与低,高压汽缸容积比。     

单级吸附制冷循环的热力学模拟

吸附式制冷是一种既可以有效利用余热又对环境友好的制冷方式,近年来吸附式制冷的研究倍受国内外的专家学者的关注。目前,由于吸附式制冷系统的性能参数COP较低、制冷机体积庞大和吸附器结构复杂等因素限制,尚无法推广应用。为此有必要对吸附工质对的优选,性能参数的影响因素以及系统的优化组织等方面进行更深入的研究探讨。鉴于此,建立了单级吸附系统的循环热力学模型,以寻求最佳工质对并获得影响循环性能的主要因素以及评价。     

N_2O跨临界双级压缩带膨胀机制冷循环

将天然工质N_2O用于跨临界循环,建立了相应的理论模型,比较了CO_2和N_2O用于跨临界两级压缩膨胀制冷循环的性能.结果表明:N_2O用于跨临界两级蒸气压缩膨胀制冷循环中的综合性能要优于CO_2.在所选定的工况范围内,N_2O系统的C_(cop)值(性能系数)比CO_2最多提高9.6%,当气冷器出口温度越低、蒸发温度越高时,N_2O系统的C_(cop)值增加越明显;N_2O系统的最优高压压力远低于CO_2,在气体冷却器出口温度为40 ℃时,最优高压侧排气压力最多降低了16.2%;N_2O系统在排气温度、单位质量制冷量方面也较CO_2具有优势.最后提出通过降低气体冷却器出口温度来提高跨临界带膨胀机制冷循环性能和降低最优高压侧排气压力的观点.     

提高单级蒸气压缩式制冷循环制冷量的途径

在单级蒸气压缩式制冷循环中,液氨的冷凝温度随着环境温度的升高（超过30℃）而升高,从而导致制冷量大幅下降。采用液体过冷原理来解决这一实际问题,提高制冷量,满足生产上的需要。     

A novel hybrid absorption–compression refrigeration cycle

When used in traditional pool-boiling type refrigeration cycles, non-azeotropic mixed refrigerants tend to result in a reduced efficiency compared to pure refrigerants. This results from the composition shift effect, which distributes the mixture components: concentrating the more volatile component in the high pressure part of the cycle, and the less volatile component in the low pressure part. The obvious effect of this is to increase the compression ratio relative to a single component. This article investigates a way of manipulating the composition change of a refrigerant mixture, using two components of similar volatility, in order to reduce the compression ratio. Counter-current vapour–liquid contact is used in a “refrigeration column”, which is combined with a distillation column. The cycle is able to exploit heat sources below 100°C as input to the distillation column and the designer is able to optimise the consumption of compressor power and distillation heat input.     

CO2跨临界双级压缩带膨胀机制冷循环研究

摘要针对CO2制冷能效低的特点,本文建立了双级压缩带膨胀机CO2跨临界制冷循环热力学模型,在考虑实际循环中不可逆损失因素影响在基础上,对循环进行了性能系数、热力学完善度和单位制冷量炯损失等指标进行了分析计算,并与双级压缩节流膨胀CO2跨临界制冷回热循环和R22简单制冷循环进行了比较。     

Performance analysis of a combined vapor compression cycle and ejector cycle for refrigeration cogeneration

A hybrid vapor compression refrigeration (HVCR) system, which combines a vapor compression refrigeration (VCR) system and an ejector refrigeration (ER) system, was developed. The waste heat energy from the gas cooler in the VCR system is applied as driven source towards ER system.Thermodynamic investigations on the performance of the HVCR system, using CO₂ as a refrigerant, are performed with energetic and exergetic methods, and the comparative analyses with the VCR system are conducted. Comprehensive effects of key operating parameters on the system performance are also studied. The results indicate that for the same cooling capacity, the coefficient of performance (COP) of the HVCR system shows 25% higher COP and the total mechanical power consumption is reduced by 20% than that of conventional VCR system, respectively. The performance characteristics of the proposed cycle show its application potential in cooling and air-conditioning.     

对配组式双级压缩制冷系统热力循环的计算与分析

利用由多台螺杆压缩机组成的配组式双级压缩制冷系统，在高压级、低压级压缩机理论输气量之比不同的运行工况下，对其进行热力计算与分析，并对制冷量、轴功率、单位轴功率制冷量作综合的比较与分析。     

Hybrid vapor compression refrigeration system with an integrated ejector cooling cycle

A refrigeration system was developed which combines a basic vapor compression refrigeration cycle with an ejector cooling cycle. The ejector cooling cycle is driven by the waste heat from the condenser in the vapor compression refrigeration cycle. The additional cooling capacity from the ejector cycle is directly input into the evaporator of the vapor compression refrigeration cycle. The governing equations are derived based on energy and mass conservation in each component including the compressor, ejector, generator, booster and heat exchangers. The system performance is first analyzed for the on-design conditions. The results show that the COP is improved by 9.1% for R22 system. The system is then compared with a basic refrigeration system for variations of five important variables. The system analysis shows that this refrigeration system can effectively improve the COP by the ejector cycle with the refrigerant which has high compressor discharge temperature.     

应用于展示柜的CO_2蒸气压缩式制冷系统循环的分析

近年来,制冷剂对臭氧层的破坏和全球温室效应等环保问题日益突出,CO2作为理想的制冷剂开始重新得到重视。本文介绍理论的跨临界CO2蒸气压缩式制冷循环,对实验室现有CO2跨临界制冷系统进行一系列研究,并与常用制冷剂的循环进行对比,认为CO2制冷循环取代传统制冷循环应用于展示柜可大大提高制冷效率。     

Performance of compression/absorption hybrid refrigeration cycle with propane/mineral oil combination

This paper discusses the feasibility of a vapor compression/absorption hybrid refrigeration cycle for energy saving and utilization of waste heat. The cycle employs propane as a natural refrigerant and a refrigeration oil as an absorbent. A prototype of the cycle is constructed, in which a compressor and an absorption unit are combined in series. The performance of the cycle is examined both theoretically and experimentally. Although the solubility of the propane with the oil is not enough as a working pair in the absorption unit, the theoretical calculation shows that the hybrid cycle has a potential to achieve a higher performance in comparison with a simple vapor compression cycle by using the waste heat. In the experiment, the prototype cycle is operated successfully and it is found that an improvement of an absorber is necessary to achieve the good performance close to the theoretical one. The application of an AHE (absorber heat exchanger) can reduce the heat input to a generator. Further examinations on some other combinations of refrigerant/refrigeration oil and additives are desirable.