Application of water loop variable refrigerant flow air-conditioning system in large-scale buildings in northern China

A water loop variable refrigerant flow（WLVRF）air-conditioning system is designed to be applied in large-scale buildings in northern China.The system is energy saving and it is an integrated system consisting of a variable refrigerant flow（VRF）air-conditioning unit,a water loop and an air source heat pump.The water loop transports energy among different regions in the buildings instead of refrigerant pipes,decreasing the scale of the VRF air-conditioning unit and improving the performance.Previous models for refrigerants and building loads are cited in this investigation.Mathematical models of major equipment and other elements of the system are established using the lumped parameter method based on the DATAFIT software and the MATLAB software.The performance of the WLVRF system is simulated.The initial investments and the running costs are calculated based on the results of market research.Finally,a contrast is carried out between the WLVRF system and the traditional VRF system.The results show that the WLVRF system has a better working condition and lower running costs than the traditional VRF system.

Entropy Assessment on Environmental Influence of Condense Heat in Recovery System in Air-Conditioning Refrigerating Machine

This paper presented an entropy evaluation method for the influences of condense heat recovery system on the environment.Aiming at the damage of the condense heat to the environment,an entropy of resource loss and an emission entropy from the condense heat recovery system in the air conditioning refrigerating machine were introduced.For the evaluation of the entropies,we developed a new algorithm for the parameter identification,called the composite influence coefficient,based on the Least Squares Support Vector Machine method.By simulation,the numerical experiments shows that the Least Squares Support Vector Machine method is one of the powerful methods for the parameter identification to compute the damage entropy of the condense heat,with the largest training error being-0.025(the relative error being-3.56%),and the biggest test error being 0.015(the relative error being 2.5%).

Design of structure and control system of semiconductor refrigeration box

In order to create low temperature environment for the valve testing,a new type of semiconductor refrigeration box based on semiconductor refrigeration chip and programmable logic controller(PLC)control system is designed.The power of the semiconductor refrigeration chip is determined by calculating the heat dissipation characteristics of the semiconductor refrigeration box.Combining natural convection heat dissipation with forced air cooling,the heat sink of semiconductor refrigeration chip is designed.In the control strategy,switch control is combined with an intelligent control strategy.Adaptive single neuron optimization algorithm based on quadratic optimization is adopted to adjust and optimize the parameters of the proportional-integral-derivative(PID)controllers in real time.Taking into account the limited hardware capabilities of the PLC,the Jacobian information in parameter adjustment is redesigned into a simplified form of identification.The actual test results of refrigeration box show good control performance.

Selection of Weather Parameters for Air-Conditioning System Design for Buildings with Long Thermal Lag

Two building factors-a longer thermal lag of more than one hour for building envelops and a lag of indoor radiation to convert into cooling load-have impact on the instantaneous heat input and instantaneous cooling load.So the two factors should be taken into account when selecting the weather parameters for air-conditioning system design.This paper developed a new statistic method for the rational selection of coincident solar irradiance,dry-bulb and wet-bulb temperatures.The method was applied to historic weather records of 25 years in Hong Kong to generate coincident design weather data.And the results show that traditional design solar irradiance,dry-bulb and wet-bulb temperatures may be significantly overestimated in many conditions,and the design weather data for the three different constructions is not kept constant.

Application of BIM technology in refrigeration station design

This paper mainly discusses the problems existing in the traditional design process of the refrigeration station and tries to solve them with BIM technology. Considering the characteristics of BIM technology, BIM design process is presented based on the traditional design process to achieve the goal of improving design quality and efficiency.

Experimental Study of Air Conditioning Unit of Evaporative Cooling Assisted Mechanical Refrigeration

The evaporative cooling,which assists the refrigeration machinery air-conditioning systems test-rig,has been designed.Its structure and working principle were described,and the performance test was conducted and analyzed.The test shows that making full use of the evaporative cooling "free cooling" in Spring and Autumn seasons can fully meet the requirements of air-conditioned comfort through the switch of the function in different seasons.Taking into account the evaporative cooling fan and pump energy consumption,compared with the traditional mechanical refrigeration system,more than 80 percent of energy can be saved,and the energy efficiency ratio of the Unit(EER)is as high as 7.63.Using the two stages of indirect evaporative cooling to pre-cool the new wind in summer,under the conditions of the same air supply temperature requirements,0.83 kg/s chilled water saved can be equivalent to the traditional mechanical refrigeration system,and when the new wind ratio up to 50 percent,more than 10 percent load was reduced in mechanical refrigeration system.The overall EER increased about 35 percent.

Optimal synthesis of compression refrigeration system using a novel MINLP approach

The optimal design of a compression refrigeration system(CRS) with multiple temperature levels is very important to chemical process industries and also represents considerable challenges in process systems engineering. In this paper, a general methodology for the optimal synthesis of the CRS, which simultaneously integrates CRS and Heat Exchanger Networks(HEN) to minimize the total compressor shaft work consumption based on an MINLP model, has been proposed. The major contribution of this method is in addressing the optimal design of refrigeration cycle with variable refrigeration temperature levels. The method can be used to make major decisions in the CRS design, such as the number of levels, temperature levels, and heat transfer duties. The performance of the developed methodology has been illustrated with a case study of an ethylene CRS in an industrial ethylene plant, and the optimal solution has been examined by rigorous simulations in Aspen Plus to verify its feasibility and consistency.

Refrigeration system synthesis based on de-redundant model by particle swarm optimization algorithm

Simultaneous optimization of refrigeration system(RS)and its heat exchanger network(HEN)leads to a large-scale non-convex mixed-integer non-linear programming(MINLP)problem.Conventionally,researchers usually adopted simplifications to confine problem scale from being too large at the cost of reducing solution space.This study established an optimization framework for the simultaneous optimization of RS and HEN.Firstly,A more comprehensive and compact model was developed to guarantee a relatively complete solution space while reducing model scale as well as its solving difficulty.In this model,a tandem arrangement of connecting sub-coolers and expansion valves was considered in the superstructure;and the pressure/temperature levels were optimized as continuous variables.On this basis,we proposed a"two-step transformation method"to equivalently transform the cross-level structure into a no n-cross-level structu re,and the de-redundant superstructu re was established with ensuring comprehensiveness and rigor.Furthermore,the MINLP model was developed and solved by Particle Swarm Optimization algorithm.Finally,our methodology was validated to get better optimal results with less CPU time in two case studies,an ethylene RS in an existing plant and a reported propylene RS.

涡轮压缩膨胀机的设计与性能分析

随着人们环境保护意识的加强,天然工质制冷剂重新受到研究人员的关注。空气是一种安全且对环境绝对友好的天然制冷剂,未来,压缩空气制冷循环有望成为传统蒸气压缩制冷循环的潜在替代品。压缩膨胀机作为压缩空气制冷的核心部件,其工作效率对机组性能有直接影响。为了设计出能够配合膨胀机高效工作的离心压缩机,需要对传统的设计方法进行一些修正。本文将质量、动量、能量守恒与射流尾迹区理论相结合,并将传统的离心压缩机相关参数推广到较低压力的范围中,提出了一种与现有的涡轮膨胀机相匹配的离心压缩机几何参数的设计方法。使用该方法为现有的膨胀机设计了对应的离心压缩机,并利用其他学者分析过的离心压缩机模型对该方法进行验证,利用计算流体力学方法(CFD)对压缩膨胀机变工况下的工作性能及对膨胀功的利用率进行模拟分析。按本方法设计的离心压缩机在设计工况下能够以高于92%的效率利用膨胀机的输出功。在变工况条件下能够以高于88%的效率利用膨胀机的输出功,并且在设计质量流量附近能够顺利运行。

国产冰箱的迭代图谱及设计趋势研究

通过对于国产冰箱的案例搜集与分析,依据政策变化将其发展历史划分为四个阶段,从设计学角度构建起国产冰箱的迭代图谱。基于社会学视角剖析中国不同历史时期人民的生活方式,探索国产冰箱设计发展演变中的内在逻辑,通过分析迭代图谱与社会生活变迁的相互关系,以期论证以生活方式预测家电产品设计趋势的潜在可能性。基于以上研究,结合当前社会热点和人民生活方式特点,提出了国产冰箱设计的两大发展趋势:产品使用场景的跨越与人工智能技术的深度融合,旨在为未来的冰箱设计提供启示与借鉴。

新能源冷藏车制冷机锁扣注射模设计

针对10%碳纤维改性PEEK材料的新能源冷藏车制冷机锁扣,设计了1模2腔三板注射模,模具浇注系统使用点浇口,采用4个定模滑块先抽芯机构实现成型塑件部分特征的脱模,其中1个为斜向抽芯机构,3个为直线型抽芯机构。抽芯机构依靠开模动力驱动锁紧块拉动滑块抽芯和锁紧,动作可靠且效率高,保证了塑件的成型效率及成型品质。

基于改进的粒子群优化算法的暖通空调制冷机房BIM自动优化布置方法

采用结合Revit API和MATLAB的编程模式,对Revit平台进行了有效的二次开发,从而实现了暖通空调制冷机房设备的自动化布置设计,不仅有效地实现了设备布置方案的自动生成,还支持了布置方案的预览与验证,显著提高了设计效率和准确性。该研究的创新之处在于成功将粒子群优化算法与BIM技术相结合,为暖通空调系统的自动化设计提供了新的视角,并验证了BIM在暖通空调领域正向设计中的应用潜力。

带气液调配蒸发器空气源热泵热水器的实验研究

气液调配蒸发器通过调整干度和质量流速实现传热性能提升。分别将两个管程布置为4-2-4-6-4(蒸发器1)和5-4-3-4-4(蒸发器2)的气液调配蒸发器用于热泵热水器中(分别为系统A和系统B)进行实验,并进行了对比研究。结果表明:相比于蒸发器1,蒸发器2制冷剂分布更均匀,且蒸发器侧压降减小了10.91%。在名义工况下,相比于系统A,系统B制热量减少1.69%,功率也减少1.45%,两个系统COP基本相同。系统B的排气压力比系统A小26.35~84.78 kPa,更有利于压缩机的安全运行;在不同的环境温度下,系统B的压缩机功耗均小于系统A,当环境温度为30℃时,系统B的性能比系统A提高了2.1%。

某系列直升机蒸发循环制冷系统压力故障排查及处理

结合某系列直升机蒸发循环制冷系统的构造和工作原理,分析了其使用过程中的常见故障,对与制冷剂压力相关的故障给出了相应的排查方法,并给出了制冷剂渗漏检测和加注等后续处理措施和方法,提出了制冷系统维护及设计建议。

基于可供性理论与FAHP的家用智能冰箱设计研究

为解决家用智能冰箱功能单一,外形同质化严重,无法满足现今家庭的多元化需求的问题,提出可供性理论与三角模糊层次分析法结合的产品设计方法。首先,采用机会洞察的方式确定产品应用场景,通过用户体验地图对居家使用场景进行分析与描绘,捕捉家用冰箱用户的原始需求。其次,以功能、行为、认知、感官四类可供性要素为设计框架,划分用户需求集合,并将原始用户需求转化为设计要素。再次,利用三角模糊数构建模糊判断矩阵并计算各层元素的综合权重,筛选核心设计要素。最后,以核心设计要素为基础,将其转化为契合用户需求的家用冰箱设计方案。通过场景分析、可供性理论、三角模糊层次分析法(FAHP)的集成运用,可厘清用户需求动线、有效分类层级信息,捕捉设计重点,为同类产品创新设计提供参考。

平嵌电冰箱标准的制定研究

基于目前家居一体化发展趋势,本文对比现有嵌装冰箱的安装和使用方式,分析嵌装冰箱的市场现状和存在的相关问题,对平嵌电冰箱差异化的安装和使用方式进行了阐述,并对现有嵌装冰箱相关标准进行解读与分析,在冰箱家居融合、专业设计、专业安装方面,对平嵌电冰箱标准的制定提出了对策和建议,最后总结了平嵌电冰箱及其标准对行业发展的重要推动作用。

主被动双模式冷藏集装箱设计及箱内环境特性分析

[目的]提高冷链运输装备分析主被动双模式对冷链集装箱箱内环境分布特性的影响。[方法]提出一种集制冷机组、纤维送风管道、相变蓄冷板于一体的主被动双模式冷藏集装箱(控温区间为-1~10℃),该系统利用被动释冷模式运行,箱内空气温度>10℃时切换为主动释冷模式运行,对箱体数值进行模拟研究,并分析箱内环境分布特性。[结果]主被动双模式箱内速度分布均匀,气流可送达箱内各处;主动释冷模式温度分布均匀,箱内温度梯度较小,最大温差仅为0.3℃,被动释冷模式箱内温度梯度略大,且温度不均匀性高于主动释冷模式;与单独采用被动制冷模式相比,主被动双模式可有效保证10℃以下温区长时运输,有利于大多数新鲜货物冷藏运输。[结论]主被动双模式冷链集装箱设计具有较大的能源优化潜力,且流场均匀、温度稳定并具有较强的实用价值。

热电制冷器散热的有限元仿真分析方法

随着热电制冷技术的推广应用,更多的设备开始应用热电制冷器作为散热器件,但是含有热电制冷器的散热系统的有限元仿真方法并没有被工程设计人员熟悉。为使设计人员在设计前期考虑到热电制冷器的作用,并进行合理有效的有限元热仿真分析用于指导散热系统的设计,研究了含热电制冷器的散热系统在有限元热仿真中的参数设置、分析步骤、分析方法,并与试验进行对比验证。同时还探索了热电制冷器的简易分析方法,对简化分析方法也做了验证分析。总结出了热电制冷器在有限元热仿真分析中的分析方法、分析步骤等,给带有热电制冷器的散热系统仿真提供了可靠且简便的仿真分析方法。

基于无意识行为的冰箱设计研究

无意识设计理念是基于用户的使用行为,以提升用户的情感交互需求为目的,应用于产品设计的过程中。文章以冰箱产品为例,基于用户的行为习惯,洞察用户接近本能、未加思索而做出的无意识行为,分析并研究用户使用冰箱过程中的行为特征,提出基于无意识行为的冰箱设计策略。以期为关注行为的产品设计提供一定的参考。

暖通空调工程制冷系统管道设计及施工技术

随着建筑行业的不断发展,暖通空调工程在提高建筑舒适度和节能方面发挥着越来越重要的作用。其中,制冷系统作为暖通空调工程的核心部分,其管道设计与施工技术直接影响到整个系统的运行效率和可靠性。论文基于实际工作经验,探讨了制冷系统管道设计的基本原则和施工技术的关键点,旨在优化设计与施工流程,提升系统性能。研究结果表明,通过合理的管道布局、精确的材料选择和严格的施工管理,可以显著提高制冷系统的效率和稳定性。