【作者】 孙婷婷；

【导师】 姚杨；

【作者基本信息】 哈尔滨工业大学 ， 供热、供燃气、通风及空调工程， 2012， 博士

【摘要】 多联式空调系统（Variable Refrigerant Flow Air Conditioning System，VRF）有着诸多公认的优点，但同时也为其自身局限性所困，很难满足严寒地区或大型、高层建筑的需求。水环热泵空调系统（Water Loop Heat Pump AirConditioning System，WLHP）是一种以回收建筑内部余热为主要特征的系统，但其存在噪声污染严重和不能按质用能等缺点。本文对传统VRF系统及WLHP系统存在的问题进行了详细分析，为解决这些问题，将两种系统的思想精髓相结合，首次提出了水环多联式热泵空调系统（Water Loop Variable Refrigerant FlowHeat Pump Air Conditioning System，WLVRF）的概念。这种新型复合式空调系统集成了VRF和WLHP的优点，同时去除了各自的缺点。为改善WLVRF系统的能源利用结构，文章提出将可再生低位热源引入系统，给出了几种WLVRF系统的衍生形式以供工程选择使用。在这些低位热源中，以空气源分布最广，使用条件最容易满足。因而，本文以空气源WLVRF系统（以ASHP作为主要加热设备）为例，对该系统的运行工况、节能性、适用性、经济性及如何进行系统方案设计和运行控制等问题进行了研究。为研究WLVRF的运行特性，本文建立了其主要设备的数学模型。利用既有文献中的实验数据对模型进行了误差验证。为实现WLVRF系统与建筑的耦合，选择了一个样本建筑，建立了建筑的负荷计算模型。利用系统设备数学模型模拟了空气源热泵（Air Source Heat Pump，ASHP）及水冷多联式空调（Water SourceVariable Refrigerant Flow Air Conditioning System，WSVRF）在WLVRF系统中的运行工况。ASHP在WLVRF系统内工作时，其出水温度远低于传统ASHP直接供热的情况，因而可以在更低的室外气温条件下安全、高效运行。对这种低温工况下ASHP的主要参数进行了仿真计算，得出ASHP的能效比随低温工况变化的关系，证明了WLVRF空调系统可以为ASHP机组提供较传统ASHP系统更加优越的运行条件，也为整个WLVRF系统的能效计算奠定了基础。对WLVRF系统中WSVRF机组的冬季工况进行了仿真，并将其与传统的空气源多联式空调系统（Air Source Variable Refrigerant Flow Air ConditioningSystem，ASVRF）的冬季工况相比较。 WLVRF系统与传统VRF相比，可以解决VRF机组性能受室外气候条件影响的问题。为更好的阐述WLVRF系统中VRF机组规模缩小给系统带来的利处，本文首次提出了VRF机组负荷重心的概念。研究了系统负荷分布不同、负荷率不同时，机组的容量负荷重心及能效负荷重心的变化情况，给出了一种方便易行，且误差在可接受范围内的负荷重心计算方法。负荷重心的提出及其计算方法的探究，可以为VRF系统设计和经济性分析提供帮助，也可以更好的定义VRF系统规模大小的概念，从而进一步说明WLVRF系统中VRF机组规模缩小给系统带来的好处。在对ASHP及WSVRF机组运行特性研究的基础上，将WLVRF系统模型与建筑模型相耦合，对WLVRF系统冬季瞬时能效比的影响因素进行了探讨，分析了冷负荷数，室外气温，环路水温等因素对系统冬季瞬时能效比的影响情况。对于一个既有建筑而言，冷负荷数和室外气温是无法人为控制的量。因而，改善WLVRF冬季瞬时能效比的唯一途径是适当改变环路水温。为此，对不同冷负荷数和室外气温时的最佳环路水温进行了考察。在此基础上，以环路保持最佳水温为控制原则，计算了WLVRF系统在北方几个代表性城市，不同内、外区建筑面积比条件下，采暖季的季节性能系数及一次能源利用率情况，以便作为北方城市大型办公建筑采用WLVRF系统供热是否节能环保的参考依据。为改善WLVRF空调系统的运行特性，亦为加速其应用推广，提出了几种有利于降低投资成本、改善系统节能性，且简单易操作的设计和控制方案，并对各方案进行了模拟验证。结果表明，利用ASHP最佳经济平衡点温度设计法可以降低系统的投资成本；利用温度双位控制法替代最佳环路水温法更有利于系统节能运行。而增多ASHP台数和扩大水环路管径的方法，对于提高系统运行的稳定性效果较好，但对系统节能贡献不大。这些结论为WLVRF系统设计和控制方案的选择提供了理论依据。最后，建立了WLVRF的费用计算模型，分析了WLVRF系统的经济性，给出了不同城市对应的适合WLVRF系统的ASHP最佳经济平衡点温度，以作为工程设计的参考。按气候分区不同，将WLVRF系统与其它常用空调系统的经济性进行了比较，以使设计者和使用者对WLVRF的经济性有更直观的认识，更加有利于WLVRF系统被快速而又理性地推广应用，使得这种集成了多种系统优点的空调方式早日有效地为暖通事业服务。更多还原

【Abstract】 Variable refrigerant flow air conditioning system (VRF) is recognized as largeamount of advantages. However, because of its own limitations, it is difficult to meetthe demands for high or large buildings in cold area. Water loop heat pump (WLHP) isan air conditioning system with heat recovery function. But it makes big noise andwastes energy quality. The defects of VRF and WLHP are analyzed here. To solve theproblems, water loop variable refrigerant flow heat pump air conditioning system(WLVRF) is proposed for the first time, which integrated advantages of both VRF andWLHP. The new system combines benefits of the two old systems and overcomes theirshortcomings. To optimize the energy structure, a few kinds of renewable energy isintroduced to WLVRF. Thus, application schemes of WLVRF with different renewableenergy are raised. Among these schemes, WLVRF with air source heat pump is the mostavailable. Therefore, air source WLVRF is studied in detail. To promote the new system,its operating property, energy efficiency, applicability, economy and methods of designand control are investigated.To study the operating property of WLVRF, mathematical modals of its mainequipments are established. Based on experimental data in reference，the accuracy ofthe modals are verified. The modal of air conditioning load for a building is also set upto couple with WLVRF system. The heating conditions of air source heat pump (ASHP)and water source variable refrigerant flow air conditioning system (WSVRF) inWLVRF are simulated based on the mathematical modals. When ASHP works in aWLVRF system, its outlet water temperature is much lower than when it works in atraditional ASHP system. So ASHP works more safely and efficiently in WLVRF. Themain parameters of ASHP in the low-temperature condition are calculated, andparametric curves are drawn. This provides a basic to the calculation of energyefficiency for the whole WLVRF system. The fact is proved that WLVRF offers a betterworking condition to ASHP than traditional ASHP system. The result lays a foundationfor the calculation of energy efficiency on WLVRF.The working conditions of WSVRF unit in WLVRF are simulated and comparedwith the working conditions of air source variable refrigerant flow air conditioningsystem (ASVRF) in winter. Seen from the result, VRF units in WLVRF are lesssensitive than ASVRF to outdoor climate. To elaborate the benefit on the deflation ofVRF units in WLVRF system, the concept of VRF loading center is proposed. Thevariation of heating capacity loading center and energy efficiency loading center withdifferent load distribution and loading rate is researched. A simple calculation method ofloading center with acceptable accuracy is given. The concept and calculation method of loading center can provide assistance in the design and economic analysis of VRFsystem. Loading center explains the scale of VRF well, and shows the profit of smallerscale for VRF unit in WLVRF system.Based on the research for the operating property of ASHP and WSVRF unit, theinfluencing factors to instantaneous energy efficiency of WLVRF in winter areinvestigated by coupling WLVRF system with the building. The influencing factors areincluding cooling load ratio, outdoor temperature and loop water temperature. It isanalyzed that how these factors influence the instantaneous energy efficiency ofWLVRF system. For a certain building, the cooling load ratio and outdoor temperaturecan never be controlled. Thus, the only way to improve the energy efficiency is to adjustwater temperature. That’s why the optimal water temperature is studied. With watertemperature maintaining the optimal value, the energy efficiency and primary energyratio for WLVRF of buildings with different inner area ratios in representative cities arecalculated. The results are given in a table. It can be regard as a standard to expect ifWLVRF is energy saving or not.To improve the characteristics and promote the use of WLVRF system, optimaldesign schemes and control methods are researched. Simulation results show that themeans to decide capacity of ASHP basing on the optimal economic balance point canreduce the initial investment; moreover, two position control method on watertemperature can slash energy consumption of the system. It stabilizes the workingcondition obviously but saves almost no energy by increasing the number of ASHP unitsand expanding diameter of water loop. So the first two methods should be selected tocreate a low energy consumption WLVRF system.Finally, the economy of WLVRF system is analyzed by establishing acomputational modal of the costs for WLVRF system. The optimal economic balancepoints of ASHP for WLVRF in cities are calculated. It can be used as a basis forengineering design. The economic comparison of WLVRF system with other commonair conditioning systems is carried out in different climate zone. The economiccomparison gives designers and users a visual impression on the economy of WLVRFsystem. It is helpful to promote the application of WLVRF system quickly and rationally.The ultimate goal is to make the WLVRF system with great advantages to contribute toHVAC career as early as possible.更多还原