【作者】 邓帅；

【导师】 王如竹； 代彦军；

【作者基本信息】 上海交通大学 ， 动力工程及工程热物理， 2013， 博士

【摘要】 太阳能热驱动制冷技术，可转化夏季建筑物立面所接受的太阳辐射为所需冷量，在能源转换与利用层面具有合理性。然而，太阳能能流密度低且不稳定，以太阳能驱动的小型制冷机制取的冷冻水温度较高，不适宜直接输入室内末端，进行供冷。另一方面，太阳能辅助热泵进行供暖和生活热水联合供给的技术已经相对成熟，此类系统不能以高效节能的形式满足建筑制冷需求，且夏季太阳能集热环路存在过热。因此，集成太阳能制冷技术，最终形成在全年尺度内满足建筑制冷、供暖和生活热水综合需求的设备，是一个重要的研究方向。针对以上问题，本研究尝试开发一种太阳能辅助过冷的二氧化碳混合热泵（冷热兼供型），其通过太阳能驱动小型吸收机对二氧化碳机组进行过冷却，从而强化其制冷性能，使整机的冷热输出与建筑负荷更为匹配。本研究首先建立了太阳能辅助二氧化碳跨临界制冷循环的数学模型，明确了过冷却热力过程在超临界循环中的特性，比较了过冷在二氧化碳超临界循环和合成制冷剂亚临界循环中的异同，且通过稳态模拟量化节能率，明确过冷却对性能的促进。其后，从空调工况应用角度，分析了通过太阳能制冷实现过冷强化的可行性并预测了太阳能吸收式制冷与常规二氧化碳压缩式制冷两项技术结合后的整机性能。模拟结果显示，当环境温度为28oC时，过冷过程的增加可使循环COP达到4.0，相较原基本循环，制冷性能可以提升45.5%。此外，如果以太阳能吸收式制冷来实现过冷却过程，则当驱动温度为90oC时，可再生能源转化的辅助冷量占总冷量的比例为22%，当驱动温度为94oC时，该比例可升至33%。在热力学分析的基础上，开发了试验样机并分别搭建了制冷和供暖试验系统，进行了现场性能测试。实验测量了开发机组在制冷工况下，分别采用混合模式（含太阳能辅助过冷）和独立模式（普通二氧化碳制冷）的机组性能。结果显示，混合模式下，室外温度约为28.0oC时，制冷COP约为2.32。主机供暖性能测试结果显示，室外温度为10.4oC时，制热COP为2.60。因机组集成了太阳能集热和储存环路等，故影响整机性能的参数较常规热泵机组更多，特别是需考虑太阳能辐照强度等因素对机组性能的影响。故在单机性能研究的基础上，对太阳能辅助二氧化碳压缩式制冷系统进行了性能分析。研究从单一针对开发机组，扩展到包含有太阳能集热器、水箱、主机和建筑的供能系统。研究基于经过试验验证的系统模型，通过动态模拟，对影响系统性能的参数进行了分析并量化了影响程度，同时通过模拟比较了设计的制冷系统与常规制冷系统的性能。在供热工况下，太阳能辅助设备与压缩式主机的结合方式与制冷工况下不同，并非采用机内集成模式，而是作为双热源并联供给至室内末端。因此，结合供暖系统的形式，对系统重要参数，如集热器面积、水箱体积、室内负荷和控制条件等分别进行了单参数（变量）的影响程度分析。在此基础上，通过敏感性分析，确定了不同影响参数的权重，据此，选取了主要影响参数进行了以成本为目标函数的多参数同步优化模拟。并通过太阳能保证率、主机性能等性能指标对优化后的系统进行了性能分析与评价。最后，以零能耗为核心设计和评价目标，结合一栋实际建筑，讨论了以开发主机为核心的建筑能源系统实际应用。该能源系统可在全年尺度内满足90m2公寓内的制冷、采暖和生活热水需求，同时，通过太阳能光伏发电补充实现年净能耗为零。在对设计要素进行阐述的基础上，进行了能源系统整体性能分析，该分析不仅量化了含建筑在内的整体系统各部分能耗，而且比较了供需以验证设计目标。除零能耗设计指标外，对系统在舒适性等指标也进行了评价。更多还原

【Abstract】 Solar-thermal-driven cooling technology can realize a reasonable energy conversion from theexcess solar radiation on building envelope to the cooling supply in summer. However, lowenergy flux and unstable supply of solar radiation limitation technology application. Forexample, chilled water from solar-driven absorption chiller is commonly in a highertemperature range than that produced by common electricity driven chiller. Thus, it isunavailable for a direct application for indoor terminal unit due to disability indehumidification. On the other hand, solar-assisted heat pump is a high-efficiency technologywhich has already been applied in demonstration projects. However, this kind of systemcannot meet cooling demand of building in a reasonable technology solution, like what itoperates in heating mode. Meanwhile, overheat problems in the solar collector loop andstorage devices increase potential risks during the summer operation. So developing anintegration device which combines solar-assisted and heat pump technologies for acomprehensive demand of building, such as cooling, heating and domestic hot water, becomean important research direction. For this purpose, a solar-assisted sub-cooling carbon dioxideheat pump was studied in this research. The cooling supplied by solar-thermal-drivenabsorption chiller was employed to sub-cooling carbon dioxide heat pump in cooling mode. Inthis way, cooling efficiency of heat pump can be increased and meanwhile match performancebetween device and building comes into a better state.The numerical module was firstly built for CO2transcritical baseline cycle as a primarypreparing for thermodynamic analysis. The subcooling process was analyzed and the difference of subcooling concept between subcritiacal cycle of synthetic refrigerants and CO2transcritical cycle was compared. With an assistance of steady state simulation, theperformance improvement of updated cycle process was proved in terms of energy-saving.Furthermore, the feasibility of solar energy integration was discussed for enhanced subcoolingin air-conditioning application. The simulated results show that cooling COP of proposedcycle process can achieve4.0when ambient temperature is28oC which is45.5higher thanthat of baseline cycle. Moreover, when solar-driven temperature is90oC, the percentage ofassisted cooling from renewable energy to the total cooling capacity is22%, and it can reach33%when solar driven temperature is94oC.Based on the thermodynamic analysis, a prototype with the proposed cycle process wasdeveloped and on-site test systems for cooling and heating performance was built respectively.The cooling test contains two stages for hybrid mode and independent mode. The differencebetween these two modes is assisted subcooling. The test shows that cooling COP ofprototype in hybrid mode is2.32when ambient temperature is28.0oC. The heating test wascarried out as well and result shows that heating COP is2.60when ambient temperature is10.4oC.Because of integration with solar energy utilization device, amount of parameter whichinfluences the prototype performance is more than that of a conventional CO2HP. Hence,research object is transfer from the prototype to the entire system due to more externalconditions. One system module, which contains solar collector, tank, developed HP andbuilding, was estiblished for the whole year dynamic simulation. The influences from weatherconditions, indoor load and DHW load was analyzed and quantified. The comparison betweenproposed cooling system and conventional synthetic refrigerant HP was carried out as well.The integration solution for solar utilization and CO2HP in heating supply is different to thatin cooling supply. The latter solution applied the in-shell integration while the former schemechooses solar collector array and CO2HP as two thermal sources in parallel connection for heating supply. In this case, the system module was updated and performance influence fromsingle parameter, such as: solar collector area, tank volume, indoor load and controlconditions, was obtained through simulation. Based on the single parameter analysis,influence weight can be got for sensitivity analysis in order to conduct multi-parametersoptimization. The optimized system was evaluated in terms of solar fraction, deviceperformance, etc.Finally, the developed CO2HP was applied in an energy system as the core device for a netzero energy building (NZEB). The entire energy system can meet the year round demands ofcooling, heating and DHW of90m2demonstration apartment and meanwhile the net energyconsumption per year is zero. An overview about all components in NZEB, such as: passivedesign, HVAC&DHW system, indoor terminal units and renewable power system was present.The annual performance for the entire system was analyzed. Not only the consumption ofevery section in building, but also the comparison between renewable power generation andmaintenance consumption were obtained based on simulation. Besides energy balances for netzero energy aim, indoor comfort performance was also discussed in evaluation.更多还原