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分析了CO2跨临界循环的特点,介绍了CO2工质在热泵热水器中的研究与应用发展现状,探讨了其目前所面临的问题。与传统制冷剂相比,CO2在热泵热水器中的应用具有广阔的发展前景。 相似文献
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太阳能热泵供热水系统的实验研究 总被引：21，自引：0，他引：21
一套太阳能热泵供热水系统实验装置，四季能提供５０℃热水，致热系数ＣＯＰ约达３，通过优化设计，进一步降低成本，增加供暖或空调功能，会使其更具有竞争力。 相似文献
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Heat pump dryer is a complex system because of the interaction of heat and mass transfer of the working fluids. Since the system cannot be completely close, ambient conditions (temperature and humidity) influence the performance of the system. To investigate the performance of the heat pump dryer thoroughly, simulation models of heat pump dryer components have been developed. The finite-difference method was employed in the simulation to examine the state of the working fluids and heat and mass transfer. The simulation of each component can be used to construct different system configurations the results of which are reported in Part 2. 相似文献
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空气源热泵热水器储水箱动态性能试验研究 总被引：2，自引：0，他引：2
以热泵热水器储水箱的动态性能为对象进行了试验研究。试验结果表明:在加热过程中,循环水与储水箱中的水混合较好,储水箱内水温度均匀升高,系统供热系数随循环水温度的升高而降低。放水过程中,储水箱内冷、热水分层较好,当放水流量小于800L/h时,放水效率在80%以上。放水加热过程中,放水流量在400~600L/h范围内变化时,对有效水量影响较小,循环水量和温控点位置对有效水量的影响较大,当循环水量由550L/h减小至300L/h以及温控点位置由高位降至低位时有效水量会有所增大。 相似文献
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以济南高新区某医院病房楼的热水工程为例,通过对比燃气锅炉、空气源热泵+燃气锅炉、太阳能集热器+燃气锅炉和太阳能集热器+空气源热泵等4个方案的初投资和运行费用,确定太阳能集热器+空气源热泵的生活热水系统为该项目的最优方案。 相似文献
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Heat pump dryer characteristics of four configurations, two open and two closed systems, are presented. The results are based on the simulation models developed in Part 1. Emphasis is given to the effects of ambient conditions, recirculating air ratio and evaporator bypass air ratio on the system performance. The criteria for evaluating the system performance are the specific moisture extraction rate (SMER), the moisture extraction rate (MER) and the coefficient of performance (COP). It was found that the ambient conditions and dryer efficiency play an important role in the system behaviour. Optimum performance achieved for one ambient condition cannot be assumed optimum for the others. The recirculating air ratio substantially affects the system performance while the evaporator bypass air ratio shows insignificant effect. © 1997 by John Wiley & Sons, Ltd. 相似文献
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With increase in demand for electricity at 7.5% per year, the major concern of Saudi Arabia is the amount of CO2 being emitted. The country has the potential of generating 200×106 kWh from hydrothermal sources and 120×106 terawatt hour from Enhanced Geothermal System (EGS) sources. In addition to electricity generation and desalination, the country has substantial source for direct application such as space cooling and heating, a sector that consumes 80% of the electricity generated from fossil fuels. Geothermal energy can offset easily 17 million kWh of electricity that is being used for desalination. At least a part of 181,000 Gg of CO2 emitted by conventional space cooling units can also be mitigated through ground-source heat pump technology immediately. Future development of EGS sources together with the wet geothermal systems will make the country stronger in terms of oil reserves saved and increase in exports. 相似文献
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Electric-driven heat pumps are one of the most encouraging systems that could support the raising of renewables contribution in civil sector energy consumption, especially with reference to the Countries with a high contribution of renewable energy sources in electricity generation mix. However, the evaluation of the effective energy and environmental performance of an electric heat pump meeting the space heating and cooling requests of a building has to consider several factors that affect the results. Among them great attention should be given to the variability of weather conditions in which the system operates, the changeability of the efficiency and environmental indicators of power grid. The analysis becomes more complex if the variation of these parameters is considered in terms of time and geographic location but it leads to the actual evaluation of the energy conversion system performance that is neglected by European Regulations. This paper presents an energy and environmental analysis of an electric-driven air-source heat pump providing the space heating and cooling needs of the same building located in two different geographical locations by means of a dynamic simulation performed in TRNSYS 17. The analysis is carried out considering the average and time-dependent values of the carbon dioxide emission factors for electricity and the power grid efficiency indicators evaluated by means of the real electricity generation data. In addition, the paper proposes the evaluation of the average and hourly energy and environmental parameters referred only to the electricity market zones in which the buildings are located. These indices are considered in the analysis too. The results have highlighted that the assessment based on average and high-resolution parameters, as well the evaluation based on indicators referred to electricity market zones only, could return very different outcomes leading to a significant overestimation or underestimation of the energy and environmental performance of the system based on the electric-driven heat pump. Finally, a further analysis has been carried out to determine how the results can vary considering the average value of the electric efficiency indicator suggested by Italian Regulations and that of other European Countries. 相似文献
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Heat pump dryer (HPD) performance described by computer simulation results in Parts 1 and 2 of this series of papers is here verified by experiments. An HPD designed to be operated in four configurations—two open systems and two partially closed systems—has been built. The variables in the experiments are the air flow rate, the dryer load, the ambient condition (day and night) and, for the partially closed systems, the recirculation air ratio and the evaporator bypass air ratio. The parameters used for the verification are the compressor power, the properties of air entering the dryer, the coefficient of performance, the moisture extraction rate and the specific moisture extraction rate. It is found that the experimental results agree with the simulation results within an acceptable error tolerance. In order to predict the HPD performance accurately, a fine tuning of the compressor model and the pressure drop in two-phase flow of the refrigerant are recommended. © 1997 by John Wiley & sons, Ltd. 相似文献
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以二氧化碳为研究对象,应用k-ε方法对其在水平管内与管外水成垂直交叉冷却的换热进行了分析.用FLUENT软件模拟了超临界二氧化碳在8、10 Mpa,流量为3.4、6.8 g/s,管径6 mm,壁厚1.1 mm,长400 mm的管中流动的状况;计算了平均换热系数h、Nu和Re的变化;并将10 Mpa、3.4 g/s时数值模拟得出的换热系数与实验进行了比较和分析.得出等热流密度下壁面温度的变化情况,数值模拟的换热曲线和实验测量的结果具有相同的趋势,在准临界点处都达到最大值. 相似文献
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利用太阳能辅助热泵进行干燥应用是实现碳减排的有效手段。提出了太阳能辅助的跨临界CO2 高温热泵干燥系统,并对系统的热力学特性和全生命周期能耗及排放特性模型进行分析。结果表明跨临界 CO2高温热泵干燥系统在气体冷却器出现两个窄点时,取得最大COP 及最优排气压力;跨临界 CO2 高温热泵干燥系统COP 随空气在气体冷却器出口处温度的降低显著提升,出口温度由120降低至70 ℃,COP 提升了6.32%~31.45%。相对跨临界 CO2 干燥系统和蒸汽辅助跨临界 CO2 干燥系统,太阳能+蒸汽辅助蒸汽辅助跨临界 CO2 干燥系统 的 全 生 命 周 期 一 次 能 源 消 耗 和 碳 排 放 量 最 低,分 别 为 2505.99t(标 准 煤 当 量)和5411.96t;相比蒸汽辅助跨临界 CO2 干燥系统,太阳能+蒸汽辅助跨临界 CO2 高温热泵干燥系统在使用天然气作为锅炉燃料时,气体污染物(SO2 和 NOx)和固体污染物(PM2.5和 PM10)的排放量减少了40.49%。研究结果为高效低排放高温热泵干燥系统的构建和运行提供理论参考。 相似文献
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介绍水侧经济器在冷热风型水源热泵机组中的工作原理与应用;基于ASHARE 90.1标准设计经济器,制定控制策略;基于ISO 13256—1标准测试水侧经济器的应用效果;探讨水侧经济器的适用条件、使用特点和经济效益,并对未来的应用进行展望。结果显示：低温水源进入整机水-制冷剂式冷凝器前,水侧经济器对整机回风气流预降温;标准工况下,水侧经济器有能力完全替代整机机械制冷。 相似文献