Study of multi-twisted-tube gas cooler for CO2 heat pump water heaters

Yang, Yingying; Li, Minxia; Wang, Kaiyang; Ma, Yixin

doi:10.1016/j.applthermaleng.2016.03.123

Cited by 32 publications

(6 citation statements)

References 11 publications

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“…热泵，不仅性能更好，而且更节能、环保和省钱。Wang 等 [42] 采用数值模拟理论研究了跨临界 CO2 螺旋槽管气体冷却器的流动和传热特性，也是通过增大传热面积来增强换热，其结构如图 9(b)所示。仿真结果表明，螺旋槽结构可以显著提高 CO2 侧的传热性能，证明了螺旋槽气体冷却器是提高跨临界 CO2 系统运行性能的有效途径。此外，Yang 等 [43] 研究了多扭曲管式换热器作为气冷器的性能，发现内管数量对热水器出水温度和气冷器压降有显著影响。Li 等 [44] 提出了一种新型仿生蜂窝型换热器，通过数值模拟证明了传热系数和综合系数分别比印刷电路板换热器高 144.6%和 40.7%，其中综…”

Section: 然而，大量经验关联式的方法仍然无法解决普遍性问题。为了精确地控制最优压力，许多学者unclassified

跨临界二氧化碳热泵研究进展与应用综述

梅申功,

刘中毅,

刘夏

2023

Journal of Clean Energy Science and Technology

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热泵技术是一种能够高效利用低品位能源的节能技术，在建筑供暖、工业余热利用、新能源等领域具有广阔的应用前景。然而，传统的热泵系统使用的制冷剂对环境有着严重的负面影响，亟需寻找一种安全、环保、高效的替代制冷剂。CO2作为一种天然制冷剂，具有良好的物理和化学特性，且非常适合作为跨临界循环的工质，在热泵技术领域显示出了巨大的优势。目前对CO2热泵的研究已经取得了一定的进展，但关于CO2热泵在不同应用场合的研究现状和发展趋势的综述较少，因此，本文系统地总结了跨临界CO2热泵在不同应用领域的最新研究成果，指出其在系统设计和运行过程中存在的压力较高，运行效率低等困难，并总结出最新的系统部件、循环结构、混合制冷剂和控制策略几方面的优化研究，结果表明了各优化方式对系统性能都有明显的提升，其中混合制冷剂是最简单的优化方式。最后，对CO2热泵技术提出展望，随着政策的扶持和技术的进步，更全面、节能和智能的CO2热泵技术将持续地发展和创新。

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Section: 然而，大量经验关联式的方法仍然无法解决普遍性问题。为了精确地控制最优压力，许多学者unclassified

跨临界二氧化碳热泵研究进展与应用综述

梅申功,

刘中毅,

刘夏

2023

Journal of Clean Energy Science and Technology

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“…The simulation results showed that the spiral groove structure can significantly improve the heat transfer performance on the CO2 side, proving that the spiral groove gas cooler is an effective way to improve the operating performance of the transcritical CO2 system. In addition, Yang et al [43] studied the performance of multi-twisted tube heat exchangers as air coolers and found that the number of inner tubes had a significant impact on the outlet water temperature of the water heater and the pressure drop of the air cooler. Li et al [44] proposed a new bionic honeycomb heat exchanger.…”

Section: Heat Exchangementioning

confidence: 99%

Research progress and applications of transcritical carbon dioxide heat pumps: A review

Mei,

Liu,

Liu

2023

Clean Energ. Sci. Tech.

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Heat pump technology is an energy-saving technology that can efficiently utilize low-grade energy. It has broad application prospects in building heating, industrial waste heat utilization, new energy and other fields. However, the refrigerants used in traditional heat pump systems have serious negative impacts on the environment, and there is an urgent need to find a safe, environmentally friendly, and efficient alternative refrigerant. As a natural refrigerant, CO2 has good physical and chemical properties and is very suitable as a working fluid in transcritical cycles, showing great advantages in the field of heat pump technology. At present, research on CO2 heat pumps has made certain progress, but there are few reviews of the research status and development trends of CO2 heat pumps in different applications. Therefore, this article systematically summarizes the latest research results of transcritical CO2 heat pumps in different application fields, pointing out the difficulties such as high pressure and low operating efficiency in system design and operation. It also summarizes the latest optimization research on system components, cycle structure, mixed refrigerants and control strategies. The results show that each optimization method can significantly improve system performance, among which mixed refrigerant is the simplest optimization method. Finally, the outlook for CO2 heat pump technology is put forward. With policy support and technological advancement, more comprehensive, energy-saving, and intelligent CO2 heat pump technology will continue to develop and innovate.

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“…Yang et al [18] analyzed a multi-twisted-tube gas cooler where a counter-current double pipe copper HX was used as the gas cooler. In their HX configuration, the inner tubes were twisted together and fitted inside a larger tube.…”

Section: Gas Coolermentioning

confidence: 99%

Recent Advances in Transcritical CO2 (R744) Heat Pump System: A Review

et al. 2019

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Heat pump (HP) is one of the most energy efficient tools for address heating and possibly cooling needs in buildings. Growing environmental concerns over conventional HP refrigerants, chlorofluorocarbons (CFCs), and hydrofluorocarbons (HFCs) have forced legislators and researchers to look for alternatives. As such, carbon dioxide (R744/CO2) has come to light due to its low global warming potential (GWP) and zero ozone depleting characteristics. Even though CO2 is environmentally benign, the performance of CO2 HP has been of concern since its inception. To improve the performance of CO2 HP, research has been playing a pivotal role in developing functional designs of heat exchangers, expansion devices, and compressors to suit the CO2 transcritical cycle. Different CO2 HP cycles coupled with auxiliary components, hybrid systems, and refrigerant mixtures along with advanced control strategies have been applied and tested. This paper presents a complete overview of the most recent developments of transcritical CO2 HPs, their components, and applications.

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Study of multi-twisted-tube gas cooler for CO2 heat pump water heaters

Cited by 32 publications

References 11 publications

跨临界二氧化碳热泵研究进展与应用综述

跨临界二氧化碳热泵研究进展与应用综述

Research progress and applications of transcritical carbon dioxide heat pumps: A review

Recent Advances in Transcritical CO2 (R744) Heat Pump System: A Review

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