Heat transfer of a horizontal spiral heat exchanger under groundwater advection

Li, Huai; Nagano, Katsunori; Lai, Yuanxiang

doi:10.1016/j.ijheatmasstransfer.2012.06.089

Cited by 32 publications

(12 citation statements)

References 21 publications

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“…The total heat exchange rate of cases with long pitch interval was 10-40% lower than those with short pitch intervals cases with short pitch interval. It can be inferred that use of small intervals between coils increases interference in heat transfer and leads to small heat exchange rates per pipe length [26]. For the Utype GHE, the total heat-exchange rate was the lowest among the three GHEs, but the heat exchange rate per pipe length was higher than for any other types.…”

Section: Resultsmentioning

confidence: 91%

“…Their calculation suggested the thermal superiority of spiral-coiltype GHE in comparison with line and slinky type GHEs. Li et al [26] considered thermal performance of spiral-coil-type GHE under the existence of the groundwater flow effect. However, there are a few researches for thermal efficiency evaluation among different kinds of horizontal GHEs with experimental results, and a few researches for relation between cost analysis and thermal efficiency results.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of thermal efficiency in different types of horizontal ground heat exchangers

Yoon

Lee

2015

Energy and Buildings

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Section: Resultsmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Evaluation of thermal efficiency in different types of horizontal ground heat exchangers

Yoon

Lee

2015

Energy and Buildings

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“…The results showed that the heat exchange rate per unit land area is obviously improved by using double-layer horizontal GHEs. The optimum depth of the upper layer GHE was 1.5 m when the lower layer was located at 2.0 m. Li et al [24] proposed a moving ring source model to investigate the thermal performance of a spiral GHE under groundwater flow. The experiments were also carried out to test the soil temperature variations of two different spiral GHE layouts with different groundwater velocities.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigations and Numerical Simulation of Thermal Performance of a Horizontal Slinky-Coil Ground Heat Exchanger

Zhang

Yang

et al. 2017

Sustainability

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Abstract:A model test system of horizontal slinky coil ground heat exchanger (HSCGHE) was established according to the similarity theory. A 2-D mathematical model of HSCGHE was built and experimentally validated. Experimental and numerical investigations of effects of different parameters on the thermal behavior of HSCGHE were undertaken. The results show that the heat release rate of the slinky coil and soil temperature around it increase as the inlet fluid temperature of coil increases. The soil temperature operated in intermittent mode can get a recovery, and thus the heat release rate of the coil can be improved effectively. For a given condition, reducing the coil central interval distance can increase the heat release rate of the HSCGHE, but also results in the decrease of the heat release rate per unit length of the coil. Therefore, the coil central interval distance cannot be decreased without limit. At the same time, the thermal performance of HSCGHE is related to the ground surface wind velocity. The heat release rate in the sandstone is the largest, followed by sand, the lowest for clay. Additionally, with the increase of buried depth of coil, the heat release rate increases, but the increase degree gradually becomes small. Thus, the buried depth cannot be too deep and should be determined by thermal performance, excavation cost and safety requirements.

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“…Standard models and calculation methods [10,11], new methodologies that take into account the thermal comfort [12,13], and experimental evaluation of case studies [14] are available. With regard to the ground simulation block, recently theoretical and numerical models have been developed for both the vertical borehole [15][16][17] and the horizontal loop/slinky [18,19] heat exchangers. However, the heat pump block has not been accurately addressed.…”

Section: Introductionmentioning

confidence: 99%

Impact of control schemes of a monovalent inverter-driven water-to-water heat pump with a desuperheater in continental and subtropical climates through simulation

Blanco¹,

Nagano²,

Morimoto³

2013

Applied Energy

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An application of a novel steady-state simulation of a monovalent inverter-driven water-towater heat pump with a desuperheater is presented. The simulation is capable of modeling and managing the different operation modes of the system such as combined space heating and domestic hot water, in order to provide realistic results, from which four control schemes based on two electricity tariff plans were developed. The schemes were tested on a subject low energy house for Tokyo and Sapporo, in Japan, for the coldest day of the year and for the heating season. Emphasis was given to the short-term domestic hot water storage. The results show that the application of the schemes with a flexible electricity tariff had lower cost over the scheme that used the flat rate pricing plan. Moreover, it was shown that no unique scheme was able to minimize the cost and electrical consumption for both locations. Additionally, a tradeoff between lowest cost and lowest energy consumption was identified for Sapporo. The results of this research could be applied to develop a more robust control on monovalent heat pump systems. Keywords

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Heat transfer of a horizontal spiral heat exchanger under groundwater advection

Cited by 32 publications

References 21 publications

Evaluation of thermal efficiency in different types of horizontal ground heat exchangers

Evaluation of thermal efficiency in different types of horizontal ground heat exchangers

Experimental Investigations and Numerical Simulation of Thermal Performance of a Horizontal Slinky-Coil Ground Heat Exchanger

Impact of control schemes of a monovalent inverter-driven water-to-water heat pump with a desuperheater in continental and subtropical climates through simulation

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