Heat transfer characteristics of in-ground heat exchangers

Svec, Otto J.; Goodrich, L. E.; Palmer, J. H. L.

doi:10.1002/er.4440070307

Cited by 36 publications

(13 citation statements)

References 2 publications

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“…Thus, when the heat exchanger and soil were assumed to have the same thermal properties, the increase in the predicted heat transfer would be about 10% to 12%. The influence of the thermal resistance of the heat exchanger on heat transfer is consistent with the laboratory measurement by Svec, et al [6].…”

Section: Effect Of Interactions Between the Heat Exchanger Soil And supporting

confidence: 78%

“…For instance, the specific heat extraction would be increased to 2198 and 1829 Wh/m for the 2 nd and 11 th day of January, respectively, and 5.5 Wh/m for the last day of March. Such a seemingly large influence of the thermal properties of the heat exchanger is the consequence of neglecting the thermal resistance of surrounding soil in Equation (6). By comparison, the soil thermal resistance is included when consideration is given to the full interactions between the soil and surrounding environments using Equations (1) and (2).…”

Section: Effect Of Interactions Between the Heat Exchanger Soil And mentioning

confidence: 99%

“…Gonzalez, et al [5] measured the interactions between the soil environment and a horizontal slinky heat exchanger for a GSHP in the UK and showed that the heat exchanger modified heat and moisture transport in the soil which in turn could affect the performance of the heat pump. Svec, et al [6] performed a laboratory study of heat flow around plastic pipes buried in clay soil and developed analytical and numerical heat flow models for several configurations. It was shown that the thermal resistance of the pipe wall and the contact resistance at the pipe-soil interface substantially reduced heat flow.…”

Section: Introductionmentioning

confidence: 99%

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Dynamic thermal simulation of horizontal ground heat exchangers for renewable heating and ventilation of buildings

Gan

2017

Renewable Energy

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Gan, Guohui (2016) Dynamic thermal simulation of horizontal ground heat exchangers for renewable heating and ventilation of buildings. Renewable Energy, 103 . pp. 361-371. ISSN 1879-0682 Access from the University of Nottingham repository: http://eprints.nottingham.ac.uk/38978/1/AcceptedManuscript.pdf Copyright and reuse:The Nottingham ePrints service makes this work by researchers of the University of Nottingham available open access under the following conditions. This article is made available under the Creative Commons Attribution Non-commercial No Derivatives licence and may be reused according to the conditions of the licence. For more details see: http://creativecommons.org/licenses/by-nc-nd/2.5/ A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. Abstract: A ground heat exchanger is used to transfer thermal energy stored in soil in order to provide renewable heating, cooling and ventilation of a building. A computer program has been developed for simulation of the dynamic thermal performance of horizontally coupled earth-liquid heat exchanger for a ground source heat pump and earth-air heat exchanger for building ventilation. Neglecting the dynamic interactions between a heat exchanger and environments would significantly over predict its thermal performance and in terms of the amount of daily heat transfer the level of over-prediction could be as much as 463% for an earth-liquid heat exchanger and more than 100% for an earth-air heat exchanger. The daily heat transfer increases with soil moisture and for an earth-liquid heat exchanger the increase is between 3% and 35% with increase in moisture from 0.22 to 0.3 m 3 /m 3 depending on the magnitude of heat transfer. Heat transfer through a plastic earth-liquid heat exchanger can be increased by 10% to 12% if its thermal properties are improved to the same as surrounding soil. The increase is smaller between 2% and 4% for an earth-air heat exchanger. In addition, an earth-liquid heat exchanger is more efficient than an earth-air heat exchanger. Abbreviations HX heat exchanger EAHX earth-air heat exchanger EATV earth-air tunnel ventilation ELHX earth-liquid heat exchanger GSHP ground source heat pump

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Section: Effect Of Interactions Between the Heat Exchanger Soil And supporting

confidence: 78%

Section: Effect Of Interactions Between the Heat Exchanger Soil And mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dynamic thermal simulation of horizontal ground heat exchangers for renewable heating and ventilation of buildings

Gan

2017

Renewable Energy

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“…The installation depth and exchanger configuration did not play an important role.Šedová et al [8] performed an analysis of the influence of the ground massif, the thermal resistance (conduction) of the heat exchanger piping and the thermal resistance (convection) between the exchanger pipe wall and the flowing heat-transfer fluid. Svec et al [9] dealt with the influence of the HGHE plastic piping heat resistance. They point out the results of verification of various HGHE configurations that displayed a negative influence of the exchanger pipeline resistance, which was usually neglected in the calculations and systems modelling.…”

Section: Introductionmentioning

confidence: 99%

Changes in energy and temperature in the ground mass with horizontal heat exchangers—The energy source for heat pumps

Adamovský

Neuberger

Adamovský

2015

Energy and Buildings

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“…However, heat and moisture transfer in shallow soil surrounding a heat exchanger is neither axi-symmetric normal to the pipe nor varying uniformly along the pipe for long term operation due to the influence of daily and seasonal climatic variations and interactions between soil and the heat exchanger. For more realistic simulation, therefore, numerical solution of a three-dimensional model is required and this type of numerical heat transfer model has been developed or applied by a number of researchers [17][18][19][20][21] to predict the performance of EAHXs. Both analytical and numerical models allow parametric analysis to be performed such as air and soil properties and pipe size but the numerical model would also enable additional parameters such as non-uniform soil properties and pipe configurations to be analysed.…”

Section: Introductionmentioning

confidence: 99%

Dynamic interactions between the ground heat exchanger and environments in earth–air tunnel ventilation of buildings

Gan

2014

Energy and Buildings

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Earth-air tunnel ventilation is an energy efficient method of preheating or cooling of supply air to a building. The purposes of this study are to investigate the performance of earth-air heat exchangers under varying soil and atmosphere conditions and the interactions between the heat exchanger and environments. A computer program has been developed for simulation of the thermal performance of an earth-air heat exchanger for preheating and cooling of supply air, taking account of dynamic variations of climatic, load and soil conditions. The program solves equations for coupled heat and moisture transfer in soil with boundary conditions for convection, radiation and evaporation/condensation that vary with the climate both at the soil top surface and inside the heat exchanger. The importance of dynamic interactions between the heat exchanger, soil and atmosphere is illustrated from the comparison of the heat transfer rates through the heat exchanger. The predicted heat transfer rate varies with operating time and decreases along the passage of air in the heat exchanger. Neglecting the interactions would significantly over-predict the heat transfer rate and the amount of over-prediction increases with operating time.

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Heat transfer characteristics of in-ground heat exchangers

Cited by 36 publications

References 2 publications

Dynamic thermal simulation of horizontal ground heat exchangers for renewable heating and ventilation of buildings

Dynamic thermal simulation of horizontal ground heat exchangers for renewable heating and ventilation of buildings

Changes in energy and temperature in the ground mass with horizontal heat exchangers—The energy source for heat pumps

Dynamic interactions between the ground heat exchanger and environments in earth–air tunnel ventilation of buildings

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