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

Abstract

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

Uses of dynamic simulation to predict thermal‐energy performance of buildings and districts: a review

“…Moreover, the dynamic thermal simulation of horizontally coupled earth‐liquid heat exchanger for a ground source heat pump and earth‐air heat exchanger for building ventilation was carried out in Ref . Therefore, an increase by 10 and 12% in the heat transfer through a plastic earth‐liquid heat exchanger was detected, and the earth‐liquid heat exchanger was found to be more efficient than an earth‐air heat exchanger.…”

Efficiency and area demand of multi-layer ground heat exchanger using phase change of water

“…Existing HGHX models are often created using FEM software and applying constant boundary conditions or calculating only short time periods as in [2], [3], [4]. In [5], a self-developed three-dimensional model is used, taking into account moisture transport and latent heat. The impact of soil moisture content and fluid flow rate on the heat extraction rate is presented.…”

Dynamic thermal performance of horizontal ground source heat pumps – The impact of coupled heat and moisture transfer

“…The accuracy of a numerical solution of transient transport phenomena is influenced not only by the model equations and the solution method but also by the initial conditions for soil temperature and moisture in shallow ground [23,26]. Kopecky [27] showed that the initial soil temperature was one of the most important parameters that would influence the total heat exchange through a horizontal heat exchanger for a given period.…”