Experimental study on heat and moisture transfer in soil during soil heat charging for solar-soil source heat pump compound system

Chen, Hongbing; Ding, Hanwan; Liu, Songyu; Chen, Xilin; Wu, Wei; Wang, Qi

doi:10.1016/j.applthermaleng.2014.06.030

Cited by 31 publications

(7 citation statements)

References 8 publications

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“…34 Both the liquid and vapour water exist in the soil with a moderate MC, and moisture migration can be described by the Soret effect. 35,36 The coupled and mutual effect of heat and moisture transfer was confirmed in this study, and understanding the heat and moisture transfer characteristics had contributed to the installation and operation of GSHP systems.…”

Section: Discussionsupporting

confidence: 64%

Experimental study on heat transfer of soil with different moisture contents and seepage for ground source heat pump

Wang

Yang

et al. 2020

Indoor and Built Environment

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Geothermal energy is a renewable energy source for heating, ventilating and air-conditioning (HVAC) systems, and is leveraged by ground heat exchanger (GHE) which is a key element of ground source heat pump (GSHP). The performance of GHE is significantly affected by soil thermal properties. To explore the heat transfer characteristics of soils with different moisture contents (MC) and seepage, a well-controlled sandbox was established and a series of experiments were performed. The results demonstrated that the soil with higher MC had stronger heat dissipation capacity, especially when seepage occurred. The temperature sensor 25 cm from the sandbox-centre detected temperature changes at the 452nd, 206th and 297th min under dry, unsaturated and saturated conditions, respectively. Moreover, the dominant mode of heat transfer in soils with different MCs was conduction, and the elevated heat-releasing rate enhanced heat propagation by moisture transfer. Furthermore, the size of the thermally affected zone was proportional to the thermal diffusivity, which was 2.14 × 10−7, 5.18 × 10−7 and 4.74 × 10−7 m2/s under dry, unsaturated and saturated conditions, respectively. Overall, these results indicate that the MC is a critical factor in characterizing soil heat transfer. This study provides guidance in choosing the installation environment for GHE and confirms the importance of matching soil characteristics with the GHE load.

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Section: Discussionsupporting

confidence: 64%

Experimental study on heat transfer of soil with different moisture contents and seepage for ground source heat pump

Wang

Yang

et al. 2020

Indoor and Built Environment

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“…The higher the heat source temperature is, the larger amount of moisture migration will appear. This water migration process leads to a lower moisture content near the heat source wall 17 . Since the changes of moisture content can affect the thermal properties of unsaturated soil, the inhomogeneity of water content distribution means heat transfer process is complex in actual.…”

Section: Discussionmentioning

confidence: 99%

“…Chen et al . 17 presented an experimental study on the heat and moisture transfer in the soil for investigating heat charging and the coupled effect of heat and moisture transfer by one-dimensional soil column. Erdongan 18 reported the moisture content in soil affected the size of ground heat exchangers by changing thermal properties of soil.…”

Section: Introductionmentioning

confidence: 99%

A Simulation Model for Coupled Heat Transfer and Moisture Transport under the Action of Heat Source in Unsaturated Soils

Jin

Guo

Deng³

et al. 2018

Sci Rep

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Ground source heat pump (GSHP) system has been installed as the air-conditioning system worldwide due to it has the characteristics of high efficiency, easy access and environmental protection. Since ground heat exchanger (GHE) plays a key role in the performance of GSHPs, many models of GHE have been proposed to simulate temperature distribution around the borehole. However, most of these models depict only the heat conduction process between buried pipes and surrounding soil based on the line source model or cylindrical source model. And these models do not consider water transfer under the action of heat source, which can cause some prediction errors. The objective of this study is to provide a numerical model to simulate the spatiotemporal distribution of temperature and moisture caused by a GHE with constant temperature in unsaturated soils. The numerical model is developed by establishing two tridiagonal matrices and adopting Thomas algorithm to achieve the programming. The experiment is operated at the Taiyuan University of Technology and the comparisons between modeled and experimental data prove the high accuracy of this model. The model shows significant engineering values in designs and operations of GSHP.

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“…In additional, solar heat storage water tank would be beneficial for the stable operation of the systems [160]. In another independent research, an experiment of heat and moisture transfer during soil heat charging period was carried out for a solarsoil source heat pump compound system [161]. And testing results demonstrated an enhanced exergy efficiency of the system proposed through inputting solar energy to the evaporator [162].…”

Section: Waste Water Heat Exchangersmentioning

confidence: 97%

A review of heat pump systems for heating and cooling of buildings in China in the last decade

et al. 2015

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a b s t r a c tHeat pump technology fully shows the principle of energy recycling in terms of Heating, Ventilating and Air Conditioning (HVAC). It avoids unipolarity of energy using in the conventional HVAC system. Heat pumps use high-grade energy as a driving energy, recovering and upgrading low-grade energy for avail, like a pump. Because heat source used in HVAC usually is low temperature heat, heat pump systems adopted in HVAC will help improve heating performance coefficient. Therefore, HVAC is one of ideal users of heat pump applications, and thus high-grade energy used in HVAC can be replaced with a large number of low-temperature renewable energy. Through the heat pump technology, natural low-grade energy stored in the soil, water, air or waste heat from variant industries and daily lives, is supplied for building cooling/heating and hot water serving. Therefore, vast applications and developments of heat pump technology are presented in HVAC in China, and some progresses are achieved in the system innovation, experimental research, product development and engineering application, etc. This paper reviews the progress of researches, applications and development in the field of heat pumps for building cooling/heating in China since the 21st century.

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Experimental study on heat and moisture transfer in soil during soil heat charging for solar-soil source heat pump compound system

Cited by 31 publications

References 8 publications

Experimental study on heat transfer of soil with different moisture contents and seepage for ground source heat pump

Experimental study on heat transfer of soil with different moisture contents and seepage for ground source heat pump

A Simulation Model for Coupled Heat Transfer and Moisture Transport under the Action of Heat Source in Unsaturated Soils

A review of heat pump systems for heating and cooling of buildings in China in the last decade

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