Analysis on influencing factors of heat transfer characteristics of vertical borehole heat exchanger under stratified soil conditions

Songqing Wang; Yuxuan Ji; Shijing He; Jing Gao; Yao Wang; Xuelong Cai

Case Studies in Thermal Engineering (Apr 2023)

Analysis on influencing factors of heat transfer characteristics of vertical borehole heat exchanger under stratified soil conditions

Songqing Wang,
Yuxuan Ji,
Shijing He,
Jing Gao,
Yao Wang,
Xuelong Cai

Affiliations

Songqing Wang: School of Civil Engineering, Northeast Forestry University, Harbin, 150040, China; Institute of Artificial Environment Control and Energy Application, Northeast Forestry University, Harbin, 150040, China; Corresponding author. School of Civil Engineering, Northeast Forestry University, Harbin, 150040, China.
Yuxuan Ji: School of Civil Engineering, Northeast Forestry University, Harbin, 150040, China; Institute of Artificial Environment Control and Energy Application, Northeast Forestry University, Harbin, 150040, China
Shijing He: School of Civil Engineering, Northeast Forestry University, Harbin, 150040, China; Institute of Artificial Environment Control and Energy Application, Northeast Forestry University, Harbin, 150040, China
Jing Gao: School of Civil Engineering, Northeast Forestry University, Harbin, 150040, China; Institute of Artificial Environment Control and Energy Application, Northeast Forestry University, Harbin, 150040, China
Yao Wang: School of Civil Engineering, Northeast Forestry University, Harbin, 150040, China; Institute of Artificial Environment Control and Energy Application, Northeast Forestry University, Harbin, 150040, China
Xuelong Cai: School of Civil Engineering, Northeast Forestry University, Harbin, 150040, China; Institute of Artificial Environment Control and Energy Application, Northeast Forestry University, Harbin, 150040, China

Journal volume & issue: Vol. 44
p. 102840

Abstract

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In recent years, factors influencing the heat transfer characteristics of the vertical borehole heat exchanger (BHE) is a hot topic in the research of the ground source heat pump (GSHP) systems. Given the complexities involved in environmental situations with respect to groundwater seepage in saturated soil and moisture migration in unsaturated soil, this paper examined the effects of various influencing factors on the heat transfer characteristics of the vertical BHE under stratified soil conditions, using theoretical research, experimental research, and numerical simulations. Subsequently, through altering five influencing factors—groundwater seepage velocity, porosity, saturation, thermal conductivity, and initial soil temperature—the working conditions of the vertical BHE under stratified soil conditions were established, and the heat transfer rate was calculated. The results showed that the weight of the influencing factors on the heat transfer characteristics of the vertical BHE had a descending order: thermal conductivity, groundwater seepage velocity, porosity, saturation, and initial soil temperature. These results can provide an important reference for further optimizing future BHE designs.

Published in Case Studies in Thermal Engineering

ISSN: 2214-157X (Online)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Technology: Engineering (General). Civil engineering (General)
Website: http://www.journals.elsevier.com/case-studies-in-thermal-engineering/

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