Field test and numerical investigation on the heat transfer characteristics and optimal design of the heat exchangers of a deep borehole ground source heat pump system

2017 ◽  
Vol 153 ◽  
pp. 603-615 ◽  
Author(s):  
Zhihua Wang ◽  
Fenghao Wang ◽  
Jun Liu ◽  
Zhenjun Ma ◽  
Ershuai Han ◽  
...  
2020 ◽  
Author(s):  
Jiuchen Ma ◽  
Qian Jiang ◽  
Qiuli Zhang ◽  
Yacheng Xie ◽  
Yahui Wang ◽  
...  

Abstract A coupling ground source heat pump system (CGSHP) is established in areas where groundwater is shallow but the seepage velocity is weak, which sets up pumping and injection wells on both sides of borehole heat exchangers (BHEs). A convection-dispersion analytical model of excess temperature in aquifer that considers groundwater forced seepage and axial effects and thermal dispersion effects is proposed. A controllable forced seepage sandbox is built by equation analysis method and similarity criteria. Through indoor test and the proposed analytical model, the correctness and accuracy of the numerical simulation software FEFLOW7.1 is verified. The influence of different pumping-injection flow rate on the heat transfer characteristic of BHEs is studied by numerical simulation. The results show that the average heat efficiency coefficient of BHEs increases and the heat influence range of downstream BHEs expands with the increasing of pumping-injection flow rate. The relation curve between Pe and the increment of heat transfer rate per unit depth of BHEs (Δ`q) is distributed as Gaussian function. The pumping-injection flow rate that makes Darcy velocity reaches 0.6×10-6~1.4×10-6 m∙s-1 in the aquifer is the best reference range for CGSHP system,so 400~600 m3∙d-1 is taken as the best pumping-injection flow rate in this paper.


2020 ◽  
Author(s):  
Jiuchen Ma ◽  
Qian Jiang ◽  
QuLi Zhang ◽  
Yacheng Xie ◽  
Yahui Wang ◽  
...  

Abstract A coupling ground source heat pump system (CGSHP) is established in areas where groundwater is shallow but the seepage velocity is weak, which sets up pumping and injection wells on both sides of borehole heat exchangers (BHEs). A convection-dispersion analytical model of excess temperature in aquifer that considers groundwater forced seepage and axial effects and thermal dispersion effects is proposed. A controllable forced seepage sandbox is built by equation analysis method and similarity criteria. Through indoor test and the proposed analytical model, the correctness and accuracy of the numerical simulation software FEFLOW7.1 is verified. The influence of different pumping-injection flow rate on the heat transfer characteristic of BHEs is studied by numerical simulation. The results show that the average heat efficiency coefficient of BHEs increases and the heat influence range of downstream BHEs expands with the increasing of pumping-injection flow rate. The relation curve between Pe and the increment of heat transfer rate per unit depth of BHEs (Δ`q) is distributed as Gaussian function. The pumping-injection flow rate that makes Darcy velocity reaches 0.6 × 10− 6~1.4 × 10− 6 m∙s− 1 in the aquifer is the best reference range for CGSHP system,so 400 ~ 600 m3∙d− 1 is taken as the best pumping-injection flow rate in this paper.


2020 ◽  
Author(s):  
Jiuchen Ma ◽  
Qian Jiang ◽  
Qiuli Zhang ◽  
Yacheng Xie ◽  
Yahui Wang ◽  
...  

Abstract A coupling ground source heat pump system (CGSHP) is established in areas where groundwater is shallow but the seepage velocity is weak, which sets up pumping and injection wells on both sides of borehole heat exchangers (BHEs). A convection-dispersion analytical model of excess temperature in aquifer that considers groundwater forced seepage and axial effects and thermal dispersion effects is proposed. A controllable forced seepage sandbox is built by equation analysis method and similarity criteria. Through indoor test and the proposed analytical model, the correctness and accuracy of the numerical simulation software FEFLOW7.1 is verified. The influence of different pumping-injection flow rate on the heat transfer characteristic of BHEs is studied by numerical simulation. The results show that the average heat efficiency coefficient of BHEs increases and the heat influence range of downstream BHEs expands with the increasing of pumping-injection flow rate. The relation curve between Pe and the increment of heat transfer rate per unit depth of BHEs (Δ‾ q ) is distributed as Gaussian function. The pumping-injection flow rate that makes Darcy velocity reaches 0.6×10 -6 ~1.4×10 -6 m∙s -1 in the aquifer is the best reference range for CGSHP system,so 400~600 m 3 ∙d -1 is taken as the best pumping-injection flow rate in this paper.


Author(s):  
Masahito Oguma ◽  
Takeshi Matsumoto ◽  
Takao Kakizaki

Feasibility of a ground source heat pump (GSHP) system with pile heat exchangers for use in houses is evaluated through a numerical simulation. This GSHP system differs from ordinary borehole-type GSHP systems because short foundation piles installed at close intervals are used as heat exchangers. It is shown that the annual heat supply provided by this GSHP system is able to satisfy the demand of a house due to the air-source exchange at ground surface.


2012 ◽  
Vol 204-208 ◽  
pp. 4349-4355
Author(s):  
Man Fu Yan ◽  
Jiu Hai Wang

To solve the problem of enhancing the heat transfer capability of antifreeze mixture in a ground source heat pump system, the existing Transductive Support Vector Machine (TSVM) model was updated into an improved TSVM model. Also, a new method of mixed antifreeze heat transfer capability classification was given in the paper by analyzing antifreeze [1] heat transfer capability of the ground source heat pump system and applying the improved TSVM model.


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