scholarly journals Effect of the Pumping-injection flow rate on Heat Transfer Characteristic of Borehole Heat Exchangers for Coupling Ground-Source Heat Pump System

2020 ◽  
Author(s):  
Jiuchen Ma ◽  
Qian Jiang ◽  
Qiuli Zhang ◽  
Yacheng Xie ◽  
Yahui Wang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Transfer Characteristic ◽  
Ground Source Heat Pump ◽  
Pump System ◽  
Heat Pump System ◽  
Injection Flow Rate ◽  
Injection Flow ◽  
Ground Source

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.

scholarly journals Effect of the Pumping-injection flow rate on Heat Transfer Characteristic of Borehole Heat Exchangers for Coupling Ground-Source Heat Pump System

2020 ◽  
Author(s):  
Jiuchen Ma ◽  
Qian Jiang ◽  
QuLi Zhang ◽  
Yacheng Xie ◽  
Yahui Wang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Transfer Characteristic ◽  
Ground Source Heat Pump ◽  
Pump System ◽  
Heat Pump System ◽  
Injection Flow Rate ◽  
Injection Flow ◽  
Ground Source

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.

scholarly journals Effect of the Pumping-injection flow rate on Heat Transfer Characteristic of Borehole Heat Exchangers for Coupling Ground-Source Heat Pump System

2020 ◽  
Author(s):  
Jiuchen Ma ◽  
Qian Jiang ◽  
Qiuli Zhang ◽  
Yacheng Xie ◽  
Yahui Wang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Transfer Characteristic ◽  
Ground Source Heat Pump ◽  
Pump System ◽  
Heat Pump System ◽  
Injection Flow Rate ◽  
Injection Flow ◽  
Ground Source

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.

Numerical Simulations of a Ground Source Heat Pump System With Pile Heat Exchangers

2014 ◽  
Vol 7 (1) ◽  
Author(s):  
Masahito Oguma ◽  
Takeshi Matsumoto ◽  
Takao Kakizaki
Keyword(s):  
Numerical Simulation ◽  
Numerical Simulations ◽  
Heat Pump ◽  
Heat Exchangers ◽  
Heat Supply ◽  
Ground Surface ◽  
Ground Source Heat Pump ◽  
Pump System ◽  
Heat Pump System ◽  
Ground Source

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.

Improvement of Transductive Support Vector Machine and its Application to Enhance Antifreeze Heat Transfer Capability in Ground Source Heat Pump System

2012 ◽  
Vol 204-208 ◽  
pp. 4349-4355
Author(s):  
Man Fu Yan ◽  
Jiu Hai Wang
Keyword(s):  
Heat Transfer ◽  
Support Vector Machine ◽  
Heat Pump ◽  
Support Vector ◽  
Ground Source Heat Pump ◽  
Pump System ◽  
Heat Pump System ◽  
Ground Source ◽  
Transfer Capability ◽  
Heat Transfer Capability

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.

Heat Transfer Analysis of Groundwater Flow for Ground Heat Exchangers in the Multi-Borehole Field of Ground Source Heat Pump under the Intermittent Operation

2014 ◽  
Vol 548-549 ◽  
pp. 595-600
Author(s):  
Can Can Zhang ◽  
Yue Jin Yu
Keyword(s):  
Groundwater Flow ◽  
Heat Pump ◽  
Heat Exchangers ◽  
Heat Transfer Analysis ◽  
Ground Source Heat Pump ◽  
Pump System ◽  
Heat Pump System ◽  
Ground Heat Exchangers ◽  
Ground Source ◽  
Thermal Interference

In order to analyze the influence of groundwater flow on ground heat exchangers with different arrangements, with a project in Nanjing the access temperature field in the multi-borehole field was simulated after the ground source heat pump system had been performed for a year. Simulation results show that the access temperature is higher in the ground surrounding the borehole than the center of the corresponding borehole, thus forming a thermal barrier surrounding the borehole. Groundwater flow helps relieve temperature imbalance owing to the imbalance of heating and cooling load. The performance of the ground heat exchangers is better in staggered arrangement than in aligned arrangement. In the borehole field, the boreholes upstream have thermal interference on those downstream. And the extent of thermal interference depends on the direction of the groundwater flow when the locations of the boreholes are fixed in the borehole field.

A Study on the Calculation Model of Rock Soil Thermal Conductivity in the Design of the Ground Source Heat Pump System

2014 ◽  
Vol 889-890 ◽  
pp. 1347-1352
Author(s):  
Hong Wen Jin ◽  
Qing Shen Fang
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Pump ◽  
Soil Layer ◽  
Heat Extraction ◽  
Ground Source Heat Pump ◽  
Soil Thermal Conductivity ◽  
Pump System ◽  
Heat Pump System ◽  
Ground Source

The rock soil thermal conductivity is the most important design parameter for the ground source heat pump system. Based on the equation applied for the heat transfer between the geothermal heat exchanger and its surrounding rock soil, a quasi-three dimensional heat conduction model showing the heat transfer inside the borehole of the U-tube was established to determine the thermal conductivity of the deep-layer rock soil. The results obtained show that the average thermal conductivity got through calculation and actual determination in a tube-embedding region of the ground source heat pump engineering were 1.895 and 1.955W/(m·°C), respectively. The soil layer, which has a great thermal conductivity and a strong integrated heat transfer capability, is suitable for the use of the ground source heat pump system with the tubes embedded underground. The soil layer, with a body temperature of 19 °C and a higher initial temperature, is suitable for the heat extraction from underground in winter. The deviation between the calculation and the determination of the average thermal conductivity in the abovementioned region was 0.06, which could meet the required precision, indicating that the results from the calculation could be used for design.

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