Numerical research on the effect of Thermal Disturbance on Soil Temperature Fields around wells of Vertically Buried Single-U-Tube Ground Heat Exchanger

2012 ◽  
Vol 7 (15) ◽  
pp. 383-391 ◽  
Author(s):  
ZhenYu Du ◽  
Yixing Zhang
Keyword(s):  
Heat Exchanger ◽  
Soil Temperature ◽  
Temperature Fields ◽  
Ground Heat Exchanger ◽  
Thermal Disturbance ◽  
Numerical Research

Simulation of Temperature Field of Soil Inside Drilling around a Vertically Buried Single-U-Tube Ground Heat Exchanger

2011 ◽  
Vol 393-395 ◽  
pp. 943-946
Author(s):  
Zhen Yu Du
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Soil Temperature ◽  
Moisture Transfer ◽  
Temperature Fields ◽  
Tube Heat Exchanger ◽  
Heat Transfer Efficiency ◽  
Ground Source ◽  
Practical Engineering ◽  
One Year

In this paper, the mathematical physical model of the heat and moisture transfer, which is about a vertical single-U-tube heat exchanger of a ground source heat pump (GSHP), is used to simulate the soil temperature fields inside drilling around a vertical single-U-tube ground source heat exchanger. The soil temperature fields inside drilling in the GSHP project running for one year are computed numerically. It shows that soil structure, cooling and heating load, cooling and heating period, and convalescence period have been determined by practical engineering conditions, the distance in the plane between drillings have a huge influence on heat transfer effect, only when the distance is designed reasonably, can it be possible to make sure normal heat transfer efficiency.

Influence of Convalescence on Soil Temperature Field around a Vertically Buried Single-U-Tube Ground Heat Exchanger

2011 ◽  
Vol 121-126 ◽  
pp. 1651-1655
Author(s):  
Zhen Yu Du ◽  
Yi Xing Zhang
Keyword(s):  
Temperature Field ◽  
Heat Exchanger ◽  
Soil Temperature ◽  
Moisture Transfer ◽  
Thermal Response ◽  
Geological Structure ◽  
Temperature Fields ◽  
Tube Heat Exchanger ◽  
Depth Direction ◽  
Single Well

The mathematical physical model of the heat and moisture transfer in the single-U-tube heat exchanger of a ground source heat pump (GSHP) is validated using observed data from the practical rock-soil thermal response test on a resident district in Taiyuan, the soil is layered according to the geological structure of an actual drill in the depth direction in this model. Inputting the dynamic design cooling and heating load of the district into the Realizable turbulent model in Fluent, the temperature fields of a single well in the GSHP project running for 1 year in 2 conditions in which convalescence is considered and not, are simulated numerically. It shows that it rather necessary to take the influence of convalescence into consideration while predicting the soil temperature field of a GSHP system running for a long term, or may not correspond to the reality and make a wrong theory guide to the practical engineering.

Numerical Research in Effects of Baffles on Heat Transfer Characteristics of a Tunnel Kiln’s Flue Gas Heat Exchanger

2014 ◽  
Vol 953-954 ◽  
pp. 911-914
Author(s):  
Jie Li
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Flue Gas ◽  
Temperature Fields ◽  
Heat Transfer Characteristics ◽  
Average Temperature ◽  
Transfer Characteristics ◽  
Air Inlet ◽  
Numerical Research ◽  
High Influence

In order to investigate effects of baffles on heat transfer characteristics of a tunnel kiln’s flue gas heat exchanger, the flow fields and temperature fields in two exchangers, one with baffles and the other without, under operative conditions, are separately simulated by using FLUENT code. According to simulation results, average temperature at the air outlet and average pressure at the air inlet of the exchanger with baffles are separately 67.2°C and 265 Pa, and those in the case of the exchanger without baffles are respectively 60.4°C and 240 Pa. Reasons why the baffles exert high influence on heat transfer characteristics of the exchanger are analyzed. On basis of the data and analysis, two conclusions are drawn: (1) Installation of baffles exerts high influence on heat transfer characteristics of the heat exchanger studied. (2) The reason why the baffles could exert such influence is that the baffles prevent much air from flowing into external zones of the baffles, so in per unit time more air exchanges heat energy with hot walls of heat exchange tubes, which are in internal zones of the baffles.

scholarly journals Externally heated geothermal bridge deck: Performance analysis of the U-tube ground heat exchanger

2020 ◽  
Vol 205 ◽  
pp. 07006
Author(s):  
Omid Habibzadeh-Bigdarvish ◽  
Xinbao Yu ◽  
Anand J. Puppala
Keyword(s):  
Heat Exchanger ◽  
Soil Temperature ◽  
Bridge Deck ◽  
Heat Extraction ◽  
Bottom Surface ◽  
Ground Heat Exchanger ◽  
Geothermal Heat ◽  
Undisturbed Soil ◽  
Existing Bridges ◽  
Winter Operation

In recent years, the geothermal heat pump de-icing system (GHDS) is introduced as a sustainable solution for bridge deck de-icing, which utilizes renewable geothermal energy. Existing GHDS designs mostly rely upon hydronic loops embedded in concrete decks. To extend the GHDS for existing bridges, a new external hydronic deck has been developed recently, which employs a hydronic pipe being attached to the bottom surface of the bridge deck. In this study, the performance of the externally heated geothermal bridge deck is investigated through winter deicing and summer recharging tests with the focus on the ground loop heat exchanger (GLHE), a key component of the GHDS. The test results show that the de-icing system was successful in maintaining the deck surface temperature above freezing in all winter tests. The soil temperature measurements indicate, the 132.5 m vertical U-tube ground heat exchanger is benefited from the undisturbed soil temperature of around 21 °C. The overall average hourly heat extraction of 0.67 kW during winter operation and average hourly heat injection of 0.69 kW during the summer operation were observed. Also, the ground thermal recharge test showed the increase of undisturbed soil temperature at 1.5 m from the geothermal borehole by 0.36 °C after 50 days of system operation.

scholarly journals Analysis of Heat Exchange Rate for Low-Depth Modular Ground Heat Exchanger through Real-Scale Experiment

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1893
Author(s):  
Kwonye Kim ◽  
Jaemin Kim ◽  
Yujin Nam ◽  
Euyjoon Lee ◽  
Eunchul Kang ◽  
...  
Keyword(s):  
Exchange Rate ◽  
Heat Exchanger ◽  
Heat Exchange ◽  
Heat Pump ◽  
Heat Extraction ◽  
Ground Heat Exchanger ◽  
Pump System ◽  
Heat Pump System ◽  
Scale Experiment ◽  
Real Scale

A ground source heat pump system is a high-performance technology used for maintaining a stable underground temperature all year-round. However, the high costs for installation, such as for boring and drilling, is a drawback that prevents the system to be rapidly introduced into the market. This study proposes a modular ground heat exchanger (GHX) that can compensate for the disadvantages (such as high-boring/drilling costs) of the conventional vertical GHX. Through a real-scale experiment, a modular GHX was manufactured and buried at a depth of 4 m below ground level; the heat exchange rate and the change in underground temperatures during the GHX operation were tracked and calculated. The average heat exchanges rate was 78.98 W/m and 88.83 W/m during heating and cooling periods, respectively; the underground temperature decreased by 1.2 °C during heat extraction and increased by 4.4 °C during heat emission, with the heat pump (HP) working. The study showed that the modular GHX is a cost-effective alternative to the vertical GHX; further research is needed for application to actual small buildings.

Parametric analysis, response surface, sensitivity analysis, and optimization of a novel spiral-double ground heat exchanger

2021 ◽  
Vol 240 ◽  
pp. 114251
Author(s):  
Ahmed A. Serageldin ◽  
Ali Radwan ◽  
Takao Katsura ◽  
Yoshitaka Sakata ◽  
Shigeyuki Nagasaka ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Heat Exchanger ◽  
Response Surface ◽  
Parametric Analysis ◽  
Ground Heat Exchanger ◽  
Surface Sensitivity
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