Experimental and numerical studies on the thermal performance of ground heat exchangers in a layered subsurface with groundwater

2020 ◽  
Vol 147 ◽  
pp. 620-629 ◽  
Author(s):  
Wenxin Li ◽  
Xiangdong Li ◽  
Yuanling Peng ◽  
Yong Wang ◽  
Jiyuan Tu
Keyword(s):  
Thermal Performance ◽  
Heat Exchangers ◽  
Ground Heat Exchangers ◽  
Numerical Studies

Performance and Economic Evaluation of Ground Heat Exchangers

2013 ◽  
Vol 838-841 ◽  
pp. 1913-1916 ◽  
Author(s):  
Seok Yoon ◽  
Nam Hyun Cho ◽  
Gyu Hyun Go ◽  
Seung Rae Lee
Keyword(s):  
Thermal Performance ◽  
Heat Exchangers ◽  
Construction Cost ◽  
Performance Tests ◽  
Operation Condition ◽  
Partially Saturated ◽  
Ground Heat Exchangers ◽  
Loop Design ◽  
Design Program ◽  
Construction Condition

This paper presents experimental study on the evaluation of thermal performance of U and W type ground heat exchangers (GHEs). These GHEs were installed in a partially saturated landfill ground which was composed of silt and clay in the runway area of Incheon International airport. Thermal performance tests (TPTs) were conducted for 100 hours under the continuous operation condition. Heat exchange rate of individual GHE was evaluated from the TPT results, and construction cost was also estimated. The required Borehole length of U and W type GHEs was calculated considering real construction condition from GLD (ground loop design) program.

scholarly journals Thermal Performance Analyses of Multiborehole Ground Heat Exchangers

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-11
Author(s):  
Wanjing Luo ◽  
Changfu Tang ◽  
Yin Feng ◽  
Pu Miao
Keyword(s):  
Thermal Performance ◽  
Heat Exchangers ◽  
Geothermal Energy ◽  
Greenhouse Gas Emission ◽  
Energy Resource ◽  
Thermal Dissipation ◽  
Uniform Heat Flux ◽  
Fluid Temperature ◽  
Cooling Mode ◽  
Ground Heat Exchangers

Geothermal energy known as a clean, renewable energy resource is widely available and reliable. Ground heat exchangers (GHEs) can assist the development of geothermal energy by reducing the capital cost and greenhouse gas emission. In this paper, a novel semianalytical method was developed to study the thermal performance of multiborehole ground heat exchangers (GHEs) with arbitrary configurations. By assuming a uniform inlet fluid temperature (UIFT), instead of uniform heat flux (UHF), the effects of thermal interference and the thermal performance difference between different boreholes can be examined. Simulation results indicate that the monthly average outlet fluid temperatures of GHEs will increase gradually while the annual cooling load of the GHEs is greater than the annual heating load. Besides, two mechanisms, the thermal dissipation and the heat storage effect, will determine the heat transfer underground, which can be further divided into four stages. Moreover, some boreholes will be malfunctioned; that is, boreholes can absorb heat from ground when the GHEs are under the cooling mode. However, as indicated by further investigations, this malfunction can be avoided by increasing borehole spacing.

Experimental thermal performance analysis of ground heat exchangers for space heating and cooling applications

2017 ◽  
Vol 113 ◽  
pp. 1168-1181 ◽  
Author(s):  
T. Sivasakthivel ◽  
Mikael Philippe ◽  
K. Murugesan ◽  
Vikas Verma ◽  
Pingfang Hu
Keyword(s):  
Performance Analysis ◽  
Thermal Performance ◽  
Heat Exchangers ◽  
Space Heating ◽  
Ground Heat Exchangers ◽  
Heating And Cooling

scholarly journals Dynamic and Static Investigation of Ground Heat Exchangers Equipped with Internal and External Fins

2020 ◽  
Vol 10 (23) ◽  
pp. 8689
Author(s):  
Atefeh Maleki Zanjani ◽  
Kobra Gharali ◽  
Armughan Al-Haq ◽  
Jatin Nathwani
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Response Times ◽  
Fluid Temperature ◽  
Physical Conditions ◽  
Ground Heat Exchangers ◽  
Numerical Studies ◽  
Operation Costs

Using fins on the inner and outer surfaces of pipes is one method to improve the heat transfer rate of ground heat exchangers (GHEs), thereby reducing the borehole depth and construction and operation costs. Results of 3D numerical studies of simple and finned U-tubes with outer and inner fins are evaluated for GHEs under similar physical conditions. Dynamic and static simulations show the effects of longitudinal fins on the thermal performance of borehole heat exchangers (BHEs) and heat transfer rate between circulating fluid and soil around pipes, while the dynamic tests include short timescale and frequency response tests. The results indicate that the maximum fluid temperature change is about 2.9% in the external finned pipe and 11.3% in the internal finned pipe compared to the finless pipe. The effects of the inlet velocity on temperature profiles, the patterns of the velocity and temperature contours due to the borehole curvature and the response times of the systems under various frequencies are also investigated in detail.

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