A study on heat transfer characteristics and pile group influence of enhanced heat transfer energy piles

2019 ◽  
Vol 24 ◽  
pp. 100768 ◽  
Author(s):  
Ling-peng Kong ◽  
Lan Qiao ◽  
Yun-yang Xiao ◽  
Qing-wen Li
2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Qingwen Li ◽  
Lu Chen ◽  
Haotian Ma ◽  
Chung-Ho Huang

The latest research on energy piles demonstrates that most scholars are focusing their attention on optimization by designing more efficient heat exchanger coils, analyzing the heat pump matching parameters, and so on. However, after more than 20 years of development, these traditional methods for improving the heat transfer efficiency of energy piles have reached a bottleneck, and a new approach for the continued enhancement of this technology must be investigated. In this study, powdered graphite with high heat transfer characteristics was included in a concrete mix to create graphite concrete piles with enhanced heat transfer characteristics. The results from theoretical analysis, laboratory testing, and numerical simulation indicate that using graphite to improve the heat transfer efficiency of a concrete material is an effective method for enhancing the thermal efficiency of an energy pile system. The research results also show that the heat transfer coefficient of the concrete exhibits greater improvement when the graphite content is greater than 15% under the same environmental temperature. After studying the performance of the proposed graphite concrete energy pile under different environmental temperatures (10°C, 20°C, 30°C, and 40°C), the results indicate that the working efficiency of the energy pile is better in the summer than in the winter. Finally, parameters such as the cast-in pipe configuration and pile spacing are optimized.


2015 ◽  
Vol 23 (02) ◽  
pp. 1550014 ◽  
Author(s):  
Daisuke Jige ◽  
Tomonobu Matsuno ◽  
Norihiro Inoue

The present study experimentally investigated the condensation heat transfer characteristics and condensate flow mode of R245fa on horizontal low-finned and microscopic-grooved tubes. Five low-finned tubes and a microscopic-grooved tube with tube diameters at the fin tip of approximately 19 mm were used. Experiments were conducted at a saturation temperature of 40°C. The fundamental heat transfer characteristics of the low-finned and microscopic-grooved tubes were experimentally investigated to clarify the flow modes of the condensate and the efficacy of the enhanced heat transfer.


2011 ◽  
Vol 281 (2) ◽  
pp. 254-262 ◽  
Author(s):  
Min Sheng ◽  
Hongyun Yang ◽  
Donald R. Cahela ◽  
Bruce J. Tatarchuk

PAMM ◽  
2014 ◽  
Vol 14 (1) ◽  
pp. 757-758
Author(s):  
Long Zhou ◽  
Rao Masood ◽  
Vojislav Jovicic ◽  
Ana Zbogar-Rasic ◽  
Victor Kempe ◽  
...  

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