TY - JOUR
T1 - Dual performance of novel steel pipe heat exchangers equipped in cast-in-place energy pile
AU - Lee, Seokjae
AU - Park, Sangwoo
AU - Kim, Dongkwan
AU - Ahn, Dongwook
AU - Choi, Hangseok
N1 - Funding Information:
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2019R1A2C2086647) and by POSCO Research Grant.
Funding Information:
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2019R1A2C2086647 ) and by POSCO Research Grant.
Publisher Copyright:
© 2021 Elsevier B.V.
PY - 2021/3/1
Y1 - 2021/3/1
N2 - Pile foundations support superstructures by transferring structural loads into the ground, where rocks or hard ground formations exist. Energy piles additionally utilize geothermal energy for heating and cooling buildings via embedded heat exchange pipes. However, when constructing energy piles, additional budgets are required for materials and labor to install conventional high-density polyethylene (HDPE) heat exchange pipes. The applicability of cast-in-place energy piles equipped with novel steel pipe heat exchangers (SPHXs) is investigated herein as substitutes for deformed rebars to reinforce concrete. Energy piles encasing SPHXs are expected to fulfill multiple functions of supporting structural loads and operating as heat exchangers without requiring additional heat exchange pipes. Two cast-in-place energy piles encasing SPHXs of different diameters were constructed in a test bed. Then, pile load tests (i.e., dynamic load test and lateral load test) were conducted to estimate the bearing capacities of these energy piles. Consequently, both energy piles secured safety factors greater than 2.0, and the allowable lateral loads were sufficient, indicating acceptable structural capacities as pile foundations. In addition, a thermal performance test (TPT) was performed on the selected energy pile, and the result was compared with that of a conventional cast-in-place energy pile to assess the heat exchange capacity of the energy pile with SPHXs. The thermal performance of the cast-in-place energy pile considered herein was 30% greater than that of the conventional energy pile of similar scale, which shows the applicability of the proposed energy piles.
AB - Pile foundations support superstructures by transferring structural loads into the ground, where rocks or hard ground formations exist. Energy piles additionally utilize geothermal energy for heating and cooling buildings via embedded heat exchange pipes. However, when constructing energy piles, additional budgets are required for materials and labor to install conventional high-density polyethylene (HDPE) heat exchange pipes. The applicability of cast-in-place energy piles equipped with novel steel pipe heat exchangers (SPHXs) is investigated herein as substitutes for deformed rebars to reinforce concrete. Energy piles encasing SPHXs are expected to fulfill multiple functions of supporting structural loads and operating as heat exchangers without requiring additional heat exchange pipes. Two cast-in-place energy piles encasing SPHXs of different diameters were constructed in a test bed. Then, pile load tests (i.e., dynamic load test and lateral load test) were conducted to estimate the bearing capacities of these energy piles. Consequently, both energy piles secured safety factors greater than 2.0, and the allowable lateral loads were sufficient, indicating acceptable structural capacities as pile foundations. In addition, a thermal performance test (TPT) was performed on the selected energy pile, and the result was compared with that of a conventional cast-in-place energy pile to assess the heat exchange capacity of the energy pile with SPHXs. The thermal performance of the cast-in-place energy pile considered herein was 30% greater than that of the conventional energy pile of similar scale, which shows the applicability of the proposed energy piles.
KW - Energy pile
KW - Ground Heat Exchanger (GHEX)
KW - Pile load test
KW - Steel pipe heat exchanger (SPHX)
KW - Thermal Performance Test (TPT)
UR - http://www.scopus.com/inward/record.url?scp=85100109573&partnerID=8YFLogxK
U2 - 10.1016/j.enbuild.2021.110725
DO - 10.1016/j.enbuild.2021.110725
M3 - Article
AN - SCOPUS:85100109573
SN - 0378-7788
VL - 234
JO - Energy and Buildings
JF - Energy and Buildings
M1 - 110725
ER -