TY - JOUR
T1 - Performance evaluation of coaxial-type GHEX in GSHP system installed in Korean residential building
AU - Lee, Seokjae
AU - Park, Sangwoo
AU - Kang, Minkyu
AU - Choi, Hangseok
N1 - Funding Information:
This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MOE) (2020R1A6A1A03045059).
Funding Information:
This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government ( MOE ) ( 2020R1A6A1A03045059 ).
Publisher Copyright:
© 2021 Elsevier B.V.
PY - 2021/3/15
Y1 - 2021/3/15
N2 - A coaxial-type ground heat exchanger (GHEX) is a closed-loop GHEX with heat exchange pipes in a borehole, arranged in a concentric tube-in-tube configuration. A coaxial-type GHEX enlarges the heat exchange area and induces turbulent flow more actively than conventional closed-loop GHEXs owing to the annular space formed by outer and inner pipes. Therefore, it improves the thermal performance of conventional GHEXs. Herein, the thermal performance of the coaxial-type GHEX was evaluated, and then compared with that of the closed-loop vertical GHEX. The Ground source heat pump (GSHP) system connected with the coaxial-type GHEXs was designed with the ground loop heat exchanger design program (i.e., GLHE-Pro). In accordance with the design, the GSHP system was constructed in a building basement, with four coaxial-type GHEXs and a closed-loop vertical GHEX for comparison purpose. Then, a series of field experiments (i.e., thermal response tests (TRTs), thermal performance tests (TPTs), short-term heating COP tests, and energy saving tests) were conducted to compare the thermal performance of the coaxial-type GHEXs and the closed-loop vertical GHEX with or without the GSHP system. As a result, the coaxial-type GHEX had 20% and 6.7% better thermal performance in TRT and TPT, respectively, than the closed-loop vertical GHEX. In addition, geothermal energy showed more stable performance with the coaxial-type GHEX in the GSHP system, than with the closed-loop vertical GHEX.
AB - A coaxial-type ground heat exchanger (GHEX) is a closed-loop GHEX with heat exchange pipes in a borehole, arranged in a concentric tube-in-tube configuration. A coaxial-type GHEX enlarges the heat exchange area and induces turbulent flow more actively than conventional closed-loop GHEXs owing to the annular space formed by outer and inner pipes. Therefore, it improves the thermal performance of conventional GHEXs. Herein, the thermal performance of the coaxial-type GHEX was evaluated, and then compared with that of the closed-loop vertical GHEX. The Ground source heat pump (GSHP) system connected with the coaxial-type GHEXs was designed with the ground loop heat exchanger design program (i.e., GLHE-Pro). In accordance with the design, the GSHP system was constructed in a building basement, with four coaxial-type GHEXs and a closed-loop vertical GHEX for comparison purpose. Then, a series of field experiments (i.e., thermal response tests (TRTs), thermal performance tests (TPTs), short-term heating COP tests, and energy saving tests) were conducted to compare the thermal performance of the coaxial-type GHEXs and the closed-loop vertical GHEX with or without the GSHP system. As a result, the coaxial-type GHEX had 20% and 6.7% better thermal performance in TRT and TPT, respectively, than the closed-loop vertical GHEX. In addition, geothermal energy showed more stable performance with the coaxial-type GHEX in the GSHP system, than with the closed-loop vertical GHEX.
KW - Coaxial-type GHEX
KW - Ground heat exchanger (GHEX)
KW - Ground source heat pump (GSHP)
KW - Thermal performance test (TPT)
KW - Thermal response test (TRT)
UR - http://www.scopus.com/inward/record.url?scp=85100082569&partnerID=8YFLogxK
U2 - 10.1016/j.enbuild.2021.110734
DO - 10.1016/j.enbuild.2021.110734
M3 - Article
AN - SCOPUS:85100082569
SN - 0378-7788
VL - 235
JO - Energy and Buildings
JF - Energy and Buildings
M1 - 110734
ER -