A New Environmentally Friendly Utilization of Energy Piles into Geotechnical Engineering in Northern China

Table 1

Research achievements on different types of heat exchangers cast-in-place energy piles.

Reference	U-shaped	Double U-shaped	Triple U-shaped	W-shaped	Double W-shaped	Spiral type
Park et al. [13]						★
Zarrella et al. [14]			▼			★
Go et al. [15]						★
Zhang et al. [16]						★
Xiang et al. [17]						★
Go et al. [18]						★
Lee et al. [19]						★
Yoon et al. [20]				◆		★
Wang et al. [21]						★
Wang et al. [22]						★
Park et al. [23]						★
Zhao et al. [24]	■			◆		★
Luo et al. [25]		▲	▼		●	★
Zarrella et al. [26]	■