๋ณธ ์ฐ๊ตฌ์์๋ ํ์ฅํ์ค ์๋์งํ์ผ์ ์ด๊ตํ ํ์ดํ ๋ฐฐ์น ํํ๋ณ ์ด๊ตํ์จ์ ์ ์ฐ์ ์ฒดํด์ ํ๋ก๊ทธ๋จ(FLUENT)์ ์ด์ฉํ์ฌ ํ๊ฐํ๊ณ , ์ด๋ฅผ ์ด์ฉํ์ฌ ์๋์งํ์ผ์ ์ค๊ณ๋ฒ์ ์ ์ํ์๋ค. ๋ฑ๊ฐ์ด๊ตํ์จ์ ์ฐ์ ํ๊ธฐ ์ํด ๋์ผํ ํ์ฅํ์ค๋ง๋ ์ ์์ ๋ํด ์ด๊ตํํ์ดํ ๋ฐฐ์น ํํ๋ฅผ W-ํ(์ง๋ ฌ), ๋ณตํฉ U-ํ(๋ณ๋ ฌ 4์), ๋์ ํ์ 3๊ฐ์ง๋ก ๊ณ ๋ คํ์๋ค. ๊ฑด๋ฌผ์ธก ๋ถํ์กฐ๊ฑด์ ์ฌ๋ฆ์ฒ ๋๋ฐฉ์ด์ฉ๋ฅผ ๋ชจ์ฌํ๊ธฐ ์ํด ์ํ์์ ์๋์งํ์ผ ์ ์
์จ๋, ์ฆ ํํธํํ ์ ์ถ์จ๋(Leaving water temperature, LWT)๋ฅผ <TEX>$35^{\circ}C$</TEX>๋ก ์ผ์ ํ๊ฒ ์ ์งํ์ฌ ์๋์งํ์ผ ์ ์ถ์จ๋, ์ฆ ํํธํํ ์ ์
์จ๋(Entering water temperature, EWT) ๋ณํ๋ฅผ ๊ด์ฐฐํ์๋ค. ์ง๋ฐ์ ์ต๋ ๊ฐ์๋ถํ๋ฅผ ์ ์ฉํ ๊ฒฝ์ฐ(100์๊ฐ ์ฐ์ ๋๋ฐฉ๋ถํ ์กฐ๊ฑด)์๋ 3๊ฐ์ง ์ด๊ตํ๊ธฐ ํํ๊ฐ ์ ์ฌํ ์ด๊ตํ์จ์ ๋ณด์ธ ๋ฐ๋ฉด, ์ค์ ํํธํํ ๊ฐ๋์ ์ํ ๊ฑด๋ฌผ ๋๋ฐฉ์ด์ฉ์ ๋ชจ์ฌํ๊ธฐ ์ํด ๊ฐํ์ ์ผ๋ก ์ผ์ผ 8์๊ฐ ์ด์ฉ-16์๊ฐ ์ ์ง๋ฅผ 7์ผ๊ฐ ๋ฐ๋ณต ํด์ํ ๊ฒฝ์ฐ์๋ W-ํ(์ง๋ ฌ์ฐ๊ฒฐ)๊ณผ ๋ณตํฉ U-ํ(๋ณ๋ ฌ 4์) ์ด๊ตํ๊ธฐ๋ ์ ์ฌํ ์ด๊ตํ์จ์ ๋ณด์ด๋, ๋์ ํ ์ด๊ตํ๊ธฐ๋ ํ์ดํ ๋ฃจํ ์ํธ ๊ฐ ์ด๊ฐ์ญ์ผ๋ก ์ธํด ๋ณตํฉ U-ํ ์ด๊ตํ๊ธฐ์ ๋นํด ์ฝ 86%์ ์ด๊ตํ์จ์ ๊ฐ๋ ๊ฒ์ผ๋ก ํ๊ฐ๋์๋ค. ์ ์ฐ์ ์ฒดํด์์ ์ํด ๊ณ์ฐ๋ ์ด๊ตํํ์ดํ ๋ฐฐ์น ํํ๋ณ ์๋์งํ์ผ์ ๋ฑ๊ฐ์ด๊ตํ์จ์ ์๋์งํ์ผ ์ค๊ณํ๋ก๊ทธ๋จ(PILESIM2)์ ์ ์ฉํ์ฌ ๋ค์ํ ํ์์ ํ์ฅํ์ค ์๋์งํ์ผ์ ๋ํ ์ค๊ณ๋ฒ๊ณผ ๋ํ์ ์ธ ์ค๊ณ๋ณ์์ ๋ํ ์ค๊ณ๋ํ๋ฅผ ์ ์ํ์๋ค. In this paper, a relative heat exchange rate is numerically compared for cast-in-place concrete energy piles with different heat exchange pipe configurations, and a new design method for energy piles is proposed. An equivalent heat exchange rate was estimated for the W-type (one series loop), multiple U-type (four parallel loops), and coil-type heat exchanger installed in the same large-diameter drilled shaft. In order to simulate a cooling operation in summer by a CFD analysis, the LWT (leaving water temperature) into a energy pile was fixed at <TEX>$35^{\circ}C$</TEX> and then the EWT (entering water temperature) into a heat pump was monitored. In case of continuously applying the artificial maximum cooling load for 100 hours, all of the three types of heat exchangers show the marginally similar heat exchange rate. However, in case of intermittently applying the cooling load with a cycle of 8 hours operation-16 hours off for 7 consecutive days, the coil type heat exchanger exhibits a heat exchange rate only 86 % of the multiple U-type due to measurable thermal interference between pipe loops in the energy pile. On the other hand, the W-type possesses the similar heat exchange rate to the multiple U-type. The equivalent heat exchange rates for each configuration of heat exchangers obtained from the CFD analysis were adopted for implementing the commercial design program (PILESIM2). Finally, a design method for cast-in-place concrete energy piles is proposed along with a design chart in consideration of typical design factors.