Mobile QR Code QR CODE : Journal of the Korean Society of Civil Engineers

  1. *KAIST ๊ฑด์„ค๋ฐํ™˜๊ฒฝ๊ณตํ•™๊ณผ ๋ฐ•์‚ฌ๊ณผ์ •, ๊ณตํ•™์„์‚ฌ ()
  2. **KAIST ๊ฑด์„ค๋ฐํ™˜๊ฒฝ๊ณตํ•™๊ณผ ์„๋ฐ•์‚ฌํ†ตํ•ฉ๊ณผ์ • ()
  3. ***KAIST ๊ฑด์„ค๋ฐํ™˜๊ฒฝ๊ณตํ•™๊ณผ ๊ต์ˆ˜, ๊ณตํ•™๋ฐ•์‚ฌ (***KAIST)
  4. ****์ธ์ฒœ๊ตญ์ œ๊ณตํ•ญ๊ณต์‚ฌ ์—ฐ๊ตฌ๊ฐœ๋ฐœ๋‹จ ์ „๋ฌธ์—ฐ๊ตฌ์›, ๊ณตํ•™๋ฐ•์‚ฌ ()


์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ, ์—ด์„ฑ๋Šฅ ์‹คํ—˜, ์—ด์‘๋‹ต ์‹คํ—˜, ์—ด๊ตํ™˜์œจ
Ground heat exchanger, Thermal performance test, Thermal response test, Heat exchange rate

  • 1. ์„œ ๋ก 

  • 2. ํ˜„์žฅ ์—ด์„ฑ๋Šฅ ์‹คํ—˜

  •   2.1 ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ ์„ค์น˜ ์กฐ๊ฑด

  •   2.2 ์—ด์„ฑ๋Šฅ ์‹คํ—˜ ์›๋ฆฌ

  • 3. ํ˜„์žฅ ์—ด์‘๋‹ต ์‹คํ—˜ ๊ฒฐ๊ณผ

  • 4. ํ˜„์žฅ ์—ด์„ฑ๋Šฅ ์‹คํ—˜ ๊ฒฐ๊ณผ

  •   4.1 100์‹œ๊ฐ„ ๋ƒ‰๋ฐฉ ๊ฐ€๋™ ์—ฐ์† ์šด์ „ ์‹คํ—˜ ๊ฒฐ๊ณผ

  •   4.2 ๋ƒ‰๋ฐฉ ๊ฐ€๋™ ๋ถ€๋ถ„ ์šด์ „ ์‹คํ—˜ ๊ฒฐ๊ณผ

  •   4.3 ๋ƒ‰๋ฐฉ ๊ฐ€๋™ 6๊ฐœ์›” ์žฅ๊ธฐ์„ฑ๋Šฅ ์˜ˆ์ธก ๊ฒฐ๊ณผ

  • 5. ๊ฒฐ ๋ก 

1. ์„œ ๋ก 

์ตœ๊ทผ ๋“ค์–ด ์ง€๊ตฌ ์˜จ๋‚œํ™”, ํ™”์„ ์—๋„ˆ์ง€ ๊ณ ๊ฐˆ๋กœ ์ธํ•˜์—ฌ ์‹ ์žฌ์ƒ์—๋„ˆ์ง€ ์ด์šฉ์— ๋Œ€ํ•œ ๊ด€์‹ฌ๊ณผ ์ˆ˜์š”๊ฐ€ ๋Š˜์–ด๋‚˜๋ฉด์„œ ์ง€์—ด์› ์—ดํŽŒํ”„ ์‹œ์Šคํ…œ(ground source heat pump systems)์˜ ํ•„์š”์„ฑ์ด ๋‚˜๋‚ ์ด ์ฆ๋Œ€๋˜๊ณ  ์žˆ๋‹ค. ์ง€์—ด์› ์—ดํŽŒํ”„ ์‹œ์Šคํ…œ์€ ์—ฐ์ค‘ ์ผ์ •ํ•œ ์ง€์ค‘์—ด์„ ์—ดํŽŒํ”„์˜ ์—ด์›(heat source)๊ณผ ํžˆํŠธ ์‹ฑํฌ(heat sink)๋กœ ํ™œ์šฉํ•˜์—ฌ ๊ฑด๋ฌผ์˜ ๋ƒ‰๋‚œ๋ฐฉ๊ณผ ๊ธ‰ํƒ•์„ ๋™์‹œ์— ๊ตฌํ˜„ํ•˜๊ธฐ ๋•Œ๋ฌธ์— ์•ˆ์ „ํ•˜๊ณ  ํšจ์œจ์ ์ธ ์ฒญ์ • ์‹ ์žฌ์ƒ์—๋„ˆ์ง€์ด๋‹ค.

๋˜ํ•œ ์ง€์—ด์› ์—ดํŽŒํ”„ ์‹œ์Šคํ…œ์€ ์—๋„ˆ์ง€ ์ ˆ์•ฝํ˜• ๊ธฐ์ˆ ๋กœ์จ ๊ตญ๋‚ด ์–ด๋””์„œ๋‚˜ ์ด์šฉํ•  ์ˆ˜ ์žˆ๋Š” ์œ ๋น„์ฟผํ„ฐ์Šค ์—๋„ˆ์ง€๋กœ ์—ฌ๊ฒจ์ง„๋‹ค(Geothermal Energy Education Center, 2011). ์ด ์‹œ์Šคํ…œ์˜ ๊ตฌ์„ฑ ์š”์†Œ ์ค‘ ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ(ground heat exchanger)๋Š” ์ „์ฒด ์‹œ์Šคํ…œ์˜ ์„ฑ๋Šฅ๊ณผ ์ดˆ๊ธฐ ์„ค์น˜๋น„๋ฅผ ๊ฒฐ์ •ํ•˜๋Š” ์ค‘์š”ํ•œ ์š”์†Œ์ด๋ฉฐ ์ผ๋ฐ˜์ ์œผ๋กœ ๊นŠ์ด 150โˆผ200m์˜ ์ˆ˜์ง๋ฐ€ํํ˜• ํƒ€์ž…์ด ๊ฐ€์žฅ ๋งŽ์ด ์‚ฌ์šฉ๋˜๊ณ  ์žˆ๋‹ค. ์ˆ˜์ง๋ฐ€ํํ˜• ์—ด๊ตํ™˜๊ธฐ๋Š” ์ˆ˜์ง์œผ๋กœ ์ฒœ๊ณต๋œ ๋ณด์–ดํ™€๊ณผ ์ง€์ค‘๊ณผ์˜ ์—ด๊ตํ™˜ ํŒŒ์ดํ”„, ๊ทธ๋ฆฌ๊ณ  ๋ณด์–ดํ™€๊ณผ ํŒŒ์ดํ”„ ์‚ฌ์ด์˜ ๋นˆ ๊ณต๊ฐ„์„ ์ฑ„์šฐ๋Š” ๊ทธ๋ผ์šฐํŠธ๋กœ ๊ตฌ์„ฑ๋œ๋‹ค.

์ˆ˜์ง๋ฐ€ํํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ๋Š” ์ดˆ๊ธฐ ๋†’์€ ์‹œ๊ณต๋น„๋กœ ์ธํ•˜์—ฌ ๋ณด๋‹ค ๋†’์€ ์—ดํšจ์œจ์„ ์–ป๊ธฐ ์œ„ํ•œ ์—ฐ๊ตฌ๋“ค์ด ๋งŽ์ด ์ง„ํ–‰๋˜๊ณ  ์žˆ๋‹ค. ์—ด๊ตํ™˜๊ธฐ๋ฅผ ํ†ตํ•ด์„œ ์ฃผ๋ณ€ ์ง€๋ฐ˜๊ณผ ์—ด์„ ๊ตํ™˜ํ•˜๋Š” ์—ด์ „๋‹ฌ์€ ๋ณด์–ดํ™€ ๋‚ด์˜ ๊ทธ๋ผ์šฐํŠธ์˜ ์—ด๋ฌผ์„ฑ, ์—ด๊ตํ™˜๊ธฐ ํƒ€์ž… ๋ฐ ๊ฐ„๊ฒฉ ๊ทธ๋ฆฌ๊ณ  ์—ด๊ตํ™˜๊ธฐ ๋ฐฐ์—ด ๋ฐ ์ˆœํ™˜์ˆ˜ ํŠน์„ฑ ๋“ฑ ๋‹ค์–‘ํ•œ ์ธ์ž์— ์˜ํ•ด ์˜ํ–ฅ์„ ๋ฐ›์œผ๋ฉฐ ์ด์— ๋Œ€ํ•œ ๋งŽ์€ ์—ฐ๊ตฌ๊ฐ€ ์ˆ˜ํ–‰๋˜๊ณ  ์žˆ๋‹ค(Park et al., 2013; Park et al., 2012; Lim et al., 2011; Min and Choi, 2011; Lee et al., 2010; Sohn et al., 2005). ์ผ๋ฐ˜์ ์œผ๋กœ ์ˆ˜์ง๋ฐ€ํํ˜•์—์„œ ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ ํƒ€์ž…์€ ์‹œ๊ณต์˜ ํŽธ๋ฆฌ์„ฑ ๋“ฑ์œผ๋กœ ์ธํ•ด U์žํ˜•์ด ๊ฐ€์žฅ ๋งŽ์ด ์ ์šฉ๋˜๊ณ  ์žˆ์œผ๋‚˜ U์žํ˜• ์™ธ์˜ ๋‹ค์–‘ํ•œ ์—ด๊ตํ™˜๊ธฐ ํƒ€์ž…์— ๋”ฐ๋ฅธ ์—ด์ „๋‹ฌ ๊ฑฐ๋™์— ๋Œ€ํ•œ ์—ฐ๊ตฌ๋Š” ๋ถ€์กฑํ•œ ์‹ค์ •์ด๋‹ค.

๋”ฐ๋ผ์„œ ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” U์žํ˜•๋ณด๋‹ค ๋„“์€ ์—ด๊ตํ™˜ ์ ‘์ด‰๋ฉด์ ์„ ๊ฐ€์ง€๋Š” W์žํ˜•๊ณผ 2U์žํ˜• ๊ทธ๋ฆฌ๊ณ  ์—๋„ˆ์ง€ ํŒŒ์ผ์— ๋„๋ฆฌ ์ ์šฉ๋˜๊ณ  ์žˆ๋Š” ์ฝ”์ผํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ์— ๋Œ€ํ•œ ์—ดํšจ์œจ์„ ๋น„๊ตํ•˜๊ณ ์ž ํ•˜์˜€์œผ๋ฉฐ ์ด๋ฅผ ์œ„ํ•ด ์ธ์ฒœ๊ตญ์ œ๊ณตํ•ญ ์ œ 2์—ฌ๊ฐํ„ฐ๋ฏธ๋„์ด ๊ฑด์„ค๋  ๋ถ€์ง€์— ์ˆ˜์ง ๋ฐ€ํํ˜• ํƒ€์ž…์˜ U์žํ˜•, W์žํ˜•, 2U์žํ˜• ๊ทธ๋ฆฌ๊ณ  ์ฝ”์ผํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ๋ฅผ ์„ค์น˜ํ•˜์˜€๋‹ค. ์šฐ์„  ํ˜„์žฅ ์ง€๋ฐ˜์˜ ์—ด์ „๋„๋„๋ฅผ ๋„์ถœํ•˜๊ธฐ ์œ„ํ•˜์—ฌ U์žํ˜•, W์žํ˜• ๊ทธ๋ฆฌ๊ณ  2U์žํ˜• ์—ด๊ตํ™˜๊ธฐ๋ฅผ ์ด์šฉํ•˜์—ฌ ํ˜„์žฅ ์—ด์‘๋‹ต ์‹œํ—˜์„ ์‹ค์‹œํ•˜์˜€๋‹ค. ๊ทธ ํ›„ ์—ด๊ตํ™˜๊ธฐ ํ˜•ํƒœ๋ณ„ ์—ด๊ตํ™˜์œจ์„ ์ธก์ •ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ํ˜„์žฅ ์—ด์„ฑ๋Šฅ ์‹คํ—˜์„ ์ˆ˜ํ–‰ํ•˜์˜€๋‹ค. ํ˜„์žฅ ์—ด์„ฑ๋Šฅ ์‹คํ—˜์€ ์šด์ „ ์กฐ๊ฑด๋ณ„ ์—ด๊ตํ™˜์œจ์˜ ์ฐจ์ด๋ฅผ ๋ถ„์„ํ•˜๊ณ ์ž 100์‹œ๊ฐ„ ์—ฐ์† ์šด์˜ ์กฐ๊ฑด๊ณผ ๋ถ€๋ถ„์šด์˜์กฐ๊ฑด(8์‹œ๊ฐ„ ์šด์šฉ, 16์‹œ๊ฐ„ ๋Œ€๊ธฐ)์œผ๋กœ 5์ผ๊ฐ„ ์ง„ํ–‰ํ•˜์˜€๋‹ค. ๋˜ํ•œ ๊ณ„์ธก๋œ ๊ฐ’์„ ๊ทผ๊ฑฐ๋กœ ์ถ”์„ธ์„  ๋ถ„์„(regression analysis)์„ ํ†ตํ•˜์—ฌ 6๊ฐœ์›” ๋™์•ˆ์˜ ์—ด์„ฑ๋Šฅ ๊ฐ’์„ ์˜ˆ์ธกํ•˜์˜€๋‹ค. ํ˜„์žฅ ์—ด์„ฑ๋Šฅ ์‹คํ—˜์„ ํ†ตํ•ด ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ ํ˜•ํƒœ๋ณ„ ์—ดํšจ์œจ์„ ๋ถ„์„ํ•˜์—ฌ ์ด์˜ ์ ์šฉ์„ฑ์— ๋Œ€ํ•ด ๋…ผ์˜ํ•ด ๋ณด์•˜๋‹ค.

2. ํ˜„์žฅ ์—ด์„ฑ๋Šฅ ์‹คํ—˜

2.1 ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ ์„ค์น˜ ์กฐ๊ฑด

๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ์ธ์ฒœ๊ตญ์ œ๊ณตํ•ญ ์ œ 2์—ฌ๊ฐํ„ฐ๋ฏธ๋„ ๊ฑด์„ค ๋ถ€์ง€์— U์žํ˜•๊ณผ W์žํ˜• ๋ฐ 2U์žํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ๋ฅผ 15cm ๋ณด์–ดํ™€ ์ง๊ฒฝ ๋‚ด์— ์ˆ˜์ง ๊นŠ์ด 50m ๋กœ ์„ค์น˜ํ•˜์˜€๋‹ค. ์ผ๋ฐ˜์ ์œผ๋กœ U์žํ˜• ๋ฐ W์žํ˜•๊ณผ ๊ฐ™์€ ๋ผ์ธํ˜• ์—ด๊ตํ™˜๊ธฐ์˜ ์ง๊ฒฝ์€ 20โˆผ40mm ์ •๋„๋กœ 15cm์˜ ๋ณด์–ดํ™€ ์ง๊ฒฝ์— ์„ค์น˜๋˜๊ธฐ์— ๋ณธ ์—ฐ๊ตฌ์—์„œ๋„ 15cm์˜ ๋ณด์–ดํ™€์„ ์ฒœ๊ณตํ•˜์˜€๋‹ค. ํ•˜์ง€๋งŒ ์ฝ”์ผํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ์˜ ๊ฒฝ์šฐ ์ฝ”์ผ์˜ ์™ธ๊ฒฝ์ด 28cm ์ด๊ธฐ์— ๋ณด์–ดํ™€ ์ง๊ฒฝ์€ 30cm ์˜€์œผ๋ฉฐ ์ฝ”์ผ ํ”ผ์น˜ ๊ฐ„๊ฒฉ 5cm์— ์ˆ˜์ง ๊นŠ์ด 30m๋กœ ์„ค์น˜๋˜์—ˆ๋‹ค. ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ๋Š” PB(polybutylene) ์†Œ์žฌ์˜ ํŒŒ์ดํ”„(์™ธ๊ฒฝ/๋‚ด๊ฒฝ: 20mm/16mm)๊ฐ€ ์‚ฌ์šฉ๋˜์—ˆ๊ณ  ๋ณด์–ดํ™€ ๋‚ด๋ถ€๋Š” ๋ฒคํ† ๋‚˜์ดํŠธ ๊ทธ๋ผ์šฐํŠธ๋ฅผ ์ฑ„์šด ํ˜•ํƒœ๋กœ ๊ตฌ์„ฑ๋˜์–ด ์žˆ์œผ๋ฉฐ ์—ด๊ตํ™˜๊ธฐ ๋ฐฐ์น˜ ์ƒํƒœ๋Š” Fig. 1๊ณผ ๊ฐ™๋‹ค. ๋ณด์–ดํ™€ ๊ฐ„ ๊ฐ„๊ฒฉ์€ 6m ์ด๋ฉฐ ์‹คํ—˜์ง€์—ญ์— ๋Œ€ํ•ด ์ง€๋ฐ˜์กฐ์‚ฌ๋ฅผ ์ˆ˜ํ–‰ํ•œ ๊ฒฐ๊ณผ ์‹คํŠธ ๋ฐ ๋ชจ๋ž˜์งˆ ํ‡ด์ ์ธต๊ณผ ํ’ํ™”์•”, ์—ฐ์•” ๋“ฑ์œผ๋กœ ๊ตฌ์„ฑ๋˜์–ด ์žˆ๋‹ค(Fig. 2). ๋งค๋ฆฝ์ธต์˜ N์น˜๋Š” 2/30โˆผ38/30์ •๋„๋กœ ๋งค์šฐ ๋А์Šจ(very loose) ๋‚ด์ง€ ์กฐ๋ฐ€(dense)ํ•œ ์ƒํƒœ๋ฅผ ๋‚˜ํƒ€๋‚ด๊ณ  ์žˆ๋‹ค. ๋˜ํ•œ ํ‡ด์ ์ธต์€ ๊ตณ์€์ ํ† , ์‹คํŠธ ๋ฐ ๋ชจ๋ž˜์„ž์ธ ์‹คํŠธ์ธต์œผ๋กœ ๊ตฌ์„ฑ๋˜์–ด ์žˆ์œผ๋ฉฐ 9/30โˆผ33/30์˜ N ๊ฐ’์„ ๋‚˜ํƒ€๋ƒˆ๋‹ค. ์ง€ํ•˜์ˆ˜์œ„๋Š” ์ง€ํ‘œ๋ฉด์—์„œ GL(-)3.5m ์‹ฌ๋„์— ์œ„์น˜ํ•ด ์žˆ์—ˆ์œผ๋ฉฐ GL(-)30m ์ง€์ ๋ถ€ํ„ฐ ํ’ํ™”์•” ๋ฐ ์—ฐ์•”์ด ์ถœ์—ฐํ•˜๋Š” ๊ฒƒ์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ํ’ํ™”์•”์€ ๋ชจ์•”์ธ ํ™”๊ฐ•์•”์ด ๋งค์šฐ ์‹ฌํ•˜๊ฒŒ ํ’ํ™”๋œ ์ƒํƒœ๋กœ ๋ชจ์•”์˜ ์กฐ์ง๊ณผ ํ˜•ํƒœ๋Š” ๊ทธ๋Œ€๋กœ ์ž”์กดํ•˜๊ณ  ์žˆ์—ˆ์œผ๋ฉฐ ํ™ฉ๊ฐˆ์ƒ‰ ๋‚ด์ง€ ๋‹ด๊ฐˆ์ƒ‰์„ ๋‚˜ํƒ€๋ƒˆ์œผ๋ฉฐ 50/13โˆผ50/2 ์ •๋„์˜ N ๊ฐ’์„ ๋ณด์˜€๋‹ค. Fig. 3์˜ (a)โˆผ(e)๋Š” ์‹คํ—˜ ์ „ ์ฃผ์š” ์‹œ๊ณต๊ณผ์ •์„ ๋ณด์—ฌ์ฃผ๊ณ  ์žˆ๋‹ค.

PIC2221.jpg

Fig. 1. Diagram of GHE

PIC230C.gif

Fig. 2. Drill Log of the Test Site

2.2 ์—ด์„ฑ๋Šฅ ์‹คํ—˜ ์›๋ฆฌ

์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ์˜ ์—ด์ „๋‹ฌ ๋ฉ”์ปค๋‹ˆ์ฆ˜์€ ์—ด์ „๋‹ฌ ์œ ์ฒด๊ฐ€ ๋ณด์–ดํ™€ ๋‚ด์˜ ํŒŒ์ดํ”„ ๋‚ด๋ฅผ ์ด๋™ํ•˜๋ฉด์„œ ๊ทธ๋ผ์šฐํŠธ ์žฌ๋ฃŒ์™€ ์ฃผ๋ณ€์˜ ์ง€๋ฐ˜์œผ๋กœ ์—ด์„ ํก์ˆ˜ ๋˜๋Š” ๋ฐฉ์ถœํ•˜๋Š” ๊ณผ์ •์ด๋‹ค. ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ์™€ ์ฃผ๋ณ€ ์ง€๋ฐ˜์œผ๋กœ์˜ ์—ด์ „๋‹ฌ ๊ฑฐ๋™์€ ๋ณต์žกํ•˜๊ณ  ๋ณตํ•ฉ์ ์ธ ๋ฉ”์ปค๋‹ˆ์ฆ˜์ด ํ•„์š”ํ•˜์ง€๋งŒ ์ผ๋ฐ˜์ ์œผ๋กœ ์ง€๋ฐ˜์œผ๋กœ์˜ ์—ด์ „๋‹ฌ์€ ์ „๋„์— ์˜ํ•ด ์ด๋ฃจ์–ด์ง„๋‹ค(Brandl, 2006). ์—ด์ „๋‹ฌ ๋ฐฉ์ •์‹์˜ ํ•ด๋ฅผ ๊ตฌํ•˜๋Š” ๋ฐฉ๋ฒ•์€ ์„ ํ˜• ์—ด์›๋ชจ๋ธ(line source model), ์›ํ†ตํ˜• ์—ด์›๋ชจ๋ธ(cylindrical source model) ๊ทธ๋ฆฌ๊ณ  ์ˆ˜์น˜ํ•ด์„ ๋ชจ๋ธ ๋“ฑ์ด ์žˆ์œผ๋ฉฐ ์ด ์ค‘ ๋ฌดํ•œ ์„ ํ˜• ์—ด์› ๋ชจ๋ธ(infinite line source model)์€ ํ•ด์„์˜ ๊ฐ„ํŽธ์„ฑ๊ณผ ํŽธ๋ฆฌ์„ฑ์œผ๋กœ ์ธํ•ด ๊ฐ€์žฅ ๋งŽ์ด ์‚ฌ์šฉ๋˜๊ณ  ์žˆ๋‹ค. ๋ฌดํ•œ ์„ ํ˜• ์—ด์› ๋ชจ๋ธ์„ ์ด์šฉํ•œ ์œ ํšจ ์—ด์ „๋„๋„ ๋„์ถœ ๊ณผ์ •์€ ์—ฌ๋Ÿฌ ๋ฌธํ—Œ์—์„œ ์ œ์‹œ๋˜๊ณ  ์žˆ๋‹ค(Pahud and Matthey, 2001; Lee et al., 2010). ๋ฌดํ•œ ์„ ํ˜• ๋ชจ๋ธ์„ ํ†ตํ•œ ์ง€์ค‘ ์—ด์ „๋„๋„(PIC2489.gif)๋Š” Eq. (1)๊ณผ ๊ฐ™์€ ๊ฐ„ํŽธ์‹์„ ์‚ฌ์šฉํ•˜์—ฌ ์—ด์‘๋‹ต ์‹œํ—˜์„ ํ†ตํ•ด ์‹œ๊ฐ„์— ๋”ฐ๋ฅธ ์œ ์ฒด์˜จ๋„๋ฅผ ์ธก์ •ํ•˜๊ณ  ๊ทธ ๊ฒฐ๊ณผ๋ฅผ PIC249A.gif์˜ ๋ฐ˜๋Œ€์ˆ˜ ๊ด€๊ณ„๋กœ ๋„์‹œํ•œ ๊ทธ๋ž˜ํ”„์˜ ๊ธฐ์šธ๊ธฐ(PIC249B.gif)๋ฅผ ํ†ตํ•ด ์‚ฐ์ถœํ•  ์ˆ˜ ์žˆ๋‹ค.

PIC233C.jpg

PIC235C.jpg

PIC23DA.jpg

(a) Drilling of GHE

(b) Installation of GHE

(C) Bentonite Grouting

PIC240A.gif

PIC2469.gif

(d) Curing of Grout

(e) Connection to TPT Equipment

Fig. 3. Construction Process of GHE

Table 1. TPT (Thermal Performance Test) Equipment

Item

Specification

Heater

Capacity 5kW

PIC685B.gif

Water Tank

20L (SUS 304)

Flow meter

2โˆผ20 lpm

Pump

40m head,

 100 lpm

Sensor

RTD 

PIC687C.gif       (1)

์—ฌ๊ธฐ์„œ Q๋Š” ๋‹จ์œ„ ์‹œ๊ฐ„๋‹น ์ฃผ์ž…๋œ ์—ด๋Ÿ‰, L์€ ๋ณด์–ดํ™€์˜ ๊ธธ์ด, PIC688C.gif๋Š” ์œ ์ฒด์˜ ํ‰๊ท  ์˜จ๋„, t๋Š” ์‹œ๊ฐ„์„ ๋œปํ•œ๋‹ค.

๋˜ํ•œ ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ์˜ ์—ด๊ตํ™˜์œจ์„ ์‚ฐ์ •ํ•˜๊ธฐ ์œ„ํ•ด์„œ๋Š” ์—ด์ „๋‹ฌ ๋งค๊ฐœ์ฒด์˜ ์—ด ์ €ํ•ญ์„ ์‚ฐ์ถœํ•˜์—ฌ ์—ด๊ตํ™˜์œจ์„ ์‚ฐ์ •ํ•˜์—ฌ์•ผ ํ•œ๋‹ค. ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ์‹คํ—˜์„ ํ†ตํ•˜์—ฌ ์—ด๊ตํ™˜๊ธฐ๋กœ ์œ ์ž…๋˜๋Š” ์˜จ๋„๋ฅผ ์ผ์ •ํ•˜๊ฒŒ ์ œ์–ดํ•˜๋ฉด์„œ ์œ ์ถœ์ˆ˜ ์˜จ๋„๋ฅผ ์ธก์ •ํ•œ ํ›„ Eq. (2)๋ฅผ ์ด์šฉํ•˜์—ฌ ์—ด ๊ตํ™˜์œจ์„ ์‚ฐ์ •ํ•˜์˜€๋‹ค.

PIC68CC.gif      (2)

์—ฌ๊ธฐ์„œ, PIC68FC.gif์€ ์ˆœํ™˜์ˆ˜์˜ ์งˆ๋Ÿ‰ ํ๋ฆ„ ์†๋„(mass flow rate, PIC690C.gif)์ด๊ณ  c๋Š” ์ˆœํ™˜์ˆ˜์˜ ๋น„์—ด ๊ทธ๋ฆฌ๊ณ  L์€ ๋ณด์–ดํ™€์˜ ๊นŠ์ด์ด๋‹ค. ๋ณธ ์—ฐ๊ตฌ์—์„œ ์ œ์ž‘๋œ ์—ด์„ฑ๋Šฅ ์‹คํ—˜๊ธฐ๋Š” ์ง€์ค‘์˜ ๋ณด์–ดํ™€์— ๋งค์„ค๋œ ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ ๋‚ด๋ถ€๋ฅผ ์ˆœํ™˜์ˆ˜๋กœ ๊ณต๊ธ‰ํ•˜๊ณ  ์œ ์ฒด์˜ ์˜จ๋„๋ณ€ํ™”๋ฅผ ๊ฐ์ง€ํ•˜๋Š” ์‹œ์Šคํ…œ์œผ๋กœ ๊ตฌ์„ฑ๋˜์–ด์ ธ ์žˆ๋‹ค. ์ง€๋ฐ˜์˜ ์œ ํšจ ์—ด์ „๋„๋„๋ฅผ ์ธก์ •ํ•  ์ˆ˜ ์žˆ๋Š” ์—ด์‘๋‹ต ์‹คํ—˜ ์žฅ์น˜์™€ ๊ฐ™์ด ์ˆœํ™˜์ˆ˜๋ฅผ ๊ณต๊ธ‰ํ•˜๋Š” ์ˆ˜์กฐ ๋‚ด์— ํžˆํ„ฐ๋ฅผ ํ†ตํ•˜์—ฌ ์ผ์ •ํ•œ ์ „๋ ฅ์„ ๊ณต๊ธ‰ํ•  ์ˆ˜ ์žˆ๋‹ค. ๋˜ํ•œ ํžˆํ„ฐ๋‚ด์˜ ์˜จ๋„๋ฅผ ์ผ์ •ํ•˜๊ฒŒ ์ œ์–ดํ•  ์ˆ˜ ์žˆ๋Š” ์˜จ๋„ ์ œ์–ด๊ธฐ๊ฐ€ ์„ค์น˜๋˜์–ด ์žˆ๊ธฐ์— ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ๋กœ ํ˜๋Ÿฌ๊ฐ€๋Š” ์œ ์ž…์ˆ˜ ์˜จ๋„๋ฅผ ์ผ์ •ํ•˜๊ฒŒ ์œ ์ง€ํ•˜๊ณ  ์œ ์ถœ์ˆ˜ ์˜จ๋„๋ฅผ ๊ณ„์ธกํ•˜๋ฉด ์ง€๋ฐ˜๊ณผ์˜ ์—ด๊ตํ™˜์œจ์„ ์ธก์ •ํ•  ์ˆ˜ ์žˆ๋Š” ๊ธฐ๋Šฅ๋„ ํƒ‘์žฌ๋˜์–ด ์žˆ๋‹ค. ์ฆ‰ ๋ณธ ์žฅ๋น„๋ฅผ ์ด์šฉํ•˜๋ฉด ์ง€๋ฐ˜์˜ ์—ด์ „๋„๋„๋ฅผ ์ธก์ •ํ•  ์ˆ˜ ์žˆ๋Š” ์—ด์‘๋‹ต ์‹คํ—˜๋ฟ๋งŒ ์•„๋‹ˆ๋ผ ์—ด๊ตํ™˜์œจ์„ ์ธก์ •ํ•  ์ˆ˜ ์žˆ๋Š” ์—ด์„ฑ๋Šฅ ์‹คํ—˜๋„ ๊ฐ€๋Šฅํ•˜๋‹ค๊ณ  ํ•  ์ˆ˜ ์žˆ๋‹ค. Table 1์€ ์—ด์„ฑ๋Šฅ ์‹คํ—˜๊ธฐ์˜ ์ œ์›์„ ๋‚˜ํƒ€๋‚ธ๋‹ค.

3. ํ˜„์žฅ ์—ด์‘๋‹ต ์‹คํ—˜ ๊ฒฐ๊ณผ

Fig. 3๊ณผ ๊ฐ™์ด ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ ์„ค์น˜ ํ›„ ์ง€๋ฐ˜์˜ ์—ด์ „๋„๋„๋ฅผ ์‚ฐ์ •ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ U, W ๊ทธ๋ฆฌ๊ณ  2U์žํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ์— ๋Œ€ํ•ด ํ˜„์žฅ ์—ด์‘๋‹ต ์‹คํ—˜์„ ์‹ค์‹œํ•˜์˜€๋‹ค. ์ฝ”์ผํ˜• ๊ตํ™˜๊ธฐ์˜ ๊ฒฝ์šฐ ๋ผ์ธ ํ˜•ํƒœ๊ฐ€ ์•„๋‹ˆ๊ธฐ์— Eq. (1)์˜ ๋ฌดํ•œ ์„ ํ˜• ์—ด์› ๋ชจ๋ธ์„ ์ ์šฉํ•˜๊ธฐ๋Š” ์–ด๋ ค์šด ๊ฒƒ์œผ๋กœ ์•Œ๋ ค์ ธ ์žˆ๋‹ค(Yoon et al., 2012). ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ๊ฐ€ ์„ค์น˜๋œ ๋ณด์–ดํ™€์— ์žฅ๋น„๋ฅผ ์—ฐ๊ฒฐํ•˜์—ฌ 48์‹œ๊ฐ„ ๋™์•ˆ ํ˜„์žฅ ์—ด์‘๋‹ต ์‹œํ—˜์„ ์ˆ˜ํ–‰ํ•˜์˜€๋‹ค. ํžˆํ„ฐ ํˆฌ์ž… ์ „ 30๋ถ„๊ฐ„ ๋ฌด๋ถ€ํ•˜ ์šด์ „์„ ํ†ตํ•ด ๋„์ถœ๋œ ์ง€๋ฐ˜์˜ ์ดˆ๊ธฐ ์˜จ๋„๋Š” 15.8โˆผ16.5ยฐC ์˜€์œผ๋ฉฐ ์‹คํ—˜์‹œ ์œ ๋Ÿ‰์€ ๋‚œ๋ฅ˜ ์กฐ๊ฑด ํ˜•์„ฑ์„ ์œ„ํ•˜์—ฌ 6โˆผ8 lpm ๊ฐ’์œผ๋กœ ์ œ์–ดํ•˜์˜€๊ณ  ์ˆœํ™˜์ˆ˜ ์˜จ๋„๋ฟ๋งŒ ์•„๋‹ˆ๋ผ ์œ ๋Ÿ‰๊ฐ’๋„ 10๋ถ„ ๊ฐ„๊ฒฉ์œผ๋กœ ์‹ค์‹œ๊ฐ„์œผ๋กœ ๊ณ„์ธก ์ €์žฅํ•˜์˜€๋‹ค. U์žํ˜• ์—ด๊ตํ™˜๊ธฐ์— ํˆฌ์ž…๋˜๋Š” ์—ด๋Ÿ‰์€ 2000W ์˜€์œผ๋ฉฐ W์žํ˜•๊ณผ 2U์žํ˜• ์—ด๊ตํ™˜๊ธฐ์—๋Š” 3000W์˜ ์ „๋ ฅ์„ ํˆฌ์ž…ํ•˜์˜€๋‹ค. 48์‹œ๊ฐ„ ๋™์•ˆ์˜ ์—ด์‘๋‹ต ์‹œํ—˜ ํ›„ ์ดˆ๊ธฐ ์—ด์šฉ๋Ÿ‰์ด ์ผ์ •ํ•˜์ง€ ์•Š์€ ๊ฒƒ์„ ๊ณ ๋ คํ•˜์—ฌ ์ดˆ๊ธฐ 12์‹œ๊ฐ„ ์˜จ๋„ ๋ฐ์ดํ„ฐ๋ฅผ ์ œ์™ธํ•˜๊ณ  Eq. (1)์„ ์ด์šฉํ•˜์—ฌ ์ง€๋ฐ˜์˜ ์—ด์ „๋„๋„๋ฅผ ์‚ฐ์ •ํ•˜์˜€๋‹ค. Fig. 4๋Š” U, W ๊ทธ๋ฆฌ๊ณ  2U์žํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ ์ด์šฉ์‹œ ์—ด์‘๋‹ต ์‹คํ—˜ ์‹œ๊ฐ„์— ๋”ฐ๋ฅธ ์ˆœํ™˜์ˆ˜์˜ ํ‰๊ท  ์˜จ๋„ ๋ณ€ํ™”๋ฅผ ๋‚˜ํƒ€๋‚ธ๋‹ค. U, W ๊ทธ๋ฆฌ๊ณ  2U์žํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ ์ด์šฉ์— ๋”ฐ๋ฅธ ์ง€๋ฐ˜์˜ ์—ด์ „๋„๋„๋Š” ๊ฐ๊ฐ 2.13, 2.15, 2.17W/mยทK ๊ฐ’์„ ๋ณด์˜€๋‹ค. ์—ด๊ตํ™˜๊ธฐ ํ˜•ํƒœ๋ณ„ ์ง€๋ฐ˜์˜ ์—ด์ „๋„๋„๊ฐ€ 1โˆผ2% ๋ฒ”์œ„ ๋‚ด์—์„œ ์ฐจ์ด๋ฅผ ๋ณด์˜€์œผ๋‚˜ ์ด๋Š” ์ง€๋ฐ˜์˜ ์ดˆ๊ธฐ์˜จ๋„๊ฐ€ ์™„์ „ํžˆ ์ผ์น˜ํ•˜์ง€ ์•Š์•˜์œผ๋ฉฐ ์—ด๊ตํ™˜๊ธฐ ํ˜•ํƒœ ์ฐจ์ด์— ๊ธฐ์ธํ•œ ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

PIC6BCC.jpg

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(a) Temperature Distribution vs. Time

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(b) Temperature Distribution vs. lnt

Fig. 4. Fluid Average Temperature Distribution During the TRT (Thermal Response Test)

4. ํ˜„์žฅ ์—ด์„ฑ๋Šฅ ์‹คํ—˜ ๊ฒฐ๊ณผ

์—ด์‘๋‹ต ์‹คํ—˜ ํ›„ ๋™์ผํ•œ ์ง€๋ฐ˜ ์กฐ๊ฑดํ•˜์—์„œ U, W, 2U ๊ทธ๋ฆฌ๊ณ  ์ฝ”์ผํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ๊ฐ€ ์„ค์น˜๋œ ๋ณด์–ดํ™€์—์„œ ํ˜„์žฅ ์—ด์„ฑ๋Šฅ ์‹คํ—˜์„ ์‹ค์‹œํ•˜์˜€๋‹ค. ๋ƒ‰๋ฐฉ ๊ฐ€๋™์‹œ๋ฅผ ๋ชจ์‚ฌํ•˜๊ธฐ ์œ„ํ•ด ์ง€๋ฐ˜์œผ๋กœ ํˆฌ์ž…๋˜๋Š” ์˜จ๋„๋Š” 31ยฐC๋กœ ์ผ์ •ํ•˜๊ฒŒ ์ œ์–ดํ•˜์˜€์œผ๋ฉฐ 100์‹œ๊ฐ„ ์—ฐ์† ์šด์˜ ์กฐ๊ฑด๊ณผ ๋ถ€๋ถ„์šด์˜์กฐ๊ฑด(8์‹œ๊ฐ„ ์šด์šฉ, 16์‹œ๊ฐ„ ๋Œ€๊ธฐ)์œผ๋กœ 5์ผ๊ฐ„ ์ง„ํ–‰ํ•˜์—ฌ ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ ํ˜•ํƒœ์— ๋”ฐ๋ฅธ ์—ด๊ตํ™˜์œจ์„ ์‚ฐ์ •ํ•˜์˜€๋‹ค. ์—ด์‘๋‹ต ์‹คํ—˜๊ณผ ๋งˆ์ฐฌ๊ฐ€์ง€๋กœ ๋‚œ๋ฅ˜ ์กฐ๊ฑด์„ ํ˜•์„ฑํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ์œ ๋Ÿ‰์€ 6โˆผ8lpm ๊ฐ’์œผ๋กœ ์ œ์–ดํ•˜์˜€์œผ๋ฉฐ ์ž…์ถœ๊ตฌ ์˜จ๋„์™€ ์œ ๋Ÿ‰์€ 10๋ถ„ ๊ฐ„๊ฒฉ์œผ๋กœ ์‹ค์‹œ๊ฐ„์œผ๋กœ ๊ณ„์ธก ์ €์žฅํ•˜์˜€๋‹ค.

4.1 100์‹œ๊ฐ„ ๋ƒ‰๋ฐฉ ๊ฐ€๋™ ์—ฐ์† ์šด์ „ ์‹คํ—˜ ๊ฒฐ๊ณผ

U, W, 2U ๊ทธ๋ฆฌ๊ณ  ์ฝ”์ผํ˜• ์ง€์ค‘ ์—ดํ™˜๊ธฐ๊ธฐ ์„ค์น˜๋œ ๋ณด์–ดํ™€์— 100์‹œ๊ฐ„ ๋™์•ˆ ์—ฐ์†์œผ๋กœ ์—ด์„ฑ๋Šฅ ์‹คํ—˜์„ ์ˆ˜ํ–‰ํ•œ ํ›„ Eq. (2)๋ฅผ ์ด์šฉํ•˜์—ฌ 100์‹œ๊ฐ„ ํ‰๊ท  ์—ด๊ตํ™˜์œจ ๊ฐ’์„ ์‚ฐ์ •ํ•˜์˜€๋‹ค. ๋น„๋ก ์ฝ”์ผํ˜•์˜ ๊ฒฝ์šฐ ๊นŠ์ด์™€ ๋ณด์–ดํ™€ ๋‹จ๋ฉด์ ์˜ ๋„“์ด๊ฐ€ ๋‚˜๋จธ์ง€ ์—ด๊ตํ™˜๊ธฐ์™€ ๋‹ค๋ฅด๋‹ค ํ•˜๋”๋ผ๋„ ์—ด์„ฑ๋Šฅ ์‹คํ—˜์— ์˜ํ•ด ์–ป์–ด์ง€๋Š” ์—ด๊ตํ™˜์œจ์„ ๋ณด์–ดํ™€์˜ ๊ธธ์ด๋กœ ๋‚˜๋ˆˆ ๋‹จ์œ„ ๊นŠ์ด๋‹น ์—ด๊ตํ™˜์œจ๋กœ ๋น„๊ตํ•˜์˜€๋‹ค. ๋ณด์–ดํ™€ ๋‚ด์˜ ๋‹ค๋ฅธ ํ˜•ํƒœ์˜ ์—ด๊ตํ™˜๊ธฐ ๋ฐ ๋ณด์–ดํ™€ ๋ฉด์  ๋“ฑ์€ ๋ณด์–ดํ™€์˜ ์—ด์ €ํ•ญ์— ์˜ํ–ฅ์„ ์ฃผ์–ด ์ž…์ถœ๊ตฌ์˜ ์˜จ๋„์ฐจ ๊ฒฐ๊ณผ์— ์˜ํ–ฅ์„ ์ฃผ๋ฏ€๋กœ Eq. (2)๋กœ๋ถ€ํ„ฐ ์‚ฐ์ •๋œ ์ด ์—ด๊ตํ™˜์œจ ๊ฐ’์— ์ด๋ฏธ ๋ฐ˜์˜๋˜์—ˆ๋‹ค๊ณ  ํ•  ์ˆ˜ ์žˆ๋‹ค. U์žํ˜• ์—ด๊ตํ™˜๊ธฐ ์ด์šฉ์‹œ 35.71W/m, W์žํ˜• ์—ด๊ตํ™˜๊ธฐ ์ด์šฉ์‹œ 40.76W/m, 2U์žํ˜• ์ด์šฉ์‹œ๋Š” 39.03W/m ๊ทธ๋ฆฌ๊ณ  ์ฝ”์ผํ˜• ์—ด๊ตํ™˜๊ธฐ ์ด์šฉ์‹œ 76.8W/m ์˜ ์—ด๊ตํ™˜์œจ์„ ๋ณด์˜€๋‹ค. W์žํ˜•๊ณผ 2U์žํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ ์ด์šฉ์‹œ U์žํ˜•์— ๋น„ํ•ด 10โˆผ15% ์ •๋„ ์—ด๊ตํ™˜์œจ์ด ์ƒ์Šน๋˜๋Š” ๊ฒƒ์„ ํ™•์ธํ•  ์ˆ˜ ์žˆ์—ˆ๋‹ค. ์ด๋Š” W์žํ˜•๊ณผ 2U์žํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ๋Š” U์žํ˜•์— ๋น„ํ•ด ๋” ๋„“์€ ์—ด๊ตํ™˜ ์ ‘์ด‰๋ฉด์ ์„ ๊ฐ€์ง€๊ธฐ ๋–„๋ฌธ์ธ ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋˜๋ฉฐ W์žํ˜•์ด 2U์žํ˜•๋ณด๋‹ค 4โˆผ5% ๋†’์€ ์—ด๊ตํ™˜์œจ ๊ฐ’์„ ๋ณด์˜€์œผ๋‚˜ ์„œ๋กœ ๊ฐ„์— ์ƒ๋Œ€์ ์ธ ์šฐ์›”์„ฑ์„ ๊ฐ€์ง€์ง€๋Š” ์•Š๋Š” ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค. ์ฝ”์ผํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ ์ด์šฉ์‹œ ๋‚˜๋จธ์ง€ ํƒ€์ž…๋“ค๋ณด๋‹ค ๋ณด์–ดํ™€ ๋‹จ์œ„ ๊ธธ์ด๋‹น ์—ด๊ตํ™˜์œจ์€ ๋Œ€๋žต 2๋ฐฐ ์ •๋„ ๋†’์€ ์—ด๊ตํ™˜์œจ์„ ๋‚˜ํƒ€๋‚ด์—ˆ๋Š”๋ฐ ์ฝ”์ผํ˜• ์—ด๊ตํ™˜๊ธฐ์˜ ์ด ๊ธธ์ด๊ฐ€ ๋Œ€๋žต 350m์ธ ๊ฒƒ์„ ๊ฐ์•ˆํ•˜๋ฉด ๊ทธ๋งŒํผ ๊ทธ๋ผ์šฐํŠธ์™€์˜ ์—ด์ ‘์ด‰ ๋ฉด์ ์ด ๋„“๊ธฐ์— ๋†’์€ ์—ด๊ตํ™˜์œจ ๊ฐ’์„ ๊ฐ€์ง€๋Š” ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค. ๊ธฐ์กด์˜ ์—ฐ๊ตฌ ๊ฒฐ๊ณผ์—์„œ๋„ ์ฝ”์ผํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ๋Š” ์ผ๋ฐ˜ ๋ผ์ธํ˜•์— ๋น„ํ•ด ์—ด๊ตํ™˜ ๋Šฅ๋ ฅ์ด ์šฐ์ˆ˜ํ•œ ๊ฒƒ์œผ๋กœ ์•Œ๋ ค์ ธ ์žˆ๋‹ค(Cui et al., 2011; Man et al., 2010). ํ•˜์ง€๋งŒ ์ฝ”์ผํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ๋Š” ์ผ๋ฐ˜ ๋ผ์ธํ˜•์— ๋น„ํ•ด ๋ณด์–ดํ™€ ๋ฉด์ ์ด ํฌ๊ฒŒ ์†Œ์š”๋˜๊ธฐ์— ์—๋„ˆ์ง€ ํŒŒ์ผ๊ณผ ๊ฐ™์ด ๋ณด์–ดํ™€ ๊นŠ์ด์™€ ์ง๊ฒฝ์ด ์ผ์ •ํ•˜๊ฒŒ ๊ณ ์ •๋œ ์กฐ๊ฑด์—์„œ ์ ์šฉํ•  ๊ฒฝ์šฐ ๋ณด๋‹ค ์šฐ์ˆ˜ํ•œ ์„ฑ๋Šฅ์„ ๋‚˜ํƒ€๋‚ผ ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค. Fig. 5๋Š” 100์‹œ๊ฐ„ ์—ด์„ฑ๋Šฅ ์‹คํ—˜์— ๋”ฐ๋ฅธ ์—ด๊ตํ™˜์œจ์„ ๋ณด์—ฌ์ฃผ๊ณ  ์žˆ๋‹ค. ์—ด๊ตํ™˜์œจ ๊ฐ’์ด ์ƒ๋Œ€์ ์œผ๋กœ ์ž‘์€ U, W ๊ทธ๋ฆฌ๊ณ  2U์ž์™€ ๊ฐ™์€ ๋ผ์ธํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ๋Š” ์‹คํ—˜ ์‹œ์ž‘ ํ›„ ๋Œ€๋žต 1000๋ถ„์ด ์ง€๋‚œ ํ›„์— ์—ด๊ตํ™˜์œจ ๊ฐ’์ด ๊ฑฐ์˜ ์ผ์ •ํ•ด์ง€๋Š” ์ •์ƒ์ƒํƒœ์— ๋„๋‹ฌํ–ˆ์Œ์„ ์•Œ ์ˆ˜ ์žˆ์—ˆ๋‹ค. ํ•˜์ง€๋งŒ ์ฝ”์ผํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ์˜ ๊ฒฝ์šฐ ์‹คํ—˜ ํ›„ ๋Œ€๋žต 3000๋ถ„ ์ •๋„ ์ง€๋‚œ ํ›„ ์ •์ƒ์ƒํƒœ์— ๋„๋‹ฌํ•จ์„ ๋ณด์˜€๋Š”๋ฐ ์ด๋Š” ์ฝ”์ผํ˜•์˜ ๊ฒฝ์šฐ ๋ณด์–ดํ™€์˜ ์ง๊ฒฝ์ด ์ปค ๋ณด์–ดํ™€ ์ž์ฒด๊ฐ€ ๋ณด์œ ํ•œ ์—ด์šฉ๋Ÿ‰์ด ํฌ๊ธฐ์— ๊ทธ๋งŒํผ ๋ผ์ธํ˜• ์—ด๊ตํ™˜๊ธฐ๋ณด๋‹ค ์ •์ƒ์ƒํƒœ์— ๋„๋‹ฌํ•˜๋Š” ์‹œ๊ฐ„์ด ์˜ค๋ž˜ ๊ฑธ๋ฆฐ๋‹ค๋Š” ๊ฒƒ์„ ์•Œ ์ˆ˜ ์žˆ๋‹ค.

PIC7047.jpg

Fig. 5. Heat Exchange Rate for 100 Hours Under the Continuous Operation

4.2 ๋ƒ‰๋ฐฉ ๊ฐ€๋™ ๋ถ€๋ถ„ ์šด์ „ ์‹คํ—˜ ๊ฒฐ๊ณผ

์‹ค์ œ ์ง€์—ด์‹œ์Šคํ…œ ๊ฐ€๋™์‹œ ํ˜„์‹ค์ ์œผ๋กœ ์—ฐ์† ์šด์ „ ์กฐ๊ฑด๋ณด๋‹ค๋Š” ๋ฒ•์ • ๊ทผ๋กœ์‹œ๊ฐ„์ธ 8์‹œ๊ฐ„ ์šด์ „ 16์‹œ๊ฐ„ ํœด์ง€๋ฅผ ๊ฐ€์ •ํ•œ ๋ถ€๋ถ„ ์šด์ „ ์กฐ๊ฑด์œผ๋กœ 5์ผ๊ฐ„ ์—ด์„ฑ๋Šฅ ์‹คํ—˜์„ ์ˆ˜ํ–‰ํ•˜์˜€๋‹ค. ์—ฐ์† ์šด์ „์กฐ๊ฑด ๊ฒฐ๊ณผ๋กœ๋ถ€ํ„ฐ W์žํ˜•๊ณผ ์ฝ”์ผํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ์˜ ๋ณด์–ดํ™€ ๋‹จ์œ„ ๊ธธ์ด๋‹น ์—ด๊ตํ™˜์œจ์ด ์šฐ์ˆ˜ํ•˜๊ฒŒ ๋‚˜ํƒ€๋‚ฌ๊ธฐ์— ๋ถ€๋ถ„ ์šด์ „ ์กฐ๊ฑด์˜ ์—ด์„ฑ๋Šฅ ์‹คํ—˜์—์„œ๋Š” W์žํ˜•๊ณผ ์ฝ”์ผํ˜• ์—ด๊ตํ™˜๊ธฐ์— ๋Œ€ํ•ด ์‹ค์‹œํ•˜์˜€์œผ๋ฉฐ ์œ ์ž…์ˆ˜ ์˜จ๋„ ๋ฐ ์œ ๋Ÿ‰ ๋“ฑ์˜ ์‹คํ—˜ ์กฐ๊ฑด์€ ์—ฐ์† ์šด์ „๊ณผ ๋™์ผํ•˜์˜€๋‹ค. Fig. 6์€ W์žํ˜•๊ณผ ์ฝ”์ผํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ ์ด์šฉ์‹œ 5์ผ๊ฐ„ ๋ถ€๋ถ„ ์šด์ „์— ๋”ฐ๋ฅธ ์—ด๊ตํ™˜์œจ์„ ๋‚˜ํƒ€๋‚ธ๋‹ค. 5์ผ๊ฐ„์˜ ๋ถ€๋ถ„ ์šด์ „ ์‹คํ—˜ ๊ฒฐ๊ณผ W์žํ˜• ์—ด๊ตํ™˜๊ธฐ ์ด์šฉ์‹œ ํ‰๊ท  ์—ด๊ตํ™˜์œจ ๊ฐ’์€ 54.16W/m, ์ฝ”์ผํ˜• ์—ด๊ตํ™˜๊ธฐ ์ด์šฉ์‹œ๋Š” ํ‰๊ท  103W/m์˜ ์—ด๊ตํ™˜์œจ ๊ฐ’์„ ๋ณด์˜€๋‹ค. ๋ถ€๋ถ„ ์šด์ „ ์กฐ๊ฑด์ด ์—ฐ์† ์šด์ „ ์กฐ๊ฑด์— ๋น„ํ•ด 30โˆผ40% ๊ฐ€๋Ÿ‰ ๋†’์€ ์—ด๊ตํ™˜ ํšจ์œจ์„ ์œ ๋ฐœํ•˜๋Š” ๊ฒƒ์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ์ด๋Š” ์—ฐ์† ์šด์ „ ์กฐ๊ฑด์€ ๋ถ€๋ถ„ ์šด์ „ ์กฐ๊ฑด์— ๋น„ํ•ด ์ง€๋ฐ˜์œผ๋กœ ์—ด์ด ๊ณ„์† ์ถ•์ ๋˜๊ธฐ์— ์—ด์ „๋‹ฌ ํšจ์œจ ๊ฐ์†Œ๊ฐ€ ํฌ๊ฒŒ ๋‚˜ํƒ€๋‚œ ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

4.3 ๋ƒ‰๋ฐฉ ๊ฐ€๋™ 6๊ฐœ์›” ์žฅ๊ธฐ์„ฑ๋Šฅ ์˜ˆ์ธก ๊ฒฐ๊ณผ

100์‹œ๊ฐ„ ์—ฐ์† ์šด์ „ ์‹คํ—˜ ๊ฒฐ๊ณผ์™€ 5์ผ ๋ถ€๋ถ„ ์šด์ „ ์‹คํ—˜ ๊ฒฐ๊ณผ ์‚ฐ์ถœ๋œ ์—ด๊ตํ™˜์œจ ๊ฐ’์„ ๊ทผ๊ฑฐ๋กœ Figs. 5 and 7์˜ ์ถ”์„ธ์„  ์‹์„ ์ด์šฉํ•˜์—ฌ ํšŒ๊ท€๋ถ„์„์„ ํ†ตํ•ด 6๊ฐœ์›” ๋ƒ‰๋ฐฉ ๊ฐ€๋™์‹œ ์—ด๊ตํ™˜์œจ ๊ฐ’์„ ์ถ”์ •ํ•˜์˜€๋‹ค. ๋ฌผ๋ก  ์ผ๋ฐ˜์ ์ธ ์ƒ์—…์šฉ ๊ฑด๋ฌผ์ด๋ผ ํ• ์ง€๋ผ๋„ ํ˜„์‹ค์ ์œผ๋กœ 6๊ฐœ์›” ๋™์•ˆ ๋ƒ‰๋ฐฉ ๊ฐ€๋™์€ ๋ถˆ๊ฐ€๋Šฅํ•˜์ง€๋งŒ ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ๋ถ€๋ถ„ ์šด์ „ ๋ฐ ์—ฐ์† ์šด์ „์˜ ์žฅ๊ธฐ๊ฐ„ ๋น„๊ต ๋ถ„์„์„ ์œ„ํ•˜์—ฌ 6๊ฐœ์›” ๋™์•ˆ์˜ ๋ƒ‰๋ฐฉ ๊ฐ€๋™ ์กฐ๊ฑดํ•˜์— ์—ด์„ฑ๋Šฅ ์˜ˆ์ธก์„ ์‹ค์‹œํ•˜์˜€๋‹ค. ๊ณ„์ธก๋œ ์‹คํ—˜๊ฐ’์„ ๊ทผ๊ฑฐ๋กœ ์‚ฐ์ถœ๋œ ์ถ”์„ธ์„  ์‹์˜ PIC7153.gif๊ฐ’์€ ๋ชจ๋‘ 0.9 ์ด์ƒ์œผ๋กœ ๋ณธ ํšŒ๊ท€๋ถ„์„์„ ํ†ตํ•œ 3๊ฐœ์›” ๋™์•ˆ์˜ ์—ด๊ตํ™˜์œจ ๊ฐ’์„ ์˜ˆ์ธกํ•˜๋Š”๋ฐ ํฐ ์˜ค์ฐจ ์—†์ด ์‚ฌ์šฉ๋  ์ˆ˜ ์žˆ๋Š” ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค. ๋ถ€๋ถ„ ๊ฐ€๋™์˜ ๊ฒฝ์šฐ W์žํ˜•๊ณผ ์ฝ”์ผํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ์— ๋Œ€ํ•ด์„œ๋งŒ ์ˆ˜ํ–‰ํ•˜์˜€๊ธฐ์— ๋‘ ๊ฐ€์ง€ ํ˜•ํƒœ์— ๋Œ€ํ•ด์„œ๋งŒ 6๊ฐœ์›” ์žฅ๊ธฐ์„ฑ๋Šฅ์„ ์˜ˆ์ธกํ•˜์˜€๋‹ค. Fig. 7์€ 5์ผ๊ฐ„์˜ ํ‰๊ท  ์—ด๊ตํ™˜์œจ ๊ฐ’์„ ์ด์šฉํ•œ ์ถ”์„ธ์„  ์‹์„ ๋ณด์—ฌ์ฃผ๊ณ  ์žˆ๋‹ค. Fig. 8์€ ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ์˜ 6๊ฐœ์›” ์—ฐ์† ์šด์ „์‹œ ์˜ˆ์ƒ๋˜๋Š” ์—ด๊ตํ™˜์œจ์„ ๋‚˜ํƒ€๋‚ด๊ณ  ์žˆ์œผ๋ฉฐ Fig. 9๋Š” W์žํ˜•๊ณผ ์ฝ”์ผํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ์˜ 6๊ฐœ์›” ๋ถ€๋ถ„ ์šด์ „์‹œ ์˜ˆ์ธก๋œ ์—ด๊ตํ™˜์œจ์„ ๋ณด์—ฌ์ฃผ๊ณ  ์žˆ๋‹ค. Table 2๋Š” ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ ํ˜•ํƒœ๋ณ„ ์‹คํ—˜๊ฒฐ๊ณผ์™€ 6๊ฐœ์›” ๊ฐ„ ์˜ˆ์ธก๋œ ์—ด๊ตํ™˜์œจ์„ ์š”์•ฝํ•˜์—ฌ ๋ณด์—ฌ์ฃผ๊ณ  ์žˆ๋‹ค. ์‹œ๊ฐ„์ด ์ง€๋‚ ์ˆ˜๋ก ์ง€๋ฐ˜์œผ๋กœ ๋ฐฉ์ถœ๋˜๋Š” ์—ด๋Ÿ‰์ด ์ถ•์ ๋˜๊ธฐ์— ๊ทธ๋งŒํผ ์—ด๊ตํ™˜์œจ ๊ฐ’์ด ๊ฐ์†Œ๋˜๋Š” ๊ฒƒ์„ ์•Œ ์ˆ˜ ์žˆ๋‹ค. 6๊ฐœ์›” ์˜ˆ์ธก์—์„œ๋„ ๋ถ€๋ถ„ ์šด์ „ ์กฐ๊ฑด์ด ์—ฐ์† ์šด์ „ ์กฐ๊ฑด์— ๋น„ํ•ด 30โˆผ40 % ๊ฐ€๋Ÿ‰ ๋†’์€ ์—ด๊ตํ™˜ ํšจ์œจ์„ ์œ ๋ฐœํ•˜๋Š” ๊ฒƒ์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ์ผ๋ฐ˜ ์ˆ˜์ง ๋ฐ€ํํ˜•์˜ ์—ด๊ตํ™˜์œจ์ด 40โˆผ70W/m ์ธ ๊ฒƒ์„ ๊ฐ์•ˆํ•  ๋•Œ(European Geothermal Energy Council, 2008) ๋ณธ ์—ฐ๊ตฌ์—์„œ ๊ณ„์ธก๋œ ์—ด๊ตํ™˜์œจ ๊ฐ’์€ ์ฝ”์ผํ˜•์„ ์ œ์™ธํ•˜๊ณ ๋Š” ๋‹ค์†Œ ๋‚ฎ์€ ๊ฐ’์„ ๋‚˜ํƒ€๋‚ด๊ณ  ์žˆ๋‹ค. ์ด๋Š” ์„ค์น˜๋œ ๋ณด์–ดํ™€ ์ˆ˜์ง๊นŠ์ด๊ฐ€ 30โˆผ50m๋กœ ์–•๊ณ  ์ง€์ค‘ ์—ด์ „๋„๋„๊ฐ€ 2.15W/mยทK ๊ทผ์ฒ˜๋กœ ๋‹ค์†Œ ๋‚ฎ๊ฒŒ ์ธก์ •๋˜์—ˆ๊ธฐ ๋•Œ๋ฌธ์ธ ๊ฒƒ์œผ๋กœ ์ถ”์ •๋œ๋‹ค.

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Fig. 6. Heat Exchange Rate for Five Days Under the Intermittent Operation

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Fig. 7. Heat Exchange Rate by Regression Analysis

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Fig. 8. Heat Exchange Rate for Sixth Months Under the Continuous Operation Condition

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Fig. 9. Heat Exchange Rate for Sixth Months Under the Intermittent Operation Condition

5. ๊ฒฐ ๋ก 

๋ณธ ๋…ผ๋ฌธ์—์„œ๋Š” ๋งค๋ฆฝ์ง€ ์ง€๋ฐ˜์œผ๋กœ ๊ตฌ์„ฑ๋œ ์ธ์ฒœ๊ตญ์ œ๊ณตํ•ญ ์ œ 2์—ฌ๊ฐํ„ฐ๋ฏธ๋„์ด ๊ฑด์„ค๋  ๋ถ€์ง€์— U, W, 2U ๊ทธ๋ฆฌ๊ณ  ์ฝ”์ผํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ๋ฅผ ์„ค์น˜ํ•˜์—ฌ ํ˜„์žฅ ์—ด์‘๋‹ต ๋ฐ ์—ด์„ฑ๋Šฅ ์‹คํ—˜์„ ์‹ค์‹œํ•˜์—ฌ ์ง€๋ฐ˜์˜ ์—ด์ „๋„๋„ ๋ฐ ์—ด๊ตํ™˜์œจ์„ ์‚ฐ์ •ํ•˜์˜€๋‹ค. ๋ณธ ์—ฐ๊ตฌ๋ฅผ ํ†ตํ•ด ๋‹ค์Œ๊ณผ ๊ฐ™์€ ๊ฒฐ๋ก ์„ ๋„์ถœํ•˜์˜€๋‹ค.

Table 2. Summary of TPT (Thermal Performance Test) Results

GHE

Heat exchange rate

under the continuous operation (W/m)

Heat exchange rate

under the intermittent operation (W/m)

100hr average

6-month average

1day

2day

3day

4day

5day

5-day

average

6-month

average

U

35.74

24.10

-

-

-

-

-

-

-

W

40.76

27.11

58.7

55.6

53.6

52.2

50.7

54.2

40.63

2U

39.03

27.62

-

-

-

-

-

-

-

Coil

76.8

32.84

117.5

107.1

100.6

96.4

94

103.1

65.6

(1)U, W ๊ทธ๋ฆฌ๊ณ  2U์žํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ ์ด์šฉ์— ๋”ฐ๋ฅธ ์ง€๋ฐ˜์˜ ์—ด์ „๋„๋„๋Š” ๊ฐ๊ฐ 2.13, 2.15, 2.17W/mยทK ๊ฐ’์„ ๋ณด์˜€๋‹ค. ์—ด๊ตํ™˜๊ธฐ ํ˜•ํƒœ๋ณ„ ์ง€๋ฐ˜์˜ ์—ด์ „๋„๋„๊ฐ€ 1โˆผ2% ๋ฒ”์œ„ ๋‚ด์—์„œ ์ฐจ์ด๋ฅผ ๋ณด์˜€์œผ๋‚˜ ์ด๋Š” ์ง€๋ฐ˜์˜ ์ดˆ๊ธฐ์˜จ๋„๊ฐ€ ์™„์ „ํžˆ ์ผ์น˜ํ•˜์ง€ ์•Š์•˜๊ณ  ์—ด๊ตํ™˜๊ธฐ ํ˜•ํƒœ์˜ ์ฐจ์ด์— ๊ธฐ์ธํ•œ ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค. ๋”ฐ๋ผ์„œ ์—ด๊ตํ™˜๊ธฐ ํ˜•ํƒœ์™€ ๊ด€๊ณ„์—†์ด ๋ฌดํ•œ ์„ ํ˜• ์—ด์› ๋ชจ๋ธ์„ ์ ์šฉํ•˜์—ฌ ์—ด์‘๋‹ต ์‹คํ—˜์„ ํ†ตํ•ด ์ง€๋ฐ˜์˜ ์—ด์ „๋„๋„ ์ถ”์ •์ด ๊ฐ€๋Šฅํ•˜๋‹ค.

(2)U, W, 2U ๊ทธ๋ฆฌ๊ณ  ์ฝ”์ผํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ๊ฐ€ ์„ค์น˜๋œ ๋ณด์–ดํ™€์— 100์‹œ๊ฐ„ ๋™์•ˆ ์—ฐ์†์œผ๋กœ ๋ƒ‰๋ฐฉ ์šด์ „ ์กฐ๊ฑด์œผ๋กœ ์—ด์„ฑ๋Šฅ ์‹คํ—˜์„ ์ˆ˜ํ–‰ํ•œ ํ›„ ํ‰๊ท  ์—ด๊ตํ™˜์œจ ๊ฐ’์„ ์‚ฐ์ •ํ•œ ๊ฒฐ๊ณผ U์žํ˜• ์—ด๊ตํ™˜๊ธฐ ์ด์šฉ์‹œ 35.71W/m, W์žํ˜• ์—ด๊ตํ™˜๊ธฐ ์ด์šฉ์‹œ 40.76W/m, 2U์žํ˜• ์ด์šฉ์‹œ๋Š” 39.03W/m ๊ทธ๋ฆฌ๊ณ  ์ฝ”์ผํ˜• ์—ด๊ตํ™˜๊ธฐ ์ด์šฉ์‹œ 76.8W/m์˜ ์—ด๊ตํ™˜์œจ์„ ๋ณด์˜€๋‹ค. W์žํ˜•๊ณผ 2U์žํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ ์ด์šฉ์‹œ U์žํ˜•์— ๋น„ํ•ด 10โˆผ15% ์ •๋„ ์—ด๊ตํ™˜์œจ์ด ์ƒ์Šน๋˜๋Š” ๊ฒƒ์„ ํ™•์ธํ•  ์ˆ˜ ์žˆ์—ˆ๋‹ค. ์ด๋Š” W์žํ˜•๊ณผ 2U์žํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ๋Š” U์žํ˜•์— ๋น„ํ•ด ๋” ๋„“์€ ์—ด๊ตํ™˜ ์ ‘์ด‰๋ฉด์ ์„ ๊ฐ€์ง€๊ธฐ ๋•Œ๋ฌธ์ธ ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋˜๋ฉฐ W์žํ˜•์ด 2U์žํ˜•๋ณด๋‹ค 4โˆผ5% ๋†’์€ ์—ด๊ตํ™˜์œจ ๊ฐ’์„ ๋ณด์˜€์œผ๋‚˜ ์„œ๋กœ ๊ฐ„์— ์ƒ๋Œ€์ ์ธ ์šฐ์›”์„ฑ์„ ๊ฐ€์ง€์ง€๋Š” ์•Š๋Š” ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค. ํ•˜์ง€๋งŒ ์ผ๋ฐ˜์ ์ธ U์žํ˜• ์—ด๊ตํ™˜๊ธฐ๋Š” 30โˆผ40mm ์ง๊ฒฝ์˜ HDPE (high densitypPolyethylene) ํŒŒ์ดํ”„๊ฐ€ ์‚ฌ์šฉ๋˜๋ฉฐ 150mm์˜ ๋ณด์–ดํ™€ ์ง๊ฒฝ์— 30mm ์ด์ƒ์˜ W์žํ˜• ์—ด๊ตํ™˜๊ธฐ๋ฅผ ์„ค์น˜ํ•˜๊ธฐ์—๋Š” ์‹œ๊ณต์ƒ ์–ด๋ ค์›€์ด ํด ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค. ๋”ฐ๋ผ์„œ 20โˆผ25mm ์ง๊ฒฝ์˜ W์žํ˜• ์—ด๊ตํ™˜๊ธฐ์™€ 30โˆผ40mm ์ง๊ฒฝ์˜ U์žํ˜• ์—ด๊ตํ™˜๊ธฐ ์ ์šฉ์‹œ ์ƒ๋Œ€์ ์ธ ์—ด์„ฑ๋Šฅ์„ ๋น„๊ต ๋ถ„์„ํ•˜๋Š” ์—ฐ๊ตฌ๊ฐ€ ํ•„์š”ํ•  ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค. ๋˜ํ•œ ์ฝ”์ผํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ ์ด์šฉ์‹œ ๋‚˜๋จธ์ง€ ํƒ€์ž…๋“ค๋ณด๋‹ค ๋Œ€๋žต 2๋ฐฐ ์ •๋„ ๋†’์€ ์—ด๊ตํ™˜์œจ์„ ๋‚˜ํƒ€๋‚ด์—ˆ๋Š”๋ฐ ์ฝ”์ผํ˜• ์—ด๊ตํ™˜๊ธฐ์˜ ์ด ๊ธธ์ด๊ฐ€ ๋Œ€๋žต 350m ์ธ ๊ฒƒ์„ ๊ฐ์•ˆํ•˜๋ฉด ๊ทธ๋งŒํผ ๊ทธ๋ผ์šฐํŠธ์™€์˜ ์—ด์ ‘์ด‰ ๋ฉด์ ์ด ๋„“๊ธฐ์— ๋†’์€ ์—ด๊ตํ™˜์œจ ๊ฐ’์„ ๊ฐ€์ง€๋Š” ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

(3)W์žํ˜•๊ณผ ์ฝ”์ผํ˜• ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ๋ฅผ ์ด์šฉํ•˜์—ฌ 5์ผ๊ฐ„์˜ ๋ถ€๋ถ„ ์šด์ „ ์‹คํ—˜ ๊ฒฐ๊ณผ W์žํ˜• ์—ด๊ตํ™˜๊ธฐ ์ด์šฉ์‹œ ํ‰๊ท  ์—ด๊ตํ™˜์œจ ๊ฐ’์€ 54.16W/m, ์ฝ”์ผํ˜• ์—ด๊ตํ™˜๊ธฐ ์ด์šฉ์‹œ๋Š” ํ‰๊ท  103W/m์˜ ์—ด๊ตํ™˜์œจ ๊ฐ’์„ ๋ณด์˜€๋‹ค. ์ฆ‰ ๋ถ€๋ถ„ ์šด์ „ ์กฐ๊ฑด์ด ์—ฐ์† ์šด์ „ ์กฐ๊ฑด์— ๋น„ํ•ด 30โˆผ40% ๊ฐ€๋Ÿ‰ ๋†’์€ ์—ด๊ตํ™˜ ํšจ์œจ์„ ์œ ๋ฐœํ•˜๋Š” ๊ฒƒ์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ์ด๋Š” ์—ฐ์† ์šด์ „ ์กฐ๊ฑด์€ ๋ถ€๋ถ„ ์šด์ „ ์กฐ๊ฑด์— ๋น„ํ•ด ์ง€๋ฐ˜์œผ๋กœ ์—ด์ด ๊ณ„์† ์ถ•์ ๋˜๊ธฐ์— ์—ด์ „๋‹ฌ ํšจ์œจ ๊ฐ์†Œ๊ฐ€ ํฌ๊ฒŒ ๋‚˜ํƒ€๋‚œ ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค. ๋˜ํ•œ ๊ณ„์ธก๋œ ๊ฐ’์„ ๊ทผ๊ฑฐ๋กœ ์ถ”์„ธ์„  ์‹์„ ์‚ฐ์ถœํ•˜์—ฌ 6๊ฐœ์›” ์—ด๊ตํ™˜์œจ ๊ฐ’์„ ์ถ”์ •ํ•œ ๊ฒฐ๊ณผ U์žํ˜• ์—ฐ์† ์šด์ „์‹œ 24.10W/m, W์žํ˜•์˜ ๊ฒฝ์šฐ ์—ฐ์† ์šด์ „: 29.19W/m, ๋ถ€๋ถ„ ์šด์ „: 40.63W/m ์˜ ๊ฐ’์„ ๋‚˜ํƒ€๋ƒˆ๋‹ค. ๋˜ํ•œ ์ฝ”์ผํ˜•์˜ ๊ฒฝ์šฐ 6๊ฐœ์›” ์—ฐ์† ์šด์ „์‹œ 32.84W/m, ๋ถ€๋ถ„ ์šด์ „์‹œ๋Š” 65.58W/m ๊ฐ’์„ ๋‚˜ํƒ€๋ƒˆ๋‹ค. ์‹œ๊ฐ„์ด ์ง€๋‚ ์ˆ˜๋ก ์ง€๋ฐ˜์œผ๋กœ์˜ ๋ฐฉ์ถœ๋˜๋Š” ์—ด๋Ÿ‰์ด ์ถ•์ ๋˜๊ธฐ์— ๊ทธ๋งŒํผ ์—ด๊ตํ™˜์œจ ๊ฐ’์ด ๊ฐ์†Œ๋˜๋Š” ๊ฒƒ์„ ์•Œ ์ˆ˜ ์žˆ๋‹ค. 6๊ฐœ์›” ์˜ˆ์ธก์—์„œ๋„ ๋ถ€๋ถ„ ์šด์ „ ์กฐ๊ฑด์ด ์—ฐ์† ์šด์ „ ์กฐ๊ฑด์— ๋น„ํ•ด 30โˆผ100% ๊ฐ€๋Ÿ‰ ๋†’์€ ์—ด๊ตํ™˜ ํšจ์œจ์„ ์œ ๋ฐœํ•˜๋Š” ๊ฒƒ์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค.

(4)์ด์™€ ๊ฐ™์ด ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ ํ˜•ํƒœ๋ณ„ ์—ด๊ตํ™˜์œจ์€ ํฐ ์ฐจ์ด๋ฅผ ๋ณด์ด๋Š” ๊ฒƒ์„ ์•Œ ์ˆ˜ ์žˆ๋‹ค. ๋˜ํ•œ ์šด์ „ ์กฐ๊ฑด์— ๋Œ€ํ•ด์„œ๋„ ์ง€๋ฐ˜์œผ๋กœ ์ถ•์ ๋˜๋Š” ์—ด๋Ÿ‰์œผ๋กœ ์ธํ•ด ์—ด๊ตํ™˜์œจ์€ 30โˆผ100% ์ •๋„ ์ฐจ์ด๊ฐ€ ๋‚˜๋Š” ๊ฒƒ์„ ์•Œ ์ˆ˜ ์žˆ๋‹ค. ์‹ค์ œ ์ง€์—ด์‹œ์Šคํ…œ ๊ฐ€๋™์‹œ ์—ฐ์† ์šด์ „๋ณด๋‹ค๋Š” ์ฃผ๊ธฐ์ ์œผ๋กœ ์šด์ „์„ ํ•˜๋Š” ๊ฒƒ์ด ํฐ ํšจ๊ณผ๋ฅผ ๋ณผ ์ˆ˜ ์žˆ์„ ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋˜๋ฉฐ ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ ํ˜•ํƒœ๋ณ„ ์—ดํšจ์œจ๋งŒ ๋ถ„์„ํ•˜์˜€๊ธฐ์— ํ–ฅํ›„์—๋Š” ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ ํ˜•ํƒœ๋ณ„ ์‹œ๊ณต๋น„๋ฅผ ์‚ฐ์ •ํ•˜์—ฌ ๊ฒฝ์ œ์„ฑ์„ ๊ณ ๋ คํ•œ ์ง€์ค‘ ์—ด๊ตํ™˜๊ธฐ ์„ฑ๋Šฅ ๋ถ„์„์ด ํ•„์š”ํ•  ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

Acknowledgements

๋ณธ ์—ฐ๊ตฌ๋Š” ๊ตญํ† ๊ตํ†ต๋ถ€ ๊ตญํ† ๊ตํ†ต๊ณผํ•™๊ธฐ์ˆ ์ง„ํฅ์› ๊ฑด์„ค๊ธฐ์ˆ ํ˜์‹ ์‚ฐ์—…(11๊ธฐ์ˆ ํ˜์‹ E04)๊ณผ ๋ฏธ๋ž˜์ฐฝ์กฐ๊ณผํ•™๋ถ€ ํ•œ๊ตญ์—ฐ๊ตฌ์žฌ๋‹จ์˜ ๊ธฐ์ดˆ๊ณผํ•™์—ฐ๊ตฌ์‚ฌ์—…(2012-0005074)์˜ ์ง€์›์‚ฌ์—…์œผ๋กœ ์ˆ˜ํ–‰๋˜์—ˆ์œผ๋ฉฐ, ์ด์— ๊นŠ์€ ๊ฐ์‚ฌ๋ฅผ ๋“œ๋ฆฝ๋‹ˆ๋‹ค.

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Yoon, S., Lee, S. R., Park, H. and Park. S. (2012). โ€œThermal conductivity estimation of soils using coil shaped ground heat exchanger.โ€ Journal of Korean Society of Civil Engineers, Vol. 32, No. 5C, pp. 177-183 (in Korean).10.12652/Ksce.2012.32.5C.177Yoon, S., Lee, S. R., Park, H. and Park. S. (2012). โ€œThermal conductivity estimation of soils using coil shaped ground heat exchanger.โ€ Journal of Korean Society of Civil Engineers, Vol. 32, No. 5C, pp. 177-183 (in Korean).DOI