359 research outputs found

    ์ „๊ธฐ์ž๋™์ฐจ ๋‹ค์ค‘ ๋ ˆ๋ฒจ ์—ด๊ด€๋ฆฌ ์‹œ์Šคํ…œ๊ณผ ์šด์˜ ์ „๋žต์— ๊ด€ํ•œ ์—ฐ๊ตฌ

    Get PDF
    ํ•™์œ„๋…ผ๋ฌธ(๋ฐ•์‚ฌ) -- ์„œ์šธ๋Œ€ํ•™๊ต๋Œ€ํ•™์› : ๊ณต๊ณผ๋Œ€ํ•™ ๊ธฐ๊ณ„๊ณตํ•™๋ถ€, 2023. 2. ๊น€๋ฏผ์ˆ˜.๊ตญ์ œ์ ์œผ๋กœ ๋งŽ์€ ๊ตญ๊ฐ€์—์„œ ์ฐจ๋Ÿ‰์˜ ์ด์‚ฐํ™”ํƒ„์†Œ ๋ฐœ์ƒ๋Ÿ‰์ด๋‚˜ ์—ฐ๋น„๋ฅผ ๊ทœ์ œํ•จ์— ๋”ฐ๋ผ, ์ „๊ธฐ์ž๋™์ฐจ๊ฐ€ ์ฐจ์„ธ๋Œ€ ์นœํ™˜๊ฒฝ ์ฐจ๋Ÿ‰์œผ๋กœ ๋งŽ์€ ์ฃผ๋ชฉ์„ ๋ฐ›๊ณ  ์žˆ๋‹ค. ํ•˜์ง€๋งŒ ์ „๊ธฐ์ฐจ๋Š” ๊ฒจ์šธ์ฒ  ์ฃผํ–‰ ์‹œ ์ฐจ๋Ÿ‰ ์‹ค๋‚ด์˜ ๋‚œ๋ฐฉ์„ ์œ„ํ•œ ์ถ”๊ฐ€์ ์ธ ์—๋„ˆ์ง€ ์†Œ๋ชจ์™€ ๋ฆฌํŠฌ ์ด์˜จ ๋ฐฐํ„ฐ๋ฆฌ์˜ ๋‚ฎ์€ ์„ฑ๋Šฅ์œผ๋กœ ์ธํ•˜์—ฌ ์ฃผํ–‰๊ฑฐ๋ฆฌ๊ฐ€ ๊ฐ์†Œํ•˜๋Š” ๋ฌธ์ œ๊ฐ€ ๋ฐœ์ƒํ•œ๋‹ค. ์ด์— ๋”ฐ๋ผ, ํžˆํŠธํŽŒํ”„๊ฐ€ ๊ธฐ์กด ์ „๊ธฐ ํžˆํ„ฐ๋ฅผ ๋Œ€์‹ ํ•˜๋Š” ํšจ์œจ์ ์ธ ๋‚œ๋ฐฉ ๊ธฐ๊ตฌ๋กœ ํญ๋„“๊ฒŒ ์ ์šฉ๋˜๊ณ  ์žˆ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ ํžˆํŠธํŽŒํ”„ ์—ญ์‹œ ๊ทน์ €์˜จ ๊ตฌ๊ฐ„์—์„œ ์„ฑ๋Šฅ์ด ํฌ๊ฒŒ ๊ฐ์†Œํ•˜๋Š” ๊ฒฝํ–ฅ์ด ์žˆ๊ธฐ์—, ์ „์žฅํ’ˆ์œผ๋กœ๋ถ€ํ„ฐ ๋ฐœ์ƒํ•˜๋Š” ๋ฏธํ™œ์šฉ์—ด์„ ํšŒ์ˆ˜ํ•˜์—ฌ ๋ถ€์กฑํ•œ ์‹ค๋‚ด ๋‚œ๋ฐฉ๋ถ€ํ•˜๋ฅผ ๋ณด์ถฉํ•  ํ•„์š”๊ฐ€ ์žˆ๋‹ค. ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ๋ฏธํ™œ์šฉ์—ด์„ ํก์ˆ˜ํ•˜๋Š” ์˜จ๋„ ๋ ˆ๋ฒจ์„ ์„ธ๋ถ„ํ™”ํ•˜์—ฌ ํ™œ์šฉํ•˜๋Š” ๋‹ค์ค‘ ๋ ˆ๋ฒจ ์—ด๊ด€๋ฆฌ ์‹œ์Šคํ…œ์„ ์ œ์‹œํ•˜์˜€๋‹ค. ์ฒซ์งธ๋กœ, ์˜จ๋„ ๋ ˆ๋ฒจ์ด ํžˆํŠธํŽŒํ”„์— ๋ฏธ์น˜๋Š” ์˜ํ–ฅ์„ ๋ถ„์„ํ•˜์˜€๋‹ค. ๊ธฐ์ƒ ๋ƒ‰๋งค ์ค‘๊ฐ„์ฃผ์ž… ๊ธฐ์ˆ ์„ ํ™œ์šฉํ•  ๊ฒฝ์šฐ ๋ฏธํ™œ์šฉ์—ด์„ ์ค‘๊ฐ„ ์˜จ๋„ ๋ ˆ๋ฒจ์—์„œ ํšŒ์ˆ˜ํ•  ์ˆ˜ ์žˆ๋‹ค. ๋ƒ‰๋งค๊ฐ€ ์ค‘๊ฐ„ ์˜จ๋„ ๋Œ€์—ญ์—์„œ ๋ฏธํ™œ์šฉ์—ด์„ ํก์ˆ˜ํ•จ์— ๋”ฐ๋ผ ๋” ํฐ ๋‚œ๋ฐฉ์šฉ๋Ÿ‰์„ ํ™•๋ณดํ•  ์ˆ˜ ์žˆ๋‹ค. ๋ฏธํ™œ์šฉ์—ด์ด ์—†๋Š” ๋ฐฉ์‹, ๋ฏธํ™œ์šฉ์—ด์„ ์ €์˜จ์—์„œ ํšŒ์ˆ˜ํ•˜๋Š” ๋ฐฉ์‹, ๋ฏธํ™œ์šฉ์—ด์„ ์ค‘๊ฐ„ ์˜จ๋„ ๋ ˆ๋ฒจ์—์„œ ํšŒ์ˆ˜ํ•˜๋Š” ๋ฐฉ์‹์— ๋Œ€ํ•ด ์‹คํ—˜์—ฐ๊ตฌ๊ฐ€ ์ง„ํ–‰๋˜์—ˆ๋‹ค. ๊ฐ ๋ฐฉ์‹์€ ์™ธ๊ธฐ ์˜จ๋„, ์••์ถ•๊ธฐ ์†๋„, ๋ฏธํ™œ์šฉ์—ด์˜ ์–‘์„ ํฌํ•จํ•œ ๋‹ค์–‘ํ•œ ์กฐ๊ฑด์—์„œ ํ‰๊ฐ€๋˜์—ˆ๋‹ค. ์‹คํ—˜ ๊ฒฐ๊ณผ, ์ค‘๊ฐ„์˜จ๋„ ๋ ˆ๋ฒจ์—์„œ ๋ฏธํ™œ์šฉ์—ด์„ ํšŒ์ˆ˜ํ•˜๋Š” ๋ฐฉ์‹์ด ์ €์˜จ์—์„œ ํšŒ์ˆ˜ํ•˜๋Š” ๋ฐฉ์‹๋ณด๋‹ค 72% ๋†’์€ ๋‚œ๋ฐฉ์šฉ๋Ÿ‰์„ ํ™•๋ณดํ•  ์ˆ˜ ์žˆ๋Š” ๊ฒƒ์„ ํ™•์ธํ•˜์˜€๋‹ค. ๋งˆ์ฐฌ๊ฐ€์ง€๋กœ, ๋ฏธํ™œ์šฉ์—ด์„ ๊ณ ์˜จ์—์„œ ํšŒ์ˆ˜ํ•˜๋Š” ๋ฐฉ์‹ ์—ญ์‹œ ํ‰๊ฐ€๋˜์—ˆ๋‹ค. ํ”Œ๋กœํŒ… ๋ฃจํ”„๋Š” ๋ชจํ„ฐ์™€ ์ „๋ ฅ๊ธฐ๊ธฐ์˜ ์—ด๊ด€๋ฆฌ์— ์‘์ถ•๊ธฐ ํ›„๋‹จ์˜ ์•ก์ƒ ๋ƒ‰๋งค๋ฅผ ํ™œ์šฉํ•œ๋‹ค. ์ด๋ฅผ ํ†ตํ•ด ๊ฒจ์šธ์ฒ  ๋ฏธํ™œ์šฉ์—ด ํšŒ์ˆ˜์™€ ์—ฌ๋ฆ„์ฒ  ์—ด๊ด€๋ฆฌ๋ฅผ ์šฉ์ดํ•˜๊ฒŒ ํ•  ์ˆ˜ ์žˆ์œผ๋ฉฐ ์ด๋Š” 2์ƒ ๋ƒ‰๋งค์˜ ์šฐ์ˆ˜ํ•œ ์—ด์ „๋‹ฌ ํŠน์„ฑ ๋•Œ๋ฌธ์ด๋‹ค. ์ œ์•ˆ๋œ ์‹œ์Šคํ…œ์˜ ์„ฑ๋Šฅ์„ ์ž…์ฆํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ํžˆํŠธํŽŒํ”„์™€ ์ „์žฅํ’ˆ ํ•ด์„ ๋ชจ๋ธ์„ ๊ฐœ๋ฐœํ•˜๊ณ  ํ†ตํ•ฉํ•˜์˜€๋‹ค. ํ•ด์„ ๊ฒฐ๊ณผ, ํ”Œ๋กœํŒ… ๋ฃจํ”„๋ฅผ ํ™œ์šฉํ•œ ์‹œ์Šคํ…œ์˜ ์ „๋ ฅ ์†Œ๋ชจ๊ฐ€ ๊ฒจ์šธ์ฒ ์—๋Š” 27.7% ์—ฌ๋ฆ„์ฒ ์—๋Š” 5.8% ๊ฐ์†Œํ•œ ๊ฒƒ์„ ํ™•์ธํ•˜์˜€๋‹ค. ๋‘˜์งธ๋กœ, ๋‹ค์ค‘ ๋ ˆ๋ฒจ ์—ด๊ด€๋ฆฌ ์‹œ์Šคํ…œ์„ ๋ƒ‰์‹œ๋™ ์กฐ๊ฑด์—์„œ ํ‰๊ฐ€ํ•˜์˜€๋‹ค. ์•ž์„  ์—ฐ๊ตฌ๊ฒฐ๊ณผ์—์„œ ์•Œ ์ˆ˜ ์žˆ๋“ฏ์ด, ์—ด ํšŒ์ˆ˜ ์˜จ๋„๋Š” ์„ฑ๋Šฅ์— ํฐ ์˜ํ–ฅ์„ ๋ฏธ์นœ๋‹ค. ํ•˜์ง€๋งŒ ์ผ๋ฐ˜์ ์ธ ๋ฏธํ™œ์šฉ์—ด ํšŒ์ˆ˜๋Š” ํ•œ ์˜จ๋„ ๋ ˆ๋ฒจ๋งŒ์„ ํ™œ์šฉํ•˜๊ณ  ์ด๋Š” ์šดํ–‰ ์กฐ๊ฑด์— ๋”ฐ๋ผ ๋‹ฌ๋ผ์ง€๋Š” ์ตœ์  ์˜จ๋„ ๋ ˆ๋ฒจ์„ ํ™œ์šฉํ•  ์ˆ˜ ์—†๋‹ค. ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ์—ด ํšŒ์ˆ˜ ๋ ˆ๋ฒจ์„ ์ €์˜จ, ์ค‘์˜จ, ๊ณ ์˜จ์˜ ์„ธ ์˜จ๋„ ๋ ˆ๋ฒจ๋กœ ์„ธ๋ถ„ํ™”ํ•˜๊ณ  ๊ฐ ์˜จ๋„์—์„œ์˜ ์—ด ํšŒ์ˆ˜ ์„ฑ๋Šฅ์„ ํ‰๊ฐ€ํ•˜์˜€๋‹ค. ํžˆํŠธํŽŒํ”„์˜ ๋™์  ๊ฑฐ๋™์„ ๋ฐ˜์˜ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ์‹คํ—˜์ด ์ง„ํ–‰๋˜์—ˆ๊ณ , ์ด๋ฅผ ๋ฐ”ํƒ•์œผ๋กœ ํžˆํŠธํŽŒํ”„ ๋™์  ๋ชจ๋ธ์„ ์ˆ˜๋ฆฝํ•˜์˜€๋‹ค. ์ „์žฅํ’ˆ ๋™์  ๋ชจ๋ธ๊ณผ ํžˆํŠธํŽŒํ”„ ๋™์  ๋ชจ๋ธ์„ ํ†ตํ•ฉํ•˜์—ฌ ํ†ตํ•ฉ ์—ด๊ด€๋ฆฌ ๋ชจ๋ธ์„ ๊ตฌ์„ฑํ•˜์˜€๋‹ค. ํ•ด๋‹น ๋ชจ๋ธ์„ ํ™œ์šฉํ•˜์—ฌ ๋‹ค์–‘ํ•œ ๋ƒ‰์‹œ๋™ ์กฐ๊ฑด์—์„œ ๋ฏธํ™œ์šฉ์—ด ํšŒ์ˆ˜ ์ „๋žต์„ ํ‰๊ฐ€ํ•˜์˜€๋‹ค. ํ‰๊ฐ€ ๊ฒฐ๊ณผ, ์ตœ์ ์˜ ๋ฏธํ™œ์šฉ์—ด ํšŒ์ˆ˜ ์˜จ๋„๋ฅผ ํ™œ์šฉํ•  ๊ฒฝ์šฐ ์ผ๋ฐ˜์ ์ธ ์—ด ํšŒ์ˆ˜ ์ „๋žต์— ๋น„ํ•ด 13%์˜ ์†Œ๋ชจ๋™๋ ฅ ์ ˆ๊ฐ ํšจ๊ณผ๋ฅผ ๋‚˜ํƒ€๋‚ด๋Š” ๊ฒƒ์„ ํ™•์ธํ•˜์˜€๋‹ค. ์„ธ๋ฒˆ์งธ๋กœ, ๋‹ค์ค‘ ๋ ˆ๋ฒจ ๋ฏธํ™œ์šฉ์—ด ํšŒ์ˆ˜ ์ „๋žต์˜ ๊ฒฝ์šฐ ๊ธฐ์ƒ ๋ƒ‰๋งค ์ฃผ์ž… ๊ธฐ์ˆ ์„ ํ™œ์šฉํ•˜๊ธฐ์—, ์ฃผ์ž… ํฌํŠธ์˜ ๋””์ž์ธ์ด ์„ฑ๋Šฅ์— ํฌ๊ฒŒ ์˜ํ–ฅ์„ ๋ฏธ์นœ๋‹ค. ํ•˜์ง€๋งŒ ํ˜„์žฌ์˜ ํฌํŠธ ๋””์ž์ธ์€ ๊ธฐ์•ก๋ถ„๋ฆฌ๊ธฐ๋‚˜ ๋‚ด๋ถ€ ์—ด๊ตํ™˜๊ธฐ๋ฅผ ํ™œ์šฉํ•œ ์ฃผ์ž… ์‹œ์Šคํ…œ์— ์ตœ์ ํ™”๋˜์–ด ์„ค๊ณ„๋˜์—ˆ๋‹ค. ๊ธฐ์ƒ ๋ƒ‰๋งค ์ฃผ์ž… ๊ณผ์ •์„ ์ •ํ™•ํ•˜๊ฒŒ ๋ชจ์‚ฌํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ์ƒˆ๋กœ์šด ์ฃผ์ž… ๋ชจ๋ธ์ด ๊ฐœ๋ฐœ๋˜์—ˆ๋‹ค. ์œ„ ๋ชจ๋ธ์€ ์••์ถ• ์ฑ”๋ฒ„ ๋‚ด์˜ ์••๋ ฅ ์ฆ๊ฐ€์™€ ์ œํŠธ ์ถฉ๋Œ ๊ฑฐ๋™์„ ๋ฐ˜์˜ํ•˜์˜€๋‹ค. ๋ณธ ์ฃผ์ž… ๋ชจ๋ธ์„ ํฌํ•จํ•œ ์Šคํฌ๋กค ์••์ถ•๊ธฐ ๋ชจ๋ธ์„ ๋ฐ”ํƒ•์œผ๋กœ ํžˆํŠธํŽŒํ”„ ์‹œ์Šคํ…œ์ด ๋ถ„์„๋˜์—ˆ๊ณ , ํฌํŠธ์˜ ํฌ๊ธฐ์™€ ์œ„์น˜์— ๋”ฐ๋ฅธ ์‹œ์Šคํ…œ์˜ ์„ฑ๋Šฅ์„ ํ‰๊ฐ€ํ•˜์˜€๋‹ค. ํ‰๊ฐ€ ๊ฒฐ๊ณผ, ์ตœ์ ์˜ ํฌํŠธ๋Š” 2mm ๋ฐ˜๊ฒฝ์„ ๊ฐ€์ง„ ๋“€์–ผ ํฌํŠธ์ด๊ณ  ์œ„์น˜๋Š” 600ยฐ๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ๋งˆ์ง€๋ง‰์œผ๋กœ, ๋ฐฐํ„ฐ๋ฆฌ ์Šน์˜จ ์ „๋žต์ด ์ œ์‹œ๋˜์—ˆ๋‹ค. ์ „๊ธฐ์ž๋™์ฐจ์˜ ์—๋„ˆ์ง€ ์ €์žฅ ์‹œ์Šคํ…œ์ด ์ €์˜จ์—์„œ ์ž‘๋™ํ•  ๊ฒฝ์šฐ, ๋‚ด๋ถ€์ €ํ•ญ์˜ ์ฆ๊ฐ€๋กœ ์ถœ๋ ฅ๊ณผ ์šฉ๋Ÿ‰์ด ํฌ๊ฒŒ ๊ฐ์†Œํ•œ๋‹ค. ๋”ฐ๋ผ์„œ ์ด๋กœ ์ธํ•œ ์ฃผํ–‰๊ฑฐ๋ฆฌ ๊ฐ์†Œ๋ฅผ ๋ฐฉ์ง€ํ•˜๊ธฐ ์œ„ํ•ด์„œ๋Š” ์ ์ ˆํ•œ ์—ด๊ด€๋ฆฌ๊ฐ€ ํ•„์š”ํ•˜๋‹ค. ์ตœ์ ์˜ ๋ฐฐํ„ฐ๋ฆฌ ์—ด๊ด€๋ฆฌ ์ „๋žต์„ ๋„์ถœํ•˜๊ธฐ ์œ„ํ•ด์„œ๋Š” ๋ฐฐํ„ฐ๋ฆฌ ์Šน์˜จ์„ ํ†ตํ•œ ์„ฑ๋Šฅ ํ–ฅ์ƒ๊ณผ ์Šน์˜จ์„ ์œ„ํ•ด ์†Œ๋น„๋˜๋Š” ์—๋„ˆ์ง€๋ฅผ ์‹œ์Šคํ…œ ์ธก๋ฉด์—์„œ ๊ณ ๋ คํ•ด์•ผ ํ•œ๋‹ค. ํŒฉ ๋‹จ์œ„์˜ ๋ฐฐํ„ฐ๋ฆฌ ์—ด๋ชจ๋ธ๊ณผ ์…€ ๋‹จ์œ„์˜ ๋ฐฐํ„ฐ๋ฆฌ ์„ฑ๋Šฅ ๋ชจ๋ธ์„ ํ†ตํ•ฉํ•œ ๋ฐฐํ„ฐ๋ฆฌ ๋ชจ๋ธ์„ ๊ฐœ๋ฐœํ•˜์˜€๊ณ  ์ด๋ฅผ ํžˆํŠธํŽŒํ”„ ๋ชจ๋ธ๊ณผ ๊ฒฐํ•ฉํ•˜์˜€๋‹ค. ์œ„ ๋ชจ๋ธ์„ ํ†ตํ•ด ๋ฐฐํ„ฐ๋ฆฌ ์Šน์˜จ, ์ž๊ฐ€ ๋ฐœ์—ด, ๋ฐฐํ„ฐ๋ฆฌ ํก์—ด ์„ธ๊ฐ€์ง€ ์ „๋žต์„ ๋น„๊ตํ•˜์˜€๋‹ค. ๋น„๊ต ๊ฒฐ๊ณผ ์ €์˜จ ๊ตฌ๊ฐ„์—์„œ์˜ ๋ฐฐํ„ฐ๋ฆฌ ์Šน์˜จ์„ ํ†ตํ•ด ์ตœ๋Œ€ 18.8%์˜ ์ฃผํ–‰๊ฑฐ๋ฆฌ๋ฅผ ์ถ”๊ฐ€๋กœ ํ™•๋ณดํ•  ์ˆ˜ ์žˆ์—ˆ๊ณ , ํžˆํŠธํŽŒํ”„๋ฅผ ํ™œ์šฉํ•˜์—ฌ ๋ฐฐํ„ฐ๋ฆฌ ์˜ˆ์—ด์„ ํ•  ๊ฒฝ์šฐ ๋™์ผํ•œ ์˜ˆ์—ด ์„ฑ๋Šฅ์„ 38.4% ์ ์€ ์—๋„ˆ์ง€ ์†Œ๋ชจ๋กœ ๊ตฌํ˜„ํ•  ์ˆ˜ ์žˆ์—ˆ๋‹ค. ์ €์ž๋Š” ๋ณธ ์—ฐ๊ตฌ๋ฅผ ๋ฐ”ํƒ•์œผ๋กœ ๋‹ค์ค‘ ๋ ˆ๋ฒจ ์—ด๊ด€๋ฆฌ ์‹œ์Šคํ…œ์ด ๋ณด๊ธ‰๋˜์–ด ์ „๊ธฐ์ฐจ์˜ ์ฃผํ–‰๊ฑฐ๋ฆฌ ๋ฌธ์ œ์˜ ํ•ด๊ฒฐ์— ๊ธฐ์—ฌํ•˜๋Š” ๊ฒƒ์„ ๊ธฐ๋Œ€ํ•œ๋‹ค.As many global regulations restricts CO2 emission and fuel economy of automobiles, electric vehicles (EVs) have attracted great attention as a promising zero-emission vehicle. However, EVs suffer from the range loss at cold ambient temperature due to increased power consumption on cabin heating and low performance of lithium-ion battery. Therefore, heat pumps are widely adopted as an energy-efficient heating device replacing the positive temperature coefficient heater. However, the performance of heat pumps deteriorates at low ambient temperature so that the waste heat from electric devices is recovered to supplement the insufficient heating capacity in winter. In this study, I suggest a multi-level thermal management system (MLTMS), which utilizes the subdivided temperature levels recovering the waste heat. Firstly, the effect of temperature levels on the heat pump system was investigated. The vapor injection technique enables the recovery of waste heat at an intermediate temperature level. As the refrigerant absorbs waste heat at intermediate temperature level, larger heating capacity is provided to the cabin. Experiments were conducted in three modes: non-waste heat recovery, conventional waste heat recovery, and multi-level waste heat recovery. The performance of each mode was investigated under different operating conditions, including the ambient air temperature, compressor speed, and amount of waste heat. Results show that multi-level waste heat recovery augments heating capacity up to 72.5% in the coldest condition of -20 ยฐC while maintaining the temperature of the energy storage system within an appropriate operating range. Likewise, the waste heat recovery at high temperature level was evaluated. The floating loop manages the thermal state of power electronics and electric motors by utilizing the liquid refrigerant at the condenser outlet. This loop recovers the waste heat in winter and enhances the cooling performance in summer through the superior cooling performance of evaporative heat transfer. Configurations of heat pump and thermal management system are presented with operating schematic in summer and winter. To verify the performance of the suggested system, the heat pump and thermal management system model is established based on experimentally validated heat pump component models and electric device models. The result shows that the heat pump system utilizing a floating loop can save power consumptions in winter up to 27.7% and 5.8% in summer while maintaining the thermal state of electric devices within the appropriate range. Secondly, the performance of multi-level thermal management system was estimated from the cold-start condition. As aforementioned results demonstrate, the temperature level, at which the waste heat is recovered, affects the performance of the heat pump system. However, the conventional waste heat recovery strategy (WHRS) simply depends on one temperature level, even though the optimal temperature level changes depending on the operating conditions. The performance of the WHRSs, recovering heat at different temperature levels, was investigated. Temperature levels of WHRSs were divided into three: conventional (low), multi-level (intermediate), and direct (high). Experiments were conducted to examine the dynamic behavior of the heat pump system, and a transient model was established based on the experimental data. The electric device thermal model was consolidated into the integrated thermal management system model. The model evaluated heating performance and power consumption of WHRSs from various start-up conditions. Results show that the optimal WHRS saves the power consumption up to 13 % compared with conventional WHRS at the ambient temperature of -20ยฐC under Artemis highway driving profile. Thirdly, as the MWHR depends on the vapor injection technique, the port hole design critically affects the system performance. However, none of existing injection port is designed to be used with MWHR. The effect of port design on the MWHR system was investigated. A novel injection model was established, considering the continuously increasing pressure in the injected chamber and jet impingement behavior. The scroll compressor model with the injection process was integrated into a transient heat pump model. The effect of injection port location and size were investigated with the integrated thermal management system model under cold-start conditions. The optimal port hole design was suggested as the dual-port at 600 ยฐ with a radius of 2 mm from the perspective of total energy consumption. We anticipate that this study proposes a reference data and an optimization methodology in designing the port hole in the MWHR system. Lastly, an active battery thermal management strategy (BTMS), which uses the secondary loop in an electric vehicle heat pump, is suggested. When an energy storage system (ESS) operates in cold conditions, the power and capacity of the battery critically fade with high internal resistance. Therefore, appropriate BTMS is essential to prevent severe driving range loss at low ambient temperatures. To derive optimal BTMS, the trade-off between performance enhancement by ESS heating and additional energy consumption on the heating needs to be evaluated from the perspective of an integrated thermal management system (ITMS). We established a battery thermal model by combining a pack-level thermal model and a cell-level performance model. The battery thermal model was integrated with a transient heat pump model to estimate the performance of three BTMSs: self-heating, active heating, and heat recovery. Active heating of the battery augmented the driving range of EV up to 18.8%, whereas the heat recovery saved state-of-charge (SOC) decrease in non-depleted conditions. Furthermore, battery preheating with the heat pump achieved a temperature rise of 20 ยฐC within an hour, consuming 38.4 % less power of the battery, compared with electric heater preheating. I expect that this study provides an insight on MLTMS and promote broad adoption of MWHR as a solution to EV range reduction.Chapter 1. Introduction 1 1.1. Background of the study 1 1.2. Literature survey 8 1.2.1. Adoption of heat pumps in electric vehicle 8 1.2.2. Recent technologies to improve heating performance of EVHP 12 1.2.3. Integrated thermal management system (ITMS) 16 1.3. Objectives and scopes 19 Chapter 2. Effect of temperature level on the waste heat recovery performance 23 2.1. Introduction 23 2.2. Waste heat recovery at intermediate temperature level 27 2.2.1. Experimental setup 27 2.2.2. Accuracy of measuring devices and uncertainty analysis 35 2.2.3. Test procedure 38 2.2.4. Results and discussion 40 2.3. Waste heat recovery at high temperature level 57 2.3.1. System description 57 2.3.2. Model description 65 2.3.3. Results and discussion 83 2.4. Summary 96 Chapter 3. Multi-level waste heat recovery system 99 3.1. Introduction 99 3.2. Model description 101 3.2.1. Scroll compressor modeling 101 3.2.2. System modeling 113 3.2.3. Electric device modeling 123 3.3. Results and discussion 126 3.4. Summary 142 Chapter 4. Port design optimization of multi-level waste heat recovery system 144 4.1. Introduction 144 4.2. Results and discussion 146 4.3. Summary 161 Chapter 5. Active battery thermal management strategy 163 5.1. Introduction 163 5.2. Battery model descprtion 163 5.2.1. Battery performance experiment at low temperatures 164 5.2.2. Battery heating strategies 172 5.3. Results and discussion 175 5.4. Summary 186 Chapter 6. Concluding remarks 188 Reference 192 Abstract (in Korea) 219๋ฐ•

    Examples of Matrix Factorizations from SYZ

    Full text link
    We find matrix factorization corresponding to an anti-diagonal in CP1ร—CP1{\mathbb C}P^1 \times {\mathbb C}P^1, and circle fibers in weighted projective lines using the idea of Chan and Leung of Strominger-Yau-Zaslow transformations. For the tear drop orbifolds, we apply this idea to find matrix factorizations for two types of potential, the usual Hori-Vafa potential or the bulk deformed (orbi)-potential. We also show that the direct sum of anti-diagonal with its shift, is equivalent to the direct sum of central torus fibers with holonomy (1,โˆ’1)(1,-1) and (โˆ’1,1)(-1,1) in the Fukaya category of CP1ร—CP1{\mathbb C}P^1 \times {\mathbb C}P^1, which was predicted by Kapustin and Li from B-model calculations

    Pairings in mirror symmetry between a symplectic manifold and a Landau-Ginzburg BB-model

    Full text link
    We find a relation between Lagrangian Floer pairing of a symplectic manifold and Kapustin-Li pairing of the mirror Landau-Ginzburg model under localized mirror functor. They are conformally equivalent with an interesting conformal factor (volFloer/vol)2(vol^{Floer}/vol)^2, which can be described as a ratio of Lagrangian Floer volume class and classical volume class. For this purpose, we introduce BB-invariant of Lagrangian Floer cohomology with values in Jacobian ring of the mirror potential function. And we prove what we call a multi-crescent Cardy identity under certain conditions, which is a generalized form of Cardy identity. As an application, we discuss the case of general toric manifold, and the relation to the work of Fukaya-Oh-Ohta-Ono and their ZZ-invariant. Also, we compute the conformal factor (volFloer/vol)2(vol^{Floer}/vol)^2 for the elliptic curve quotient P3,3,31\mathbb{P}^1_{3,3,3}, which is expected to be related to the choice of a primitive form.Comment: 35 pages, 5 figures. Comments are welcom

    THE BEGINNING OF THE PATH TO SELF-DISCOVERY: A STUDY ON LIANG QICHAO'S CONCEPT OF NATION

    Get PDF
    In this thesis, I will analyze how Liang Qichaoโ€™s idea of nation played a role in the emergence of national identity in China in the late nineteenth and early twentieth century. The concept of nation in China didnโ€™t emerge from the bottom-up spontaneously. Rather, I will argue, the emergence of Chinese national identity can largely be explained as an imported ideology pursued by Chinese elites. In the formation of the concept of nation in China, not only the contact with the West but also interactions and tensions among the East Asian countries were crucial. This thesis is divided into two interdependent parts. The first part deals with theoretical studies of nationalism and national identity, and it will provide a general picture of the major theoretical trend in nationalism. This part will explore three major perspectives: the primordialist perspective that describes ethnic identities as something fixed and unchanging; the ethno-symbolist perspective that argues that pre-modern ethnic ties are important in understanding the formation of modern nations and nationalism; and the modernist perspective that treats nationalism as a recent phenomenon. Through a critical evaluation of theories of nationalism and national identity, I will begin to discern the contours of how Liang Qichaoโ€™s concept of nation was formed. In the second part, by way of introducing nationalist discourses in China, I will explore historical concepts of nation and its boundaries. Since his arrival in Japan, Liang immersed himself in Western political theory and read Japanese authors broadly, and his thoughts changed accordingly. As a result, Liang advocated great nationalism that would awaken a sense of belonging to China in all the peoples of the Qing Empire. In this regard, the introduction of Liangโ€™s borrowed concept of nation to China was a transformative event for Chinese national self-perception
    • โ€ฆ
    corecore