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세아 왕
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1 Korean Chem. Eng. Res., Vol. 44, No. 3, June, 2006, pp 지능형헬스케어욕조시스템개발을위한온수온도변화 r ~r l o l l e l r rte v v (2006 3o 9p r, o 20p }ˆ) Change of the Warm Water emperature for the Development of Smart Healthecare Bathing System Gi-Beum Kim Division of Bionics and Bioinformatics, he Research Center of Industrial echnology, he Research Center of Silver Engineering, Engineering Research Institute, College of Engineering, Chonbuk National University, , Duckjin-dong 1ga, Duckjin-gu, Jeonju, Jeonbuk , Korea (Received 9 March 2006; accepted 20 June 2006) k l l r l e v l p l ep ˆp nsp qo l pl m p l ep q. l nsp p p ep lr ep ep mp p ep n e rp r rpl. ns m p p v l p l ep v rpl., m p m m p m l m p v kp nep d l m p p p l. nsp m 41~45 C ov nep d 95Í ov p q rp Ž. h Abstract In this study, heat loss through free surface of water contained in bathtub due to conduction and evaporation has been analyzed. As a result of this study, a relational equation has been derived based on the basic theory of heat transfer to evaluate the performance of bath tubes. he derived equation was rational and quantitative. he major heat loss was found to be due to evaporation. Moreover, it has been found out that the speed of heat loss depends more on the humidity of the bathroom than the temperature of water contained in the bathtub. So, it is best to maintain the temperature of bathtub water to be between 41 to 45 C and the humidity of bathroom to be 95Í. Key words: Bathing System, Heat ransfer, Evaporation Heat Loss, Conductivity Heat Loss, Evaporation Latent Heat 1. nep n se l e, krp v rp p p m p l p., p nep p k l r v k l pv k p p v v }k p ~ p r p m [1]. t l lr p rp n p~l m p r rp p ˆp r lr s p o re o k ml v p l m., p -ml p o l t l p ml, p~p ml ƒ v sq l p lr p tep o whom correspondence should be addressed. kgb70@chonbuk.ac.kr l v l m [2, 3]. ne p r p ne nsl e rp l v l rp ns l p~ rp k l p [4]. p rp nsp lr l ns m p v l el ~w m p qo p v l e, w ns p lr e w v kp ns l p l e lv. p l l p l e pp, m p m l k p e lv. p v l e t w ~ w m wl 2Í p l p rp e p. d kt v kp l ~wp v l ep q v rp [5]. l l r m v l p l ep ˆp nsp qo l pl m p l ep q m. 270

2 2. m n 2-1. n i i m m p ()p p mq emp r mp, qo l p v l e pm p kp l ep ns rp qo rp ˆ p [5]. m p v p M, lp C P, r rp A, e t kl m 0 l, l v (1)e p ˆ p. t MC p ( 0 ) Ak = d 0 l, Ë ne p m p. p ep e r (2)e p ns m p ep p. = + ( 0 )e (2)e p ns m ep m p m e l pp v p k p., (2)ep k p 0 m ( ) e p e pp (3)ep lp p = 1 e 0 0 Ak t MC p p ep m p ep { in, k ns p r l el p l ns p m n p hl p p, PVC Ž mq l p v rp, e m n p h'l p p em v, p r p e p l Ë p lr l p lv [6]. l, h p. t Ak t MC p = = = = h k 1 1 k 2 2 h k k = k 1 k 2 h 1 v d l nsedš p o m m 271 (1) (2) (3) (4) p lr (k) 2-3. r i ns p m p p qo l p v l p vr p l ep tp v p. pm p po v ql p p pm p v l ep v rp npp [5] v v p p mr p ep lp p e p. Leem Suhp l p p m m m p p p n v l p E ev p (5)e p p ep l [5]. l, v p p, P s 5'p l p m l v kp P w p o l p erv kp v ql, L v qlp m p m r m e (6)e p ˆ p [5]. L = ( )S fg l, S fg v l p v l }p p [7] v l e v p qo p p tl kp qo r v p k pp, m v qlp v l e (Q ev )p l p r p lp pl (7)e p ˆ p. Q ev t = E ev ρldt = E ev ρl MC p d (7) 0 0 ( )ka l, dt = MC p e pp E ev v l p ( 0 )ka d p l pp e k qo r kl m p v l ep q r p k, r r m m d p p l kv p r p p l. r qo r A' f k. o e p v l e p E ev ρl(cal)p, qo l p r r A'p f l o l p ka' f ( Ë )/p. l A 'p f p (8)e p ˆ p. ρe ev L = k( ) 3. y 3-1. { in l km o lr p p rp n. l l p p e p lr p k r m. p Fig. 2m p l p 10 cm l nsqo l pl v p l ep. lp ns p r l e p p. e p p 0 (6) (8) E ev = ( v) P s P w ( ) 0.88 (5) Fig. 1. he composition of heat resistances materials. Korean Chem. Eng. Res., Vol. 44, No. 3, June, 2006

272 Fig. 2. Diagram to measure heat conductivity. sp qo p ll m p m e l r p. p kqp v l p l el p p p. p e l sp m p p 200 Lp. nsp 11 cmpl.

3 10 4 cal/cm oc secp lr lp p l. p p er ns p lr pp p. 3-2. r mi v qlp (6)ep pn l p. (6)el S fg v l p v l }p p. v l m l p m l ep o l Fig. 3 p ˆ pp S fg =3.486 0.

4m p ˆ p. l k p p m v v q lp p p p. qlp vp m k p pv k p ov l p rp lp p. pm p m v v qlp po ns m l 5' op m n sp m m m p l p. ne m ns m mp p tltp f v l p l ep e ˆ pp Ž.

3 272 Fig. 2. Diagram to measure heat conductivity. sp qo p ll m p m e l r p. p kqp v l p l el p p p. p e l sp m p p 200 Lp. nsp 11 cmpl. m p m 45 Cp nep m 21 C, d 80Ípl. e l p n mp 1e m p m 0.2 Cp m rmp, p n v kkp 1.3 Cp m ˆ l., 1e kl ns p l e 0.2 C p. (3)el lr r o l p p l cal/cm oc secp lr lp p l. p p er ns p lr pp p r mi v qlp (6)ep pn l p. (6)el S fg v l p v l }p p. v l m l p m l ep o l Fig. 3 p ˆ pp S fg = m p ep lp pl. p ep (6)el p l r (9)e p ˆ p. Fig. 4. Evaporation latent heat in terms of temperature. L = ( ) ( ) (9)ep pn l m l v qlp Fig. 4m p ˆ p. l k p p m v v q lp p p p. qlp vp m k p pv k p ov l p rp lp p. pm p m v v qlp po ns m l 5' op m n sp m m m p l p. ne m ns m mp p tltp f v l p l ep e ˆ pp Ž. (9) 3-3. r m m p v p o l (5)el m p l P s v pn l (10)e p ˆ pl. P s = e (10) Fig. 3. Evaporation entropy variation with temperature. o44 o k l, m ( C)p., (10)ep (5)el p l r v p p. (5)el P s m P w pl

v d l nsedš p o m m 273 Fig. 5. Amount of evaporation vs. bathroom temperature at several bathroom humidity. Fig. 6. he variation of m according to the bathroom humidity.

4 v d l nsedš p o m m 273 Fig. 5. Amount of evaporation vs. bathroom temperature at several bathroom humidity. Fig. 6. he variation of m according to the bathroom humidity. d P w =P s m p pp (P s P w ) 0.88 (P s P w ) 0.88 = P 0.88 s (1 ) ˆ 0.88 p. (10)ep ns m 35~50 Cp q o ep. p ep (5)el p l r (11)e p ˆ p. p ep nsp m p l v p ep ( ) ( ) 0.88 E ev = ( v) e (11) (11)el 1 p v ne p o p. nel p o p p n q l. l l p p o p e m. m l v p Fig. 5l ˆ l. l k p p ns d p n v m p kp kvp p pl., m p m p v m p kp v p p pl ml n ρe er qo r p ev L k qo r A' f ( ) p. p rp p p pp ρe ev L k( ) v k p p rp. qo rp o l m p able 1l e m. p p e l p l llv l k p p m p 41~45 C l m l v k prep p ep ˆ o l Fig. 6 p p. pm p l l rep pn l m = (1 ) p ˆ pp 0.2Í p m o ˆ p., e l n nsp qo r A' f =m e r p r p ep p p ns p p j m ns m p m o l (2)ep pn. (2)el n p w l v l p r r(a) o l qo r er m rp lk. v ka/mc p B r mp B p m p k r rp ˆ p. k r rp ne d p ˆ pp B p m p k ne d p ˆ p. l l Bp p m p k ne d p l able 2l ˆ l., able 2 pn l ne p d l l B p m o l Fig. 7 p ˆ l. l Bp p nep d l ˆ po ka/mc p l A A' f +A 0 p, qo rp d p p l l Bp p d p ˆ l. l A 0 er m r, A' f qo rp er qo rp. Fig. 7l llv ep pn l m p m m nep m l ns m p m ˆ p Fig. 8p. p l k p p 3e ne p d p able 1. Change amount of m by change of warm water temperature in various bathroom humidity ρe ev L/k( ) m =45 C =43 C =41 C Average Value m able 2. Change amount of B by change of warm water amount in various bathroom humidity B 50 L 100 L 150 L 200 L 250 L 300 L Korean Chem. Eng. Res., Vol. 44, No. 3, June, 2006

5 274 Fig. 7. Values of B vs. bathroom humidity according to the amount warm water. n d p m r ˆ., m p qp n n m r ˆ. m p m p m n m p m p ll r i m ns m p qo p o e v l e p E ev ρl(cal) e pp p l e p m p m l Fig. 9m p ˆ p. l k p p ns m p m p n v l p l ep., m p v v l p l e v p p p. po m p v rp v l p l ep pl qo rp v l v l ep v. v p ne d v v l p l ep kv p p ppp k pl n i m r l p l ep o qo l p r r 'p l o l p k ' ( Ë)/p pp Fig. 10 p ˆ p. r l p l ep v l p l e p p p p. l tn p r l p l e p v l p l e qp ep p p. ns m p m r l p l e m p q o p lv v l ep v rpp p pl. 4. l nsp p p ep lr ep ep mp p ep n e rp r rpm. ns m p p v l p l ep v rpl., m p m m p m l m p v kp nep d l m p p p l. nsp m 41~45 C ov nep d 95Í ov p q rp Ž. Fig. 8. Water temperature vs. time at various bathroom humidity. o44 o k

6 v d l nsedš p o m m 275 Fig. 9. Change of evaporation heat loss by change of warm water temperature in various bathroom humidity. Fig. 10. Change of conductivity heat loss by change of warm water temperature in various bathroom humidity. Korean Chem. Eng. Res., Vol. 44, No. 3, June, 2006

7 276 k M : mass of Hot Water [g] C p : specific heat [cal/g C] A : total conductivity area [cm 2 ] t : time [sec] 0 : intial temperature [ C] : temperature after t hours [ C] Ë : temperature in Bathroom [ C] : thickness of heat insulating material [cm] k : total thermal conductivity [cal/cm sec C] h v : film coefficient of heat transfer [cal/cm 2 sec C] : velocity of wind [cm/sec] P s : saturated vapor pressure of 5 point on surface of water [mmhg] P w : vapor pressure of 5 point on surface of water [mmhg] L : evaporation latent heat [cal] S fg : evaporation Entropy [cal/g] Q ev : evaporation Heat loss [kcal] A' f : equivalence free surface area [cm 2 ] : practical free surface area [cm 2 ] ρ : density [g/cm 3 ] : evaporation amount [g] E ev y 1. Kim, Y. C., Yu, M., Kim, H. J., Kwon,. K., Hong, C. U. and Kim, N. G., Analysis of hermal Environmental System in the Bathroom, 2005 Spring Joint Confcrence of ESK & KOSES, and he 8th Korea Japan Joint Symposium on Ergonomics, (2005). 2. Myong, H. K., Evaluation Index of Indoor hermal Environment, J. of the S.A.R.E.K., 21(4), (1992). 3. Kwon, O., Ko, J. W. and Lee, J. Y., Man-hermal Environment System, Kyung Choon Sa, Seoul, 13-15(2004). 4. Kim, Y. D., Hwang, K. M. and Kang, B. L., Exploratory Study on the Dimensions of Satisfaction with the Bathtub in the Apartment House, Journal of Marketing Research, 9(3), (2004). 5. Lee, B. H. and Suh, J. I., A Performance Equation of Bath ubes, J. of the S.A.R.E.K., 10(1), 1-11(1981). 6. Choi, I. G., Cho, S. H. and Ro, S.., Heat ransfer, Bosung, Seoul(1993). o44 o k

국706.fm

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