ExperimentalEvaluationofInfluenceofAirInjectionRateonaNovelSingleSlopeSolarStillIntegratedwithanAirCompressor

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1 Global Journal o Researches in Enineerin: Mechanical and Mechanics Enineerin Volume 17 Issue 3 Version 1.0 ype: Double Blind Peer Revieed International Research Journal Publisher: Global Journals Inc. (US) Online ISSN: Print ISSN: Experimental Evaluation o Inluence o ir Injection Rate on a Novel Sinle Slope Solar Still Interated ith an ir Compressor By Khaoula Hidouri & Dhananjay R. Mischra bstract- In this paper, experimental evaluation and mathematical modelin o sinle slope hybrid solar still interated ith an air compressor at a dierent air injection rate ithin ater basin. compressor unit is used to inject air ith dierent lo rate viz. 0.01, 0.03, 0.05 and 0.06 K/s in sea ater ithin the basin area o hybrid solar still. Compressed air injection in ater inluences the perormance parameters such as the temperatures and dierent modes o heat transer rate. Rate o convective heat transer beteen ater and air reaches 2.2 W / m² C, beteen air and lass the convective heat coeicient equal 0.6 W/ m² C. he temperature dierence beteen ater and inner lass surace, ith an addition o dry air inside the basin ill enhance cumulative productivity (Pcu) o the hybrid sinle slope solar still and recorded 16 L/m².day. Keyords: eect o air injection; hybrid solar still; heat transer coeicients. GJRE- Classiication: FOR Code: p Jaypee University o Enineerin and echnoloy, Enineers National o Gabes ExperimentalEvaluationoInluenceoirInjectionRateonaNovelSinleSlopeSolarStillInteratedithanirCompressor Strictly as per the compliance and reulations o: Khaoula Hidouri & Dhananjay R. Mishra. his is a research/revie paper, distributed under the terms o the Creative Commons ttribution-noncommercial 3.0 Unported License permittin all non commercial use, distribution, and reproduction inany medium, provided the oriinal ork is properly cited.

2 Experimental Evaluation o Inluence o ir Injection Rate on a Novel Sinle Slope Solar Still Interated ith an ir Compressor Khaoula Hidouri α & Dhananjay mischra σ bstract- In this paper, experimental evaluation and mathematical modelin o sinle slope hybrid solar still interated ith an air compressor at a dierent air injection rate ithin ater basin. compressor unit is used to inject air ith dierent lo rate viz. 0.01, 0.03, 0.05 and 0.06 K/s in sea ater ithin the basin area o hybrid solar still. Compressed air injection in ater inluences the perormance parameters such as the temperatures and dierent modes o heat transer rate. Rate o convective heat transer beteen ater and air reaches 2.2 W / m² C, beteen air and lass the convective heat coeicient equal 0.6 W/ m² C. he temperature dierence beteen ater and inner lass surace, ith an addition o dry air inside the basin ill enhance cumulative productivity (Pcu) o the hybrid sinle slope solar still and recorded 16 L/m².day. comparative study o convective, evaporative heat transer coeicients also has been reported. Keyords: eect o air injection; hybrid solar still; heat transer coeicients. I. Introduction he demand or potable clean ater is increasin day by day due to the roin population and industrialization across all over the orld. ir heatin is one o the most important applications o solar enery [1]. Pandey [2] has iven the bubblin eect o ambient air alon ith the simultaneous air bubblin and coolin o the lass cover, He has also compared an enhancement in distillate output hich as reported 33.5 and 47.5 percent respectively on conventional sinle slope solar still. l-sulaiman et al. [3] studied the perormance o to dierent coniurations o deployment o an air heater beore and beteen humidiier and dehumidiier (HDH) system. he study demonstrates that the HDH coniuration ith the air heater placed beteen the humidiier and the dehumidiier ill ive better perormance and hiher productivity as compared to the system hen air heater is placed beore the HDH. hey have also reported the case hen saline ater is directly heated by the incident solar radiation and air enters into the humidiier throuh the nozzles, mixes ith the ater, ats humidiied. Part o the air has condensed in the lass cover and the uthor α: Enineers National o Gabès, Omar Ibn El Khattab Street, Gabès 6029, unisia. uthor σ: Department o Mechanical Enineerin, Jaypee University o Enineerin and echnoloy.b. Road, Guna M.P. (India). dm30680@yahoo.com remainin air condensed in the dehumidiier system. he experiments have been carried out ith the eect o solar air heater ithout turbulator and ith the turbulator ater heater. he maximum speciic humidity ains ere recorded k ater /k air. Whereas the humidiier interated ith the solar air heater ithout turbulator has iven maximum speciic humidity ain o 0.11 k ater / k air. he peak distillate o k/m 2 day ere collected and reported [4]. Evacuated solar ater heater interated ith the desalination unit by Kabeel et al. [5]. ir has been circulated either by natural or orced circulation (he eect o three types o orced circulatin air: up, don and up-don) in conventional solar still. It has been reported that the orced don air circulation system ives a hiher perormance as compared to orced up, orced up-don and natural air circulation. ouz [6] has experimentally evaluated the eect o ater temperature, air lo rate and ater level on productivity in HDH desalination system. He has observed maximum productivity o the system hich reaches to 8.22 k/h at ater temperature 86 C and air mass ith a lo rate o 14 k/h. n experimental investiation o HDH desalination system has been used or ater and air heatin simultaneously durin the distillation process. he heated air and ater rom the collector supplied to the humidiier, here the air ets humidiied and moves toards dehumidiier or condensation. he system ability as investiated by varyin the lo rate o air, hot ater in the humidiier and coolin ater in a dehumidiier. he system distillation capacity enhances the air and ater temperature and lo rate o air, hot ater, and cold ater. he hihest productivity as recorded 12.36, and k/m 2.day or the ithout turbulators, convex and concave turbulators in absorber plate respectively [7]. Kabeel et al. [8] investiated an experimental study o a double passes solar air collector coupled modiied solar still, ith phase chane material (PCM). comparison beteen modiied still and PCM, orced hot air injection and conventional still as conducted to evaluate the development in the reshater productivity under the same atmospheric conditions. he experimental results have revealed that the daily reshater productivity o the modiied still hiher than that o conventional solar still. he reshater productivity reached 9.36 L/m 2. day 31 Global Journal o Researches in Enineerin ( ) Volume XVII Issue III Version I

3 ith an ir Compressor 32 Global Journal o Researches in Enineerin ( ) Volume XVII Issue III Version I or modiied solar still, hich as 108% hiher than that o the conventional solar still. Nada et al. [9] ere proposed a hybrid air-conditionin and HDH desalination system. he eect o resh air ratio, space supply air temperature, outside air et bulb temperature on the reshater productivity, rerieration capacity, compressor poer and percentae o poer savin are also presented. heir analysis shos that the locatin o an evaporative cooler ater the mixin o resh air ith return air remarkably increased the productivity o the distiller unit. Ghazy et al. [10] have undertaken an analytical study o a direct solar distillation system that combined solar still ith an air heatin humidiicationdehumidiication subsystem. Various procedures have been employed to improve the thermal perormance o d dt d dt the interated system by recoverin heat losses rom one component in another component o the system. his research ork depicts experimental evaluation results, viz. productivity, the behavior o heat transer coeicients or active solar still hybrid ith an air compressor or dierent lo rates o air ithin the hybrid sinle slope solar still interated ith the air compressor, to aument the production o drinkin ater. II. heoretical Backround Enery balance equations or evaluation o the heat and mass transer coeicients ithin the hybrid solar still can be ritten as: S = (α( 1 ϕ )G + (qe + qr, + qc, ) r, a c, a ) (1) (m C ) p d dt S = (( 1 α )( 1 ϕ )αg + q (m C ) p d dt Sb (m C S = (qc + qe, (m C ) e pe c,b + q c ) ev, (2) r, e c, b = b pb r, e, ) c, (( 1 α )( 1 ϕ )( 1 α )αbg c,b losses ) (4) ) dm dt MLB sotare is used or evaluation o dierent mode o heat and mass transer (conduction, convection, radiation, and evaporation), variation in temperature ithin the distiller unit and the distillate lo rate. In the orced convection mode, the relation beteen Nusselt (Nu), Reynolds (Re) and Prandtl number (Pr) as iven by [11] Nu = h c L = Re Pr 1/3 (6) k i Where, h c is the convective heat transer coeicient that can be evaluated as, he evaporative heat transer coeicient (h e ) can be ritten as [11]: he Lv M 1 = (7) h c M P c p he ratio o the heat transer coeicient and the mass transer coeicient is equal to the speciic heat per unit volume at a constant pressure o the mixture. Either the Leis relation [12]. he = 1 (8) h C m ρ p a q L e e = (5) v hereore, me h m ( ρ ρ ) (3) = (9) Substitutin Eqs. 7 and 8 in Eq.9 one can et. III. m hc. M e = ( P P ) (10) ρ C R. p Construction o Experimental Setup he test ri is made ith the help o stainless steel material o 3mm thick plate, hich has 0.4 m 2 o the basin area. Loer and hiher all o distiller units are kept 480 mm and 610 mm hih to make 30 o inclination o the lass cover, considerin latitude N and Lonitude E o city Gabès. ransparent 4 mm thick lass material is used as a cover or the basin area ith about 90% transmittance. Gasket rubber material is used in beteen basin top and lass cover and urther sealed ith indo putty to

4 prevent the leakae o vapors rom basin to ambient. he condensation ater is collected in a collector channel, hich is deposited at the loer end o the lass cover and small plastic pipe ill be used to terminate collector channel. Fresh ater is inally collected in an externally raded cylinder attached at the end dischare pipe. Feed ra/ saline ater pipe has been connected to another side all or eedin the brackish ater into a distiller unit. Fi. 1a shos that the air compressor is connected to a screen equipped ith holes or diusin air into the seaater basin o distiller unit. It has been added in order to increase the evaporation rate o ater containin in the basin by hybrid distiller unit. he air bloer connected to an air screen, urther it is connected to tap o a compressor. 33 Fiure 1a: Schematic arranement o SSDHP ith air pump Global Journal o Researches in Enineerin ( ) Volume XVII Issue III Version I ith an ir Compressor Dierent parameters viz., air lo rate, ater temperature, ater level and relative air humidity and temperature ithin the basin inlet and on the ater surace, ere recorded durin the experiments. he ater temperatures in the basin ere also measured usin the thermometer-pt100 hich orks in the rane rom 20 to +260ºC ith an uncertainty o 2.6%. he Fiure1b: ctual photoraph o SSDHP ith air pump relative humidity and temperature o air streams ere measured usin 2 thermo-hyrometers hich ork in the rane rom 0 to 100% RH and rom 40 to+120ºc and its uncertainty is 1.4% tabulated in able 1, able 2 shos operatin characteristics o dierent components.

5 ith an ir Compressor able 1: Details o measurin equipment and its rane alon ith their accuracy 34 Global Journal o Researches in Enineerin ( ) Volume XVII Issue III Version I IV. Measurin Equipments K-type thermocouple Diital dierential pressure manometer Diital thermo hyrometer hermometer- Pt100 Number Rane ccuracy 5-200to1250 C 2 (+-)2bar -0.2 C to+2 C -2% to +2% 2 0% to 100% RH -1.4% +1.4%RH 4 20 to +260C 2.6%. abel 2: Operatin characteristics Parameter Symbol Value Unit Mass o lass m k/m² Mass o ater m 20.6 k/m² Mass o basin m b 15.6 k/m² Caloriic heat capacity o lass C p 800 J/k C Caloriic heat capacity o ater C p 4178 J/k C Caloriic heat capacity o basin C pb 480 J/k C bsorbability o cover lass α Water absorbability α Basin absorbability α b Glass emissivity ε Water emissivity ε Basin emissivity ε b Glass relectivity ρ Water ρ Basin ρ b hermal conductivity o basin k b W/m K hermal conductivity o losses k i W/m K Experimental Procedure he experimental setup is desined and constructed to investiate the eect on the productivity o hybrid solar still at a dierent lo rate o air ithin the test ri throuh compressor unit. While the experimentation temperature o the lass cover, ater, and evaporator as recorded ith the help o K type thermocouple, hereas the lo rate o air as recorded ith the help o Rotameter and control ith the help o reulatory valve. Distillate output is recorded ith the help o raduated cylinder on an hourly basis. Each series o experiments ere conducted or our dierent air lo rates (0.01, 0.03, 0.05 and 0.06 k/s) at a constant ater level o 10 cm. Incident solar radiation is recorded ith the help o pyranometer. V. Economic nalysis Usin economic analysis, estimation o the cost o one-litre distillate ater has been made. In addition to the capital cost (P) o the hybrid solar still, other parameters such as sinkin und actor (SFF), annual salvae value (SV), annual maintenance cost (MC), and interest rate per year should be also considered. t this stae, the Capital recovery actor (CRF) is deined in terms o the interest per year i and also the number o lie years o the system n [13,14] CRF = i( 1+ i) n ( i) n 1+ 1 (11) he interest per year i and the number n o lie years o the system are assumed 12% and 10, respectively. Fixed annual cost (FC) becomes: FC = P(CRF) (12) Where, P is the capital cost o solar still. he capital cost includes the cost o the hybrid solar still and air compressor as ell as the costs o labor cost ( or the active system). In this ork the capital cost P becomes 1026.$ By takin the salvae value o system S equal to 20% o capital expressed respectively as [15]: SFF = i n 1+ 1 ( i) (13) Sinkin und actor (SFF) and annual salvae value (SV) can be

6 ith an ir Compressor SV = ( SFF) S (14) For, S = 0.2P (15) Sinkin und actor (SFF) and annual salvae value (SV) can be or the passive unit, and $ (by considerin $ or the pump price) or the active one. he MC hich is annual maintenance operational cost o the system consists o collectin the resh ater, cleanin the lass cover, ashin inside the unit to remove the deposited salt, and maintenance o DC an. Here, 15% o ixed annual cost is considered as maintenance cost: MC = 0.15( FC) (16) hereore the annual cost (C) is: C = FC + MC SV (17) Finally, the cost o resh ater per liter can be calculated as: C CPL = (18) M Where M is the averae annual yield o the solar still, Cost per liter o resh ater is shon in able.3 or the hybrid distiller unit ith and ithout an air compressor. ype o distiller With air compressor Without air compressor able 3: Distilled ater cost calculation nnual production, K Fiure 2: Variation o experimental solar lux ith rue Solar ime Variation o ater temperature at a dierent lo rate o air ith respect to the time is shon in Fi. 3. It shos that the ater temperature initially increases as solar radiation increases and urther decrease as per the incident radiation. VI. nnual cost ($) Cost per liter o resh ater/$ Result and Discussion Durin orkin hour incident solar radiation on lass cover surace as recorded ith the help o pyranometer or dierent air velocity durin the test days, shon in Fi.2. It is observed that the maximum solar incident radiation on lass cover durin 12 h and 14 h around 900 W/m ² or all air velocity. 35 Global Journal o Researches in Enineerin ( ) Volume XVII Issue III Version I

7 Global Journal o Researches in Enineerin ( ) Volume XVII Issue III Version I ith an ir Compressor 36 Fiure 3: Variation o ater temperature at a dierent lo rate o air ith respect to time he temperature o ater raned rom 45.7 C to 89 C ith airlo rate 0.06 k/s and reaches its maximum value at 13 hours. It has been observed that the temperature o ater starts to decline ith air lo rate increases (70 C). Whereas lass temperature decrease due to the enrichment o air lo rate. Fiure 4: Variation o convective heat transer coeicient at a dierent lo rate o air ith respect to time

8 he convective heat transer coeicient beteen the ater surace and the loin air at a dierent lo rate o air has been evaluated and shon in Fi.4. Maximum heat convective heat transer coeicient is recorded W/m² C, 0.42 W/m² C, W/m² C and 1.25W/m² C at air lo rate o 0.01 k/s, 0.03 k/s, 0.05 k/s and 0.06 k/s respectively. It has been recorded %, 40.81%, and 10.83% hiher as compared to the air lo rate o 0.01 k/s, 0.03 k/s, and 0.05 k/s respectively. Convective heat transer coeicient at an air lo rate o 0.06k/s ill maintain its lead throuhout the experimentation hich causes to hiher yield as compared to the loer mass lo rate o air. he convective heat transer coeicient beteen the ater surace and the loin air at a dierent lo rate o air has been evaluated and shon in Fi.3. Maximum heat convective heat transer coeicients are recorded W/m² C, 0.42 W/m² C, W/m² C and 1.25W/m² C at air lo rate o 0.01 k/s, 0.03 k/s, 0.05 k/s and 0.06 k/s respectively. It has been recorded %, 40.81%, and 10.83% hiher as compared to the air lo rate o 0.01 k/s, 0.03 k/s, and 0.05 k/s respectively ater the third hour o the time. Convective heat transer coeicient at an air lo rate o 0.06k/s ill maintain its lead throuhout the experimentation hich causes the hiher yield in comparison ith the loer mass lo rate o air. ith an ir Compressor 37 Fiure 5: Variation o evaporative heat transer coeicient at a dierent lo rate o air ith respect to time Variation in the evaporative heat transer at dierent air lo rate o air at a one-hour interval o time is evaluated and shon in Fi.5. Which clearly shos that evaporative heat transer coeicient durin the mass lo rate o air 0.06 k/s is hiher as compared to the loer lo rate o air. It also depicts that enhancement o the lo rate o air ill boost the evaporative heat transer coeicient hich results in hiher yield. n evaporative heat transer coeicient record 74.4%, 35.19% and 24.57% hiher at lo o air 0.06 k/s as compared to the air lo rate o 0.01 k/s, 0.03 k/s and 0.05 k/s respectively. Global Journal o Researches in Enineerin ( ) Volume XVII Issue III Version I

9 Global Journal o Researches in Enineerin ( ) Volume XVII Issue III Version I ith an ir Compressor 38 Fiure 6: Variation o yields due to dierent air lo rate ith respect to time Eect on the yield o active solar still hybrid ith an air compressor ith correspondin time interval is shon in Fi.6. ater a one-hour interval o time test-ri ed ith an air o 0.06k/s maintain a siniicant lead in distillate out as compare to the other those are ed ith a loer lo rate o air. hrouhout experimentation hybrid solar still interated ith an air compressor ed ith 0.06k/s air lo rate maintain its superiority over the others and maximum yield recorded 0.6 k/h, 0.2k/h, 0.25k/h and 0.35k/h at an air lo rate o 0.01 k/s, 0.03 k/s, 0.05 k/s and 0.06 k/s respectively. t eihth hour interval o time test ri hich has air lo rate o 0.6 k/s ill ive %, 13.3% and 94.44% hiher yield as compared to the other cases o 0.01 k/s, 0.03 k/s, and 0.05 k/s respectively. Nomenclature VII. Conclusion Inluence o variation in air velocity ithin the hybrid solar still ill reatly inluence the production rate o the nely developed hybrid solar still. he rate o heat and mass transer is enhanced due to the ormation o ater bubbles ithin the distiller unit hereas all in basin ater temperature observed due to increase in ind lo rate. But the overall productivity o distiller unit as siniicantly improved as compared to hybrid solar still ithout air. Cp: speciic heat o air, J/kK h c : Convection heat transer coeicient, W/m.K h e : Evaporative heat transer coeicient, W/m.K hm: Mass heat transer coeicient, W/m.K k : hermal conductivity.w/m.k L: Speciic lenth, m L v : latent heat, W/k M: Molar eiht, mol/ me : Speciic mass, k/m Nu: Nusselt Number Re : Reynolds Number P : Pressure, N/m 2 Pr : Prandtl Number S: Surace, m² : Water temperature, ºC : Glass temperature, ºC Induce a : air b : basin c : Convection, e : Evaporator : Glass : Water symbol ρ: Relectivity β : Inclination µ : dynamic viscosity KJ/m K : dierence λ : hermal conductivity W/m K Cost nomenclature s: rea o basin in solar still m 2 C: nnual cost MC: nnual maintenance operational cost o the system SV: nnual salvae value CPL: Cost o resh ater ($/lit) CRF: Capital recovery actor NNEXURE ppendix : Physical characteristics o humid air

10 ith an ir Compressor ( ) 0.38 Lv = 2.569x10 5 ( 1 ) C p = λ = x10 ρ ρ = = μ = 1.718x10 Reerences Réérences Reerencias x W.. Qureshi, N.K.C. Nair, M.M. Farid. Impact o enery storae in buildins on electricity demand manaement. Enery Conversion and Manaement 52 (2011),pp G.C.Pandey Eect o dried and orced air bubblin on the radial pressure o ater vapour and the perormance o solar still Solar Enery 33 (1984), p p F.. l-sulaiman, M.I. Zubair, M. ti, P. Gandhidasan, S.. l-dini, M.. ntar, Humidiication dehumidiication desalination system usin parabolic trouh solar air collector, ppl. herm. En. 75 (2015), pp K. Srithar,.Rajaseenivasan Perormance analysis on a solar bubble column humidiication dehumidiication desalination system processus saety and environnemental protection 105 (2017), pp E. Kabeel,M.H. Hamed, Z.M. Omara, S.W. Sharshir, Experimental study o a humidiicationdehumidiication solar technique by natural and orced air circulation, Enery 68 (2014),pp S.. El-ouz. ne process o desalination by air passin throuh seaater based on humidiication - dehumidiication process. Enery 35 (2010), pp Rajaseenivasan, K. Srithar, Potential o a dual purpose solar collector on humidiication dehumidiication desalination system, Desalination 404 (2017), pp E. Kabeel, M. bdelaied, M. Mahoub, he perormance o a modiied solar still usin hot air injection and PCM, Desalination 379 (2016), pp S.. Nadaa, H.F. Elattara,. Foudab, Perormance analysis o proposed hybrid air conditionin and humidiication dehumidiication systems or enery x x savin and ater production in hot and dry climatic reions, Enery Conversion and Manaement 96 (2015), pp Ghazy, H.E.S. Fath, Solar desalination system o combined solar still and humidiication dehumidiication unit, Heat Mass rans. (2016) 11.. John Duie,. William Beckman Solar Enineerin o hermal Processes Solar Enery Laboratory University o Wisconsin-Madison Copyriht 2013 by John Wiley & Sons, Inc. ll rihts reserved 12. K. Hidouri, S. Gabsi Correlation or Leis number or evaluation o mass lo rate or simple/hybrid solar still. Desalination and Water reatment 57, pp.1 8, J.. Esahani, N. Rahbar, M. Lavva. Utilization o thermoelectric coolin in a portable active solar still - n experimental study on inter days. Desalination 2011;269:198e E. Kabeel,.M. Hamed, S.. El-ouz. Cost analysis o dierent solar still coniurations. Enery 2010;35:2901e8. 3 ( 2 ) ( 3 ) ( 4 ) ( 5 ) ( 6 ) 39 Global Journal o Researches in Enineerin ( ) Volume XVII Issue III Version I

11 Global Journal o Researches in Enineerin ( ) Volume XVII Issue III Version I ith an ir Compressor 40 his pae is intentionally let blank