Evaluating the Effect of New Local Materials of Evaporative Cooling Pads

Transcription

1 Americn-Eursin J. Agric. & Environ. Sci., 5 (): 78-84, 05 ISSN IDOSI Pulictions, 05 DOI: 0.589/idosi.ejes Evluting the Effect of New Locl Mterils of Evportive Cooling Pds Egl Elmsd nd Adelnser Omrn Deprtment of Agriculturl Engineering, Fculty of Agriculturl Sciences, University of Gezir, Wdmedni, Sudn School of Economics, Finnce nd Bnking, College of Business, Universiti Utr Mlysi, 0600, Sintok, Kedh, Mlysi Astrct: The present study imed to evlute the fesiility of celdek pds, luff pds, strw fier pds nd sckcloth pds s lterntive pd mterils. Experimentl mesurements were conducted nd the experimentl dt were quntittive. The experimentl work minly focused on the effects of different types nd thicknesses of evportive cooling pds when used for chnging the environmentl conditions inside greenhouses. Moreover, the experimentl work involved the mesurement of environmentl prmeters viz., temperture, reltive humidity, ir velocity nd pressure drops t different times during the dy, using the different thickness prmeters of the evportive cooling pds i.e., 50, 00 nd 50 mm nd the wter flow rtes through the pds. The dt otined from the experiments nd mesurements were nlyzed using Sttisticl Pckge for the Socil Sciences Results deciphered tht there ws significnt difference etween evportive cooling pd types nd cooling efficiency. The Luff pds yielded n verge sturtion of 73.67%, wheres other pds yielded the following verge sturtions: strw fier pds 7.87%, celdek 70.33% nd sckcloth 69%. However, there ws highly significnt difference etween the pd thickness nd cooling efficiency. The results otined for environmentl fctors, indicted tht there ws significnt difference etween environmentl fctors nd cooling efficiency. In terms of the effect of ir velocity on sturtion efficiency nd pressure drop, higher ir velocity decreses sturtion efficiency nd increses pressure drop cross the wetted pd. Finlly, the present study indicted tht the luff pds perform etter thn the other evportive cooling pds nd hve higher potentil s wetted-pd mteril. Key words:greenhouses Temperture nd humidity Heting nd ventiltion Greenhouse technology Greenhouse pplictions INTRODUCTION such s cron dioxide, temperture, reltive humidity, light nd rdition. Greenhouses offer etter A greenhouse is structure used for protecting possiility for the off-seson production of mny crops plnts from dverse climtic effects nd for supplying []. The increse in ir temperture inside greenhouse fvorle environment for plnt production. with previling high outdoor ir temperture in the This technique is necessry to overcome the high hzrds tropics will stress the greenhouse crops [3]. Thus, of open field production, such s high rinfll, inters solr lowering the ir temperture is mjor concern for tropicl rdition, weed rivlry, s well s dmges cused y greenhouse climte mngement. During the hot seson, diseses, insects, high temperture nd reltive humidity the temperture of mient ir inside greenhouses nd []. Therefore, in such regions, the reduction of ir niml houses increses to over 40 C ecuse of therml temperture inside greenhouse or the regultion of the stress [4]. In greenhouses, therml stress negtively temperture closer to the mient temperture during ffects the emergence, stem strength, flowering nd fruit summer is necessry for successful crop production. set nd sizes of seedlings. High ir tempertures in niml The growth conditions in greenhouse system re houses decreses feed consumption, weight gin nd usully chieved y monitoring effective growth fctors, milk nd egg yields of nimls [5]. In severl countries, Corresponding Author: Egl Elmsd, Deprtment of Agriculturl Engineering, Fculty of Agriculturl Sciences, University of Gezir, Wdmedni, Sudn. E-mil: nser_elmroni@yhoo.co.uk. 78

2 Am-Eurs. J. Agric. & Environ. Sci., 5 (): 78-84, 05 the trend of using fn-pd evportive cooling systems in griculturl uildings is incresing, ut the rte of this increse is inhiited y the high costs of commercil pd mterils [5]. The use of evportive cooling pds is relile method ut requires the gretest power consumption. Evportive cooling systems re sed on the exchnge of evported wter from sensile het to ltent het, where wter is supplied mechniclly. The decrese in ir temperture is due to the evportion of wter in ir. Thus, temperture decreses with incresing humidity, while the enthlpy of ir remins constnt during the process. Fn pds, fogging systems nd roof evportive cooling re some of the current evportive cooling methods [6]. Commercilly ville cooling pds re expensive nd ccordingly, there is n urgent need to evlute the performnce of suitle loclly ville mterils when used s cooling pds, prticulrly for rurl griculturl uildings. In fct, mny studies were crried out to evlute the use of loclly ville mterils s cooling pds, such s: expnded cly, swdust, vegetle fier nd col [7], discrded cly ricks, corn-co nd chrcol [8]; ground sponge, stem sponge, jute fier nd chrcol [9]. Moreover, the reported efficiency of some loclly ville mterils ws 79% for chrcol, 48% for hzelnut rind nd 96% for wood shvings [0]; 89.6 to 9.8% for coir fier []; 47.% to 85.5% for fine fric nd to 86.3% for corse fric [5]; 39.9% for plm fier, 6.% for jute []. Cellulose pds expnded cly nd vegetle fier were recommended s pd mterils for evportive cooling systems y Tncoco et l. [7]. On the other hnd nd ccording to the results of the study y Dzivm et l. [9], stem sponge showed superior pd mteril qulities compred to ground sponge, jute fier nd chrcol. Gunhn et l. [3] evluted the suitility of some locl mterils such s pumice stones, volcnic tuff nd greenhouse shding net s cooling pds. They found tht volcnic tuff ws good lterntive pd mteril. It gve n evportive sturtion efficiency of 63-8%. Ahmed et l. [4] studied sliced wood, strw nd celdek cellulose s mterils for evportive cooling pds. Sliced wood pds hve more cooling efficiency nd crop productivity under greenhouse conditions. From the reserch studies mentioned ove, it ecome cler tht there re no studies out luff nd strw fier nd sckcloth s wetted pd mterils. In ddition, oth pds mterils mentioned ove re low cost nd esy-to-find in world. Therefore, we consider using those mterils s evportive cooling pd in terms of sturtion efficiency nd pressure drop cross wetted pd. Therefore the present study minly ims to study the evportive cooling efficiency nd environmentl fctors of celdek pds, luff pds, strw fier pds nd sckcloth pds s wetted pds in evportive cooling system. In order to chieve this im, the following ojectives re proposed: To determine the effects of different types nd thicknesses of locl evportive cooling pds on the cooling efficiency inside greenhouse. To ssess the optimum wter flow rte for the different types nd thicknesses of the selected evportive cooling pds. MATERIALS AND METHODS Sudn is locted in the northest prt of the Africn Continent, hs mny sttes, this study in Gezir stte, it is locted in centrl Sudn etween Blue Nile flowing est from Tnh lke from Ethiopi nd white Nile flowing westfrom Victori from Ugnd. This study ws conducted in the Gezir University in Wdmedni town, Gezir Stte, Sudn (4 3'N, 33 9'E, 405 m ove se level) (Fig. ). Fig : Mp of repulic of Sudn showing the loction of Wedmedni. Source: 79

3 Am-Eurs. J. Agric. & Environ. Sci., 5 (): 78-84, 05 To chieve the ojectives of this reserch endevor points including dry ul temperture nd the reltive n experiment ws crried out to evlute the effects on humidity of ir. In ech section there were five cooling efficiency of greenhouses when using different hygrometers nd ll hygrometers were clirted efore types nd thickness of locl evportive cooling pds recording the dt of temperture nd reltive humidity nd lso the effect on environmentl fctors such s inside nd outside. Air velocity in the wind duct ws temperture, reltive humidity, ir velocity nd pressure mesured y vne-type nemometer. Its mesuring rnge drops nd lso effect of the wter quntity during the ws 0.7 to.75ms nd ccurcy ws ±0 ms summer period. The experimentl work ws minly Anemometer ws plced 500 mm wy from the fce of concerned out the effect of types nd thickness of the pds. The sttic pressure drop of the irflow during evportive cooling pds (nmely: celdek cellulose, the pssing through the pd medi ws mesured y strw fier, Sckcloth pds nd luff sponges pds), using Anemometer ll these devices were clirted when used to chnge environmentl conditions inside efore testing strted. The cross-sectionl shpe of the ir the greenhouses. All experiments were conducted in duct ws hollow rectngle. The surfces of the duct stedy stte nd ll of the tests were chieved in triplicte. were mde of trnsprent Plexigls sheet for esy viewing, The experimentl work involve mesurement of oth inside of the duct hs cross-section of 300 mm y 300 environmentl prmeters (temperture nd reltive mm nd length of wind duct ws.5 m n xil suction humidity nd ir velocity nd evportive cooling pds fn of 500 mm dimeter driven y 3-phse electric motor using [celdek cellulose (CP), strw fier (SP), Sckcloth ws fitted t one end of the duct nd the distnce pds (SP) nd Luff sponge pds (LSP)] s wetted pds etween the fn nd dischrge fce of the pd ws m. medi with different thickness i.e., 50, 00 nd 50mm The velocity of the inside ir of wind duct ws controlled nd wter flow rtes through the pds nd four y chnging the rottionl speed of the fn. levels of ir suction velocity viz., 0 7, 0, 5, 75 m s. The mesurements were tken from 0 m to 3pm during Experimentl Procedures: The experiments to determine the dy, this periodrepresents themximum the effects of types nd thickness nd wter flow rte, ir temperturesinsummer were investigted. Ech pd velocity on the evportive cooling efficiency of the mteril ws filled independently in especilly glvnized selected pd medi viz., celdek cellulose (CP), strw fier iron frmes to mke n evportive seled unit. (SP), Sckcloth pds (SP) nd Luff sponge pds (LSP) The thicknesses were 50, 00 nd 50 mm. The front nd were crried out t four levels of ir velocity i.e. 0 7, 0, the ck fces of the crtridges were covered with iron 5, 75 m s nd three levels of pd thickness i.e. 50, wire sieve nd it size ws 0mm y 0mm during the tests, 00, 50 mm were studied. The evportive sturtion mesurement sections nd evportive pd seled units efficiencies of the pd medi were determined y using were inserted into specil frmes tht were plced in the the eqution. wind duct nd the connection edges seled ginst ir escpe ndthe other prt ofthe wind ductexposed Sttisticl Anlyses: Anlysis of collected dt ws ofoutdoor irconditions,so tht theirinsideof the crried out y Sttisticl Pckge for the Socil Sciences ductndpssingon the pdsis the sme sthe outside ir. (SPSS) softwre version 6. One wy ANOVAs nd The wter inlet ws fixed on the top of this frme nd the multiple regression nd correltion nlysis were crried wter ws distriuted over the upper fce of the out to determine the level of significnce nd comined evportive pd seled unit y tue, the wter evenly effect of the prmeters (thickness, wter flow rte nd onto the pd fce. During the experiments, drined wter pressure drops) on the evportive sturtion efficiency ws collected in tnk nd re-circulted y centrifugl of the pd medi. pump. The evportive pds were wetted efore ech test nd the recording of the mesured dt ws Stedy Stte of Anlysis of Cooling Concepts: strted t lest 0 min fter ech test run strted. Therml cooling of greenhouse is required in the cse The cooling efficiency ws mesured tunnel system of excess het trpped inside the greenhouse. An excess under stedy-stte condition. The test section ws het trpped inside the greenhouse minly depends on designed to ccommodte 50, 00 nd 50 mm thick seled month of the yer. The levels of cooling depend on the units of the test pds. Mesurement sections were spced month of yer. For more effective cooling other concepts 500 mm prt from ech fce of the pd seled units. nmely roof, pd- fn cooling nd erth ir het exchnger Ech mesurement section contined the mesuring etc. Group one first zone includes (5. Chmer room, 80

4 Am-Eurs. J. Agric. & Environ. Sci., 5 (): 78-84, Air inlet, 7.motor push the ir, 8. Thermo hygrometers, pd re completely nd thoroughly. Fig. shows tht LP 9. Wter meter, 0. Wter outlet,. Pump,. Wter tnk, produced higher wter flow rte, followed y SP, CP nd 3. Pds frme). Group two second zone include (. Power SP. These results re in line with those reported y input (motor),. Exhust fn, 3. Anemometers, 4. Wter Dzivm et l. [9], wherein the cooling efficiency is inlet (wter pipe). incresed with incresing wter flow rte until the pds re suitly moist. This result lso supports the ide of Evportive Cooling Efficiency: This is defined s the Gunhn et l. [3] tht is; the mount of the selected rtio of the ctul dry- ul temperture reduction to the wter flow rtes is enough to wet the pds completely nd theoreticl mximum t 00%. ASHRAE [5] showed tht thoroughly. A significnt difference ws found etween the efficiency is the ility to ccess coolnt temperture ll different thicknesses of evportive cooling pds nd dry ir pssing to the temperture wet or is the ility to cooling efficiency (p < 0.0) (Fig. 3). This result could e ccess the coolnt on the ir pssing through it to the ttriuted to the increse in evportive cooling sturtion stte. It is clculted s the following eqution: pdthickness tht incresedthepssing time of ir nd therefore reducedthe speed ofthe irflow nd decresed T - T T - T µ = 00 Where: w pd porosity. Gunhn et l. [3] otined similr results. () However, the increse in the rte of wter flow incresed the reltive humidity nd reduced the surfce re exhiition to the ir from the inlet. µ = evportive sturtion efficiency in %. Effect of Evportive Cooling Thickness: The result T = inlet dry ul temperture C. indicted tht there ws high significnt reltionship T = outlet dry ul temperture C. etween cooling pd thickness nd cooling efficiency T w = wet ul temperture in C. (r = 0.97, p < 0.0). In ddition, pd thickness ws found to hve significnt reltionship with most of the The vlues of the T w were determined y using environmentl prmeters nd cooling pd thickness psychometrics chrt. showed positive reltionship with reltive humidity, wter quntity nd pressure drop. Incresing pd density RESULTS AND DISCUSSION improves the overll porosity nd cpillrity of the cooling pd, therey producing uniform distriution of Effect of Wter Flow Rte on the Cooling Efficiency of wter. However, higher wter flow nd high resistnce to Different Pd Types nd Thickness: The wter rte flow ir flow is required. These results re in greement with selected in the present study showed significnt effect the study on evportive cooling pd systems on cooling efficiency t 0.0 proility level. The mount reported y Dhi [6]. Temperture, ir velocity nd of the selected wter flow rtes ws enough to wet the thickness inside the greenhouse were negtively Fig : Scheme of Stedy Stte.. Power input (motor),. Exhust fn, 3. Anemometers, 4. Wter inlet (wter pipe), 5. Chmer room, 6. Air inlet, 7.motor push the ir, 8. Thermo hygrometers, 9. Wter meter 0. Wter outlet,. Pump,. Wter tnk, 3. Pds frme. 8

5 Am-Eurs. J. Agric. & Environ. Sci., 5 (): 78-84, 05 Tle : The effect of pds thickness on cooling efficiency. Evportive sturtion efficiency % Thickness mm Celdek Strw fier Luff Sckcloth c 80 c 78 d 89 c 80 *The vlues with sme letter not significntly difference t proility, p< 0.0. Fig 3: The effect of wter flow rte on cooling efficiency ccording to pds types. Fig 4: The effect of wter flow rte on cooling efficiency ccording to thickness. correlted. The sturtion efficiency decresed with incresing ir velocity nd pd thickness. In ddition, wetted pds with 50 mm thickness resulted in etter sturtion efficiency compred with those of 50 mm nd 00 mm thickness ecuse wetted pds with 50 mm thickness provide higher contct surfce re etween ir nd wter. Lower ir velocity provides more time for the ir to contct nd sor the wter from the surfce of wetted pds. Thus, reducing ir temperture nd incresing wter evportion provides higher sturtion efficiency. These results re lso in line with those presented y Lio nd Chiu [5]. Effect of Evportive Cooling Pds Types on Cooling Efficiency: Tle shows the regression nlysis used to evlute the effect of cooling pd types on cooling efficiency inside the greenhouse. The type of cooling pd ws found to hve significnt effect on cooling efficiency inside the greenhouse. The type of cooling pd ws found to e significnt prmeter in predicting the cooling efficiency inside the greenhouse. Therefore, cooling is 00% nturl cooling process ccomplished y the evportion of wter into ir. Wter is llowed to Tle : Effect of cooling pd types on cooling efficiency. B t Sig. VIF Types R 0.98 F Sig. F Durin-Wtson 0.88 flow down the pds t the sme time s dry outside ir is pulled cross the pds, producing cool nd fresh ir. The unique flute design of the pds permits very high surfce re of the wter to encounter n eqully high surfce re of ir, therey resulting in very high evportion rte. This evportion efficiency is s high s 9% with 50 mm thick pds, which llows for lrge drop in dry ul temperture s the energy required to evporte the wter into the ir is tken from the ir. The drier the outside ir, the etter the cooling effect chieved nd the higher the humidity of the outside ir, the lower the resultnt cooling effect [7]. Effect of Evportive Cooling Pd Types on Environmentl Prmeters: Tle 3 proves tht cooling pd types significntly ffect other environmentl prmeters inside the greenhouse. Cooling pd types ffected pressure drop (.9%), wter quntity nd temperture inside the greenhouse. Effect of Environmentl Indoor Prmeters on Cooling Efficiency: The results otined re shown in Tle 4. Environmentl prmeters explined 74.% of the cooling efficiency inside the greenhouse. In ddition, ll prmeters inside the greenhouse significntly ffected cooling efficiency. These prmeters include temperture, reltive humidity, wter quntity, pressure drop nd ir velocity inside the greenhouse. Regression nlysis to exmine the effect of environmentl prmeters on cooling efficiency inside the greenhouse ws lso shown in Tle 4. It is found tht environmentl prmeters explined 74.% of cooling efficiency inside the greenhouse (R = 0.74, F= , p<0.0). However, it ws lso found tht ll prmeters inside the 8

6 Am-Eurs. J. Agric. & Environ. Sci., 5 (): 78-84, 05 Tle 3:Effect of cooling pd types on environmentl prmeters. Prmeters R F Sig. F B t Sig. T in RH in WFR AV in P * Correltion is significnt t the 0.0 level (- tiled). Tle 4: Effect of environmentl prmeters to cooling efficiency. B t Sig. VIF T in RH in WFR AV in P R 0.74 F Sig. F Durin-Wtson 0.67 *Correltion is significnt t the 0.0 level (-tiled). greenhouse cn e significnt predictor on cooling efficiency, tht re temperture inside the greenhouse (B= -.64, t= , p<0.0), Reltive humidity inside the greenhouse (B= 0.379, t=3.665, p<0.0) nd wter quntity (B= 0.3, t= 3.709, p<0.0), drops pressure inside the greenhouse (B=0.35, t=3.6, p<0.0) nd ir velocity inside the greenhouse (B= 0.44, t=.598, p<0.0). Suitle Evportive Cooling Pd Medi for Cooling Efficiency: Generlly, n evportive cooling pd system must reduce the ir temperture to the preferred point using the lest power consumption nd expenses. Thus, the suitle pd medi must hve the highest evportive cooling efficiency nd lowest irflow resistnce. Thus, when choosing the optiml pd medi for cooling systems of griculturl uildings, the evportive efficiency nd resistnce ginst irflow of the pd mterils must e considered. The dt on the highest evportive cooling efficiency nd working condition of the selected pd mterils. ACME [8] reported tht high cpcity fns used for ertion nd ventiltion of glsshouses nd poultry houses generlly generte totl pressure of pproximtely 30 P. This sitution must e tken into considertion when selecting pd mterils for evportive cooling system of these uildings. In ll test conditions, the pressure drop vlues of the ir through SP were oserved to e less thn 30 P, wheres the other pds hd high vlues more thn 30 P. CONCLUSION In conclusion, nlysis shows tht the pd type significntly ffects the cooling efficiency. Luff pds (LPs) hd higher sturtion efficiencies compred with the strw fier (SP), celdek (CP) nd sckcloth (SP) pds. Moreover, the current study proves tht pd thickness lso hs highly significnt effect on cooling efficiency. The results show tht thicker pds of 50 mm hve efficiencies higher thn those of 50 nd 00 mm. With regrd to the second ojective, the results indicte tht most environmentl fctors, prticulrly temperture nd pressure drops, significntly ffect the performnces of different pd types. Moreover, the current study shows highly significnt reltionship etween pd thickness nd ll environmentl fctors. Pd type, wter flow rte nd pd thickness were proven to ffect efficiency. The efficiency incresed when the pd thickness nd wter flow rte were incresed. Moreover, it ws found to e significntly relted to other environmentl fctors, such s temperture nd reltive humidity. It incresed when the pressure drops nd ir velocity incresed. The focus of the current pper is on the effect of environmentl fctors on cooling efficiency nd the evlution of new mterils tht could e used s locl evportive cooling pds. The following re herey recommended for future studies. LPs for cooling greenhouses should e used for the following resons: () to provide etter temperture nd reltive humidity conditions, pressure drops nd wter flow rtes inside greenhouses; nd () to chieve the est sturtion efficiency. ACKNOWLEDGEMENTS The uthors would like to cknowledge the support which is given y The World Acdemic of Sciences (TWAS) orgniztion nd we would lso like to express our thnks to Dr. Mohd Rodzi Ismil from school of Housing Building nd Plnning, Universiti Sins Mlysi for support nd guidnce. REFERENCES. Shrm, A.K. nd V.M. Slokhe, 006. Greenhouse Technology nd Appliction. First edition, Agrotech Pulishing Acdemy: Englnd.. Al-Amri, A., 000. Comprtive Use of Greenhouse Covers Mterils nd their Effectiveness in Evportive Cooling in Estern Province of Sudi Ari. Agricu. Mech. in Asi, Afric nd Ltin Americ, 3():

7 Am-Eurs. J. Agric. & Environ. Sci., 5 (): 78-84, Luo, W.H., J. DeZwrt, S. Di, C. Wng nd. Lio, C.M., S. Singh nd T.S. Wng, 998. C. Bu, Stnghellini, 005. Simultion of greenhouse Chrcterizing the Performnce of Alterntive mngement in the sutropics, Prt I: Biosystems Evportive Cooling Pd Medi in Therml Engineering, 90(3): Environmentl Control Applictions. J. Environ. 4. Öztürk, H.H., 003. Evportive Cooling Efficiency Sci.& Hel., 33(7): of Fogging System for Greenhouses. Turkish J.. Al-Sulimn, F., 00. Evlution of the Performnce Agricu. Forest, 7: of Locl Fiers in Evportive Cooling. Ener. 5. Lio, C.M. nd K.H. Chiu, 00. Wind Tunnel Convers. Mnge., 43: Modeling the System Performnce of Alterntive 3. Gunhn, T., V. Demir nd A.K. Ygcioglu, 007. Evportive Cooling Pds in Tiwn Region. Evlution of the Suitility of Some Locl Mterils Building Environment, 37: s Cooling Pds. Biosys. Eng., 96: Gnguly, A. nd S. Ghosh, 0. A review of 4. Ahmed, E.M., O. As, M. Ahmed nd M.R. Ismil, Ventiltion nd Cooling Technologies in Agriculturl 0. Performnce Evlution Three Different Types Greenhouse Appliction. Irnic J. Ener. Environ., of Locl Evportive Cooling Pds in Greenhouses in (): Sudn. Sudi J. Biol. Sci., 8: Tinoco, I.F., J.L. Figueiredo, R.C. Sntos, 5. ASHRAE, 983. Method of Testing for Rting J.N. d Silv, T. Yngi, M.O. de Pul,, N.L. Puglisi, Room Air Conditioners nd Pckged Terminl Air R.B. Vigoderis nd M.B. Corderio, 00. Comprison Conditioners,Hndook. of the cooling effect of different mterils used in 6. Dhi, A., 996. Computer-ided Design for evportive pds. Cmpins, Brzil, pp: Evportive Cooler Systems nd Estimting Numer 8. Chunchi, W., 998. Appliction of Discrded Cly of Air Coolers in Poultry Houses. Agricu. Mechni. Brick nd Chrcol s Cooling Pd Mteril for Diry in Asi, 7: 4. Stnchin Brn. Disserttion. Retrieved August9, 7. Metin, D., C. Tekin, Y. Krc, Y. Ilmz, B. Ali, P. Cetinçelik. Ömer nd Çukurov, 0. The Effects 9. Dzivm, A.U., U.B. Bindir nd F.O. Ao, 999. of Air Velocity on the Performnce of Pd Evlution of Pd Mterils in Construction of Evportive Cooling Systems. Adn, Turkey. Active Evportive Cooler for Storge of Fruits nd Africn J. Agricu. Rese., 6(7): Vegetles in Arid Environments. Agricu. Mechni. 8. ACME, 995. The Greenhouse Climte. Engineering in Asi, 30(3): nd Mnufcturing Corp. Muskgee, Hndook. 0. D tekin, M., G.A.K. Gürdil, Y. Yýldýz nd A.N. Uluock, 998. A reserch on Determintion of the Efficiency of The Different Type Pd Mterils of Using in Evportive Cooling System (fn-pd) in Poultry Houses. Proceedings, Trýmsl Meknizsyon 8, Ulusl Kongresi, pp: