Experimental study of a hybrid solar collector using TiO2/water nanofluids

Ci a ion: Elango an, M.; S imanickam, B.; ˇ Cep, R.; Sa anya, A.; Ramachand an, M. Expe imen al S udy o a Hyb id Sola Collec o Using TiO2/Wa e Nano luids. Ene gies 2022,15, 4425. h ps:// doi.o g/10.3390/en15124425 Academic Edi o s: Gianpie o Colangelo and Geo ge Kosmadakis Recei ed: 21 May 2022 Accep ed: 16 June 2022 Published: 17 June 2022 Publishe ’s No e: MDPI s ays neu al wi h ega d o ju isdic ional claims in published maps and ins i u ional a il- ia ions. Copy igh : © 2022 by he au ho s. Licensee MDPI, Basel, Swi ze land. This a icle is an open access a icle dis ibu ed unde he e ms and condi ions o he C ea i e Commons A ibu ion (CC BY) license (h ps:// c ea i ecommons.o g/licenses/by/ 4.0/). ene gies A icle Expe imen al S udy o a Hyb id Sola Collec o Using TiO2/Wa e Nano luids Muniyandy Elango an 1,* , Baska an S imanickam 1, Robe ˇ Cep 2,* , Ami ha ajan Sa anya 3 and Manickam Ramachand an 4 1Depa men o Mechanical Enginee ing, Vel Tech Ranga ajan D . Sagun hala R&D Ins i u e o Science and Technology, Chennai 600062, India; [email p o ec ed] 2Depa men o Machining, Assembly and Enginee ing Me ology, Facul y o Mechanical Enginee ing, VSB-Technical Uni e si y o Os a a, 708 00 Os a a, Czech Republic 3Depa men o Physics, Vel Tech Ranga ajan D . Sagun hala R&D Ins i u e o Science and Technology, Chennai 600062, India; [email p o ec ed] 4Da a Analy ics Lab, REST Labs, Ka e ipa inam, K ishnagi i 635112, India; [email p o ec ed] *Co espondence: [email p o ec ed] (M.E.); [email p o ec ed] (R. ˇ C.) Abs ac : A case s udy o sola collec o ou doo es o he expe imen al echnique conduc ed a A adi, Chennai. To lowe he empe a u e o sola PV panels, wa e , and wa e -based nano luids we e u ilized concu en ly. Highe cell empe a u es es ic he e ec i eness o sola PV sys ems since only a mino amoun o powe om he sun is ga he ed as elec ici y om he ene gy con e sion, and he emaining ene gy is squande ed as hea . The s udy aimed o de elop and build a hyb id collec o while also analyzing i s elec ical and he mal ene gy pe o mance. The e o was in es ed in imp o ing he sys em’s pe o mance; he PVT collec o was es ed a olume concen a ions o wo, such as 0.5 and 1.0 L pe minu e (LPM). The PV/T collec o de e mined he mal e iciency as highes was 48.38 pe cen and 54.03 pe cen , espec i ely, a 0.5 LPM and 1.0 LPM o olume low a es. The PV/T collec o ’s highes elec ical e iciency was 18.32 pe cen and 19.35 pe cen , espec i ely, o 0.5 LPM and 1.0 LPM o olume low a es. The esul s demons a e ha nano luid has mo e excellen he mal conduc i i y han a base luid wi h a li le change in he luid iscosi y and densi y. Keywo ds: s andalone hyb id collec o ; TiO 2 ; low a e; nano luid; he mal pe o mance; elec ical; ene gy; enewable 1. In oduc ion The inc ease in global ene gy equi emen s e e y yea , and he g adual deple ion o adi ional uels necessi a es echnological ad ancemen s based on al e na i e ene gy sou ces [ 1 ]. Sola collec o s o indus ies and households a e equen ly used o hea wa e wi h sola ene gy. Ou o wo collec o s, one is called a Sola la pla e collec o and he o he is called an e acua ed ube collec o . To inc ease p oduc i i y, wo di e en powe con e sion sys ems, known as hyb id powe o pho o ol aic he mal sys ems, can be coupled oge he [ 2 , 3 ]. Sola enewable ene gy is a popula enewable sou ce because i is ee, easible, du able, has a low main enance cos , is en i onmen ally iendly, and has a wide ange o applica ions. Howe e , i has d awbacks, such as inc easing he sola panel’s empe a u e by 10 deg ees Celsius, esul ing in a 0.5 pe cen dec ease in elec ical e iciency o silicon cells because cooling o he sola panel may be equi ed o imp o ed e iciency. Cooling liquids such as ai o wa e a e used in he sola panel sys em o educe he empe a u e [ 4 – 9 ]. The e a e wo ways ha he pe o mance o a sola panel can be inc eased. Fi s is sola panel cooling, and ano he is a medium o s o ing was e hea . Ai and wa e a e commonly used o cool sola panels as a adi ional cooling me hod. None heless, i has i s own se o i ues and me i s. As a esul o he o egoing encoun e s, Ene gies 2022,15, 4425. h ps://doi.o g/10.3390/en15124425 h ps://www.mdpi.com/jou nal/ene gies Ene gies 2022,15, 4425 2 o 12 many esea che s wo ldwide ha e been using nanoma e ials as a supe io cooling luid o imp o e he mal and elec ical pe o mance. As a esul , o e all pe o mance can be imp o ed. The ollowing a e some examples o success ul s udies conduc ed a ound he wo ld. Choi and Es man [ 10 ] pionee ed nano luids as a coole in PVT sys ems, which spa ked conside able in e es due o hei supe io he mophysical p ope ies examined o he s anda d luids. The solid-liquid syn hesized nanopa icles in a company wi h diame e s ypically anging om 1–100 nm d i ing in wa e [11]. Many expe imen s demons a ed ha wa e nano luid has a signi ican ly la ge hea ans e coe icien occu s han basic luids [ 12 – 14 ]. The en ichmen o hea ans e was done by nano luids in hyb id collec o s, wi h a ew nega i e impac s, such as inc eased p essu e d op in he sys em [ 15 ], a limi ed pe iod o i s s abili y, and a highe cos o nanopa icles. Sa da abadi e al. [ 16 ] expe imen ed wi h wa e as a base luid wi h PVT sys ems and a a ious concen a ions o SiO 2 nano luid. I was concluded ha o e all pe o mance a ained 3.6 o 7.9 pe cen o 1 o 3 w . pe cen . Ghadi i e al. [ 17 ] examined wa e and e o luid wi h a ying composi ions using an indoo PVT sys em. The o e all e iciency was 45 pe cen when compa ed o a hyb id sys em. Sa da abadi e al. [ 18 ] used deionized wa e o dissol e h ee ypes o nanopa icles (AL2O3, TiO2, and ZnO). Al-shamani e al. [ 19 ] expe imen ed wi h a ious nano luids a di e en low a es. Acco ding o he esul s, sic had he highes elec ical pe o mance o abou 13.52 pe cen and he o e all maximum e iciency o 78.24 pe cen . Sol ani e al. [ 20 ] demons a ed an in es iga ional s udy in a hyb id sys em using wa e nano luid. I was disco e ed ha ull enac men and powe gene a ion inc eased by 3.13 pe cen and 52.4 pe cen , espec i ely. The au ho s also e ealed ha SiO 2 imp o ed o al pe o mance and powe gene a ion by 3.29 pe cen and 43.36 pe cen , espec i ely. Al-Waeli e al. [ 21 ] used collec o s o in es iga e h ee ypes o nano luids. Al-Waeli e al. [ 22 ] demons a ed he in luence o Silicon chlo ide/wa e nano luid on hyb id sys ems, which imp o ed elec ical ene gy e iciency o 23.9 pe cen and hea powe e iciency o 99.23 pe cen . I also disco e ed ha i had a supe io o e all pe o mance o app oxima ely 88.9 pe cen when compa ed o a PV sys em. Mohammad Sa da abadi e al. [ 23 ] examined he silica nano luid’s e iciency in a PVT sys em expe imen ally. I concluded wi h a 7.9 pe cen imp o emen in o e all pe o mance and a 24.3 pe cen imp o emen in exe gy. Fo long- e m s abili y, Ag/wa e nano luid was p ocessed by elec ical explosion o wi e [ 24 , 25 ]. The sys em was e alua ed using a he modynamic s udy, speci ically ene gy and exe gy e iciency. This expe imen was ca ied ou using a ious low pa e ns and concen a ions. Muhammad Azam in es iga ed a ma hema ical model o a chemically eac i e Maxwell nano luid o axisymme ic low using he Ca aneo-Ch is o hea lux model and a e ised nano luid model. [ 26 ]. The impac o A henius ac i a ion ene gy and mel ing e en s on chemically eac i e Falkne -Skan low o c oss nano luid ac oss a mo ing wedge wi h iscous dissipa ion and nonlinea adia ion impac s a e s udied using a heo e ical nu- me ical communica ion [ 27 ]. The p ima y goal o his pape is o in es iga e he e ec s o mel ing phenomena and nonlinea chemical eac ions on ansien biocon ec ion low o a su e by nanoliquid wi h gy o ac ic mic oo ganisms and hea sou ce/sink [ 28 ]. Muham- mad Azam [ 29 ] s udied he uns eady bio-con ec ion low o nano luid unde he impac o mic oo ganisms and nonlinea adia ion using ma hema ical modeling and simula ion. The esea ch goal is o demons a e manganese chlo ide as a coolan o imp o e he PVT collec o pe o mance. The manganese chlo ide nano luid has been expe imen ally explo ed o he i s ime o cool and imp o e he pe o mance o a single glazing su ace PVT sys em. The de eloped PVT collec o and PV module we e es ed ou doo s a he Chennai me eo ological s a ion using 0.5 w . pe cen concen a ions o nano luids and pu e wa e as coolan s a 0.5 and 1.0 L pe minu e. The ene ge ic s udy o a hyb id collec o wi h nano luid coolan s was ca ied ou , and compa isons o PV modules and wa e -cooled PVT sys ems we e. I was also disco e ed ha he indings o his inqui y we e equi alen o hose published in pee - e iewed jou nals. Ene gies 2022,15, 4425 3 o 12 2. Expe imen al S udy P ocedu e The indings a e om es s conduc ed in A adi, nea Chennai (The Capi al o Tamil Nadu, Sou he n India). Chennai ci y is loca ed on he he mal equa o and he coas , which p e en s seasonal empe a u e a ia ions om becoming conside able. The a e age ela i e humidi y is 69%, he a e age ambien empe a u e anges om 24.8 ◦ C o 33.1 ◦ C, and he a e age numbe o sunshine hou s is 7.8. The sugges ed app oach was buil , p oduced, and es ed o de e mine he e iciency o nano-PCM and nano luid PVT sys ems, hen compa ed o liquid PVT sys ems and ees anding PV modules. In addi ion, wa e as a coole wi h a ied low a es was es ed in he PVT sys em, while nano-PCM and nano luid wi h a ying concen a ions and low a es we e es ed in he hyb id collec o . The inished sys em is a sel -con ained PV module ha usually wo ks—an expe imen al se up a he speci ic loca ion in Figu e 1. As pe he Indian subcon inen is loca ed in he no he n hemisphe e o he ea h whe e a 13-deg ee inclina ion is measu ed. In his s udy, he e is no a ia ion in inclina ion. Ene gies 2022, 15, x FOR PEER REVIEW 3 o 14 pu e wa e as coolan s a 0.5 and 1.0 L pe minu e. The ene ge ic s udy o a hyb id collec o wi h nano luid coolan s was ca ied ou , and compa isons o PV modules and wa e - cooled PVT sys ems we e. I was also disco e ed ha he indings o his inqui y we e equi alen o hose published in pee - e iewed jou nals. 2. Expe imen al S udy P ocedu e The indings a e om es s conduc ed in A adi, nea Chennai (The Capi al o Tamil Nadu, Sou he n India). Chennai ci y is loca ed on he he mal equa o and he coas , which p e en s seasonal empe a u e a ia ions om becoming conside able. The a e - age ela i e humidi y is 69%, he a e age ambien empe a u e anges om 24.8 °C o 33.1 °C, and he a e age numbe o sunshine hou s is 7.8. The sugges ed app oach was buil , p oduced, and es ed o de e mine he e iciency o nano-PCM and nano luid PVT sys- ems, hen compa ed o liquid PVT sys ems and ees anding PV modules. In addi ion, wa e as a coole wi h a ied low a es was es ed in he PVT sys em, while nano-PCM and nano luid wi h a ying concen a ions and low a es we e es ed in he hyb id col- lec o . The inished sys em is a sel -con ained PV module ha usually wo ks—an expe i- men al se up a he speci ic loca ion in Figu e 1. As pe he Indian subcon inen is loca ed in he no he n hemisphe e o he ea h whe e a 13-deg ee inclina ion is measu ed. In his s udy, he e is no a ia ion in inclina ion. Figu e 1. Expe imen al se up a he speci ic loca ion. A mul i-silicon glass panel wi h 1640 mm × 992 mm × 35 mm was pu chased o con- s uc a Pho o ol aic The mal Collec o . Because o he pla o m’s insula ing e ec , a 0.4 mm coppe shee was used o hea abso p ion on he back o he sola panel. Fu he - mo e, he ex e nal and in e nal diame e s o he coppe ube a e 1.0 cm and 0.8 cm, e- spec i ely, and a e placed o obse e hea behind he sola panel. Table 1 shows he pe - o mance o he sola panel unde no mal es condi ions. The pho o ol aic he mal sys- em was o ien ed 13 deg ees sou h. E e y day, be ween 8 a.m. and 5 p.m., eadings o all wea he condi ions and ou pu powe we e ob ained o i een minu es. A coppe ube connec ed o a sola panel is shown in Figu e 2. This coppe ube is used because o high hea conduc ion om he sola panel o he wa e which is passing h ough he pipe. When placing he coppe pipe, i mus be aken ca e ha he en i e leng h is in con ac wi h he Figu e 1. Expe imen al se up a he speci ic loca ion. A mul i-silicon glass panel wi h 1640 mm × 992 mm × 35 mm was pu chased o cons uc a Pho o ol aic The mal Collec o . Because o he pla o m’s insula ing e ec , a 0.4 mm coppe shee was used o hea abso p ion on he back o he sola panel. Fu - he mo e, he ex e nal and in e nal diame e s o he coppe ube a e 1.0 cm and 0.8 cm, espec i ely, and a e placed o obse e hea behind he sola panel. Table 1shows he pe o mance o he sola panel unde no mal es condi ions. The pho o ol aic he mal sys em was o ien ed 13 deg ees sou h. E e y day, be ween 8 a.m. and 5 p.m., eadings o all wea he condi ions and ou pu powe we e ob ained o i een minu es. A coppe ube connec ed o a sola panel is shown in Figu e 2. This coppe ube is used because o high hea conduc ion om he sola panel o he wa e which is passing h ough he pipe. When placing he coppe pipe, i mus be aken ca e ha he en i e leng h is in con ac wi h he sola panel, and a special a angemen using a clamp was used o make su e ha he pipe is always in con ac wi h he sola panel. To inc ease hea ansmission and educe ma e ial cos s, he nano luid was used in he sola panel sys em. The single-phase me hod explains he hea conduc i i y and p ope ies o nano luid TiO 2 . The basic assump ion o his echnique is he mal equilib ium is main ained o nanopa icles and base luid, causing he suspension o beha e like Ene gies 2022,15, 4425 4 o 12 a egula luid. The luid cha ac e is ics a e hen p esumed o ha e been al e ed as a esul o he in oduc ion o nanopa icles. The essen ial pa o he single-phase me hod unde hese assump ions is de e mining he e ec i e he mo-physical cha ac e is ics o he nano luids. The e o e, he selec ion o compe en d i e s wi h easonable cos s ha may be sold oge he is an essen ial conside a ion. Figu e 3shows he image o SEM o TiO2nanopa icles. Table 1. De ails o he sola panel. Pa ame e Value Uni Pmax 260 Wa s Amps in Pmax 8.42 Amps Vol s in Pmax 30.9 Vol s Cu en in Maximum Load 8.89 Amps Vol age in Maximum Load 37.7 Vol s Weigh 18.2 Kilog am Ene gies 2022, 15, x FOR PEER REVIEW 4 o 14 sola panel, and a special a angemen using a clamp was used o make su e ha he pipe is always in con ac wi h he sola panel. Figu e 2. Pho og aphic iew o he coppe ube along wi h he sola panel. Table 1. De ails o he sola panel. Pa ame e Value Uni Pmax 260 Wa s Amps in Pmax 8.42 Amps Vol s in Pmax 30.9 Vol s Cu en in Maximum Load 8.89 Amps Vol age in Maximum Load 37.7 Vol s Weigh 18.2 Kilog am To inc ease hea ansmission and educe ma e ial cos s, he nano luid was used in he sola panel sys em. The single-phase me hod explains he hea conduc i i y and p op- e ies o nano luid TiO2. The basic assump ion o his echnique is he mal equilib ium is main ained o nanopa icles and base luid, causing he suspension o beha e like a eg- ula luid. The luid cha ac e is ics a e hen p esumed o ha e been al e ed as a esul o he in oduc ion o nanopa icles. The essen ial pa o he single-phase me hod unde hese assump ions is de e mining he e ec i e he mo-physical cha ac e is ics o he nano luids. The e o e, he selec ion o compe en d i e s wi h easonable cos s ha may be sold oge he is an essen ial conside a ion. Figu e 3 shows he image o SEM o TiO2 nanopa icles. Figu e 2. Pho og aphic iew o he coppe ube along wi h he sola panel. Ene gies 2022, 15, x FOR PEER REVIEW 5 o 14 Figu e 3. Pho og aphic iew o he coppe ube along wi h he sola panel. 3. Analy ical Me hodology Elec ical and he mal ene gy analyses we e ca ied ou in his me hodology, which a e de ailed below [30–34]. The go e ning di e en ial equa ion o he beha io o he sys ems a e based on: 1. S eady-s a e ope a ion. 2. The inle mass low a e in o he sola he mal s o age ank is cons an . 3. The adia ion hea ans e is negligible. 4. The dus deposi ion on he sola panel is meage . 3.1. Pe o mance o Elec ical Ene gy The a io o elec ical ene gy is elec ical powe , and he panel ene gy obse a ion and equa ion a e gi en below.  =   (1)  (2) =  (3) 3.2. Pe o mance o The mal Ene gy The e iciency o he mal ene gy is employed o cha ac e ize he pe o mance o a PV/T sys em.  ℎ  =  (4) =   =  (− ) (5)  =  (6) These equa ions a e based on he sola adia ion alling on he pa icula a ea o he sola panel being well de ined in he sola adia ion obse a ions. These obse a ions a e known as . The mass low a e o coolan , hea ca ying capaci y o he coolan di e - ence o inle , and he ou pu o he coolan a e combined, p oducing wha is known as hea ene gy gene a ion . 3.3. Unce ain y Analysis Figu e 3. Pho og aphic iew o he coppe ube along wi h he sola panel. Ene gies 2022,15, 4425 5 o 12 3. Analy ical Me hodology Elec ical and he mal ene gy analyses we e ca ied ou in his me hodology, which a e de ailed below [ 30 – 34 ]. The go e ning di e en ial equa ion o he beha io o he sys ems a e based on: 1. S eady-s a e ope a ion. 2. The inle mass low a e in o he sola he mal s o age ank is cons an . 3. The adia ion hea ans e is negligible. 4. The dus deposi ion on he sola panel is meage . 3.1. Pe o mance o Elec ical Ene gy The a io o elec ical ene gy is elec ical powe , and he panel ene gy obse a ion and equa ion a e gi en below. ηelec =Pmax . Qs (1) Pmpmpmax (2) . Qs=Acol IG(3) 3.2. Pe o mance o The mal Ene gy The e iciency o he mal ene gy is employed o cha ac e ize he pe o mance o a PV/T sys em. η he = . Qu . Qs (4) . Qu=. mCp∆T=. mCp(To−Ti)(5) . m=ρAcolV(6) These equa ions a e based on he sola adia ion alling on he pa icula a ea o he sola panel being well de ined in he sola adia ion obse a ions. These obse a ions a e known as . Qs . The mass low a e o coolan , hea ca ying capaci y o he coolan di e ence o inle , and he ou pu o he coolan a e combined, p oducing wha is known as hea ene gy gene a ion . Qu. 3.3. Unce ain y Analysis The indi idual calib a ion dis o ion pa ame e s o he PVT collec o a e shown in Table 2. Unce ain ies analysis is equi ed o con i m he accu acy o each expe imen al se up. Da a ex ac ion mis akes, example calib a ion p oblems, da a p ocessing e o s, and unique ins umen ambigui ies a e all examples o e o s. The majo i y o he inaccu acies in his s udy we e p oduced by he o e es ima ion o each a iable, such as empe a u e, sola i adia ion, s ess, and luid eloci y. The mos signi ican unce ain y in p edic ing sola collec o e iciency is abou 3.6 pe cen (Table 3). Table 2. Indi idual calib a ion dis o ion pa ame e s o he PVT collec o . Senso Dis o ion Type Ambien ai empe a u e ±0.2 ◦C K- he mocouple Hea pipe empe a u e ±0.2 ◦C K- he mocouple Ro ame e ±2.3% UKL Sola powe me e ±4 W/m2TM-206 Inle & ou le empe a u e ±0.2 ◦C K- he mocouple Da a logge ±3.4% Agilen 34980A Ene gies 2022,15, 4425 6 o 12 Table 3. Pe cen age inc ease o he mal e iciency %. Sl. No Wo king Fluid The mal E iciency (%) A e age A Ex eme Sola Radia ion 1 0.5 LPM 25.76% 35.31% 2 1.0 LPM 29.88% 40.96% 3 0.05% TiO2wi h 0.5 LPM 36.32% 49.79% 4 0.05% TiO2wi h 1.0 LPM 40.70% 55.80% 4. Resul s and Discussion Acco ding o he indings, he empe a u e g adien panels g ew h oughou he day as sun i adia ion inc eased. The pa e n o ai empe a u e and sola adia ion is simila ; howe e , he PV su ace emp/ adia ion ac o o PV panels is subs an ially mo e signi ican han o cooled panels. Fu he mo e, he empe a u e di e en ial be ween he cooling PV panel and he baseline panel d opped; o example, a midday, he di e ence was 12.6 ◦ C, bu a he end o he day, i was only 7.2 ◦ C due o Nano luid obs uc ing he cooling unc ion. This s udy also includes se e al o he pa ame ic es s de ailed below. In Figu e 4, he sola adia ion in ensi y o chosen days was gi en o compa ison as an example o a simila me ological s a e. E e y 15 s, he da a is collec ed and used o u he analysis. The en i onmen al da a, sola in ensi y, and wea he condi ions om he ini ial days we e ga he ed, which a e shown in Figu e 4. F om his g aph, he diu nal a e age incoming sola adia ion dispe sion o e he expe imen pe iod is a whis le shape. I was obse ed du ing he es ha he smalles alues we e 307.18 W/m 2 , eco ded on mo ning 7, and 219 W/m 2 on e ening 5. The daily a e age ai empe a u e ises om 29.36 o 34.23 deg ees Celsius om 9 a.m. o 5:00 p.m. Ene gies 2022, 15, x FOR PEER REVIEW 7 o 14 Figu e 4. A e age expe imen al day o he wea he in o ma ion a a speci ic loca ion. The inciden sola adia ion on chosen days is depic ed in Figu e 5 a a ce ain poin in he expe imen al esea ch in a sample o iden ical me ological si ua ions. Sola adia- ion is an essen ial ac o in boos ing he pe o mance o bo h luids. The sola adia ion and ambien empe a u e a he exac a ea displayed simila pa e ns h oughou he day. Figu e 5. Th ee expe imen al es days o sola adia ion in W/m2. The TiO2 nano luid u ilized had an ideal olume le el o 0.05 pe cen . Figu e 6 demons a es ends in elec ical e iciencies, such as ees anding PV, wo ypes o wa e low a es, and TiO2 nano luid olume concen a ion. The sys em e iciency was inc eased by 67.25 pe cen on a e age du ing he ial day when he op imal concen a ion o he chosen Nano luid was used compa ed o he non-cooled module. The luc ua ion in sola cell e iciency wi h espec o ime and ai mass low a e is demons a ed in Figu e 7. The g aph demons a es ha he inc eased mass low a e in he PVT collec o esul s in lowe cell empe a u e and g ea e cell e iciency. 0 200 400 600 800 1000 1200 7 8 9 10 11 12 13 14 15 16 17 18 Sola Radia ion (W/m2) Time o he day (h s) Exp. Tes Day 1 Exp. Tes Day 2 Figu e 4. A e age expe imen al day o he wea he in o ma ion a a speci ic loca ion. The inciden sola adia ion on chosen days is depic ed in Figu e 5a a ce ain poin in he expe imen al esea ch in a sample o iden ical me ological si ua ions. Sola adia ion is an essen ial ac o in boos ing he pe o mance o bo h luids. The sola adia ion and ambien empe a u e a he exac a ea displayed simila pa e ns h oughou he day. Ene gies 2022,15, 4425 7 o 12 Ene gies 2022, 15, x FOR PEER REVIEW 7 o 14 Figu e 4. A e age expe imen al day o he wea he in o ma ion a a speci ic loca ion. The inciden sola adia ion on chosen days is depic ed in Figu e 5 a a ce ain poin in he expe imen al esea ch in a sample o iden ical me ological si ua ions. Sola adia- ion is an essen ial ac o in boos ing he pe o mance o bo h luids. The sola adia ion and ambien empe a u e a he exac a ea displayed simila pa e ns h oughou he day. Figu e 5. Th ee expe imen al es days o sola adia ion in W/m2. The TiO2 nano luid u ilized had an ideal olume le el o 0.05 pe cen . Figu e 6 demons a es ends in elec ical e iciencies, such as ees anding PV, wo ypes o wa e low a es, and TiO2 nano luid olume concen a ion. The sys em e iciency was inc eased by 67.25 pe cen on a e age du ing he ial day when he op imal concen a ion o he chosen Nano luid was used compa ed o he non-cooled module. The luc ua ion in sola cell e iciency wi h espec o ime and ai mass low a e is demons a ed in Figu e 7. The g aph demons a es ha he inc eased mass low a e in he PVT collec o esul s in lowe cell empe a u e and g ea e cell e iciency. 0 200 400 600 800 1000 1200 7 8 9 10 11 12 13 14 15 16 17 18 Sola Radia ion (W/m2) Time o he day (h s) Exp. Tes Day 1 Exp. Tes Day 2 Figu e 5. Th ee expe imen al es days o sola adia ion in W/m2. The TiO 2 nano luid u ilized had an ideal olume le el o 0.05 pe cen . Figu e 6 demons a es ends in elec ical e iciencies, such as ees anding PV, wo ypes o wa e low a es, and TiO 2 nano luid olume concen a ion. The sys em e iciency was inc eased by 67.25 pe cen on a e age du ing he ial day when he op imal concen a ion o he chosen Nano luid was used compa ed o he non-cooled module. The luc ua ion in sola cell e iciency wi h espec o ime and ai mass low a e is demons a ed in Figu e 7. The g aph demons a es ha he inc eased mass low a e in he PVT collec o esul s in lowe cell empe a u e and g ea e cell e iciency. Ene gies 2022, 15, x FOR PEER REVIEW 8 o 14 Figu e 6. E iciency o PV and PVT modules wi h wo king luids. As illus a ed in Figu e 7, cooling de ices lowe ed he a e age empe a u es o PV and PVT modules, whe he employing il e ed wa e o in oducing nano luid in o he liquid. The empe a u e o he PV and PVT panels inc eased as he sola adia ion le els inc eased du ing he day. E en hough he maximum su ace empe a u e o he modules has ollowed he same ajec o y as he sola adia ion, he empe a u e o PV is signi i- can ly g ea e o PV panels han o cooling panels. The PV panel and he egula panel di e ence in empe a u e dec ease du ing he day. The empe a u e di e ence a midday was 16 °C, and a he end o he day was 15 °C, because he hea s o ed in he Nano luid began o ha e a e e se impac . The a e age empe a u e o he ial day, a ees anding PV module, and he highes nano luid concen a ion wi h a high- olume low a e we e 51.3 °C and 38.8 °C, espec i ely. Figu e 6. E iciency o PV and PVT modules wi h wo king luids. As illus a ed in Figu e 7, cooling de ices lowe ed he a e age empe a u es o PV and PVT modules, whe he employing il e ed wa e o in oducing nano luid in o he liquid. The empe a u e o he PV and PVT panels inc eased as he sola adia ion le els inc eased du ing he day. E en hough he maximum su ace empe a u e o he modules Ene gies 2022,15, 4425 8 o 12 has ollowed he same ajec o y as he sola adia ion, he empe a u e o PV is signi ican ly g ea e o PV panels han o cooling panels. The PV panel and he egula panel di e ence in empe a u e dec ease du ing he day. The empe a u e di e ence a midday was 16 ◦ C, and a he end o he day was 15 ◦ C, because he hea s o ed in he Nano luid began o ha e a e e se impac . The a e age empe a u e o he ial day, a ees anding PV module, and he highes nano luid concen a ion wi h a high- olume low a e we e 51.3 ◦ C and 38.8 ◦C, espec i ely. Ene gies 2022, 15, x FOR PEER REVIEW 9 o 14 Figu e 7. PV and PVT module empe a u e wi h di e en wo king luids. Figu es 8 and 9 depic a ious wo king luids and hei elec ical e iciency and sun adia ion in he mo ning and a e noon. Acco ding o he diag am, when sola adia ion inc eases, elec ical pe o mance dec eases, which is especially impo an du ing he on line and a e midday. Excessi e sunshine has a signi ican nega i e e ec on he elec ical sola panels’ pe o mance. Sola adia ion is an excellen pa ame e o in luenc- ing he elec ical p ope ies o wa e and wa e -nano luid mix u es. Figu e 7. PV and PVT module empe a u e wi h di e en wo king luids. Figu es 8and 9depic a ious wo king luids and hei elec ical e iciency and sun adia ion in he mo ning and a e noon. Acco ding o he diag am, when sola adia ion inc eases, elec ical pe o mance dec eases, which is especially impo an du ing he on - line and a e midday. Excessi e sunshine has a signi ican nega i e e ec on he elec ical sola panels’ pe o mance. Sola adia ion is an excellen pa ame e o in luencing he elec ical p ope ies o wa e and wa e -nano luid mix u es. Figu e 10 depic s he luc ua ion o inpu and ou pu luid empe a u es wi h a ying olume low a es and concen a ions. The inle ai empe a u e linea ly ollowed he ambien ai empe a u e. The a ia ion in ∆ T was caused by he di e en concen a ion and olume low a es o he nano luids. In gene al, lowe a es o wa e and nano luid mixed wi h wa e esul ed in he mos signi ican empe a u e changes, whe eas highe olume low a es esul ed in he smalles . Acco ding o he ollowing g aphic, an 11.8 ◦ C di e ence was achie ed a a wa e low a e o 0.5 LPM a noon. As a esul , a 13.3 ◦ C di e ence was ob ained a 0 LPM on he es ing day’s midday. Fu he mo e, a ound midday on he ial day, a di e ence o 12.5 ◦C was achie ed wi h wa e mixed wi h a nano luid o 0.5 LPM. A e ha , a midday on he ial day, a di e ence o 9.3 TiO 2 manganese oxide. The PVT collec o was es ed a wo di e en olume concen a ions, 0.5 and 1.0 Li e s pe minu e (LPM). The highes he mal e iciency o he sys em was de e mined o be 48.38 pe cen and 54.03 pe cen , espec i ely, a he olumes o 0.5 LPM and 1.0 LPM. The highes elec ical e iciency o he PV/T collec o was de e mined o be 18.32 pe cen and 19.35 pe cen , espec i ely, o 0.5 LPM and 1.0 LPM o olume low a es. The esul s demons a e ha nano luid has mo e excellen he mal conduc i i y han a base luid wi h a li le inc ease in iscosi y and luid densi y. I was achie ed in wa e mixed wi h nano 1.0 LPM. Ene gies 2022,15, 4425 9 o 12 Ene gies 2022, 15, x FOR PEER REVIEW 9 o 14 Figu e 7. PV and PVT module empe a u e wi h di e en wo king luids. Figu es 8 and 9 depic a ious wo king luids and hei elec ical e iciency and sun adia ion in he mo ning and a e noon. Acco ding o he diag am, when sola adia ion inc eases, elec ical pe o mance dec eases, which is especially impo an du ing he on line and a e midday. Excessi e sunshine has a signi ican nega i e e ec on he elec ical sola panels’ pe o mance. Sola adia ion is an excellen pa ame e o in luenc- ing he elec ical p ope ies o wa e and wa e -nano luid mix u es. Figu e 8. Va ious wo king luids and hei elec ical e iciency and sola adia ion du ing he o enoon o he day. Ene gies 2022, 15, x FOR PEER REVIEW 10 o 14 Figu e 8. Va ious wo king luids and hei elec ical e iciency and sola adia ion du ing he o e- noon o he day. Figu e 9. Va ious wo king luids and hei elec ical e iciency and sola adia ion du ing he a e - noon o he day. Figu e 10 depic s he luc ua ion o inpu and ou pu luid empe a u es wi h a ying olume low a es and concen a ions. The inle ai empe a u e linea ly ollowed he am- bien ai empe a u e. The a ia ion in ΔT was caused by he di e en concen a ion and olume low a es o he nano luids. In gene al, lowe a es o wa e and nano luid mixed wi h wa e esul ed in he mos signi ican empe a u e changes, whe eas highe olume low a es esul ed in he smalles . Acco ding o he ollowing g aphic, an 11.8 °C di e - ence was achie ed a a wa e low a e o 0.5 LPM a noon. As a esul , a 13.3 °C di e ence was ob ained a 0 LPM on he es ing day’s midday. Fu he mo e, a ound midday on he ial day, a di e ence o 12.5 °C was achie ed wi h wa e mixed wi h a nano luid o 0.5 LPM. Figu e 9. Va ious wo king luids and hei elec ical e iciency and sola adia ion du ing he a e noon o he day. Figu e 11 depic s a PVT module he mal e iciency wi h a ious wo king luids. Equa ions (4)–(6) a e used o assess mul iple equa ions o ge he hyb id collec o he mal e iciency. I is es ima ed using quan i iable c i e ia such as he empe a u e di e en ial be ween he exi and in ake ai , ai mass low a e, ai -speci ic hea , sola panel a ea, and sola adia ion. When he low a e changes om 0.5 LPM o 1.0 LPM, he he mal