Experimental assessment of two-phase bubble pump for solar water heating Experimental assessment of two-phase bubble pump for solar water heating

Experimental assessment of two-phase bubble pump for solar water heating

  • 期刊名字:中南大学学报(英文版)
  • 文件大小:897kb
  • 论文作者:CHUTNG Han-shik,WOO Ju-sik,SHI
  • 作者单位:Institute of Marine Industry,Department of Mechanical and Precision Engineering,Division of Marine Engineering
  • 更新时间:2020-07-08
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论文简介

J. Cent. South Unlv. (2012) 19: 1590 -1599DOL: 10.1007/s11771-012-1181-4自SringerExperimental assessment of two-phase bubble pump forsolar water heatingCHUNG Han shik', W00 Ju-sik, SHIN Yong-han', KIM Jum-hyo', JEONG Hyo -min'1. Institute of Marine Industry, Department of Mechanical and Precision Engineering,Gycongsang National University, 445 Iapyeong Dong, Tongyeong, Gycongsangnamdo, 650-160, Korea;2. Department of Mechanical and Precision Engineering, Gyeongsang National University,445 Inpyeong Dong, Tongyeong, Gyeongsangnamdo, 650-160, Korea;3. Division ofMarine Engnering, Mokpo National Maritime University, Haeyangdaehang-Ro 91,Mokpo-si, Jollanam-do, 530-729, Korea◎Central South University Press and Springer-Verlag Bertin Heidelberg 2012Abstract: The research goal is to devclop a new solar water beatcr system (SWHS) that uscs a solar bubble pump instead of anelectric pump. The pump is powered by the steam produced from a evacuated tube collector. Therefore, beat could be transferreddownward from the collector to a hot water storage tank. The designed system consists of two sets of beat pipe evacuated tubecollectorse, a solat bubble purp istalld at an upper level and a water storage tank with a heat exchanger at a lower level. Dischargebeads of 1 and 5 m were tested. The bubble pump could operate at the cllector temperature of about 90 -100。C and vapor gagcpressure of 80- 90 kPa. It is found that water circulation within the SWHS depends on the incident solar intensity and systemdischarge head. Experimental investigations are conducted to obtain the system thermal eficiencies from the hourly, daily andlong-term performance tests. The thermal performance of the proposed system is compared with conventional solar water heaters.The resuts show that the proposed systerno achieves system characteristic eiciency of 10% higher than that of the conventionalsystemns using electric pump if taking the consumption of electric power into account. And the fomer is a zero carbon system.Key words: two-pbase bubble pump; solar water heater systcm (SWHS); zero carbonelectrical energy [5-7].1 IntroductionSUMATHY [8] did experimental studies on a solarthermal water pump, which was composed of a 1 m2Nowadays, solar energy is becoming an importantsolar collector and had an overall fficiency of 0.12%-altemnative resource of renewable energy, while0.14% for a discharge head between 6 m and 10 m andconsuming fossil fuel severely leads to the problem of performed 12- -23 cycles/d. A water mass of 15 kg wasglobal warming.fted in one cycle. WONG and SUMATHY [9-10]Solar water heater has been employed around the presented performances of a solar water pump usingworld in most recent years. A solar water heater systemethyl ether as working fluid and a thermodynamic(SWHS) is an example using solar energy. The wateranalysis, together with optimization of the solar thermalcirculations in the SWHS are divided into two methodswater pump. PICKEN et al [11] investigated[1- 2]: a termosyphon method (passive circulation) anddevelopment of a water piston solar powered steama force circulation method (active circulation). Thepump. LIENGJINDATHAWORN et al [12] presentedthermosyphon method [3- 4] uses natural convection 如parametric studies of a pulsating-steam water pump.circulate water between a solar collector and a storageNATTHAPHON and PICHAI [13] proposed solar watertank (ST), whicb is placed higher than the cllector. Thepump SWHS using water as a working fluid. WONG andsecond one is force circulatio system, wbere a water STSUMATHY [14] reviewed more details of solar wateris installed at a lower level and an electric pump is usedpumps.to circulate water betwcen a ST and a solar collector. TheThe goal of this work is to develop a new wateradvantage of this system is that it adds less weight t acirculation svstem bv usine a solar bubble pump, insteadbuilding roof. However, this system does not saveofan中国煤化I ler to decrease theFoundntion tem: Preiet2011-0021376)6 spported by Basic Science Prognm throughfHC N M H Gmdedby the MistyorEducation, Scicnee and Technology of KoreaReceired date: 2011-09- 06; Actepted date: 2011-12-26Corresponding othor: JEONG Hyo-mnin, Tel: +82-10-9548 -J184; Fox: +82- 5-772 9119; Eomail: hmjcong@gmu.c.kxJ. Cent. South Univ. (2012) 19: 1590-15991591system weight on a roof and save electrical energy. Aranalysis of the economy was also performed.2 Experimental setupThe new bubble pump SWHS consits of three mainparts, as shown in Fig. 1.2.)69~Fig.2 Schematic diagram of bubble pump: 1-Expansionchamber; 2- Separator, 3- Condenser; 4 -Spring; 5-Expansionbag; 6-Tube connected to inlet of heat exchanger, 7-Tubeconnected to outlet of heat excbanger; 8 -Tube connected tooutlet of HEC; 9 -Tube connected to inlet of HEC; 10-Valve;I1-Vapor transporter pipeThe pressure inside the bubble pump was measuredFig. 1 Bubble pump solar water heater system: 1- -Bubble pump;by two pressure transducers (4045-A piezoresistive2- -HEC; 3-Heat exchanger; 4- ST; 5-Warm water spplements;pressure sensors) with accuracy of +0.05% connected tothe separator and condenser. Seven sets of T-type6-Water valve; 7-Pipethermocouple were used to measure temperature of the1) A heat pipe evacuated tube solar cllctor (HEC)surrounding air, water, and vapor at the HEC, the bubble(two sets) having a total area of 2.61 m2 and 45°pump, and the ST with accuracy of +0.5 °C. A DAQ32Yokogawa data acquisition device was used to collect theinclination.2) A bubble pump (BP), made of stainlesss steel andtemperature and pressure data. OVAL MK2 CN006-typerubber, baving a height of 1.0 m and a diameter of0.2 m.mass flow meter was installed at the inlet of heatIt includes three main parts: a separator, a condenser andexchanger to measure the mass flow rate in the system.Solar irradiation was measured with photograph ofan expansion chamber. The condenser has four tubesinsolation sensor with accuracy of +0.2%. The device ofwith two connected to the HEC and the other twothis work is shown in Fig. 3.connected to the heat exchanger in the ST. The structureof bubble pump is shown in Fig.2.3 System operation3) A hot water storage tank (ST), which is a plasticbucket baving a volume of 0.2 m' and covered withThe bubble pump must give the desired pumpinsulation material. There is a heat exchanger installeddischarge (mass flow rate of pumped liquid) at the ratedwithinitItisplacedatalowerlevelof1mand5mheat input. The important geometrical parameters, whichunder the solar collector.govern the bubble pump behavior, are the driving head,All equipments were connected to a pipe in whichthe pump lift and the pump tube diameter. The bubblehot water could flow within a closed loop. It waspump operates most efficiently in the slug flow regimeconcluded that the bubble pump belp make a autoand should operate at its maximum liquid flow rate. Ifpumping and circulating SWHS. The experiment wathe liquid flow rate needs to increase or decrease, thentested for discharge heads of 1 m and 5 m. The dischargethe中国煤化工f the pump will behead is the diference between the average levels of HECchose1HCNMHG:s the maximum.and ST. All data were collected at the Department ofpump SWHS wasMechanical and Precision Engineering, Gyeongsangexplained here in detail. The general operation of thisNational University Tongyeong campus, Korea.system can be explained in several periods of working1592J Cent. South Univ. (2012) 19: 1590-1599Temperaturesensor-Pressure sensorPyranometerBubble pumpCollectorRoftopTempeatureI empeature. FlowmeterDatacollectorWater tank(Heat exchanger)Under rooftop常(a)(b)Fig. 3 Photographs of experimental setup (间) and bubble pump (b)fluid (water): heating and pumping, separating andthe ST and transfers heat to warm water in the tank.condensing, heat exchanging, and reheating, as shown inDuring this process, water in the heat exchanger tube canFig. 1 and Fig.2.be pushed by the high pressure in the separator to thecondenser in bubble pump. The water in condenser is3.1 Heating and pumping periodthen supplied to HEC passing through a pipe to beWater as a working fluid is charged into the wholereheated by solar energy.system from the valve in bubble pump. Before heating,HEC, heat exchanger and ST are full of cold water and4 System analysisbubble pump is empty. The system is a close loop afterturming off the charging valve. In this stage, water in theThermal energy stored in the ST can be calculatedHEC is heated by solar energy. The heating periodascontinues until the temperature in the collector is highsornge =jQJdt=mwsCp,w0T;(1)enough to boil the water. The pumping period startswhen enough bubbles are generated. At this time, thewhere Qs is the heat transferred from the heat exchangermixture of vapor bubbles and hot water together move upto water in the ST, dt is time period, mws is the mass ofto the separator of bubble.water in the ST, Cp,w is the water specific heat, and OT, isthe rise in the water temperature in the ST. The daily3.2 Separating and condensing periodsystem thermnal efficiency n is defined as the ratio ofWhen the mixture of bubbles and hot liquid waterdaily thermal energy stored in the ST to the total solararrives at the separator, bubbles break to the upper partirradiation incident on the collector:and the liquid flows to the lower part of the separator.JQ,dr-x100%(2)With the accumulating of vapor in the separator, theA[Irdtconnected expansion bag is blown up and the spring iscompressed. Meanwhile, a portion of vapor is pressedorthrough pipe 18 to the condenser which has a lowertemperature and is condensed to liquid there.η中国煤化工(3)3.3 Heating exchanging reheating periodwherjfYHCNMHGdris the solarHot water in the separator moves downwardirradiance. Hot is the total solar irradiation incident onthrough a connecting pipe to the heat exchanger inside ofthe collector.J. Ccnt. South Univ. (2012) 19: 1590-15991593The daily pump eficiency is given by ..4-7p=NW.-x100%(4).2Hot.0fwhere N is thenumber of water circulating cycles perday, and W is the required hydraulic energy per cycle,0.8-expressed by.6fW=Vpnghwhere V; is the volume of the pumped water per cycle,Pw is the water density, g is he acceleration of gravity,and h is the discharge head of the systcm.The curmulative eficiency of the pump, 7po is-0.24defined as7q=号x100%(6MomentFig. 4 Solar radiation intensity results of one daywhere E is the cumulative hydraulic energy used by the65pump and E. the cumulative solar energy incident on the60collctor area [15-16].。- TWAdditioally, critical solar iradiance for the themali5twater pump is introduced. The critical value is the solar50}energy threshold supplied to the pump so that the pump。45|can start pumping water.s 405 Results and discussion35In order to give the pertinence inspection of theperformance of bubble pump, both short-term test andlong-term test are analyzed. Due to the different workingcondition, this work also gives the comparison results ofsummer and winter. Necessarily, the comparison obubble pump system and electric pump system will alsoFig.5 Temperature results from water storage tank andbe given in this section.covironment5.1 Short-term result and result analysis50FShort-term analysis is specifially detecting a 29 hsStresult from summer, from 2:00 am on 5th April 2007until 7:00 am in the second day. The properties includethe termperature of environment, bubble pump's separatornd water storage tank, because the environmenttemperature influences the performance of system andseparator temperature is the first respond character whenthe solar energy is absorbed. The results are shown inFigs. 4 -9. The pressures of separator and condenser are可checked because they are the critical proprieties ofbubble pump. Also, insolation and mass flow rate aredetected. All the properties are recorded every 10 s. FromFig. 4, it can be seen that insolation starts to increaseslowly from around 4:30 am but sharply increase at中国煤化工about 6:30 am when the sun-rise. The peak value isachieved at around 13:00 and after this it starts toMHCNMH Gdecrease until a sharp decrease when the solar angle is 0°Fig. 6 Temperatures from water storage tank and solar radiationaround 16:30. After the sun-set at around 17:30, theintensity results1594J. Cent. Souh Univ. (2012) 19: 1590-159910S100-70-60-255040Moment3010020ζ80+106040f20L :Fig. 7 Temperature resuts from separator storage tank andenvironmentFlg. 9Temperature from scparator and mass flow rate resutsAlong with the rise of solar radiation intensity, as__sshown in Fig. 5, the water temperature in storage tankincreases from 25 °C to 60 °C. With the decrease of solar-radiation intensity, the water temperature decreasescorrespondingly, but the decline slope in graph dependson the adiabatic condition. The better the adiabaticcondition of storage tank, the smaller the declined slope.100FPeak temperature happens together with the peak solar80radiation intensity. Environment temperature sensor is6located beside the storage tank. It has an approximatevalue with room temperature and city water temperature.Three temperature values which are cavirormcnt三temperature, water storage tank temperature andseparator temperature are compared in Fig. 7. After thetemperaturc in separator becomes steady, water tankFlg. 8 Temperature from separator and solar rdiation intecasitytemperature starts to increase and the peak temperatureresultsof water tank occurs on the top of a steady condition ininsolation is ncarly zero. During the daytime, there areseparator end. The peak value of water tank temperatureseveral low points as a result of the cloud. As thewill increase and delay a spell depending on the adiabaticinsolation increases, electromagnetic energy is absorbedstatus. During daytime, the separator temperature isby solar collector and transforms into the heat energy ofbigher than room environment temperature and waterwater. This firstly increascs the temperature of scparator,tank temperature, but at night it is about 5 °C lower sincewhich can be seen from Fig. 8, and the temperaturethe separator is outside.increases from 20 °C to 100。C within 1 h.Figures 10, 11 and 12 indicate the pressure changeDuring this time, an over flow resulted from theduring oDe day. The pressure in the bubble pump atvolume increase of working fluid first happens. Thisseparator and condenser part is shown in Fig. 10. Bothspillage brings the initial circulation. As the continuallyseparator and condenser pressures are waving in a smallabsorbed energy, the temperature achieves boilingdomain of81 99 kPa and 74- 88 kPa, respectively,condition, then a higher frequency overflow in separator中国煤化工gy is absorbed inoccurs, and the circulation tends to be stable. This statecollet二when the bilingsustains around 5 h. During this period, temperature instarts.TYHCNMHGingfuidstartst0separator is constant below 100 。C but with smallcirculate and the expansibility inside bubble pump isfluctuation, as shown in Fig.9.abated by the drawing back cold water from storage tank.J. Cent. South Univ. (2012) 19: 1590-159915951.020.98-°二p:0.940.90--20.86-0.82Moment0.780.120.1it0.74m0.08-0.07-0.06LFig. 10 Pressure results from scparator and condenser of bubblepump (p. is atmospheric pressure, 101 325 Pa)0.12F0.11.Fig. 12 Pressure dfference and mass flow rate results。0.10S 0.09-every single fluctuation represents one time circulation,the rebound in fluctuate is resulted from the energy input0.06by sun and after a water drawback it reduces again. Theappearance of pressure difference is different frorm量曼morming to aftermnoon. The value also flucuates but witha mean value decreasing. In every single fluctuate, thepressure difference rebounds to relatively lower levelwith a decreasing energy input which is enough forTh厂boiling but not enough to achieve the last status since thesolar radiation intensity reduces.These phenomena sustain until the circulation stops-15and another rebound of pressure difference occurs sincethere is still a solar energy input. The temperature still喜襄increases at a low level in separator. After the energyFig. 11 Solar radiation intensity and pressure difference resultsinput is zero, pressure difference keeps reboundinglentamente uotil the water tcmperatures in collector andFromthis time, the pumpingaction intermittentlybubble pump are equal. Pressure difference only dependshappens steadily. At around 13:00, there is a rock bottomon the location difference of them, mainly the structureof pressure, which is resulted from the cloudy reduce ofof bubble pump and the initial system setup.solar radiation intensity. On account of lower energyAnyhow, the pressure difference together with theinput, water temperature in collector decreases, and sincepotential energy difference provides the power toa sealed loop for the medium, the pressure decreases atcirculate the water in this close loop, and performs thethis time accordingly. There is no larger fluctuant at night.heat transfer between collector at a high level and heatComparing the waving domain with separator andexchanger locates lower without any force from electriccondenser, pressure difference of then has a relativelydevice. The intention of applied bubble pump in solarsmaller range of6 -11 kPa, as shown in Fig. 12.indirect active hot water systemn is fulflld.This parameter is directly related with the solarMass flow rate, as an inspect parameter of workingradiation intensity, as shown in Fig. 11 and Fig. 12. Itmedi中国煤化inFigs. 12-14.Theinspects a whole day process of circulation in the closevaquite fluctuating.loop. When the solar radiation intensity increases in theEverMYHCNMHGblepumpandsolarmorning, pressure difference fluctuates between twoheat exchanger brings a bubble in the conduit betweenparallel values around 8 and 95 kPa. During this time,them and induces a small negative value, but it is helpful1596J. Cent. South Univ. (2012) 19: 1590-1599shows the energy transfer efficiency..2The temperature difference indicates the energyabsorbency of the system, as shown in Fig. 15. Every1.0vertical line between two temperature lines represents asaved energy at that time. Before the peak point, the0.84length of linc increases along the time and decrease after0.6-the peak, and the decreasing rate depends on theAverageadiabatic condition. Under an idcal adiabatic state, tbe勇0.4peak temperature will be high and will delay until the.2-mass flow rate equals zero. However, it should be awarethat the circulation stops earlier, then the vertical linebetween two temperatures ftom Fig.15 equals zero, andcertainly will reflect an energy lose. Moreover, this isrestricted by the inherent property of bubble pumpsystem and it is avoided less. Nevertheless, comparedMomentwith the wbole day's condition, this amount is limited,Fig. 13 Mean value of mass flow rateand with a good heat preservation instrument, thislimited value can still be reduced. This short-term resultdescribes one-day-running detail and the similarcirculation happens on other days with similar intradayweather.60-25二名ssh35-3025- 1.TEITFig. 14 Solar radiation intensity and mass flow resultsFig 15 Temperature from storage tank and environmentto the entire beat transfer because the convertion of flowdirection provides a second chance for the heat exchange.5.2 Long-term result and analysis of systemThe average value of flow rate should be calculated withSince the winter running performance in the testingthe absolute value from experiment and it is aboutarea is concerned more than other season, the long-term).55 kg/min, as shown in Fig. 13. When the solaranalysis will be based on the experiment results fromradiation intensity increases, the boiling happens morewinter. Figure 16 shows one-month radiation intensityfrequently and it results in the more frequent circulationresults. The average value is about 0.4 kW/m2 at daytime.of water, which indicates the increase of mass flow rate.But from Fig. 16, it can be seen that the storage tankAficr comparing Fig. 12 with Fig. 13, the responsetemperature can achieve 50 °C if the bubble pump isgradation of every parameter should be noticed. After therunning well. This proves the ability of bubble pumpincrease of solar radiation intensity, firstly thesolar hot water system applied in experimental location.temperature of separator increases and the pressureFrom Fig. 16, it can be concluded that the separatorincreases at the meantime. When the temperature irtempe中国煤化化工。solar radiationseparator arrives a required level, the circulation startsintensFm another factor,and the mass flow ratc displays a non-zero result. At last,whichCNMHGYHthe temperature of water tank starts to increase. EachNevertheless, it should be noticed that from Fig. 16reaction occurs at different moments and the tirme slotand Fig. 17, when outdoor temperature is below zero,J. Cent. South Univ. (2012) 19: 1590-15991597connecting tube between heat exchanger and bubble|(@)pump is frozen..94This detail can be found from Fig. 18. At this time,pressure sensor shows an over scale value of -3.337.8because the circulation is choked by the frozen ice insideof tube. The temperature in separator is very low, andsince the heat exchanger, solar collector together with.6bubble pump compose a close loop, the pressure willdecline together with temperature. When it is lower thanthe minimum scale, a minus error value will display.1203+1002F.30Date60 g受of030-Frozen40F-20ofFig. 18 Magnify of pressure over shoot detail: 1-Separaterpressure; 2- Condensor pressure; 3-Inlet temperature oheatexchanger; 4 -Zero Celsius lineFig. 16 Contrast of solar radiation intensity and separatorSurveying the whole winter results, it can betemperature: (@) Radiation intensit; (6) Separator temperatureconcluded that both the temperature and solar radiationintensity influence the performance of bubble pump.Compared with summer, the influence from outdoor10temperature in winter takes more account. However, this80influence can be reduced by the improved heatJ⊥山preservation method. And since the lowest outdoortemperature is only around -2 。C and rarely happens, it40、s absolutely can be redeemed by a good heatpreservation measure.205.3 Comparison of summer and winter running4condition高享亭享空亨京-20Bubble pump solar water heater works based on thesun. Naturally, the season difference of processing exists.The figures show that in summer the solar radiationintensity is higher than that in autumn and winter.Fig. 17 Pressure fluctuation fr long term experiment in winter:panedis higher. In1- Seperater pressure; 2 Condensor pressure; 3- -Inletsumn中国煤化工mn arive 80 °C, buttemperature ofbeatexchanger, 4 Zero Celsius linedurinCN MH Gumn is better thanwinter, au uIc uugucst tcuyclauwc is around 60 °C.the solar radiation intensity is still normal, and there is noSurely, the influence of surrounding temperature sbouldcirculation in the close loop because the water innot be neglected.1598J. Cent. South Univ. (2012) 19: 1590-15995.4 Comparison of bubble pump system and electricelectric pump. No matter a bubble pump system or anpump systemelctric pump system, the final determination is energyThe experiment result from bubble pump solar hotsource of suD. The control panel in an electric pump canwater system is compared with an electric system result.be replaced by an insolation meter in theory in anyThe comparison is based on semi- experimeat andmeans, but the differeat thing is that there is a delay insemi-calculation. The results are not meticulous but havethe temperature increase from insolation, and thelarge significance.temperature difference resulted from bubble pumpThe electric pump system has the same componentsystem has a small difference because sorce absorbedwith bubble pump system besides an electric pump andenergy is used to circulate working fluid. So, bere twocontrol panel. Control panel powered by electricity hasitems are used together to simulate electric pump, astwo temperature sensors located on the outlet and inlet ofshown in Fig. 19.beat exchanger. If temperature of inlet is higher than thatBut since the performance of bubble pump is not allof outlet, then the electric pump runs. If not, the pumpwell on the whole testing time, the simulation based onstops.solar radiation is more accurate.The research imposes two vahues, solar radiationThe capacity of electric pump for domestic hotinteasity and temperature difference between inlet andwater is usually 600- 100 w, with similar collector size,outlet of beat exchanger, to simulate the processing ofand in the same working duration with bubble pump,100(a)、50506亭可TTTTTTTTTTTDate(6)5亭.s-(向中国煤化工资i1HCNMH(Flg 19 Calculating result with solar nadiation intensity and temperature: (@), (6) Temperature; (C), (d) Solar ndiation intensityJ Cent. South Univ. (2012) 19: 1590- 15991599electric pump needs to work for around 80 90 h in 22 d.pasive water heating systerms based on annual operation [小SolEnergy, 2007, 81 207-215.It requires about 480- -900 kWh electric power. If using[2] KALOGIROU s A. Long 1erm performance prediction of fomcedbubble pump system, this energy is from solar and nociculation solar domestic watr heating systcos using anificialextra energy is required, as listed in Table 1.neural networks [0 Applied Energy, 2000, 66: 63-74.3] JOSHI s V. BOKIL R s, NAYAK J K. Tast standards forTable 1 Efficiency analysis of bubble pump solar water heatingtbernosypo-ype solar domestit hot walter syuem: Review andexperimental evaluation小Sol Enengy, 2005, 78: 781- -798.system[4] BELESSIOTIS, MATHIOULAKIS,BELESSIOTIS V,ParameterValueMATHIOULAKIS E. Analytical approach of termosypboa solarWater tank temperature/C25-50domestic bot walcr system performance阴Solar Energy, 2002 .Water tank size/m'0.2307-315.[5]SUMATHY K, VENKATESH A, SRIRAMULU V. The importanceSolar radiation intensity/(kWm了1.75of the condenser in a solar water pump []. Eoegy Cooversion andSolar collector area/m23Management, 1995: 1167- 173.[问] SUMATHY K, VENKATESH A SRIRAMULU V. A solur tbemalWorking time/min00water pump凹. Aplied Energy, 1996: 235-243.[7] SUMATHY K, VENKATESH A SRIRAMULU V. Hea-transfer6 Conclusionssnulysis of a fat.plue cleor in 2 solar tberaul pumop办Eacrgy,1994: 983 9911) The performance of the bubble pump is tightly[8] SUMATHY K. Experimental stodies on a solar thermal water pumpn] Appl Therm Eag, 1999, 19: 449 459.associated with the weather including solar radiation[9] WONG Y W, SUMATHY K. Performance of solur water pump withintensity and sorrounding temperature. The flow rate isebhy)-tber as working fuid [D] Rmnew Enargy. 2001, 22: 389- 394.fluctuant compared with the reference. The mass flow[WONG Y w, SUMATHY K Thrrmodynamic alysis and,rate and pressure difference inside the bubble pumpopimizatio of solar thermal water pump [1 Appl Therm Eng, 2001,21:613- 627.which serves as circulation head of the system are1] PICKEN D ), SEARE K D R GOTO P Desien and developmpent ofunattached to solar radiation intensity.a water piston solar powered stan pumnp 小Sol Energy, 1997,2) Long-term result shows that bubble purmp can be61(3): 219-227.applied to indirect active solar water heating system to[2] LIENGINDATHAWORN s, KIRTIKARA K NAMPRAKAI P.replace the electric pump in the abovc-Zero zoDC. If theKIATSIRIROAT T. Parametuic studis of a palsaing-steam watcrpump [0. Ambient Energy, 2002, 23();37 46.temperature is below zero, enbanced incubation 0[13] NATAPHON R PICHAI N, NARIS P. Experincatal studies ofachanged working fluid is necessary.new solur water beater system using a solur watcar pump凹Encrgy3) The involvement of bubble pump extends the2008. 33: 639 646.application scope of solar water heater. Bubble pump can[14] WONG Y W, SUMATHY K. Solar thermal water pumping sytns:be applied to indirect (close loop) active solar waterA revicw阴Ranew Sustain Energy Rey, 1999, 3(23)2 185 -217.[15] NORTON B. PROBERT S D. Recent advances in circulation solarbeating system instead of the electric pump.eagy water beater desig {m Appl Enengy, 1983. 151);15- 42.[16] ZERROUKI A, BOUMEDIEN A, BOUHADEP K The nahuralReferencescirculation solar water heater model with linear temperatoredistribution []. Rencwable Energy, 2002.26(4): 549- 559.[1] LEE D w, SHARMA A. Thermal prfomancs of tbe active saod(Edlted by HE Yae-bim)中国煤化工MHCNMHG

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