Solar and Wind Assessment in Thailand

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Meteorolcgtal Department Ministry of Communications

SOLAR AND WIND ENERGYRESOURCE ASSESSMENT

FOR THAILAND

Submitted to the National Energy Administration Ministry of Science,Technology and Energy

Under theRenewable Nonconventional Energy ProjectRoyal Thai GovernmentU.S. Agency for International Development


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Transferringceremony of theSolar/WindMeasuringandCalibration equipment fromUSAIDto theMeteorological Department, December 16, 1982.


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ACKNOWLEDGEMENTS

Acknowledgements aremadeto anumber ofpeoplewho, by discussion, contribution, adviceor assistanceto theSolar and WindResource Assessment,helpedtocomplete thework. Appreciationsar-'extended to Dr. Boonsorn Boom~sukha, DirectorGeneral of thel4eteorologica. Department, formanyhelpfulsuggestions, Mr. DunyaponBisonyabut andMr.Dusadee Sukawat, co-leader, fortheir discussions and supports, Mr. Suparerk Tansriratanawong, Chiefof Maintenance andCalibration Sub-Division,andhis staff, for thecalibrationand maintenanceof theinstruments, andpersonnelin theFinancial Sub-Division, fortheirassistancein preparingfinancial documents. Acknowledgements are made toMr.RoderickF. MacDonald,Ex-Director,Mr. JohnW.Neave, Directorand Mr. Mintara Silawatshananai,Engineer/.Project Officer,of theUnited StatesAgency for International Development (USAID), for their adviceandassistance. Mr. PrapathPremmani, Secretary General,Mr.Tammachart Sirivadhanakul, Deputy SecretaryGeneral,Mr. Sompongse Chantavorapap,ProjectManager flum theNational EnergyAdministration (NEA), Dr.MauriceL.Albertson, Senior Technical ProjectManagementExpert andMs.LanaLarsen,Editor, fromthe Officeof ProjectManagement Support, a--a also acknowledgedfor their advice. Acknowledgements are alsomade toDr. MichaelGarstang, consultant of the component fordevelopingthe planfor the assessment, Dr. R.H.B.Exell, localconsultant for assistinginthe implementationof procedures anddoing analysis of newdata, Associate Professor Banterg Suwantrakul andhis colleaguesfor analysis ofexisting data. Gratitudeisexpressed to the Departmentof Technical and Economic Cooperation (DTEC)forarranging narticipant training,and to USAID forits support and financialassistancewithoutwhichthisworkwould nothavebeencompleted.

Ms. Soranee Sangmit Component Leader


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CONTENTSPage

EXECUTIVESUMMARY ................. . ........ 11 15ist ofTables .......................................................Listof Figures ....................................................... 17 CHAPTER1 INTRODUCTION

A. Historical Background ................................. 21 B. OverallObjectives.....................................21 C. Significance .......................................... 22 D. Scope ................................................. 22

CHAPTER 2 EXISTINGDATABASE A. Solar Energy .......................................... 25 B. WindEnergy ........................................... 30

CHAPTER 3 REVIEWOFTHELITERATURE A. Foreign ConsultantPlanning ........................... 35 B. Prev-ousStudies inThailand .......................... 35

CHAPTER 4 DESIGOj OFTHE STUDY A. Organization ..........................................43 B. Additional Measurements ...............................44 C. MeasurementMethods ...................................52 D. Maintenance andCalibrationof Instruments ............ 56 E. Data Processing ....................................... 59 F. Existing Data.........................................65 G. NewData .............................................. 68 H. Training .............................................. 68 I. Consultatiun .......................................... 70 J. CooperationwithotherAgencies ....................... 70 K. PersonnelTimeCommitments ............................ 71 L. Budget ................................................72

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CHAPTER 5

CHAPTER6

CHAPTER7CHAPTER 8ANNEXES

CONTENTS (continued)Page

TECHNIQUES ANDPROCEDURES 75A. Organization ...........................................76Additional IMeasurements ................................B. 77C. MeasurementMethods ....................................

Instruments ............. 80D. Maintenance and Calibration of85E. Data Processing ........................................85F. Training ...............................................86G. Budget ..................................................

ANALYSISOFRESULTS 89A. Existing Data.......................................... 90B. NewData ............................................... 93CONCLUSIONS ......................................97RECOMMENDATIONS ..................................

I. METandNEAStationLocations........................... 99107II. Mapsof Stations ........................................

III. SynopticClassificntion ..................................111 117IV. ForeignConsultant ......................................

V. Local Consultant......................................... 123 Recommendationsof Evaluation Team...................... 131VI.TrainingCourse inSolar andWindResources,VII. 1983- January 6,1984 ..................... 135December 12,RegionalCalibration .................................... 145VIII.

151Procurement .............................................157

IX.X. TimeSchedule ...........................................

164XI. Activities ............................................... 174 REFERENCES ..................................................

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EXECUTIVE SUMMARY

TheSolar/WindResourceAssessmentComponentwasone of the components inthe USAID-ThaiRenewableNonconventionalEnergyProject, USAIDProject No. 493-0304. Theobjective of the solarandwind resourcesassessment was to specifyhowthe solar andwind energypotentialof Thailandcan be reliablydeterminedand subsequentlymonitored. The Meteorological Departmentwas theagency responsible for this component. Theproject started in 1981 and willbe completed in 1984. After the proje:t has beencompleted, itsactivitieswillbecontinuedby theMeteorological Departmenton aroutinebasis.

The assessment of solarand windenergyfor Thailandconsisted of:

EstablishingaCenter for Solar RadiationandWind Calibration;and * Evaluationof data. In orderto do theassessment,additional solarradiation andwind

measurementswererequired. For this reason,6solarradiationmonitoring stations and 10 windmonitoringstationswere setup. At thesestations, observed solarradiationandwindare transformed into electricalsignals and fed intodataloggers forreal-timedta processing. Theprocessed datawerethenautomaticallyrecordedor.magnetic tapecassettesfor further analysis.

Evaluation of data was divided into existingdata andnewdata. Evaluationof existingdata by KingMongkut's Instituteof Technology, Thonburi Campus; and evaluationof newdata (1983) by DK. R.H.B. Exell from theAsian Institute of Technology show that, except at some coastal sites, solarenergy hashighervalue than windenergy. Adetqiled analysisof existing andnewdata has beenpublished separately from this report as "Solar andWind Energy Potential Assessment of lhailand", (Suwantrakul et al., 1984) and "Solar andWind EnergyDataof Thailand1983", (Exell and Sukawat, 1984).

Besidessetting upnewmeasurement,collectionanddata evaluation processes, the projectcalibrated the existing solarradiationand wind instruments ofmanyagencies. Theseeffortsformasolid base forfurther dataanalysis in the future.

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CONCLUSIONS

1. Theactivitiesof the solar/wind assessmentcomponent were centeredat the MeteorologicalResearchSub-Division, St-'4sand -ResearchDivision,Meteorological Department. 2. TheCenter forSolar RadiationandWind Calibratio,was established at theCalibration Sub-Division, InstrumentalDivision,

BangNa Meteorological Office. 3. Additionalmeasurements are done at 6stations forsolar radiation, and 10 stations forwind. Alladditionalmeasurements are automatically recordedby dataloggers. 4. Thereisaproblemwithcontinuity of datarecordedby the datalogger due to instrumentmalfunction. 5. Calibrationof solarandwind instrumentsfaced problems becauseof timelimitations, humanresources and spare instruments. 6. Nationalstandardsolar radiationinstrumentswerecalibrated

at WMORegionalCenters inAustralia. 7. Maintenance of solarinstruments,wind instruments, and adataloggerishinderedby theproblemof unavailable sparepartswithin

Thailand. 8. Analysis ofexistingdataby KMIT andnewdata by Dr. Exellof AITwas completed andpublished as separatetechnical reports. 9. In-country trainingwasmostlycompletedas itwas planned, but overseastrainingwas cancelled due to the delaysat DTEC.

10. Foreignand localconsultants provedvery useful.

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RECOMMENDATIONS

1. Additionalmeasurementsof solar radiationandwind shouldbetaken (bothin spaceand time) toyieldmorerepresentativedata for furtherresearch. 2. The dataloggerusedin automatic datarecordingshouldbemodified formore durability. Spareparts shouldbe sufficientlysupplied to ensurecontinuity ofrecordeddata. 3. Qualified researchers and operators shouldbe assignedto carry on projectactivities,andshouldbe trainedto be able todo thejobwithout theassistance ofaconsultant.

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LIST OF TABLES

Table Title Page4.1 Classification of Pyranometers ................................. 47 4.2 Specifications of the EppleyPrecisionSpectralPyranometer .... 48 4.3 PersonnelTime ;o- ,l Its ...................................... 71I.1 Cloud4,,Css Stationsb.,iv .................................101 1.2 Sunsttinp Di:ratj,,,i ( ervationStations .......................... 102 3 Measurein.ntF s at HydrologicalStationbyNEA ................ 103

1. Surface'in,' ,easurementsMadeat MeteorologicalStations ....... 104 X.I Time )cf, ,ule ................................................... J58

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LIST OF FIGURES

Figure Title PageII.1 Map ShowingSolarRadiationStations of theProject ........... 109 11.2 Map ShowingWindStationsof theProject.......................110 III.1 S.W.MonsoonSynoptic Model (2,000 ftstreamlines)............. 113 111.2 Exampleof streamlines overThailand at 2,000ftwith

avortextrainlying to the northof Thailand.................. 114 111.3 N.W.MonsoonSynopticModel (5,000ft streamlines)............. 115 111.4 Exampleof streamlines overThailand at 5,000ftwith

anticyclonic systemdominatingflow ........................... 116 XI.1 TransferringCeremony ofSolar/Wind Project.................... 166 XI.2 Establishingthe CenterforSolarRadiation andWind

Calibration....................................................166 XI.3 WindTunnel .................................................... 167 XIo4 EppleyPrecision SpectralPyranometerwithShadowBand......... 167 XI.5 EppleyNormal IncidencePyrheliometerwithSolarTracking...... 168 XI.6 Windmonitoringsystemat Rayong............................... 168 XI.7 TheCalibrationCenter......................................... 169 XIo8 Installationof BlackandWhitePyranometer atBanLaMai,

KoSamui.......................................................169 XI.9 Installationof Windsensors................................... 170 XI.10 Pyranometerfor global solarradiation atHatYai.............. 170 XI.ll Windmonitoring systematKhuanPhromThiap,Phuket............ 171 XI.12 Pyranometerand dataloggerat theCenter for Solar

RadiationandWindCalibration................................. 171 XI.13 Dataprocessingsystemused in theproject..................... 172 XI.14 Calibrationof NationalStandardRadiometerat WMO

RegionalRadiationCenter,Australia........................... 172 XI.15 Staff of Solar/WindResourceAssessmentComponent.............. 173

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Chapter 1

Introduction


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INTRODUCTIONTheobjectiveof thisreportisto givegeneralinformationabout the Solar andWind EnergyAssessment Componentof the USAID-ThaiRenewable Nonconventional Energy.Project. Thisreport isnot intended tobetechnical-note,however,some technicaldetailcan befound. Inthis chapterthe historicalbackground, objectives, significanceand scopeofthisstudy aredescribed.

A. HISTORICALBACKGROUND

Duringthe past fewyears theeconomicdevelopmentof Thailandhas facedavariety ofproblems,partlybecauseof therapidlyincreasing pricesand thehighdemandforpetroleum. The governmentisawareof this situation, and thereforethe ProjectforAlternative EnergySources was includedin theFifthNationalEconomicandSocialDevelopment Plan. Theobjective ofthe Projectis to increasetheself-reliance of the country'senergysupply. The Renewable Nonconventional EnergyProject wasacooperativeprojectinvolvingThailandand the UnitedStates of Americaas aconsequenceof the United StatesVice-President'svisit toThailandinMay, 1978. The projectcoversvarious fieldsof technologyandconsistsof fourteencomponents, includingBiomass Energy, GeothermalEnergy,and SolarandWind EnergyAssessment. TheNationalEnergy Administration coordinates and supervises theentireProject. TheMeteorological Department of Thailand (MET)isthe agencyreponsible forthe Solar and WindEnergyAssessment component,athreeyearprojectplannedto last from1981 to 1984. After theproject is completed, che MeteorologicalDepartmentwillcontinue itsactivityon aroutinebasis.

B. OVERALLOBJECTIVE

Theobjective of the SolarandWindResourceAssessment is to specifyhowthe solarandwindenergypotentialof Thailandcanbereliably determinedand subsequentlymonitored. Assessmentconsistsof:

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Establishinga"Centerfor Solar RadiationandWind Calibration"for continualmeasurementandcalibrationof radiationandwindinstruments includingmaintenanceof theinstruments; and

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Evaluationof relevant meteorologicaldatato generatea useful setof numericalvalues forsolar andwindenergy whichwill serveas aframeof referencefor calculations of potentialenergyusingthe engineeringspecifications

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ofthe various conversion systems.

C. SIGNIFICANCE

AsThailand isatropical countrywithhighorderradiationand moderatewind, solar andwindenergy seem tobe attractive sourcesof renewableenergy. The assessmentof solarandwindenergy tobe investigated inthisproject was toprovide assistancein evaluating thepotential for solar andwindenergy. Theassessmentwas considered to be themostimportant step tobe takenbeforesystematic harvestingof bothtypesof energy couldbe done. The assessmentwas to provide the foundationfor sound technical, economicand socialdecisions.

D. SCOPE

Thestudywas conductedto determinethe atmosphericconstraints of solar andwindenergy in Thailand. Thefocus of thestudy wason defining thespecialand temporal characteristics of solarand windenergy resources and to provideameansto assess theiravailability andreliabJlityinboth regionaland localterms.

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Chapter 2

Existing Data Base


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EXISTING DATA BASE

Beforedoingthe assessment for solar andwindenergy,daterminationof existingdatashouldbemade. Thiswillbe veryuseful for theplanningofadditionalmeasurements and analysisof data. Thischapterreviews the relatedexistingdataforassessment of solar andwindenergyforThailand.

A. SOLARENERGY Existingdatarelatedto assessment of solarenergyaremostlycollectedbytheMeteorological Department (MET)andtheNationalEnergyAdministration (N1A).

MeasurementsMadeby the MeteorologicalDepartment Anexcellentnetworkof 66 first-classmeteorological stationshasexistedinThailandfor the past25 years. Detailedsynopticanalysisiscarriedout at the surfaceand atvarious levelsin the atmospherefour timesperdayat the forecastcenterin Bangkok. Someof thesedatawereused in thestudydescribed inChapter 3. Additionalanalysesusingthe followingexistingdatasets are proposed, (Gartang, 1981). Cloud cover observationsSixty-six stations (seeAnnex I,Table I.1) recordcloud amountsineighths (octa's)of skycoveredat 0700, 1000, 1300, 1600and 1900 localstandard time (LST). The followingdataare recordedat each observation: * Direction ofmotion of the clouds; " Amountof lowcloud; * Height of base.oflowcloud; * Amount ofmiddle cloud; * Amountof highcloud; and " Total amount of skycovered.

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Forty-three of these stationshavebeenircontinuous operationfor 25 years. Theobserving locationsvaryfromopenrural or coartline locationstourbancenters.

Thesedatarepresent the basis fordetailedanalysis of: " Cloudcoverdistributions in space asafunctionof time and

as afunctionofmeteorologicalstate; * Distinctionsin amountof skycoverbydifferent typesof clouds. Inparticular,adistinction canbemadebetween

low,middleand highcloud. * Estimatesof the numberof hours of sunshinebasedupon the

cloudiness record. Theseestimatescanbe determined for: - timeof day, - timeof year (inincrements of tensof days

tomorethanmonths), - seasons;

* Estimatesof the amountof global radiationavailable for similarbreakdowns as above;

* Frequencydistributions of cloudydaysby incrementsofcloudiness. Onceagainadistinction canbemadebetweencloudtypes.

" Consecutive hoursof cloudiness and consecutivedaysof cloudiness above or belowcertain thresholdsof cloudiness. Distinctioncanbemadebetween the typesof clouds.

Tabulationsand spatialdistributions (maps)of cloudiness and quantities derivedfrom the cloud recordcanbe compiled to aidin theassessmentof theavailablesolar energy. Inparticular, the cloudrecordwill providedetailedtime and spaceinformationon the inter- and intra-diurnaldistributionof solarradiation.

Sunshine observationsTwenty-two sunshinerecorders (Campbell-Stockes), listedinTable1.2

(seeAnnex I) havebeenin operationfromIyear (3stations) tomore than20 years (15 stations). Theobservationshavebeencompiledby the hourand fraction of the hour,by theday, andbythemonth. Thestations arerepresentativeof urban,rural,mountainous,and coastallocations.

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Thesedatarepresentabasisfordetailedanalysisof: 0 Thenumberof hours of sunshineover thecountryasafunction

oftimeand as afunctionofmeteorological state;0 Frequencydistributions ofhours of sunshineby increments

of one hour;* Numberofconsecutive hoursof sunshineandnumberofconsecutivedayswithsunshineabove certain thresholds;0 Interdiurnaldistributions of sunshineasafunctionof

location,timeof yearandmeteorologicalstate; and* Estimates ofthe amountof globalradiationavailableateach locationforeachtime interval. As above, theseestimates canbemade as afunctionof location, timeof

day, timeof year, andmeteorological state. Tabulationsand spatialdistributions (maps)of thenumberof hours with sunshineand the globalradiation derivedfrom the sunshinerecord are compiledto aid intheassessment of the availablesolarenergy.

As forcloudiness, therecordof numberof hourswith sunshineprovides detailed timeand spaceinformation on theinter- andintra-diurnal distribution of solarradiation.

Observationsof thenumberof hourswith sunshinearecombinedwith the estimates of thisquantityfromcloudamounts. Cloud amountsare recordedat all 22sunshine recorderstations. Thus itispossible to carryout adetailedanalysisofthe estimatesofnumber ofhourswith sunshinebasedupon the cloud recordand,fromthis analysis,improve theestimateof numberofhours of sunshine. Theimprovement of the estimateislikelyto be achievedby distinguishingbetweenthe types of clouds and cloudamountsratherthanby simplyusingthetotalsky cover.

Atmospheric visibilityEstimatesofhorizontalvisibility (km)areavailableat thestations makingcloud observationsat thesame timesand for the sameperiodas the cloudobservations. Correlations canbe establishedbetweenhorizontalatmospheric visibility and transmissivityof the solar beamthroughthe atmosphere at locations wherebothvisibilityandsolarradiationmeasurements exist. Ameasureof the turbidityoftheatmospherecan thereforebe estimated at allof the locations wherevisibilitymeasurementsaremade. This determination isparticularly important in choosingalocationtomake

directsolar beammeasurementsandforthe installationof acalibration facility. Exelland Saricali (1976) t'-- that Bangkokexhibitsrelatively highvaluesof turbiditywhile, at otherlocations (ChiangMai), turbidity hasaseasonalvariation. Atmosphericvisibility measurements shouldbe takento extendtheseobservationsover otherparts of Thailand.

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Sun8hine'observations,Sixteensunshinerecorders (Campbell-Stokes)havebeenoperatingin Thailand,concentratedmostlyin thenorthandnortheast. Most stations (13)werein operationby 1976 (seeTable1.3 inAppendixI). Dataistabulatedbythehour, dayandmonth. Thesedatahavenotyet been incorporated intoasolarassessment scheme. Theyclearlyrepresentaresourcewhichshouldbe combinedwiththedataavailablefromthe MeteorologicalDepartmentandsubjectedto the same analysesas lieted under table 1.2 inAnnexI). Solar radiationElevenbimetallic (BelfortandWeatherMeasure)and10thermoelectric (KippandZonen)instrumentshavebeendeployedby theNEAtomeasure globalradiation. Most of thebimetallic instrumentswere inoperation by themiddleof1977 (Table1.3of Annex I). The thermoelectricinstrumentswereall installedbetween 1979andJanuary 1980. The bimetallic instrumentisnot recommended by theRadiation Commission of the InternationalAssociation ofMeteorology (CSAGI,1958,p.417) forany measurementsexcept dailytotalsof radiation andonly then"withthe reservation thateven ifacalibration factor varyingfrommonthtomonth isused, thesedaily totalsmustbe regarded as havingan accuracyofnot better than5%to 10%." The reasonfor thiscautionis that the instrumentissensitive tothe temperatureof theambient environment aswellas tothe fluxof incident radiation. Temperaturecorrectionmust thereforebe applied.Changesof thecalibrationof theinstrument alsooccurwithchangingangleof incidenceof theradiation. These changes havebeen foundto bevery large for thebimetallic instrument. Thecalibrationisalso afunctionof the incidentenergyitself. Becausethe tineconstantof thebimetallic instrumentislarge andunreliable, this instrumentisnot suitableformeasurementsinvolvingintegrationperiodsshorter thanseveralhours toaday. "Thebest bimetallicinstruments operatedwith the greatestcare are suitableonlyfor dailytotals of radiationinwhich accuracies of 10% are adequate" (Coulson,1975, p.121). The thermoelectricinstrument ismorereliable thanthebimetallic device,butthis is subject tocareful calibration. Theseradiationdatahave beencompiledby the NEAanddailytotals of globalradiationareavailablefor the periodof record. At the thermoelectric equippedstations,powerfailureresultingin failureof the recordingsysteminterrupts therecord. Thedata shouldbe comparedto theestimates madebyAITand toestimates whichcanbe made fromthe NEAandMETsunshine

recorders.

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OtherMeasurements Measurementsof directsolar radiationhavebeenmadeby researchers

at KingMongkut's Instituteof Technology (KMIT)bymeansofpyrheliometer.

B. WINDENERGY

Existing datarelated to the assessmentofwindenergyare those observedbyMEU andNEA.

ObservationsMadebytheMeteorological Department (MET) Surface wind measurementsSurfacewindmeasurements are madeat 66 meteorologicalstations of theMeteorological Departmentof Thailand (seeTable 1.4 in Annex I). Most of the stations areindicatorcupandvane instruments whicharereadevery3hours. The reading instructions followWorld MeteorologicalOrganization (WMO)proceduresof obtaining ameanvalueover aperiodof 2minates. Allanemometeriunderwent acalibrationcheck in awindtunnel priorto deployment. No field

checks on performance aremadeto correct auythingbut catastrophic failure.

Meanmonthlywinddirection,windspeedsand thedirection and magnitude ofthemaximumwindhavebeen obtained for 30 years (1951 - 1980) in the Climatological Dataof Thailand.

Recordinganemometersexist at 7stations. Upper air measurementsAnexcellent networkof 12 pilot balloonstations togetherwith 7rawinsondestations haveexisted overThailand from9to30 years. Streamlineanalysis at thesynoptic hours (00,06, 12, 24 Z)is available for morethan20 years for 12 levels from2,000ft (0.6km) to 60,000 ft (18.0 km). Thetwo lowest levels of 2,000and 5,000ft

are of particularinterest towindenergyassessments. Higher levels serve as valuableguides-fordeterminingthe synopticweather patterns overThailand.

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Observations Madeby theNationalEnergyAdmini.tration (NEA) 11 recording and26 non-reccrding anemometersare maintained aspartf thehydrologicalnetwork by theNEA. Thenon-recordinganemometerseasure 24hourswind passageor run in kilometers, thusprovidingaean24 hourwindspeed. Therecordinganemometers provide arecordhichyield integratedmeanwind speedswithatimeresolutionof ateast 1hour. Both anemometers are mounted at aheightof 2mabovehesurface. Table 1.3 in Annex I sb'zs thatmost (20)of theon-recordinganemometershavebeen inoperation formore than5years.ost of the recordinganemometers,however, have only been functioningforthepast5years.

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Chapter 3

Review ofthe Literature

Praz~7 lmr)u


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REVIEW OF THE LITERATURE

In this chapter,relatedstudiesused for planningthe solarandwindnergyassessmentare presented. Due todifferencesbetweensolar andwindnergy, theliteratureis presentedseparately,except for that relatedtoforeignconsultation.

A. FOREIGN CONSULTANTPLANNING In 1981, as theconsultantto the project,Garstang proposedaesourceassessmentplanfor solar and windenergyfor Thailand.plancan be summarizedas The follows: 0 Additionalmeasurements ofsolarradiationandwind speedwererecommended,especiallyshort time and space scales; " Asynopticclassificationof theweathersystemoverThailandwhichcontrolsthe availablesolarandwindenergywas proposed; and " Athree-dimensionalnumericalmodelwas recommendedto beused to determinethewindenergypotentialover the Gulfof Thailandand over the adjacentcoastalareas. This topic willbe discussed inChapter4in moredetail.

B. PREVIOUS STUDIES IN THAILAND

The reviewof literaturepresentedin this sectionwasmostlydonebyGarstangin 1981.

SolarEnergyStudies Atmosphericcirculationwithits attendantregionsof highand 10;7loudinessand theearth'sgeometryand its rotationaround theictatethat the greatestamountof solarenergyis found betweensuntworoad latitudinalbands - between150 and 3501967). northand south (Robinson,In these regions there is2 aminimummonthlymeanglobalradiationof 500 cal. cm- d-1. The nextmost favorableglobalregionis in thequatorialbelt betweenlatitudes 15* Nand 150 S. Globalradiationisrom300 to500 calcm- 2 d-l throughouttheyear. Thailand,extendingfrombout 50 to 200 N,lieswithinbothregions, and canbe expectedto haveradiationvalues equalto thosequoted above.

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Nodistinctionwasmadein the cloudiness-to-hoursof sunshine conversionbetweentypesof cloudcover. Anunderestimate of thenumber ofhoursof sunshineisnotedand isprobablydue to the fact thathighthinstratiformcloudtransmitsafairamount of the solarradiation.

Errors introducedbyestimatingglobalradiationfromthe numberof hourswith sunshineare claimedto beno greaterthan30 calcm-2 d-1 (7%). Correlationsandcoefficients arenotshownfor eitherestimated sunshinehoursfromcloudiness andmeasuredsunshinehours or for the calculatedglobal radiationfromthesunshinerecordor from theestimated sunshinerecord. The fact that directmeasurements of globalradiation wereavailablefromonlytwo locationslimitedsomeof thesepossible comparisons. Thelengthof recordof theobservationsused variedconsiderably: * GlobalradiationfromBangkokand ChiangMai: 4years from 1968to 1972; * Sunshine recorderobservations for about 13years from 1955 to 1968; and * Cloudinessmeasurementsfor about 19yearsfrom 1951to 1970. Meteorologicalconditionswerenot considered in anydetail. Eight1 monthperiodswereused for conveniencein definingstandardsolar

declination values. The analysisof fluctuationsin dailytotalsof globalradiationand in consecutivedayswith radiationaboveor below certainthresholds is limitedbecauseof the lackof dataandthe generalized climatologicalapproachthat isused. Theoccurrence of cloudsvirtuallyreversestheexpectedannualmarchof solar radiation overThailand. Due to thismarkedcontrolexercised by cloudiness,it isdesirable totreat radiation as afunctionof the atmospheric synoptic scale systemswhichproducethecloudiness. Other studiesThongprasert (1982)made detaileddescriptionswith tablesand diagramsof thehighintensity solarfluxmeasurement technique,which canbe used asastandard forconversionof temperature. Kirtikhara and Siriprayuh (1980) madeastudy ofrelationships betweensolar radiationandsomemeteorologicaldata.

WindEnergyStudies Likesolar power,wind energyconstantly presentin themiddleand upperatmospheremay notbe availableat the surfaceof theearth. The largeplanetary circulations suchas the tradewindsand thewesterlies over the openoceans represent thebestlocations forthe utilization of windenergy. Over land, greatervariabilityisintroduced by topography

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butinthebroadbelts of thetradesand in themid-latitudewesterlies, locations can be foundwhere thewindenergyexceeds500Wm -2 (for -comparisonwith theprevious section,1calcm2c-i = 1.163Wm2,

- 2d-1thus adailyvalue of 350 calcm is .400V m-2 ). Overwideareasof oceansandmore limitedareasover land inthe i-rades and in the westerlies, thewindenergy exceeds 200 Wm-2 . Thailandisin theheartof thegreatmonsoonalbelt of Asia. Surface winds go throughadrastic (180') seasonalreversal. Althoughthe large

scalewinds mayhaveafairlyconstant seasonaldirection (SWmonsoon, -1NEmonsoon), meanwindspeeds arenot known tobe high (


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Theresults presentedagreewith thoseof thefirst study showingthehighestmeanannualwind powerpotential to lie along thecoastlines ofThailand. Regional 3nd seasonalvariationsinmeanwindspeeds areevident from theresultspresented in this report. Maximummeanmonthlywind speeds appear tooccur in Februarywhenmeanvaluesof over5ms 1are reportedin the southernextremityof Thailand. Minimummeanmonthlywindspeeds occur generally duringthewet seasonwiththemonthof Septemberappearingtohavethe lowestwind speeds overmostof the country. During September no station recordsameanmonthlywindspeed inexcess of 3.71-ms . Studies by the King Mongkut's Institute of TechnologyTwo studies ofwindenergy havebeenmadeby researchersat KMIT: Estimated Wind Potential in Thailand by Pinij Siriprukponget al., 1981;and The nalysis of the Wind Situation in Thailand and the Designed LocalWind Turbines by BoonchaiNgernswas, 1981. Inthefirst study, Meteorology Department observations every3hours at53 stations overa13 yearperiod (1966-1978)were used. Wind speeds werenormalized to 10 musing twovalues of the exponentain thepower law: a = 0.14 forh>10m and a = 0.4 forh


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Chapter 4

Design ofthe Study


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DESIGN OF THE STUDY

Thischapterdiscusses the deiignofthe study interms of organizationalinvolvement,relationihips ai.2 responsibilitiesfor particularmeasurements. Additionalmeasurements, measurementmethods,maintenanceandcalibrationof instruments, data processing,trainingand consultation withother agenciesare also presented.

A. ORGANIZATION

Inorderto have the projectoperatedwithmaximumefficiency, twocentersof activitywere envisioned- theMeteorologicalDepartment and tie Centerof Solar Radiation and Wind Calibration. Theactivities ofthese centers are specialized and the projectwasdesignedso thattheycouldmaintaintheirdistinct identities.

MeteorolosicalDepartment The Meteorological Departmentwas expected toplay thelead roleindirecting the Project. During theassessment period, ameteorologist wasto play thekey role indelineating the solarandwind potential.Asmall groupwas to be identified and charged withthis taskwithinthe frameworkof the MeteorologicalDepartment. Asenior levelmeteorologistwasto be designated as aProjectDirector.

CenterforSolarRadiationandWindCalibration

Thenecessityfor continualcalibrationof radiationandwindinstruments, andthedifficulty of routinely carryingout some of the requiredradiationand windmeasurements, dictatedcentralizationof these functions. Carewastaken in the choiceof the location of the center. Two considerationsweredominant: " Availabilityof qualified technical staffand facilities; and " Representativenessof thesite.

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Thetwo requirements weremetby the InstrumentDivision of the MeteorologicalDepartment.

Thecenterwasassigned theresponsibilities of: 0 Measurement of radiationandwindat thecenter; a Calibration of radiationand windinstruments; and * Maintenance of equipment. Asenior instrumentstechniciancapable ofmanagingthe center and

allofthe fieldmeasurementswasto be appointedas the supervisorof thecenter.

B. ADDITIONALMEASUREMENTS

Beforediscussingthemeasurementmethods used bytheproject, it is necessarytodiscuss themeasurements used (and rationale)for solar radiation (directradiation,global radiaticn,and diffuse radiation) andwind energy.

SolarRadiation Planning forthe useof solarenergy requiresat least the following

measurements: * Monthlymeansofthe daily totals of directand diffusesolar radiation; * Monthlymeansof the dailymarchof direct anddiffuse solar

radiation; 0 Statistical dataon thefrequency distributions of days

withtotals of direct andglobal radiationabove andbelow pre-determined levels; and * Information onthe spatialdifferences in direct anddiffuse

radiationwhichmay accompanythe abovetemporal changes. Anym~asurementprogram for the use ofsolar radiationmust also

address thequestion ofhow the solarenergy ismostlikely to beused. Thereare fourbroadapproaches to SolarEnergyConversion

System (SECS): * Lowgradesolar heat;

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* Highgradesolarheat; * Direct conversion toelectricity; and o Photosyntheticand biological conversionprocesses.Devicesforthe conversionof solar energytolow-grade heatinclude waterheaters,solar stills, cookers,driers, refrigerators and pumps,solarponds and low temperaturesteam turbines. Most of these devices useasimple flat plate collector, converting solarenergy toheat whichis absorbedby aworkingfluid. Flat plate collectors canconvert80% or moreof the solarradiation toheat reachingoperating temperaturesof 50 to 95*C. The flatplatecollectoruses boththedirect andthe diffusebeamradiation. Highgradesolar systems focus the direct solarbeamuponacollectingsurface. Highgrade circularparabolicmirrorscan concentratethe directbeam uponacollector to reachtemperatures of 3500*C. Crudeparaboliccollectors achieve temperaturesof 500'C. The focusingcollectormust"track"thesun and iscritically dependent upontheavailability of direct solarradiation,performancebeing seriously impairedby cloudiness. The directconversion of solar radiationintoelectricitymaybeachievedeither by the thermoelectricprocessor by photovultaicpowergeneration. Maximumefficiency of thesesystems iscurrently about 15%.Anefficiency ashigh as 30% hasbeenpredicted. Thecost of the solarcellisdroppingprogressively but isstill highenoughfor themethod to bemostly applicable to specialpurposessuchas chargingof batteries at remote telecommunicationor measurement sites. Photosyntheticor biologicalconversion of solarenergyachievedbyplantingfast-growing,woody plants or treeswhichhaveahighphotosyntheticefficiencywill be left to the Biomass assessment. ForThailand the greatestpotential useof solarenergywouldappeartobe in the conversion to lowgrade heat. Emphasis inthemeasurement programfor thisprojectwas therefore to be placedupon thisformofsolar energyconversion. However,bothhighgrade solarheat and thedirectconversionof solar radiation to electricityhavepossiblefutureapplicationsin Thailand. Basicmeasurements requiredforplanning the useof thesesystems wereincluded. The evaluationof theexistingdatabase and therequirements of thekind of solarradiationenergyconversionprogramwhichcanbe envisioned for Thailandrequired the followingmeasurements:

DirectRadiation Asolar trackingdirect beampyrheliometer wasrequiredtomakecontinuous measurementsof directsolar radiation atonelocation.

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An instrumentwiththe followingcharacteristicswasrequired: -2min- I Sensitivity 5-6mV/calcm

Impedance 200 (approximately)Temperaturedependence 1%overrange -30 to+40*CLinearityof response Linearup to4calcm2 minResponsetime 4secmaximum

The instrumentmustbe temperature compensatedandhaveareliable solartrackingmechanism.

The signalshouldbe capableof being transmitted toaremoterecorder. The instrumentitselfmustbe housed inaweather-proof casecapableof exposure inallweather. The instrument mustbe attachedto an electrically drivenequatorialmount forsolar tracking. The output signalshould preferably be recordeduponastrip chart and simultaneouslydigitized and recordedonmagnetic tape. Ifthe lattermethod isused, thetape musteither be compatiblewith acomputeror equipment toconvert the recording tocomputercompatible tapemust be acquired. Ifthe digital recordingmethodisadopted,thenmuchof thedifficultieswhichare encountered in using thestrip chart recorderwill be avoided. Standard procedures canbeused toprogram theoutput inanydesired timeinterval above4sec.

Global radiationGlobalradiationmust be measuredat thesame locationwheredirect solarradiation isbeingmeasured. The WorldMeteorological Organization

(WMO)(1965) has definedthree classesof pyranometersonthe basisof overallperformance. Allof the pyranometers requirecalibration with respect toaprimaryradiation standard. Noneisclassified as a standardpyranonteter. Table 4.1 gives theclasses andtheirrespective characteristics.

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Table4.1 ClassificationofPyranometers

1st Class 2ndClass 3rd Class Sensitivity(mWcm- 2) 0.1 0.5 1.0 Stability (%changeperyear) 1 2 5 Temperature (maximumerrordue to changesof ambienttemperature.- %) 1 2 5 Selectivity (maximum errordue to departurefromassumedspectral response-.) 1 2 5 Linearity (maximumerrordue to nonlinearitynot accounted for- %) . 1 2 3Timeconstant (maximum) 25 sec 1min 4min Cosineresponse (deviationfrom that assumed,taken at sun elevationi0' onclearday - %) 3 5-7 10 Azimuthresponse (deviationfrom that assumed,taken on clear day- %) 3 5-7 10

The rating,accordingto thecriteriain Table4.1 ofpyranometers whichwereavailablein 1965 is the following:

Diffuse radiationDiffuseradiationwas to bemeasuredat the same locationwheredirect and globalradiationwereto bemeasured. The observedvaluesof diffuse

radiationcan be usedin calibrationof radiationinstrumentsby comparing themto the observedvalues of direct andglobalradiation.

Diffuseradiationis measuredbypyranometerwithashadowband. Theappropriatemethodwas tobe used tocorrect fortheportionof sky screenedby theshadowband and forelevationof measurements. However, forconvenience,tabularvalues of the shadowband correctivefactor, applicableto average conditionof partlycloudyskies, are listedby manufacturerbelow.

First Class: Selectedthermopilepyranometers

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Second Class: Moll-Gorczynski (Kipp)pyranometer Eppleypyranometer (alsocalled 1800 pyrheliometer) Volacinethermopilepyranometer Dirmhirn-Sauberer (star)pyranometer Yanishevskythermoelectric pyranometer Spherical Bellanipyranometer

Third Class: Robitzschbimetallicpyranometer

Since 1965 severalnewtypes ofpyranometers havebeendeveloped. Twobythe EppleyLaboratoriesarebased uponthermopiles. Theprecisionspectralpyranometerof Eppleymeets the criteriaforafirst class pyranometer,while theEppleyblack-and-whitepyranometer fallsinto thesecondclasscategory. Itwasrecommended that theCenterforRadiationCalibrationbe equippedwithan EppleyPrecision SpectralPyranometerwithelectrical compensationfor the dependenceof sensitivity on ambient temperature, opticalcompensation fordeviation of responsefrom the cosinelawand provisionfor the useof broad-band filters. Specificat-onsof the instrument (1973) arc shownin Table 4.2.

Table4.2 Specificationsof theEppleyPrecisionSpectralPyranometer -Sensitivity 5mV/calcm2 min-I (approx.)

Impedance 300 Temperaturedependence 0.5% from-20 to40*C Cosineerror 1%over anglesof0*to 800 Responsetime (I/e) 1sec

-Linearresponseup to 4calcm2min-1

An alternateinstrument to the EppleyistheSpectrolab Pyranometer.Theoutputsignalof thepyranometer shouldpreferablyberecordedbyboth astrip chart recorderand in digitalform asdescribed for thepyrheliometerabove.

WindEnergy Anassessment of thewind energypotential ofacountryrequireswind measurements onarangeof timeand spacescales. Longtime andlarge

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spacescalesprovidetheclimatologicalbackground and provideafirst approximationofwhat canbe expected. Such largescaledescriptions areavailableforThailandas describedinearliersections. Descriptions ofwind speeds ontimescales ofamonthor lessandspace scalesof regionsor less aremuchless certainforThailand. While thewind measurements at relativelylowlevelsexist,these datahavenotbeen systematicallyanalyzedtoprovideabasisfor assessment of thewind energypotential of Thailand.

Planning forthe useof wind energyrequires: " Hourlyaveragewiudspeeds atarepresentativeheight at or near 10mat asufficient number of locations todescribe regionaldifferences and for asufficientperiodof time to describeseasonaldifferences; " Statisticaldata on thefrequencydistributions ofdays with windspeeds aboveor belowpre-determinedmeanwindspeed levels; " Statisticaldataon the diurnaldistribution ofwindspeed af;representativelocations andtimes of theyear; * Measurements of windspeedsat selected sites,at least, three levelsbetween 10 mand50 m. Measurementsof temperatureandhumidityat thesesites and levels

are desirable; and * Capability toobtaindetailedwind speed distributionsin the horizontal (xandycoordinates) and from thesurface to 300m(zcoordinate) at selectedsites. As forsolar energy,anymeasurement programfor theuseofwind energymustalso address thequestionof howthewindenergyismost likelytobe used. Wind EnergyConversionSystems, (WECS),canbe dividedinto three

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Evaluationof theexistingdatabaseand the requirements ofthe kind ofwindenergy systems. tobeemployedin Thailandindicatethefollowing additionalmeasurements.

Wind speed and directionArecordinganemometershouldbe usedfor measuringwindspeed and

direction. Mostof the 12 NEArecordinganemotieters are located inthe north andnortheast. Onlytwo are locatedOIL the Gulf coastat BanLa MaiandBan KhlongMuang. Thenearestrecordinganemometerto theregion southwest (SamutSongkram)and southeast (BangPakong)of Bangkokwhere windmillsarestillbeing used (U.N., 1976).

ThesmallWECShas beenmostwidelyusedfor liftingwater. Itcan also beapplied to crop dryingand the productionof small amountsof electricity for relativelyspecializedpurposes. Integrated solar-wind systemsmayusesmallWECS forsalt production,desalinizationof saline or brackishwater, fish farmsandother specialized applications. The smallWECS is oftenconstrained toagivensite and heightabovethe ground. Itcanutilize relativelylowwind speeds andcanoperateon an intermittent basiswithoutany requirement for thestorage of the energy.

Theintermediate WECScanbeappliedto smalllocalizedindustry and commercial operations suchas cooling,airconditioning,electrical productionandthe pumpingofwater to impoundments or irrigation systems and desalinizationor purificationof salineor contaminated water. IntermediateWECS inthe rangeof about 250KWhavebeenused elsewhereas auxiliaryelectricalsuppliesfor small andremotecommunities which are outsideanymajor electricalgrid andmust dependupondiesel poweredgenel~tors for theirelectricity. Theintermediate WECSrequires relatively goodmean annualwindspeeds (>5ms-1 )tobe effective and great caremust be takenwiththe siting,in boththehorizontal and in theverticaldimensions.

LargeWECS are stillprimarily in the development stagebut sufficient testingof prototypemachineshas nowbeen done towarrant theconsideration of these largemachines. Economy'achievedbythe scaleof theselarge machines suggests that electricalenergycan beproducedat favorable locations, andat acompetitivecost.

Recordinganemometers capable of accuratelydetermining the total hourlydurationofwindvelocity are requiredfor thecompilationof diurnal,inter-diurnal,monthly,seasonalandannualpowerpotentials.

TheNEArecorders areall mountedat 2mabove thesurface. Whereas this observationwillbe usefulin showingthe generaldistributionof wind speeds and canbe usedwithcaution inestimating thepotential for smallWECS, there isan urgent needtomakecontinuous windspeed measurements at greaterheights and atcertainkey locations. Four recordinganemometers wererecommended for thisproject,three for deployment andoneas astandbyreplacement instrument.

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Thethree recordinganemometerswereto beplaced to providedetail ofthewindregimesof the:

0 Gulf coastline; * Centralplains; and 0 NEplateau Wherepossible,at * BanKhlongMuang; 0 KhonKaen; and * NakhonSawan. Eachanemometerwas tobe placedat 10mabove the ground inawell exposed (freefromobstructions such asbuildings ortrees) location. Therecordingsystemwasto incorporateamicroprocessorwhichcould bepre-programmed toprovidearange ofwind speed statisticsincluding: * Meanhourlywindspeed baseduppn an integrationof

the instantaneouswind; 0 Varianceofthemeanhourlywindspeed; a Standarddeviationof themeanhourlywind speed; * Anestimate of gustiness; * Meanhourlywindpower density (W m-2);and 0 Daily (24h)meanwindspeed andpowerdensity. Thedatawas to printedinhard copy formandrecordedonmagnetic tape. Winddirectionwas tobe recordedeveryhour as amean directionand as astandarddeviationin degreesfor that hour. Profile measurementsExtrapolation ofwind speedmeasurements fromoneheight toanother height dependsupon atmosphericstability, the aerodynamic roughnessof

the surrounding terrain,and upon topography. InThailand itmaybe unlikelythat theneedto estimatewinds above

10 mwillexist inany locationexcept thosesurrounding and over the Gulfof Thailand.

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Center forSolar RadiationandWindCalibration The Centerwas to take responsibility for solarradiationandwind

measurementsof the Projectand also forcalibrationof solarandwind instruments. TheCenteritselfwas tomakeobservations for data collectionandcalibrationpurposes.

Solar radiationAt the Center,solarradiationmeasurementwas tobemadeby four kindsof instruments: * NormalIncidencePyroheliometerwithsolar trackerfor

measuringdirectsolarradiation; * PrecisionSpectrumPyranometerfor globalradiation

measurement; * PrecisionSpectrumPyranometerwithshadowbandfor diffuse radiationmeasurement;and " AngstromPyrheliometer (2sets)whichbelong toMET. Theseinstruments areused as theNational Standard Pyrheliometersfor directradiationmeasurement. indForwindmeasurement,windspeedand directionwere to be observed at theCenter by an anemometerandawindvane.

SolarRadiationMeasurements Planningforsolarradiationin thefield canbedividedinto two steps: site surveyand installation. Site surveyThe objectiveof asite surveyis to find asuitableplacefor solar

radiationmeasurement asrecommendedby WMO. Thesite forsolar radiation measurementshould freefromanyobstructionabove the planeof the sensing element. It shouldbe locatedaccordingto the followingconditionswhere: " Shadowswill not be cast on itat any time; * It is not closeto light-coloredwalls orotherobjects

likely to reflectsunlightonto it;

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* Itis notexposed toartificial radiationsources; and * Noobstructionover theazimuthrangehasan elevation

exceeding 50betweenearliest sunriseand latestsunset. Itisalsouseful, forreferencepurposes, to notethe instrument'saltitudeabove meansealeveland its geographical coordinates.

InstalZationWhenthesitehas beenchosen,the instrument willbe installed

according tothe appropriate methodfor eachkindof instrument. This sectiondeals withhow toinstallapyranometer,ashadowband for shadedpyranometer andasolar tracker fornormalincidence pyrheliometer.

a Pyranometer The pyranome:er should be attachedto the rigid stand or tothe tripod. Thenthepyranomnter shouldbe orientedso that the retaining screwislocated approximately south (for theNorthernHemisphere)of the receivingsurface. Thepyranometer should then be securedlightlywiththisscrew. Afterthe instrumentislevelledwith theaid of the levelling screws and the circularspint levelis mounted on the tripod,the retaining screwshouldbe tightened, takingcarethat the settingisnot disturbed. When properlyexposed,the receiving surface ishorizontal and theleads emerge on thepolewardsideof the pyranometer base. The standusedshould be sufficiently rigid so that severe shocks to the pyranometer willnot occur throughout the periods of exposure.

0 Shadowband forshadedpyranometer The shadowband stand shouldfirst beplacedon the speciallyconstructed supportingstand. Thenit shouldbeverified so that the N-S orientationis correctand the base islevel. The latter should be securedrigidlyto thesupportingplatformwith four belts. The twowingnuts dampingthe sidebars carryingthe shadowband shouldbe loosenedand each bar reset so that the0'markof thedeclination scaleengravedonthebar isscale. Bothwingnuts shouldthenbe tightened.

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0 Calibrationof thepyranometer AsecondEppleyPrecision SpectralPyranometerwas tobe acquiredandcalibrated againstaprimarystandard. The instrumentmaybecalibrated bythemanufacturer andkept asasecondarystandard forfieldcalibration purposesat theCenter only. Calibration of the Centerpyranometerand recordingsystem wasto be carriedoutonceayear. The pyranometerwas alsoto be checkedagainstthe calibratedpyrheliometer by shadingthe pyranometer.

0 Calibrationof theKippand ZonenThermoelectricpyranometers Tenthermoelectricpyranometers have beendeployed byNEA. These instrumentswere tobe calibratedby comparisons withthe Center'sstandardpyranometer.

0 Calibrationof theBelfortandWeather Measurebimetallic pyranometers

Four oftheel'vqnbimetallic pyranometerswereco-located with thermoelectric instruments. Thebimetallicinstruments at these locations wereto be calibrated eachmonth against the thermoelectricinstrument and acalibrationfactor appliedto thebimetallicinstrument onamonth-to-month basis.

WindInstruments Maintenanceand calibration ofwind instruments arenecessary for

continuity andreliabilityo'the observeddata. Maintenance and SparesFor continuityofdata, spareequipment wastobeavailable at the

Center. CalibrationCalibrationofwind instrumentswasto be doneat the Centerusing awindtunnelasmentionedpreviously. Two constant-speed,D.C.motors

were tobe obtained for field checksof theanemometers. Thetwowind speeds correspondingto therotationrate of themotorswere to represent twopoints on the calibrationcurve. Allgenerator-typeanemometerswere tobe checkedwith theconstantspeedmotors onceayear.

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At the NEAautomatic aind recordingstations (Lambrechttype), a comparisonwas tobe madebetweenacalibrated instrumentwhichhas recentlybeenput throughthe tunneland the fieldinstrument. The comparisonshouldbe conducted overaperiodof at least 5days.

Allcalibrationandcomparison data forall anemometers wereto be carefullycompiledand recorded. Instrumentswhichhavebeen foundto have systematicoffsEtswereto be labelledand correctionfactors established and appliedto existingand futuredata. Instrumentswhich displayrandomerrorsor malfunctionswere to be repairedor returned to themanufacturer. Whenfixed,wind tunnel calibrationwas again required. Datatakenbyinstrumentswithnon-systematicdiscrepancies were tobe removedfromthe dataarchives.

RegionalCalibration For accur;-cy ofNational StandardPyrheliometer,calibration of theinstrument at . WMORegional Centerisrequiredat least onceevery5years. The nearestWMOregionalcentermaintaining workingstandardpyrheliometers isAustralia.

E. DATAPROCESSING

One criticalobjectiveof thisprojectwas togenerateausefulset of numericalvaluesof solarandwindenergywhichwere toserve as aframe of reference for estimationsof potentialenergyusing theengineering specifications of thevariousconversion systems.

To makereliableestimates of the solar andwindenergy potentialof Thailand,detail isneededonatimescaleshorterthanonedayand applicable to specificlocations. Onlyin some instanceswillannual dataalone be anadequatemeasureof thepotentialof the resource. The emphasisin theanalyticalmethods is therefore ondeterminingreliable estimates of solarandwind energyonshort timeand space scales. Care was exercisedtodeviseamethodwhereby theseshort timeand spacescales could be extended to the largerdomain.

SynopticClassification Inordertounderstand howdatawasto beprocessedit isnecessary to go into somedetailabout synopticmodelsas theyprovidethe framework

for thedatacollectionprocess.

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Thestudyof solarandwind energypatternsin termsof synopticmodelswas proposedbyGarstang (1981). Annualaverages ofwindand solar powerare not sufficientto describethereiourceinthe stronglyseasonal climateof Thailand. Seasonalvariationsin atmosphericcirculation over Southeast Asiagovern boththe surfacewindspeedsand the amountof solar radiationreceivedat th6earth's surface.

The solar andwindpower potentialof Thailandneeds tobedefined on aseasonaland intra-seasonaltime-scale togetherwithany spatialvariation in theresource,across thecountry,whichmayaccompanythetime changes. Thepurposeof definingthe resourcein time andspace scaleswhich are determinedby the atmospheric fields of motionisto: 0 Eliminatethe smoothingimposedby averagingoverthe annual

cycle; * Determine themagnitude of theresourcein spaceand timeas afunctionofatmospheric fieldsof motion; 0 Tiolate thetimeand spacescales important to theresource to provideguidanceon the assessment of theresource. For example,knowledge of the time(s) and tha location(s) of the maximumvaluesof the resourcewill peruitefficientmeasurements tobemade and specificapplicat.ons suchas cropdrying tobe assessed; and a Ifcertainatmosphericregimescanbe identified as optimum energyregimes, thenthe generalkinematic and thermodyamic properties of theseregimesmaybe characterized in termsof amean state foreachregime. Themeanstatemay thenbe used as input tonumericalmodelscapableof providingvaluable estimatesof the resourcewhichareeconomicallyimpossible

toduplicatewithmeasurements. Conditions are characterized in terms of synopticmodelsof the atmospheric systemswhich controltheday-to-day weatherof Thailand. Becauseof themonsoonalnatureof the flow,classification ismade

in terms of the: 0 SWMonsoon,and the * NEMonsoon. Eachday is designatedas aSWorNEMonsoondayaccording to the streamline fields overThailand. Daily synopticstreamline chartsat 2,000 ft, 5,000 ft, 10,000 ft, 15,000 ft, 18,000 ft and 20,000ftat 00 GMT (07TST) and 1200 GMT (1900 TST) areused as the datasource. Ambiguityin southerly (northerly)flowoccurringover Thailandduring

the NEMonsoon (SWMonsoon)isresolvedin termsof thedepthof the flow.

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SWMonsoonSynopticModel When the SWMonsoonis established, southwesterlyflowextendsthroughmuchof the lowertroposphere (below20,000ft). Equatorialvortices embeddedin this flowcanoccursinglyor in extended (Eto W)vortex trains. In the lattercase, the asymptotesof convergenceand divergenceconnectingthevortexcenters and theneutral pointsmaybe evidentinthesurfacepressure field asweaklowpressurecenters or anextendedthroughof lowpressure. The !roughof lowpressureis oftenreferredto as the EquatorialTroughor IntertropicalConvergenceZone (ITCZ). TheEquatorialTroughis frequentlycoincidentwithlow surfacewindspeedsand highcloudiness. Maximumcloudiness is locatedover thevortex centers. Thezone of cloudiness (sometimesdefined in the surface pressurefields) separates the highersurfacewindspeedregions andlower cloudiness

to the southand to thenorth. Figure 1(AnnexIII)illustratesamodel of the equatorialvortex embeddedin the 2,000 ft streamlinefieldof the SWMonsoon. Three categoriesaredefinedforthis model: CategoryI: SWto Sflowboundedby the equatorialtrough (lowersurfacepressuresand highercloudiness) to thenorth. Ndte that cloudinesswillincrease due to convectiongeneratedbyorographymainly over SWThailand.

Category II: EquatorialTrough: zoneof lowerpressureand highcloudiness,linkingthe neutralpoints and vortexcenters of the vortextrain. CategoryIII: NE to NWflowbounded by theequatorialtrough

as definedin CategoryIabove. Figure 2(AnnexIII) shows an exampleof avortextrain lying across SE Asia.

NEMonsoon SynopticModel Whenthe NEMonsoonis established,highpressuresystems dominatethe Asiancontinent. The anticycloneoverChinaproducesNE outflowfrom the surfacetoabove 5,000 ft. The Tibetanhigh lies to thewestof the anticycloneoverChina and the subtropicalPacificanticycloneto the southwest. Ridgelines extendequatorward fromtheseanticyclonesmarkingthe locationbetweennortherlyand southerly flow. Theanticyclonesare separatedbycolumns and frequentlyby shallow (usuallylessthan 5,000ft deep)cyclonicvortices.

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Thehighpressuresystems migrateslowlyfromwest toeast andshift inlatitudinal position. Duringthe transition period, thesubtropical anticyclone of the westernPacificfrequently encroaches uponSoutheast Asiaresultingin shallowsoutherlyto southeasterly flowoverThailand. Whensuchincursions followanortheasterlyanticyclonicoutbreak,rains extendovermuchof southeast and northeastThailand. The southerlyflows of theNEMonsoonalperiodare distinguished fromthe southerlyflowofthe SWMonsoonby the fact thattheformer is shallow (5,000 ftand less), while the latter is deep (>8,000ft).

Figure 3(AnnexIII)illustrates themodel for theanticyclonic flow of theNEMonsoon. Streamlines are shownat 5,000 ft. Four categories are definedforthismodel:

Category IV: Northeasterly,becoming easterlyin thescuth, flowover Thailand. The anticyclonicoutflowfromthehighpressure (CA)over Chinaisshallow.

CategoryV: Northerly tonorthwesterlyoutflowfromtheTibetananticyclone (TA).

CategoryVI: Southerly tosoutheasterly flowonthewesternsideofthePacificanticyclone(PA). Thiscategoryincludes thetransitioal periodwheresoutheasterlies follownortheasterlies.

CategoryVII: Anticycloniccolumns or weak(shallow)cyclonicvorticesseparating the majoranticycloniccenters.

Figure4(Annex III) showsan exampleof the NEMonsoon. At eachofthe surfacewindandsolar radiationstationsin Thailand,

it is recommended thatevery dayis classified at twosynoptichours, 00Z (0700)and 12Z (1900)according to the sevencategorieslisted in Chapter4,SectionAfor a10 yearperiod. Therequiredobservations are the streamlinechartsatOOZ and 12Z.

Frequency distributions for eachcategoryat eachstationwilldefine the time changesat thatlocation. Byexamining thedistributionoverthe country (all!3':ations), the spatialchanges in categorieswill allowa determinationof regions. Representativestations ineachregioncan thenbe chosen. The windand solarenergypotential for the representative stationcan thenbe determined foreachcategories. Alikely resultis that onlyafew (I to 3)categorieswillcontain the bulkof theenergy ( ;70%). Knowledge of the timeandspace distribution of thesedominantcategories willprovide:

" Anassessment of theresources; * Abasisfor decisiononwhetheradditionalmeasurements

areneeded;

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0 Guidanceas towhereandwhen tomake thesemeasurements;* Guidanceonthe kindofwindor

be used; andsolar systemwhichshould

* Aframeworkinwhichnumericalestimatescanbe carriedoutand appliedin relativelysmall space scales.

ModelCalculation Itappears tobe evident fromexistingdataand studies that the potential for IntermediateandLarge WindEnergyConversion Systems is confinedto the Gulfof Thailand,its immediatecoastline and the Indian Ocean coastal region. Workelsewhere by Garstangand his associates

(Garstanget al., 198C a,1980b)hasshownthat amesoscalenumerical modelcoveringadomainlikethe Gulf of Thailandis capableof providing areliableestimate at the locations overthe coastallandand searegions ofmaximumandminimumwindpower potential. The studiesindicated that theestimates of windpowerby themodelare as goodas estimates based upon measurements where measurements areavailable. Sincemeasurements are available at only isolated locationson landandnot availableat allover thesea, suchmodelcalculations areextremelyvaluablein the assessment of windpowerpotential. Furthermore, themodelpredictswindsat 12 levels in theatmospherewith considerable resolutionpossiblein the lowest 300m. Realistic

boundary layer theoryis dependent uponatmospheric stability, surface roughness and heat transfers; andallowsatruemeanlayerwind tobe calculated commensuratewith theheight andarea sweptby any given potentialwindturbine rotor. Modelcalculationsover thecoastalregionsof the Gulfof Thailand and overthe Gulf of Thailandwouldbe carriedout for twoof thedominant synopticregimes. The areacovered wouldbe approximately800 kmx500km from140 to 60 Nlatitude and 98 to 103' Elongitude. Estimates ofwind power potentialwould be madefor at leastevery 20x20 kmgrid interval and possibly forevery 10 x10 km grid interval. Theresolution of the modelcalculation would depend upon thecomputercorestorage required

by this relatively largedomain. The modelwouldrequire the followingrepresentativevaluesof the two dominantsynopticregimes: * Large scale synopticconditions: surface,850and 500 mb streamline andpressurefield analyses; 0 Representativerawinsonde; * Mean latitude ('N) of domain;

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a Landsurfaceconditions: albedo roughnesslength shelterheightmean temperatureat initialization soilcharacteristics: density specificheat

diffusivity wetness; and

0 Seasurfaceconditions: seasurface temperatureof bothGulf of Thailandand IndianOcean coastalwaters. Itwas recommended (Garstang,1981) that themodelcalculationsbe carriedoutat theNationalCenter of Atmospheric Research(NCAR), Boulder,

Colorado. The three-dimensionalmesoscalenumericalmodeliscurrentlyon theNCARCRAY computer. Runningthe modelat NCARwouldbe themost efficient approachin terms of timeand money.

Theconsultant wouldsupervisethe modelcalculations andprovide theproducts to the Thaicounterpart agencies. Theproductwouldconsist of spatialdistributions ofwindand windpowerdensityatvarious levels (e.g., 10 m,50m,100m,150m)and integrated meanlevelwinds (e.g., integrated over50 and 100m)over the domaindescribed above. Grid intervalswouldbe 20 x20kmor 10 x10 km. Tabulationsof thewindpower densityfor all grid points foreach of twonumerical simulationswould be provided. Thechoice ofatmospheric conditions for the twonumerical simulationswouldbe baseduponthe results of the synopticclassification. The twodominantwindenergyregimes would thenbe chosen.

Theresultsof thenumericalpredictions wouldbe compared tomeasurementsat the points where dataareavailable. Thedistributionof wind power densityresultingfrom themodel calculations wouldprovideasound frameworkwithinwhichthe windpower potential of the Gulf coastand overthe Gulf of Thailandcouldbe assessed. This frameworkwould represent the basis uponwhich adecisioncould be madefor thedeployment of Intermediateand Large ScaleWECS. Inthe absenceof modelcalculation, uncertaintywill persistas to thewindpower potentialoverthecoastal areas.

Acautionary noteisrequiredon the above assessment ofusing the 3-Dmodelover the Gulfof Thailandandsurrounding coastalregions. The modelhas workedbestwherethe coastalregionshavebeen flat. Where topographyinthe formof coastalmountain ranbesor significantincreases in theheight (slopes)in thecoastal plainexist, resultshave beenless satisfactory. The topographicconditions aroundthe Gulf of Thailandare mixed. The existenceof significant mountains on theMalayPeninsulamean thatthe modelresultscannot bepredictedwithcertainty. Theopinionis thattwo modelruns wouldbe worthwhilein ternis of theexpectedbenefits ifsuccessful. However,this doesmean thatthe model Jculationsare experimental and the results arenot certain.

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WindEnergy Allwindrecords fromstationswith anemometers above 10mshouldbe

re-analyzed. Theanalysis should take particularnoteof the following: " Height changesof the anemometerat agiven station: the historicalrecordof the stationshould be carefullyexamined for any changes inheightof theanemometer sensorheadat that station; * Calculate thevalueof thepower lawexponent, a,at all stationswhereachange in heightof theanemometertook place; * Normalize allwind speeds toacommon heightof 10 mkeeping

day (definedas sunrise+1hourto sunset) andnight (defined as sunset to sunrise+1hour)separate. The calculated exponentsshould be usedif they displayasystematicseasonal and/or regional distribution. Ifnot, thena=0.14 should be used; * Compile the normalizedwind speedsby synoptic categoryand obtainmeanvalues, variancesand standarddeviationsof the wind foreach category; * Rankthecategoriesaccording to themagnitude of the meanwind speedin eachcategory. Calculate themeanwindpowerdensity

(W m-2 )for eachcategory; " Use the frequencydistributionof categories fromthe 10 yearsample to determinewhether individualcatLgories containlarge amountsof wind energy comparedto other categories; * Determine the spaceand timedistributions of windpowerdensity-(Wm2 )overT.alandaccording to the frequencydistributionsof thedominant categories; " Obtain standardmonthlymeanvalues ofwind speed andpowerdensity aswell asmeanvalues of these quantities for the

same intervals of timeused in the analysisof thesolar energy; and * Produce afirstestimate ofwindenergy potentialforThailand. As forsolar energy,this distributionshould beregarded as the first estimateof thewindpowerpotentialfor Thailand. Futuremeasurements and estimatesmust bemeasured againstthis first estimateandanychanges musthave the supportof additionalobservationsand/or calculations.

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Thecourseto be offeredat METwas todealwithbothbasicphysicsandphysicsas appliedto the atmospheric system. While thecoursewas todealwiththebasic principles uponwhichmeasurements of solarand windenergyare found,it wasnotto dealwith the technicalorengineeringdetailof theseinstruments. Thecoursewas designedto dealwithconceptsof analysis,application and archivingof data. Durationof trainingwas to be approximatelyonemonth. Participantsof the trainingwereto hold,at leastBachelor'sdegreesin science orengineering. One trainingexpertwasrequiredto be the lecturer. sianInstitute of TechnologyCourses offeredat AIT inthe fieldsof EnergyTechnology and Computer

Applicationwere tobe utilizedfor theproject. Inthesecondyearof operation, twomembersof the componentwere tobe trainedat AITin RenewableEnergyResources, whereonetrainee wouldfczus on energy resourceand utilization (solar&wind), and the other: on solar&wind instrumentation (calibration&maintenance). Inthe thirdyear, three persons were to be trained as in thepreviousyear; one inenergyresource and utilization (solar&wind), and twoin solar &windutilization (calibration&maintenance). Durationfor eachtrainingsessionwas one semester,or approximately 3 months.

OverseasTraining Oneof themainobjectives of the Solar/WindResourceAssessment Component was toprovidecalibration of solarand windinstrumentswhich are beingusedin METandotheragencies. Theofficialswho performthe taskshave to followup the progressof theoreticaland practicalapplications of solar andwind instruments; therefore, international training forstaffmemberswas essential. Thetrainingcourses described in "In-CountryTraining"were notdesigned toprovide thespecifictechnical detailand engineering instructionwhichisrequiredfor calibration,operation and maintenanceof solar and.wind instruments; such instructionwas tobe providedby engineeringand technicalcentersequippedwith facilities to carryout such trainingtoonlyone or two select individuals. The contentof trainingwasto includetheoreticaland practicalapplicationof instruments, selection of location,installation,calibration, operation,servicesandmaintenance. Thepersonnelwhowereto be selectedwere to be in supervisorypositions in charge of the calibration,operation,mainterance and datacollectiontasks of the solarandwind energy program. Eachwas tohold aBachelor's degreeinengineering,physicsormathematics. Both individualswere tohave completed thetraining course.

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I. CONSULTATION

ForeignConsultant Theapplicationof meteorology tothe assessmentof solar andwind

energyisrelativelynewto Thailand, and theforeignconsultantwas requiredto:

" Evaluate thedatacollectionsystemand toprovide recommendations for strengtheningthesystem; and

" Advise on the initiationof proceduresfor assessmentof solar andwind dataforenergy productiveuse.

Local Consultant Due to the complicatednatureof the instruments, observation,and

analysisof solar andwindenergy, the localconsultantwasrequired to adviseon:

* Calibrationof instruments; " Siting ofmeasuring instruments; * Processingof thedata formonitoringthemeasurements; * Analysis ofdata for assessmentof solarand windenergy

availability; and * Reliabilityof observations.

J. COOPERATIONWITHOTHERAGENCIES

Calibrationof Instruments TheCenter forSolarRadiation andWindCalibrationwas to take care of calibrationof solarandwindinstruments. Instrumentsfromanyagency

maybesent forcalibration at theCenterwithout charge. The existing instruments at theObservationDivision andAgrometeorological Division oftheMetrologicalDepartment,NEA,Electricity GeneratingAuthority (EGAT)anduniversitieswereexpected to becalibrated at the Center.

Installation of Instruments Installationof instruments wasneeded tomeetthe requirementof

additionalmeasurement. This had tobe in cooperationwithDivisions intheMeteorologicalDepartment,NEAand otheragencies, asnecessary.

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-------

-------------- -------------------

DataCollection Inaddition to themeasurementsmadebyMET formeteorologicalpurposes,

measurementsmadebyNEAand MIT(seeChapter2)wereto be usedin analysisof solar andwindenergypotential. Close cooperationwas tomake the data available in time.

DataProcessing Withinthe timeperiodof the project,itis expectedthatMETalonecouldnot completethe analysisof existingandnewdata. Theroleofuniversitiesin this assessmentwasvery importantandeffortwas givento encourageuniversityparticipationin theassessment, particularlyAITandKMIT,whicharealready involvedinsolar andwind energytechnology.

K. PERSONNELTIMECOMMITMENTS

Thefollowing tablereveals thetimecommitments andfunctions for projectpersonnel.

Table 4.3Personnel timecommitments

Personnel Year I Year 2 Year3(ManMonths) (Manmontha) (ManMonths) Total Center for Radiation InstrEng 24 24 24 72 and Wind Calibration

AsistInstr Eng 24 36 24 84

Meteorological Meteorologist 12 12 12Department 36 AssistMeteor. 24 12 12 48

ForeignConsultant 9 3 3 15Local Consultant - 7 9 16

Total (OtherthanConsultant) 84 84 72 240

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L. BUDGET

Thebudget fortheprojectwasTechnicalAssistance

ForeignConsultantation $63,000Services (Institution&Support) $49,680

CommoditiesSpares&Equipment $51,400Supplies,Materials&Labor $51,000

TrainingOverseas $46,500Local $ 9,000

OtherNEA $ 3,030RoyalThaiGovernment $ 13,800

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Chapter 5

Techniques and Procedures


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TECHNIQUES AND PROCEDURES

In thischapter, thetechniques andprocedures thatwereusedin theProjectdesigned toassess solarandwind energyaredescribed, This isdonesectionby sectionas it wasin Chapter4.

A. ORGANIZATION For maximumefficiencyof theoperation of theproject twocentersofctivitywere establishedat the MeteorologicalDepartment and theCenterforSolarRadiation andWind Calibration.

MeteorologicalDepartment TheMeteorologicalDepartment represented byMeteorological StudiesandResearchSub-Division, Studies andResearchDivision,was responsiblefordirecting theProject. This Sub-Divisionconsistsof threemeteorologists and twometeorologicalobservers. The senior levelmeteorologist,Chiefofthe MeteorologicalStudies andResearchSub-Division,wasdesignated as theProject Director.

Centerfor SolarRadiationandWindCalibration The Centerwasestablishedat the CalibrationSub-Division,InstrumentalDivision, BangNa MeteorologicalOffice. Itislocatedabout 10 kmfromMETHead Office. TheCenterwas assignedthe responsibilities of: " Measurementsof radiationand windat the Center;" Calibration of radiationand wind instruments; and* Maintenanceof equipment.The chiefengineerof the Sub-Divisionwasassignedas the supervisorof the Center. SIA personswerehired onatemporary basisas assistantmeteorologistsand assistantengineers to helptheengineeroperatethe Center.

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B. ADDITIONALMEASUREMENTS

Considerableeffortswereexpended indeterminingthe availability andsuitability ofrecording, processingandsensingequipment for the EnergyAssessmentProgramin Thailand. Resultsof thisworkledto the detailedspecificationof equipmentandinstrumentation. Allof the equipmentandinstrumentationwas shippedto Charlottesville,Virginia where itwas assembledand testedby Dr.Garstang,consultant of the Project.

Programmingof thedata loggers wascarriedout, alsobyDr. Garstang, forsolar radiation andwindmeasurementsfor applicationsat theSolar and Wind Calibration Centerand for fielddeployment. Similarly,programswere writtenand tested fordataretrievaland interpretation. Specialprograms werewrittento yieldinformation onthe solarand windpowerpotentialin formats whichwerequickto retrieveand easy tointerpret. Computer programtapes and listingswereprovidedtogetherwithinstructionand maintenancemanualsandtools for theequipmentandinstrumentation.

SolarRadiation Following the requirementsgiven inChapter4,additionalmeasurements

were takenon direct radiation, globalradiationanddiffuseradiation. Direct radiationTheinstrument formeasuringdirectradiationisEppleyNormal

IncidencePyrheliometer (NIP). Theinstrumentwasattached toan electrically drivenequatorialmountand recordedon acassettetape recordercontrolled by adata logger.

Global radiationTheEppleyPrecision SpectralPyranometer (PSP)recordedonatape

recorderanddataloggerthe same as theNIP. Diffuse radiationThe EppleyPrecision SpectralPyranometer (PSP)wasmountedwitha

shadowbandrecording on the samesystemas theNIP andPSP above.

WindThe additionalmeasurements forwind arewind speedand direction

andmobiletower.

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Wind speed and directionWind speed andwinddirectionaremeasuredbyMET- OneWind SpeedSensorand MET- OneWindDirection Sensorof CampbellScientific, Inc.The measured datawere recordedon acassettetape recordercontrolled by data logger. Profile measurementsProfilemeasurementswerenotapprovedbyUSAID,soit was not included intheoperation. Mobile towerAmobiletowerwas designedby Dr. Garstangand constructedunderthesupervisionof theproject engineerand the InstrumentsDivisionworkshop.Themobile towerextends to 10 mand canbe used at lowerheights. Itisfurtherdesigned to accommodatetemperature as wellaswind speedmeasurements at two levels. Themobile towermaybe usedwithasinglemeasurement (windspeed)tosurveynewsites or obtainsitedetailsorit maybe used tointercomparewithexistingsites at thesite anemometerlevel (3.1m)and simultaneouslyrecordwind and temperature at boththe 3.1mand 10 mlevels. Thepurposehere is to obtaininformationon theheightdependence of thewindandtodevelopappropriate heightcorrections to the lowlevel windmeasurements.

C. MEASUREMENTSMETHODS

Measurements of solarradiation andwind are done at theCenter andin the field.

Center for SolarRadiation andWindCalibration The Centermakesobservation forboth solarradiationandwind. Theobjectives of theobservation arefordatacollectionandcalibrationof

instruments. Solar radiationSolarradiationmeasurementsat theCenterare direct radiation,globalradiationand diffuseradiation Theseinstrumentswereinstalled on the roofofthe CalibrationCenter to serve as radiationreference standardinstruments.

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" Direct radiation An EppleyNormalIncidence Pyrheliometer (NIP)attachedto an electrically drivenequatorialmountandrecordingon acassettetape recordercontrolled byadataloggerwas installed.

* Globalradiation AnEppleyPrecisionSpectralPyranometer recorded on the same taperecorderand dataloggeras theNIP.

" DiffuseRadiation An EppleyPrecision SpectralPyranometer (PSP)wasmounted withashadowband,recordingon the samesystemas the NIP andPSPabove.

In additiontothese three instruments, twoexistingAngstrom Pyrheliometers of MET,servingas National StandardPyrheliometers,are alsoused fordirect radiationmeasurement. indWindspeed and direction systemswere installed to serveas areference for field units. Exposureof thissystemonthe roofof theCalibration Centerprecludes its useasavalidmeasurement of ambientwind. The

system,however,can serveas an intercomparisonreferencetoafield unitplacednext to it. This windsystemwith its data loggeralso servesas the unit on themobiletower.

SolarRadiationMeasurements Themeasurements of solarradiationwere takenin twosteps as described in Chapter4. They were sitesurvey and installation. Site surveyThesitesurveysforsolar radiationmeasurementswereperformedas follows:

Place Parameter Date ChiangMai globalradiation 7April 1983 Songkhla globalradiation 23May1983 ChiangMai netradiation 19 January1984 UbonRatchathani global radiation 16-17 May 1934 Khon Kaen globalradiation 31 May1984

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InstaZlationInstallationof solarradiation instrumentsweremadeas follows:

PlaceCenter forSolar andWindCalibration,BangNa

NorthernRegionalWeatherForecastingCenter, ChiangMai North-EasternRegionalWeatherForecastingCenter, Ubon SouthernRegionalWeatherForecastingCenter,HadYai, Songkhla Khon KaenSuratThani

WindMeasurement

Instruments - Eppleyblackandwhitepyranometer. - Eppleyprecisionspectrum pyranometerwithshadowband.- Eppley normalincidencepyrhelio

meterwithsolar tracker.- Eppley blackandwhitepyranometer.

- Eppleyblack andwhitepyranometer.

- Eppley blackandwhitepyranometer.

- Eppleyblackandwhitepyranometer. - Eppleyblackanduhitepyranometer.

Themeasurementsof windaredoneasdescribeatn Chapter 4: site surveyandinstallation.

Site surveyThe site surveys forwindmeasurementweredoneas follows:

PlaceBangkokPilot StationPattayaNakorn SawanPhuketUbonRatchathaniKhonKaenTak

79

Date 22March 1983 26April 1983 9May 1983

18-19June1983 16-17May 1984

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The instrumentsaboveserve asNational Standard Instruments for solarradiationmeasurement andwereusedforcalibrationofsolarradiation instruments (thermopile)attheCenter. ThethreeEppleyblackand white pyranometersserveas the secondarystandard forfield calibrationof bimetallic-type solarinstruments.

Wind tunnelAn existingclosed circuitwind tunnelwas renovatedby theprojectengineer andInstrument Divisionworkshop undersupervisionof Dr. Garstang.Calibration instrumentation (pilottube andmanometer)werepurchased from themanufacturer in theUSA. Other facilitiesThe Solar RadiationandWindCalibration Center isalsoequippedwithautomaticwind speedandwinddirection sensors asmentionedpreviously.Four small-sizewindsensor units wereavailable at theCenter to be used as spareequipment. Inaddition, thereweretwo Hewlett-Packard HP-85 micro-computers at the Center. Oneof themwasusedas adatarecoveryunitto transfer recorded dataoncassette tape intoacomputercartridge or to print-out hardcopy. Theotherwas used tomake calculations for the calibrationof instruments.

SolarRadiationInstruments In orderto havecontinuousand reliable data,instrumentswere calibratedandmaintained. MaintenanceMaintenanceof solarradiationinstruments at BangNa, ChiangMaiand Had Yaiwas accomplishedas follows:

Station Time BangNa Continuously Chiang Mai 1. 6-10 June 1983 2. 27 July1983 3. 24-27October 1983 4. 12-13November 1983 5. 7-9 December 1983 6, 22-24 February 1984 7. 13-14May 1984 8. 12-13June1984

9. 6-13August 1984

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StationHadYai

Roi-Et (MET)NongKhai (NEA)UdornThani

Calibration

Time 1. 12August 1983 2. 1-2 September1983 3. 30 September1983 4. 7-19November 1983 5. 9December 1983 6. 14January 1984 7. 5February 1984 8. 22 May1984

27 January1984 26 July1983 6April1984

Calibrationof solar radiationinstrumentswasperformed at the Center for SolarRadiationandWindCalibration andinthefield. At the Center, the calibrationof solar radiationinstruments wasas follows:

Calibration atthe. Center Instrument

1. Kipp&ZonenPyranometer- NEA(6)

- EGAT (2)

- ChiangMaiUniv. (1)- KMIT (1)

2. RimcoPyranometer - Agrometeorological

Division,MET(10)3. Actinometers

- ObservationDivision,MET (1)

Date

15February1983 (1) 30 May1983 (2)1July1983 (1)22May 1984 (2)16 January1984 (1)4April1984 (1)2February 19843April 1984

February1983 (6) 12 June 1983 (4)

24 June 1983

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Thecalibration of solarinstrumentsin the fieldwasperformedas follows:

PlaceLoei (NEA)UdornThani (NEA)NongKhai (NEA)Mukdahan (NEA)ChiangRai (NEA)Ko Samui (NEA)

Wind Instruments

Calibrationin thefield(BimetallicPyranometer)

Date8Mar83, 16 Feb 84

12 Apr83, 24Mar8419May83, 28 Apr8412 Oct 83, 24 Jun844May83, 12 May 8416Jun83

As wellas solarradiationinstruments,wind instrumentsweremaintained and calibrated for thepurposeof continuityand reliability of data. MaintenanceThe maintenance ofwind instrumentswap performedat the following stations:

Place1. BangNa2. NakornSawan

3. Rayong

Date Continuously 1. 27-28Nov 83 2. 21-22 Feb 84 3.4.5.1.2.3.4.5.6.7.8.

83

16 May 8417 Jun84

Aug 8419-20Aug 83

16 Sep83 19-20 Oct 83

18 Jan84 14Mar 84 17-18Apr 84 22-25May84

Aug84


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RegionalCalibration NationalStandardPyheliometerswerecalibratedwithWMORegional

RadiationCenter,CRISRO,DivisionofAtmospheric Research,Australia duringMarch6-25, 1984.

E. DATAPROCESSING

Most of the data-processingwasdone followingDr. Garstang'sdesign as described inChapter4. Modelcalculationwas excludedfromtheprogram owingto itsexpense. TheMET did nothavethehuman resourcesand facilities tohandlethe processing of data,so KMITandDr. Exellof AIT were hired todo the dataprocessing. Details of thedataprocessing processareprovidedin Chapter6.

F. TRAINING

Trainingcanbe divided intoin-country andoverseastraining.

In-CountryTraining In-country trainingwas doneatMET andAIT. Eachprogramwas

differentinnatureasmentioned in Chapter4. Meteorologica DepartmentTwentythree personsattended the trainingcourseentitled"Solar andWindResources", fromDecember 12, 1983to January6,1984. Lectures were givenby Dr.MichaelGarstang. Participantsof the trainingwere: fromMET (15), fromtheDepartment of Science Servie (1), fromKMIT (2), fromtheThailandInstitute of Scientific andTechnical Research (1), from theElectricityGenerating Authority of Thailand (11), andfromtheNEA (3). Inadditionto theseparticipants, observers fromMET,KMIT,andAITalso attendedthe training. Asian Institute of TechnologyTwo officials fromMETwere trainedat AITduringDecember 1983-April1984. One attendedcoursesatthe EnergyTechnology Division; the otherattendedcoursesat the ComputerApplicationDivision.

OverseasTraining All overseas trainingwascancelled due toadelay in correspondence betweenDTECandinstitutions intheUSA.

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G. BUDGET

Thetotalexpenditureof theprojectwasapproximatedtobe $6,457,835 fromtheUSAIDand$277,231 fromtheRTG.

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Chapter 6

AnalysisofResults


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ANALYSIS OF RESULTSTheanalysisofsolar radiationandwind ener

Documents

Solar and Wind Assessment in Thailand