CLIMATOLOGY OF SOLAR IRRADIANCE ON INCLINED SURFACES - I. FINAL REPORT

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• Publié par: EUROPEAN-COMMISSION
• Nombre de lectures: 17
• Langue: Serbian
• Poids de l'ouvrage: 3 Mo

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Commission of the European Communities
energy
CLIMATOLOGY OF SOLAR IRRADIANCE
ON INCLINED SURFACES - I
Blow-up from microfiche original Commission of the European Communities
energy
CLIMATOLOGY OF SOLAR IRRADIANCE
ON INCLINED SURFACES - I
W.H. Slob, D.E. Brethouwer, C. den Ouden
Technisch Physische Dienst TNO-TH - Delft
Contract No 294-77 ES NL
FINAL REPORT
Directorate-General for Research, Science and Education
1981 EUR 7316 EN Published by the
COMMISSION OF THE EUROPEAN COMMUNITIES
Directorate-General
Information Market and Innovation
Bâtiment Jean Monnet
LUXEMBOURG
LEGAL NOTICE
Neither the Commission of the European Communities nor any person
acting on behalf of the Commission is responsible for the use which might
be made of the following information
ECSC-EEC-EAEC, Brussels-Luxembourg TPD nummer 803.229 blad -0-
CONTENTS Page no.
SUMMARY 1
1. INTRODUCTION 3 ·
2. DESCRIPTION OF THE MEASURING FACILITY 4
4 2.1. Location
4 2.2. Instruments
4 2.2.1. Pyranometers
4 2.2.2. Pyrheliometers
5 2.2.3. Filters
5 2.2.4. Other measurements
5 2.3. Calibration and control
3. DATA REGISTRATION SYSTEM 15
4. PROCESSING OF DATA 15
45 5. RESULTS
45 5.1. Reference pyranometers
45 5.2. Filters
45 5.3. Albedo
6. COMPARISON OF SUNSHINE DURATION MEASURED WITH A CAMPBELL-
STOKES AND THE DIRECT SOLAR RADIATION MEASURED WITH A 48
PYRHELIOMETER
48 6.1. Introduction
48 6.2. Measurements
48 6.3. Threshold
6.4. Determination of the threshold 49
6.5. Conclusion 50
54 7. TURBIDITY FACTOR
8. COMPARISON OF CALCULATED AND MEASURED DIFFUSE SKY
IRRADIANCE ON CLEAR DAYS FOR SEVERAL ORIENTATIONS 58
8.1. Summary 58
59 8.2. Introduction
60 8.3. Calculation of the measured diffuse sky irradiance
8.4. Estimation of the diffuse sky irradiance on clear
61 days from 2 models.
8.5. Comparison of the calculated and measured daily sums
63 of diffuse radiation from the sky for 16 clear days TP D nummtr 803.229 blad -00-
page ne.
8.6. Comparison of the half-hourly calculated and measured
diffuse irradiances on the horizontal 64
8.7. Differences between the two models5
8.8. Conclusions 66
9. LITERATURE7 TPD nummer 803.229 b,ad ~'
SUMMARY
This report describes the results of the work carried out by the
Royal Netherlands Meteorological Institute (KNMI) under contract
no. 294.77 ES NL for the Commission of the European Communities
(DG XII) and for the Dutch Solar Energy Programme under contract
no. 3.1.1., 3.1.2. and 3.1.3.
The work has been done in close co-operation with the Institute of
Applied Physics TNO-TH (TPD).
In Cabauw (51.966 N, 4.93 E) in the Netherlands the following
input variables were measured from March 1979 till October 1979:
- The global solar irradiance, with Eppley pyranometers, on the
following orientations: . 90 east, south, west, north
. 67.5 south
. 45 east, south east, south, south west, west
. 22.5 south
. 0 horizontal
- The direct solar irradiance on a surface perpendicular to the
sunbeam with an Eppley pyrheliometer.
- The ground reflected solar irradiance with an Eppley pyranometer
in the inverted position.
The 6 minute averages of all these data have been recorded and
presented in this report in the form of hourly, daily ,and monthly
totals as well as in frequency distributions.
Moreover, an analysis of the results is presented.
A comparison between sunshine duration with a Campbell Stokes and
the direct solar radiation measured with a pyrheliometer is made.
Hourly turbidity factors (Linke) were calculated for hours with
2
direct solar radiation larger than 140 W/m .
For 16 clear days with average Linke turbidity factors between 2.5 and
7.0 the measured diffuse sky irradiance for 12 different orientations
was compared with the calculated irradiances from 2 models.
Both models have good results at Linke turbidity factors around 6.
For smaller turbidity factors the model given by Liebelt and Bodmann
shows good results on the vertical surfaces and the surfaces facing the
sun, but overestimates the irradiance on the horizontal surface.
The model given by Dogniaux underestimates at most of the orientations
but has good results on the horizontal surface. TPD
nummer 803.229 blad -2-
1. INTRODUCTION
This is the final report of the research work carried out by the
Royal Netherlands Meteorological Institute (KNMI) under contract
no. 294.77 ES NL for the Commission of the European Communities
(DG XII) and for the Dutch Solar Energy Programme under contract
no. 3.1.1., 3.1.2. and 3.1.3.
The work has been done in close co-operation with the Institute
of Applied Physics TNO-TH (TPD), which, being a sub-contractor
was responsible for measurements, data handling and presenting
of the measured solar radiation data.
This research work is part of the CEC-Solar Energy Programme
Project F: Solar Radiation Data Acquisition, action 3.2.,
calculation methods for radiation data on inclined surfaces and
action 4.2. special measurements, spectral measurements, turbidity
etc.
The main aim of this experimental work was to get better radiation
data on inclined surfaces in order to be able to do more accurate
calculations on the system performance of solar energy installations
in the future.
This report describes the experimental installation consisting of
12 pyranometers for the measurement of solar radiation coming from
different orientations on various inclined surfaces and 2 pyr-
heliometers for the measurement of direct solar radiation.
Moreover, the experimental installation was equipped with 3 other
pyranometers for measurement of albedo and solar radiation in
specific wavelength regions.
Furthermore the measurements carried out with these instruments
over a period from March 1979 - October 1979, are presented in the
form of hourly, daily and monthly totals as well as in frequency
distributions.
Finally an analysis of the results is presented.
A comparison between sunshine duration measured with a Campbell-
Stokes and the direct solar radiationd with a pyrheliometer
is made. TPD nummer 803.229 blad
Hourly turbidity factors were calculated for hours with direct
2
solar radiation larger than 140 W/m . TPD nummer 80 3.229 blad -4-
2. DESCRIPTION OF THE MEASURING FACILITY
2.1. Location
The measuring equipment is situated in open and plain grassland in
the immediate surroundings of a mast which registers meteorological
data for the KNMI (Royal Netherlands Meteorological Institute) at
Cabauw (20 km south-west of Utrecht).
The geographical coordinates are:
in latitude: 51.966 north,
in longitude: 4.933 east.
Direction south the view from the facility is completely unobstructed
and is formed by meadows and, at a distance of about 300 m, by a dyke
bordered with trees, (see picture 2.1.)
2.2. Instruments
2.2.1. Pyranometers
Onto a mast of about 4 ra length 12 pyranometers (Eppley, type PSP) have
been mounted under various angles (see picture 2.2. and table 2.1.)
By means of these pyranometers the global solar radiation on various
surfaces is determined.
The orientation of the pyranometers has been checked and the deviation
of the in table 1 mentioned positions was found to be smaller or
1 1°
equal to 1 .
In the adjacent meadow two more pyranometers have been placed.
One of them is placed in the horizontal plane and is equipped with a
shadowband for the determination of the diffuse radiation (see
picture 2. 3. )
Of the second meter the measuring side faces downward and is used
to determine the radiation reflected by the surface of the earth
(see picture 2.4.).
2.2.2. Py_rheliometers
With the aid of two pyrheliometers (Eppley, type NIP), placed on an
electrically operated solar tracker the direct solar radiation is
measured (see picture 2.5.).