Transcript Bez nadpisu

Experience from PV system performance
(including comparison of on-roof and façade
systems in Prague)
Vitezslav Benda, Zdenek Machacek
CTU Prague, Faculty of Electrical Engineering
In the year 2001, a 3kWp demonstration, on-grid connected
photovoltaic system has been built at the Czech Technical
University in Prague on the roof of the Faculty of Electrical
Engineering.
PV module field
+
-
+
-
Inverter SUNRISE MINI
~ 230 V
+ =
= 180 V
~
+
switchboard
grid
connection
SUNRISE
datalogger
display
unit
PC
radiation
temperature
datalogger
~ 230 V
In the year 2001, a 3kWp demonstration, on-grid connected
photovoltaic system has been built at the Czech Technical
University in Prague on the roof of the Faculty of Electrical
Engineering.
PV field 1
Inverter
SUNRISE
Shunt
=
~
Temperature
sensor
Radiation
sensor
Comp.
network
Ethernet
RJ45
Display
unit
RS 485
PV field 2
PC
=
~
Datalogger
FVS 2300E
PV field 3
RS 232
RS 422
=
~
Power
measuring
Converter
RS 422/RS232
Grid connection 230 V / 50 Hz
Installed peak power: 3320 Wp
Total module area:
26 m2
Number of modules: 30 (3 fields of 10)
Latitude:
Altitude:
50.07 °N
205 m
http://k313.feld.cvut.cz/solarsys/
Module type
Pmax (Wp)
Vpm (V)
Ipm (A)
VOC (V)
ISC (A)
hcell (%)
hmodule (%)
RADIX72-112
111,5
17,4
6,41
21,5
7,04
14,9
12,8
RADIX72-108
107,8
17,1
6,29
21,5
6,98
14,4
12,4
Parameters of PV modules at radiation power 1000W/m2, spectrum AM 1,5 and
temperature 25°C
PV field
Tilt angle
Module type
Pm (Wp)
1
45°
RADIX72-112
1120
2
variable
RADIX72-112
1120
3
90°
RADIX72-108
1080
Parameters of individual PV fields
Type of inverter
Sunrise Mini
Sunrise Micro
Input voltage
120 - 300 V
120 - 300 V
Nominal input voltage
170 V
170 V
Maximum input
voltage
350 V
350 V
Output voltage
230 V,+10/-15%
230 V,+10/-15%
Output frequency
50 Hz,+/-0,2 Hz
50 Hz,+/-0,2 Hz
Output nominal
current
4,4 A
3,2 A
Output nominal power
1000 W
750 W
Harmonic distortion
< 3%
< 5%
Maximum effectivity
93%
92%
Dark consumption
0W
0W
Parameters of Sunrise inverters
Ja
nu
a
M ry
ar
ch
M
a
Se J y
pt ul
e y
N m
ov be
em r
Ja be
nu r
a
M ry
ar
ch
M
a
Se J y
pt ul
e y
N m
ov be
em r
Ja be
nu r
a
M ry
ar
ch
M
a
Se J y
pt ul
e y
N m
ov be
em r
Ja be
nu r
a
M ry
ar
ch
M
a
Se J y
pt ul
e y
N m
ov be
em r
be
r
Average daily energy production (Wh)
A comparison of estimated and measured energy
production in period from January 2002 to December 2005
2002
2003
Estimation
2004
Measured
2005
14000
12000
10000
8000
6000
4000
2000
0
0
PV field 1
PV field 2
PV field 3
November
September
July
2004
May
March
January
November
September
July
2003
May
March
January
November
September
2002
July
May
March
January
November
September
6000
July
May
March
January
Average daily energy production (Wh)
Energy produced by individual PV fields in period from
January 2002 to December 2005
2005
5000
4000
3000
2000
1000
Temperature dependence of energy conversion efficiency
15,0
30,0
13
25,0
12,0
Efficiency
November
-5,0
October
September
PV field temperature (°C)
60
August
40
July
9,0
June
8
5,0
0,0
May
10,0
20
10,0
11,0
9
0
15,0
April
10
20,0
March
11
13,0
February
12
PV field temperature (°C)
Temperature
14,0
Efficiency (%)
Efficiency (%)
14
35,0
This gives the efficiency decrease of about 0.6% per 1K, which is higher than supposed
decrease of cell efficiency (about 0.4% per 1K).
It means that an increase of losses with increasing temperature in other parts of system
cannot be neglected.
August
January
Temperature distribution over the PV field areas
June, ambient temperature 32 °C
Tilt angle: 45°
roof
39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58
Tilt angle: 90°
facade
Temperature distribution over the PV field areas
December, ambient temperature -6 °C
roof
teplota (°C)
Output power (W)
Shadowing effect
900
800
700
600
500
400
300
200
100
0
8:00
9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00
PV field 1
PV field 2
PV field 1
PV field 2
Conclusions
• Facade PV system applications can produce about
66% of electrical energy produced by the roof (45°
tilted) one
• Efficiency of PV systems is strongly influenced by
temperature
• PV field constructions should allow an effective
cooling of PV modules