Repetition
i i
Werner Weiss
AEE - Institute for Sustainable Technologies
A-8200 Gleisdorf, Feldgasse 2
AUSTRIA
Achievements - 2009
B
Total Capacity in Operation [GWel ], [GWth] and Produced Energy [TWhel], [TWhth], 2008
340.0
350
325
Total capacity in operation [GW] 2009
300
heat power
275
P d
Produced
d Energy
E
[TWh] 2009
250
225
200
189.0
175
150
158.0
137.0
125
100
83.0
75
50
25
0
11.0
Solar
S
l Thermal
Th
l
Heat
Wi d Power
Wind
P
Geothermal
G th
l
Power
23.0 24.0
Ph t
Photovoltaic
lt i
0.7 1.8
0.5 0.7
Solar
S l Thermal
Th
l
Power
Ocean Tidal
O
Tid l
Power
Distribution of Collectors
Unglazed Collector
12.4%
Air collector
0.8%
-4.5%
+4.5%
Evacuated tube
54 2%
54.2%
Flat-plate
Flat
plate
32.6%
0%
Solar Heat Worldwide - 2008
Installed Capacity [MWth]
15,000
12,000
10,500
glazed
evacuated tube
80,32 9.7
13,500
unglazed
9,000
7,500
6,000
4,500
3,000
1,500
0
China
United
St t
States
Germany
Turkey
Australia
Japan
Brazil
Austria
Greece
Israel
Installations by Economic Region 2008
Flat--plate and Evacuated Collectors
Flat
Central
C
t l + South
S th America
A
i
1.7%
Europe
14.5%
China
78.9%
Others
6.1%
Asia
1.7%
Middle East
0.8%
Australia + New Zealand
0.8%
United States + Canada
0.6%
Japan
0.5%
Africa
0.3%
Annually installed capacity of flat-plate
and evacuated tube collectors
Installed capacity
p y [[kWth/a/1,000
,
inh.]]
18.0
17.0
16.0
15 0
15.0
14.0
13.0
12.0
11 0
11.0
10.0
9.0
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
00
0.0
Middle East
Australia + New Zealand
Central and South America
Japan
Asia
2000
2001
2002
China
Europe
Africa
United States+Canada
2003
2004
2005
2006
2007
2008
Distribution of different solar thermal
systems by economic region
Thermosiphon Systems
Pumpe
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
United States
Europe
Australia
Japan
Brazil
China
Distribution by Application
World’s Top 8 Countries / Related to newly installed capacity in 2008
Source: Weiss, W., Mauthner, F.: Solar Heat Worldwide, IEA SHC 2010
Cooling Systems 2009
Source:www.greenchiller.eu.
Applications
Solar Water Heating Systems
G
Gravity
it driven
d i
systems
t
fsol = 70 – 90%
700 – 1000 kWh/kWth
Solar Water Heating Systems
Solar Water Heating Systems
Three different types of
evacuated tube collectors:
all-glass
U tube
U-tube
heat-pipe
Pumped SWH Systems
12
1
2
7
5
10
9
11
6
3
4
8
Small-scale Systems
y
for Hot Water Preparation
fsol = 80 – 90%
800 – 1000 kWh/m² collector area (Southern
Africa)
Combined SWH and Cooling
Solar Air Conditioning and Cooling
Source : Fraunhofer ISE, Solarnext
Solar Cooling System for the German BMVBW
Solar Collectors
for Cooling
Source: Jan Albers, IMBE, TU Berlin
Solar Combi Systems
y
for SFH
fsol = 50 – 90%
500 – 600 kWh/m² (Southern Africa)
Large-scale
Large
scale solar heating systems
Solar District Heating
S l yields:
Solar
i ld 400 – 460 kWh/m².a
kWh/ ²
Marstal Denmark 12.8
Marstal,
12 8 MWth (18.365m
(18 365m2)
Tyras Dairy, Trikala, Greece
Textile Industry Hangzhou China 13000㎡ (9 MWth)
SEA WATER DESALINATION
Pilot System Spain, CIEMAT, INETI
252 CPC AO SOL (499 m²)
SOLAR RADIATION - 1
SOLAR CONSTANT
1360 W/m²
GLOBAL IRRADIATION
800 - 1000 W/m²
SOLAR RADIATION - 2
Solar irradiance [W/m²]
Diffuse fraction [%]
Clear,, blue sky
y
Scattered clouds
Overcast sky
y



600 - 1000
200 - 400
50 - 150
10 - 20
20 - 80
80 - 100
Global irradiance and diffuse fraction, depending on the
cloud conditions
SOLAR RADIATION - 7
Jan
Feb
Mar
April
May
June
July
Aug
Sep
Oct
Nov
Dec
Year
Lat
Vienna, Austria
25.2
43
81.4
118.9 149.8 160.7 164.9 139.7 100.6
59.8
26.3
19.9
1090
48.2 N
Kampala UG
Kampala,
174
164
170
153
151
142
141
151
155
163
154
164
1882
00 2 N
00.2
Johannesburg
215
185
183
144
135
119
132
158
189
200
197
218
2076
26.1 S
Average
g monthly
y and yyearly
y values of g
global solar radiation on a horizontal surface in kWh/m²
Depending on the geographic location the yearly global
insolation on a horizontal surface may vary between
1000 and 2200 kWh/m2
ANGLE OF TILT
Latitude
[degree]
50 N
40 N
30 N
20 N
15 N
10 N
Equator = 0
10 S
15 S
20 S
30 S
40 S
50 S
Best collector tilt in:
June
26.5
16 5
16.5
6.5
3.5
8.5
13 5
13.5
23.5
33.5
38.5
43.5
53.5
63.5
73.5
Orientation
S
S
S
N
N
N
N
N
N
N
N
N
N
Sept./March
50
40
30
20
15
10
0
10
15
20
30
40
50
Orientation
S
S
S
S
S
S
N
N
N
N
N
N
December
73.5
63 5
63.5
53.5
43.5
38.5
33 5
33.5
23.5
13.5
8.5
3.5
6.5
16.5
26.5
Orientation
S
S
S
S
S
S
S
S
S
S
N
N
N
Maputo: Latitude -25.9
Cape Town: Latitude - 34
As a general rule, the optimum angle of tilt is equal to the degree of latitude of the site
TYPES OF COLLECTORS
FLAT-PLATE
FLAT
PLATE COLLECTOR
Transparent
cover
Insulation
Absorber plate
Tubes
Source: Consolar
Evacuated Tube Collectors – Heat Pipe
p
Absorber Material
Aluminum or Copper?
37%
63%
Aluminum
Copper
Source: Sonne, Wind und Wärme, 2009
ABSORBER COATING
Selective coating:
0   < 0.2,  > 0.9
Partially selective coating:
0.2   < 0.5,  > 0.9
Non selective coating:
0.5   < 1.0,  > 0.9
Plain copper
pp
black p
paint
galvanic coating
g
g
p y
physical
vapour
p
deposition or sputtering
COLLECTOR MATERIALS
?
ABSORBER MATERIALS
THERMAL CONDUCTIVITY
absorber material
thermal conductivity
[W/mK]
steel
50
aluminium
210
copper
pp
380
TRANSPARENT COVER MATERIALS
cover
thickness
[mm]
weight
[kg/m²]
solar transmittance
Standard g
glass *))
4
10
0.84
Standard glass, tempered
4
10
0.84
Iron free glass, tempered
4
10
0.91
Antireflective coated glass
4
10
0.95
PMMA, ducted plate
16
5.0
0.77
PMMA, double ducted plate
16
5.6
0.72
*) danger of breaking determined by high collector temperatures
Sola
ar trans
smission
TRANSPARENT COVER MATERIALS
AR coated
Uncoated
Incident angle
(42)
Physical Processes inside a Flat-Plate
Flat Plate Collector
heat loss through
the pane of glass
reflection
on absorber
reflection on the
pane of glass
occurrence
of solar radiation
heat loss through the
rear and side walls
Losses of a basic Flat-plate
Flat plate Collector
Source: Source: Wagner & Co.
Characteristic Values of Flat-plate and
E
Evacuated
t d Tube
T b Collectors
C ll t
Qcoll is the energy collected per unit collector area per unit time
FR is the collector’s heat removal factor
τ is the transmittance of the cover
α isi the
h shortwave
h
absorptivity
b
i i off the
h absorber
b b
G is the global incident solar radiation on the collector
UL is the overall heat loss coefficient of the collector
ΔT is the temperature differential between the heat transfer fluid
entering the collector and the ambient temperature outside the
collector.
Collector Efficiency
y Curve
(tm – ta)/G [Km²/W]
Collector Efficiency

Nutzenergi
useful
energy e
eingesetzt
eEnergie
solar energy
(t m  t a )
(t m  t a )²
   0  a1 
 a2 
G
G
Collector Efficiency
s. T-Sol Collector data
Collector efficiency
y curve
Optical Losses
0,8
0,7
0,6
Thermal Losses
0,5
eta
0,4
0,3
Useful Energy
gy
0,2
0,1
Stagnation Point
0
0
0,04
0,08
(TKm-TA) / GT [Km²/W]
0,12
0,16
Efficiency of different collector types (calc)
Evacuated Tube Collector
Selective Flat-plate Collector
Uncovered Absorber
Simple Flat-plate Collector
(tm – ta)/G [Km²/W]
Capacity of a Water Storage (calc)
THERMOSYPHON SYSTEMS
insulation
float valve
overflow
pipe
hot water
outlet
cold water inlet
collector
Hot water storage
for a thermosyphon system
1 Coating
2 Insulation
3 Steel tank
4 Enamel coating
5 Electric heating element
6 Sacrificial anode
7 Thermostat
8 Double Jacket Heat Exchanger
9. Cold water inlet
10. Hot water to user
11. Heat exchanger inlet
12. Heat exchanger outlet
Source: Chromagen
13. Heat Exchanger Safety Valve
Domestic Hot Water Tank
Hot water tanks with stratification devices
Sources from left to right: Solarklar, TiSun and Solvis