Small and larger scale
Solar Thermal
for northern climates
Chris Bales
Solar Energy Research Center SERC, Högskolan Dalarna
Midnight Sun Seminar 2012, 23rd Aug 2012
Contents
• Background
• Fundamentals
• System types for northern climates
• Current research and the future
Midnight Sun Seminar 2012, 23rd Aug 2012
My background…
• Born in Kenya (50 km from equator)
• Married to someone born 50 km from Arctic Circle
• Educated in England
• Engineering degree in electrical sciences
• 5 years at British Antarctic Survey
• Weather observer and technician
• 2 years at New Zealand Meteorological Service
• Working with climate databases
• 20 years at Högskolan Dalarna
• Started as technician….now associate professor
• Specialist in solar thermal, heat storage, system
simulations
• Mostly international projects
Midnight Sun Seminar 2012, 23rd Aug 2012
Campus Lugnet
Humanities and Media
Studies
Health and Social
Studies
2 600 students
Campus
Framtidsdalen
Technology and
Business Studies
1 900 students
Bergsskolan Filipstad
@ Web-Based
Distance Education
Falun
Borlänge
Högskolan Dalarna
Midnight Sun Seminar 2012, 23rd Aug 2012
Student Numbers 2010
• 18 000 students
• 7 256 full-time students
• 11 800 distance students
• 1141 degrees conferred
Now over half the students
are distance students
Midnight Sun Seminar 2012, 23rd Aug 2012 6
SERC – Solar Energy Research Center
• Founded 1984, grown steadily since
• 23 staff engaged in R&D and education:
4 Professors (part-time), 9 PhD, 8 PhD
students,
(in process recruiting 1 more professor)
technician, 1-3 trainees, guest researchers
• Multidisciplinary research: technology and social sciences
• Variety of educational programmes
• Research turnover >1,5 M€/year
www.serc.se
Energy and environmental technology
Midnight Sun Seminar 2012, 23rd Aug 2012 7
SERC –Research Areas
Solar and biomass heating systems
Solar thermal systems and thermal storage
Solution vessel
Water vessel
Reactor
Condensor /
Evaporator
• Conversion of electrically heated
homes
• Development of solar and biomass
heating systems
• Lab and field measurements
• Modeling and simulation
• Minimising primary energy use and
harmful emissions
• Advanced thermal storage
• Chemical heat pumps
• Solar heating and cooling
• Seasonal storage of heat
Midnight Sun Seminar 2012, 23rd Aug 2012 8
SERC –Research Areas
Energy use and societal processes
Small scale electricity generation
Social anthropology+Political
science+Technology
• Conversion of heating systems
• Installers and other market players
• Home owners choice of heating system
• Implementation of national energy policy
• PV grid connected systems
• PV/wind hybrid stand-alone systems
• Small scale cogeneration
Energy and buildings
• Passive houses of Massive wood
• Thermal storage in buildings
• Steel claddings for reduced heating and
cooling demand (Prelaq Energy)
Midnight Sun Seminar 2012, 23rd Aug 2012 9
SERC –Education
• One year International Master program
in solar engineering – ESES (European
Solar Engineering School) www.eses.org
• Collaboration in 2 year solar and
biomass technician programme
• 2 year energy technician programme
(start 2008)
• Responsible for solar specialisation of
KTH’s 2 year master program
• Participation in development of ”nordic”
master in biomass and solar
(värmeekom)
Midnight Sun Seminar 2012, 23rd Aug 2012
Källa: PVGIS © European Communities, 2001-2006
Solar Radiation in Europe
kWh/m2/a %
Pori 1129 100
Hamburg 1104 98
Graz 1321 117
Sevilla 1947 172
Irradiation on an optimally tilted plane [kWh/m2/a]
Midnight Sun Seminar 2012, 23rd Aug 2012 11
0
50
100
150
200
250
Jan
Feb Mar
Apr
May
Jun
Jul
Aug
Sep O
ctNov
Dec
Mo
nth
ly irr
ad
iati
on
[kW
h/m
2]
Pori
Hamburg
Graz
Sevilla
Irradiation Potential
The uneven yearly distribution of
irradiation presents a problem in the
Nordic Countries:
Data: European Comission PVGIS, http://re.jrc.ec.europa.eu/pvgis/
Irradiation on an optimally tilted plane.
The energy demand is highest when
available irradiation is lowest.
For solar fractions > ~25% we
need seasonal storage of energy
from summer to winter (space heating+DHW systems)
Midnight Sun Seminar 2012, 23rd Aug 2012
The solar thermal ”pinch”
0
5 0 0
1 0 0 0
1 5 0 0
2 0 0 0
2 5 0 0
3 0 0 0
Ja n F e b M a r A p r M a y Ju n Ju l A u g S e p O c t N o v D e c
(kW h )
E xcess irrad ia tion E xcess consum p tion
Usab le so la r ene rgy Irrad ia tion
To ta l consum p tion
3 0 0 0
2 5 0 0
2 0 0 0
1 5 0 0
1 0 0 0
5 0 0
0
1
2
3
1
Midnight Sun Seminar 2012, 23rd Aug 2012
Don’t forget – radiation varies from year to year!
Data for horisontal radiation – lower for higher latitudes
+/- 10% !!
Midnight Sun Seminar 2012, 23rd Aug 2012
Temperature Important with Solar Thermal !
Figure: Lennart Molin
Midnight Sun Seminar 2012, 23rd Aug 2012
Classification of systems
• Classification by use (load)
• DHW systems
• Combisystems
• Pool systems
• Process heat
• Solar cooling
• ….
• Domestic systems
• Multifamily houses
• District heating (large scale)
Traditional Scandinavian market:
domestic solar combisystems
Midnight Sun Seminar 2012, 23rd Aug 2012
Pumped Solar Combisystem
Source: Solenetek AB
Auxiliar heat from:
Biomass boiler/stove
Electricity
Heat pump
Gas/oil boiler
….
Midnight Sun Seminar 2012, 23rd Aug 2012
Small systems bought , larger systems custom built
• Small systems sized and installed by salesman/installer
• Buyer often gets quotes from several suppliers, but not
always
• Often ”standard” packages even though some
customisation is possible
• Larger systems designed by engineers
• Every system unique
• Engineers size system (simulation tools) and then do
detailed design
• Owner often not same as user
• Greater requirements on documentation and professionalism
• Often requirement for public call for tenders
Midnight Sun Seminar 2012, 23rd Aug 2012
Trends: Full integration – or greater flexibility
More integration + System optimisation
+ Quicker installation
+ Smaller risk for faulty installation
+ Uses less space
- Less flexibility
- Everything must be bought at one time
Flexible systems + Can easily be changed
over time
+ Not everything has to be bought at same time
+ Not dependent on just one supplier
- More difficult to optimise (several different controllers)
- Greater risk for faulty installation
- Uses more space
Midnight Sun Seminar 2012, 23rd Aug 2012
Integrated DHW systems
Standard size (60 x 60 cm) for tank unit
Figures: Vaillant GmBH
Midnight Sun Seminar 2012, 23rd Aug 2012
Integrated boiler and tank
Oil or gas boiler in tank
(Germany – Solvis)
Source: Stocksbro energi(biosolpanna)
Pellet boiler in tank -
biosolpannan (Sweden –
Stocksbro energi).
Midnight Sun Seminar 2012, 23rd Aug 2012
Solar and biomass logical for Scandinavia
• Most popular form of system
• Many advantages
• Much work been done with them
• Building regulations a hinder in Sweden
• Retrofit the biggest market
Midnight Sun Seminar 2012, 23rd Aug 2012
Handbook with all latest research results
• In Swedish – suitable for both consultants and installers
Tomas Persson
Researcher at SERC
Lars Andrén
Author, chairman Swedish
solar energy association
Midnight Sun Seminar 2012, 23rd Aug 2012
Are building regulations a barrier for solar + biomass?
Biomass
η=80%
Heat load
max
13 000 kWh
110 kWh/m2 55 kWh/m2 55 kWh/m2
District heat
η=100%
Heat load
max
16 500 kWh
110 kWh/m2
Exhaust air heat
pump
Heat load
max
20 000 kWh
Ground heat
pump
COP=3
Heat load
max
25 000 kWh
Bought energy limited by
building regulations !
Different for electricity
Electrically
heated houses Other heat source
90 kWh/m2
13 500 kWh 10 800 kWh
Midnight Sun Seminar 2012, 23rd Aug 2012
Costs for different heating systems….
Kiruna, standardhus
0 5000 10000 15000 20000 25000 30000 35000 40000
Passiv+Sol+FTX
Pellet
Pellet+FTX
Pellet+Sol+FTX
FVP
FVP kond.
FVP kond+Sol
FVP+JV
BV
BV+FTX
Fjärrvärme
Fjärrvärme+FTX
Kapitalkostnad Underhållskostnad Energikostnad
For houses being built now
Midnight Sun Seminar 2012, 23rd Aug 2012
Small scale solar and pellet system
Figure: Lennart Molin
Pellet stove and solar hot
water system separately
– suitable for houses with
electrical panel heaters
Combined system for
houses with water
distribution system
Midnight Sun Seminar 2012, 23rd Aug 2012
24 134
19 669 19 768 19 263 18 822 17 990 17 62715 750
305
1 012 350 397 387376 440
383
0
2 481 4 0223 789 3 978
3 932 4 604
4 176
0
5 000
10 000
15 000
20 000
25 000
Referens
(63%)
73% 79% 80% 82% 86% 87% 97%
Systemeffektivitet, köpt energi
Årl
ig e
nerg
itill
förs
el (k
Wh)
Sol
El
Pellets
Last
16 200 kWh/år
A B C ED F G
Solar and pellet systems – much better than pellet only
Midnight Sun Seminar 2012, 23rd Aug 2012
Turn boiler/stove off during the summer
Figure: Lennart Molin
Also best for oil and gas
boilers
Midnight Sun Seminar 2012, 23rd Aug 2012
Solar and heat pump – many systems !!
• 70 commercial systems found in EU
• Many different designs
Midnight Sun Seminar 2012, 23rd Aug 2012
Common Features for the two Technologies
• Both solar collectors and heat pumps
use electricity to make „free“ energy
available for hot water and space heat
• Both have decreasing efficiency with
increasing supply temperature
• Both have relatively high capital costs
and lower running costs compared to
conventional heating systems
• Both use thermal storage in systems
• The „free“ resource varies with the
seasons
HP
Midnight Sun Seminar 2012, 23rd Aug 2012
Several Unanswered Questions !
• How can the systems be compared ?
• Which systems are good ?
• How can they be tested ?
• Can they be cost effective ?…….
IEA-SHC Task 44 will try to answer these !
EU project MacSheep is trying to develop better systems
Midnight Sun Seminar 2012, 23rd Aug 2012
Quelle
: W
agner
& C
Oo
462 kWth; 660 m²
Multifamily houses – renovation key
Midnight Sun Seminar 2012, 23rd Aug 2012
Solar and district heat
• Centralised large systems
• Decentralised that feed into network
• Decentralised that take out heat from network
• Not very common apart from Denmark boom
Midnight Sun Seminar 2012, 23rd Aug 2012
Large Centralised systems
Källa: www.solar-district-heating.eu
• Often ground mounted collectors
• Sweden and Denmark leaders
• Germany and Austria also (new system in Lilleström)
• Normally relatively low solar fraction
• Scale effects reduce costs
Midnight Sun Seminar 2012, 23rd Aug 2012
Large Systems 2009
Källa: J-O Dalenbäck
Midnight Sun Seminar 2012, 23rd Aug 2012
Example Strandby (DK) - 2008
• 8.000 m2 Arcon collector (18% solar fraction)
• 2x1.500 m3 steel tanks
• Natural gas CHP (+ abs. Heat pump)
Källa: www.solar-district-heating.eu
Midnight Sun Seminar 2012, 23rd Aug 2012
Strandby - costs
Källa: www.solar-district-heating.eu – success factors
• 2.900 kr/m2 incl. all costs
• 2.350 kr/m2 after subsidies
Midnight Sun Seminar 2012, 23rd Aug 2012
Decentralise feeding grid – example (2009)
• Vislanda – Alvesta energi
• 350 m2 in large roof integrated modules (~10% solar fraction)
• Prefabricated connection unit
Källa: www.solar-district-heating.eu – success factors
Midnight Sun Seminar 2012, 23rd Aug 2012
Vislanda (2)
• 4.600 kr/m2 incl. all costs
• 2.450 kr/m2 after subsidies and ”roof replacement” costs
• Same as Danish larger system
• Economy dependent on what utility pays!
Källa: www.solar-district-heating.eu – success factors
Midnight Sun Seminar 2012, 23rd Aug 2012
Decentralised – replaces bought energy
• Simple to add to existing houses with district heating
• Utilities often not positive to it
• 7.000 kr/m2 incl. all costs
• But replaces bought energy
Midnight Sun Seminar 2012, 23rd Aug 2012
Danish Large Scale Systems
Midnight Sun Seminar 2012, 23rd Aug 2012
Midnight Sun Seminar 2012, 23rd Aug 2012
Demonstration System – multisource RE
Seasonal solar storage in combination with other heat sources – mostly heat pump
www.iea.shc.org/task45
Midnight Sun Seminar 2012, 23rd Aug 2012
Current Research and the Future
Solar thermal;
278
Buildings and cities; 126
PV & PV
systems; 91
Solar Thermal Power; 56
Radiation &
resource forecasting; 64
Other; 148
ISES World Congress 2011 Papers
Collectors and PVT; 51
Storage; 41
Solar
cooling; 40
Testing and simulation; 40
Industrial
applications; 27
Domestic hot
water systems; 22
Solar + heat pump; 21
Other; 36
Solar Thermal Papers
Midnight Sun Seminar 2012, 23rd Aug 2012
Solar Collectors
• ”High” temperature (100 – 200°C) collectors for solar cooling or process heat
• IEA-SHC task in preparation
• + old www.iea-shc.org/task33
• Polymer collectors for domestic applications
• www.iea-shc.org/task39
Source : Aventa, Norway
Source : PSE, Germany
Midnight Sun Seminar 2012, 23rd Aug 2012
Storage
• The dream of seasonal storage on smaller scale
• Material and process development
• Closed and open systems
• Basic and applied research
www.iea-shc.org/task42
• Three new EU projects on seasonal storage
Source: J. van Berkel
Thank you for your attention
www.serc.se
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