Energy

Renewable Energy in Germany Solar thermal energy in Germany: market, technologies, perspectives Gerhard Stryi-Hipp Fraunhofer Institute for Solar Energy Systems ISE Mexico, 20 September 2011

Solar Thermal Energy: Underestimated Source of Power

Source: IEA-SHC Solar Heat Worldwide, Edition 2011, www.iea-shc.org

© Fraunhofer ISE 2011

Solar Thermal World Market 2009 – New Installed Collector Capacity

Quelle: IEA SHC-Programm, Solar Heat Worldwide, Edition 2011

© Fraunhofer ISE 2011

Development of the German Solar Thermal Market

© Fraunhofer ISE 2011

Flat Plate Collector - Construction  Typical high efficient aluminium framed flat plate collector Absorber from Copper or Aluminium, selective coated: high absorption of sunlight low emission of infrared-radiation Copper tubes ultrasonic or laser welded

Low iron solar glass = improved transparency Sometimes AR anti reflective coated

Aluminium profile Adapter plate

Insulation Aluminium back board

Connection tube Aluminium frame Insulation Source: GreenOneTec

© Fraunhofer ISE 2011

Flat Plate Collector - Construction  Typical high efficient wooden framed flat plate collector Aluminium profile Glass sealing

Selective coated absorber

Connection tube

Solar glass

Insulation

Adapter plate Wood frame

Collecting pipe

Wooden back board

Source: GreenOneTec

© Fraunhofer ISE 2011

Solar Domestic Hot Water System - Basics Solar radiation

Principles of a SDHW System

Hot drinking water outlet

 Collector is converting radiation into heat  Output (efficiency) depends on collector efficiency and inlet temperature, radiation intensity and heat transfer fluid flow rate  The lower the heat transfer fluid flow rate the higher the outlet Auxiliary heating via temperature!

Glazed solar collector Flat plate collector or Evacuated tube collector

Pumped solar circuit - Anti freeze heat transfer fluid - Controller - Pump - Safety (pressure) valves

© Fraunhofer ISE 2011

natural gas,  The lower the absorber oil, wood, temperature the higher district the collector efficiency! heating, electricity,  Heat must be stored … Solar heat store with two heat exchangers

Cold drinking water inlet

since solar supply and DHW demand patterns usually do not match

Thermosiphon Solar Domestic Hot Water Systems are mainly used in southern countries Typical system for Southern Europe: • Thermosiphon system • 2-4 m² collector area • 80-150 liter storage tank • Natural circulation

By natural convection: The added solar heat expands the heat transfer fluid, becomes lighter and rises to the storage tank above. Source: Schueco

© Fraunhofer ISE 2011

Typical Solar Thermal Combi-System for domestic hot water and space heating

Combi-store Main store contains heating water (buffer) Smaller Tank-in-Tank contains drinking water

© Fraunhofer ISE 2011

Space heating circuit (water system)

Typical Large Solar Thermal Systems

Collector Loop freeze protected

Collector inlet temperature must be as low as possible (store stratification!) -> high collector efficiency

© Fraunhofer ISE 2011

Solar Heat Store buffer water

Charge and discharge devices and strategy must lead to a good temperature stratification

Domestic Hot Water supply

Cold water supply must cool down the bottom of the buffer store via heat exchanger for a high solar collector efficiency

Large Solar Thermal Systems  For multi family homes, hotels, hospitals, nursing homes  Crucial: management of the different heat sources

Image: Solvis

© Fraunhofer ISE 2011

Image: Wagner & Co

Promising Technology Solar Assisted Cooling  (Solar) thermally driven cooling machines  Cooling demand and solar supply patterns match well  There are already more than 400 pilot systems installed in Europe  Small systems are under development Adsorption cooling machine

© Fraunhofer ISE 2011

Building: IHK Freiburg

Source: Fraunhofer ISE

Source: Viessmann

Building: Governmental Press Office Berlin

© Solites

Promising Application Solar District Heating - will play a big role in the future

Solar District Heating, Marstal, Denmark collector area 17,000 m²

© Fraunhofer ISE 2011

© Solites

Semi-detached houses in Neckarsulm, Germany

© Arcon

12,000 m³ seasonal storage, Friedrichshafen, Germany

Innovative Tools for Technology Development in Germany and Europe: Solar Thermal Technology Platforms Concept to Accelerate Technological Development

Researcher

Politicians

Solar Thermal Vision 2030 Which role will solar thermal energy play in the year 2030 and which technologies will be used?

R&D agenda Industry

Which R&D steps are necessary to let the vision become reality?

Realization Solar Thermal Research Agenda published in Dec 2008: www.rhc-platform.org

© Fraunhofer ISE 2011

Stimulation of new R&D programs, political advice, lobbying,...

Solar Thermal Vision 2030 of the Solar Thermal Technology Panel of the European Technology Platform on RHC 

New buildings: Active Solar House - 100% solar heated buildings will be the building standard

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Existing building stock: Solar Refurbishment - Solar refurbished buildings > 50% solar heated, will be the most cost effective way to refurbish the building stock

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Commercial + Agricultural Solar Applications - Solar thermal systems will cover process heating and cooling demands

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Solar district heating and cooling networks - will be widely solar assisted

Overall goal: ca. 50% of the low temperature needs (up to 250°C) will be provided by solar thermal © Fraunhofer ISE 2011

From SDHW only …..…… to 100% Solar Heated Houses SDHW solar domestic hot water heating 10%-20%

0%

10%

‘Solar Active House’ mainly heated by solar SDHW + space heating support (large share) 50% - - - - - - - - - - - - - - - - - - 100%

SDHW + space heating support 20%-30%

20%

30%

40%

50%

60%

70%

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90%

100%

Share of solar thermal energy in the heat demand of a building © Fraunhofer ISE 2011

Concept of Solar Heated Building

Solar Thermal Collectors 30m² - 60m²

Seasonal Heat Storage (Water) 6 – 10 m³ Solar Fraction (share of the overall heat demand): 60% - 70%

© Fraunhofer ISE 2011

Conclusions  Solar thermal technology is a well established technology in Germany  Solar thermal energy can cover up to 50% of the overall energy demand for heating and cooling in Germany  Solar thermal technology has still a great potential for technological development, R&D activities are increasing  German companies do have a huge experience in system technology and offering high quality components and products for solar thermal systems © Fraunhofer ISE 2011

Thank you for your attention! Contact Gerhard Stryi-Hipp [email protected]