1. Solar Thermal District Heating
Freiburg-Gutleutmatten
Alexander Ripka
Axel Oliva
Local Renewables 2018
Freiburg i.Br.
25.10.2018

2. „Local Renewables 2018“ Freiburg i.Br., 25.10.2018
 Project Partners
 Concept of Heating Supply
 Efficient Management Strategies
 Résumé
 Study Visit
1
Agenda

3. „Local Renewables 2018“ Freiburg i.Br., 25.10.2018
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Project Partners
City of Freiburg i. Br.
 Development and administration
Fraunhofer Institute for Solar Energy
Systems
 Research and support
badenovaWÄRMEPLUS GmbH & Co. KG
 Planning, building and operating

4. „Local Renewables 2018“ Freiburg i.Br., 25.10.2018
 Project Partners
 Concept of Heating Supply
 Efficient Management Strategies
 Résumé
 Study Visit
3
Agenda

5. „Local Renewables 2018“ Freiburg i.Br., 25.10.2018
Motivation
 Competition of Solar Thermal (ST), combined heat and power (CHP) and photovoltaics (PV)
 No space for central ST collector fields or large thermal energy storage in urban area
 Heat losses of district heating in range of 30 % during summer
 High PV share displaces CHP electricity in summer and leads to uneconomical operation of
CHP
 Power grid interaction of CHP is gaining importance
Pilot Scheme Freiburg-Gutleutmatten
Decentralized Solar Thermal Energy and CHP in an Urban Area
Longer phases with
self-sufficient heat
supply in summer
Grid-friendly
operation of CHP
(decentralized
storage)
Operation of
CHP
according to
electricity market
Intelligent
operation of
district heating
Solution
Decentralized
integration of
ST energy

6. „Local Renewables 2018“ Freiburg i.Br., 25.10.2018
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1. Solar Thermal energy
 Decentralized solar thermal systems on every building
 Decentralized heat storage in the buildings
2. District heating
 Connection to a existing district heating network
 Heating station with bio-methane CHP and natural
gas boilers
3. Implementation
 Connection obligation for all acquirers through the city of Freiburg
 badenovaWÄRMEPLUS builds and operates all facilities
including solar thermal energy
CO2 emissions reduced by > 80% compared to decentral supply
 Solar "full supply" during the summer months
 "Shutdown" of the district heating network in the summer
 Surplus heat is injected into the grid to supply other buildings
Realization

7. „Local Renewables 2018“ Freiburg i.Br., 25.10.2018
Building Area Freiburg-Gutleutmatten
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 Base area 8,2 ha
 Number of buildings 38 (3 ... 9 floors)
 Heated floor space 40.000 m²
 Residential units 525 (1 ... 42 per building)
 Construction standard KfW55 (55 % of legal limit)
 Heating load 5 … 120 kW
38 heat generation plants:
 Collector area 2.200 m² (8 … 179 m²)
 Buffer tanks 160 m³ (0,8 … 12 m³)
 Connected load 1.400 kW
 District heating track length 1.540 m
 Temperatures fwd/ret 75/40 °C
 Heat demand 2.200 MWh/a
 Solar yield > 600 MWh/a (> 25 %)
 Heat losses (network) 300 MWh/a (target: 200 MWh/a)
 Normal operation with "shutdown" of the district heating network expected in summer of 2

8. „Local Renewables 2018“ Freiburg i.Br., 25.10.2018
Development Plan Gutleutmatten (2014)
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9. „Local Renewables 2018“ Freiburg i.Br., 25.10.2018
Collector Systems
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Flat roofs
Green roofs (rainwater retention)
Top of collector max. 1,50 m above
building height within a distance of
1,50 m of the edge
South deviation 31 ° to SW
Specifications of the development
plan
Gutleutmatten-West
Gutleutmatten-Ost

10. „Local Renewables 2018“ Freiburg i.Br., 25.10.2018
Costs
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Investment
 Collector systems, heating stations, storage 1.900 k€
 Heating network 800 k€
 Additional costs and miscellaneous 200 k€
 Research and Development 350 k€
Total 3.250 k€
Subsidies
 EnWiSol (federal government) 330 k€
 Bafa/KfW (federal government) 440 k€
 By Customers 1.490 k€
Total 2.260 k€
The heat costs are at a comparable level with other local heating areas in Freiburg
Data net without VAT

11. „Local Renewables 2018“ Freiburg i.Br., 25.10.2018
 Project Partners
 Concept of Heating Supply
 Efficient Management Strategies
 Résumé
 Study Visit
10
Agenda

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Operation Modes
impulse

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Operation Modes
impulse

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Operation Modes
impulse

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Operation Modes
impulse

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Operation Modes
impulse

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Operation Modes
impulse

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Operation Modes
Cooperative

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Operation Modes
Cooperative

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Operation Modes
Cooperative

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Operation Modes
Cooperative

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Operation Modes
Cooperative

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Operation Modes
Cooperative

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Operation Modes
Cooperative

25. „Local Renewables 2018“ Freiburg i.Br., 25.10.2018
 Project Partners
 Concept of Heating Supply
 Efficient Management Strategies
 Résumé
 Study Visit
24
Agenda

26. „Local Renewables 2018“ Freiburg i.Br., 25.10.2018
Résumé
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 Reduction of heat distribution losses by 30 % by using decentralized ST
 Intelligent heating network control essential
 Unpopular connection obligation (especially for private customers)
 Some stressful complaining customers
 Unhappy customers who cannot realize their own ideas
 Concept suitable for professional property developers and housing
companies
 1 “standard” scheme – 38 different plants
 Hardly known and uncontrollable time schedule of the entire project
 High effort for project management, coordination, construction
management, quality assurance
 The design of mid sized solar thermal systems is not really mature
 Great potential for cost reduction and rationalization

27. „Local Renewables 2018“ Freiburg i.Br., 25.10.2018
 Project Partners
 Concept of Heating Supply
 Efficient Management Strategies
 Résumé
 Study Visit
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Agenda

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Gutleutmatten
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Gutleutmatten
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Vielen Dank für Ihre Aufmerksamkeit!
Alexander Ripka
alexander.ripka@badenova.de
Axel Oliva, Mehmet Elci, Wolfgang Kramer, Sebastian Herkel
axel.oliva@ise.fraunhofer.de

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Backup

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badenovaWÄRMEPLUS GmbH & Co. KG
 part of regional energy utility badenova AG & Co.
KG
 90 employees
 heat supply for 50.000 people
 annual sales 35 Mio €/a
 heat production 250 m. kWh/a
electricity production 80 m. kWh/a
 150 heating stations (37 kW … 43 MW)
- 40 CHP (natural gas, bio-methane)
- 14 wood-based
- 4 large heat pumps
- 2 solar thermal (30 m² CPC, 230 m² V)
 35 heat grids, network ca. 130 km

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Heating Stations in the Buildings
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34. „Local Renewables 2018“ Freiburg i.Br., 25.10.2018
 Very high individual effort, although similar “standard” systems
(communication, detailed planning, construction, site management)
 Lack of execution quality
 Standard hydraulic and control functions are faulty - not the innovative part
 The technological maturity of medium-sized ST systems is not
satisfactory!
Fraunhofer ISE, solites
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Installation and bringing into service