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
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
6
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
9. „Local Renewables 2018“ Freiburg i.Br., 25.10.2018
Collector Systems
8
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
9
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
26. „Local Renewables 2018“ Freiburg i.Br., 25.10.2018
Résumé
25
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
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
33
Installation and bringing into service