Workshops in Lindenberg

End of the year 2005 a new sheltered workshop was established in Lindenberg (Allgäu, Germany). The building accommodates 140 workplaces (expandable to 200) for diverse trades, 40 office work stations for the local administration and a recreation area. The building has a A/V value of 0,39. The technical building equipment comprises a wood pellet boiler to cover the peak load (capacity 140 kW), two photo-voltaic modules (capacity 24 kW) as well as three groundwater heat pumps for base load operation.

Project description

Building, overall energy concept

After an ecological-economical comparison the decision was made to build a wooden house. An evaluation of the energy demand for producing the house showed that concerning primary energy and CO₂ equivalent this solution was three times more favourable than a solid building.

Scheme of the energy concept

Photo 1: View of the community centre

Energy concept:

- Ventilation and space heating in wintertime:

The building is equipped with a forced ventilation system. A reason for that are the remarkable dimensions of rooms (up to 18 meters, e.g. workshops). The exhaust air heat exchangers have an efficiency of 70%.

Space heating coming from the heat pumps is distributed via a floor heating system. The northward located workshops got ceiling radiation heaters. Solar heated air from the workshops can be used in the offices located upstairs as preheated fresh air.

- Ventilation and cooling in summertime:

Space cooling in summertime is provided from ground water via a water-to-water heat exchanger to the floor heating system. The cooling capacity of this direct cooling system is limited to approximately 20 W/m².

Dampers and windows can be opend manually, especially exposed areas are equipped with electrically driven dampers. The glass roof got a horizontal shadow equipment.

Photo 2: View of the southern fassade with PV plant

Technical data:

- Useful floor area: 3.198 m²

- Annual heat demand: 19,4 kWh/m²a

- A/V factor: 0,39 1/m

- Average U-value: 0,37 W/(m²K).

Heat pump system

Photo 3: Heat pump room

Three groundwater heat pumps are used for space heating. The groundwater is extracted from the supply well and after usage in the heat pump fed into a creek nearby.

The peak load is covered by a wood pellet boiler with a capacity of 140 kW. It provides high temperature heat for domestic hot water preparation, ceiling radiation heaters and heater coils of the ventilation system.

Table: Technical data

Operation experiences

Originally only one heat pump had been planned. However, to be able to react on a possible falling of the ground water level finally two heat pumps were installed. Now, the plant is fail-proof and more flexible due to stepwise capacity control.

Incidents, problems:
- collapse of the groundwater well
- ground water level control problematic

Costs, economic efficiency, incentives

Investment cost:

- building construction: 999 Euro/m² net floor area

- technical installations: 452 Euro/m²

Total investment cost: 6.5 Mio Euro

Supported by the Federal Ministry of Economics and Technology (BMWi) within the incentive programme "Solaroptimiertes Bauen" (SolarBau).

Regulations, guidelines, benchmarking

No information available

References

• Database "Innovative Energie-Projekte"
  Fachinformationszentrum Karlsruhe GmbH, BINE Informationsdienst
• Objektbericht: Energieeffizienz mittels Solaroptimierung - Die Neuen Werkstätten für behinderte Menschen der Lebenshilfe Lindenberg e.V., K. Schuster et al., greenbuilding 01/08

¹ Design phase: 2002-2004
² Supply temperature: 35°C
³ direct cooling
⁴ Supply temperature: 35°C
⁵ Primary Energy Ratio: Useful heating (and cooling) energy delivered / primary energy input (kWh_UE / kWh_PE)
⁶ PEER=annual heat delivery/primery energy demand=SPF/fPE, fPE=Average European primary energy factor: 2,35 kWhPE/kWhel, Primary energy factor used in this case: 3,0 kWhPE/kWhel
⁷ Average European CO2 factor for electricity: 0,45 kg CO2/kWhel