Client:
AS Solar
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Nenndorfer Chaussee, Hannover
Description
In June of 2011, AS Solar moved into its new head offices in Hannover: a modernized, highlyefficient industrial construction which, by consistently using solar energy and biomass technology, produces more energy than it consumes.
Built in 1959, the former Telefunken building had been sitting empty for more than 10 years, and had been severely damaged by vandalism. It is a rectangular structure (94 m x 53.5 m) with a height of 12.1 meters. The basement under the western part of the building extends up to 6.2 meters underground; above ground, it has a three-story front structure plus a main structure with two halls situated one above the other. After completely gutting the reinforced concrete frame, the construction team created around 6,000 m2 of office space in addition to the production and logistics areas. Different efficiency standards were used in each area, depending on the interior temperatures desired: offices and similar spaces were constructed to meet Passivhaus standards; the circa 1,000-m2 manufacturing area was renovated in accordance with the German Energy Savings Regulations of 2009; and the approximately 2,400 m2 of gross storage area space remained unheated.
Parties involved
Design:
Architect John M. Frank
Energy concept:
Prof. Dr. Ing. Lars Kühl, energydesign braunschweig GmbH
Building data
Building type:
Office, production and storage building
Location:
Hannover-Bornum
Year of construction:
1959
Modernization:
2008-2011
Units:
Building with ca. 200 workspaces
Heated usable space:
6.062 m²
Subsidies:
proKlima
Initial condition
Exterior Walls:
8 meter-wide, prefinished panel elements with 24 cm cellulose insulation; insulation of space between new and existing structures with mineral wool or perlite filling material; strong 6 cm-thick softboard wood-fiber panels on exterior side to hold plaster; HTC = 0.12 W/(m2K)
Windows:
curtain wall with heat-insulating triple glazing; HTC = 0.8 W/(m2K)
Roof:
Existing flat roof covered with 45 cm cellulose filling material and plastic foil, then overlaid with new wooden construction plus trapezoidal sheeting, designed as ridge roof; PV modules affixed on top; HTC = 0.11 W/(m2K)
Basement ceiling:
10 cm wood fiber insulation installed under existing ceiling; HTC = 0.21 W/(m2K)
Daylight-usage:
Four skylights were cut into the construction to help illuminate the office area on the top floor. Light-directing elements optimize usage of daylight. Artificial lighting is controlled with presence detectors based on daylight levels.
Modernization in detail
Ventilation:
Ventilation system with heat recovery; max. flow volume of 15,300 m3/h for seminar rooms, bistro, foyer, kitchen, and adjacent rooms; separate roof ventilator for kitchen outlet air
Heating:
Heat generation via wooden pellet-boiler cascade and vacuumtube collectors
Air conditioning:
Reduced solar gains in summer by using sun-protective glazing and a movable exterior sun shade; offices cooled in summer using a solar heat-powered absorption refrigerator with 2 x19 kW of cooling power; 160-kW compression refrigerator for peak temperature loads
Photovoltaics:
286 kWp on the roof of the head office; 126 kWp on the main parking lot
Rainwater-usage:
30 m3 cistern
Measured values
AIRTIGHTNESS:
n50= 0.6 h-1
Calculated values
Calculation method: Passivhaus planning package; Initial values: Hannover building typology
HEATING ENERGY NEEDS:
15 kWh/(m²a)
TOTAL ENERGY NEEDS FOR HEATING,AIR CONDITIONING,DHW,ELECTRICITY:
Pellets
24 kWh/(m²a)
Electricity
26 kWh/(m²a)
Total energy generated:
PV SYSTEM
Electricity
ca. 250.000 kWh/a
PRIMARY ENERGY NEEDS FOR HEATING,AIR CONDITIONING,DHW,ELECTRICITY:
71 kWh/(m²a)
including credit for generated electricity: Plus Energy standards met
CO2-EMISSIONS FOR HEATING,AIR CONDITIONING,DHW,ELECTRICITY:
17 kg/(m²a)
including credit for generated electricity: Plus Energy standards met
