Clients:
Detlef Schmidt and Thomas Hermann
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Oesterleystrasse, Hanover
Description
The insights are similiar: who wants to modernize the one watchs one the same also for other deficiencies. Especially, if thermography takings reveal the buildings heat loss relentlessly. After a first consulting through an energy adviser and incorporating the house as a dena-model house, the buildings modernization project began. The aim was, to reduce energy needs to 50 percent of a comparable new build. For that reason, besides other subsidies, a repayment grant from the KfW development bank in the amount of 20 percent of the loan volume was offered. The dedicated project had need of big steps: heating and water heating is realized since 2008 through a gas fired cogeneration heat and power plant, which generates besides heat as well electricity. 3 of 6 flats consume the generated electricity on their own, everything else is fed into grid. Valuable insulated were roof, exterior walls and basement ceiling, but even the buildings base received an insulation. Heat insulation and solar energy generation are the main characteristic of the new installed valuable passive house windows. A central controlled comfort ventilation system with heat recovery functions distributes constantly fresh and well-temperated air. With a competent guide, the leaseholders grew to like nearly each of the passive houses strengths and now enjoy the new awareness of life.a
Involved parties
Design:
clients, Ing.-community Bau+Energie+Umwelt, energy adviser Thomas Titz
Building data
Building type:
Apartment house
Location:
Hanover
Year of construction:
1952
Modernization:
20008 - 2009
Residential units:
6
Heated usable space:
480 m2
Subsidies:
KfW, dena, BAFA, proKlima
Initial condition
EXTERIOR WALLS:
massive lime-sand brickwork, HTC ? 1,0 W/(m2K)
WINDOWS:
mix of wooden and plastic windows with isolating glazing, HTC ? 2 – 2,5 W/(m2K)
ROOF:
uninsulated rafters roof
BASEMENT CEILING:
uninsulated in-situ concrete ceiling
VENTILATION:
Window ventilation, as well as typical old building joints and cracks
HEATING:
about 30 years old gas heating, hot water via electric water heater
Modernization in detail
EXTERIOR WALLS:
18 cm heat insulation system made of polystrene, quality 0,032 W/(mK), HTC = 0,16 W/(m2K)
WINDOWS:
new passive house windows with heat insulating 3-panze-glazing in synthetic profile, HTC = 0,8 W/(m2K)
ROOF:
doubling the existing roof rafters to overall 30 cm, laying a vapor barrier and 30 cm mineral wool insulation, quality of 0,035 W/(mK), HTC = 0,16 W/(m2K)
BASEMENT CEILING:
insulation of the basement ceiling with 10 cm polystrene from underneath, quality 0,032 W/(mK)
VENTILATION:
comfort ventilation system with heat recovery functions for each apartment
HEATING:
new gas-fired cogeneration plant with a heat output of 4 to 12.5 kW (modulating) and 1.3 to 4.7 kW of electrical power, centralized hot water in kitchens and bathrooms
AIR CONDITIONING:
no active air conditioning installed
Measured values
AIRTIGHTNESS:
n50 = 1,2 h-1
Calculated values
Calculation method: Passivhaus planning package; Initial values: Hannover building typology
HEATING ENERGY NEEDS:
BEFORE
160 kWh/(m²a)
AFTER
39 kWh/(m²a)
SAVINGS
76 %
TOTAL ENERGY NEEDS FOR HEATING,AIR CONDITIONING,DHW,ELECTRICITY:
BEFORE
Gas
224 kWh/(m²a)
Electricity
35 kWh/(m²a)
AFTER
Gas
101 kWh/(m²a)
Electricity
17 kWh/(m²a)
TOTAL GENERATED ENERGY (AFTER):
CHP station
Electricity
13.600 kWh/(m²a)
PRIMARY ENERGY NEEDS FOR HEATING,AIR CONDITIONING,DHW,ELECTRICITY:
BEFORE
342 kWh/(m²a)
AFTER
84 kWh/(m²a)
SAVINGS
75 %
CO2-EMISSIONS FOR HEATING,AIR CONDITIONING,DHW,ELECTRICITY:
BEFORE
77 kg/(m²a)
AFTER
17 kg/(m²a)
SAVINGS
78 %
