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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

Clients:

Detlef Schmidt and Thomas Hermann

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 %