KNX Journal 2011-1

KNX Projects
Improving the energy efficiency of an apartment
in an old building in Berlin
Energy-efficient building of historic importance
Old buildings are beautiful,
but they are rarely
well insulated. However,
improving the “interior energy
efficiency” significantly
reduces heating costs and
CO 2
emissions. Home automation
systems, such as
Synco living from Siemens
Building Technologies Division,
play an important role
in this process, as this case
study of an apartment in an
old building in Berlin shows
The Radetzky family has been
living for several years in a 180
m² apartment on the second
floor of an old building in Berlin’s
Kreuzberg district. The building
was constructed in 1906 right
next to a church. Its brick walls
and neo-gothic facade with high
lancet windows reflect the
sacral architecture of the time
to great effect. Today, it is listed
as a historic building.
Since preservation regulations
stipulate that the facade of this
historic building be kept as is, the
exterior walls lack insulation.
Despite several renovations,
the building’s thermal insulation
standard is low. For this reason,
Thomas Radetzky began to
take measures to improve the
interior energy efficiency of his
family’s apartment: In several
steps he installed the electronic
home automation system Synco
living from Siemens Building
Technologies Division. At the
same time, he carefully logged
his family’s consumption of natural
gas and electricity before
and after installing the various
system components.
Building services and
Synco living
Rooms are heated with a hotwater
radiator system (singlepipe
system; flow temperature
limited to a maximum of 75°C).
The heating curve is controlled
based on the outside temperature.
Heat is generated by
a natural gas boiler installed
in 2003. It also functions as a
Picture 1.
View of building from the south
Picture 2.
Synco living central apartment unit
with display and operating panels
Tab. 1. Physical characteristics of the building and heating systems
Characteristic
Explanation
Location
Berlin Kreuzberg
Heating degree value
20/15 (1970-2008)
3.615 Kd/a For a room temperature of
20°C, heating limit of 15°C
Year built 1906
Last renovated - Historical building
Use Residential
Usable space 180
Usage units, total 28 Multi-family building
Physical characteristics and heating:
Thermal insulation none
standard
k-value – exterior wall ~ 1,7 W/m² K Brick, 24 cm, not insulated
k-value – windows ~ 2,5 W/m² K Compound windows, wood
frames with significant leaks
Heat generator, power 16,8 kW Natural gas, wall-mounted
boiler (2003 model)
Domestic hot water
heating
central Natural gas, tankless water
heater
tankless water heater for domestic
hot water. In December
of 2006, the family installed
Synco living radiator controls
with wireless technology in
all rooms. For each room,
Radetzky programmed the
target temperatures to match
the times when the room is
actually being used. The central
unit was preset to 24°C for
Comfort mode and to 18°C
for Eco mode. If desired, these
temperature presets can
easily be overridden on an
individual basis. Settings can
be programmed quickly and
easily on the central apartment
unit (picture 2), and they can
be modified remotely from a
cellular phone.
Energy consumption
Assuming the energy consumption
for domestic hot
water heating has remained
the same, the recorded values
show a significant reduction in
electrical heat release during
the 2008/09 heating season.
For room heating, a savings
of approximately 28 % was
achieved. In the same time
period, natural gas and electricity
requirements for heating
and hot water were reduced
by 21 % and 10 % respectively
as compared to the two-year
average without Synco living.
The data shows that the
significant benefits of timeand
room-based on-demand
heating control using Synco
living are directly linked to the
insufficient thermal insulation
of the historical facade and
the major transmission and
ventilation heat losses resulting
from it. In addition, the
operation of the natural gas
boiler has been load-based
(modulating) since 2007, which
also contributed significantly
to the reduction in consumption.
Combining electricity and
gas consumption into primary
energy consumption after applying
the respective coefficient
(2.7 and 1.1) results in the situation
shown in figure 4. This
16 Journal 1/2011