MAKING MODERN LIVING POSSIBLE
Danfoss Heat Transfer Station
for the energy self-contained community of Kněžice
One hundred and fifty
households in the energy
self-contained community
of Kněžice in the area of the
town of Nymburk use the
Danfoss VX heat transfer
station for connection to the
system of central heating
and delivery of hot water.
The Danfoss Company takes a
share in a unique project for the
energy self-contained community
of Kněžice. In this community with
five hundred inhabitants, situated
close to the town of Nymburk in
the central part of Bohemia, an
ecologically balanced system of
heat and electric energy production based on a renewable energy
source came into existence during
the last two years.
At the beginning of that energy
chain there are biological products
burnt at a boiler plant; it concerns
biomass and wastes from agricultural production, households and a
near water purification plant, from
which biogas is produced that drive a cogeneration unit. At the end
there are one hundred and fifty
households centrally supplied with
heat and hot water, ecologically
processed wastes and more than
two thousand megawatt-hours
annually supplied to the electrical
power system. Heat and hot service water are supplied by the biomass boiler house; electric energy
is produced by the cogeneration
unit driven by biogas. The community is energy self-contained and
disposes in an exemplary manner
of wastes and energy sources that
are available for it.
Return to energy independence
“A primary impulse of our project
was our effort to return to rustic
roots of the local region and become again more independent on
environs,” Milan Kazda, the energic
mayor of the Kněžice community
and a father of the whole idea,
says. And he adds: “Of course,
endeavor to reduce local heating
and improve economy of our community played a big part as well.
In addition, the whole production
complex has created several new
workplaces and total renovation of
the village was initiated.”
Community’s energy system
covering the biomass boiler house,
biogas station, a line for pellet
production, and electric and heat
distribution was financed by
EU funds at the amount of 75%.
10% was sponsored by the State
Environment Fund, and the rest
was financed by the community. The total costs climbed up to
CZK 135 million. As the general
contractor the building company
Skanska served.
According to mayor Milan Kazda,
building of the whole system has
brought also important secondary
effects that improve living conditions in the community. “During
the last years we built a modern
nursing home, for which costs for
heat and hot water have been
reduced in a markedly way thanks
to our energy system. Also people
working with the energy plant and
equipment can otherwise help in
our community”, Mr. Kazda says.
Danfoss ensured the household
heating system
The Danfoss Company played
a key role as for connection of
households to the heating and
hot water distribution system.
In every family house, of which
overwhelm majority of connected
households composes, a Danfoss
VX heat transfer station has been
installed now, i.e. an integrated
independent control system that
controls an installed two-way
valve equipped with an electric
motor drive serving for right flow
adjustment towards a plate heat
exchanger. The station is equipped
with the user friendly electronic
control unit – Danfoss ECL 100 M.
Also an AVPB/F differential pressure regulator has been used, which
guarantees hydraulic stability of
the whole heating network.
This highly effective regulator
makes adjustment of right differential pressure possible at every
station in such a way that delivery
of correct heat amount can be
ensured without any redundant
Kněžice won European Energy Award
for energetic efficiency
The municipality of Kněžice won European Energy Award for
the construction of unique biogas station with cogeneration
unit and for other saving measures in the municipality. The EEA
program awards cities and municipalities in the European Union
which decrease energy intensity and use renewable resources
of energy. Its partner in the Czech Republic is nonprofit organization “Seven” that focuses on environmental protection and
support of economic development by means of more efficient
use of energy.
In Kněžice, the independent auditor appreciated especially
energetic self sufficiency of the municipality and introduction of
central heat distribution system, which lead to significant decrease in CO2 emissions. The awarded project includes central gas
supply system with heat distribution, in which central biomass
boiler and biogas station, which produces electricity and heat all
year round, serve as sources. Most of the houses in the municipality use ecological heating by renewable resources.
The electric output of the biogas station is 330 kW and the heat
output is 405 kW. Its annual production amounts to approximately 2600 MWh of electricity and in addition to electricity, it
produces high-quality fertilizer. The output of biomass boiler is
1.2 MW.
surplus flow rate. This surplus flow
rate causes non-economic operation of stations, noisiness and
mainly pressure instability and
bad heating of end heating branches. At every station a Grundfos
Alpha+ circulating pump has been
installed, which ensures effective
and silent operation of the heating
system also with the use of radiator thermostats.
Distribution at the stations has
been made of stainless tubes and
thus the long service life can be
ensured. Hot water inlet has been
connected to the present systems
– mainly storage tanks – and so hot
water preparation is carried out in
such a way like users were accustomed to. For hot water heating
a separate pump has been used
that pumps heating water into the
heating elements of the present
boiler tanks. Heat amount coming
to the station is measured by heat
meters with remote reading devices. In every meter an M-BUS card
has been installed that can transfer
required data to the central control
room.
During installation of the Danfoss
VX stations neither revision nor
chimney as well as gas installations
inspection was necessary. Solid
fuels ensuring, their handling and
storage are not necessary now.
Customer’s opinions
Interview with Mr. Milan Kazda,
mayor of the Kněžice community
What is your experience as for the
annual function of the community’s
energy self-contained system?
We passed a hard period, in which
function of the complex system
had to be tuned, i.e. the system that
has never been built anywhere by
anybody. With my colleagues we
spent more than one night at the
boiler house and the cogeneration
unit, however, now everything is in
operation according to the project.
The central heating system functions
perfectly; furthermore, we prepare
roofing of the biogas station storage
bin in order that people cannot be
troubled with odours escaped from
it.
How did you persuade inhabitants
to agree with the central supply of
heat energy and hot water?
From the beginning we discussed
frankly about costs of the whole
action and we have held the price of
heat we supply to inhabitants. The
people gradually found out that it is
advantageous and that the central
heating is cheaper than the local gas
or electric heating. As for the price,
we surpassed coal as well. In the
Kněžice surrounding there is lack of
wood and in addition to it, wood is
storage space intensive. Thus situation is finally relatively unambiguous.
Central heating and hot water supply
from the renewable sources are the
cheapest.
And what about your experience as
for the Danfoss stations?
At the town hall we have one connecting station and up to now we
have not noted any difficulties. Regulation works well, households do not
complain. Service is well ensured,
and so we are totally satisfied with
the supplied system as well as the
equipment type. Many households
appreciate the possibility of simple
connection of the present systems
and quality electronic regulation.
Basic project data
Pressure-independent Danfoss
VX station
Electronic regulator DANFOSS
ECL 100M
Danfoss VX is an independent
heating station. The station ensures heating and it is equipped
with a connection pipeline for the
primary side with a flexible spacer
at the return part of the primary
circuit for additional assembly of
a heat meter. The station is also
fitted with a plate heat exchanger,
regulating valve and the ECL 100
M control electronic device. An
expansion tank and the Alpha+
pump ensure safe, effective and
noiseless operation of the heating
system also with the use of the
radiator thermostats.
It is a very effective and user
friendly regulator that controls an
installed two-way valve with an
electric motor drive serving for
right flow adjustment towards the
Danfoss plate heat exchanger. The
regulator ensures quality operation and it is necessary to be professionally connected. Individual
adaptation to the present technical solution influences operation
effectiveness.
AVPB-F differential pressure
regulator with flow rate limitation
The use of this regulator ensures
hydraulic stability of the heating
system in the village and makes
right adjustment of differential
pressure possible at every station
in such a way that delivery of correct heat amount can be ensured
without any redundant surplus
flow rate. AVPB-F regulator makes
also static adjustment of hydraulic
parameters in the network possible. Thus it is a “fix point” of the
hydraulics system and it markedly
participates in quality of the system hydraulic stability.
Danfoss solution advantages
• Preservation of the heating
system hydraulic stability of the
whole community
• Preparation for various local
systems in households
• Correct heat delivery without
any redundant surplus flow rate
• Economic operation, noiseless
and pressure stability
Danfoss s.r.o., V Parku 2316/12, 148 00 Praha 4 - Chodov, Česká republika
Telefon: +420 283 014 111, Telefax: +420 283 014 567, Homepage: www.danfoss.cz, E-mail: [email protected]