Where renewable and recoverable energy combine
Our innovative Econet system is
saving energy in several ways
T he components in Fläkt Woods’ inno-
vative Econet system are connected to-
gether to provide a more reliable and more
This is highly beneficial from an environmen-
tal point of view because much less energy
is used to transport the air through unneces-
efficient AHU system. Heat recovery, heating sary components. Further development of the
and cooling are integrated into a common cir- principle of energy recovery has also led to
cuit as heating/cooling coils, pumps, valves, increases in efficiency of 50% compared with
pipe systems, insulation, etc. The result is a traditional coil recovery systems.
shorter and more compact ventilation unit.
Dry-box solution (accessory) Twin pump solution (accessory)
High moisture combined with impurities in the A twin pump solution is available for Econet. This
outdoor air can sometimes damage the outdoor is the optimal solution for buildings where the
air filter. To protect the outdoor air filter, the pre- ventilation is crucial for an ongoing process and
heater coil has traditionally been installed before Econet must never stop. If one of the pumps has
the filter. This traditional solution reduces the a breakdown, the twin pump solution sets the
energy recovery by 30%. Therefore, with Econet other pump going.
dry-box solution both coils are connected in the
supply air instead. Advantages of this system
are that there is no impairment of the recovery, Heat exchanger package
the system is self-regulating and the compo- (accessory)
nents are protected from failure with the help of In most cases some form of supplementary
Econet’s frost protection. heating or cooling is necessary. Instead of or-
dering cooling/heat exchanger separately, Fläkt
Controls Woods offer a complete heating exchanger
The control unit for Econet’s recovery function package. This means that shorter delivery times
has been updated and has been given more flex- are possible, and better precision is achieved in
ibility and better functionality. The control unit the building.
can also be supplemented with its own efficien-
cy/energy measurement function.
Problem: Energy consumtions in buildings
We spend approximately 90% of our time heating and cooling through the ventilation
indoors. A lot of energy resources are con- system we have a lot to work with. Together
sumed to maintain the right temperature that means that you can make an impact on
and air quality, which is becoming more and somewhere about half of the total energy
more important. On average, 68% of a build- consumption of a building when focusing on
ings energy needs are spent on heating, cool- ventilation. That is something worth consid-
ing and ventilation. Since we can affect both ering!
Solution: Energy efficient systems
An obvious energy approach is to reuse the were previously unusable can be used in the
heat and cooling. This mostly applies to reuse Econet system.
of excisting energy in the exhaust air. It is best An example of system optimization is to com-
achieved by using a recovery system with the bine Econet with a chiller. The temperature of
highest recovery rate. Econet has a recovery the cooling water is usually determined with
rate of 65 -75%. reference to the requirement of the ventila-
tion unit, which leads to a relatively low cooling
System optimization water temperature (6ºC). This means that the
Through its intelligent design, Econet is able to efficiency of the chiller is limited. If an Econet
influence the entire energy chain. Thanks to the system is used instead, the cooling water tem-
high degree of efficiency, the energy require- perature can be increased significantly. This
ment can be reduced steeply. The entire energy leads to a more efficient and smaller chiller,
chain from production, distribution to consump- smaller pipe dimensions and pumps, i.e. econo-
tion can be optimized with the help of Econet, mies in both investment costs and operating
thanks to the fact that energy sources that costs are possible.
LCC sums it all up
Within the industry we use an analysis ap-
proach called “Life Cycle Cost“ when design-
ing ventilation systems. It balances the cost of
better components and smarter system con-
trol with savings in maintenance and energy
costs over the system’s life time.
Not surprisingly, a more expensive system
with better quality will be the cheapest solu-
tion in the long run as savings are made in
energy and maintenance.
The design temperature in a heating system is traditionally Econet can cool a building with other water temperatures
80/60°C. Econet is a low-temperature system, which means that traditional systems. About 10ºC cooling water is in
that it is possible to use heating water at a temperature of most cases sufficient as a feed temperature, whereas the
25-35ºC. This means that there is a possibility of utilizing hot return temperature of the cooling water can be as high as
water that was previously considered to be unusable. The 22-26ºC. If a chiller is used, the cooling factor (COP) is in-
heat source for Econet can be the return water from district creased as a consequence of a better working point. Econet
heating, waste/condenser heat or return water from radiator is always prepared for cooling, which makes it possible to
systems, for example. add cooling in a later stage.
Econet makes everybody a winner
To lower the costs and care for the environment, Econet makes it possi-
ble to use alternate energy sources instead of traditional. Thanks to this,
Econet makes everybody a winner.
Heat energy from a chiller Heat pump
Refrigerators give off heat (condenser heat) The lower the hot water temperature pro-
when they produce cold. Liquid-borne con- duced by a heat pump, the better the operat-
denser heat from chillers is very often at a ing economy. Econet can significantly lower
low temperature (30-36ºC), which in the past the hot water temperature down to a level
has meant that it cannot be used and thus of approximately 30ºC. This means that we
goes to waste. Econet can utilize the waste have a more efficient and smaller heat pump
heat in order to heat the supply air. This way with better operating economy.
of saving energy is efficient in food shops
Energy from district heating +23 °C
Econet can utilize lower hot water tempera-
tures, which makes it entirely possible to 18 °C
utilize the return heating water from the 27 °C >30 ° C
radiator system, for example. This means
that the return heating water to the district
heating network can be lowered to 20-25ºC -5 °C +20 °C
in optimal cases, which results in reduced
Energy from district cooling Energy from ground source cooling/
In a district cooling system, it is important seawater
that the temperature of the return water The temperature in the ground is largely
to the district cooling system is as high as constant (8-10ºC), i.e. it is more or less
possible. In an Econet system, the highly unaffected by the season. The temperature
efficient coils can return the desired tem- can rise slightly during the late autumn,
perature level to the cooling water without however, and this can lead to problems in
over dimensioning the cooling coil in the making use of the ground source cool-
ventilation unit as in traditional systems. ing. Econet can utilize temperatures of up
to 12ºC, which means that the system is
excellent for these environmentally friendly
29°C 19°C 24°C The exhaust air unit can be supplemented
with a humidifier section where cooling
recovery is desired, and indirect evapora-
< 10 °C tive cooling can be utilized in this way. This
method can significantly reduce the cooling
effect requirement from the chiller, which
32°C 16°C results in a smaller chiller and lower operat-
Over 1000 Econet systems installed
Econet in superstores Econet in industries
The regrigerated counters emit waste heat Within industry there is usually waste heat
that Econet can reuse. This energy is often available. This heat is frequently sufficient for
wasted, but Econet uses it to heat the supply Econet to heat the air, i.e. no primary heating
air. is required to heat the air. Due to the recovery
principle employed by Econet it is possible to
References: ICA Maxi, Jönköping, Haninge, position the units separately from each other,
Sweden/Prisma, Turku, Finland in addition there is no transfer of contaminated
Reference: Volvo, Gothenburg, Sweden
Econet in offices and commercial Econet in hospitals
Buildings In hospitals it is of severe importance that
The ventilation requirements in these types of there is no leakage flow between supply- and
buildings vary during a day. Econet combined exhaust air in order to keep the indoor air
with a VAV system creates a demand control- hygienic. For the same reason, the ventilation
led ventilation, which gives a high comfort but units also have to be easy to maintain. That is
saves energy when the rooms are empty. Coil why only indirect energy recovery can be used,
recovery in Econet garantees no leakage flow i.e coils. As the ventilation is in use day and
between supply and exhaust air and decreases night reuse of energy is important in order to
the length of the unit. These buildings often decrease the energy costs. Econet is the best
have access to ground source heating/cooling, option for that.
and that makes Econet a perfect solution.
References: Akademiska Hus, Lund, Uppsala, References: TYKS, Turku, Finland/St. Olav
Gothenburg, Sweden/Frankfurt Airport, Frank- Hospital, Trondheim, Norway/Imperial College,
furt, Germany/NATO, Brussels, Belgium/Bris- London, UK/Jansson Pharmacia, Antwerpen,
tol Museum, Bristol, UK Belgium
Increasing energy prices, legislation and a more environ-
mental consideration raise the demands and old tech-
niques are challenged with innovative solutions.
Our Econet system contains of an air handling unit and a prefabricated pump group that con-
trols the system. A heating exchanger package can be delivered as an accessory.
The winning ideas of Econet
- One common circuit for heating supply, - Perfect for renewable energy sources
cooling and heat recovery results in a di- such as ground source water for cooling
minished need of circulation pumps, pipe and waste energy for heating.
systems, valves, insulation etc. The result
is a shorter unit and in most cases less - The possibility of utilizing cooling recov-
pressure loss. ery reduces the cooling effect requirement
and evaporating cooling agent
- A flexible control system that optimizes
the reuse of energy. - Freeze-proof system
- High recovery rate, especially suited for - Separate air flows provide no air trans-
variable air velocity systems. fer.
- Exceptionally low temperature require- - Our Dry-box solution protects the supply
ment for hot water, allows the utilisation of air filter without having a negative impact
alternative sources of thermal energy. on the recovery.
- Ideal for district cooling/heating.