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Application Guide /FLEXAIR-AGU-1505-E
Freecooling system is a standard feature for all Lennox rooftops,
with a two sections damper made in aluminum, and connected with
a proportional servomotor commanded by the control e-climatic
.
New buildings that comply with EPBD will have good thermal
insulation with high internal loads and will require cooling even
when outdoor temperatures are low.
Managing fresh air is mandatory in a building to control CO2
level and comfort.
Fresh air management and Free Cooling are standard features
of FLEXAIR that can reduce annual energy consumption.
SAVING ENERGY WITH FRESH AIR
& FREE COOLING
• Thermodynamic cooling can be replaced by Free Cooling
when outdoor temperature is below the building set point
saving up to 15% on annual energy consumption.
• Introducing just the required amount of Fresh Air in a building
can reduce energy consumption.
Fresh air rate in % of supply airfl ow
% Damper position
Curve А : ΔP return ducts > Fresh air: Too much fresh air
Curve B : ΔP return ducts < Fresh air: Not enough fresh air
Because a fresh air damper curve is not linear, it is not accurate
to assume that the percentage of opening of the damper is equal
to the percentage of fresh air entering the building. However, this
linear control of a damper is by far the most used in the industry
With Indoor air quality and running cost of a building being more
important to our customer, FLEXAIR can manage the percentage
of fresh air more accurately.
I
f the pressure drop in return air duct is high, the amount of fresh
air actually introduced in the building can be higher than required.
This extra fresh air will have to be cooled in summer and heated
in winter, increasing energy consumption of the system.
FLEXAIR will periodically recalibrates fresh air dampers to ensure
just the required amount of fresh air is introduced in the building.
This recalibration is achieved using the return air, outdoor air
and supply air sensors.
1.10- FRESH AIR AND FREE COOLING SYSTEM
1- GENERAL DESCRIPTION
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