Taking the heat out of humidification
February 1st 2008 Modern adiabatic humidification systems offer a number of benefits, including
reduced energy consumption compared to other systems. Lindsey Henderson of
Walter Meier (Climate UK) explains why it's time to take a fresh look
Establishing effective
humidity control in offices
and other workplaces is an
essential ingredient for maintaining a
comfortable and healthy
environment.Unfortunately,however,
there are many occasions where this
aspect of environmental control is
either overlooked or dismissed, so that
many workplaces and their occupants
suffer from low relative humidity.
Energy consumption can be used
as an excuse to trim costs from a
project.Which isn't to say that there
are no energy implications with
humidification – of course there are.
But, as with other mechanical
building services, it's important to
strike the right balance between
energy and achieving a healthy and
comfortable workplace.
To that end, there is
now considerable scope
for low-energy adiabatic
humidifiers that not only
make use of cold water,
so there is no heating
involved, but also offer
some free cooling from
the evaporation of the
water into a mist.
While adiabatic
humidifiers have been around for
many years, earlier models were
unpopular because of their potential
for spreading micro-organisms, dust
and allergens.Modern versions,
however, incorporate fail-safe
treatment mechanisms to eliminate
this risk, so that the energy benefits
can be utilised with complete peace
of mind.
In a typical office installation using
this approach, a modern adiabatic
system will be made up of a central
high-pressure system fed by partially
demineralised water, serving
atomising nozzles located at key
points in the building.The centrally
installed system also incorporates
anti-bacteria measures such as silver
ionisation, so that water conveyed to
the nozzles is safe.
The pulsation pressure from the
system will produce ultra-fine
atomising at the swirl nozzles,
with no need for compressed
air, releasing a mist that
evaporates into the air to
increase humidity and cool
the air at the same time.As
compressed air is not
required, these systems are
also very quiet.
The result is that
humidification is localised,
rather than being applied to the
entire air supply, so that the needs of
each space can be addressed very
precisely by using different types of
atomising nozzles and tailored
control strategies.
At the European headquarters of
Gallaher Group, for example, this
'direct-room' approach has been
applied to four floors of office space,
each measuring 3000m2. Each floor
is fitted with 18 wall-mounted
Draabe TurboFog nozzles to provide
a constant relative humidity of 50%,
monitored by hygrostats mounted
in each space.
Nor is this approach confined to
office space. Blaupunkt maintains
close control of humidity in its
manufacturing spaces to prevent a
build up of electrostatic charges. In
order to reduce its energy
consumption, the company has
replaced steam humidification
systems at its plants in Hildesheim,
Salzgitter and Braga with distributed
TurboFog systems.
While humidity control is the
primary objective,there are additional
benefits from adiabatic humidification.
The free cooling effect of evaporating
water into the air will generally enable
mechanical cooling systems to be
turned down,or off,during warm
weather, or all year round in spaces
with high internal heat gains.
Where there is a space heating
requirement, maintaining a relative
humidity of around 50% means that
people lose less sweat through
evaporation, compared to a drier
atmosphere, so lower temperatures
can be tolerated and the heating
can be turned down.
Adiabatic humidification systems
now offer an solution for new and
retrofit projects where energy
consumption, carbon footprint and
cost of ownership are important
considerations.At the same time,
they won't always be the best choice
for every project. So the key is to
consider the needs of each project
in its own right, calling on specific
expertise where required to arrive at
the optimum solution. More articles from Walter Meier (Climate UK) Ltd: | 
