are very demanding on their filters and air cleaning equipment
because of the presence of tobacco smoke. Filters
require cleaning or replacement (depending on the type)
because as they accumulate dirt, they block up, reducing
airflow and hence the cooling capacity of the air
conditioner. In addition some types lose filtration efficiency
as they get dirty.
There are a large number of different types of filter with
different requirements. If you have a proper maintenance
manual for the installation, refer to the manual for cleaning
advice. If you don't have a proper manual, the main types and
their normal cleaning requirements are as follows: (If you are
unsure speak to your contractor or phone Clive Blanchard,
Consulting Mechanical Engineer). In some cases more frequent
cleaning may be required.
Return air grille filters: these filters are generally
in hinged filter frames attached to the return air grille. These
filters are not really appropriate for public areas in hotels,
unless they are used in conjunction with another higher
efficiency filter or air cleaner. These filters are generally of
the washable type and should be cleaned by gently washing with
water. If they won't clean, use a mild detergent. These
filters require very frequent cleaning, at least monthly, and
often more frequently.
Deep bed filters: These are large filters usually 400 to
600 mm deep. These may be of the washable or disposable kind,
although unless your maintenance manual says otherwise, they
should normally be disposable, as the washable filters don't
remove very much tobacco smoke. The life of these varies
depending on the design and the amount of smoking they are
subject to. In general you should get at least 12 months life,
and sometimes up to three years life. It is generally better to
get your air conditioning service company to service these.
Electronic Air Cleaners: These may be stand alone units
or incorporated into the ductwork. The cores generally require
cleaning approximately once per month.
Other types of air cleaner: There are a number of other
types of cleaner. Refer to the manufacturer's literature for
details of maintenance requirements.
Getting the best
from evaporative coolers
coolers are not ideal for hotel air conditioning, except in cool
climates, or where there is a shortage of electrical power. This is
because evaporative coolers are not as effective at removing the very
high heat loads in a hotel. The exception is in hotel kitchens where
refrigerated air conditioning is simply too expensive.
However if you do have evaporative coolers, their effectiveness can
be maximised with the following ideas. Evaporative coolers rely on
three main things to be effective. These are airflow, air velocity in
the room, and effectiveness of the pads.
To ensure you get the airflow, it is necessary either to open doors
and windows, or have exhaust fans that remove nearly as much air as
the coolers supply. When opening doors and windows, avoid opening them
on the windward side if a strong wind is blowing the hot air in.
To ensure there is enough air motion in the room, it may be necessary
to experiment with the direction the grilles are blowing. Normally you
want them to blow slightly down, but spread over a wide area.
Make sure the pads are in good condition. This is particularly
important for a cooler with woodwool pads.
Commercial and industrial coolers must be maintained three monthly
when the coolers are operating. In addition if the coolers are shut
down for winter the water in the tank should be drained. For an
extensive site on evaporative coolers (albeit based on residential
cooling) go to evapcool.htm
Opening doors and
The trend to
leaving doors and windows open in dining areas to create an 'al
fresco' feel, is creating a number of problems affecting the comfort
of hotel patrons.
- Open windows mean a big increase in the heat that has to be
removed by the air conditioner. An air conditioner that is
comfortable when it is 37 degrees outside, is likely to struggle in
the low thirties if the windows are open. Thus I recommend a larger
air conditioner than you would otherwise need. Even so, don't expect
to be able to have the windows open all the time. There will still
be many hours each year when you need to close them.
- As well as requiring extra capacity, open windows increase the
temperature variation across a space, particularly if the wind is
blowing in, thus reducing comfort.
- Having opening windows can dramatically increase the energy use
of the air conditioner. This is because the higher heat load tells
the compressor to run for many more hours. This increase can be
minimised if the air conditioner is turned off in mild conditions
when the windows are open, however this requires constant attention
by your busy staff.
Hot and Cold Spots
Minimising tobacco smoke
Air velocities across serveries
Get ready for contestability
Choosing an air conditioning system
Choosing a contractor
Choosing a consultant
The advice contained in this website is of necessity of a general
nature and only addresses the most common items. It is up to the user
of the information to ascertain its suitability for their particular
case, and to seek specific professional advice if necessary.