Air Conditioning & Heat Pump Services
Cool, Clean Air all Round
You Air Condition Services
Indoor air
conditioning is a key concept when constructing any modern
household. Air conditioning systems will keep you cool
during the hot summer months, and make staying in a
pleasant, relaxing experience not to be missed.
Depending on your living situation, you can purchase
various types of air conditioners. For college dorms and
smaller apartments that lack air conditioning systems, it
is very easy to go out and purchase a smaller window unit
to help with air circulation. Houses and larger commercial
building will use carefully place condensing units or even
cooling towers to power indoor air conditioning.
An air conditioner is basically a refrigerator without the
insulated box. It uses the evaporation of a
refrigerant, like Freon, to provide cooling. The mechanics of the
Freon evaporation cycle are the same in a refrigerator as in an
air conditioner.
The most common refrigeration cycle uses an electric motor
to drive a compressor. Since evaporation occurs when heat
is absorbed, and condensation occurs when heat is
released, air conditioners are designed to use a
compressor to cause pressure changes between two
compartments, and actively pump a refrigerant around. A
refrigerant is pumped into the cooled compartment (the
evaporator coil), where the low pressure and load
temperature cause the refrigerant to evaporate into a
vapour, taking heat with it. In the other compartment (the
condenser), the refrigerant vapour is compressed and
forced through another heat exchange coil, condensing into
a liquid, rejecting the heat previously absorbed from the
cooled space.
Insulation reduces the required power of the air conditioning system.
Thick walls, reflective roofing material, curtains and
trees next to building also cut down on system and energy
requirements.
Refrigeration air conditioning equipment usually reduces
the humidity of the air processed by the system.
The relatively cold (below the dewpoint) evaporator coil
condenses water vapor from the processed air, (much like
an ice cold drink will condense water on the outside of a
glass), sending the water to a drain and removing water
vapor from the cooled space and lowering the relative
humidity. Since humans perspire to provide natural cooling
by the evaporation of perspiration from the skin, drier
air (up to a point) improves the comfort provided. The
comfort air conditioner is designed to create a 40% to 60%
relative humidity in the occupied space. In food retailing
establishments large open chiller cabinets act as highly
effective air dehumidifing units.
How the Evaporation Cycle Works
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The compressor compresses
cool Freon gas,
causing it to become
hot, high-pressure Freon gas.
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This hot gas runs through a set of coils so it can
dissipate its heat, and it condenses into a
liquid.
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The Freon liquid runs through an expansion valve, and
in the process it evaporates to become
cold,
low-pressure Freon gas.
This cold gas runs through a set of coils that allow
the gas to absorb heat and cool down the air inside
the building.
Mixed in with the Freon is a small amount of lightweight
oil. This oil lubricates the compressor.
Window Air Conditioners
A window unit implements a complete air conditioner in a
small space. The units are made small enough to fit into a
standard window frame. You close the window down on the
unit, plug the unit in and turn it on to get cool air. If
you take the cover off of an unplugged window unit, you
will find that it contains:
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A
compressor
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An
expansion valve
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A
hot coil (on the outside)
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A
chilled coil (on the inside)
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Two fans
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A
control unit
The fans blow air over the coils to improve their ability to
dissipate heat (to the outside air) and cold (to the room
being cooled).
Maintenance
Neglecting necessary maintenance
ensures a steady decline in air conditioning performance
while energy use steadily increases.
Keeping your system
properly maintained will lower energy and repair costs,
prevent breakdowns and prolong the life of your equipment.
Some maintenance jobs should be left to the
professionals, but there is much that you, as a
homeowner, can do to prolong the life of your equipment,
keeping it running at peak efficiency.
Air Conditioner Filters
The most important
maintenance task that will ensure the efficiency of your
air conditioner is to routinely replace or clean its
filters. Clogged, dirty filters block normal airflow
and reduce a system's efficiency significantly. With
normal airflow obstructed, air that bypasses the filter
may carry dirt directly into the evaporator coil and
impair the coil's heat-absorbing capacity. Filters are
located somewhere along the return duct's length. Common
filter locations are in walls, ceilings, furnaces, or in
the air conditioner itself.
Some types of
filters are reusable; others must be replaced. They are
available in a variety of types and efficiencies. Clean or
replace your air conditioning system's filter or filters
every month or two during the cooling season.
Filters may need more frequent attention if the air
conditioner is in constant use, is subjected to dusty
conditions, or you have fur-bearing pets in the house. If
you use a disposable type filter, it's always wise to keep
several spares inside the house.
Sealing and Insulating Air Ducts
An enormous waste of
energy occurs when cooled air escapes from supply ducts or
when hot attic air leaks into return ducts.
Recent studies
indicate that 10% to 30% of the conditioned air in an
average central air conditioning system escapes from the
ducts.
For central air
conditioning to be efficient, ducts must be airtight.
Hiring a competent
professional service technician to detect and correct duct
leaks is a good investment, since leaky ducts may be
difficult to find without experience and test equipment.
Ducts must be sealed with duct "mastic." The old standby
of duct tape is ineffective for sealing ducts.
Obstructions can
impair the efficiency of a duct system almost as much as
leaks. You should be careful not to obstruct the flow of
air from supply or return registers with furniture,
drapes, or tightly fitted interior doors. Dirty filters
and clogged evaporator coils can also be major
obstructions to air flow.
The large
temperature difference between attics and ducts makes heat
conduction through ducts almost as big a problem as air
leakage and obstructions. Ducts in attics should be
insulated heavily in addition to being made airtight.
Outside Units
Dirt, leaves, grass and other debris clog the condenser
coils, straining the system.
Once a month,
inspect the outdoor unit to insure that nothing is
obstructing the airflow across the coil. Remember, before
you do any work on your condenser unit
turn off the power
at the disconnect switch mounted on the wall near the
unit. If you don't have a disconnect switch, turn off the
breaker. If you find that your unit is becoming dirty, you
can follow the procedures below.
Performing Outside
Maintenance
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After disconnecting the power, if leaves or other
debris have collected inside the condensing unit, open
the unit by undoing the screws on the top panel and
tipping it up. Remove any debris from the enclosure.
Then, reverse the procedure insuring the screws are
replaced before restoring power.
Do not open
the electrical panel cover. This is best left to a
certified technician.
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Check to be sure your compressor
unit is level. An unleveled unit will be
nosier, less efficient, and cause excessive wear.
Check the level in both directions, making adjustments
if necessary.
Be careful how much you move the unit.
It has rigid connections to the electrical and
refrigerant lines. Too much (and it doesn't take much)
movement could cause a refrigerant leak to occur.
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Finally, check
the condensate line for a bacterial slime that
tends to grow in condensed water. The condensate line
is the drain that removes water that has condensed
from your indoor coil. Pour a 1:9 bleach-and-water
solution through the line. Find the fitting for the
hose, pull it out, and flush the line all the way to
the floor drain.
If the drain
is difficult to reach, you may be wiser to call your
HVAC (Heat, Ventilation and Air Conditioning)
contractor to do the job.
Always be careful when
using lawn mowers and trimmers around your condensing
unit. Flying debris can damage the coil and fins.
A Word about Heat Pumps
Imagine that you took an air conditioner and flipped it
around so that the hot coils were on the inside and the
cold coils were on the outside. Then you would have a
heater. It turns out that this heater works extremely
well. Rather than burning a fuel, what it is doing is "moving
heat."
A heat pump is an air conditioner that contains a
valve that
lets it switch between "air conditioner" and "heater."
When the valve is switched one way, the heat pump acts
like an air conditioner, and when it is switched the other
way it reverses the flow of Freon and acts like a heater.
Heat pumps can be extremely efficient in their use of
energy. But one problem with most heat pumps is that the
coils in the outside air collect ice.
The heat pump has to melt this ice periodically, so it
switches itself back to air conditioner mode to heat up
the coils. To avoid pumping cold air into the house in air
conditioner mode, the heat pump also lights up burners or
electric strip heaters to heat the cold air that the air
conditioner is pumping out. Once the ice is melted, the
heat pump switches back to heating mode and turns off the
burners.
Maintenance is similar to straight air conditioners and
usually serviced by the same contractors.
Heat, Ventilation
and Air Conditioning (HVAC) Contractor. Your contractor may be required to have a license, depending on
your province/state or local requirements. They should be
well trained, and experienced to provide quality
installation and repair. Don't be afraid to ask you
contractor about his or her training, experience, and
membership in associations.
Contractors are required to be certified to handle refrigerant in
cooling systems. They are also required to own and use
refrigerant recovery equipment. Ask for proof that your
contractor is certified. Check the contractor's record and
their performance. Get a list of their past projects and
take a look at their work. Call the Better Business Bureau
to find out if there have been any complaints against them
and get a list of references from the contractor.
This paper is
intended for informational purposes only.
Nothing contained herein constitutes legal, financial or
other professional advice. Transmission of these materials
is not intended to create, and receipt does not
constitute, any relationship of any kind between the
provider and the recipient. Some of these points may not
apply in your area. Different term and conditions may vary
from state to state and province to province. All
articles, text and photographic material presented here is
for the use and pleasure of the recipient only.
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