Comfort cooling systems
operate by circulating room air over the evaporator coil of a vapour
compression chiller so that it becomes cooled. The system also includes a
method of rejecting the waste heat from the cooling process outside of the
building. The vapour compression cycle is used in a number of commercial room
cooling products. The main variants are: Window sill, split, multi split,
variable refrigerant flow air conditioners, water to air reverse cycle heat
pumps and chilled water fan coil units.
Window Sill Air Conditioners are the most basic form of cooling
system. They are typically used as a retrofit solution to an overheating
problem which may have arisen due to the introduction of computers into an
office space. The refrigerating equipment is contained within a cabinet which
sits on the window sill (below figure).
* Window Sill Air Conditioner
The
window must be modified to seal the remaining gap above and to the sides of the
unit. The room side of the air conditioner is sealed from the outdoor side.
Air is
drawn by a fan from the room, through a filter, over the evaporator coil and
then is returned, chilled, back to the room. At the same time outside air is
circulated over the condenser coil to carry away the waste heat. All the
controls and the compressor are fitted into the casing to create a self-contained
unit. Portable air conditioners are based on the same principle except that the
cabinet is designed to be moved into different rooms as required. A length of
flexible ducting which runs from the cabinet to the outside through an available
opening such as a window is used to discharge waste heat out of the building.
