SEIFERT Variable Speed Air Conditioner KG 2025-24V - Manual (Page 11)

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3. Technical Information
3.1 Concise unit description
The air conditioner is used where heat needs to be dissipated from outdoor cabinets in order to protect
heat sensitive components. The unit has two completely separate air circuits which ensure that the
clean cabinet air does not come into contact with the ambient air which may well be dirty or polluted.
Outdoor cabinet air conditioners can dissipate large quantities of heat from outdoor cabinets into the
ambient air and at the same time reduce the cabinet internal temperature to below that of the ambient
air.
3.2 Functional principles
The unit functions on the principle of the compression refrigerator. The main components are:
refrigerant compressor, condenser, expansion valve and evaporator. These four components of the
refrigerant plant are connected with each other by pipes to form a hermetically sealed system in which
the refrigerant (R134a) circulates. R134a (C
2
H
2
F
2
) is chlorine-free and has an ozone destruction
potential (ODP) of 0.
3.3 Description of operation
When the unit is in operation the compressor draws in refrigerant vapor from the evaporator. The
necessary energy needed to vaporize the refrigerant is taken from the cabinet air which flows through
the evaporator. This cools the cabinet air which is then blown back into the cabinet by a fan. The
refrigerant vapor, which has been drawn in by the compressor, is pumped under high pressure into the
condenser. There the heat which has been taken from the evaporator and compressor is dissipated in
the ambient air which flows through the condenser. This condenses the refrigerant and the resulting
heat is again passed on to the atmosphere .The expansion valve reduces the refrigerant to the
necessary evaporator pressure. The introduction of heat evaporates the refrigerant. The evaporator is
designed to fully evaporate the refrigerant. The refrigerant circuit is then complete.
3.4 Unit controls
The unit is controlled in relation to the cabinet internal air temperature. A sensor constantly measures
the air temperature as it is drawn into the unit from the cabinet. The compressor speed is varied
according to the reading taken by the sensor in such a way to operate in the most efficient manner and
to limit the switching on and off of the compressor. This helps to keep the temperature inside the
control cabinet as constant as possible in order to reduce temperature induced stress on the
components and fluctuating temperatures. The speeds of the ambient and internal fans are regulated
for optimal performance of the unit.
The ambient air fan (condenser) switches on and off together with the compressor in order to save
energy. The cabinet air fan runs continuously, independent of the compressor, to provide constant air
circulation and maintain an even temperature in the cabinet.