3
Design and function
3.1 Unit description
In cooling mode, the unit (an air-cooled chiller)
takes heat out of the operating medium to be
cooled, water or a mixture of water and glycol,
within a closed medium cycle in the evaporator
(plate heat exchanger) and passes it on to the
closed cooling cycle.
As a consequence of the heat exchange, the
medium cools and the refrigerant in the cooling
cycle vaporises under low pressure. The gaseous
refrigerant enters an electric compressor (scroll
construction) which increases the pressure and the
temperature of the refrigerant.
The gaseous refrigerant is led into a finned con-
denser, which, as a consequence of the heat
exchange, condenses the refrigerant under high
pressure to a liquid.
The air emerging at the condenser heats the envi-
ronment. The liquid refrigerant is fed by means of a
variable injector valve back to the evaporator
where the circuit begins again. In heating mode, a
chiller with heat pump functions (HP-function) can
take up heat from the ambient air in the finned con-
denser and pass it on to the operating medium. A
reversing valve switches the cooling cycle function.
A return temperature dependent, adaptive con-
troller, which ensures the unit's operation and all of
the safety functions, is used to control the cooling
or heating capacity. A potential-free contact pro-
vides for remote enabling.
The unit is designed for outdoor installation. Under
certain circumstances, it can also be used in
indoor areas.
The unit cooling cycle comprises an evaporator,
compressor, thermal injection valve, condenser,
condenser fan, fan control system and high and
low pressure switches. Units with heat pump func-
tion also have a reversing valve and a collecting
flask.
The medium cycle comprises a circulation pump,
expansion vessel, safety valve and differential
pressure switch.
A storage tank is not mandatory.
Winter pressure controls, cabled remote control,
crankcase heating, vibration dampers, heaters for
anti-freeze protection, external medium storage
tanks, glycol concentrate and a technical assis-
tance commissioning are available as accessories.
3.2 System layout
The unit is designed for a 2-conductor system.
The system has 2 medium pipes (conductors:
Supply and return flow) for cooling using a cold
medium. In combination with a corresponding
system, the output can be transmitted to the room
to be cooled via the floor, the building structure or
by means of ceiling cooling. For each of the dif-
ferent systems, a minimum flow volume and a min-
imum medium volume must be ensured for the
plant.
B
1
A
4
1a
3
1
2
1
1
1c
1b
3
3
B
3
B
2
5
6
3a
Fig. 3: System layout
A:
Outdoor area
B1-3: Indoor area 1,2,3
1:
Cold water drain
1a:
Infrared remote control
1b:
Room temperature controller
1c:
Cabled remote control
2:
Chiller
3:
Condensate drainage line
3a:
Condensate drainage line
(only units with HP-function)
4:
Condensate collecting drainage
5:
Medium outlet
6:
Medium inlet
REMKO KWE
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