T-CU19-JAN24-1
Page 9
Application Guidelines
Condensing Unit Selection
Selection of the correct size of inverter condensing unit as
method below:
Select a condensing unit size which achieves the peak load
system cooling capacity demand at its maximum speed.
It should ensure that the condensing unit
capacity at minimum speed (30rps) is not
higher than the necessary cooling capacity for
the smallest evaporator in the system. Failure
to meet this criterion will cause condensing
unit work outside its application envelope and as
consequence reduce lifetime.
Example (R448A, Evaporating temperature: -10
0
C,
Ambient temperature 32
0
C):
Evaporator 1: 5kW
Evaporator 2: 3kW
Evaporator 3: 2.6kW
Evaporator 4: 2.5kW
Total maximum cooling capacity = 13.1kW
Minimum cooling capacity = minimum evaporator capacity
= 2.5kW
According to the capacities R448A at Te = -10
0
C, Ta
=32
0
C, condensing unit JEHSI-066-B4-M-3 (maximum
capacity 13.2kW and minimum capacity 5.0kW)
Condensing unit maximum capacity 13.2kW achieves the
peak load system cooling capacity 13.1kW but minimum
speed 30rps which deliver minimum capacity exceed the
necessary cooling capacity for the smallest evaporator
(2.5kW).
In above case, it is recommended to connect few
evaporators together (regulated by one thermostat) to
achieve smallest required capacity higher than the minimum
capacity of the condensing unit: by connecting Evaporator 3
and Evaporator 4 via one common thermostat (2.6kW +
2.5kW = 5.1kW), which is higher than the minimum
capacity of the condensing unit (5.0kW)
Table 7: Compressor Speed Range
Indicator:
rps: revolution per second of motor shaft (rotor)
rpm: revolution per minute of motor shaft (rotor)
rps = rpm / 60
Suction line shall be insulated to avoid:
•
High superheat during high ambient condition can
create high discharge temperature.
•
Too low superheat during low ambient condition that
can condense refrigerant inside suction line.
Table 8: Operating Limit
Operating Limits
Recommendation
Discharge gas
temperature
110
0
C maximum
Evaporator outlet
superheat
Above 6K (to avoid liquid flood
back)
Suction gas
superheat at
compressor inlet
Not more than 20K
Voltage supply
Min: 360V, Max: 440V
Phase asymmetry
+/- 3%
Frequency
50Hz +/- 1%
Outdoor ambient
Min: -15
0
C, Max: 43
0
C
Compressor
The scroll compressor inside Daikin inverter
condensing unit is a high-pressure dome
compressor, with 6 poles brushless DC
motor (BLDCM). The compressor cannot
operate without the frequency converter. It
will be destroyed immediately if connected directly to the
public network.
The pressure inside the shell of compressor is a high
(discharge) pressure and have high temperature. Care must
be taken when orientating the power supply cables to the
main isolator. Never touch the power supply cable to the
body of compressor, unless heat resistant cables are used.
Health and Safety
Daikin inverter condensing unit must be
installed and commissioned by competent
personnel, who are familiar with refrigeration
systems and components including all controls.
To avoid potential injury, use care when
working around coil surfaces or sharp edges of metal
cabinets. All piping and electrical wiring should be installed
in accordance with all applicable standards and local laws.
General Information
Before Installation
•
Ensure the units received are the correct models for the
intended application.
•
Ensure the refrigerant, electrical supply and maximum
working pressure are all suitable for the proposed
application.
•
Check there is no damage to the units. Any damage
should be reported to the supplier immediately.
•
Check that the proposed equipment locations are
suitable and provide adequate support for the weight
of the units.
Offloading and Lifting
•
Whenever a condensing unit is lifted, it should be from
the base and, where possible, all packing and
protection is kept in position.
•
If lifting equipment is required, ensure that it is suitable,
certificated, and that the operators are qualified to
use it.
Compressor speed
Minimum
Maximum
rps
30
100
rpm
1800
6000
