APPLICATION GUIDELINES
FRCC.PC.007.B5.02
29
SYSTEM DESIGN RECOMMENDATIONS
To obtain optimum effi ciency of the complete re-
frigerant system, optimised R410A heat exchang-
ers must be used. R410A refrigerant has good
heat transfer properties: it is worthwhile design-
ing specifi c heat exchangers to gain in size and
effi ciency.
An evaporator with optimised R410A distributor
and circuit will give correct superheat at outlet
and optimal use of the exchange surface. This is
critical for plate evaporators that have generally
a shorter circuit and a lower volume than shell &
tubes and air cooled coils.
For all evaporator types a special care is required
for superheat control leaving the evaporator and
oil return.
A sub-cooler circuit in the condenser that cre-
ates high sub cooling will increase effi ciency at
high condensing pressure. In R410A systems the
positive eff ect of sub cooling on system effi cien-
cy will be signifi cantly larger than in R22/R407C
systems.
Furthermore, for good operation of the expan-
sion device and to maintain good effi ciency in the
evaporator it is important to have a high degree
of liquid sub cooling. Without adequate sub cool-
ing, fl ash gas will be formed at the expansion de-
vice resulting in a high degree of vapour at the
evaporator inlet leading to low effi ciency.
Heat exchangers
Refrigerant charge limit Performer® SH compressors can tolerate liquid
refrigerant up to a certain extend without major
problems. However, excessive liquid refrigerant in
the compressor is always unfavourable for service
life. Besides, the installation cooling capacity may
be reduced because of the evaporation taking
place in the compressor and/or the suction line
instead of the evaporator. System design must be
such that the amount of liquid refrigerant in the
compressor is limited. In this respect, follow the
guidelines given in the section: “essential piping
design recommendations” in priority.
Use the tables below to quickly evaluate the re-
quired compressor protection in relation with the
system charge and the application.
When the condenser is mounted at a higher po-
sition than the compressor, a suitably sized «U»-
shaped trap close to the compressor is necessary
to prevent oil leaving the compressor from drain-
ing back to the discharge side of the compressor
during off cycle. The upper loop also helps avoid
condensed liquid refrigerant from draining back
to the compressor when stopped.
Discharge lines
HP
LP
Condenser
3D flexibility
U Trap
Upper loop
Model
Refrigerant charge limit
(kg)
SH090 5.9
SH105-120-140-161-184 7.9
SH180-240-300 13.5
SH380 14.5
To Next Page
Loading...
Need help?
General
