11
20
25
30
35
40
45
50
55
60
Twe °C
25
30
35
40
45
50
55
60
65
Tc
Twc
-6 -4 -2 0 2 4 6 8 10 12 14 16
6 CRITERIA OF CHOICE
6.1 FUNCTIONING LIMITS
1
2
6.2 DESIGN DATA
High pressure
side
Low pressure side
Maximum acceptable pressure bar 28 22
Maximum acceptable temperature °C 120 52
Minimum acceptable temperature °C -10 -16
1
Functioning with glycoled water
2 Standard functioning
NOTE
Twe
Heat exchanger output temperature
with (evaporator) functioning
Twc
Heat exchanger output temperature
with (condenser) functioning
Tc Condensation temperature
The functioning limits diagram is relative
to a ∆t of 5 °C on the evaporator and
on the condenser (for the units with
condenser).
7.1 COOLING CAPACITY AND
ABSORBED POWER
The cooling capacity produced and the
electrical power absorbed in conditions
different to nominal conditions are
obtained by multipling the nominal values
(Pf, Pa) by the respective corrective
co-efficients (Cf, Ca).
The following diagram allows to
obtain the correct co-efficients to be
used for chillers in cooling mode; in
correspondence of each curve the
temperature of the water exiting the
condenser is stated, to which reference
is made (∆t=5°C is assumed).
KEY:
Cf = Corrective co-efficiency of the
cooling capacity
Ca = Corrective co-efficiency of the
absorbed power
NOTE:
FOR ∆T DIFFERENT TO 5°C
At the evaporator Tab.7.3 is used to
obtain the corrective powers of the
cooling capacity and power absorbed.
In order to consider dirtying of the
heat exchangers, relative dirtying
factors are used.
~~~~~~~~
µ:
~
~~
~
~
~
~
~~~~~~~~
µ:
~
~~
~
~
~
~
7 CORRECTIVE CO-EFFICIENTS
Temperature of the water produced (∆t=5°C)
Water temperature exiting
condenser
Cf
Ca
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