Airedale EcoChill 6kW - 46kW - Manual (Page 53)

53 EcoChill Installation Manual 7481930_v1.6.0_08_2013
ECL-ECLH 020-202
EN
12. ETHYLENE GLYCOL SOLUTION
• The correction factors for cooling capacity and
power input take into account the presence of
glycol and the different evaporating tempera-
tures.
• The correction factor for pressure drop takes
into account the different flow rates derived
from the application of the correction factor for
flow rates.
• The correction factor for water flow rate is
calculated to maintain the same ∆t that would
be without glycol.
NOTE:
To understand how to read the diagram an example is
given below.
Using the diagram the necessary percentage of glycol
can be determined, taking into consideration one of the
two following factors:
Based on the fluid considered (water or air) enter the
diagram from the right or the left and intersect the
leaving water temperature or external air temperature
curve and draw a vertical line from this point to identify
the glycol percentage and the relative correction fac-
tors.
11.3. HOW TO READ THE DIAGRAM
The curves shown on the diagram summarise a large
quantity of data, with each curve representing a par-
ticular function, for whose correct understanding it is
necessary to make certain initial considerations:
In case the percentage glycol required is based on
external air temperature enter the diagram horizontal-
ly from the left to intersect the curve and draw a verti-
cal line through this point. The intersections with the
curves above present the correction factors for cooling
capacity, power input, pressure drop and flow rate (the
correction factors are applied to the nominal perfor-
mance data of the unit size in consideration). The inter-
section with the curve below gives the recommended
percentage of glycol for the external air temperature.
In case the percentage glycol required is based on the
leaving liquid temperature enter the diagram horizon-
tally from the right to intersect the curve and draw a
vertical line through this point. The intersections with
the curves above present the correction factors for
cooling capacity, power input, pressure drop and flow
rate (the correction factors are applied to the nominal
performance data of the unit size in consideration).
The intersection with the curve below gives the rec-
ommended percentage of glycol for the leaving liquid
temperature.
It is reminded that the initial parameters of "EXTER-
NAL AIR TEMPERATURE" and "LEAVING LIQUID
TEMPERATURE" are not linked with each other
so it is not possible to enter the diagram from one
parameter to determine the corresponding value of
the other.
2.20
2.10
2.00
1.90
1.80
1.70
1.60
1.50
1.40
1.30
1.20
1.10
1.00
0.99
0.98
0.97
0.96
0.95
0.94
5
0
-5
-10
-15
-20
-25
-30
-35
-40
0 5 10 15 20 25 30 35 40 45 50 55
-6
0
5
Pc
Ph
Qw (2)
Qw (1)
∆P (5)
∆P (4)
∆P (3)
∆P (2)
∆P (1)
Pe
LE
AVING
LIQUID
TEMPERA
TURE
EXTERN
AL
AIR
TEMPERA
TURE
Glycol %
Corr
ection f
act
or
s
LEGEND:
Pc Correction factor cooling capacity
Pe Correction factor power input
Ph Correction factor heating capacity
ΔP (1) Correction factor pressure drop with average fluid temperature = -3.5 °C
ΔP (2) Correction factor pressure drop with average fluid temperature = 0.5 °C
ΔP (3) Correction factor pressure drop with average fluid temperature = 5.5 °C
ΔP (4) Correction factor pressure drop with average fluid temperature = 9.5 °C
ΔP (5) Correction factor pressure drop with average fluid temperature = 47.5 °C
Qw (1) Correction factor flow rate (evaporator) with average fluid temperature = 9.5 °C
Qw (2) Correction factor flow rate (condenser) with average fluid temperature = 47.5 °C
NOTE
Although the diagram goes down to external air temperatures of -40 °C refer to the operating limits of
the unit.