Trane LIFT 81-P - Position of Connections; Hydraulic Data

4 | Water connections
15
For the process application a 50% higher water content is
recommended to stabilize the outlet temperature (1.5 x M
calculated with the previous formulas).
ΔP Pressure drops in kPa
V
Water flow rate in mc/h
4.2 Position of connections
The position of the water connections and the inlet and outlet
direction is indicated by the labels on the connections.
4.3 Hydraulic data
4.3.1 Water volume
The machine electronic control, to protect the electrical motor, limits
hourly start up of the compressor.
This operation creates oscillations of the water temperature in the
draw-off point, affecting plant efficiency.
For a correct operation, the water volume must comply with the
following formula:
M > 9,45 x k x n/N x (Qf - q)
M = Minimum water content (I);
k = Factor that takes into account the different water temperature
value between the inlet and outlet of the evaporator or condenser;
n = Partialisation coefficient (n = 1 unit up to 4 compressors; n = 2
units with more than 4 compressors);
N = N. of compressors;
Qf = Cooling power or heating power (kW);
q = Permanent thermal load in the system (kW), (q = 0 if the value is
unknown).
ΔT (K) K
3 1
4 1
5 1
6 1.05
7 1.10
8 1.15
9
1.20
10
1.25
4.3.2 Water features
Water features are important for the proper operation of the machine
and for its lifetime.
Extreme water hardness leads to the formation of limestone in
exchangers reducing their performance.
The table shows some water parameters to be observed for proper
operation of the machine.
Content
Concentrati
on mg/l or
ppm
Material
AISI 316L
Copper
pH
<6
2
2
6-7.5
2
2
7.5-9
1
1
>9
1
2
Alkalinity
HCO3
- <70
1
2
70-300
1
1
>300
1
2
Sulphate
SO42-
<70
1
1
70-300
1
3
>300
1
3
Alkalinity/Su
lphate
HCO3-/SO42-
>1
1
1
<1
1
3
Electrical
conductivity
μS/cm
<10
1
2
10-500
1
1
>500
1
2
Ammonium
NH4
<2
1
1
2-20
1
2
>20
1
3
Free
chlorine
Cl2
<1
1
1
1-5
3
1
>5
3
3
Hydrogen
Sulphide
H2S
<0.05
1
1
>0.05
1
3
Free Carbon
Dioxide
CO2
<5
1
1
5-20
1
2
>20
1
3
Nitrate
NO3
<100
1
1
>100
1
2
Iron
Fe
<0.2
1
1
>0.2
1
2
Aluminium
AL
<0.2
1
1
>0.2
1
2
Manganese
MN
<0.1
1
1
>0.1
1
2
1 - Good corrosion resistance.
2 - If different factors of this type are present, corrosion can occur.
3 - Use not recommended.
4.3.3 Protection against freezing
If you do not wish to drain the system during periods where the
machine is not used, the water may freeze, or if the system must
operate with temperatures less than 5°C, ethylene glycol must be
mixed with the water.