COOLER
SELECTION
Designation:
PV = Power loss [kW]
P01 = Specific cooling capacity [kW/°C]
V = Tank contents [l]
ρoil = Density of the oil [kg/l]
for mineral oil: 0.915 kg/l
Coil = Specific heat capacity [kJ/kgK]
for mineral oil 1.88 kJ/kgK
?T = Temperature increase in the
system [°C]
t = Operating time [min]
T1 = Desired oil temperature [°C]
T3 = Ambient temperature [°C]
Example 1:
Measurement of the power loss
on existing units and machinery.
For this method the temperature
increase of the oil is measured
over a certain period. The power
loss can be calculated from the
temperature increase.
Parameters:
The oil temperature increases
from 20 °C to 45 °C over
15 minutes.
The tank contains 100 l.
Heat to be dissipated:
PV =（?T × C oil × ρoil × V）/t × 60 [kW]
PV =25 × 1.88 × 0.915 × 100 / (15 × 60 )
= 4.78 [kW]
Cooler selection:
– Desired oil temperature: 60 °C
– Ambient temperature air: 30 °C
P01 =PV /(T1 - T3) [kW/°C] =0.159
A 10% safety margin is
recommended to allow for
element contamination, and
therefore the specific power is:
P01 × 1.1 = 0.175 kW/°C.
The power loss 0.175 kW/°C must
be dissipated by an oil cooler.
Suggestion:
–Cooler OK-ELH2 - 3000 rpm,
P01 = 0.20 kW/°C at 80 l/min
我发了一段在上面！ |
发表于 2013-11-17 11:41:24
