SMC Networks HECR Series Manual page 7

Guide to Model Selection
Example 2 When the heat generation amount in the user's equipment is not known.
Obtain the temperature difference between inlet and outlet by circulating the fluid inside the user's equipment.
Heat generation amount Q
Circulating fluid temperature difference ΔT (= T2 – T1)
Circulating fluid outlet temperature T1
Circulating fluid return temperature T2
Circulating fluid flow rate L
Circulating fluid
γ
ΔT x L x
x C
Q =
60 x 1000
0.8 x 3 x 1 x 10
=
60 x 1000
= 167 W
Cooling capacity = Considering a safety factor of 20 %,
167 W x 1.2 =
Example 3 When cooling the object below a certain temperature in certain period of time.
Cooled substance total volume V
Cooling time h
Cooling temperature difference ΔT
Circulating fluid
∗ Refer to the information shown below for the typical
physical property values by circulating fluid.
γ
ΔT x V x
x C
Q =
h x 60 x 1000
3
10 x 2 x 1 x 10
=
15 x 60 x 1000
= 93.3 W
Cooling capacity = Considering a safety factor of 20 %,
93.3 W x 1.2 = 112 W
Precautions on Model Selection
The flow rate of the circulating fluid depends on the pressure loss of the user's equipment and the length, diameter and
resistance created by bends in the circulating fluid piping etc. Check if the required flow rate of circulating fluid can be
obtained before selecting.
Circulating Fluid Typical Physical Property Values
Ethylene Glycol Solution 20 %
Temperature [°C]
10
20
30
40
50
60
Water
Density γ: 1 x 10
3
[kg/m
: Unknown
: 0.8 °C (0.8 K)
: 25 °C (298.15 K)
: 25.8 °C (298.95 K)
: 3 l/min
: Water
Density γ : 1 x 10
Specific heat C: 4.2 x 10
3 3
x 4.2 x 10
200 W
: 2 L
: 15 min
: Temperature difference: 10 °C (10 K). Cool from 30 °C (303 K) to 20 °C (293 K).
: Tap water
Density γ : 1 x 10
3
Specific heat C: 4.2 x 10
3
x 4.2 x 10
Density ρ [kg/m 3
]
3
1.03 x 10
3
1.03 x 10
3
1.02 x 10
3
1.02 x 10
3
1.01 x 10
3
1.01 x 10
3
] Specific heat C: 4.2 x 10
Model Selection
3 3
kg/m
3
J/(kg·K)
Circulating device
3
kg/m
3 J/(kg·K)
Specifi c heat C [J/(kg·K)]
3
3.93 x 10
3
3.95 x 10
3
3.97 x 10
3
3.98 x 10
3
4.00 x 10
3
4.02 x 10
3
[J/(kg K)]
•
Series
T2: Return temperature
L
T = T2 – T1
T1: Outlet temperature
Water bath
20 °C
After 15 min, cool 30 °C down to 20 °C.
HECR
User's equipment
V
6