Julabo
Determination
of Heating/Cooling Power |
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The following is the
general formula for determining necessary heating and cooling
requirements of a system.
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| Formula:
Q=mC(T2-T1)/t
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where:
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m=
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mass
of bath/reactor fluid |
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C=
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specific
heat of bath/reactor fluid |
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T1=
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start
temperature |
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T2= |
end
temperature |
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t= |
elapsed
time |
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| Directions:
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Please
substitute your own values as indicated below. |
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Value
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| 1
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20
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liters |
Enter
the volume of the circulator + hoses + reactor jacket volume
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| 2
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0
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liters
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Enter
the volume of the reactor (enter zero if not applicable)
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| 3
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1
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kg/liter
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Enter
the density of the circulator bath fluid |
| 4
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0
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kg/liter
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Enter
the density of the reactor fluid (enter zero if not applicable)
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| 5
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1.45
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kJ/(kg°C)
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Enter
the specific heat capacity of the circulator bath fluid
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| 6
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0
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kJ/(kg°C)
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Enter
the specific heat capacity of the reactor fluid (zero if not
applicable) |
| 7
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120
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°C
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Enter
the starting temperature
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| 8
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-10
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°C
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Enter
the target temperature |
| 9
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14000
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seconds
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Enter
the desired heat-up/cool-down time
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| 10
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kW
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Enter
estimated power losses (this number must
be positive) |
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Bath
Liquid Properties |
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| Value |
m1(kg)
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| 11
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20
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Multiply
value 1 times value 3 and enter result here |
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C1
(kJ/[kg°C]) |
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12
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1.45
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Enter
value 5 here |
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Reference
Data |
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Reactor
Liquid Properties |
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Specific
Heat |
Density
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m2
(kg) |
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kJ/(kg°C)
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kg/liter
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| 13
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Multiply
value 2 times value 4 and enter result here |
water
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4.18 |
1 |
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ethanol
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2.43
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0.783
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C2
(kJ/[kg°C]) |
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methanol
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2.49
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0.787
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| 14
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Enter
value 6 here |
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silicon
oil |
1.45
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1
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aluminum
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0.896
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2.7
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Customer
Requirements |
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copper
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0.385
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8.9
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Value
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t
(s) |
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iron
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0.45
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7.84
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15
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14000
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Enter
value 9 here |
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lead
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0.128
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11.31
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silver
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0.235
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10.47
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T1
(°C) |
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tin
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0.217
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5.73
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16
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120
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Enter
value 7 here |
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ammonia
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4.8
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0.602
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mercury
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0.139
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13.56
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T2
(°C) |
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50/50
EG/H20 |
3.25
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1.1
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17
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-10
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Enter
value 8 here |
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Required
Heating/Cooling Power |
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Modified
Equation: |
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Q=[(m1C1)+(m2C2)][(DT)/t]
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Temperature
Change |
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Value
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DT
(°C) |
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18
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-130
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Subtract
value 16 from value 17 and enter result here |
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19
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Nominal
Heat Load (kW) |
Nominal
Heat Load is the calculated load based on the customer's requirements.
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-0.269
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Perform
the following calculation:
[(v11v12)+(v13v14)][(v18)/v15] |
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20
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Total
Heat Load (kW) |
Total
Heat Load is the Nominal Heat Load plus any estimated losses.
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-0.269
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If
value 19 is positive, add value 10.
If value 19 is negative, subtract value 10. |
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Heating
or Cooling? |
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20
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Cooling!
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If
value 19 is positive, heating is required.
If value is negative, cooling is required. |
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| Important
Note: This
calculation should only be used as a basis for circulator/chiller
selection. Many
factors that will influence power requirements are too difficult
to quantify, and thus are neglected from this calculation. Actual power requirements will almost always be larger than
calculated values. |
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Additional
Notes: |
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1
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Julabo
is not responsible for damages/injuries caused by using unapproved
bath fluids in circulators/baths/chillers. |
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2
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Julabo
is not responsible for damages/injuries resulting from incorrect
use of approved bath fluids. |
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3
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Flash
points of bath fluids must be above +60°C for transport by plane.
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4
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Julabo
chiller/circulator high temperature warning and safety values
should reference fluid flash temperature. |
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5
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Julabo
chiller/circulator low temperature warning should reference
fluid freezing point or maximum viscosity. |
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6
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Julabo
H350 bath oil is intended only for
Julabo high temperature sealed systems. |
