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Circulators, Heaters
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Water Heating Time Calculations
The specific heat of water is 4.186 J/g°C
The equation for calculating the needed energy value for a certain water heating process is:
Q=c*m*(dT)
c-specific heat (J/g°K) of the heated liquid
m- the mass of the liquid that needs to be heated (g)
dT- temperature difference during the process (°K)
Q- needed amount of energy for the process (J)
For example: In order to heat up 200L of water from 45°C to 90°C, we'll use the equation
above:
Q = 4.186 J/g K *200,000g * 45K = 37,674,000J
Conversion of the energy (Q) to power (P): 1 Watt=1 J/s
Thus, in order to calculate the time needed for the process (given a heating element of
2000W power) :
t(s)=Q/P
time=37,674,000J/2000(J/s)=18,837s=313.95min=5.23h=05:14:00
Meaning, it takes about 5 hours to heat up 200L of water from 45°C to 90°C with 2000W
heating power.
A few examples of the time needed to heat up various volumes of water in different
powers:
Assumptions: Optimal contiditions, no heat is lost to the environment, full conversion of the
heating element's voltage into heat.
If we were to increase the power twice- the heating time will shorten in half for the same
volume, and so on.
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