Thermal calculations + gas volume calculations
2. Calculation of the treatment time for a given heating output
3. Calculation of cooling requirement for room cooling with ceiling mounted fan and glycol operation
4. Calculation of the mixture temperature of two liquids
5. Gas volume calculations
Substance data: | Thermal capacity [kJ/(kgK)] | Density [kg/dm³(litre)] |
Water, 20°C | 4,1819 | 0,998234 |
Water, 100°C | 4,216 | 0,958382 |
Ethylene glykol (45%)-water | 3,33 | 1,055 |
Beer wort, 12°P (original wort), 10°C |
3,875 | 1,047 |
Drinking milk, 2.5% fat, 0°C | 3,83 | 1,0381725 |
Raw milk, 4.2% fat, 20°C | 3,9 | 1,029484768 |
Honey, liquid | 2,3 - 2,5 | ~1,4 |
Sugar, dissolved, 50%, 50°C | 3,119 | 1,215 |
Sugar, dissolved, 65%, 50°C | 2,779 | 1,302 |
Sugar, dissolved, 80%, 50°C | 2,372 | 1,396 |
Olive oil, 25°C | 1,858 | 0,887 |
Olive oil, 50°C | 1,936 | 0,875 |
Olive oil, 75°C | 2,015 | 0,863 |
Ethanol, 50%, 50°C | 3,934 | 0,889 |
Ethanol, 100%, 50°C | 2,718 | 0,729 |
For comparison: Aluminium | 0,896 | 2,699 |
Example 1 (batch heating):
5000 litres of water are to be heated up from 20°C to 30°C in a container within 30 minutes. The required thermal output must be calculated. An additional 30% must be included for absolute certainty.
- Liquid volume to be tempered: 5000 litres
- Thermal capacity: 4.1819 kJ/kgK
- Temperature difference: 10°K
- Heat loss: 30%
- Density: 0.998234 kg/dm³
- Time: 1800 seconds
Result: P = 151.05 kW
Example 2 (continuous "inline" process):
A heat exchanger is to be used to heat a volume flow of 150 hl/hour (1 hl = 100 litres) from 20°C to 30°C. The required thermal output must be calculated. An additional 40% must be included for absolute certainty.
- Volume flow: 15000 litres/h
- Thermal capacity: 4.1819 kJ/kgK
- Temperature difference: 10°K
- Heat loss: 40%
- Density: 0.998234 kg/dm³
- Time: 3600 seconds (as 150 hl flow per hour [3600s])
Result: P = 243.51 kW
How long does it take to heat a water volume of 5000 litres from 20°C to 30°C if the thermal output of the heater (or the heating surface in the tank wall) is 243 kW? An additional 40% must be included for absolute certainty.
- Volume flow: 5000 litres
- Thermal capacity: 4.1819 kJ/kgK
- Temperature difference: 10°K
- Heat loss: 40%
- Density: 0.998234 kg/dm³
- Heat output: 243 kW
Result: t = 1203 seconds
Substance data: | Heat transfer coefficient* U-value / k-value in kcal/m²h°C |
Concrete wall 25mm (not insulated) | 2,8 |
Insulated wall panels (PU foam), 10 cm | 0,3 |
Brick wall 24 cm | 1,3 |
Brick wall 12cm | 2,6 |
Insulated glass windows | 2,4 |
Wooden door (or boarded partition) | 3 |
*= The U values and the earlier k values can be assumed to be identical for
rough estimates
m1*c1*(t1-tm) = m2*c2*(tm-t2)
tm = ((m1*c1*t1)+(m2*c2*t2)) / ((m1*c1)+(m2*c2))
Substance data: | Thermal capacity [kJ/(kgK)] |
Water, 20°C | 4,1819 |
Water, 100°C | 4,216 |
Ethylene glycol (45%) water | 3,33 |
Beer wort, 12°P (original wort), 10°C | 3,875 |
Drinking milk, 2.5% fat, 0°C | 3,83 |
Raw milk, 4.2% fat, 20°C | 3,9 |
Warmer liquid | Colder liquid | |
Mass | m1 | m2 |
Thermal capacity | c1 | c2 |
Temperature | T1 |
T2 |