Water Heating Calculator

Calculate energy required and time needed to heat water through different phases

Calculate Water Heating Energy

Amount of water to heat (1L water = 1kg)

Starting temperature of water

Target temperature of water

W

Power of heating device (e.g., 1800W for kettles)

%

Heating efficiency (typically 80-95%)

Energy Calculation Results

335.2
kJ (kilojoules)
93.11
kWh (kilowatt-hours)
80.1
kcal (calories)

Energy Breakdown by Phase

Water Heating
Heat water from 20.0°C to 100.0°C
335.2 kJ
100.0%

Heating Time

3m 26s
Using 1800W at 90% efficiency
Effective power: 1620W
Total time: 207 seconds

Example: Heating Ice to Steam

Problem: Heat 1 kg of ice from -10°C to 110°C

Initial state: 1 kg ice at -10°C

Final state: 1 kg steam at 110°C

Phases involved: Ice heating → Melting → Water heating → Vaporization → Steam heating

Calculation Steps

1. Ice heating: 1 kg × 2108 J/(kg·°C) × 10°C = 21,080 J

2. Ice melting: 1 kg × 334,000 J/kg = 334,000 J

3. Water heating: 1 kg × 4190 J/(kg·°C) × 100°C = 419,000 J

4. Vaporization: 1 kg × 2,264,705 J/kg = 2,264,705 J

5. Steam heating: 1 kg × 1996 J/(kg·°C) × 10°C = 19,960 J

Total energy: 3,058,745 J = 3,059 kJ

Heat Transfer Methods

1

Conduction

Direct contact heat transfer

Pan on stove, ice in hand

2

Convection

Heat transfer through fluid motion

Boiling water, air circulation

3

Radiation

Electromagnetic wave transfer

Sun's heat, microwave oven

Physical Constants

Specific heat (ice):2,108 J/(kg·°C)
Specific heat (water):4,190 J/(kg·°C)
Specific heat (steam):1,996 J/(kg·°C)
Latent heat (fusion):334,000 J/kg
Latent heat (vaporization):2,264,705 J/kg

Water Heating Tips

💡

Water has high specific heat capacity due to hydrogen bonding

💡

Phase changes require latent heat without temperature change

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Heating efficiency depends on device and insulation

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1 liter of water weighs approximately 1 kg

Understanding Water Heating Physics

Heat vs. Temperature

Heat is energy that transfers due to temperature differences, measured in Joules (J). Temperature measures the average kinetic energy of molecules, measured in degrees.

Specific Heat Capacity

The amount of heat required to raise the temperature of 1 kg of a substance by 1°C. Water has a high specific heat capacity (4,190 J/(kg·°C)) due to hydrogen bonding.

Sensible Heat Formula

Q = m × c × ΔT

  • Q: Heat energy (J)
  • m: Mass (kg)
  • c: Specific heat capacity (J/(kg·°C))
  • ΔT: Temperature change (°C)

Latent Heat

Energy required for phase changes without temperature change. Ice melting and water vaporization require significant energy to break molecular bonds.

Latent Heat Formula

Q = m × L

  • Q: Heat energy (J)
  • m: Mass (kg)
  • L: Latent heat (J/kg)

Heating Time

time = Qtotal / (efficiency × power)