VeraciousTech https://veracioustechs.com/

Calorifier Heating Capacity Calculator

Use this Calorifier Heating Capacity Calculator to estimate the heating capacity (kW) required to reheat a calorifier's stored volume within a given recovery time.

Input Parameters

Litres

°C

°C

Hours

%

Calculation Results

Temperature Rise — °C
Energy Required — kWh
Required Heating Capacity — kW
Recommended Heater Capacity — kW

Calculation Formulas
  • ΔT = Storage Temperature − Cold Water Temperature
  • Energy = Volume × 4.186 × ΔT / 3600
  • Heating Capacity = Energy ÷ Recovery Time ÷ Efficiency

The value 4.186 is the approximate specific heat capacity of water in kJ/kg·°C. Dividing by 3600 converts kJ to kWh, and efficiency is applied as a decimal (e.g. 90% = 0.90).

How to Use This Calculator

  1. Enter the storage volume of the calorifier.
  2. Enter the cold water and storage temperatures.
  3. Set the required recovery time to reheat the full volume.
  4. Enter the system efficiency.
  5. Review the required heating capacity and download a PDF report.

Frequently Asked Questions

How do I calculate calorifier heating capacity?
Work out the energy needed to raise the stored volume through the temperature rise, then divide by the recovery time and the system efficiency to get the heating capacity in kW.
What is temperature rise?
It is the difference between the hot water storage temperature and the incoming cold water temperature, i.e. how many degrees the water must be heated.
Why does efficiency matter?
Some heat is always lost in the heat exchanger and pipework. Dividing by efficiency increases the required capacity so the recovery time is still achieved in practice.
How is energy converted to kWh?
Energy in kJ is divided by 3600 because there are 3600 kilojoules in one kilowatt-hour.
Why is the heater size rounded up?
Heaters and heat exchangers come in standard ratings, so the calculated figure is rounded up to the next practical size.

Results are estimates based on the values entered and the calculation method shown. Actual system requirements may vary depending on operating conditions, demand patterns, equipment configuration and applicable project requirements.