Organic Rankine Cycle Power Calculator

Use our online calculator to estimate the electric and thermal power that can be retrieved from your heat source using an ORC Turbogenerator. You will get both the theoretical and the real cycle efficiency, taking into account real world factors such as mechanical losses, heat losses, etc.
Please keep in mind that these are only estimates. They can be useful to get a rough idea, but in reality things can differ significantly from case to case. To have a more precise evaluation please contact our sales engineers. They will be happy to conduct a deeper analysis on your specific case.

Start the calculation.

Step 1 of 3

Which kind of heat source do you have?

Step 2 of 3

Drag to select inlet temperature before heat exchange (on the right)
and outlet temperature after heat exchange (on the left)
flow rate

Step 2 of 3

How much biomass is available to be burnt?
Drag and release to choose value
* operating hours at full load = 8000 hours/year
* boiler efficiency= 0.85
* a thermal oil loop is used to exploit this source, with inlet/outlet temperatures of 310 - 250 °C
Do you know the Low Heating value of your Biomass?

Drag to Choose the Low Heating Value of your Biomass

Do you know the percentage of water content of your Biomass?

Drag to Choose the Low Water Content of your Biomass
The low heating value is evaluated assuming a higher heating value equal to 5 kWh/kg.
For this simulation we will assume a default Low Heating Value of 2.5 kWh/Kg

Step 3 of 3

Choose a cold source for the heat produced by your plant:
Drag to select the inlet temperature of the cooling fluid before heat exchange (on the left)
and the outlet temperature of the cooling fluid after heat exchange (on the right)
Note: if you have selected air (no thermal use) as the cooling fluid, we suggest you use the annual mean temperature of the source site as the inlet temperature and the annual mean temperature+10-12°C (or equivalent) as outlet temperature


Power Results

  • Net electric power (kW):
  • Mechanical power (kW):
  • Thermal power to the condenser (kW):
Note: a generator efficiency of 0.96 is assumed - the net electric power is calculated including ORC fluid pump but excluding hot source or cold source pumps/fans, if any.
Turboden does not produce units under 200 kW net electric power.

Heat Power:

  • Your Source has a thermal power of around kW:

Theoretical Cycle Results:

  • Lorenz cycle efficiency (infinite exchange area):
  • Lorenz cycle efficiency (finite exchange area):
  • Real cycle efficiency:
Assumptions ΔT constant for finite heat exchange area:
* ΔTpreheater + evaporator = 15 K
* ΔTcondenser = 10 K

For biomass, Lorenz Cycle efficiency is calculated with the thermal oil inlet/outlet temperature

Real efficiency to Lorenz efficiency ratio (finite exchange area)
* X=0.5

Thermal Power - temperature diagram

  • The diagram shows heat source and cooling source temperature variation along power exchange.

Temperature (°C)

Power (kW)

Yellow: Heat Source, thermal oil in case of Biomass
Red: working fluid, hot side
Green: working fluid, cold side
Blue: cooling fluid


You can restart the calculation to input different values, or you can contact our sales engineers to have a more specific evaluation of your case.

To know more about this calculation, you can read our calculation procedure

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