Fisair systems reduce steam turbine natural cold downtime by 40%, with a significant saving in staff time and maintenance.

They provide high starting flexibility, so the plant is operational again in a short space of time.

The Super Dryer has 2 main functions:

  • Forced cooling
  • Advance preservation

As well as using it for the turbine, its portability means it can be used for preservation the elements that appear in the following graphic.

Super Dryer: equipment that allows forced cooling and advanced preservation

Following the boom in renewable energy, energy prices began to rise considerably and many plants could not compete due to the high stop and start times. In response to this problem with renewable energy, we began developing high pressure equipment that no other supplier had developed.

These devices reduced the number of dryers to connect as well as downtime. We worked with power plants and their technicians to solve a problem for turbine manufacturers at their request. There was no such technology on the market, so FISAIR became a pioneer in developing it.

FISAIR has been working with the most important turbine manufacturers for 3 years to develop the Super Dryer, to develop equipment that performs both functions: forced cooling and advanced preservation.

We have standardised the connection to your turbine for simplicity.

The equipment was designed within a rack framework, for easy connection to the turbine and easy movement.

Equipment with these features is usually specified in new plants, due to their great advantages.


DFRC-0500E PLUS desiccant rotor air dehumidifiers

This product can be operated with any steam turbine.

Modifications can be made according to the project to comply with final customer specifications.

All details are analysed in each of the projects.


Forced Cooling and Advanced Preservation System

How it works to shorten cooling time after shutdown

The task of the forced cooling fan rack is to supply cooling air to the steam turbine to shorten the cooling time after shutdown.

The cooling air is fed to the steam turbine through connections located in the condenser (vacuum breaker) and the HP housing balance flange (hole) – or the cold reheat section upstream of the retention valve assisted by the HP turbine exhaust. The pressurised air (cooling air) is blown through flexible hoses in these two openings with mobile external equipment subject to this specification.

The cooling air flows back through the LP, IP and HP turbine to the common vent connection in the cold reheat steam system and released to the atmosphere.

In addition, the equipment must be able to function as a mobile dehydrating vent with an absorption component (air dryer) and accessories (e.g. manifold, slide valve and spiral hoses with hose connections) as preservation equipment.

The dehumidification and reconditioning processes in the absorption component must be continuous. The wet reconditioning air must be led to the atmosphere in such a way that it cannot be sucked back into the drying or reconditioning air inlet.

Forced cooling is only active until the average temperature of the HP and IP rotor reaches 150°C, the operation of the Blower & Super Dryer rack is independent of the turbine control system and can be turned on and off from the local plate in the rack.

Software modifications will be implemented in the control system in the next C-inspection or in a planned plant shutdown. The same applies at a distance: Hardware modification away from the reheat connection tubing.

After restoring the power plant (excluding GT), the Super Dryer and blower can be used to preserve the ST, WSC and HRSG to be ready from the start. This system can also be installed for preservation reasons only.

Benefits of the Forced Cooling Equipment

  1. Quick installation of cooling equipment with a minimum of personnel. Easy transport systems to the temporary location.
  2. Up to 40-50% reduction in cooling time from the ST strip.
  3. Cooling assured and monitored for the steam turbine.
  4. Overall reduction in downtime for inspection, revision or repair, whether maintenance is planned or not.
  5. Cooling air flows in the opposite direction to the steam flow in operation to maintain thermal stress and minimise consumption time.
  6. Forced cooling with steam (preparation time) not needed before shutdown; this also reduces unnecessary rotor compression effort.
  7. Reduction in the number of preservation systems to a single component for the entire circuit.
  8. Proportional humidity control by solid state relay in reactivation and flow through integrated frequency inverter.
  9. Circuit components can be maintained can be maintained.
  10. Preserved systems include the HP/IP/LP steam turbine, condenser and the boiler.

Extending the operational life of the plant with Super Dryer

    • Natural cooling time reduced by 50% (not incl ST B/C-Insp).
    • Maintenance of ST systems, if necessary, is possible during the GT A/B-Insp.
    • ST can be isolated completely after the cooling is completed.
    • Implementation of Super Dryer is possible during a GT A/B/C-Insp.
    • Benefits for the engineer for the start-up phase. Benefits for engineer’s start-up tasks (less work and time) during ST B/C-Insp.

    • Preservation Mode includes ST HP/IP/LP, Condenser, WSC and Boiler Reheater.
    • Equipment manufacture and delivery period very short (2-4 months).
    • No additional drainage for water steam cycle, apart from procedures also applicable for normal shutdown; same start-up time after inspections A and B.
    • Easier for customer to accept and have product released within its maintenance budget.
    • Equipment is light and mobile to be moved around the plant for standard preservation of other equipment, such as HRSG, Condenser, Gas Tubes and Tubing.

Why choose Fisair for thermal power plants

Fisair is committed to a high quality product, which also includes the following services:

  • Equipment rental
  • Replacements parts
  • Technical assistance
  • Advice
  • Warranty extension
  • Training

Success Cases

Equipment with forced cooling has been supplied successfully in several places around the world, complying with the rigorous standards of turbine manufacturers in each.

USA, Birdsboro

UK, Carrington


ISRAEL, Tzfat/Ashalim

GERMANY, Manheim



Application References

Some outstanding references:

    • Gas Natural Fenosa
    • Alstom
    • General Electric
    • AAF
    • Endesa
    • Iberdrola
    • Vantaan Energía
    • Amec Foster Wheeler
    • Rolls-Royce
    • Enel

Our locations


Phone: +1 (413) 347 3303


Phone: +44 (0) 330 1137949


Phone: +52 221 120 5406


Phone: +34 91 723 38 40


Phone: +49 6081 9665324


Phone: +33 240 953 839


Phone: +54 911 6366 0012


Phone: +34 917 23 3840