Cool Repair increases the technical availability of wind turbines

04/14/2020 12:51

Repairs of rotor blades are very dependent on the ambient weather conditions and the temperature. For financial reasons it is not possible to dismantle the blades and bring them into a protected environment.

Thus everybody has to wait for good weather to repair rotor blades. But furthermore, because of the common chemistry, it is not possible to work at low temperatures. That is why also DNV GL requires a relatively high minimum temperature of 16 °C for laminating works (DNVGL-ST-0376: Rotor blades for wind turbines). For many locations this means for several months a year the rotor can not have any service.

cp.max is no longer bound by this restriction. The DNV GL has tested the newly developed Cool Repair process and confirmed that it can be used from an ambient temperature of 6 ° C. In addition, it has been found to provide outstanding quality over traditional hand lay-up (Certificate: SA-DNVGL-SE-0436-04624-1).

The core of the Cool Repair process is a heat-vacuum-hood, which is placed directly on the repair site and adheres independently. By means of an intelligent regulation, the laminate is supplied with exactly the necessary heat. The temperature profile is recorded digitally. Furthermore the repair materials are compressed by the vacuum pressure.


Scheme of the heatable vacuum hood


An important advantage of the process: the common repair materials stay the same. No resin system, no fabrics and no tools need to be changed.

In addition to better control of the repair quality, Cool Repair primarily enables the extension of the repair period. Depending on the climatic conditions at the location, work can be extended by about one month at the beginning of winter. For example, the repair season would not end in October, but in November. And in spring, work can start again earlier.

This means an enormous logistical and economic advantage for repairs in regions with a cool winter. Operators and turbine owner can benefit directly from the higher availability of their wind farm.


Cool Repair was developed together with the Süddeutsche Kunststoffzentrum as part of the Central Innovation Program for SMEs.

Kooperationspartner und Förderer des Projektes


The vacuum hood adheres independently on the blade
The thermal image of the hood shows the homogeneous temperature distribution

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