HUMIFRIO FOG-SYSTEM

 

    It´s well known the fact that gas turbine power drops when air temperature increases.

   Gas Turbines are constant volume operating machines. When temperature increases, air is less dense; power output falls and decreases Gas Turbine performance, because the power output of a turbine depends on the flow of mass through it.

   Gas Turbine power output drops by 0.7-0.9% of its capacity for every 1°C rise in ambient temperature. During the central hours of the day, when energy demand is highest, the temperatures are too; this implies a decrease in its generation capacity. In addition, the increase in temperature raises the Heat Rate of the turbines; this implies that they need more gas to produce each kWh.

    For that reason, inlet air cooling has a high economic interest.

    Fogging is the most economic way to cool big air masses.

    The lowest temperature that can be obtained with fogging is the wet bulb temperature. And that would require the generation of a fog with micron size droplets, which are evaporated even at 100% of relative humidity. This technique allows 100% evaporation effectiveness so it's possible to attain 100 per cent relative humidity at the gas turbine inlet. The inlet air is, therefore, cooled to the ambient wet bulb temperature.

 

 

    Humifrio is the Spanish company, pioneer in turbine fogging.

    Humifrio is able to reach the maximum cooling thanks to the design of their installations, at 2000 psi (140 bars) operating pressure and using the best impaction pin nozzle.

    Cooling 14 ºC, achieved with fogging, you can assume an increase of 12.6 % of kWh generated during peak hours.

 

    A Humifrio´s client has supplied with the following chart. The blue line represents the Turbine power during 24 hours in an August day, the year before our fog installation. The red line shows the Turbine power an August day, but a year after, when our fog was installed. It is a real scenario of a turbine with upstream fogging installed

    In the scenario represented with the blue line, the maximum temperature for that day was 30 ºC and the minimum was 12 ºC, but the maximum inlet air temperature was 17 ºC.

    The Fog system is thermodynamically the world’s most cost-effective augmentation technology to return the turbine power loss and is the ideal system to improve the Heat Rate.