The Fog Engineers H.Ikeuchi & Co.,LTD

Gas Turbine Inlet Air Cooling System

Product outline

It is generally observed that power output of a gas turbine, which intakes ambient air and utilize it to power the turbine, decreases in summer. One of the approaches to counteract this problem is our gas turbine inlet air cooling system. This system makes use of the heat of vaporization as fog evaporates, which effectively lowers the temperature of the inlet air taken in to the duct, increases its density, and restores the power output during the summer.

Our gas turbine inlet air cooling system generates a fog consisting of water droplets with a mean diameter of 10 to 30 μm, which cools the ambient air through the heat of vaporization of the fog. Typically, this system cools the air by two to four degrees C, with the potential to reduce the temperature by a maximum of 20 degrees C in extremely high-temperature and low-humidity regions, such as in Middle Eastern countries.

1. Why Gas Turbine Inlet Air Cooling in Summer?

A gas turbine operates by taking in ambient air, compressing it, injecting fuel into it, and igniting the mixture to power the turbine and generate electricity. During the summer, the rise in temperatures causes the ambient air to expand, resulting in a decrease in its density, which subsequently reduces the mass flow of air taken into the turbine.

Working mechanism of a gas turbine

*Working mechanism of a gas turbine

Additionally, as the mass flow of inlet air diminishes, the volume of fuel injected into the combustor decreases as well, in accordance with the gas turbine's design to maintain a consistent air-fuel ratio for optimal combustion. As a result, the power output of the gas turbine decreases. It is generally observed that the power output decreases by 0.6 to 0.8% for every one-degree Celsius increase in ambient temperature. The purpose of inlet air cooling is to increase the density and mass flow of the inlet air by lowering its temperature, and simultaneously increase the volume of injected fuel in order to recover the diminished power output. This approach allows a power plant to maintain a consistent electricity supply at affordable costs without having to invest in building new power generation facilities at huge expense.

A gas turbine inlet air cooling system

*A gas turbine inlet air cooling system

2. Advantages of Fogging Systems for Inlet Air Cooling

Multiple methods are available for cooling the gas turbine inlet air, such as media-type evaporative cooling, chiller-based cooling, and fogging. Among these options, the fogging system has gained traction due to its advantages, including its ease of installation on existing gas turbines and relatively affordable investment costs for returns, compared to the other methods. As a company that began its journey as a manufacturer of spray nozzles, IKEUCHI also provides a fogging system that utilizes our specialized nozzles to cool the inlet air of a gas turbine.

Fogging inlet air cooling systems

*Fogging inlet air cooling systems

3. Gas Turbine Inlet Air Cooling System | System Configuration

Spray nozzle manifolds

Spray nozzle manifolds

The use of high-precision spray nozzles enables the spraying of a fog formed with water droplets that are highly uniform and finely atomized.

Temperature & humidity sensors

Temperature & humidity sensors

Sensors to measure temperature and humidity and then transmit these signals. Installation positions vary depending on whether the system is used for upstream or downstream fogging.

Pump units

Pump units

Pump units to generate high-pressure water to be supplied to the spray manifolds.

Control panel

Control panel

A control panel that allows for the adjustment of the spray flow rate from the nozzles by detecting variations in climate conditions, such as temperature and humidity.

4. Gas Turbine Inlet Air Cooling System | Features and Advantages

  • The system sprays "Semi-Dry Fog®" formed out of very fine water droplets with a mean diameter of 10 to 30 μm, without including large droplets that can cause wetting. It utilizes the heat of vaporization to cool the inlet air.
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  • The system uses specialized spray nozzles elaborately designed for the inlet fogging.
  • The fogging system is available in three distinct types: "upstream fogging", which involves fogging outside the gas turbine filter house; "downstream fogging", which incorporates fogging within the inlet air duct; and "Wet Compression", a method that sprays atomized water into the compressor. IKEUCHI provides all of these options within its product offerings.
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  • Furthermore, we employ computational fluid dynamics (CFD) technology to create 3D models to simulate the flow of fluids and their interactions in a gas turbine at a customer's site. This enables us to design an optimized system.
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5. Gas Turbine Inlet Air Cooling System | Benefits

The system is capable of reducing the inlet air temperature by approximately two to four degrees Celsius in Japan. In regions with high-temperature and low-humidity climates, this reduction can be extended to as much as 15 to 20 degrees Celsius. It is generally noted that for every one-degree Celsius decrease in the inlet air temperature, the power output increases by roughly 0.6 to 0.8%. This implies that reducing the inlet air temperature by 20 degrees Celsius increases the power output by 12% or more.

  • During a demonstration conducted in a Middle East country, our fogging system consistently achieved a 15-degree Celsius reduction in the inlet air temperature.
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  • In the same demonstration, fogging boosted the power output of the gas turbine from an average of 77.3 MW to 85.4 MW, marking an approximate 10% increase.
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Other benefits:

  • Semi-Dry Fog®, composed of ultra-fine water droplets swiftly evaporates upon spraying, effectively cooling the inlet air.
  • Specialized spray nozzles ensure uniform and even cooling of the inlet air, whether at the duct opening for upstream fogging or within the duct for downstream fogging.
  • Without releasing excess water or causing wetting within the duct, the system efficiently cools the inlet air using a reduced amount of water.
  • The system is available at relatively affordable investment costs and requires lighter maintenance compared to other inlet air cooling options.
  • A system of the "upstream fogging" type can be additionally installed on an existing gas turbine even while it is in operation.

6. Actual Installation Examples

These are just a few examples of actual installations.

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7. Summary

Gas turbine inlet air cooling systems are employed to recover the decrease in power output caused by the rise in temperatures during the summer. Among the various cooling approaches, the fogging system stands out due to its advantages, such as a lighter investment, easier maintainability, and ease of installation on existing gas turbines. IKEUCHI also offers this fogging-based cooling system. The fogging system is available in three distinct types: "upstream fogging", "downstream fogging", and "Wet Compression". IKEUCHI provides all of these options within its product offerings. Moreover, we utilize computational fluid dynamics (CFD) technology to create 3D models that simulate the flow of fluids and their interactions, in order to design an optimized system. Our system, equipped with specialized spray nozzles of our own that produce a very fine and uniform Semi-Dry Fog®, achieves effective inlet air cooling. The system is capable of reducing the inlet air temperature by approximately two to four degrees Celsius, or 15 to 20 degrees in regions with high-temperature and low-humidity climates, thereby boosting the diminished power output.

How to order

Have a question? We don’ t provide cataloge items. We can provide custom-made products to meet your requirements.

Please inquire or order for a specific nozzle using our coding system.
The coding system is described in our catalog downloadable by clicking "Catalog" button placed below.
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