Turbine Inlet Coils, Part 1: The Importance of Inlet Heating

Part 1: The Importance of Inlet Heating

Turbine inlet heating coils are used in gas-fired power plants to heat the air entering the gas turbines. There are two main ways that a plant can benefit from adding heating coils to its turbines: the coils increase the efficiency of the plant when idling, and they prevent freezing. Both benefits are discussed in detail below.

Increasing output and efficiency

Marlo Heat Transfer Solutions turbine inlet heating coils are used to increase the temperature of the incoming air, which increases the efficiency of the turbine, especially when the turbine is not operating at full capacity.

As renewable energy sources such as wind and solar become more prevalent, gas turbines are increasingly used to supplement renewable power to meet ever-changing demand, and therefore run at various levels of capacity throughout the day. In regions with significant wind and solar usage, traditional gas-fired plants might only run at full capacity for a few hours in a 24-hour period.

This need to continually ramp up and ramp down power output creates serious efficiency challenges for the gas turbines. However, by pre-heating the air entering the turbine,  major increases in efficiency can be gained. And that’s exactly what our turbine inlet heating coils are designed to do.

In “turn down” situations, when less power generation is required, and the turbines are therefore operating at less than full capacity, heating the inlet air allows the turbines to produce the needed power while using less fuel than would be used if colder air was entering the turbine. So, the cost of power generation is reduced during these times of partial-load operation.

As the adoption of wind and solar power continues to grow, Marlo turbine inlet heating coils can help make this transition to renewable energy easier, and more cost-effective for power companies.

Eliminating repairs and downtime due to freezing

The other important role turbine inlet heating coils play in gas-fired power plants, particularly in regions where temperatures commonly fall below 40˚F, is to prevent icing.

Ice buildup on gas turbines can negatively affect turbine performance, and at worst, cause serious damage. In cooler climates, humid air can cause ice formations which can be carried into the gas turbine intake. When these ice crystals come in contact with the rapidly spinning turbine blades, significant damage can be caused to the blades, which results in extensive downtime and costly repairs.

Lastly, when air enters the filter house a lot of times is has a modest increase in velocity as it travels through the filters.  There are conditions where the cold moist air will sometimes collect and freeze on the filters.  Once this process starts, the airflow to the turbines can be seriously compromised.  As the filters freeze the air velocity continues to accelerate further compounding an already bad situation.  Heating the air prior to entering the filters eliminates that possibility of moisture freezing on the filters and creating a situation where the turbines must be taken offline and halting production

Of course, heating the air entering the turbine with an inlet coil will eliminate this serious risk in cold temperatures. The colder the climate, the higher the risk of freezing – and the more advantageous it is for the plant to add turbine inlet heating.

Unmatched expertise in turbine inlet coils

Marlo Heat Transfer Solutions has many years of experience providing heating coils for gas turbine inlet applications, across the United States and around the world, for turbines ranging in size from 20MW to over 500MW. 

Each turbine coil is custom engineered and manufactured to meet the needs of each individual application, with careful consideration to the climate in which it will be used. Our coils have performed effectively under very extreme conditions, continually demonstrating their performance, durability and reliability.

We have worked closely with many of the system suppliers and OEMs over the years, and our turbine inlet coils are approved by all major turbine manufacturers. We have proven time after time our ability to provide power plants with cost savings, increased efficiency, optimum turbine performance, and overall system protection.

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