Keys for Heat Rate Improvement in Turbine Inlet Air Cooling

It is fascinating to see the level of transformation that turbine inlet air cooling technology (TIAC) has brought to power generation. TIAC is a welcome relief for power producers that are seeking to improve plant efficiency for less operating and maintenance costs, and higher efficiencies.

Turbine efficiency solutions are still advancing, but there are still things plant owners can do to achieve higher heat rate and efficiency. Reducing pressure losses and further optimization of components have been identified as possible areas of improvement.

It is a well-known fact that ambient conditions affect gas turbine performance. This can affect the efficiency of a power plant, hence the emergence of TIAC and other power augmentation solutions.

What TIAC does is eliminate the weather aspect; hence, it is popular in hot environments like Middle East and Tropical areas. You will find ARANER footprints all over the Middle East and other regions that are experiencing such ambient conditions.

We have learnt that heat rate improvement can increase annual savings as shown in these graphs.

Economic Benefits of Heat Rate Improvement in a Power Plant

Fig 1: Economic Benefits of Heat Rate Improvement in a Power Plant (Source)

So with Turbine Inlet Air Cooling the heat rate of the Gas Turbine is improved. However, it is also very important to maintain a high efficiency on the TIAC system so the global efficiency is increased.

The key point for the efficiency is the design of the cooling plant of the TIAC system. Refrigeration equipment and specially the chillers must be industrial grade, specifically designed for TIAC purposes with high efficiency.

But after putting into operation the TIAC system, a proper operation and maintenance are needed in order to maintain the efficiency levels as per the design.

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Maintenance and Checks for High Efficiency Achievement

Most people like to look after their most prized possessions. In most facilities, maintenance is one of the cheaper endeavors-not at all comparable to new installations or modifications.

Similar to the car engine, the chiller package is the heart of the TIAC system. It is therefore no surprise that most of ARANER’s focus is on this component. Of course, we also concentrate on other components because the health of the overall system is equally important.

To provide you with an overview of what it makes to maintain a good TIAC system for improved heat rate, here are some things to do often.

  1. Check compressor oil level
  2. Confirm operational condition of oil heaters. Most chillers will only operate if the oil is preheated
  3. Check cooling tower and take action if condenser cooling temperature is not as per design.

Once the system is up and running, you need to check the following things:

  1. Chilled water return line- it should be in full flow
  2. Temperature draw-down- system should operate within the design point
  3. Proper operation of control valve(s)
  4. Fully functional system temperature sensor
  5. Correct operation of heat rejection system in the chiller. Since most machine rooms operate optimally at around 80° F, it is important to check if the temperature is more than this standard. You might want to add ventilation to take care of this problem.

Quality of Water

Whether you are dealing with a closed loop, closed loop or chilled water system, you need to maintain good water chemistry. Sludge and scale will eventually buildup if you rely on poor quality water. This can only lead to poor heat rate and lowered system efficiency. Water treatment can help increase heat rate in Turbine Inlet Air Cooling. Call ARANER to see how this can happen.

ARANER TIAC Expertise

ARANER offers mechanical chilling based on proven technologies-heat exchanger and chiller- to deliver the required cooling capacity. This offers optimal performance to the gas turbine. With many years of experience, we are usually able to identify instances of reduced heat rate even before the problem occurs.

With growing interest in this technology across the globe, we receive an increasing number of enquiries regarding heat rate improvement in Turbine Inlet Air Cooling systems. An almost common characteristic with these facilities is that they did not put a holistic consideration from the design and installation stages.

The ‘cooling set point’ is always a crucial parameter when setting up a turbine inlet air cooling system. You also need to consider the worst-case scenario in as far as ambient conditions are concerned. A lot of analysis goes into making the final determination of the compressor inlet air temperature. Of course, 15 °C is the standard cooling set point, the coincident dry bulb temperature at ISO conditions. However, this may not be the optimal set point in some instances.

ARANER knows that design flaws related to heat rate may occur in a TIAC system, especially in highly humid environments. Considering the fact that the design for cooling coils in filter house and chiller system may come from different vendors, the need for a holistic approach is evident.

Every project we oversee takes care of such loopholes for excellent heat rate performance. Such contributions led to accolades for DEWA’s environmentally friendly power plants. ARANER implemented TESTIAC at DEWA L1 Power Station. Contact us today so we can check if there was any disparity in the design of these components, followed by a re-design if necessary.

Conclusion

When installed and maintained correctly, Turbine Inlet Air Cooling can increase the performance of a gas turbine immensely. Because some installations may lack this foresight, instances of poor heat rate occur. Instead of living with an inefficient system that could derail company profitability, it is important for managers and owners to pursue keys for heat rate improvement as outlined here.

As a strict adherer to best practices in the industry, ARANER promises reliable performance of your TIAC system. These best practices cover a wide range of areas from individual components to overall system design.
 

 

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