The International Gas Union holds the World Gas Conference every three years, with the last event having happened in June 2018 in Washington, D.C. As the 2021 function in Daegu, South Korea nears, the issue of greenhouse gas emissions and energy efficiency is still the elephant in the room. Ask anyone in this massive industry; it is always a welcome relief to find a technology that promotes fuel efficiency. ARANER has been on the forefront, advocating for and promoting energy efficiency measures in industrial settings. Turbine Inlet Air Cooling and Thermal Energy Storage (TES) are popular technologies that are giving a lifeline to power plants in some regions. If you are yet to use this approach in your plant, what are you missing? Is it something that you can implement? What are some of the issues to ponder over before having TIAC/TES installed?
Thermal energy storage (TES)
There are several demand side management tools, but few are as effective as TES for power plants. Summer time in some regions can be overwhelming when the peak electricity demand increases. Sometimes, the power demand may prompt proprietors to think about expansion. With TES benefits, it is possible to avoid such expansions and reduce peak power demand. A TES system comprises of the following major components:
- Heat exchanger
- Mechanical chiller
- Ice maker-in ice storage setups
Fig.1. TES System
When talking about thermal energy storage systems and applications, emphasis is often placed on stratified chilled water storage (under the umbrella of chilled water storage categorization) because it is consider highly cost-effective, energy efficient and simple to implement. It is rare to find a solution that provides a win-win situation for both the utility company and the customer, yet TES does it blatantly. In its basic design, TES is about production of cooling energy during off-peak hours (usually at night) and delivering the same during on peak hours (usually during the day). You could liken it to a pumped hydropower station, which uses excess power during the night to pump water to a reservoir, the water running down the system during the day to create electricity.
Turbine Inlet Air Cooling (TIAC)
Then there is TIAC, an innovative technology for improving gas turbine performance, particularly during the hot seasons and in peak hours. This intervention is inspired by the fact that gas turbine performance is closely linked to ambient air temperature – the lower the temperature, the higher the air density, and the easier it is to transfer air mass in the turbine. ARANER does improve gas turbine performance using this technology, and the results can be proven from this case study. Studies on TIAC benefits have shown that the solution can help increase power plant efficiency by as much as 30% and augment power output by between 20 and 25%. Implementing TIAC in your power plant could see 10-15% in power cost savings. All this can happen without adding a single turbine- there’s no additional maintenance or capital costs. With that background, what would you say about the integration of TIAC and TES? It is possible!
TESTIAC- Reasons the Combination Makes Sense
That’s the name of this combination. It’s derived from the acronyms of both technologies. This combination is relevant when designing a TIAC system for peak demand. In this case, TES tank reduces capital investment and operational cost. Many experts will actually recommend a TES tank for any Turbine Inlet Cooling system that is based on inlet chilling technology i.e. one that features cooling coils, pumps and a chiller plant.
Figure 2. Overview of GT inlet cooling systems. Source: GPPS Journal
With the TES tank in place, the power plant owner or operator can minimize the parasitic electric loads significantly during the turbine inlet chilling operation. The result is optimization of the available grid power. TIAC/TES combination is also an excellent way of taking advantage of surplus from the electric grid in peak periods. This installation can be performed in afresh, as a rehabilitation, or even expansion of the facility.
Factors for Best Results
A seasoned consultant from ARANER in partnership with the tank manufacturer can ascertain the physical size and capacity of the TIAC/TES system. Briefly, the team puts crucial variables into consideration when combining TIAC with TES, including:
- System temperature for both return and supply line
- Required cooling load to be accommodated by the tank in terms of tons
- Duration in hours that the tank will cool the inlet air of the gas turbine
- Desired economics from the arrangement i.e. the team has to choose between partial shift TES and full shift TES
Turbine inlet air cooling systems are present in different geographical locations, but each installation has unique requirements. The best design results come when every plant is treated individually, especially when incorporating the reliable thermal energy storage technology. Chiller operating conditions, TES tank size, power plant output, and water consumption are some of the factors that will vary from one project to another. Optimize your power plant with TIAC/TES- work with ARANER’s time tested team.