Ventilation Challenges for Gas Turbines in Warm Climates
While there is a risk in warm climate areas for a turbine package to experience freezing weather and have a need for the type of gas turbine ventilation solutions we discussed in our last blog on cold climates, in this article we are going to discuss how a combustion turbine ventilation system needs to be designed for warm climates.
Counteracting the heat generated
Much like cooling any other heat-generating piece of equipment, the ventilation design of a combustion turbine needs to start with the amount of heat being generated. From a ventilation standpoint we are primarily interested in the amount of heat that is radiating from the combustion turbine casing and uninsulated or poorly insulated exhaust ducts. Once the amount of heat is known, Eldridge uses a tried and proven method of calculating the amount of airflow required to dissipate the heat.
Since it is not practical to try to ventilate a turbine package to a level that equals ambient temperature, the industry accepted method is to provide ventilation for a package that will maintain an acceptable temperature level above ambient temperature. For instance in a facility where personnel are allowed to be around the operating equipment, 15-20°F above ambient temperature would be an acceptable level. However, in a combustion turbine application where personnel does not enter the space an acceptable temperature above ambient temperature might be closer to 60°F. Therefore, in these cases where personnel are not allowed in the enclosure while the turbine is running, the limiting factor is the instrumentation and electrical equipment that would be affected and/or damaged by higher temperatures. The same formulas apply to the ventilation calculations in both scenarios, but flow is metered to meet the higher or less stringent requirements.
If your materials can’t stand the heat
When designing these high temperature systems, we also have consider the materials used in the fan sets. Seals and other equipment on a 60°F above ambient system must be designed for the higher temperatures. For instance, on a 100°F day the temperature inside the enclosure would reach 160°F and cause some materials to soften and fail. In these cases a material such as Teflon or Viton must be used in place of lower temperature material.
Another aspect of ventilation design that must be considered especially in warm climate applications for turbine generators is redundancy. If a turbine generator is cooled by only one fan set and that fan set happens to fail, the turbine can no longer be operated without cooling. Therefore all turbine generator sets should have at least 100% redundancy on the ventilation system. So if one fan set fails, the other set can be started and the turbine can be in operation while the failing fan set is repaired. And for heaven’s sake, if one fan set fails, don’t wait around to repair the failed set. The fan set that is still running may fail as well since both fan sets are typically the same age.
Let us help you
We always recommend working with a ventilation expert for these applications. Having your system designed and installed by professionals will help you avoid downtime and wasted dollars. Our philosophy is to design a system that works with trustworthy equipment. Contact us today to discuss your gas turbine ventilation challenges.