Puget Sound Energy Encogen Study

Coffman was commissioned to provide a detailed study for recommendations to freeze protect the existing Encogen Cogeneration Plant. The report included mechanical, electrical, structural, and civil engineering implications for each of the freeze protection options. The piping systems were reviewed to identify dead-end pipes and instrumentation susceptible to freezing and design recommendations were made to mitigate. The introduction of heat into HRSGs for freeze protection was also reviewed, including options to integrate electric boilers connected to hydronic piping systems as well as the addition of energy recovery dehumidification air handlers ducted to the HRSGs to maintain above freezing temperatures inside the HRSGs while isolating the HRSGs from outside air when the systems were not in operation utilizing stack and inlet balloons.


  • Energy & Utility


  • Civil Engineering
  • Electrical Engineering
  • Mechanical Engineering
  • Structural Engineering
  • Design-Build