COMMISSION AGENDA – Action Item Page 2 of 4
Meeting Date:
Template revised September 22, 2016; format updates October 19, 2016.
The new HVAC system, currently under construction, was designed with a variable hot water
recirculating system to provide greater energy efficiency for the Port. The variable hot water
recirculating system is a critical component required to meet Washington State Energy Code.
While performing initial testing and balancing of the new HVAC system, it was discovered that
the operating pressure of the existing hot water circulating system was less than 2 psi compared
to the required operating pressure of 50 to 60 psi. Upon investigation, it was determined the
existing 50-year-old constant volume hot water circulating pumps and piping configuration is not
compatible with the variable volume flow requirements of the new system and will not provide
the required operating pressure to allow the HVAC system to operate as needed. Unfortunately,
the implications of providing water to a variable volume system from a constant volume system
were overlooked during design.
The additional HVAC capacity will also accommodate the expansion of the Airport Dining and
Retail (ADR) at the SSAT, providing needed customer amenities. Maintaining comfortable heating
and cooling is a necessity for a satisfying customer experience. While the Port is interested in
undertaking a major renovation of the SSAT within the next 10 to 15 years, the project currently
underway is addressing the inadequacy of the old HVAC system and its risk of failure. Currently
the SSAT Concourse level is supported by a temporary HVAC system; the old HVAC system has
been demolished; and the new permanent HVAC system is being installed.
In addition to providing a more reliant HVAC system, upon completion it is anticipated the Port
will realize an increased heating and cooling energy efficiency of 15% to 20% on the SSAT
concourse level system. Calculations estimate electric savings of 163,300 kwh/year and natural
gas savings of 20,600 therms per year for a total energy savings of 21,168 therms/year and
reduced greenhouse gas emissions of 110 metric tons/year. (Approximately $20,000/year in
energy savings)
When design on this project began in 2015 the Port undertook a very detailed review of the scope
of work to be performed in the SSAT. This review focused on maintaining a minimal scope of
repairs and improvements to the SSAT to maintain building operations for a 10 to15 year period
while the Port planned for a major renovation of the SSAT. An outcome of the scope review was
a determination that the existing constant volume (CV) hot water circulating system could be
operated and maintained for the next 10 to 15 years.
The project’s design team has developed a design solution which will be implemented with this
change order.
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FINANCIAL IMPLICATIONS
There is no additional funding being requested in this memo.