Marion County Health Clinic – Salem, Oregon


Mechanical System Design / Deep Energy Retrofit


Marion County Health Clinic is a 50,000 sq.ft. architecturally unique county health clinic.  Originally designed and constructed in 1974, the building’s envelope, lighting, and mechanical system performance had deteriorated significantly.  In 2015,  Mike Hatten of SOLARC undertook an assessment of the mechanical system deficiencies that ultimately led to the design and construction of a major system renovation, as part of an overall building renewal project.Components that were completely modernized and upgraded included air distribution, heating, pumping, and controls.   Hatten designed the upgrade in which the mechanical system was downsized to respond to complete replacement of original single pane glass with modern high performance double paned glazing, and the upgrade of interior lighting to LED.  Hatten also led a parallel  energy analysis effort that identified overall energy savings potential and qualified the project for a sizable financial incentive from the Energy Trust of Oregon.


Project Summary


Overall, the building’s comfort has markedly improved in both heating and cooling seasons.  Building envelope no longer experiences excessive air infiltration.  Air distribution is significantly improved in all spaces.  Building maintenance and operations are also much easier due to replacement of failed components and use of the new graphics interface on the HVAC controls.  Key project performance parameters are listed below.


  • Building size:  50,000 sq.ft.
  • Annual electric energy savings: 743,000 kWh
  • Annual natural gas savings:  41,800 therms
  • Annual energy cost savings: $92,700
  • Percentage electrical use reduction: 70%
  • Utility incentive: $248,000
  • Mechanical system cost: $960,000


System Upgrade Elements


  • Replace existing pneumatic controls with new direct digital control system
  • Replace existing chilled water pumps
  • Abandon underground return air ducts
  • Replace all existing terminal units with new VAV terminal units with electric reheat
  • Remove existing gas-fired boiler and failing hydronic heating system
  • Replace existing fan motor with new premium efficiency motor and associated variable frequency drive (VFD)
  • Replace building relief fan with new fan system and associated VFD, properly sized and matched with renovated supply fan system
  • Install new low pressure ductwork and new supply air and return air inlets and outlets
  • Install new low leakage outside air dampers
  • Remove existing zone dampers inside of air handling unit and make modifications to open up the existing chilled water coil to full air flow.