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1. Mechanical Systems pae consulting engineers, inc. Nick Collins, P.E., LEED™ AP nickc@pae-engineers.com inspire interpret integrate

2. ? Mechanical Systems What kind of mechanical system?

3. Mechanical Systems Install the smallest, most efficient system possible: • Reduce perimeter loads through careful skin design. • Reduce internal loads: laptops, energy star equipment. Multnomah County Hillsdale Library Architect: Thomas Hacker and Associates

4. What Factors Determine the Mechanical System Selected? • Building Type • Office • Housing • Education, Higher Ed or Secondary • Industrial • Maintenance • Comfort Mark O. Hatfield US Courthouse Architect: BOORA Architects Sokol Blosser Wine Barrel Storage Facility Architect: SERA Architects

5. Comfort ASHRAE summer and winter comfort zones.

6. Mechanical Systems Passive vs. Active PAE Offices

7. COOLING • Direct Expansion • Packaged Rooftop • Chilled Water • Air Cooled • Water Cooled Central • Ground Water • Direct and Indirect • Evaporative Cooling • Distributed Heat Pumps Active Systems • Cooling • Heating • Air Distribution • HEATING • Hydronic • Conventional Hot Water Boilers • High Efficiency Hot Water Boilers (Gas) • Electric Heat • Gas Fired • Ground Coupled Heat Pump • AIR HANDLING • Central • Rooftop • Penthouse or Inside • Distributed Air Handling • Fan Coils • Unit Ventilators • Heat Pumps

8. Active Cooling Systems • Cooling • Direct expansion • Chilled water • - Air cooled • - Water cooled • - Ground Water • Direct and indirect • evaporative cooling • Distributed heat pumps

9. Cooling Systems Chilled Water Package Rooftop First Cost: Lowest potential first cost. Energy Cost: Higher energy cost. Maintenance: High maintenance costs - expected life of 15 years. Comfort: Reasonable – potential acoustical issues. University of Oregon School of Music & Dance Architect: BOORA Architects

10. Cooling Systems Chilled Water Air Cooled First Cost: In conjunction with air handlers. Energy Cost: Better than rooftop option. Maintenance: Lowest maintenance cost option - average life of 17 years. Comfort: High level of comfort.

11. Cooling Systems Water Cooled First Cost: Greatest first cost. Energy Cost: Lowest Energy cost. Maintenance: Equipment is highly reliable - chiller life is 27 years. Comfort: Provides the best in comfort - quiet operation.

12. Ground Source Heat Pumps GS heat pumps extract geothermal energy to condition buildings. Very low energy consumption. • Winter – moves heat from the earth to the building • Summer – moves heat from the building to the earth • Automatic controls are used to reverse the direction of the heat transfer

13. Ground Water • PSU Northwest Center for Engineering, Science and Technology. • Ground water well system with extraction and insertion wells. • No Boiler or Cooling Tower • Ground water is used for heating and cooling.

14. Heating Systems • Active Systems – Heating • Hydronic • - Hot water boiler • - High efficiency boiler - condensing • Electric heat • Gas fired

15. Heating Systems Hydronic Heating Systems Energy Cost: Mid range, between electric heat and high efficiency hot water. Maintenance: Requires little maintenance. Comfort: Excellent comfort.

16. Radiant Floor Heating • Consistent heating • Low energy usage • Slow response time

17. Heating Systems Electric Heat First Cost: Low first cost. Energy Cost: Very high. This will represent a 100% to 150% increase in energy cost due to rate differences between gas and electric. Maintenance: Low maintenance. Comfort:Step control on electric heaters. Acceptable comfort.

18. Active Systems – Air Handling • Air Handling • Central • Distributed • - Fan Coils • - Unit Vents • - Heat Pumps

19. Air Handling Package Air Handler • Variable Air Volume Air Handler • Distribution: • Conventional overhead • Underfloor • Lower energy savings - longer economizer cycle • Smaller cooling zone

20. Air Handling Systems Heat Recovery Energy cost: Low energy cost. Maintenance: Same as air handler. Comfort: Less than air handler, if provided without coils.

21. Natural Ventilation Passive Cooling PAE Offices

22. Advantages of Natural Ventilation • Simple • Lower first cost (15% less) • Lower operating cost (40% less) • User satisfaction through greater control • Elimination of mechanical refrigeration • Less environment impact • No mechanical noise

23. Disadvantages of Natural Ventilation • Temperature & humidity cannot be tightly controlled • No filtration • Reduced security • First cost higher if back-up A/C system is also required • Exterior noise can be a problem • Less flexible air intake locations – air quality issues • Large openings required with mass inspire interpret integrate

24. Strategies Single-sided opening ventilation Cross ventilation Stack-induced flows through double opening

25. Washington School for the Deaf Classroom Natural Ventilation • Daylighting • Thermal Mass • Night Flush • No Filtration

26. Thermal Mass / Night Ventilation • Need approximately 2 to 3 times the floor area • Can reduce maximum daytime temperature

27. Sustainable Design Mechanical Systems • What system? That depends . . . • Reduce loads to lowest possible amount • Know your client, maintenance, comfort, operating schedule, etc. • Select most efficient system possible • System Types • - Active • - Passive • - Mixed Mode

28. Shattuck Hall – Case StudyExisting Mechanical Systems • Two dedicated outside air units with steam heat, evaporative air cleaners • Multiple air zones with mix dampers • Gravity relief from each zone (open relief duct on roof) • Other smaller mechanical • systems. inspire interpret integrate pae consulting engineers, inc.

29. Existing Classroom inspire interpret integrate

30. Old Zone Dampers - Mixing inspire interpret integrate

31. Mechanical Systems Options • HVAC Option C – Conventional VAV • Hot water heating • Variable volume AHU’s • Medium pressure supply ductwork • VAV air terminal units in each space • Low pressure return ductwork • Return air plenums • HVAC Option D – Dedicated OA/Radiant • Hot water heating radiant panels • Fan-induced ventilation • Operable windows – manual • New AHU’s/Existing ductwork - for minimum outside air • Radiant Cooling – radiant cooling panels or chilled beams • HVAC Option A – “Natural” Ventilation • Hot water heating radiators • Operable windows – automatic, with trickle vents • Building Mass/Night Flush Cooling • HVAC Option B – “Natural” Ventilation/Mixed Mode • Hot water heating radiators • Fan-induced ventilation • Operable windows automatic • New AHU’s/Existing Ductwork • Cooling coils in new AHU’s deliver cold air through existing ductwork on extremely hot days inspire interpret integrate pae consulting engineers, inc.

32. Shattuck Hall New Mechanical Systems • Two dedicated outside air units with hot water heating, campus chilled water and filters • Temperature zones with VAV terminal units • Radiant heating and cooling panels • Gravity relief from each zone (open relief duct on roof) • Other smaller mechanical • systems. inspire interpret integrate pae consulting engineers, inc.

33. Energy Use in Shattuck Hall Estimated Energy Usage No envelope upgrades inspire interpret integrate

34. Radiant Panel Concerns • Guinea Pig or Innovative • Comfort • Noise • Condensate • Valve locations • Hot water leaks • Flexibility inspire interpret integrate

35. Radiant Panels and Valves inspire interpret integrate

36. Heat inspire interpret integrate

37. Radiant Ceiling Heating / Cooling • Dedicated outside air for dehumidification • Low mass means faster response time • Uniform heating and cooling • Low energy usage inspire interpret integrate