Ventilation Issues: Package Rooftop Equipment

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Ventilation Issues Package Rooftop Equipment
Jeffrey A. Johnson, Senior Program Director New
Buildings Institute
A not-for-profit public benefits
corporation Promoting energy efficiency through
building energy codes, standards and guidelines
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CASE Initiatives

• Codes and Standards Enhancements (CASE)
• Project Goals
• Evaluate potential for technology or practice to
  deliver real energy savings through codes and
  standards
• Implement market transformation strategy that
  moves utility promoted technologies and practices
  into minimum practice
• Provide a platform for future market-based
  utility programs
• 2005 California Code Update

Project Sponsor
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CASE Initiatives

• LED Exit Signs
• Dry-type Transformers
• High-albedo (Cool) Roofs
• Package Rooftop Controls
• Lighting Controls
• HVAC Distribution Systems
• Time Dependent Valuation

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Package Rooftop Equipment

• Rooftop units over 65,000 Btu/hr require
  economizer
• Thermostat should keep fan running 55 min/hr
• Deliver .15 cfm/sqft outdoor air (varies)
• What is really happening?

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Market Share

• Two-thirds of cooling capacity in PGE Territory
  is package single zone equipment with 90 of
  building stock less than 10,000 sq.ft.
• 10 of installed capacity didnt meet Title 24
  economizer requirements and 10 not requiring an
  economizer had one installed

Source RLW Analytics
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Preliminary Findings

• Package Rooftop Units
• Economizer Failure modes
• Stuck OA dampers
• Sensor failure
• Controller failure
• 250 units monitored
• Very few had functioning economizers
• Fan Control
• Up to 50 in auto mode
• Oversized by 50 or more
• Outside Air
• Five tons and under typically dont have OA intake

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Impacts

• Service
• 400 vacant HVAC tech positions in San Jose
• Air Quality
• Low to no ventilation air
• Temperature and humidity problems
• Energy
• 1,000 GWH/yr PGE Territory
• 100 million/yr

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Next Steps
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Other Projects

• Public Interest Energy Research Project
• CA Nonresidential Quality Assurance
• Advanced Lighting Guidelines
• NEEA Better Bricks Guidelines
• Thermal Comfort
• Lighting
• Daylighting
• NEEP Regional Energy Code Project
• IECC and ASHRAE
• More information _at_ www.newbuildings.org