HVAC Energy Efficiency using Mass Flow and Building Pressurization

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HVAC Energy Efficiency using Mass Flow and
Building Pressurization

• Jay Richardson
• Professional Supply, Inc.

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Professional Supply, Inc. - PSI

• Professional Supply, Inc. was founded by Tom
  Kiser in 1979 to support Architects and Engineers
  in developing energy efficient HVAC designs
• PSI Technology has provided significant energy
  savings for Ford, Goodyear and Delphi
• Today, PSIs innovative energy solutions extend
  to waste heat recovery, lighting, photovoltaic
  and thermal solar based on precise energy models
• PSI has a strategic alliance with Giffels, Inc.
  to create Sustainable Energy and Building Designs
• PSIs Energy Service Agreement with Ford is a
  business model that delivers technical solutions
  to energy challenges with no capital expenditure
  by our clients based on guaranteed performance

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Todays Energy Challenge

• HVAC energy consumed for Commercial Buildings is
  4.5 quadrillion BTUs
• 13 for Heating
• 11 for Cooling
• 6 for Ventilation
• 6 Hot Water
• Americas Commercial HVAC creates 34 of CO2
  emissions 90.2 MMTCE
• HVAC Technology dates back 2000 years to the
  Roman Baths
• Incremental technical improvements will not solve
  the Global Climate Change Challenge

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Laws of Physics

• Cold air is heavier than hot air
• Hot air rises, cold air falls
• Air is subject to the laws of mass flow and fluid
  dynamics
• In Winter, warm air rises as a result of stack
  effect promoting cold air infiltration at base of
  the building
• In Summer, stack effect is less and hot air
  collects at the roof promoting heat retention in
  the building

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HVAC Engineering Practice

• HVAC Forced Air Handling Systems use a blower to
  push hot air
• HVAC designs require dampers or sized ducts to
  maintain pressure and velocity at the discharge
  vent
• Higher air temperatures are needed for personal
  comfort when air blows directly on people
• Temperature controlled by discharge temperature
  and thermostat
• Blow enough tempered air with volume, pressure
  and velocity to accommodate all possible
  conditions
• Buildings tend to draws air from outside to
  produce sufficient updraft and pressure
  differential for roof exhaust to be effective

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Traditional Design
50,000 scfm Air Supply
Powered Roof Exhaust
Ducted Supply
Negative Pressure Updraft
Discharge Vent
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Cool Air Heating

• Cool air is heavier than warm air
• Cool air introduced at the top of the building
  naturally falls to the floor
• This eliminates the need for ductwork
• This allows PSI to recover process and building
  heat gain to reduce energy needs
• Inverse stratification uses mass flow to provide
  energy efficiency while creating a comfortable
  workspace

55F
65F
72F
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Bigfoot Air Handler

• Capable of delivering 200,000 scfm of air with
  two 100,000 scfm centrifugal blowers
• Variable frequency drives give Big Foot the
  ability to adjust to the building air supply
  requirements, thus minimizing the electric and
  natural gas usages
• Fresh air and return air
  bypass dampers react
  automatically to system
  changes to
  maintain the
  building conditions
• Discharge head louvers
  direct air horizontally
  and vertically

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PSI Engineering Practice

• Big Foot distributes air at the truss and
  pressurizes the building.
• Pressurization and perimeter relief dampers
  allows PSI to control air distribution Without
  Ductwork
• Big Foot modulates air flow using VFD blowers and
  damper control
• Big Foot System maintains uniform building
  temperature and positive pressure

55F
65F
72F
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Global Controls

• Global controls continuously monitor and respond
  to interior/exterior temperature, humidity and
  pressure as well as wind speed/direction
• Big Foot modulates VFDs to adjust to building
  pressure
• In Winter, smart discharge heads respond to cold
  
  spots by directing warm air down to the floor
• In Summer, ventilation is
  increased at night to cool
  the
  building. During the
  day, outside air is
  
  minimized until the
  interior temperature
  
  exceeds the exterior,
  then
  ventilation is
  increased

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PSI Design Cool Air Heating
Bigfoot Air Supply
Global Controls
Diffuser at Truss Level
Exhaust Louvers
Monitors
Positive Pressure
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Average Ford Assembly PlantPSI Energy Service
Agreement

• Average of 8 Assembly Plants
• Plant 3.1 million sq. ft.
• Converted both Steam or Forced Air Gas Systems
• Abandoned 182 HVAC Air Houses and numerous Unit
  Heaters
• Installed 12 Big Foot Units and/or modified
  existing air handlers and 2 Direct Contact Hot
  Water Heater
• PSI Investment - 11 million
• Ford Guaranteed Energy Savings 2.0 million per
  year at 2000 Energy Prices
• Energy reduction from baseline year
• 54 Gas
• 46 Electricity
• ESA includes daily monitoring, new equipment
  warranty and monthly on site review.

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Energy Performance

• Building pressurization, global controls and Big
  Foot Air Handlers reduce first cost, operating
  cost and provide a better cleaner work
  environment
• The PSI approach using mass flow and building
  pressurization allows us to heat and cool
  uniformly with less energy
• Adaptive controls respond to internal and
  external temperature, pressure and humidity
• Complete energy model allows the client to
  prioritize their potential solutions

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