HVAC Basics

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HVAC Basics

• The Basics of Heating, Ventilation and Air
  Conditioning
• Presented by Mark Kartchner, PE, LEED
• Kartchner Engineering

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Energy Use Office Buildings
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Mechanical System Costs

• First Cost - Water cooled chillers beat Air
  cooled chillers at about 200 Tons (80,000 SF)
• SEL HQ VAV-10.5/SF, FP-1.9/SF, Plumb-3.4/SF
  90,000 SF
• CWC 12.5/SF WSHP 3.5/SF Plumb 90,000 SF

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HVAC Rules of Thumb

• Air - 1 CFM/SF
• Cooling (office) 300/400 SF/Ton
• Cooling (office) 400 CFM/Ton
• Heating 25-35 btuh/sf floor area
• Outside Air 20 CFM/person
• Toilet/Jan Closet 10 air changes/hour

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HVAC Equipment/SF

• Mechanical Room (Boilers/Chillers/Pumps/Misc)
• GU College Hall 2000 SF/186,000 1.1
• Mechanical Room (Boilers/Pumps/Misc)
• RTF (tight) 300 SF/28,000 SF 1.1
• Colbert Elementary 312 SF/ 40,000 SF 0.8
• RTU (Gas/Electric/VAV)
• SEL Office (35x12 (2))/95,000 SF

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Building Envelope
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Load Calculations

• Heating and Cooling
• Accuracy important!
• Design conditions
• Building shell load
• R, U value
• Internal load
• Ventilation load
• Infiltration
• Occupancy schedules

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Heat Transfer

• Conduction
• Convection
• Radiation
• Resistance (R-Value)
• U 1 / R
• Q U x A x ?T

U-Value is the rate of heat flow in Btu/h through
a one ft2 area when one side is 1oF warmer
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Actual R-Values
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Window Types
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Solar Heat Gain Coefficient

• The amount of solar heat energy allowed to pass
  through a window
• Example SHGC 0.40
• Allows 40 through and turns 60 away

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Window Properties
Energy Calculations in the Spokane region show
that reflective, and tinted windows increase
energy usage on an annual basis.
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Energy Saving Design Methods

• ?? Air Side Economizers
• ?? Water Side Economizers
• ?? Variable Frequency Drives
• ?? Building Diversity
• ?? Part Load Performance
• ?? Thermal Storage
• ?? Heat/Energy Recovery

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HVAC SYSTEMS

• Heating, Ventilation and Air Conditioning
• Provides comfort for people
• Allows humans to exist under adverse conditions.

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Basic Refrigeration Cycle
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System Types

• Packaged Rooftop Unit
• Split System
• Air to Air Heat Pump
• Water Source Heat Pump
• Geothermal
• VAV Variable Air Volume
• Under Floor Air Distribution (UFAD)
• Air to Air
• Hydronic (water)
• PTAC / PTHP

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Packaged Rooftop Units (RTU)
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Split System
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Heat Pump (Air to Air)

• Operate on simple refrigeration cycle
• Reversing the cycle provides heating
• Temperature limitations
• Air to air
• Water source
• Geothermal
• Lake coupled

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Water Source Heat Pump
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Geothermal Heat Pump Systems
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(VAV) Variable Air Volume
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VAV Terminal Units

• Variable volume Parallel

Constant volume Series
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Under Floor Air Distribution (UFAD)

• Advantages
• Individual Controllability
• Re-Configurability
• 2 Extra LEED Points
• Disadvantages
• More Expensive (8/SF for raised floor)
• Flexible for Change
• 2 Extra LEED Points
• Inland Power Light
• First UFAD in area

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Hydronic systems

• Four Pipe Fan Coil
• VAV w/ HW Reheat

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Hydronic System Major Equipment

• Chillers
• Boilers
• Cooling Towers

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Chilled Water System
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Economizers
Air Side
Water Side
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Economizers

• Free cooling source When available, use cool
  outdoor air instead of mechanically cooled air.

Minimum supply of outside air
55 oF and up
55 oF
85 outside air
85 exhaust
80 oF
80 oF
Normal Operation Outside air dampers are
positioned to provide the minimum outside air
Economizer Operation Outside air dampers are
fully open. Maximum outside air is provided
HVAC-29
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Enthalpy Wheels
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Air Distribution

• Grilles, Registers
• Many options
• GU Russell Theatre Return Grille
• Return Plenum
• Extra cost for plenum rated cable is less than
  cost of return ductwork
• No Combustables

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Outside Air Louvers

• Outside Air Louvers provide an opening in a
  building wall to push air out, or pull air in.
• Provide clean outdoor air, avoid
• loading docks
• exhaust vents
• plumbing stacks
• waste collection
• stagnant water

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Metal Ducts

• Square Ductwork
• Most common
• Low height
• Round Ductwork
• Less Expensive
• Easy to Install
• Lower static pressure
• Taller than Rectangular
• Higher pressure
• Less Sound
• Oval Ductwork
• Same advantages of round
• Height similar to rectangular
• More expensive than rectangular

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Fabric Ducts

• Great for certain applications
• Gyms
• Pools
• Manufacturing
• Spokane Science Museum
• Advantages
• Great Diffusion
• Easily Cleaned
• Fun
• Same cost as metal

Saved 300,000 in cost at high school. Lowered
chilled water temp, air temperatures
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Additional Equipment

• Heat Exchangers
• Humidifiers
• Silencers

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Kitchen Hoods

• Type 1 Hoods designed for grease exhaust
  applications
• Type 2 Hoods designed for heat and steam removal
  and other non grease applications. (NFPA 96 does
  not cover)
• Where are Type 1 Commercial Hoods Required?
• NFPA 96 Cooking equipment used in processes
  producing smoke and grease-laden vapors shall be
  equipped with
• NPFA 96-A-1-1 intended to include residential
  cooking equipment where used for purposes other
  than residential family use
• Type 1 Hood Clearances
• 18 inches to combustible material
• 3 inches to limited-combustible material
• 0 inches to noncombustible material

A restaurant with a commercial gas range is
represented by the resteaurant owner to be used
ony for the preparation of soups. What type hood
is required? Type 1 hood is for collection and
removal of grease laden vapors,and smoke. Type II
hood is for removal of steam, odors, and vapors.
It would be hard pressed to find a restaurant
that only produces soups, with that commercial
range. Hoods where required, installed at or
above all commercial-type deep fat fryers,
broilers, fry grills, steam-jacketed kettles,
hot-top ranges, ovens, barbeques, rotisseries,
dishwashing machines, and similar equipment that
produces comparable amounts of steam, smoke,
grease, or heat in a food processing
establishment. Food processing establishment
shall include any building or portion used for
the processing of food. Soup is a liquid food
made up of simmering vegetables, seasonings, and
often meat or fish. It is the potential of the
equipment (Commercial gas range), rather than the
utilization, that must be evaluated. So, what
type of hood would be required for that
commercial gas range in a restaurant would
honestly be open for discussion. You will
probably have some input from your local Fire
Dept. through plan check as with the County
Health dept. Requirements. I know of one City
close to us that when a pizza parlor opens, no
matter what, they require a type 1 hood.
Depending on the type of pizza oven, we have
allowed a type II.
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Kitchen Hood Types

• Exhaust Hood w/ Supply Air Supplied by Space
• Exhaust Hood w/Supply Air on Outside of Hood
• Exhaust Hood w/Supply Air on Inside of Hood
• Vapor Hoods
• Simple hoods designed to remove minimal heat, and
  high vapor.

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Comfort

• Comfort is primary intent of HVAC systems.
• Productivity
• Building Durability
• Health
• Mold

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ASHRAE Comfort Zone
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Psychrometrics

• Dry bulb temp.
• Wet bulb temp.
• Humidity
• Dew point
• Moisture content
• Heating
• Cooling
• Humidify
• De-Humidify

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Historical Minimum Ventilation Rates (cfm/person)
Smoking 62-89
Flugge 1905
Billings 1895
Nightengale 1865
Smoking 62-81
ASH- RAE 62-89
ASHRAE 62-73
Tredgold 1836
Yaglou 1938
ASHRAE 62-81
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Improved Ventilation Effectiveness

• Mechanically provide filtered and dehumidified
  outdoor air to the breathing space
• Vary ventilation based on the number of occupants
  and process loads - changes in occupancy can be
  measured by CO2 sensors
• Consider designs that separate ventilation and
  space conditioning
• Utilize heat recovery systems to reduce system
  size and ventilation energy costs

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Improved Ventilation Effectiveness

• Effective mixing of ventilation air within space
• Net positive pressure in the southeast exhaust
  from appropriate spaces
• Provide clean outdoor air, avoid
• loading docks
• exhaust vents
• plumbing stacks
• waste collection
• stagnant water

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Acoustics
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Octave Band
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Directivity Factor
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LEED Products

• LEED-NC New Construction Major Renovations
• LEED-EB Existing Buildings
• LEED-CI Commercial Interiors
• LEED-CS Core Shell
• LEED-H Houses
• LEED-ND Neighborhood Developments
• LEED-Schools K-12 Schools
• LEED-Retail Retail facilities- In pilot stage
• LEED-Healthcare Healthcare facilities- In pilot
  stage

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LEED Checklist
http//www.metrokc.gov/dnrp/summit/documents/LEED-
Spataro.pdf
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http//www.metrokc.gov/dnrp/summit/documents/LEED-
Spataro.pdf
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THANK YOU!
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Additional Information / Resources

• ASHRAE The American Society of Heating,
  Refrigerating and Air-Conditioning Engineers
• www.ashrae.org
• Southface Energy Institute www.southface.org
• Geothermal heat pump consortium
  www.geoexchange.org
• www.buildingscience.com
• www.energycodes.gov
• HVAC Acoustics for Green Buildings Mike Filler.
  Ashrae technical committee for Sound and
  Vibration
• McQuay Application Guide AG 31-010 HVAC Acoustic
  Fundamentals
• Energy Efficiency in Buildings Dr. Sam C M Hui
  Department of Mechanical Engineering