Heating, Ventilating, and Air-Conditioning (HVAC) - PowerPoint PPT Presentation

1 / 33
About This Presentation

Heating, Ventilating, and Air-Conditioning (HVAC)


HVAC terminology: Btu Indoor Air Quality (IAQ) Duct loss Cubic Feet/ Min. (CFM) Heat transfer multiplier Indoor temperature Air Changes per Hour (ACH) ... – PowerPoint PPT presentation

Number of Views:450
Avg rating:3.0/5.0
Slides: 34
Provided by: Eng139


Transcript and Presenter's Notes

Title: Heating, Ventilating, and Air-Conditioning (HVAC)

Chapter 21
  • Heating, Ventilating, and Air-Conditioning (HVAC)

Code Requirements
Heating Systems
HVAC Drawings
Zone Control
3 Methods of Heat Transfer? Hint (C.C.R)
  • Heating, ventilating, and air-conditioning (HVAC)
  • Heating and air-conditioning equipment, and
    systems found in a building
  • Also referred to as the mechanical system
  • Regulates temperature
  • International Residential Code (IRC)
  • Requires a heating unit in any residence built in
    an area where winter design temperature is below

Thermal Calculations for Heating/Cooling
  • Necessary to establish the correct
  • Furnace
  • Ductwork
  • Supply
  • Return register specifications
  • Historical primary use
  • Calculate design heat load of houses to estimate
    gas and oil heating systems size

Thermal Calculations for Heating/Cooling (contd.)
  • HVAC terminology
  • Btu
  • Indoor Air Quality (IAQ)
  • Duct loss
  • Cubic Feet/ Min. (CFM)
  • Heat transfer multiplier
  • Indoor temperature
  • Air Changes per Hour (ACH)
  • Indoor wet bulb
  • Infiltration
  • Internal heat gain
  • Latent load
  • Mechanical ventilation

Thermal Calculations for Heating/Cooling (contd.)
  • HVAC terminology (contd.)
  • Outdoor temperature
  • Outdoor wet bulb
  • R-factor
  • Sensible load calculations
  • Temperature difference
  • U-factor

  • Automatic mechanism for controlling heating or
    cooling by a central or zonal system
  • Location is important

Exhaust Systems Code Requirements
  • Exhausts are part of the HVAC system
  • Exhaust systems are required to remove odors,
    steam, moisture, and pollutants
  • Refer to the text for basic general code

HVAC Code Requirements
  • National Energy Conservation Code regulates the
    design and construction of
  • Exterior envelope and selection of HVAC
  • Service water heating
  • Electrical distribution
  • Illuminating systems and required equipment
  • Refer to the text for general code requirements

Code Requirements
  • IECC is updated every three years and is designed
    to provide an energy efficient environment for
  • Equipment in a garage must be protected from
    automobile impact (slab on grade construction
    would have a 18 platform)
  • Programmable Thermostat
  • Exterior (Building) envelope is space that is
    heated and cooled
  • Conditioned (finished square footage)
  • Unconditioned (basement unfinished)
  • Must be separated by a door

Code Requirements
  • A door or access large enough to remove largest
    piece of equipment
  • Unobstructed working space not less than 30 wide
    and high should be provided next to the control
    side of the equipment (Furnace, WH)
  • An GFCI electrical outlet and lighting fixture
    should be provided near the equipment and have a
    switch at the doorway or access (In attic)
  • Equipment located on the ground should be
    supported on a concrete slab and be at least 3
    above the ground. (AC units)
  • Fuel burning warm-air furnaces must be supplied
    with combustion air
  • All exterior ducting (Avoid at all costs) should
    be weatherproof and insulated
  • In basements all supply lines should be insulated
    with R-4.2 insulation unless wall drapes are used
    to consider it conditioned space

Minimum Dimensions
  • Furnace 24 x 30
  • Water Heater 18-24 Diameter
  • Electrical Panel 30 open space
  • Pex Piping

Duct Systems
  • Cold Air Return
  • Supply

Central Forced-Air Systems
Forced Air Systems
  • A fan forces air into ducts that connect to air
    supply registers
  • Air is heated during the heating cycle and the
    combustion is vented out flue
  • Cooled air is passed over a cooling coil which is
    cooled with a refrigerant (Puron)

Forced-Air Heating Plans
  • Complete forced-air heating plans show
  • Size, location, and number of British thermal
    units (Btu) dispersed from warm-air supplies
  • Location and size of cold-air return
  • Location, type, and output of furnace
  • Providing duct space (i.e., chase)
  • When ducted heating and cooling systems are used,
    duct location becomes important

Central Air Systems
  • Rules to Design
  • Place Central Air Condenser unit at shortest
    straight line to exterior side or rear of home
    for coil (efficiency)
  • Place Ducting trunks cold air returns and supply
    lines to one side of bearing wall (Stairs)
  • Add Combustion Air Intake direct line same
    direction floor joist are running

Zone Control Systems
  • One heater and one thermostat per room
  • No duct work
  • Only heaters in occupied rooms need to be turned
  • Types
  • Baseboard
  • Fan heaters
  • Split systems

Alternate Method using Zone Controls
  • Individual rooms are heated and cooled as needed

Hot Water System
  • Water is circulated through a radiator after
    being heated in an oil- or gas-fired boiler
  • One-pipe system has heated water pass through
    radiators and returns in the same pipe to the
  • Radiant Flooring is growing in popularity

Hot Water Systems
  • Water is heated in an oil- or gas-fired boiler
  • Then circulated through pipes to radiators or

Radiant Heat
  • Radiant heating and cooling systems
  • Control surface temperatures
  • Minimize excessive air motion
  • Annual operating cost savings of 20 to 50
  • Lower thermostat settings
  • Superior, cost-effective design

Heat Pump/ Geothermal / Passive Solar Systems
  • Heat is extracted from outside air and pumped
    through a compressor into the structure
  • Heat pump systems are 30 to 50 percent more
    efficient then forced air systems
  • Air is cleaner and fresher with a heat pump system

Heat Pump Systems
  • Forced-air central heating and cooling system
  • Compressor and circulating refrigerant system

Exhaust System Code Requirements
  • Vented hoods must have back draft damper
  • Direct vent to exterior suggested for gas or
    exhaust fan in kitchen
  • If gas dryer or other fuel burning appliance (Fan
    is good idea)
  • Clothes dryer vents independent from all other
  • No screws in vent
  • Back draft damper
  • 4 duct no longer than 25
  • Total length reduced 2.5 for each 45 bend and 5
    for each 90 bend

Heat Recovery and Ventilation
  • Uses a counter flow heat exchanger between
    inbound and outbound airflow
  • Air pollutants
  • Principle reason for installation
  • Air-to-air heat exchangers
  • Pulls polluted, stale, warm air from the space
    and transfers heat in that air to fresh, cold air
    being pulled into the space

(No Transcript)
Gas lines
  • Meter
  • Pressurized Gas
  • 2lb
  • 4 oz

HVAC Drawings
  • Drawings for the HVAC system show
  • Size and location of all equipment, ductwork, and
  • Use accurate symbols, specifications, notes, and
  • Form the basis of contract requirements for

(No Transcript)
(No Transcript)
Residential HVAC Drawings
  • Show Thermostat location
  • Heat Register Locations
  • 4 x 10 floor or 2 x 10 under cabinet
  • Cold air return is needed for every 5 heat
  • 14 x 8 single or 30 x 8 double
  • Size of room and use determines number of
    registers needed 150 square feet Single

Residential HVAC Drawings
Show Supply and Return Main Trunk Lines Dryer
Vent Location Combustion Air Location
Write a Comment
User Comments (0)
About PowerShow.com