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HVAC 101 The Basics of Heating, Ventilation and Air Conditioning Presented by: Mike Barcik and Jeff Ross-Bain, PE Southface Energy Institute.

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Presentation on theme: "HVAC 101 The Basics of Heating, Ventilation and Air Conditioning Presented by: Mike Barcik and Jeff Ross-Bain, PE Southface Energy Institute."— Presentation transcript:

1 HVAC 101 The Basics of Heating, Ventilation and Air Conditioning Presented by: Mike Barcik and Jeff Ross-Bain, PE Southface Energy Institute

2 Southface Energy Institute Sensible Solutions for Environmental Living Energy Code Workshops Greenprints Commercial Systems EarthCraft House www.southface.org

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

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

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

6 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 ft 2 area when one side is 1 o F warmer

7  The amount of solar heat energy allowed to pass through a window  Example: SHGC = 0.40 Allows 40% through and turns 60% away Solar Heat Gain Coefficient

8 Psychrometrics Dry bulb temp. Wet bulb temp. Humidity Dew point Moisture content Heating Cooling Humidify De-Humidify Psychrometric Chart

9 Basic Refrigeration Cycle Expansion Valve Compressor Evaporator Condenser

10 Basic HVAC Equipment Fans / Blowers Furnace / Heating unit Filters Compressor Condensing units Evaporator (cooling coil) Control System Air Distribution System

11

12 System Types and Common Terms Packaged Rooftop Unit Split System Heat Pump Geothermal Air to Air Hydronic (water) PTAC / PTHP Constant Volume Variable Volume Indoor Air Quality Direct Expansion

13 Packaged Rooftop Units

14 FURNACE A/C UNIT Ductwork Heating and Cooling Equipment Temperature & Humidity Controls Split System

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

16 Geothermal Heat Pump Systems

17 Variable Air Volume T T Variable Speed Return Fan Return Air Return Ducts Zone Thermostat Reheat Coil VAV Box Supply Ducts Variable Speed Supply Fan Filters Cool Coil w/Temp Reset Heat Coil w/Temp Reset HVAC-17

18 Terminal Units Variable volume: Parallel Constant volume: Series

19 Hydronic systems Pumps Piping Valves

20 Control Devices Thermostats Manual Programmable Optimum Start DDC Systems Variable Speed Drives Automatic Valves and Dampers Outdoor Sensors

21 Major Equipment Chillers Boilers Cooling Towers

22 Economizers Air Side Water Side

23 Economizers Free cooling source: When available, use cool outdoor air instead of mechanically cooled air. 55 o F 80 o F Minimum supply of outside air 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 80 o F 55 o F and up 85% outside air 85% exhaust HVAC-23

24 Zoning and Economizers Economizers provide “free cooling” when outdoor conditions are optimal Proper orientation & zoning yields comfort & efficiency N S WECore HVAC-24

25 Air Distribution Ductwork Metal Flexible Ductboard Grilles, Louvers, & Registers Dampers Shut off Fire Smoke Sealants Supports

26 Return Plenum Problems HVAC-26

27 Additional Equipment Energy Recovery Units Desiccant Systems

28 Additional Equipment Heat Exchangers Humidifiers Silencers

29 Mechanical Dehumidification Return air is mixed with ventilation air Cold coil condenses moisture Heat is added back (electric or gas) so that room air is not over cooled- Reheat Filter

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

31 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 CO 2 sensors Consider designs that separate ventilation and space conditioning Utilize heat recovery systems to reduce system size and ventilation energy costs

32 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

33 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


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