HVAC BasicsThe Basics of Heating, Ventilation and Air Conditioning

Presented by: Mark Kartchner, PE, LEEDKartchner Engineering

Energy Use Office Buildings

Mechanical System CostsFirst 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 SFCWC $12.5/SF WSHP & $3.5/SF Plumb 90,000 SF

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Mechanical System Costs (Provide & Install)

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RTU-Gas/Air Cooled8

RTU-Heat Pumps10.5

VAV-Elec Heat12

Multi Zone RTU14

VAV-Hot Wtr Heat14.5

WSHP-HP, Boiler, Chiller, Cooling Tower14.5

DOAS w/ 4-Pipe Fan Coil19

Variable Refrigerant Volume20

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Mech Sys. Costs

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Mechanical System Costs (Provide & Install)

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HVAC Rules of ThumbAir - 1 CFM/SFCooling (office) 300/400 SF/TonCooling (office) 400 CFM/TonHeating 25-35 btuh/sf floor areaOutside Air 20 CFM/personToilet/Jan Closet 10 air changes/hour

HVAC Equipment/SFMechanical 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

Building Envelope

Load CalculationsHeating and CoolingAccuracy important!Design conditionsBuilding shell loadR, U valueInternal loadVentilation loadInfiltrationOccupancy schedules

Heat TransferConductionConvectionRadiationResistance (R-Value)U = 1 / RQ = 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

Actual R-Values

Window Types

The amount of solar heat energy allowed to pass through a windowExample: SHGC = 0.40Allows 40% through and turns 60% awaySolar Heat Gain Coefficient

Window PropertiesEnergy Calculations in the Spokane region show that reflective, and tinted windows increase energy usage on an annual basis.

Energy Saving Design Methods

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

HVAC SYSTEMSHeating, Ventilation and Air ConditioningProvides comfort for peopleAllows humans to exist under adverse conditions.

Basic Refrigeration Cycle

System Types Packaged Rooftop UnitSplit SystemAir to Air Heat PumpWater Source Heat PumpGeothermalVAV Variable Air VolumeUnder Floor Air Distribution (UFAD)Air to AirHydronic (water)PTAC / PTHP

Packaged Rooftop Units (RTU)

Split System

Heat Pump (Air to Air)Operate on simple refrigeration cycleReversing the cycle provides heatingTemperature limitationsAir to airWater sourceGeothermalLake coupled

Water Source Heat Pump

Geothermal Heat Pump Systems

(VAV) Variable Air Volume

VAV Terminal UnitsVariable volume: ParallelConstant volume: Series

Under Floor Air Distribution (UFAD)AdvantagesIndividual ControllabilityRe-Configurability2 Extra LEED PointsDisadvantagesMore Expensive ($8/SF for raised floor)Flexible for Change2 Extra LEED PointsInland Power & LightFirst UFAD in area

Hydronic systemsFour Pipe Fan CoilVAV w/ HW Reheat

Hydronic System Major EquipmentChillersBoilersCooling Towers

Chilled Water System

EconomizersAir SideWater Side

EconomizersFree cooling source: When available, use cool outdoor air instead of mechanically cooled air.55 oF80 oFMinimum supply of outside airNormal OperationOutside air dampers are positioned to provide the minimum outside airEconomizer OperationOutside air dampers are fully open. Maximum outside air is provided80 oF55 oF and up85%outside air85%exhaustHVAC-*

Enthalpy Wheels

Air DistributionGrilles, RegistersMany optionsGU Russell Theatre Return GrilleReturn PlenumExtra cost for plenum rated cable is less than cost of return ductworkNo Combustables

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

Metal DuctsSquare DuctworkMost commonLow heightRound DuctworkLess ExpensiveEasy to InstallLower static pressureTaller than RectangularHigher pressureLess SoundOval DuctworkSame advantages of roundHeight similar to rectangularMore expensive than rectangular

Fabric DuctsGreat for certain applicationsGymsPoolsManufacturingSpokane Science MuseumAdvantagesGreat DiffusionEasily CleanedFunSame cost as metal

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

Additional EquipmentHeat ExchangersHumidifiersSilencers

Kitchen HoodsType 1: Hoods designed for grease exhaust applicationsType 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 withNPFA 96-A-1-1 intended to include residential cooking equipment where used for purposes other than residential family useType 1 Hood Clearances18 inches to combustible material3 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.

Kitchen Hood TypesExhaust Hood w/ Supply Air Supplied by SpaceExhaust Hood w/Supply Air on Outside of HoodExhaust Hood w/Supply Air on Inside of HoodVapor HoodsSimple hoods designed to remove minimal heat, and high vapor.

ComfortComfort is primary intent of HVAC systems.ProductivityBuilding DurabilityHealthMold

ASHRAE Comfort Zone

PsychrometricsDry bulb temp.Wet bulb temp.HumidityDew pointMoisture contentHeatingCoolingHumidifyDe-Humidify

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

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183544Tredgold 1836

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186522.522.5Nightengale 1865

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Improved Ventilation EffectivenessMechanically provide filtered and dehumidified outdoor air to the breathing spaceVary 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 conditioningUtilize heat recovery systems to reduce system size and ventilation energy costs

Improved Ventilation EffectivenessEffective mixing of ventilation air within spaceNet positive pressure in the southeast; exhaust from appropriate spacesProvide clean outdoor air, avoid: loading docks exhaust vents plumbing stacks waste collection stagnant water

Acoustics

Octave Band

Directivity Factor

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

LEED Checklisthttp://www.metrokc.gov/dnrp/summit/documents/LEED-Spataro.pdf

http://www.metrokc.gov/dnrp/summit/documents/LEED-Spataro.pdf

THANK YOU!

Additional Information / ResourcesASHRAE The American Society of Heating, Refrigerating and Air-Conditioning Engineerswww.ashrae.orgSouthface Energy Institute www.southface.orgGeothermal heat pump consortium www.geoexchange.orgwww.buildingscience.comwww.energycodes.govHVAC Acoustics for Green Buildings Mike Filler. Ashrae technical committee for Sound and VibrationMcQuay Application Guide AG 31-010 HVAC Acoustic FundamentalsEnergy Efficiency in Buildings Dr. Sam C M Hui Department of Mechanical Engineering

***********Solar Heat Gain Coefficient (SHGC)The glazings effectiveness in rejecting solar heat gain.Part of a system for rating window performance used by the National Fenestration Rating Council (NFRC)Gradually replacing shading coefficient (SC) in product literature and design standards convert SC to SHGC by multiplying the SC value by 0.87

*******An HVAC system consists of a heating and/or cooling source, a distribution system (e.g. ductwork or hot/chilled water piping) and temperature controls.

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