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Lecture Objectives:

Lecture Objectives:. Model processes in AHU Use eQUEST predefined models Use detail modeling Define your topics for your final project. Where to look for info about eQUEST simulation tool . You will find more info about eQUEST at: eQUEST help file

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Lecture Objectives:

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  1. Lecture Objectives: • Model processes in AHU • Use eQUEST predefined models • Use detail modeling • Define your topics for your final project

  2. Where to look for info about eQUEST simulation tool You will find more info about eQUEST at: • eQUEST help file • User manual http://www.doe2.com/download/equest/eQUESTv3-Overview.pdf • Detail manual http://www.doe2.com/download/DOE-22/DOE22Vol1-Basics.pdf • eQUEST user blog http://www.doe2.com/equest/

  3. eQUEST HVAC Models • Predefined configuration (no change) • Divided according to the cooling and heating sources • Details in e quest help file: For example: DX CoilsNo Heating • Packaged Single Zone DX (no heating) • Packaged single zone air conditioner with no heating capacity, typically with ductwork. • Split System Single Zone DX (no heating) • Central single zone air conditioner with no heating, typically with ductwork. System has indoor fan and cooling coil and remote compressor/condensing unit. • Packaged Terminal AC (no heating) • Packaged terminal air conditioning unit with no heating and no ductwork. Unit may be window or through-wall mounted. • Packaged VAV (no heating) DX CoilsFurnace • Packaged direct expansion cooling system with no heating capacity. System includes a variable volume, single duct fan/distribution system serving multiple zones each with it's own thermostatic control. • Packaged Single Zone DX with Furnace • Central packaged single zone air conditioner with combustion furnace, typically with ductwork. • Split System Single Zone DX with Furnace • Central single zone air conditioner with combustion furnace, typically with ductwork. System has indoor fan and cooling coil and remote compressor/condensing unit. • Packaged Multizone with Furnace • Packaged direct expansion cooling system with combustion furnace. System includes a constant volume fan/distribution system serving multiple zones, each with its own thermostat. Warm and cold air are mixed for each zone to meet thermostat control requirements.

  4. Building Heating/Cooling System Plant Integration of HVAC and building physics models Load System Plant model Building Qbuiolding Heating/Cooling System Q including Ventilation and Dehumidification Plant Integrated models

  5. Schematic for model of simple air handling unit Mixing box m - mass flow rate [kg/s], T – temperature [C], w [kgmoist/kgdry air], r - recirculation rate [-], Q energy/time [W]

  6. Energy and mass balance equations for Air handling unit model – steady state case The energy balance for the room is given as: mS is the supply air mass flow rate cp- specific capacity for air, TRis the room temperature, TS is the supply air temperature. The air-humidity balance for room is given as: wRand wS are room and supply humidity ratio - energy for phase change of water into vapor The energy balance for the mixing box is: ‘r’ is the re-circulated air portion, TO is the outdoor air temperature, TM is the temperature of the air after the mixing box. The air-humidity balance for the mixing box is: wOis the outdoor air humidity ratio and wM is the humidity ratio after the mixing box The energy balance for the heating coil is given as: The energy balance for the cooling coil is given as:

  7. Non-air system Radiant panel heat transfer model

  8. Non-air system Radiant panel heat transfer model The total cooling/heating load in the room The energy extracted/added by air system The energy extracted/added by the radiant panel: The energy extracted/added by the radiant panel is the sum of the radiative and convective parts: The radiant panel energy is:

  9. Building Heating/Cooling System Plant Integration of HVAC and building physics models Load-System-Plant model does not work in cases when HVAC components radiate to other surfaces We have to use Integrated models: Qrad_plant T surrounding surfaces Tw_out T surrounding surfaces mw, Tw_in External weather parameters Solve simultaneously system of equation or use iterative procedure.

  10. Final project topics: Software based • Energy analysis of building form Integrated design course, • Envelope analysis of glass buildings • …. Detail Modeling (your model) • Heat recovery systems, • Economizers, • Water cooled chiller, • Geothermal heat pump, • Solar hot water systems, • Mass transfer (moisture, ozone, VOCs,…) • Vented cavity walls - exam problem • …. Your ideas

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