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Equation solvers. Matlab Free versions / open source codes: Scilab http://www.scilab.org/ MathCad: Mathematica: http://www.wolfram.com/mathematica/ LabView: http://www.ni.com/labview/ EES: http://www.fchart.com/ees/ Modelica: https://www.modelica.org/ …. Open Studio Lab Class.
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Equation solvers • Matlab • Free versions / open source codes: • Scilab http://www.scilab.org/ • MathCad: • Mathematica: http://www.wolfram.com/mathematica/ • LabView: http://www.ni.com/labview/ • EES: http://www.fchart.com/ees/ • Modelica: https://www.modelica.org/ • ….
Open Studio Lab Class • This Thursday 4 pm • Computer lab ECJ 3.402 • Instructor: Wesley Cole
Lecture Objectives: • Building-System-Plant connection
Building-System-Plant HVAC System (AHU and distribution systems) Plant (boiler and/or Chiller) Building
Building HVAC Systems (Primary and Secondary Building Systems) AHU – Air Handling Unit Distribution systems Fresh air For ventilation AHU Primary systems Air transport Electricity Secondary systems Cooling (chiller) Heating (boilers) Building envelope HVAC systems affect the energy efficiency of the building as much as the building envelope Gas (or Gas)
Roof top AHU fresh air filter mixing Fan air from building to building Evaporator Gas/Electric Heater Air-conditioning in Air Handling Unit (AHU) AHU AHU schematic Exhaust From room Return fan flow control dampers Supply fan Compressorand Condenser Fresh air To room Outdoor air hotwater coolwater
Processes in AHU presented in Psychrometric in psychrometric Case for Summer in Austin OA MA IA SA
Refrigeration Cycle Released energy (condenser) T outdoor air T cooled water - What is COP? - How the outdoor air temperature affects chiller performance? Cooling energy (evaporator)
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
Example of System Models:Schematic of simple air handling unit (AHU) Mixing box m - mass flow rate [kg/s], T – temperature [C], w [kgmoist/kgdry air], r - recirculation rate [-], Q energy/time [W]
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:
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: