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MATLAB Expo 2017Building and HVAC Simulation inMATLAB/Simulink – FFG Project SaLüH!Fabian Ochs, Dr.-Ing.Dietmar Siegele, DI, MScGeorgios Dermentzis, DIEleonora Leonardi, MScToni Calabrese, MScFelix BartagnoliMunich, June 2017

Building and HVAC Simulation in MATLAB/Simulink 08.06.2017ThermolibHambase/Hamlab (van Schindel TUE) ComsolSimbad (CSTB)International Building Physics Toolbox www.ibpt.orgCarnot Toolbox Fabian Ochs2

Simulink, Carnot BlocksetUser/Developer (next User Meeting Feb. 2018) 08.06.2017Companies such as Vaillant, ViessmannSIJ, FH AachenFHNW, HS RapperswilFH IngolstadtRWTH AachenUni BayreuthTU DarmstadtTU DortmundASICUni BolognaUni Innsbruck Fabian Ochs3

Scope of Building and HVAC SimulationInvestigation of Thermal Comfort (operative temperature Jop, relative humidity) Indoor Air Quality (IAQ): CO2, VOC, PM, etc. Visual Comfort / glare protection (in non-residential buildings) Building Performance - Heating Demand (HD), Cooling Demand(CD), Heating Load (HL), Cooling Load (CL) 100 System Performance ( Control Optimization) Primary Energy Savings / Reduction ofCO2-emission8070 / [%] (On-site) use of Renewables, load le906050403020 Economic Analysis (LCC)1001416182022242628J / [ C]08.06.2017Fabian Ochs4

Renovation of small Flats with decentralVentilation and Heating System andDHW Heat Pump (FFG Project) Most buildings are poor energy performance buildings Renovation plays a key role in achieving required reduction of CO2emissions Envelope solutions are available (insulation, windows, etc.) Renovations in MFHs are frequently done flat-wise Non-disruptive solutions for renovation the HVAC system are required Heat Pumps represent an alternative to electric heating and DHWpreparation (in case gas or district heat not applicable)08.06.2017Fabian Ochs5

Example of a small flat in atypical Multi Family House (MFH)Floor Plan and SectionN3 rooms, kitchen, bathroom, ca. 70 sqm08.06.2017Fabian Ochs6

Example of a small flat in a Multi Family House (MFH) Flat-wise Renovation Frequently no heat emission system No space for technical installations As a consequence:Frequently electric heating andDHW preparation08.06.2017Fabian Ochs7

Compact Heat Pumps for RenovationExhaust Air Heat Pump with ERVSecondary airExtract airSupply airAmbient airExhaust airCompact DHW Heat Pump withoptionally facade integrated modular storage08.06.2017Fabian Ochs8

„XL“ compact units for „large“ PHEffiziento HTZ 4x² von drexel und weissZehnder ComfoBoxVP 18 Compact von NilanNot applicable in small flats!08.06.2017AEREX BW 175LWZ 304 SOL von Stiebel EltronMarkus Meyer, Kompakt und komfortabel Lüftungskompaktanlagen und Alternativen für das PassivhausFabian Ochs9

Mini-Split / Multi-SplitExample of Mini-Split http://www.toshiba-klima.de/Fabian Ochs10

Single Split / Multi Split Heating and cooling with one device Various indoor unit designs Rel. good performance (SCOP 3) Heating capacity from 2.5 to 12 kW Flexible design Rel. high cost for multi-split Challenging heat distribution for single split in combination with radiant heater08.06.2017Fabian Ochs11

Multi-Split UnitMulti-Splits:several indoor and one outdoor unit: Individual temperature control- Performance- rel. high costadditional bathroom radiator(towel dryer, convector, radiant heater)MVHR not depictedVRF for simultaneous heating and cooling(heat recovery)08.06.2017Fabian Ochs12

Heating with single Split Unit (Overheating of Corridor)Mini-Splitwith radiant heater low sound emissions outside Individual room control- Performance (electric heating)additional bathroom radiatorElectric post heater forindividual room control(towel dryer, convector, radiantheater)MVHR not depicted08.06.2017Fabian Ochsambient13

Compact Systems for Façade IntegrationExtraxt airAmbient airSupply airExhaust airMVHR with exhaust air heatpump (with hot gas bypass fordeicing)08.06.2017Functional Model and iNSPiRe Demo-Building,Ludwigsburg (WB-L, G M)EU-project iNSPiRe (fp7)Fabian Ochs14

Supply Air Heat Pump (façade integrated)with radiant heaterSupply air heating (with MVHR)for PH Rel. low costs- No individual room control- Performanceadditional bathroom radiator(towel dryer, convector, radiant heater)MVHR with Micro-HP08.06.2017Fabian Ochs15

Supply Air Heat Pump (façade integrated)with radiant heaterSupply air heating (with MVHR) Higher heating power (EnerPhit) Individual room control- Higher costs- Lower performance (electric heating)additional bathroom radiator(towel dryer, convector, radiant heater)MVHR with Micro-HP08.06.2017Fabian Ochs16

Supply Air Heat Pump with recirculationSupply air heating (with MVHR)for EnerPHit higher heating power (EnerPHit)- Higher installation effort (ducts)additional bathroom radiator(towel dryer, convector, radiant heater)MVHR with Micro-HP with additional ambient air08.06.2017Fabian Ochs17

Concept of Ventilation and Heating SystemAUSEKABSEKZUFOOutdoor Unit08.06.2017HRV/ERVABZUIndoor UnitFabian Ochs18

Heating Load and Supply Air Heating Maximum heating load withsupply air heating per room: 20W/m²sleeping20 W/m²kitchen Heating load only via supply airrooms Hygienic flow rate!corridor50 W/m² Maximum heating load withrecirculation air: 50 W/m² Overheating: approx. 1 K08.06.2017bathFabian Ochssleepingliving20 W/m²20 W/m²19

Temperature-Enthalpy Diagramand Psychrometric Chart up0exh1exh0exh11amb4sup0sup1Simulation of refrigerant cycle and moist air properties with MATLAB and CoolProp08.06.2017Fabian Ochs20

Temperature-Enthalpy Diagramand Psychrometric Chart xh0sup0exh0exh1sup1exh11amb4Simulation of refrigerant cycle and moist air properties with MATLAB and CoolProp08.06.2017Fabian Ochs21

Example: Reference Building/Flat– Project SaLüH!3 Variants08.06.2017Fabian Ochs22

Zoning - Section and simplfied schemeunheatedattic: BCsingle pe“detailed flatsimulationunheatedcellar: BC 2, 3 or more zones08.06.2017Fabian Ochs23

Zoning - Section and simplfied schemeunheatedattic: BCunheatedstaircase„insideenvelope“single zoneflatsimulationdetailed flatsimulationwith 5 or 6zonesunheatedcellar: BC 5 or 6 zones for flat 1 or 2 zone for building08.06.2017Fabian Ochs24

Building Model Physics – Performance and Accuracy Model Physics (Radiation) Two-Star Star-Node Radiosity (physics) Model Physics (Convection) Ideally mixed Stratified CFD Model Physics (Transmission) Transfer Function R-C wall 2D/3D (FD or FE) Model Physics (Window) Humidity Hygrothermal wall08.06.2017 Moisture Buffer Air Quality CO2 VOC Heat Emission Model Radiator Radiant Ceiling/Floor Fan Coil) HVAC Look up Table Black Box Model Physical ModelFabian Ochs25

Model Physics - Convective Nodefully mixedconvectiveceilingRradJSJRJCRcombRconvJcJTwo star modelfloorStar-node modely08.06.2017Fabian Ochs26

Model Physics - Radiation Exchange Two star and Star node model Non-physical Radiation exchange with virtualradiation Sufficiently accurate dynamics Sufficiently accuraterepresentation of operativetemperatureRradJSJRJCRconvJcTwo star model Radiosity Model Physically correct Radiation exchange fromsurface to surface Spatial distribution of radiativetemperature Radiation temperature asymmetry Possibility to predict localcomfort08.06.2017RcombFabian OchsStar-node modelA1hbaA2View factor between asurface and a sphere27

3D-Model in Comsol Multiphysics (FE-Model)Result: View Factor08.06.2017Fabian Ochs28

Multi-Zone Simulation with Air-Coupling inMATLAB/Simulink11.2Forced Convection between Zones(Ventilation)3322.1Zone 1Natural Convection between Zones (incase of open doors)33.Zone 2Air exchange betweenthermal zonesInfiltration and Exfiltration𝑚 𝐶 𝑃 𝑛 𝑃 𝜌 𝑔 𝐶 0.5 𝐶𝑑 08.06.2017Fabian Ochs2 2 𝐿 𝜌29

Hygrothermal Wall ModellEnergy Conservation and Mass ConservationCoupled system of ODEssolved with MATLAB pdepe functionand MATLAB/Simulink S-function08.06.2017Fabian Ochs30

PDE for Simulink Simulink solves ODEs Generate system of ODE from PDE with „Method of Lines“ Update of PDE Parameter with time Integration by SimulinkStatesPDE ProblemSimulink BlockInputOutputone for each nodetransient BC, SourceTemperature at eachnodeSource: Ochs et al. 2012, Bausim, BerlinPrüfert, TUB, 201208.06.2017Fabian Ochs31

Modelling Ground Heat Exchanger2D heat equation, cylinder coordinatesr c p J r J J q r t r r z z (PDE)MATLAB/SimulinkMethod of linesPDE ProblemLevel 2s-function(Matrix Formulation)dU M 1 F G R KU QU HU dtLevel 2 SfunctionInitializationStatesOne for each nodeInputTime depended BC,Output08.06.2017Fabian OchsSimulink BlockTemperature at singlenode, heat flux32

Example: Facade integrated MHVROther examples of 2 DHeat Transfer: Ground coupling (2D) Thermal Bridges (2D) Ground heat exchanger08.06.2017Fabian Ochs33

MATLAB/Simulink Building Model (Object Oriented)08.06.2017Fabian Ochs34

Multi-Zone Building inMATLAB/Simulink08.06.2017Fabian Ochs35

Temperature Distribution - SaLüH! Reference BuildingSupply Air Heating (no recirculation), no bath heater23KücheWohnzimmerSchlafen SüdSchlafen NordGangBad22.522Temperatur / [ 05000Zeit / [h]Fabian Ochs60007000800036

Overheating of corridorDoor air exchange model: BR/CHILD/SLEEP (Closed), KITCH/LIVING (Opened)Individual (room-wise) post-heater08.06.2017No individual (room-wise) post-heaterFabian Ochs37

Simulation Results – Heating demand and heating loadHEATING DEMAND[kWh/m²a]SimulationREFCorridor Overheating(24 C)Corridor Overheating„symmetric BC“Corridor Overheating„symmetric BC“No room post-heaterTotalHEATING LOAD [W/m²]SupplyairElectr.HeaterAir .017.80.023.823.80.013.30.022.922.9010.6Door air exchange model: 08.06.2017BR/CHILD/SLEEP (Closed), KITCH/LIVING (Opened)Fabian Ochs38

Research Projects EU iNSPiRe (fp7)Landesförderung Tirol k-WPFFG SaLüH!NHT VögelebichlIEA SHC Task 56IEA HPT Annex 49AcknowledgementsThis work is part of the Austrian research project SaLüH!Renovation of multi-family houses with small apartments, lowcost technical solutions for ventilation, heating & hot water (201518); Förderprogramm Stadt der Zukunft, FFG, Project number:850085.A detailed report on the review of heat pumps in passive housesis available German language and can be distributed on request.08.06.2017Fabian Ochsthanks to Siko Energiesysteme (At)Pichler Luft (At)Gumpp & Maier (D)Wohnungsbau Ludwigsburg (D)Eurac (It)AEE Intec (At)Vaillant (D)NHT (At)39

Simulation Results -Heating demand and heating load Simulation HEATING DEMAND [kWh/m²a] HEATING LOAD [W/m²] Supply air Electr. Heater Total Air heating Electr. Heater REF 24.8 3.4 28.2 13.2 5.1 Corridor Overheating (24 C) 0.0 48.1 48.1 0.0 17.8 Corridor Overheating „symmetric BC" 0.0 23.8 23.8 0.0 13.3 Corridor Overheating .