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Thermally Activated Building Systems (TABS) Lecture "Building Control and Automation", part "Building Automation" Author: Dr. Conrad Gähler Revision: 1.0, 18-Mai-2015

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Page 1: Lecture Building Control and Automation, part Building ...control.ee.ethz.ch/~building/docs/BA_TABS.pdf · Thermally Activated Building Systems (TABS) Lecture "Building Control and

Thermally Activated BuildingSystems (TABS)

Lecture "Building Control and Automation", part "Building Automation"

Author: Dr. Conrad GählerRevision: 1.0, 18-Mai-2015

Page 2: Lecture Building Control and Automation, part Building ...control.ee.ethz.ch/~building/docs/BA_TABS.pdf · Thermally Activated Building Systems (TABS) Lecture "Building Control and

Rev 1.0, 18-Mai-2015Page 3 / 18 Dr. Conrad Gähler

BuildingAutomation

Thermally Activated Building Systems (TABS)D: Thermoaktive Bauteilsysteme (TABS)

Principle• TABS are large-area systems for heat and cool transfer• They may be integrated in the building structure or attached to it

(D: aufgesetzt)• The systems use the concrete core of the buildings, usually the floor slabs,

for climatisation• Room heating and cooling is achieved either by means of TABS alone, or

with additional systems (e.g. radiators)

Page 3: Lecture Building Control and Automation, part Building ...control.ee.ethz.ch/~building/docs/BA_TABS.pdf · Thermally Activated Building Systems (TABS) Lecture "Building Control and

Rev 1.0, 18-Mai-2015Page 4 / 18 Dr. Conrad Gähler

BuildingAutomation

Thermally Activated Building Systems (TABS)Advantages

Exploiting natural energy resources• Small temperature differences between flow and room temperaturesà energy efficient solutions are possible(heating with high COP; free cooling)

“Self-control effect”• Small temperature differences (TFlow-TR) offer comparatively moderate

potential for overheating

Using the big thermal storage of TABS• The big thermal storage capacity of TABS makes it possible to separate in

time heat/cold demand and heat/cold preparation.• ð energy-efficient solutions, e.g.

• free cooling at night• intermittent operation of the heating circuit pumps• accommodating solar thermal energy• heating with heat pump when electricity is cheap

Page 4: Lecture Building Control and Automation, part Building ...control.ee.ethz.ch/~building/docs/BA_TABS.pdf · Thermally Activated Building Systems (TABS) Lecture "Building Control and

Rev 1.0, 18-Mai-2015Page 5 / 18 Dr. Conrad Gähler

BuildingAutomation

Thermally Activated Building Systems (TABS)Restrictions

Restricted freedom for constructions of floors and ceilings (D: Decken-und Bodenaufbauten)

• Close thermal coupling between TABS and room air is requiredà Conflicts with hollow floors, abgehängten Decken, acoustic isolation, …

No arbitrary requirements to thermal comfort• A rise of TR during the day must be accepted

Demanding HVAC planning process• Knowledge of building usage required• Acceptance of the 2 above-mentioned points must be secured• Integrated Planning of the HVAC system and its control (dynamic sizing)

Conventional control strategies are not sufficient• Conventional control strategies, in particular for TR control, do not work

satisfactorily• TABS has a very high thermal inertia• Tricky changeover between heating and cooling operation

Page 5: Lecture Building Control and Automation, part Building ...control.ee.ethz.ch/~building/docs/BA_TABS.pdf · Thermally Activated Building Systems (TABS) Lecture "Building Control and

Rev 1.0, 18-Mai-2015Page 6 / 18 Dr. Conrad Gähler

BuildingAutomation

CTI / KTI research project “TABS Control”

Project duration• 2004 – 2008

Partners

• Energiesysteme/Haustechnik

• ZIG Zentrum für Integrierte Gebäudetechnik

• Building Technologies

Page 6: Lecture Building Control and Automation, part Building ...control.ee.ethz.ch/~building/docs/BA_TABS.pdf · Thermally Activated Building Systems (TABS) Lecture "Building Control and

Rev 1.0, 18-Mai-2015Page 7 / 18 Dr. Conrad Gähler

BuildingAutomation

TABS plant with control:Structure

§ Separation in consumer, distribution andproduction of heat and cold

§ Separation of consumer (rooms) in zones(typically 2-3 zones per building)

§ Separation of the control task in zonecontrol, control of heat/cold distributionand control of heat/cold production

Page 7: Lecture Building Control and Automation, part Building ...control.ee.ethz.ch/~building/docs/BA_TABS.pdf · Thermally Activated Building Systems (TABS) Lecture "Building Control and

Rev 1.0, 18-Mai-2015Page 8 / 18 Dr. Conrad Gähler

BuildingAutomation

TABS plant with control:Zone control

A simple way of zone control:Outside air temperature compensatedflow temperature control

Cooling curve

Heating curve

Hea

ting

limit

Coo

ling

limit

Heating orOff

Heating or CoolingOr Off

Coolingor Off

Outside temp.

Zone flow temp.setpoint

TFlow is confined to liebetween heating andcooling curves:• TRet<HCrvà Heating• TRet>CCrvà Cooling• Else neither; but pump may

be on for balancing heatbetween different rooms /zones

Page 8: Lecture Building Control and Automation, part Building ...control.ee.ethz.ch/~building/docs/BA_TABS.pdf · Thermally Activated Building Systems (TABS) Lecture "Building Control and

Rev 1.0, 18-Mai-2015Page 9 / 18 Dr. Conrad Gähler

BuildingAutomation

CTI project “TABS-Control”, project results:Unknown-but-bounded (UBB) approach forparameterization of heating / cooling curve

Principle• TABS / TABS control cannot compensate for variations in internal heat load at short

notice• Heat loads cannot be predicted exactly, but upper and lower bounds for their (daily)

average can be assumed• Based on this, parameterize

• the heating curve such that TR does not go below TRSpH (e.g.21°C) in case wherethe internal het gains are at the lower bound

• the cooling curve such that TR does not exceed TRSpC (e.g.25°C) in case wherethe internal heat gains are at the upper bound

• Only feasible if tolerance band is sufficiently wide and uncertainty of loads is sufficientlysmall!

Page 9: Lecture Building Control and Automation, part Building ...control.ee.ethz.ch/~building/docs/BA_TABS.pdf · Thermally Activated Building Systems (TABS) Lecture "Building Control and

Rev 1.0, 18-Mai-2015Page 10 / 18 Dr. Conrad Gähler

BuildingAutomation

CTI project “TABS-Control”, project results:Unknown-but-bounded (UBB) approach forparameterization of heating / cooling curve

Principle1. For the lower bound of the heat gain progression it is

computed by means of simulation what is the minimal liftto TR that it causes in the course of a day when cyclicallyapplied (every day for a long time).

2. Then from the lowest TR lift an “equivalent lower heat gainbound” is computed that would cause the same minimalTR lift for the whole day

3. The heating curve is parameterized such that TR nevergoes below TRSpH assuming that the heat gainsconstantly equal the “equivalent lower heat gain bound”

4. For the upper bound of the heat gain progression themaximal TR lift is computed

5. From the highest lift, the “equivalent upper heat gainbound” is computed

6. The cooling curve is parameterized such that TR neverexceeds TRSpC with “equivalent upper heat gain bound”

Especially for office buildings, this procedure must be carriedout for a weekly (instead of daily) period, including weekends.

0

5

10

15

20

25

30

35

0 6 12 18 24

hour of day [h]

heat

gain

boun

ds[W

/m2 ]

lower bound

upper bound

0

1

2

3

4

5

0 6 12 18 24

hour of day [h]

Room

tempe

ratu

reinc

rease

[K]

lower bound

upper bound

2.6

K

2 14 5

Heat

gain

boun

ds[W

/m2 ]

Roo

mte

mpe

ratu

rein

crea

se[K

]

Hour of day [h]

Hour of day [h]

Page 10: Lecture Building Control and Automation, part Building ...control.ee.ethz.ch/~building/docs/BA_TABS.pdf · Thermally Activated Building Systems (TABS) Lecture "Building Control and

Rev 1.0, 18-Mai-2015Page 11 / 18 Dr. Conrad Gähler

BuildingAutomation

CTI project “TABS-Control”, project results:The modular TABS-Control zone control

… extension of the TO-compensated flow temp. control

oaJSpH,rJ

SpC,rJ

rJFB,SpH,rJ

FB,SpC,rJSpH,swJ

SpC,swJPWM,SpH,swJ

PWM,SpC,swJoaJ

Sp,swJ

swJ

sw,MaxJ

sw,MinJ swJ

12 3 4

• Basic modules: 1 “Heating/ cooling curve” and4 “Sequence Control”

• Optional for improving comfort: Module 2 “TRcontrol” (TR control on day-to-day basis)

• Optional for improving energy efficiency:Module 3 “Intermittent operation”à Research question: How well does coolingwith 24h cycling work? (à Profit from low TO atnight and use of free cooling when possible!)

Page 11: Lecture Building Control and Automation, part Building ...control.ee.ethz.ch/~building/docs/BA_TABS.pdf · Thermally Activated Building Systems (TABS) Lecture "Building Control and

Rev 1.0, 18-Mai-2015Page 12 / 18 Dr. Conrad Gähler

BuildingAutomation

CTI project “TABS-Control”, module for intermittentoperation: 1. Modelling

swJf,lR

cJ

rJ

oaJ

tR

auxg qq && +0,1sR

1,1sR

2,1sR

1n,1sR

1,2sR

2,2sR

2n,2sR

0,2sR

0,iwR

1,iWR

2,iWR

niW,iWR

rJ

rC

1,1sC

2,1sC

1n,1sC

1,2sC

2,2sC

2n,2sC

1,iWC

2,iWC

niW,iWC

0,1uR

1,1uR

2,1uR

1n,1uR

1,2uR

2,2uR

2n,2uR

0,2uR

1,1uC

2,1uC

1n,1uC

1,2uC

2,2uC

2n,2uC

Finite Element MethodHigh order modelFirst order model

R~swJ

f,lRtR

rJoaJ

cJ

auxg qq && +

sC

Sim

plifi

catio

nValidation

Laboratory / reality

Sim

plifi

catio

n

Simplification

Page 12: Lecture Building Control and Automation, part Building ...control.ee.ethz.ch/~building/docs/BA_TABS.pdf · Thermally Activated Building Systems (TABS) Lecture "Building Control and

Rev 1.0, 18-Mai-2015Page 13 / 18 Dr. Conrad Gähler

BuildingAutomation

CTI project “TABS-Control”, module for intermittent operation:2. Design / simulation using Closed- Loop Model inSimulink

High order model

Control incl.pulse width modulation

based on first order model

Weather data(measurements),

internal heat gains

Page 13: Lecture Building Control and Automation, part Building ...control.ee.ethz.ch/~building/docs/BA_TABS.pdf · Thermally Activated Building Systems (TABS) Lecture "Building Control and

Rev 1.0, 18-Mai-2015Page 14 / 18 Dr. Conrad Gähler

BuildingAutomation

Implementation / definition HMI

CTI project “TABS-Control”, module for intermittent operation:3. Implementation of control functionality

Parameter Value(example)

Period of heatingPWM operation

4 h

Period of coolingPWM operation

24 h

Period of unknownPWM operation

4 h

Maximum correctionof flow temperaturesetpoint

1.5 K

Minimal purgeoperation time

20 min

Minimal pumpswitch-on time

1 min

Minimal pumpswitch-off time

1 min

PWM thermalresistance ratio

40 %

Page 14: Lecture Building Control and Automation, part Building ...control.ee.ethz.ch/~building/docs/BA_TABS.pdf · Thermally Activated Building Systems (TABS) Lecture "Building Control and

Rev 1.0, 18-Mai-2015Page 15 / 18 Dr. Conrad Gähler

BuildingAutomation

Lab tests in TABS test room, Siemens HVAC Laboratory

CTI project “TABS-Control”, module for intermittent operation:4. Lab tests: HVAC Lab

Test room from outside

Test room from inside

Heat loads = simulated persons

Page 15: Lecture Building Control and Automation, part Building ...control.ee.ethz.ch/~building/docs/BA_TABS.pdf · Thermally Activated Building Systems (TABS) Lecture "Building Control and

Rev 1.0, 18-Mai-2015Page 16 / 18 Dr. Conrad Gähler

BuildingAutomation

CTI project “TABS-Control”, module for intermittent operation:Lab test: Cooling in 24 hours PWM operation

Room temperature androom temperature setpoint range

Temperature in weather zone

Purge operation (= pump onbut no heat removal from water circuit)

Flow temp., return temp.and flow temp. setpoint rangePump command

Heat gains

Weekend withreduced thermal load

End time of night cooling is computed usinga model such that TR remains withintolerance band on the next day

Page 16: Lecture Building Control and Automation, part Building ...control.ee.ethz.ch/~building/docs/BA_TABS.pdf · Thermally Activated Building Systems (TABS) Lecture "Building Control and

Rev 1.0, 18-Mai-2015Page 17 / 18 Dr. Conrad Gähler

BuildingAutomation

Download from: www.faktor.ch/?page=tabs

HauptresultateKombination Raumtyp: 1

Wärmegewinnschrankenprofil: 1

RaumtemperatursollwerteOberer Raumtemperatursollwert J r,SpC 24.5 °C ZusatzsystemUnterer Raumtemperatursollwert J r,SpH 21 °C TypAuslegungstemperaturen Min. Breite VorlauftemperatursollwertbandAuslegungaussentemperatur Kühlfall J oa,DsC 30 °C für TABS (falls Zusatzsystem) 0.5 KAuslegungaussentemperatur Heizfall J oa,DsH -10 °C

Zulässige Abweichungen vom Komfortbereich Mo Di Mi Do Fr Sa So WocheZulässige Überschreitungen bei oberer Wärmegewinnschranke 0 0 0 0 0 0 0 Kh 0 KhZulässige Unterschreitungen bei unterer Wärmegewinnschranke 0 0 0 0 0 0 0 Kh 0 Kh

Äquivalente WärmegewinnschrankeschrankenObere äquivalente Wärmegewinnschranke q g,eub 18.4 18.4 18.4 18.4 18.4 8.6 8.6 W/m2 18.3 W/m2

Untere äquivalente Wärmegewinnschranke q g,elb 4.3 4.3 4.3 4.3 4.3 1.1 1.1 W/m2 1.8 W/m2

Kühlkurve TABSKühlgrenze: Vorlauftemperatursollwert J sw,SpLmC 23.1 23.1 23.1 23.1 23.1 23.9 23.9 °C 22.7 °CKühlgrenze: Aussentemperatur J oa,LmC -5.8 -5.8 -5.8 -5.8 -5.8 9.8 9.8 °C -2.1 °CAuslegung Kühlen: Vorlauftemperatursollwert J sw,SpC,Ds 19.2 19.2 19.2 19.2 19.2 21.7 21.7 °C 19.2 °CAuslegung Kühlen: Rücklauftemperatur J rw,C,Ds 20.4 20.4 20.4 20.4 20.4 22.4 22.4 °C 20.5 °CHeizkurve TABSHeizgrenze: Vorlauftemperatursollwert J sw,SpLmH 21.7 21.7 21.7 21.7 21.7 21.0 21.0 °C 21.8 °CHeizgrenze: Aussentemperatur J oa,LmH 4.8 4.8 4.8 4.8 4.8 18.2 18.2 °C 9.1 °CAuslegung Heizen: Vorlauftemperatursollwert J sw,SpH,Ds 23.3 23.3 23.3 23.3 23.3 24.1 24.1 °C 23.9 °CAuslegung Heizen: Rücklauftemperatur J rw,H,Ds 22.7 22.7 22.7 22.7 22.7 23.2 23.2 °C 23.1 °C

Breite Vorlauftemperatursollwertband TABSVorlauftemperaturdifferenz Kühlkurve-Heizkurve DJ sw,Sp 0.3 0.3 0.3 0.3 0.3 2.0 2.0 K -0.3 KMin. Breite Raumtemperatursollwertband (ohne Zusatzsystem)Minimale Raumtemperatursollwertbreite (DJ sw,Sp =0 ) DJ r,SpMin 3.3 3.3 3.3 3.3 3.3 1.7 1.7 K 3.8 KWärmegewinnschrankeunsicherheitMax. zulässige Wärmegewinnspanne (ohne Zusatzsystem) D q g,Max 15.2 15.2 15.2 15.2 15.2 15.2 15.2 W/m2 15.2 W/m2

Effektive äquivalente Wärmegewinnspanne D q g,eq 14.1 14.1 14.1 14.1 14.1 7.5 7.5 W/m2 16.5 W/m2

Relative Wärmegewinnspanne r q 0.9 0.9 0.9 0.9 0.9 0.5 0.5 - 1.1 -Kann Komfort auch ohne Zusatzsystem eingehalten werden? ü ü ü ü ü ü ü û

Rücklauftemperaturdifferenz für obere Wärmegewinnschranke DJ rw,ub 0.28 0.28 0.28 0.28 0.28 0.11 0.11 K 0.5 K

Leistungsbedarf TABSMax. Kühlleistungsbedarf (Auslegungaussentemperatur) q w,DsC,ub -17.1 -17.1 -17.1 -17.1 -17.1 -9.4 -9.4 W/m2 -17.0 W/m2

Max. Heizleistungsbedarf (Auslegungaussentemperatur) q w,DsH,lb 7.5 7.5 7.5 7.5 7.5 12.0 12.0 W/m2 11.1 W/m2

Leistungsbedarf ZusatzsystemMax. Kühlleistungsbedarf (Auslegungaussentemperatur) q aux,DsC,ub 0.0 0.0 0.0 0.0 0.0 0.0 0.0 W/m2 0.0 W/m2

Max. Heizleistungsbedarf (Auslegungaussentemperatur) q aux,DsH,lb 0.0 0.0 0.0 0.0 0.0 0.0 0.0 W/m2 0.0 W/m2

Parameter Gebäudeautomationssystem DesigoSiemens Building TechnologiesHeizsollwert nominale Raumtemperatur SpHTRNom 21 °C 21 °CKühlsollwert nominale Raumtemperatur SpCTRNom 24.5 °C 24.5 °CAussentemperatur für nominale Heizgrenze TOaHLmNom 4.8 °C 9.1 °CAussentemperatur für nominale Kühlgrenze TOaCLmNom -5.8 °C -2.1 °CAuslegungsaussentemperatur Heizen TOaDsgnH -10 °C -10 °CHeizsollwert Vorlauftemp. für die Auslegungsaussentemperatur SpHTFlDs 23.3 °C 23.9 °CAussentemperatur oben für Heizen TOaHiH 4.8 °C 9.1 °CHeizsollwert Vorlauftemp. für obere Aussentemperatur SpTFlHi 21.7 °C 21.8 °CDelta Sollwert nominale Vorlauftemperatur DSpTFlNom 0.27 K -0.34 KDelta Heizsollwert Vorlauftemperatur DSpHTFl 0.0 0.0 0.0 0.0 0.8 0.8 KDelta Kühlsollwert Vorlauftemperatur DSpCTFl 0.0 0.0 0.0 0.0 2.5 2.5 K

Taktbetriebsparameter RthRatio 38.0%

Kein Zusatzsystem

ganze WocheAuswertung für Einzeltage

Heiz/Kühlkurve für ganze Woche

18

19

20

21

22

23

24

25

26

27

28

-15 -10 -5 0 5 10 15 20 25 30 35

Aussentemperatur [°C]

Vor

lauf

tem

pera

turs

ollw

ert[

°C]

Heizkurve

Kühlkurve

Heizgrenze

Kühlgrenze

Berechnung starten(alte Werte werden überschrieben)

Berechnete Werte löschen

Heiz/Kühlkurve für Montag / Sonntag

18

19

20

21

22

23

24

25

26

27

28

-15 -10 -5 0 5 10 15 20 25 30 35

Aussentemperatur [°C]

Vorl

aufte

mpe

ratu

rsol

lwer

t[°C

]

Heizkurve MontagKühlkurve MontagHeizgrenze MontagKühlgrenze MontagHeizkurve SonntagKühlkurve SonntagHeizgrenze SonntagKühlgrenze Sonntag

CTI project “TABS-Control”, project results:Planning tool TABSDesign

Page 17: Lecture Building Control and Automation, part Building ...control.ee.ethz.ch/~building/docs/BA_TABS.pdf · Thermally Activated Building Systems (TABS) Lecture "Building Control and

Rev 1.0, 18-Mai-2015Page 18 / 18 Dr. Conrad Gähler

BuildingAutomation

Handbuch TABS Control - Steuerungund Regelung von TABS (publishedMarch 2009)

Available from Faktor-Verlag:www.faktor.ch

Further publications (selection)

• “Control of Thermally Activated Building Systems”,CLIMA 2007 Helsinki

• “Integrated Design of Thermally Activated BuildingSystemsAnd of Their Control",CLIMA 2007 Helsinki

• “Effect of the Hydraulic Piping Topology on EnergyDemand and Comfort in Buildings with TABS”,CLIMA 2007 Helsinki

• “Control of Thermally Activated Building Systems”,Applied Energy 2008

• “Control of Thermally Activated Building Systems inintermittent operation with pulse width modulation”,Applied Energy 2009

CTI project “TABS-Control”, project results:Handbook “TABS Control”