125BEPM, 125MOEB, MECB - cvut.cztzb.fsv.cvut.cz/files/vyuka/125meb,125mec/... · elements and thermal mass) ... Dynamic methods Forward ... –Convergence calculation – turbulent

1

2012/2013

© ČVUT v Praze, FSv K125 prof.Kabele

Czech Technical University in Prague Faculty of Civil Engineering

Department of Microenvironmental and Building Services Engineering

Czech Technical University in Prague Faculty of Civil Engineering

Department of Microenvironmental and Building Services Engineering

Building energy performance modelling Modelování energetických systémů budov

prof.Ing.Karel Kabele,CSc.

A227b

Lecture 1 Building and energy fundamentals

125BEPM, 125MOEB, MECB

• http://tzb.fsv.cvut.cz

• Pwd: cover

• Lectures + seminars, classified credit

125BEPM,MEB,MEC prof.Karel Kabele 2

http://tzb.fsv.cvut.cz/

2

2012/2013


Building Operation and Environment


Agency flows modelAgency flows model

–– OUTOUT –– WasteWaste gasesgases SOSO22 , CO, CO22 , N, NOOxx … …

((chimneychimney))

–– ININ –– WaterWater ((drink, drink, hygienehygiene, , washingwashing--upup, ,

cleaningcleaning, , flowersflowers, technology,, technology,rainrain……))

–– Energy: Gas, coal, timber, electricity.. Energy: Gas, coal, timber, electricity.. ((heating, cooling, cooking, lighting, heating, cooling, cooking, lighting, engins…engins…))

–– Air Air ((ventilation, cooling, combustionventilation, cooling, combustion))

–– Waste water (drainage) Waste water (drainage) –– Heat transmission (building envelope)Heat transmission (building envelope)

–– Waste airWaste air ((ventilation of the building)ventilation of the building)

Building and energy – Indoor environmental

quality (temperature, indoor air quality, lighting)

– Hygienic requirements (sanitary, hot water)

– Energy distribution (wiring, gas supply, technical gases)

– Operating and regulating systems in buildings (EPS, EZS, control, security)

– Systems of transport (elevators, escalators, travelators, tube post)

– Technological equipment (central vacuum cleaner, kitchen, laundry, pool)

125BEPM,MEB,MEC 5 prof.Karel Kabele

3

2012/2013


Introduction – Building and Energy


Annual energy use in the hotel (322 beds)

-

200

400

600

800

1 000

1 200

1 400

Mar

-01

Apr-0

1

May

-01

Jun-

01

Jul-0

1

Aug-0

1

Sep-0

1

Oct

-01

Nov

-01

Dec

-01

Jan-

02

Feb-

02

GJ/month

0

1000

2000

3000

4000

5000

6000

7000

gu

es

ts/m

on

th

Guests Space heating

Hot water AHU heat

Steam Kitchen

Laundry Cooling

Other technologies Lighting

Lifts

Annual energy use pie

Space heating

8%

AHU heat

14%

Hot water

14%

Cooling

11%Kitchen

6%

Laundry

11%

Steam

8%

Lifts

3%

Lighting

16%

Other

technologies

9%

Building energy performance assesment? „Low energy building“ 50 kWh/m2/a … heating only? New approach needed…

Average month temperatures in 2001

-5

0

5

10

15

20

25

Mar

-01

Apr

-01

May

-01

Jun-

01

Jul-0

1

Aug

-01

Sep

-01

Oct-0

1

Nov

-01

Dec

-01

Jan-

02

Feb-

02

Te

.mo

nth

av

era

ge

°C

What are we going to calculate?

125BEPM,MEB,MEC prof.Karel Kabele ©Sowa, 2001

Unit approach, UUnit approach, U-- valuevalue Heat losHeat loss/gains s/gains NNet energy for heatinet energy for heating/coolingg/cooling

Delivered energyDelivered energy Overlall eOverlall energy usenergy use COCO2 2 emissionsemissions

CO2

4

2012/2013


Reality

Real size models

Fig. 3. ESP-r model of the building

Fig. 3. ESP-r model of the building

Virtual models

Scaled models


Components of a mathematical model

(Beck and Arnold1977, cited in ASHRAE 2009)

Input variables:

Variables that act on the system. May be controllable

by the experimenter or uncontrollable (i.e. climate)

System structure and parameters/properties:

Provide the necessary physical description of the system (e.g. mechanical properties of the elements and thermal mass)

Output variables:

Describe the reaction of the system to the input variables (e.g.

energy use)


5

2012/2013


Modelling and simulation tools clasification


Building performance

modelling & simulation Method

Steady state

Dynamic

Scope

System Integrated

Data

Forward

Data - Driven

Purpose

Energy Comfort

Environment Sustainability

Steady – state methods

Forward

• Modified degree-day method – Based on fixed reference

temperature of 18.3°C.

• Variable-base degree-day method, or 3-P change point models – Variable base reference

temperatures

Data driven

• Simple linear regression – One dependent parameter, one

independent parameter. May have slope and y-intercept

• Multiple linear regression – One dependent parameter,

multiple independent parameters.

• Change-point models – Uses daily or monthly utility

billing data and average period temperatures


6

2012/2013


Dynamic methods Forward

• Simplified dynamic methods

– Regresive result analysis from multiple steady-state model run with variable boundary condition

• Weighting-Factor Method

– With this method, space heat gains at constant space temperature are determined from a physical description of the building, ambient weather conditions, and internal load profiles.

• Response factor

– Simple systems dynamic response is possible to describe by diferential equation. Fourier analysis. Frequency domain analysis convertible to time domain time. Analagy with electrical circuits – resitance, capacity, transformer. Thermal and electricity.

• Heat balance method

– Set of equations, describing energy flow paths between nodes (volumes), solved by numerical methods – finite diference method, finite element method

Forward

• Simplified dynamic methods

– Regresive result analysis from multiple steady-state model run with variable boundary condition

• Weighting-Factor Method

– With this method, space heat gains at constant space temperature are determined from a physical description of the building, ambient weather conditions, and internal load profiles.

• Response factor

– Simple systems dynamic response is possible to describe by diferential equation. Fourier analysis. Frequency domain analysis convertible to time domain time. Analagy with electrical circuits – resitance, capacity, transformer. Thermal and electricity.

• Heat balance method

– Set of equations, describing energy flow paths between nodes (volumes), solved by numerical methods – finite diference method, finite element method


Data-driven Artificial neural networks

Connectionist models.

Data-driven Artificial neural networks

Connectionist models.

Heat balance method • Wall • Wall


Outside face heat balance

Absorbed incident solar

Convection to outside air

LW radiation

Wall conduction

Inside face heat balance

SW radiation from lights

Transmitted solar LW radiation with other surfaces

LW radiation from internal sources

Convection to zone air

7

2012/2013


Heat balance method Wall with window Wall with window


Outside face heat balance

Absorbed incident solar

Convection to outside air

LW radiation

Wall conduction

Inside face heat balance

SW radiation from lights

Transmitted solar LW radiation with other surfaces

LW radiation from internal sources

Convection to zone air

Window

Reflected incident solar

Glazing

Heat balance method


Zone airZone air

Zone air heat balanceZone air heat balance

Infiltration

Ventilation Ventilation (HVAC)

Convection from internal sources

Convection from internal sources

Convection from wall 2 Convection from wall 2

Convection from wall 1 Convection from wall 1

Convection from wall … Convection from wall …

8

2012/2013


Tools clasification


Building Building SimulationSimulation

Whole Whole Building Building AnalysisAnalysis

ComponentsComponents

Other Other ApplicationsApplications

Energy Energy SimulationSimulation

Load Load CalculationCalculation

Renewable Renewable EnergyEnergy

Retrofit Retrofit AnalysisAnalysis

SustainablSustainable e BuildingsBuildings

Envelope Envelope SystemsSystems

HVACHVAC Lighting Lighting SystemsSystems

Atmospheric Atmospheric PollutionPollution

Energy Energy EconomicsEconomics

Indoor Air Indoor Air QualityQuality

VentilationVentilation AirAir flowflow

ESP-r ENERGY+ IES ECOTEC…

TRNSYS PVSol…

CFD…

Tools overview


http://www.eere.energy.gov/buildings/tools_directory/http://www.eere.energy.gov/buildings/tools_directory/ http://www.eere.energy.gov/buildings/tools_directory/http://www.eere.energy.gov/buildings/tools_directory/

http://http://www.ibpsa.orgwww.ibpsa.org http://http://www.ibpsa.orgwww.ibpsa.org

9

2012/2013


Design Builder for Energy+

Modeling and simulation of buildings (and systems)

Different levels of model detail

3D realistic model

Commercial tool/ free calculation kernel

prof.Karel Kabele 22 125BEPM,MEB,MEC

TRNSYS

Simulation buildings and energy systems

Open structure

Elements library

Commercial product


10

2012/2013


IDA

Modeling and simulation of Buildings and systems

Databases

Standard climate data files

Commercial tool


Computational Fluid Dynamics

• Modeling of indoor environment - air flow patterns, temperature distribution, polutantat concentration

– Aerodynamics of interior or exterior – Navier- Stokes equations – Temperature, pressure, air flow velocity and direction, radiatin – Convergence calculation – turbulent fows, symetry, sensitivity – Tools: Fluent, Flovent,ESP-r…

prof.Karel Kabele 25

125BEPM,MEB,MEC

Documents

125BEPM, 125MOEB, MECB - cvut.cztzb.fsv.cvut.cz/files/vyuka/125meb,125mec/... · elements and thermal mass) ... Dynamic methods Forward ... –Convergence calculation – turbulent