Transcript PRIMENA TRODIMENZIONE METODE KONAČNIH ELEMENATA U …

35. MEĐUNARODNI KONGRES
O KLIMATIZACIJI, GREJANJU
I HLAĐENJU
Beograd, 1-3. decembra 2004.
35th CONGRESS ON AIR
CONDITIONING, HEATING
AND REFRIGIRATING
Belgrade, December 1-3, 2004
PRIMENA TRODIMENZIONE METODE KONAČNIH
ELEMENATA U PROCENI ENERGETSKE
EFIKASNOSTI OMOTAČA ZGRADE
ON THE THREEDIMENSIONAL FINITE ELEMENT
METHOD IN THE ENERGY EFFICIENCY OF
BUILDING’S ENVELOPE
Dr Dubravka Mijuca*, Dr Dušan Gajić**, Marko Vukobrat**
*Matematički fakultet, Univerzitet u Beogradu, P. FAH 550
**Institut "Kirilo Savić", Beograd
[email protected]
ENERGIJA KOJA SE TROSI U ZGRADAMA
BUILDING ENERGY USE
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Na energiju koja se koristi u zgradama (za zagrevanje,
hladjenje, osvetljavanje, i zadovoljavanje drugih važnih
energetskih usluga) otpada oko ¼ celokupne energije
upotrebljene u centralnoj i istočnoj Evropi
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Energy used in buildings (to heat, cool, light, and
provide other important energy services) accounts for
about one-fourth to one-third of all energy used in
Central and Eastern Europe.
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MOTIV - MOTIVE
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Projektovanje građevinskih objekata primenom
savremenih metoda računske mehanike je danas brže,
efikasnije i jeftinije, a strukturalni kvalitet i energetska
efikasnost projektovanog, rekonstruisanog ili
revitalizovanog objekta se njenom primenom povećava.
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Contemporary design in the civil engineering becomes
shorter in time, more efficient and less expensive by the
use of numerical methods of computational mechanics,
while structural quality and energetic efficiency are
increased
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CILJ - GOAL
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Pokazati da je analiza energetske efikasnosti
građevinskih objekata i brža i jeftinija korišćenjem
trodimenzionalne metode konačnih elemenata
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To show that analysis of the energy efficiency of the civil
facilities is faster and cheaper by the use of
threedimensional finite element method
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ORIGINALNOST ISTRAŽIVANJA
ORIGINALITY OF THE RESEARCH
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Upotreba originalnog in-house softvera “FEMIX” baziranog
na mešovitoj metodi konačnih elemenata, a koji je
potupno integrisan u pre i post processing komercialnog
koda “Straus7”
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The use of the original in-house software “FEMIX” based
on the mixed finite element method, which is fully
integrated in the pre and post-processing of the
commercial code “Straus7”
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KLJUČNE REČI - KEYWORDS
omotač zgrade
 nehomogeni zid
 prenos toplote
 matematički model
 numerička simulacija
 energetska efikasnost
 metoda-konačnih
elemenata
 KGH sistem
 CAD, CAE
 U-vrednost
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building envelope
non-homogenous wall
heat transfer
mathematical model
numerical simulation
energy efficiency
finite element method
CAD, CAE
HVAC
U-value
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LITERATURA - REFERENCES
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Hellen T. How to Use Elements Effectively. NAFEMS Ltd – he International Association for
Engineering Analysis Community, http://www.nafems.org, 2002
G+DComputing, “Straus7”, Finite element analysis system software package, Australia
http://www.strand.aust.com
Mijuca D. On hexahedral finite element HC8/27 in elasticity, Computational Mechanics, 33
(2004), 6, pp 466-480
Mijuca D, Žiberna A, Medjo B. A New multifield finite element method in steady state heat
analysis. Thermal Science, 2004; accepted for publishing
Todorović B, Projektovanje postrojenja za centralno grejanje, Mašinski fakultet Univerziteta
u Beogradu,1966
Todorović M, Živković B. Prednosti numeričke simulacije termičkog ponašanja zgrade pri
projektovanju sistema za klimatizaciju, Zbornik radova Trideset drugog kongresa o grejanju,
hlađenju i klimatizaciji, Beograd, 2001
Balocco C, A simple model to study a ventilated facade energy performance. Energy and
Buildings, 34 (2002) pp. 469-475
Mijuca D, Gajic D, Vukobrat M. Three-dimensional finite element method in energetic
efficiency of buildings” Termotehnika, accepted for publication (in Serbian)
CEN. 1996. Building components and building elements - Thermal resistance and thermal
transmittance - Calculation method. European Committee for Standardization, rue de
Stassart 36, B-1050 Brussels, Belgium. Ref. No. EN ISO 6946:1996.
Bazjanac V. Building energy performance simulation as part of interoperable software
environments, Building and Environment, 39 (2004), 8, pp. 879-883
CEN. 1995. Thermal bridges in building construction - Heat fows and surface temperatures
- Part1: General calculation methods. European Committee for Standardization, rue de
Stassart 36, B-1050 Brussels, Belgium. Ref. No. EN ISO 10211-1
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METODA KONAČNIH ELEMENATA
FINITE ELEMENT METHOD
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3-D metoda konačnih elemenata koristi se za analizu
stacionarnog problema prostiranja toplote kroz
nehomogeni omotač zgrade
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3-D finite element method is used for the analysis of
the steady-state building inhomogeneous envelope
heat transfer
Please note that present research is now standard in the
developed countries !!!
Therefore in this presentation - nothing is new or before time,
except the use of original mixed FE approach!
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METODA KONAČNIH ELEMENATA
FINITE ELEMENT METHOD
KT  F
2 FEA
methods
Primal approach
Software package Straus7
 A vv

 Bvv
BvvT  qv  
Fp 
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    F 
Dvv  Tv  
 p

Mixed approach
Original in-house software FEMIX
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SAVREMENO PROJEKTOVANJE ZGRADA
STATE OF THE ART IN THE BUILDING DESIGN
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Proračun temperature i toplotnog fluksa kroz zidove,
prozore i krovove zgrada je prvi korak proceni u
energetske efikasnosti zgrade, kao i u preventivi
problema koji nastaju usled termalnih napona i
kondenzacije.
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The calculation of temperature and heat flow through
the walls, windows and roof of a building is the first
step in estimates of energy efficiency of buildings, as
well as in preventing problems arising from thermal
stresses and condensation.
[1] Canadian Building Digest – 52: Heat Transfer at Building Surfaces
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Numerical examples
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Heat flow through inhomogeneous wall
Investigation of dependence of heat transfer coefficient (U–value)
on the material properties of wall components.
[2] CEN. 1996. Building components and building elements - Thermal resistance and thermal
transmittance - Calculation method. European Committee for Standardization, Ref. No. EN ISO
6946:1996.
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Heat flow through a corner
To determine heat losses throughout the structures.
[3] CEN. 1995. Thermal bridges in building construction - Heat fows and surface temperatures Part1: General calculation methods. European Committee for Standardization, Ref. No. EN ISO
10211-1
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Four storey building
To investigate change of heat losses if the thermally efficient
materials are used – the thermalvision camera effects
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Heat flow through inhomogeneous wall
geometry
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The inhomogeneous wall build of light expanded clay aggregate
block filled with polystyrene, mortar, with or without mineral wool is
considered.
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Heat flow through inhomogeneous wall
numerical results and convergence
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Heat flow through inhomogeneous wall
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Heat flow through inhomogeneous wall
Without mineral wool strip
With mineral wool strip
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Heat flow through inhomogeneous wall
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Heat flow through a corner
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This example deals with heat flow through a corner
and a single floor.
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Heat flow through a corner
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Heat flow through a corner
Temperature “Straus7”
Temperature “FEMIX”
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Heat flow through a corner
Heat Flux “Straus7”
Heat Flux “FEMIX”
From the results obtained, we may see that with a
computationally inexpensive mesh (7 sec) we successfully
meet the target results.
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Heat flow through a corner
animation
Heat Flux “Straus7”
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Four-storey building
thermalvision camera like effects
By the use of different material on the the last two floors
of building’s envelope energetic efficiency is increased
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Conclusion
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Described FEA methods are cheaper, more efficient and
precise, in regard to standard “hand-out” calculating
methods.
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It gives wide opportunities in the design process of the
buildings and prediction of its thermal behavior.
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The three-dimensional visualization of the calculated
temperature and heat flux fields is provided.
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Optimization of the cost/energy efficiency rate is enabled
in the design process of the building’s envelope and HVAC
system.
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CONTACT
Dr. Dubravka Mijuca
Faculty of Mathematics
Department of Mechanics
University of Belgrade
Studentski trg 16
11000 Belgrade
P.O.Box 550
Serbia and Montenegro
QUESTIONS
Phone 064-15-12-780
www.matf.bg.ac.yu/~dmijuca
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