progress and challenges in achieving high...
TRANSCRIPT
PROGRESS AND CHALLENGES
IN ACHIEVING HIGH
PERFORMANCE BUILDING
ENVELOPESProf. A. Janssens
DEPARTMENT ARCHITECTURE AND URBAN PLANNINGRESEARCH GROUP BUILDING PHYSICS, CONSTRUCTION AND SERVICES
OVERVIEW
Actual versus theoretical energy performance
Transmission heat loss calculation
Quality of the works
Performance assessment based on in-situ
measurements
Role of dynamic analysis methods
Epilogue: what about performance of building
services?
STRENGTHENING REQUIREMENTS IN ENERGY PERFORMANCE LEGISLATION
Towards nearly zero
energy houses in 2021:
• Very low energy use
for heating and
cooling:‒ Thermal insulation
‒ Airtightness
‒ Energy efficient ventilation
‒ Solar shading
• On-site or nearby
renewable energy
production
E-level, Flanders, Belgium
THERMAL INSULATION OF BUILDING ENVELOPE: EVOLUTION OF LEGAL REQUIREMENTS IN FLANDERS
0,24 W/m²K
= 0,040 W/mK
ACTUAL VERSUS THEORETICAL GAS CONSUMPTION IN BUILDING STOCK
Majcen, 2016
~200 000 cases EPC label database Netherlands 2010
Energy efficiency measures have smaller impact in reality
than according to EPC-rating
REASONS FOR DEVIATION BETWEENTHEORETICAL ENERGY PERFORMANCE AND REALITY
Model simplifications (quasi-steady state method)
Single zone calculation
Standardised user behaviour
Not all relevant phenomena considered
Incorrect input data
Not in line with normative procedures
Not corresponding to as-built situation
Poor quality of the works
DATA BASED ON AS-BUILT CHARACTERISTICS?
Carrié 2016, Qualicheck booklet
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Flatgebouw Rijwoning Halfopen Vrijstaand Bungalow
To
en
am
e K
-pe
il
Business as usual Standaard-details Koudebrugarm
RELEVANT PHENOMENA FOR CALCULATINGTRANSMISSION HEAT LOSS
2D- and 3D-heat transfer at building junctions and building
envelope structure (frame, ties,…) Relative share increases with better insulation
Importance of qualitative architectural detailing: Consistent avoidance of thermal bridges
Need for performance based rules and correct estimation
20%
10%
5%
K40
)2C(A
L300K
T
e
Multifamily Terraced Semi-detached Detached
Janssens et al. 2007, Buildings X
Incre
ase in K
-level
K
RULE 1Minimal contact length insulation
layers
EPB - accepted junction
Fulfils one of the
BASIC RULESFulfils
Ψe Ψe,lim
RULE 2Insertion of insulating element
RULE 3Long path of
minimal thermal resistance
and/or
INFLUENCE OF DESIGN AND WORKMANSHIP ON THERMAL TRANSMITTANCE: PITCHED ROOFS
Wood frame roof Underlay film with
unsealed overlaps
Janssens et al. 2007, Energy and Buildings
INFLUENCE OF WORKMANSHIP ON THERMAL TRANSMITTANCE: CAVITY WALLS
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SPOUWMUREN
U-W
AA
RD
E (
W/m
2.K
)
MW +LEK XPS +LEK XPS-VENT +LEK
Hens et al. 2007, J. Building Physics
APPROACHES TO BETTERQUALITY OF THE WORKS
Carrié 2016, Qualicheck booklet
New cavity walls:
• Improved training of contractors
• Improved systems and execution
sequence allowing inspection
Existing cavity walls: guaranteeing
quality of installing insulation in UK
• Mass market application
• Robust Consumer Protection Arrangements– Tested certified Systems– Enforcement of technical
guidance– 1st, 2nd and 3rd party
surveillance of work– Guarantee to create
confidence in the technology
• Government policies to create demand and provide correct signals
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1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
An
nu
al In
stal
lati
on
s
CWI Retrofit Trends
EE C 2 C E R T ExtE E S o P EE C 1
Forecast
(G. Miller 2012)
OVERVIEW
Actual versus theoretical energy performance
Performance assessment based on in-situ
measurements
Role of dynamic analysis methods
Epilogue: what about performance of building
services?
ASSESSMENT OF ACTUAL ENERGY PERFORMANCE OF BUILDINGS
Priority research theme IEA-EBC programme
IEA-EBC Annex 58: Reliable building energy
performance characterisation based on full scale
dynamic measurements, 2011-2015
IEA-EBC Annex 71: Building energy performance
assessment based on in-situ measurements,
2016-2020
Support the development of characterisation and
quality assurance methodologies to assess the actual
energy performance of buildings
IEA-ANNEX 58: BUILDING ENVELOPE TEST METHODS
Disadvantages of steady-state analysis methods:
long test durations, large uncertainties
U-value of building
components based on
heat flux meters
Heat loss coefficient of
whole buildings based
on co-heating tests
Energy model
characterization of
whole buildings based
on energy monitoring
N
1kk,s,i
N
1kk,s,ok,s,i
stos,N
q
TT
R
solsolvetrH IAT·HH
QUALICHECK FIELD STUDY 26 HOUSES WITH RETROFIT CAVITY WALL INSULATION
• Goal of the study:
assess effectiveness
of quality control
framework for cavity
wall insulation
• In none of the cases
the measured U-value
was significantly
higher than the
theoretical value
• Wide confidence
interval (10%)
Janssens et al. 2016,
Bauphysik
IEA ANNEX 58: GUIDELINES FOR APPLYINGDYNAMIC ANALYSIS METHODS
Dynamic analysis of heat
flux measuring data Dynamic test conditions
System identification‒ RC-models
‒ FDE or SDE
‒ Software tools
Advantages Shorter test duration
Dynamic performance
Error estimation
Hot climates
Concerns Advanced methods
Physical meaning of parameters 32232121
22 H·TTH·TT
dt
dT·C
Measured electric power and HFS Tiles power
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28-oct 29-oct 30-oct 31-oct 1-nov 2-nov 3-nov 4-nov 5-nov
Time [h]
Po
we
r [W
]
HFS Tiles
Electric
IEA ANNEX 71
Towards non-intrusive
testing:
• Smart meter readings
(short time span)
• Data driven modelling
• Estimate model
parameters
• Characterise heat
loss coefficient
eaie RR
1H
[179.0, 191.2] W/K
Bacher et al. 2011,
Energy and Buildings
Development and improvement of Software Tools
Updated versions of CTSM-R. Grey-box modeling. www.ctsm.info
Updated description on the DYNASTEE Web-pages
http://www.just-pm.eu/dynastee/data-analysis/software-tools/ctsm-r/
Common Exercises
FROM simple homogeneous opaque walls TO FULL SIZE BUILDINGS
ADVANCES IN DYNAMIC DATA ANALYSIS AND PERFORMANCE CHARACTERISATION
IEA-Annex 58
CONCLUSIONS
Environmental challenges require very high building
envelope performances
Reduce performance gap by correct calculation of
transmission heat loss and good quality of insulation
works
On-site testing is important to solve deviations between
calculated and real energy performance Applications in model development, ‘as built’ compliance
testing, commissioning,…
Data analysis methods Focus on dynamic analysis methods
‒ Shorter test duration
‒ More complete characterisation of energy performance
‒ Error estimation
Large potential, subject to further research
OVERVIEW
Actual versus theoretical energy performance
Performance assessment based on in-situ
measurements
Epilogue: what about performance of building
services?
RESULTS OF ECO-LIFE DEMONSTRATIONPROJECT: CARBON NEUTRAL DISTRICT
Energy efficiency targets:
New buildings: passive house
standard
‒ 15 kWh/m²/y heating demand
‒ Solar shading
Renovation: 50% better
compared to regulations
‒ 35 kWh/m²/y heating demand
Renewable energy production:
District heating
‒ 1MW wood chip boiler
‒ µWKK (bio-oil)
‒ Back-up gas boiler
PV-panels
YEARLY PRIMARY ENERGY BALANCE
Monitored energy use higher than expected: High network heat losses in district and collective heating networks
Low production efficiencies
Higher energy demand for space heating in some demonstration buildings
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