Roberto Lollini Coordinatore gruppo “Energy Management in Buildings”, EURAC Istituto per le Energie Rinnovabili. La sua attività è attualmente focalizzata sull’analisi del complesso edificio-impianto al fine di valutare il bilancio energetico e il comfort determinato da diverse soluzioni progettuali, sia su edifici nuovi che esistenti. Si occupa di pianificazione e gestione di progetti di ricerca nel settore della fisica delle costruzioni, in particolare per soluzioni passive.

1. TIS innovation park
Questioni di facciata | Alles Fassade
Innovazione, flessibilità e multifunzionalità | Innovation, Flexibilität und
Multifunktionalität
R. Lollini – Sistemi di facciata per il retrofit di edifici
Fiera di Bolzano | Messe Bozen, Sala Latemar | Latermarsaal 06.03.2015
Workshop

2. Façade retrofitting
depending on climate challenge, context and building loads:
- specific features
- consistency with architectural concept
- integration with energy systems (and the energy grids)
- multi-functions
target:
- high impact on building system: energy, power, comfort
- low investment and LCC
Robust, flexible, easy functioning, low investment, low maintenance,
replicable solutions to minimize building energy needs, impact on the
energy grids and environment, while keeping high IEQ level, by
exploiting local natural sources through thermal, moisture, ventilation,
light control

3. Façade retrofitting goals
General goals
 Restore/improve the building functionalities
 Building code and standard conformity
 Construction product requirements
Specific retrofitting goals and/or possible synergies (examples):
 Rehabilitation and/or creation of internal/external spaces
 To solve safety and hygienic issues
 To improve comfort (localised and diffuse)
 To reduce operation costs (energy, maintenance, …)
 To manage security problems
 …

4. Structural risks/damages: e.g. thermal bridge causing condensation and corrosion
Moisture flux
condensation
 risk of corrosion
Source: Gerald Gaigg et al. , University Innsbruck Institut für Konstruktion und Materialwissenschaften
Arbeitsbereich energieeffizientes Bauen
Façade retrofitting goals

5. Thermal losses: e.g. hot piping losses
Source: Gerald Gaigg et al. , University Innsbruck Institut für Konstruktion und Materialwissenschaften
Arbeitsbereich energieeffizientes Bauen
Façade retrofitting goals

6. Hygienic rehabilitation: mould growth due to humidity in wall and thermal bridges
Source: www.berik-schnabl.de/assets/images/autogen/a_Schimmel.jpg
Façade retrofitting goals

7. Thermal discomfort : e.g. Tmr, radiant asymmetry (walls/windows)
ROOM
Longer wall2: :
7.5 m
Longer wall1:
7.5 m
Shorterwall2:
5m
Shorterwall1:
5m
Façade retrofitting goals
Close to wall1 Central position Close to wall2
Tmr minor axis Tmr major axis
Ugl = 5 W/m²K, Toutdoor = 0°C and Tindoor=20°C, No solar radiation  Tsi_gl = 12°C

8. High energy related costs: energy demand trends per age
Source: Zimmerman, ECBCS Annex 50
Façade retrofitting goals

9. Envelope functions
Façade is itself already a building «multifunctional element»
 How to properly design a multifunctional element for retrofitting?
Italian historic building, Split units’
condensators. Source: lavorincasa.it

10. FUNCTIONS
CONTROL HEAT LOSSES
TRANSFORM ENERGY
HEATING AND
COOLING
AIR INLET HANDLING AND
AIR OUTLET HEAT
RECOVERY
BUILDING
SERVICES/SYSTEMS
SELECT AND CONTROL
SOLAR GAINS
Envelope functions
Responsive while exploiting climate potential

11. Non conventional retrofit on envelope
How deep is the retrofit intervention to reduce energy needs?
After a deep retrofit the buildings consume 60-90% less primary energy
compared to the status of the existing buildings1.
1 M. Economidou, “Europe’s buildings under the microscope”, 2011
- Turn balconies in loggias
- Basement insulation
- Rear ventilated facades
- Natural ventilation/Passive cooling
strategies
- Green facades and roofs
- Interaction Facade-Building
- Prefabricated Multifunctional Facades
SYSTEMS and APPLICATIONS MATERIALS
ENVELOPE COMPONENTS
- Phase Change Materials
- Super-insulating materials
- Low-e and reflective
coatings
- Mechanical ventilation
with heat recovery
- Air Handling Unit
- Complex shading systems
- Solar facade (PV, ST)

12. Which retrofit action is more suited? Technical and economic feasibility
LOCATION QUALITY RETROFIT POTENTIAL
POTENTIAL FOR +ENERGY POTENTIAL FOR PREFABRICATION
Retrofitting potential analysis

13. Which retrofit action is more suited? Technical and economic feasibility
- Infrastructure and mobility
- Pollution
- Available area
- Ground properties
- Thermal insulation degree
- Geometric characteristics
- Housing demand in the
district
LOCATION QUALITY
- Densification
- Façade static conditions
- Thermal envelope
- Danger associated to materials
- Accessibility
- Plant system conditions
- Energy demand
- Regulation constraints
RETROFIT POTENTIAL
- Solar energy exploitation
- Energy demand covered by RES
- Power grid connections
- District heating connections (if any)
POTENTIAL FOR +ENERGY
- Material delivery and assembly
- Presence and position of
balconies
- Kind of openings (windows,
doors)
- Roof typology and installations
POTENTIAL FOR PREFABRICATION
Retrofitting potential analysis

14.  BIST, Building Integrated Solar Thermal;
 BIPV, Building Integrated Photo Voltaic;
 Prefabricated Multifunctional Facade Systems;
 ETICS (External Thermal Insulation Composite System);
 BI Ventilation;
 BI Lighting Control;
 Coatings.
Façade retrofitting technologies

15. Main features:
- Suited for facade glazing systems in
aluminium, PVC or wood
- The solar collector is installed
mechanically as an ordinary single
pane of glass
- The absorber is treated with a
selective layer of thin film to make the
energy conversion more efficient
- Very high efficiency due to very low
heat losses
Cross section
Technology: Solar flat plate glazed collector
Source: S Solar
BIST Building Integrated Solar Thermal

16. Technology: BIPV
Main features:
- This material allows to recover the
investment cost
- It can allow daylight transmission
(depending on transparency)
- Thermal insulation
- Availability of different colours
- Availability of dummies elements
Colored PV Galss
PV second skin_GENyO BuildingPV curtain wall_Guadalhorce
BIPV_Opaque module
Source: ONYX Solar
BIPV Building Integrated Photo Voltaic

17. Source: http://www.gap-solutions.at/en/
Technology: Wooden prefabricated façade modules
Main features:
- Low impact on users
- High insulation properties
- Installation without scaffolding with
an easy and dry procedure
- On-site work time reduced (compared
to standard external thermal
insulation)
Prefab. Multi-functionale Façade Systems

18. Technology: External thermal insulating board (EPS)
Main features:
- Standard available panel thickness 54
mm (45 EPS insulation + 9 mortar),
66 mm (57+9) and 89 mm (80+9)
- Fiber-reinforced mortar as external
cladding
- Dry construction system (aluminium
transoms fixed to the wall)
Source: PIZ cladding system
External Thermal Insulation Systems

19. Technology: Window integrated decentralized ventilation system
Main features:
- Air flow from 15 to 75 m³/h
- It can be installed in all types of windows
(PVC, aluminium and wood)
Technology: Wall integrated decentralized ventilation system
Main features:
- No pipes are needed respect to centralized systems (no distribution
network)
- More suited for retrofit scenario (usually there‘s no place for a
distribution plant)
- Heat recovery efficiency: from 73% to 88%
- Air flow from up to 100 m³/h
Source: Airria
BI-V Building Integrated Ventilation
Source: Meltem

20. Technology: Window chain actuators for natural ventilation
Main features:
‐ 50-550 mm in increments of 10 mm
‐ Opening speed: programmable from 3 to 9.5
mm/s
‐ To be used with top-hung, bottom-hung and
turning windows
Source: Master WiCloud
BI-V Building Integrated Ventilation

21. Technology: Prefabricated monoblock system
Main features:
- High invasivity in removing the old window
and frame and window box and applying the
new system
- Thermal bridges resolution
- Lamellae system can be studied to avoid glare
but ensure outdoor visibility
Source: Hella
BI-LC Building Integrated Lighting Control

22. Technology: Heat reflective coatings
Main features:
‐ High solar reflectance and high emittance in
the thermal infrared region
‐ It supports thermal insulation (not substitute)
‐ Protection against algae and dirt
‐ It can be applied both on external and internal
surface
Coatings

23. Tools and performance indicators
 Few cases and very specific real data of complex facade system
performance (reliability of commonly used design tool??!!)
 A systemic design tool doesn’t exist!  need to use several tools!
Interdisciplinary of design approaches and tools:
 energy use
 air movements
 lighting quality and quantity
 building operation
 acoustic
 condensation risk
 structural
 fire
 …
Design approaches and tools

24. Modelling and simulations
• Multi-objectives optimization (performed through in-house pieces of codes)
• Sensitivity analysis and model calibration (performed through in-house pieces
of codes)
• Black-box modelling (Matlab tool box)
• Coupling thermal simulation (e.g. EnergyPlus and Trnsys) with natural
ventilation (e.g. COMIS) and lighting (e.g. radiance)
• Dynamic analysis of critical points (e.g. Delphin)
• Building typologies in a stock analysis and definition od retrofitting scenarios
(e.g. CasaClima Pro PHPP)
• CFD for comfort analysis (e.g. Comsol and DesignBuilder)
• Climate potential for natural ventilation and ventilative cooling (in house tool)
Design approaches and tools

25. Tools to support designing of component integration
 Detailed modelling: e.g.
 FDM, FEM, FVM
 Optical and radiation models for complex fenestration systems
 «Ad hoc» developed models for non standard components
 Lab tests
 Guarded hot box (e.g. INTENT – Eurac)
 Outdoor labs (e.g. Passys/e-Lab)
 Material properties characterisation
Design approaches and tools

26. Impact on thermal zones and whole building
Single zone
 How does the component impact on the thermal zone
(transient and steady-state behaviour)
 Both detailed models (FDM, FEM, FVM) and simplified models
(RC network – concentrated parameters)
 Examples:
 COMFEN, Energy Plus, TRNSYS, ESP-r, Radiance,
AiflowNetwork, …
Whole building
 Simplified model (as seen before)
 Need to integrated new components! (e.g.: AL, DSF,) (Esp-r, Eplus, TRNSYS:
e.g. New models for daylighting, ventilated facades)
Design approaches and tools

27. INTENT Integrated Energy walls
Based on guarded hot-box (EN ISO 8990) for façade concept development +
performance characterization through simulations and experimental campaign
Testing facility for thermal-energy characterization of
passive and solar activated building envelope systems
• Surface temperature
assessment with sun
irradiation around
1000 W/m2
• Deformation
assessment
33
Testing facilities

28. The g-value measurement facility at RenEne INTENT lab
Testing facility for g-value measurement
g-value
Experimental arrangement for fenestration/shading/daylighting concept
development + performance characterization through simulations and experimental
campaign (standard under development ISO/WD 19467 nel ISO/TC 163/SC1)
34
Testing facilities

29. Testing facilities
e-Lab the envelope Lab
To test façade system under actual working conditions, emulating a built
environment with actual HVAC systems and surrounding energy grids
e-Lab as foreseen for the Technology Park area. Source: Eurac
Testing facility for multi-functional façade systems
performance assessment

30. Goals:
Envelope retrofit kit for office building retrofit:
• Curtain wall (metal-glass) replacement
• Integrated sorption collector delivering hot and
cold air for indoor air heating and cooling
Requirements:
• Simple layout for ..
• .. easiness of installation and maintenance
e.g. „facade integrated sorption collector“ in EU
FP7 Inspire
http://www.inspirefp7.eu
Eurac as coordinator

31. Design methodology:
• Sorption collector prototype and façade
requirements (air-tightness, water proof,
thermal break, uniformity of external
finishing, collector dimensions,…)
• Sorption collector design and first prototype
• Simulation (collector and building scale) and
testing
• Façade frame adaptation (holes for the
collector connection)
• Verification of critical nodes (air pressure
drops, thermal bridge, inlet air velocity,…)
• Iteration (optimized design, next simulation
and testing)
e.g. „facade integrated sorption collector“ in EU
FP7 Inspire
http://www.inspirefp7.eu
Eurac as coordinator

32. e.g. modular multifunctional climate adaptive
facade system in EU FP7 CommONEnergy
Optimization based on:
1. Glass system properties
2. Solar protection system (shadowing system)
3. Natural ventilation system (new openings)
http://www.commonenergyproject.eu/
Eurac as coordinator

33. The façade of the market was divided in
three different sections:
• upper section with skylight windows
(some of windows are open able)
• central section with glass structural
wall
• bottom section characterised by
windows and glazing system with
graphics to reproduce the original wall
design (no shadings was allowed in this
part).
The building is located in Central-South
Spain with temperatures <0 ̊C in winter
and during most part of the year, and hot
temperatures in summer over >30 ̊C.
e.g. modular multifunctional climate adaptive
facade system in EU FP7 CommONEnergy
http://www.commonenergyproject.eu/
Eurac as coordinator

34. Glass 1 [6+6/16/6+6] Glass 2 [6+6/16/8] Glass 3 [6+6/16/6+6]
6+6mm Solar Control /
16mm argon / 6+6mm
6+6mm Low-e / 16mm
argon / 8mm
6+6mm Low-e / 16mm
argon / 6+6mm
U Value
(W/m2K)
Solar Factor
(g)
U Value
(W/m2K)
Solar Factor
(g)
U Value
(W/m2K)
Solar Factor
(g)
1.0 0.27 1.1 0.60 1.1 0.56
e.g. modular multifunctional climate adaptive
facade system in EU FP7 CommONEnergy
http://www.commonenergyproject.eu/
Eurac as coordinator

35. During the early design stage
many suggestions were made
regarding a very efficient
daylight systems to prevent
glare, redirect light into the
depth, shade against sun and a
provide maximum visual
contact between inside and
outside.
A commercial system that can
be operated in the described
way is WAREMA E80 A2
(beaded slats)
e.g. modular multifunctional climate adaptive
facade system in EU FP7 CommONEnergy
http://www.commonenergyproject.eu/
Eurac as coordinator

36. The building shape has high
potential for exploiting stack
effect ventilation.
The definition of a ventilative
cooling strategy involves the
whole building envelope as
openings have to be located at
opposite sides and at different
height on the building
envelope.
e.g. modular multifunctional climate adaptive
facade system in EU FP7 CommONEnergy
http://www.commonenergyproject.eu/
Eurac as coordinator

37. -60,00
-50,00
-40,00
-30,00
-20,00
-10,00
0,00
10,00
ACC
Proposal 1
ACC
Proposal 2
ACC
Proposal 1 +
Shading
system
ACC
Proposal 2 +
Shading
system
ACC
Proposal 3 +
Shading
system
ACC
Proposal 4 +
Shading
system
ACC
Proposal 3 +
Shading
system +
Ventilation
system
ACC
Proposal 4 +
Shading
system +
Ventilation
system
%ofreduction
Heating
Cooling
Total
http://www.commonenergyproject.eu/
Eurac as coordinator
before after
e.g. modular multifunctional climate adaptive
facade system in EU FP7 CommONEnergy

38. Yearly insolation: a) Izmir blank, b) Izmir with background,
c) Bolzano blank, d) Bolzano with background
To evaluate yearly solar radiation on parametric
geometrical surface …
e.g. „methodological development of a BIPV
geodesic envelope“ in EU FP7 Solar Design
http://www.solar-design.eu
Eurac as partner

39. Threshold: 1300kWh/m2yr
Capacity: 3,1 kWpeak
Production: 3600kWh/yr
Price: 9300 €
Threshold: 900kWh/m2yr
Capacity: 7 kWpeak
Production:7000kWh/yr
Price: 21000 €
… and then to evaluate yearly PV production on
surface’s elements
A Threshold is a value of
insolation below which it´s
unpractical to place a pv
module.
http://www.solar-design.eu
Eurac as partner
e.g. „methodological development of a BIPV
geodesic envelope“ in EU FP7 Solar Design

40. Cash flow over time for Bolzano without background: the highest
earnings are for a:
• threshold: 1000 kWh/m2 yr
• capacity: 5.9 kWpeak
• production: 6200 kWh yr
e.g. „methodological development of a BIPV
geodesic envelope“ in EU FP7 Solar Design
http://www.solar-design.eu
Eurac as partner

41. Multifunctional façade concept:
• Metallic sub-structure
• Solar collector
• Insulation layer
• Radiant system in the outer side of the
existing wall (dynamic insulation)
• More performing windows
Case study_East view_Bolzano, via Palermo
Multifunctional facade module
including window:
Size: 4300x3000 mm
Weight: 100 kg/m²
Feasibility study – Bolzano, Italy
e.g. „concept of prefab multifunctional facade
module“ internally developped by Eurac

42. Thank you!
façade systems team
stefano.avesani@eurac.edu, alessio.passera@eurac.edu, roberto.lollini@eurac.edu
www.eurac.edu