SEVENTH FRAMEWORK PROGRAMME SME - Targeted Collaborative Project EFFESUS SYMPOSIUM ENERGY EFFICIENCY FOR EU HISTORIC DISTRICTS SUSTAINABILITY DEVELOPMENT OF CONSERVATION COMPATIBLE REPLICABLE TECHNOLOGIES FOR ENVELOPE RETROFITTING OF HISTORIC BUILDINGS SVILUPPO DI TECNOLOGIE REPLICABILI E COMPATIBILI CON LA CONSERVAZIONE PER LA RISTRUTTURAZIONE DELL INVOLUCRO DEGLI EDIFICI STORICI Alexandra Troi April 8 th, 2016 Salone del Restauro, Ferrara, Italy
Retrofitting building envelopes Like in most existing buildings, also in historic buildings the envelope is crucial for their energy performance: walls are often thick, but they nevertheless conduct heat very well single glazed windows lead to very low surface temperature and are moreover not air tight at all.... Criteria to select the appropriate retrofit measures go beyond the potential increase in energy performance include also the reversibility of the intervention, possibility to conserve original material, and finally yet importantly, the aesthetic impact
Historic urban district Significant grouping of old buildings, built before 1945 and representative of the period of their construction or history Visby, Sweden, is an EFFESUS case study city Buildings do not necessarily have to be protected by heritage legislation.
Building conservation Conservation is the management of historic building in ways which do not damage their significance. The best protection for historic buildings is often continued use. Conservation is not about preventing change per se, but about preventing change that damages significance. Conservation is based on the following principles: retain appearance of building fabric, where significant retain materiality of building fabric, where significant prevent deterioration of building fabric, or at least decelerate it ensure reversibility of any interventions or treatment
EFFESUS innovations for envelope retrofitting Insulating lime mortar for use externally as render and internally as plaster Aerogel cavity-fill insulation insulating fibres for injection in cavities behind internal wall finishes Radiant selective coating for use on external surface to absorb and/or reflect heat radiation Upgrading historic windows with measures ranging from shades and adhesive films over multilayered glazing to a supply air window
Insulating lime mortar Lead partner Development aim lime-based mortar for internal and external use generally suitable for substrates found in historic construction: porous permeable to moisture low elastic modulus accommodates small-scale movement compares to existing insulating mortars better thermal performance λ-value < 0.08 W/(m K) not more costly
Insulating lime mortar Initial research Binder natural hydraulic limes (NHL) are generally used in building conservation NHL 5 achieves good strength development to bind a high ratio of an insulating filler Insulating fillers mineral granulates λ-value no better than 0.08 W/(m K) aerogel particles too fragile for mixing and to resist impact damage cork λ-value no better than 0.1 W/(m K) expanded polystyrene (EPS) good, proven thermal performance, stable beads, variety of sizes
Insulating lime mortar Product development Material high vol. % EPS filler additional additives Application hand- or spray applied needs finishing lime mortar coat needs preparation lime mortar coat where substrates cannot be cleaned sufficiently Practicalities drying time of 7 days, due to substantial thickness no additional costs compared to conventional mortar
Insulating lime mortar 80 heat/rain cycles (6h each): at least 48 hours drying with closed doors. 5 heat/cold cycles (24h each) 7 days curing afterwards pull-off tests
Insulating lime mortar EOTA wall durability test Testing preparation
Insulating lime mortar EOTA wall testing 80 heat/rain cycles (6h each): at least 48 hours drying with closed doors. 5 heat/cold cycles (24h each) 7 days curing afterwards pull-off tests
Insulating lime mortar Testing equipment
Insulating lime mortar Moisture measurement results Christmas holidays, test interrupted
Insulating lime mortar Product performance Thermal performance λ-value 0.0683 W/(m K) Density 0.3 kg/litre Strength after 90 days of curing Compressive strength 0.28 N/mm 2 Flexural strength 0.22 N/mm 2 Case study Benediktbeuern, Germany Testing of the new insulating line mortar as render on historic stone masonry
Aerogel cavity-fill insulation Lead partner Development aim aerogel insulation to fill cavities behind existing wall finishes historical lime plaster on timber laths retrofit plasterboard dry-lining compares to conventional cavity-fill insulation better thermal performance λ-value > 0.035 W/(m K) not much more costly
Aerogel cavity-fill insulation Product development from monolithic aerogel fragile aerogel granulate, requiring stabilisation thermal resistance to be outstandingly high high costly and energy-intensive in production from aerogel blanket insulation polystyrene mesh fabric, impregnated with aerogel made from new, recycled or waste aerogel blankets thermal resistance better than conventional cavityfill insulation low cost if made from recycled or waste material
Aerogel cavity-fill insulation Material delivered for testing
Aerogel cavity-fill insulation Equipment used for injection of material
Aerogel cavity-fill insulation Material in test box for conductivity measurement
Aerogel cavity-fill insulation Thermal conductivity of fibres as delivered and after injection
Aerogel cavity-fill insulation Full Scale Mock-Up for Test in Hot Box 1 2
Aerogel cavity-fill insulation Full Scale Mock-Up for Test in Hot Box 1 2
Aerogel cavity-fill insulation Full Scale Mock-Up - Test in Hot Box
Aerogel cavity-fill insulation Full Scale Mock-Up - Test in Hot Box Results of the test HFM 1 HFM 2 without Name Unit Definition original aerogel with with aerogel aerogel post Tse C Outside face temperature under the heat flux meter -9.77-9.83-9.73 Tsi C Inside face temperatures under the heat flux meter 10.95 15.67 17.57 q W/m 2 Density of the heat flow rate -30.64-11.2-11.08 Rt m 2 K/W Sample thermal resistance 0.68 ± 3.4% 2.28 ± 2.8% 2.46 ± 2.6% Rsi m 2 K/W Inside surface thermal resistance 0.13 0.13 0.13 Rse m 2 K/W Outside surface thermal resistance 0.04 0.04 0.04 RT m 2 K/W Total thermal resistance 0.85 2.45 2.63 U W/m 2 K Total thermal transmittance 1.18 0.41 0.38 l calculation of the aerogel from the measured Resistances 0.023-0.025 W/mK
Aerogel cavity-fill insulation Product performance Thermal performance λ-value down to 0.025 W/(m K) Moisture performance vapour permeable highly hygrophobic Practical issues Loose fill should be reversible Dusting during handling health issue Case study Glasgow, United Kingdom Testing of fibrous aerogel cavity-fill insulation, installed behind various internal wall finishes
Radiant selective coating Lead partner Development aim coating for external surface application to reduce heat transfer by both conduction and radiation intended for Mediterranean climates minimal visual impact cost effective
Radiant selective coating Coatings and test substrates Ca Si C Al Fe Mg coating 1 X coating 2 X Istanbul stone X Villamayor sandstone X X Markina limestone X clay brick X X X X X lime mortar X
Radiant selective coating Reversibility issues Neither of the radiant selective coatings is reversible on its own I. Tylose MH Reversible primer is required to separate coating from substrate I. Methylcellulose Tylose MH 300 P2 plasma-consistency substance II. Paraloid B-72 thermoplastic resin II. Paraloid
Radiant selective coating Removal assessment When used with Methylcellulose primer, none of the coatings is fully removable, regardless of the substrates tested When used with Paraloid primer, coating 1 is removable from calcium stones, but not fully removable from silica stones coating 2 is not fully removable regardless of substrate tested
Radiant selective coating Performance assessment
Radiant selective coating Performance assessment
Radiant selective coating Performance assessment
Radiant selective coating Whole year building performance dynamic simulation Hypotheses: The coating will reduce surface temperature The coating will improve the energy performance reduce the cooling load or avoiding a cooling need while keeping acceptable indoor comfort Under which conditions is this true? We looked at historic walls, i.e. high thermal mass, rather high lambda but for comparison also at insulated and/or light weight constructions Different orientation Different climates: Sevilla, Istanbul, Different internal loads and ventilation strategies
Radiant selective coating Dynamic simulation of building performance One clear benefit: reduction of surface temperature For Istanbul climate average daily temperature cycles: 20 K 10 K high daily maxima: 40 C 30 C For Sevilla climate average daily temperature cycles: 25 K 12 K high daily maxima: 50 C 35 C
Radiant selective coating Dynamic simulation of building performance Improved energy performance more difficult to generalize: Here we have to consider the whole year performance. What is positive in summer is perhaps not desirable in winter? Sevilla climate cooling demand 67.4 60 kwh/m² heating demand is anyway too small to matter Istanbul climate cooling demand 42.8 37.5 kwh/m² ( -5.3) heating demand 13.2 15.8 kwh/m² (+2.6)
Radiant selective coating Performance testing continues including testing of water absorption by capillary action material durability installation practicalities reversibility in practice Case study in Istanbul, Turkey Testing of radiant reflective coatings, applied to various historical substrates
Upgrading historic windows Lead partner Windows are an integral part of the architecture of a building preserving them is critical to its heritage value They are at the same time decisive both for comfortable indoor environment energy performance of a building
Upgrading historic windows Development aim Propose window upgrade solutions which reduce window environmental impact do not reduce the heritage value can be selected and combined to fit the specific at the single building
Upgrading historic windows Approach Example window: Box type double sash window Numerical modelling & lab tests Performance criteria U-value thermal performance G-value solar energy transmittance Visual transmittance Lowest Temperature Moisture performance
Upgrading historic windows Prototype 0 Original Window box-type window two layers of sashes separated by a 12 cm wide air gap Already a big leap forward in thermal comfort and insulation compared to single glazing! Many different varieties of such windows exists, characteristic of the country or region and in some cases even for the decade of the building s construction. P0 original window U-value measured 2.47 [W/m²K] calculated 2.46 G-value calculated 0.78 T vis calculated 0.81 T lowest measured 10.71 [ C] calculated 11.03
Upgrading historic windows Prototype 1 Thermal shades P1 P0 original Cellular shades (type: cell in cell) add thermal resistance to the window and reduces solar heat gain in the summer. Installed in the gap between glasses U-value measured 1.92 2.47 [W/m²K] calculated 0.99 2.46 G-value calculated 0.58 0.78 T vis calculated 0.54 0.81 T lowest measured 11.48 10.71 [ C] calculated 16.6 11.03
Upgrading historic windows Prototype 2 Adhesive low-emissivity films Adhesive plastic films with low emissivity properties can be added to the existing glass (low-e coatings can only be applied during the manufacturing process) P2 P0 original U-value measured 2.37 2.47 [W/m²K] calculated 2.07 2.46 G-value calculated 0.47 0.78 T vis calculated 0.63 0.81 T lowest measured 10.85 10.71 [ C] calculated 12.23 11.03
Upgrading historic windows Prototype 3 Multi-layered glazing Ultra-thin glass (from 0.1) as middle panes in a multi-layered glazed unit. high insulation levels lightweight and narrow Allows to preserve the original design of the historic window (and frame)! P2 P0 original U-value measured - 2.47 [W/m²K] calculated 1.26 2.46 G-value calculated 0.67 0.78 T vis calculated 0.70 0.81 T lowest measured - 10.71 [ C] calculated 15.4 11.03
Upgrading historic windows Prototype 4 Air Sandwhich 5 thin transparent plastic layers glued to the original panes Increased thermal resistance due to multiple air gaps, adding each conductive resistance of air (limited convection due to limited width of the gap). multiple layers, reducing radiation heat exchange P4 P0 original U-value measured 1.84 2.47 [W/m²K] calculated 1.55 2.46 G-value calculated 0.49 0.78 T vis calculated 0.57 0.81 T lowest measured 12.39 10.71 [ C] calculated 14.7 11.03
Upgrading historic windows Prototype 5 Supply Air Window valves allow fresh air to flow from outside through the gap between two panes to the room recovering heat that is flowing through the glass towards the outside fresh incoming air is heated during its passage by convection and conduction If the window happens to receive direct solar radiation it also acts as an air solar collector, but this is not its primary operating mode The thermal performance P5 P0 of original the supply air window was not simulated U-value measured 2.47* 2.47 Primary [W/m²K] benefit calculated of supply 2.46 2.46 air windows is to improve air G-value calculated 0.78 0.78 quality and recover heating energy. T vis calculated 0.81 0.81 T lowest measured 10.71 10.71 [ C] calculated 11.03 11.03
Upgrading historic windows Combination of measures P1+P2 Shading + adh. film P1+P3 Shading + multi-glazing P3+P4 multi-glazing + air sandwhich P0 original U-value measured - - - 2.47 [W/m²K] calculated 0.79 0.79 1.11 2.46 G-value calculated 0.41 0.49 0.44 0.78 T vis calculated 0.5 0.46 0.53 0.81 T lowest measured - - - 10.71 [ C] calculated 17.2 17.3 16.2 11.03
Upgrading historic windows Product performance P3 has the lowest thermal transmittance possibly changes to original window structure and is labour & cost intensive. P4 easy to install, some thermal improvement visual appearance maybe unacceptable P1 & P2 easy to install & some thermal improvements (shade may also reduce glare!) may have unacceptable visual impacts. All of these strategies can be enhanced with supply air window valves. Case study Budapest, Hungary Windows with improved insulation (together with ventilation and intelligent indoor climate solutions)
Insulating lime mortar Aerogel insulation Radiant coatings Window upgrade Product testing Product installations
This presentation reflects only the author s view, and the European Union is not liable for any use that may be made of the information contained. EFFESUS innovations for envelope retrofitting of historic buildings Ferrara, 8 April 2016 Thank you for listening www.effesus.eu Alexandra Troi Alexandra.troi@eurac.edu The EFFESUS project has received funding from the European Union s Seventh Framework Programme for research, technological development and demonstration through grant agreement no. 314678.