Vertical Greenery Systems (VGS) for energy savings in buildings International Green Wall Conference 4-5 th September 2014 Stoke-on-Trent, UK Julià Coma Dr. Gabriel Pérez Dr. Cristian Solé Dr. Albert Castell Dr. Luisa F. Cabeza
Contents Introduction Objectives Previous research Current research Further research Conclusions Acknowledgements 2
Vertical Greenery Systems contribute positively to the improvement of the built environment: Aesthetics urban landscaping Support to biodiversity Noise reduction Energy savings Heat island reduction Etc. Introduction Pergola Building Thuir. France Belén, Costa Rica 3
Introduction The classification of VGS must be taken into account for energy savings purposes Extensive systems Intensive systems Traditional Green façades Double-skin Modular trellis Wired Mesh Perimeter flowerpots Living walls Panels Geotextile felt Pérez G. Façanes vegetades. Estudi del seu potencial com a sistema passiu d estalvi d energia, en clima mediterrani continental. PhD thesis. Universitat Politècnica de Catalunya, 2010 4
Introduction The main mechanisms of VGS as passive tool for energy savings are four: Shade effect: Interception of the solar radiation by the plants Cooling effect: Due to the transpiration from the plants Insulation effect: Air layer create in the foliage Wind barrier effect: Variation of the direct wind effect over the building façade by the plants and the support structure Shade effect seems to be the most influential 5
Difficulties to measure the influence of VGS on building thermal performance: Differences between constructive systems Living organisms (species, growth, diseases, etc) Different climate conditions Introduction Difficulties to quantify the effects individually Sihlcity Greenwall, Zurich 6
Objectives To study the use of VGS as passive tool for energy savings in Mediterranean continental climate To quantify the shadow effect To quantify the energy savings These studies are conducted in a large real scale installation that the research group GREA has in Puigverd de Lleida (Lleida, Spain). http://www.grea.udl.cat 7
Previous research Previous actions Action 1: Shadow capacity of different climber species. 2009-2010 Action 2: Thermal behavior of green facades in an existing experimental cubicle. 2010-2011 Action 1 Tª 3, HR 3 (z = 3m) Action 2 Radiació solar incident exterior Radiació solar incident paret Tª 1, HR 1 Exterior Tª 2, HR 2 (z = 1,5m) Tª 4, HR 4 Interior Pérez G. et al. Green vertical systems for buildings as passive systems for energy savings. Applied Energy 2011;88:4854-4859 Pérez G. et al. Behaviour of green façades in Mediterranean Continental climate. Energy Conversion and Management 2011;52:1861-1867 8
Transmisividad lumínica Previous research Action 1: Shadow capacity of different climber species. 2009-2010 The ability to intercept solar radiation of vegetation, even at low foliage densities, is similar to that offered by artificial barriers such as awnings, slats, etc. according to the Spanish technical code for buildings (CTE). 0,7 Artificial barrier shadow factor 0,6 Cantilever 0.16 0.82 Setback 0.17 0.82 Opaque awnings 0.02 0.43 Translucent awnings 0.22 0.63 Horizontal slats 0.26 0.49 Vertical slats 0.32 0.44 LUXOMETER 0,5 0,4 0,3 0,2 0,1 0,0 9 h 10 h 11 h 12 h 13 h 14 h 15 h 16 h 17 h Hora Viña virgen Madreselva Clematide Hiedra 9
Previous research Action 2: Thermal behaviour of green facades in an existing cubicle. 2010-2011 10
Previous research Action 2: Thermal behaviour of green facades in an existing cubicle. 2010-2011 The shadow effect is evident over the wall surface temperature, reaching 14 ºC less than in the reference cubicle with 50% of the surface covered Shade capacity (14 ºC) 11
Previous research Action 2: Thermal behaviour of green facades in an existing cubicle. 2010-2011 Shadow effect influences over indoor temperature too. The reduction was about 1 ºC less in the facade cubicle under free floating conditions Inside temperature reduction free floating (1ºC) 12
Energy [kwh] Previous research Action 2: Thermal behaviour of green facades in an existing cubicle. 2010-2011 Some energy savings was observed for the accumulated energy consumption under indoor controlled conditions (24 ºC) 12 10 8 6 4 2 0 07-07-11 08-07-11 09-07-11 10-07-11 11-07-11 12-07-11 Day Green facade Reference Accumulated energy consumption by the heat pumps. July 2011. Set-point 24 ºC 13
Current research Current research As the previous results were positive, a new green facade have been built, covering the east, south and west walls 14
Current research Current research Deciduous vegetation (Boston Ivy, Parthenocissus Tricuspidata) was planted in June 2012 and was growing during summer 2012 and spring 2013 15
Temperature (ºC) Current research Data from summer 2013 show the shade effect, with a set point of 24 ºC 50 45 40 35 30 25 20 15 10-7 0:00 10-7 6:00 10-7 12:00 10-7 18:00 11-7 0:00 South Green internal facade; wall South green internal facade wall Outside temperature South external wall reference roof Reference; South external wall Period 7ºC South Reference; internal South reference internal roof wall South external wall green facade Green facade; South external wall 16
Accumulated electrical energy consumption [kwh] Current research And interesting energy savings (set point 24 ºC), up to 50% 16 14 12 10 8 6 4 2 0 2-7 3-7 4-7 5-7 6-7 7-7 8-7 9-7 10-7 11-7 Reference roof Reference cubicle Energy Green façade green cubicle facade 17
Current research In 2014 a Green Wall was built (BuresInnova S.A.) on another identical cubicle Well adapted perennial bushes Helichrysum stoechas and Rosmarinus officinalis 18
Temperature [ºC] Current research Data from summer 2014 with a set point of 24 ºC. The shade effect was confirmed for the Green Wall too 50 45 40 12 ºC 17 ºC 35 30 25 20 15 10 15-7 0:00 15-7 6:00 15-7 12:00 15-7 18:00 16-7 0:00 Green Wall; South internal wall Period Green Facade; South internal wall Reference; South internal wall Outside temperature Green Wall; South external wall Green Facade; South external wall Reference; South external wall 19
Accumulated electrical energy consumption [kwh] Current research Data from summer 2014. Energy savings of more than 50 % 7 6 5 4 3 2 1 0 9-7 10-7 11-7 12-7 13-7 14-7 15-7 16-7 Period Green Wall Green Facade Reference 20
Further research In 2013 a review of the scientific literature available to date regarding to the use of VGS as passive tool for energy savings was conducted Pérez G. et al. Vertical Greenery Systems (VGS) for energy saving in buildings: a review. Renewable and Sustainable Energy Reviews (2014), pp. 139-165 Some of the most important conclusions which will guide future research are: The number of species used for Green Facades is very limited, mostly climbing plants, having two predominant species: Ivy (Hereda helix) Perennial Boston Ivy (Parthenocissus tricuspidata) Deciduous Chinese Wisteria (Wisteria sinensis) Deciduous For Green Walls the number of species used is higher, mostly herbaceous and bushes, but this can result in different thermal behaviours in the same Green Wall 21
Further research Most of the studies found are located in Europe (mainly Green Façades) and Asia (mainly Green Walls). 22
Further research A lack of studies in areas of the world that receive more radiation, in which these systems consequently could be more effective, have been observed 23
Further research The most interesting parameters to consider for energy savings purpose design of VGS are: Traditional Green Facades Double-skin Green Facades Green Walls Purpose/period Heating/Cooling/Both x x x Species used x x x Facade orientation x x x Foliage thickness (or coverage %) x x x Air gap thickness x x Substrate thickness and composition x 24
Conclusions Shade effect Vertical Greenery Systems (VGS) show a great shade effect with reductions in outside wall surface temperatures ranging from 7 ºC to 12 ºC, for Green Facades, and up to 17 ºC for Green Walls, for the studied constructive systems Energy savings This shade effect implies great energy savings around 50 %, in summer periods, for the studied constructive system, under Mediterranean Continental climate 25
Conclusions Further research To study the contribution of the different effects on energy savings To study the suitable plant species for energy savings purpose To develop these systems in areas of the world that receive more radiation To focus the research/design on the parameters/variables that regulate the thermal behavior of these systems: Purpose/period (heating/cooling) Species Orientation Foliage thickness - Air gap Substrate thickness and composition 26
Acknowledgements To the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement n PIRSES-GA-2013-610692 (INNOSTORAGE) To the Spanish government (ENE2011-28269-C03-01, ENE2011-28269-C03-02, ENE2011-28269-C03-03 and ULLE10-4E-1305) To the Catalan Government for the quality accreditation given to their research group (2014 SGR 123) To Department of Vegetal Production, University of Almería (Almería), the company Buresinnova S.A (Barcelona) and with the City Hall of Puigverd de Lleida Julià Coma wants to thank the Departament d'universitats, Recerca i Societat de la Informació de la Generalitat de Catalunya for her research fellowship To all co-authors of this work 27
Thank you for your attention gperez@diei.udl.cat jcoma@diei.udl.cat 28