vertical greenery systems (vgs) for energy savings in .......

Vertical Greenery Systems (VGS) for energy savings in buildings

International Green Wall Conference

4-5th September 2014

Stoke-on-Trent, UK Julià Coma Dr. Gabriel Pérez Dr. Cristian Solé

Dr. Albert Castell Dr. Luisa F. Cabeza

2 International Green Wall Conference 4-5th September 2014, Stoke-on-Trent , UK

Contents

• Introduction

• Objectives

• Previous research

• Current research

• Further research

• Conclusions

• Acknowledgements


• 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

Thuir. France

Pergola Building

Belén, Costa Rica


Introduction

• The classification of VGS must be taken into account for energy savings purposes

Extensive systems Intensive systems

Traditional

Modular trellis

Wired Double-skin

Mesh

Green façades

Perimeter flowerpots

Panels Living walls

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


• 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

Introduction


• Difficulties to measure the influence of VGS on building

thermal performance: – Differences between constructive systems

– Living organisms (species, growth, diseases, etc)

– Different climate conditions

– Difficulties to quantify the effects individually

Introduction

Sihlcity Greenwall, Zurich


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

http://www.grea.udl.cat/


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

Radiació

solar

incident

paret

Radiació

solar

incident

exterior

Tª 3, HR 3

(z = 3m)

Tª 1, HR 1

Exterior

Tª 2, HR 2

(z = 1,5m)Tª 4, HR 4

Interior

Action 1 Action 2

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


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).

LUXOMETER

0,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

9 h 10 h 11 h 12 h 13 h 14 h 15 h 16 h 17 h

Hora

Tra

nsm

isiv

ida

d lu

mín

ica

Viña virgen Madreselva

Clematide Hiedra

Artificial barrier shadow factor

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


Previous research

• Action 2: Thermal behaviour of green facades in an existing cubicle. 2010-2011


Previous research


– 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)


Previous research


– 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)


Previous research


– Some energy savings was observed for the accumulated energy consumption under indoor controlled conditions (24 ºC)

0

2

4

6

8

10

12

07-07-11 08-07-11 09-07-11 10-07-11 11-07-11 12-07-11

En

erg

y [

kW

h]

Day

Green facade Reference

Accumulated energy consumption by the heat pumps.

July 2011. Set-point 24 ºC


Current research


– As the previous results were positive, a new green facade have been

built, covering the east, south and west walls



– Deciduous vegetation (Boston Ivy, Parthenocissus Tricuspidata) was planted in June 2012 and was growing during summer 2012 and spring 2013

Current research


Current research

• Data from summer 2013 show the shade effect, with a set point of 24 ºC

15

20

25

30

35

40

45

50

10-7 0:00 10-7 6:00 10-7 12:00 10-7 18:00 11-7 0:00

Tem

pe

ratu

re (

ºC)

PeriodSouth internal wall green facade South internal reference roofOutside temperature South external wall green facadeSouth external wall reference roof

Green facade; South internal wall

Outside

Reference; South external wall

Reference; South internal wall

Green facade; South external wall

15

20

25

30

35

40

45

50

10-7 0:00 10-7 6:00 10-7 12:00 10-7 18:00 11-7 0:00

Tem

pe

ratu

re (

ºC)

PeriodSouth internal wall green facade South internal reference roofOutside temperature South external wall green facadeSouth external wall reference roof

Green facade; South internal wall

Outside

Reference; South external wall

Reference; South internal wall

Green facade; South external wall

7ºC


Current research

• And interesting energy savings (set point 24 ºC), up to 50%

0

2

4

6

8

10

12

14

16

2-7 3-7 4-7 5-7 6-7 7-7 8-7 9-7 10-7 11-7

Reference roof Energy green facade

Acc

um

ula

ted

ele

ctri

cal

en

erg

y co

nsu

mp

tio

n [

kwh

]

Reference cubicle Green façade cubicle

0

2

4

6

8

10

12

14

16

2-7 3-7 4-7 5-7 6-7 7-7 8-7 9-7 10-7 11-7

Reference roof Energy green facade

Acc

um

ula

ted

ele

ctri

cal

en

erg

y co

nsu

mp

tio

n [

kwh

]

Reference cubicle Green façade cubicle


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


Current research

• Data from summer 2014 with a set point of 24 ºC. The shade effect was confirmed for the Green Wall too

10

15

20

25

30

35

40

45

50

15-7 0:00 15-7 6:00 15-7 12:00 15-7 18:00 16-7 0:00

Tem

pe

ratu

re [

ºC]

PeriodGreen Wall; South internal wall Green Facade; South internal wallReference; South internal wall Outside temperatureGreen Wall; South external wall Green Facade; South external wallReference; South external wall

12 ºC 17 ºC


Current research

• Data from summer 2014. Energy savings of more than 50 %

0

1

2

3

4

5

6

7

9-7 10-7 11-7 12-7 13-7 14-7 15-7 16-7

Period

Acc

um

ula

ted

ele

ctri

cal e

ne

rgy

con

sum

pti

on

[kw

h]

Green Wall Green Facade Reference


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

• 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

Pérez G. et al. Vertical Greenery Systems (VGS) for energy saving in buildings: a review. Renewable and Sustainable Energy Reviews (2014), pp. 139-165


Further research

– Most of the studies found are located in Europe (mainly Green Façades) and Asia (mainly Green Walls).


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


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


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


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


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


Thank you for your attention

[email protected]

[email protected]

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