dc.description.abstract |
Global warming and energy crisis are two of the biggest issues the world faces today which
require immediate mitigatory actions. Building sector plays a major role in contributing to
these issues due to the high energy consumption and carbon emissions. Highly dense
urbanities directly contribute in urban heat island effect thus local warming. Therefore,
researchers have given considerable interest on the building envelop design with the concerns
for energy efficiency, aesthetic appearance and sustainability. As a result, integration of
green facades with buildings has rapidly evolved due to the aesthetic appeal and sustainable
benefits such as uplifting the urban environmental conditions by promoting air quality,
reducing heat island effect and etc. However, adaptation of vertical greenery is still at an
initial stage in Sri Lanka.
The research was initiated to introduce vertical greenery to a broader context and to develop
an innovative modular green wall system for building facades as a sustainable building
envelop in Sri Lankan context. Field studies were conducted in identifying the potential of
introducing a vertical greening system and benefits of existing vertical greening systems in
tropical Sri Lankan context. Modular panel and green wall system development was
conducted as on-site experiments and the thermal performance evaluation and long-term
benefits of the proposed modular panel vertical greening system was conducted as on-site
investigations combined with software simulations.
Results of the field investigations on the perception on vertical greening in local context
demonstrated that general public, building occupants and the building designers are willing
to accept the vertical greening as a sustainable approach for buildings. Yet, lack of knowledge
on the vertical greening systems, maintenance methods and their benefits and misconceptions
on related costs have impeded the popularization of vertical greening. Identified existing
vertical greening types in local context; living walls, indirect and direct green facades are
beneficial in reducing the surface temperature of buildings where living walls recorded the
highest temperature reduction of 10.15
o
C. Internal air temperature reduction was recorded to
be 2.21
o
C, 1.82
o
C and 0.66
o
C by living wall, indirect green façade and direct green façade.
Pilot and extended field investigations on plant selection for the proposed vertical greening
system resulted in shortlisting two species, from which Axonopus compressus was selected as
the best plant species where a maximum 10.08
o
C external wall surface temperature reduction
and 3.15
o
C internal surface temperature reduction was recorded. The experimental studies on
finalizing growth media resulted 1:1/2:1/2: 1/4 coir: sand: compost: soil ratio as the growth
media with the best compaction and the permeability for the plant growth in the proposed
vertical greening system. Proposed system is advantageous as it can be easily introduced to
existing structures and as the panels can be handled separately allowing easy installation and
easy replacement with minimum technical support. Size of the modular panel was finalized as
600mm (width) x 900mm (height) for easy handling and the fiber was selected as the material
due to strength and durability.
Developed walling system recorded a surface temperature reduction of 17.26
C in
external wall and internal wall surface and a temperature reduction of 2.89
C of internal air
temperature. Simulation studies conducted in building scale and urban scale resulted significant
indoor air temperature reduction, cooling load reduction and urban air temperature reduction
when integrating the proposed modular panel green wall whereas the quantifiable long-term
benefits are achievable in terms of savings from energy consumption and façade maintenance
and numerous un-quantifiable benefits related to sustainability and health. |
en_US |