| dc.description.abstract | The renewable energy share in the energy mix worldwide is rising sharply to mitigate
climate change, with Solar Photovoltaics (PV) carrying a large share of 3.6%. However,
the end-of-life (EoL) management of decommissioned PV panels is emerging as a serious
concern, globally. It is projected that by the end of 2050, a cumulative 70~80 million tonnes
of EoL-PV waste will be generated worldwide, with 4.5~7.5 million tonnes envisaged in India.
Such enormous PV waste heading into landfills severely threatens the environment and
human health. The current study explores a novel, hitherto untried, approach of upcycling
EoL-PV panels as a building material. EoL-PV also carries potential for application in housing,
alleviating the pressure on conventional building materials. Further, upcycling PV panels could
extend the use-phase by a few decades, buying time till recovery and recycling options
become economically viable.
For application as a building material, EoL-PV panels need to be examined for their solar and
thermal transmittance. PV panels, before they reach end of functional life (EoL), undergo
degradation subject to various field (environmental) and operating conditions. The impact of
degradation on the solar and thermal transmittance of EoL-PV panels has not been examined
thus far. About 33 decommissioned EoL-PV panels with various degradation modes have been
visually and electrically examined along with 2 new(unused) PV panels. EoL-PV panels are
non-opaque materials, and hence solar transmittance measurements could provide crucial
insight into their climatic performance. Further, the impact of degradation on solar and
thermal transmittance has been examined, comparing EoL-PV panels and new (unused) PV
panels. The measurement approach adopted (under natural sunlight) has been a maiden
attempt in examining PV panels. ASTM E1084-86:2015 stipulations for such measurements
have been complied with. Compared with new PV panels, a drop in solar transmittance of 11
% ~ 37.6 % has been observed in EoL-PV panels. Both EoL-PV and new PV panels have also
been tested for their thermal transmittance in a state-of-the-art HotBox facility. No significant
changes between EoL-PV and new PV in their thermal transmittance were observed. The
absolute U-values were in the range of 11.7 W/m2
K ~ 12.5 W/m2
K, with their thermal
conductivity in the range of 0.55 ~ 0.7 W/mK.
The climate responsiveness on EoL-PV building has been examined for various climate zones
in India. This has involved a real-time monitoring of a case study building (building integrated
with EoL-PV as façade), supported by whole-building simulation models. Time lag and
decrement factors are parameters to examine the climatic response of a building envelope.
The time lag for the EoL-PV case was observed to be very low (< 1 hour), and the decrement
factor around 1. The thermal damping was found to be negative, indicating that the indoor
air temperature is higher than outdoor ambient temperatures. For tropical conditions such as
India, this would imply a large heat gain, which is not favourable. Suitable interventions need
to be devised to improve the thermal performance of the EoL-PV envelope. Four interventions
have been proposed and tested through whole building simulations. Significant improvement
in the decrement factor (0.4 ~ 0.7) and time lag (6~8 hrs) have been achieved for favourable
adoption in tropical conditions.
Given the huge demand in housing, the current study has examined the applicability of EoL PV for housing and in alleviating the demand for conventional building materials.
Conventional building materials are energy intensive and carry a huge carbon footprint. There
is an emerging paradigm shift in the adoption of novel building materials with low embodied
energy. EoL-PV is an affordable and durable material with an inherent low embodied energy.
From a sustainability perspective, the current study also examines the energy, cost and
carbon-emission benefits accruing through the adoption of EoL-PV buildings in comparison
with conventional buildings. EoL-PV panels carry inconsistent degradation, which depends on
the age of PV, climate zone and other factors. An approach has been developed to determine
the probability of degradation modes for a given climate zone, including the impact of
climate-change. Based on this, state-wise projections on the number of EoL-PV panels likely
to be generated in India, and the minimum number of houses adopting EoL-PV has been
estimated as part of this study.
The result from the study strongly favours the application of EoL-PV as a building material
with appropriate interventions customised to achieve indoor thermal comfort in response to
the prevalent climatic conditions. This makes EoL-PV a valuable decentralized resource with
potential to support Net-zero buildings | en_US |
