Cracking the Myth of Solar Façade Cladding

Fig. 2: Comparison between the Solar Photovoltaic glass and conventional glass (Source: Onyxsolar) with a chamber of 12mm filled with air and rear glass of 4+4mm float glass with LowE coating. The total power installed is 27.35kWp

Below details - FIg.3 & 4 - is the outcome of the feasibility study: lElectricity generated in 35 years: 511,193 kWh lEnough energy to feed 1004 light points working 4 hours per day for 35 years lEnough energy to prevent the emission of 438 tons of carbon dioxide

Fig. 1 shows a photovoltaic power potential map. We need to focus on capturing the solar to harvest energy.

Building façades with conventional curtain glazing can be replaced with Solar Photovoltaic Glass to harvest energy. Fig. 2 shows the comparison between solar photovoltaic glass and conventional glass.

Solar photovoltaic glasses are of two types: Amorphous silicon glass and Crystalline silicon glass, both are available as opaque and with various levels of transparency. The peak power generated by each type also varies, hence while selecting the type of glass, due care needs to be provided. The below image shows the look and feel of the Amorphous and Crystalline silicon PV glass. Whereas Amorphous glass can be proposed for the area where we require more aesthetics - like the façade area, crystalline can be proposed where it doesn’t require more aesthetics - like the skylight area.

Fig. 5 shows the proposed office building with the solar photovoltaic facade, total integration area considered is 972 Sq m with amorphous silicon technology having a 30% transparency degree. Glass configuration is 6+3+6mm

Fig. 3: Solar photovoltaic glasses are of two types: Amorphous silicon glass and Crystalline silicon glass, both are available as opaque and with various levels of transparency

Fig. 4: Degree of Transparency of Amorphous Silicon PV glass (Source: Onyxsolar)

lEnergy generated in 35 years: 87,05,733 INR lNet investment: 54,29,841

INR (Photovoltaic Glass cost – Conventional Glass cost +

Electrical installation cost lPayback period: 12 years lBy installing solar photovoltaic glass, the project can reach up to 8 LEED credits (Renewable energy production on-site: up to 3 credits, Heat Island Reduction: up to 2 credits, Optimise energy performance: up to 2 credits,

Innovative product: up to 1 credit)

Cost and other benefits: We can generate our own electricity from the sun. 40% reduction in the HVAC cooling load, 20% reduction in the lighting load, achieve daylighting, reduce peak energy demand, reduce operational cost and aesthetically integrated.

Challenges: Include initial investment, the cost of the product, aesthetic reasons, performance, unavailability of codes and standards, availability in the market since there are very few manufacturers, additional

Fig.6: Challenges in installing solar photovoltaic facade (Source: Technical article published in Journal of Facade Design and Engineering)

Fig. 5: Proposed Office building with solar photovoltaic façade

Fig. 7: A roadmap to 2050 prepared by the International renewable Energy Agency, where we are at 109 GW of solar power generation, which is targeted to achieve 360 GW by 2050 (Source: International Renewable Energy agency report)

labour cost due to specialised installation, lack of awareness of the new technology & material, and need for extra maintenance. The image (Fig. 6) shows the survey result, and the size of the text shows the frequency of occurrence during the survey.

Source of details are taken from Global Energy transformation – a roadmap to 2050 prepared by International renewable Energy Agency (Fig.7), where we are at 109 GW of solar power generation, which is targeted to achieve 360 GW by 2050, and we could also see the photovoltaic levelised cost of energy had reduced drastically from 347USD/MWh in 2010 to 81USD/MWh in 2018, and is expected to still lower to 38USD/ MWh, this is mainly due to new materials and technologies. We need to grow from 36% to 81% of generating electricity thru renewable energy. To conclude, little drops of water make a mighty ocean. Every small effort towards sustainability makes the world liveable for the future generation.

S.N.MAANVIZHI

Discipline Manager - Architect L&T Technology Services Limited

ABOUT THE AUTHOR:

Maanvizhi completed Bachelor of Architecture from Bharathidasan University and Masters of Town and Country Planning from the School of Architecture and Planning, Anna University, Chennai. She is working with L&T Technology services for the past 15 years. Her expertise includes master planning, building design and interior design and executed larger scale Greenfield manufacturing facilities to Brownfield expansions in India, Vietnam, U.A.E, Indonesia. Maanvizhi is an IGBC Accredited Professional and she is passionate to create a sustainable built environment.

International school in Copenhagen integrated with solar panels

Cracking the Myth of Solar Façade Cladding

Face is the index of mind”, a widely used English proverb which means that the face replicates our thoughts, sentiments and emotions. In the field of architecture, it is the façade of a building that depicts the creativity, emotions, and thoughts of the architect, and reflects the character, function and value of the building. Nowadays, façades are designed using different types of materials. Glass, terracotta, HPL laminates, ACP and even plants, thereby promoting green façades.

Façades protect buildings for the external influences such as rain, wind, heat and radiation from the sun.

The sun has been a source of clean energy early as the Egyptian civilisation, the technology and applications of using the sun have evolved to harnessing the sun from a façade. Consequently, the global installations of solar façade cladding - also known as BIPV (building integrated photovoltaics) - is set to grow at an impressive rate of over 15 per cent until 2024. Now, pro-active architects are beginning to embrace the technology followed by other stakeholders like the users, government, property developers and policy makers that will propel the growth of this technology.

In this article, we explore further into the different types of impacts and aspects of a technology like solar façade cladding has on earth, mankind and economics.

Black and blue appeal of solar façades

Textures, colours, BIPV

TECHNICAL ASPECTS

India has witnessed solar integrated façade as early as 2008. However, the technology has not taken off as expected both in India and across the world. During the initial days of the technology, solar façades often wore a black/blue appeal which has been one of the main concerns of the architects which led to the disinterest from the architects. Fortunately, the technology has evolved across these years to the extent that it can be manufactured in various colours and even textures much to the awe of architects. Although one of the key challenges that remain is to train the façade contractors and installers on the technology and installation procedures.

ECONOMIC ASPECTS

Solar façades are becoming attractive due to the growing awareness of architects and consultants largely to the flexibility in design, colours and textures. Unlike a normal façade, BIPV or solar façades offers one key economic benefit i.e., it offers an ROI, thus making it financially solar façade is specified in square feet being a building material. A key contributor to the price of a BIPV or solar façade is the cost of professional labour. The labour needs to be skilled and accurate as it involves various technical parameters that are accounted during installation. Eventually, this cost can be reduced by training installers on the technology of solar façades. Thus, BIPV creates a new attractive market opportunity for well-organised, professional companies in the market of architectural façades.

ENVIRONMENTAL IMPACTS

Mankind is fighting its existence from Paris to Katowice. There is a growing concern about climate change across the world. One of the key contributors to climate change has been carbon emissions emitted from power plants. Burning of fossil fuels like coal, petrol, gas not only emit carbon that leads to climate change, but also toxic gases and particles that contribute to air pollution. India’s stance on nuclear power as a clean

attractive for the building owner as well as the user. However, the investment cost remains high when compared to a solar application on a rooftop. This is often related to the misconception that exists between solar rooftops and solar façade. Decision makers understand that solar rooftops use solar panels often sold in terms of watts; the amount of energy that it can generate. A

Skill development is necessary when promoting BIPV in India