OFF | Kill Bill 4 | Net Zero Skyscraper

Let’s get to Zero!

“India has increased its green-certified floor area exponentially from just 20,000 SF in 2004 to 775crore SF in 2021. Formulation of Energy Conservation Building Code marked an important step in incorporating efficient practices into the building sector. It is a conscious decision for future development to make buildings energy efficient. Core and shell projects are lucrative options for the commercial sector, providing flexibility to the tenants.

Ensuring that skyscrapers provide an energy-neutral comfortable indoor environment is challenging. Limited roof space is a major hurdle in achieving Net-Zero energy solutions in high-rise building projects. Team KillBill 4.O from CEPT University has taken up this challenge and has tried to develop innovative solutions to achieve a Net- Zero 24 storey commercial complex.

Team KillBill 4.O is a combination of architects and engineers with varied backgrounds and experience. The team has partnered with ATS Savvy Developers LLP, whose mission is to strive for quality construction, architectural designs, and conscientious attention to detail. Our project, Pragya, is a 24 storied (commercial/ office with multi-level car park) complex located in GIFT city, Gandhinagar in Gujarat. We aim to provide the most cost-effective net-zero energy-water solution by integrating the various infrastructural needs of our project with centralized systems provided by the GIFT City while maintaining the individuality of the project.
In a high-rise project, the facade is the largest external surface. We have tried to create to produce a facade design that appeals to its target market in terms of appearance and aesthetics but also is utilized effectively as potential surface area to host carbon positive elements. The focus has been to reduce not only energy consumption but also address the challenges of affordability and marketability in a core and shell project that suffers from the classic problems of split incentives and the need for universal appeal to ensure continuous tenancy. The team tested the feasibility of a wide set of design solutions such as solar absorbers to develop a Hybrid Solar Thermal HVAC System to identify viable solutions that work from multiple points of view. In the particular case of the cooling plant type all tested technologies (low/lower-carbon) failed to complete with high-performance district chilled-water system in terms of energy efficiency and cost. The team proceeded with roof and façade solar PV systems.

With a built-up area of 37000 m2, our building has been designed to achieve an EPI of 45 kWh/m2yr, achieving its net-zero target through solar PV generation with a safety fact of 10%. The GIFT city chilled water supply system makes a large contribution to the exceptionally low EUI due to the high diversity factor in the operation of the district system (COP = 6.65). In addition, in most core and shell projects, most tenant guidelines are limited to efficient fixtures (lighting and terminal units). Our proposal shows that to achieve net-zero status in core and shell buildings, it is necessary to expand the scope of the tenant guidelines to operations as well. A 16% reduction in the potable water supply is attained by reducing water usage by efficient fixtures, drip irrigation for landscape, 100% on-site rainwater and storm water management, and sewage treatment. By using a radiant cooling system, achieved a reduction of 70% in HVAC energy consumption.
Green buildings create a long-term value to all the stakeholders in a project, but due to a lack of awareness about the green component, investors have not paid much attention to core and shell office projects in India. A Build Own Operate and Transfer (BOOT) business model for a large-scale replicable building-integrated Solar Photovoltaic array is proposed by allocating the installation, operation, and maintenance to an energy service company (ESCo.). The Solar PV array of 1081 kWp capacity with an upfront cost of 5.14 Cr has an annual ROI of 11%, which breaks even within 11 years. This proposal interests the investors as the net present value for the solar PV is 2.84 Cr.
The resulting design achieved total FSI with an incremental construction cost of 3% (4.2 Cr.) to the developer yielding an internal rate of return at 20.75% and saving an average of Rs. 2.0 Cr. on the operational expenditure of building for occupants every year. The life-cycle cost is reduced by 6% for a calculated period of 25 years, at a discount rate of 10% after implementing the design solutions.

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