Green conversations: UNNATI

A high-performance commercial building

UNNATI is a 3-storey, 4,945 sq.m (53,208 sft) office building for the heavy machineries and construction equipment company – GAINWELL CAT, located in its industrial campus in Greater Noida. With an EPI of 60 kWh/sq m/year, the building design is an example of how climate responsive architecture is integral to achieving energy efficiency in a composite climate.

The webinar brought on board the project manager, architect and sustainability consultants to share insights about the integrated design approach and challenges behind the project

Unnati- a climate-responsive office building

The clients had the vision of developing a world-class, ecologically responsible facility for their employees. The intent was to create a happy workplace, minimize pollution, provide a connection with the natural environment, create a culture with shared ecological ethos.

Architect Ashok B Lall brought his decades-long experience in low-energy sustainable architecture to the table while MEP Consultant Vevaik Mahajan brought in his expertise in low-energy cooling. The resulting design exemplifies an integrated design approach- seamlessly unifying the structural design, the architectural design and the services to create a high-performance building.

The office building is designed around a central courtyard

The key factor to the project’s energy efficiency is its building envelope which consists of insulated walls and glazing, as well as a green roof and innovative shading strategies. This façade consists of ‘boxes’ protruding outward from lower and upper levels of the fenestration on each storey- that are insulated, cleverly designed to serve as shading devices on the exterior and light shelves to enhance daylighting on the interior. Below the fenestration, the ‘boxes’ house the HVAC ducts. The architects experimented with a unique type of sandwich construction for the façade- consisting of XPS, reinforcement and sprayed concrete.

Let’s now discuss the project’s unique cooling system. Along with the standard chilled water system, the building uses a radiant cooling system, improving the chiller efficiency by 50%. Displacement ventilation ensures a more efficient supply of clean, fresh air directly to occupants.

The project also houses a 100 KW rooftop solar plant over the adjoining workshop building making this a nearly zero building. Grey water and industrial effluent are treated on-site, and reused in the cooling towers, toilets, and for irrigation. The facility also manages organic, inorganic and toxic waste responsibly.

The clients decided to go for green building certification post-construction. Given its thoughtful design, the project could easily comply to LEED v4 BD+C’s stringent requirements and went on to achieve the Platinum certification- a first in India! Thus, the key takeaway from the project is that high performance design need not be complex!

This webinar was conducted on 17th May, 2019

Ashok B Lall | Project Architect

He is the Principal at ABL Architects and specializes in low-energy sustainable architecture. Recent projects in India include the Indian Institute of Health Management Research, Jaipur; Sehgal Foundation, Gurgaon and Development Alternatives World HQ, New Delhi.

Vevaik Mahajan | MEP Consultant

Vevaik Mahajan,director at UEDC, is an engineer by profession having over 16 years of Industrial experience in the field of MEP/FP. Having worked in US and India, his knowledge base is in the healthcare, Institutional, Industrial and commercial sectors.

Mariyam Zakhiah | Green Building Consultant

A graduate in architecture from Jamia Islamia, New Delhi and Architectural Association, London, she has expertise in certification facilitation and environmental simulation. She is also involved in developing policy documents for implementing Energy efficient buildings at the state and national level.

Q1. Was there any zoning- like perimeter and core zones- for office space- for space conditioning systems?

Yes. The periphery zones that are under more exposed conditions are supplied by higher CFMs than the interior zones.

Q2. What active measures were taken to avoid condensation on chilled slab surface?

We installed slab sensors that maintain and monitor surface temperatures of the slab to ensure they don’t go below dew point.

Q3. What is the role of the fountain in the courtyard?

The pool was being built as a landscape element. Initially, we were planning to integrate the fountain in it in the air conditioning system as a heat sink or cool water storage, but this was dropped. We built this fountain into it- it’s a trickle fountain and rises up 2 storeys high. When it’s run for long periods, it helps cool the microclimate.

Q4. When we are using water as a coolant in radiant cooling, could there be challenges due to maintenance of pipes due to salt accumulation?

Not really. Lower side system is a closed loop system and very little new water gets added. Further, the piping material chosen doesn’t allow accretion of salts in its surface.

Q5. While there are box-shaped shading devices on all facades, the south west façade has a linear projection. What is the reason for this?

The South-West façade is more exposed to the movement of sun. The box projection wasn’t sufficient. Further, the pergola over the façade will soon have creepers along with tall palms in the front that will further shade it.

Q6. Can Truss reinforced concrete be used in high rise structures?

The Truss reinforced concrete is not a load bearing material. It’s just a lightweight insulating material that can be applied to any building- both low-rise and high-rise. The product is an insulating material sandwiched between galvanized steel meshes. Concrete is sprayed on both sides to make a wall.

View webinar presentation-UNNATI- Headquarters for GAINWELL CAT

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