Green conversations: HQ of Ministry of New & Renewable Energy (MNRE)

A net-zero energy commercial building

The Ministry of New and Renewable Energy (MNRE) is constructing a new headquarters in New Delhi- Akshay Urja Bhawan, designed to be Net Zero Energy. The project uses a combination of climate responsive architecture with energy efficient technology to achieve this goal. It has been conceived as a 10-storeyed, 2,38,368 sft office space within a 2.76 acres site, with a north and a south wing connected by a service core.  In the webinar, the project architect Bedanta Saikia and MEP consultant Samdarsh Nayyar break down the approach, design strategies and challenges behind the upcoming iconic addition to Delhi’s skyline.

urja bhawan pic

The design team’s journey began with winning the competition for designing the MNRE’s new headquarters. Net-Zero energy was a key part of the design brief right from the beginning. For the team, the first step towards this was lowering the building energy demand using passive design strategies like proper orientation, massing strategies, shading and opting for energy efficient building systems. The next step was integrating solar photovoltaics into the building to meet this demand.

The team had a challenging site on their hands, one that was narrow and oriented along the unfavourable East-West direction. Their response was to tilt the South Wing to maximise its exposure to the North-East light. Further, an ancillary services core was planned along the western end to act as a heat buffer. Insulating double walls are used for the envelope.

On the systems side, the building uses a hybrid cooling system with a conventional and a radiant chiller, 215 TR each. Radiant chillers are about 33% more efficient- and they also don’t require big Air Handling Units. Further, the fresh air system is pre-cooled by toilet exhaust. The Building Management Systems is programmed to put a cap on the building load and optimize the running of various systems.

Let’s now look at the on-site energy production. Along with the ‘Solar Wall’, the building also has an integrated solar roof and together these can potentially generate up to 5295 kW-hr on an average every day. Compare this to the building’s daily average energy consumption of 5126.6 KW-hr and it’s well poised to achieve the Net Zero Energy mark!

The team’s integrated approach is evident in the design details. For example, a ‘solar wall’ helps shade the building facades while providing on-site power. Vegetated screens connect occupants to nature while providing diffused daylight indoors and improving air quality.

The MNRE HQ’s design reinforces the fundamental approach towards achieving net-zero- first reduce your energy consumption and only then look at a renewable energy supply.

This webinar was conducted on 28th May, 2019.

Bedanta Saikia | Project Architect

He is the Vertical Head at Edifice Architects and heads the Corporate Archtiecture Practice. He is committed to sustainablityand consciously tries to reduce the carbon footprint of his projects by sensible yet relevant use of materials and processes.

Samdarsh Nayyar | MEP consultant

He is the founder of Green Horizon Consulting, LLP, a green building and sustainability consulting firm and a Director in Sunil Nayyar Consulting Engineers (SNC), one of India’s leading MEP consulting firms. An engineer by education, he has a very strong backround of designing resource-efficient Building Services and has been involved in MEP designing of a number of projects  including Lemontree Hotel @ DIAL (LEED Gold), 183 @ Nimitaya (LEED Platinum), 108 @ Nimitaya (LEED Platinum), Chandigarh Airport (GRIHA 4-star), Milestone Experion Center (GRIHA 5-star), Pearl Global Chennai (LEED Platinum).

Q1. How did you integrate the jaali into the soffit of the roof? What is the material used? Is it a false ceiling or structural?

Unfortunately, it’s a false ceiling hiding the structure above. So we are looking at probably doing it at Glass fiber reinforced concrete (GFRC) option.

Q2. Is this structure to support the solar panels on the roof part of the FAR?

No, it is not part of the FAR.

Q3. What impact does the vegetation have on water demand?

As human beings, we need to have a direct connect with nature and we didn’t want to compromise on this. The water demand for the irrigation can be reduced by using drip irrigation. We can ensure that the building itself meets the water demand by using recycled water.

Q4. what has been your strategy for selection of the materials?

See normally for a green building. We look at materials that has been less embodied energy. Another key strategy was selecting materials from within the vicinity.

Q5.  Can you give an estimate of the cost difference between conventional office building and an NZEB ?

As far as the architecture is concerned, no. As responsible Architects, this is our responsibility to make any architecture as energy efficient as possible anyway.  If you’re going for Net Zero, there is the additional cost of generating your own energy.

If we had built a conventional building, it would have cost us Rs. 4800 per square foot, including the civil work, structure, MEP and interior finishes. As an NZEB, it costs approximately Rs 5600 per square foot, including 1 MW solar PV generation. If we omit the PV system, the cost would further come down to Rs 5100-5200 per square foot. So, it costs about 7-8% more than a conventional building.

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