Business Today

Zero-energy Buildings

A sneak peek into India's first zero-energy building.
twitter-logo Sarika Malhotra        Print Edition: August 16, 2015
Zero-energy Buildings
Indira Paryavaran Bhawan (Photograph by Vivan Mehra)

INDIRA PARYAVARAN BHAWAN

G+7 storeyed plus 3 basements

NET ZERO ENERGY: Rooftop solar PV system; total area taken up by solar panels is 4,600 sq. m. Annual energy requirement and generation: 14 lakh Unit kWh; cost of installation: Rs 18 crore

BRINGING IN THE LIGHT: The building is designed to ensure daylight in 75 per cent occupied area

CHILLED BEAM AIR CONDITIONING: Air conditioning by convection currents rather than air supply through ducts; chilled water circulated right up to diffuser; more than 50 per cent saving in energy consumption on air conditioning

WATER CONSERVATION:
Recycling of waste water through sewage treatment plant; sensor urinals and dual flow cisterns; rain water harvesting

FUTURISTIC CAR PARKING: Fully automated robotic car parking for 330 cars; single car retrieval time: 3 minutes. Cost of development: Rs 17 crore

FULL COVERAGE:CleanTech 2015

Government buildings are supposed to be dull and uninspiring, have high energy requirements and are, consequently, polluting. But Indira Paryavaran Bhawan, the building in New Delhi that houses the office of the Ministry of Environment, Forests and Climate Change, is different. Built at a cost of Rs 209 crore, it is India's first building certified by GRIHA for Exemplary Demonstration of Renewable Technology. It is also hailed as India's first zero-energy building. What's that? A zero-energy building harvests energy on site to meet its energy demand. In other words, a building whose annual energy consumption is equal to the renewable energy it generates on site. It also uses much less energy than conventional buildings. Typically, technologies such as solar cells, wind turbines, solar thermal collectors connected to thermal storage equipment are used to harvest energy.

INTERVIEW

Arun Shenoy, co-founder and Executive Director/ GIBSS
Q- How can buildings attain optimum zero energy levels?

A- Buildings can achieve zero energy levels in two steps. One, reduce demand through commercially viable energy efficiency technologies such as geothermal air conditioning and LED lighting. And two, harvest energy on site to meet the already reduced demand by using technologies such as solar cells, wind turbines, and solar thermal collectors connected to thermal storage equipment.

Q- What will be the difference in investments in energy of a conventional building and a zero-energy building?

A- Pursuit of a zero-energy building without reducing demand first can be disastrous, resulting in very high investment costs, poor payback, significant usage of open space and, most importantly, disillusionment towards zero energy concepts. It's important to create a roadmap that in its first phase focuses on reducing demand to the highest extent possible with technologies and strategies that are commercially viable. To understand this concept, imagine a building consuming 100 units of energy a year. Let's say 65 units is consumed by the air conditioning system, 10 units by the boilers to generate hot water, 15 units by lighting and 10 units by other equipment. The building will need to harvest 100 units of energy through supply-side solutions and make capital investment for this requirement. On the other hand, demand can be reduced through ultra-efficient commercially viable technologies such as geothermal air conditioning. In the above scenario, the building has implemented demand-side technologies first, thereby reducing demand from 100 to 45 units. Now, the building will need to harvest only 45 units of energy through supply-side solutions and invest only for this amount.

Q- How can the concept of zero-energy buildings catch up in India?

A- A lot of awareness needs to be created on the process and the path to achieve zero energy to ensure that building owners take up demand-side initiatives before introducing supply-side solutions. Since air conditioning accounts for more than 60 per cent of the energy consumption in most building verticals, commercially viable solutions with payback of less than two years such as geothermal air conditioning must be made a mandate to meet the base load demand in all commercial and industrial buildings. Other supply-side technologies have to be made commercially viable by manufacturers and market players rather than through government subsidies and accelerated depreciation benefits.

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