Net Zero Buildings are the Need of the Hour

Ar. Dhruv K Futnani, Managing Director, Green by Dhruv Futnani Ar. Dhruv K Futnani, Managing Director, Green by Dhruv Futnani and LEED (USGBC) & IGBC Accredited Professional,  in an interaction with Built Expressions suggests that it is always better to consider the materials and systems based on the climate of site, function of space and design characteristics of the project; these are always project specific.

BE: As an architect, how do you visualize a future eco friendly city? What important parameters of built environment this city shall address?

DKF: I visualize and "eco friendly city" as a development where the buildings are green and people are greener! For a truly sustainable development, the built environment should be green and it is equally important for the occupants to understand how to utilize them properly and have the sensitivity to protect the environment. How often have we seen efficient technologies which are an utter waste due to improper usage or installation?

Any project will consume resources, but projects can be designed to be net zero energy and net zero water. Energy Efficient buildings supplemented by renewable energy already exist. Rain water harvesting, water saving toilets supplemented by sewage treatment plants is also important to conserve water. "Waste" will be generated in any project during construction and post occupancy, but the proper recycling and reuse or disposal can mitigate this problem. Green Buildings are the first step, net zero buildings are the need. The technologies are available currently, so it’s not a distant dream, but it requires a change in vision and values of the people involved in the construction industry.

BE: What are the energy efficiency options that should be made mandatory in a building at the time of plan approval? Are there any steps initiated by the concerned authorities in this direction?

DKF: Energy efficiency should be mandatory in any building; a few green buildings are not going to solve the energy crisis. The impact of energy efficiency is far greater than operational savings for the owner, but impacts the infrastructure, city / town and the environment.

Any building (AC or non AC) should meet the minimum requirements for energy consumption and indoor environment. The minimum parameters like building envelope, artificial lighting and air conditioning systems should be enforced. For LEED certified projects, a project has to show the energy consumption is less than a "basecase" building over a year and to earn points, the percentage of savings over basecase need to be substantiated.  Most countries make this compliance with the energy code mandatory for approval, but in India, ECBC is still not mandatory. A building which consumes 2 or 3 times more energy, utilizes inappropriate materials & MEP systems and provides spaces with no daylight and ventilation can be constructed, simply because it meets the norms of setback, building height, fire safety etc.

To encourage sustainable projects, project showing greater savings should be given fast track approvals and reduction in fees. Also, the commissioning of these materials and systems is paramount to ensure buildings operate as intended and energy savings are actually accrued. Penalties (like higher cost per unit of electricity) for inefficient buildings also reduce such "energy sink projects".

BE: What is the impact of embodied energy of construction materials in the construction of High Performance buildings for sustainable future?

DKF: I believe that the choice of materials and systems selected in a project should be through calculations, simulations and common sense through the appropriate and intelligent use of materials. It is prudent to use materials with high recycled content, recyclable after its intended use and promoting the use of local materials, but only if these materials are required and appropriate for the project.

Glass is a great example for this philosophy. With the proper daylight and energy modeling, the area and orientation of glazing and specification of glass and shading systems can be determined to optimize the building. When used improperly used, the increase in energy consumption for artificial lighting and air conditioning (due to increased heat gain) will certainly negatively impact the project, probably more than the impact of embodied energy.

Many traditional materials are considered to be sustainable and having low embodied energy, but the context in which these materials are used are more critical. A material with high thermal mass is ideal for naturally ventilated spaces, but when used in an air conditioned space, these materials increase air conditioning loads and this increase is energy consumption probably negates the low embodied energy of the material. Always consider the materials and systems based on the climate of site, function of space and design characteristics of the project; these are always project specific.

Climate responsive design and common sense are the key to material selection.