Green technologies to build eco-friendly buildings

Green building isn’t just a way to conserve energy but also our responsibility towards our future generations
Increased human activities are causing irreversible damage to the global environment as well as threatening to the quality of life for the coming generations. With the tremendous growth in economic activity across the globe placing pressure on natural and environmental resources, experts and thinkers are seeking sustainable solutions in all aspects of our lives.
Real estate development is a significant contributor to global warming as it uses about 40 per cent of the energy, and it is one of the prime contributors to extensive emission of greenhouse gases. Therefore, there is an extreme need to develop green buildings. Though green building concept is not new in India and the principles have been successfully utilised for centuries, it has become an essential instrument towards sustainability in the recent years. Sustainability in buildings is not only limited to energy conservation, but also includes efficient use of water and natural resources, impact on the neighbouring environment and working conditions for occupants. Green building design is based on ‘form follows function’ kind of designing which is associated with modern architecture and design in the 20th century. This principle rests on the concept that the shape of a building or object should be primarily based upon its intended function or purpose. This, however, should not be mistaken as a compromise in the aesthetic appeal of the design. In fact, buildings all around the world are being built with its functionality and sustainability in mind without losing out on its visual appeal.Green buildings integrate several sustainable features, such as efficient use of water, energy-efficiency, eco-friendly environment, use of renewable energy, use of recycled and recyclable materials, preserving natural topography, soil erosion and sedimentation control, effective control and building management systems and improved indoor quality for health and comfort. There are a few challenges with respect to such constructions in India. Primarily, it is due to the perception that building such projects incurs higher costs and a lot of maintenance. A certified or silver-rated green building would have incremental costs in the range of 3-5 per cent over conventional ones, whereas the cost can go up further for Gold or Platinum rated projects. However, we found out that certain developers were already considering green building initiatives in their projects such as building materials with good thermal insulating properties, high-efficiency HVAC and lighting equipment, solar water heating, water recycling plants, rain water harvesting systems and so forth. For such developers the incremental costs would be restricted to the fees for certification and consulting only. In a commercial green building, even these incremental costs could be easily recovered within a few years through energy savings, provided best operation and maintenance practices are followed.
Different technologies in each component of a building have contributed to bringing down the incremental costs for going green. Some of them are mentioned below:
Building envelopeBuilding envelope consists of roof, fenestration, glazing and the exterior walls. A thermally insulated building envelope involves using materials that reduce heat transfer by conduction, radiation and convection. It helps cut down the heat load in the building, downsising the air-conditioning equipment required to cool the spaces, and hence results in lowering of the capital costs for the project. Thermal performance of fenestration, wall and roof assembly depends on Solar Heat Gain Coefficient (SHGC) and that of glazing depends on the solar energy transmittance through the glazing (measured by U-Value). Lower the SHGC and U-Values, better are the thermal insulating properties of the wall, roof, fenestration and glass.Using insulation materials like extruded expanded polystyrene (XPS) and moulded expanded polystyrene (EPS) decrease the SHGC value of the wall and roof assembly, thereby offering good thermal insulation. But due to incremental cost, developers restrict the usage of insulation materials to roof. As a cheaper alternative to insulation materials for exterior walls, one may opt for fly ash bricks or AAC blocks instead of clay or normal concrete bricks, as they have excellent thermal insulation properties. Fly ash acts as a good insulating material and is used in both fly ash bricks as well as AAC blocks. The autoclaved aerated concrete is a versatile lightweight construction material which has low density and excellent insulation properties. The low density is achieved by the formation of air voids to produce a cellular structure.
External shading devices such as awnings, overhangs and trellises are part of the building envelope. These are installed over windows and prevent unwanted solar heat from entering a conditioned space.
Lighting systemsLighting is an essential requirement for any facility and touches the day-to-day lives of people in many ways. It accounts for 15 per cent of the total energy consumed in a developing country as against 7 to 10 per cent in developed countries.
Energy efficiency has often been viewed as a ‘resource option’ just like coal, oil or natural gas. For India, it provides additional value by preserving the resource base and mitigating the global climate change.
There has been continuous development in lighting technologies over the past 60 years to produce the best lighting products and controls for creating higher lighting quality with reduced energy consumption. However, the speed at which these technological developments have taken place has not been complemented by a corresponding pace in generating awareness about them and their availability to the end users. Also, the emergence of new secondary players has generated a lot of competition in the lighting market. These market barriers should be addressed through aggressive customer-oriented awareness programmes and demonstration projects.
Since the past decade, technology has leapfrogged given various cost-effective options to the end users.
Heating, ventilation and air-conditioning (HVAC) systemsHVAC by and large consists of centralised air-conditioning system, basement ventilation system and staircase pressurisation system. In Indian context, there is not much requirement of heating. HVAC system is one of the costliest forms of energy use in any commercial building. Some of the factors impacting the energy consumption are occupancy, hours of operations, heat load profile and seasonal ambient conditions.
Building automation and building management system (BMS)BMS includes centralised monitoring and control of systems such as lighting, HVAC and fire detection system.As the people grow more aware of the impact that green building and sustainable development can have in saving our earth from climate change, we can hope that more of such innovations will be created to help experts make that a reality. In the midst of a global ecological crisis, green building consultants and architects are relentlessly pursuing design strategies that manage to mitigate the toxic by-products of our consumption habits, while maximising our use of sustainable energy sources. Meeting these challenges means more deeply integrating green technologies like wind and solar power, natural climate controls and space-age materials in to the building processes. It is not just a way to conserve energy but also our responsibility towards our future generations. In the spirit of eco-optimism, we hope that more and more designs with a right balance of both sustainability and aesthetic innovation will be developed to assist us with the same.

Authored by—
Rumi Engineer, Head – Green Building Consultancy Services and Energy Conservation, Godrej & Boyce Mfg. Co. Ltd.

30