The need of the hour: Energy-efficient buildings
Real Estate

The need of the hour: Energy-efficient buildings

Buildings consume over 30 per cent of India’s total electricity. So, it stands to reason that the process of certifying a building as green prioritises energy-efficiency. The hallmark of energy-efficiency is the net-zero energy building concept, implying buildings that are designed to operate...

Buildings consume over 30 per cent of India’s total electricity. So, it stands to reason that the process of certifying a building as green prioritises energy-efficiency. The hallmark of energy-efficiency is the net-zero energy building concept, implying buildings that are designed to operate with a minimal energy load and meet their energy needs through renewable energy sources. Improving energy-efficiency can reduce the energy consumed annually by about 25 to 30 per cent with respect to the national baseline and, thus, reduce the cost of energy by at least 30 per cent, points out Sampath Kumar Kabothu, Senior Counsellor, Confederation of Indian Industry, CII Sohrabji Godrej Green Business Centre. “Besides, harnessing renewable energy can give a building a reliable source of power supply if it is combined with energy storage devices. From the perspective of occupants, net-zero energy buildings offer increased daylighting and better thermal comfort.”In prescribing standards that top the national benchmark, even the ECBC 2017, the latest building energy code, is prioritising energy-efficiency. The ECBC 2017 sets the energy performance index at 180kWh/m2/year as against the 100-150kWh/m2/year prevailing benchmark.Load-minimising designIn fact, energy-efficiency starts from design. The right design can lower the energy load significantly. “If the architect’s mandate is to design a commercial building that uses energy efficiently, the process will begin by studying the electrical load and focusing on areas that can be impacted the most, such as air-conditioning or daylighting,” says Amit Khanna, Design Principal, AKDA. “If the building has a large vertical surface area, the discussion will be around minimising heat gain through the envelope,” he further explains. “However, if the building has a large roof area, the focus will be on insulating the terrace and creating a microclimate to reduce roof temperatures.” The ways to achieve energy efficiency are similar in a residential building but here, Khanna says, “the focus shifts to choosing materials that mitigate heat transfer or buy the building deeply shaded spaces.”Energy-saving façades and fenestrationsChoosing heat-resistant façade materials and highly insulated windows and doors goes a long way in helping to make the building envelope more energy-efficient. For instance, the thermal insulation provided by window, door and façade systems from Schueco save on energy costs while creating a visual accent. “By means of expanded insulation zones, a continuous centre gasket, a special glazing rebate, Shueco’s HI (highly insulated) and SI (super insulated) series achieve maximum air tightness and Uf values of 0.7-1.9 W/m²K,” says Pratik Doshi, National Manager, Façade Business, Shueco. “With appropriate triple glazing or a leaf-enclosing infill panel, Ucw values less than 1.‎0 W/m²K can be achieved.”The key is to have the right product for the application. For example, Doshi recommends AWS 90.SI⁺GREEN for a passive house-certified system delivering a frame with Uf value (≥) 0.7 W/(m²•K). The headquarters of the Rural Electrification Corporation in Gurugram uses a Schueco UCC 65 S G (unitised façade), ASS 50 (sliding door) and ADS 65 (openable door). Together, Schueco products at the project achieve U-values ranging from 1.2 W/m2k to 1.75 W/m2K. Villa-S in Ahmedabad uses Schueco ASE 80, a highly insulated lift and slide solution delivering U-values as low as 0.99 W/m2K. Schueco ASE 60/80 has also been used in many private residences across India.Cutting down HVAC loadsHVAC systems account for more than half of the total electricity consumed in commercial or residential buildings, especially in summer, according to the Bureau of Energy Efficiency. Therefore, there is a need to prioritise solutions that can help reduce this load.“Integrating the HVAC with an automation system incorporating occupancy sensors and zonal controls can deliver 15-20 per cent savings on energy through precise control,” reckons Amitabha Sur, Director, Operations, Aircon India Incorporated. “Recently, we upgraded a conventional air-conditioning system in a hospital using modern devices and controls for a chilled water system, and over a period of one year’s operation we could see such energy savings.”Beyond energy savings, an intelligent HVAC ensures better indoor comfort and ease of use through pre-commands.The advantages of integrating an HVAC system with an automation system far exceed the challenges of power quality, for starters, points out Sur. “Electronic hazards such as erratic voltages and surges can damage the sensors installed to monitor and control the HVAC system. Of course, protective devices exist to override this challenge. Dampness and dust deposits on power circuit boards are another challenge, especially in coastal and humid areas.”Digital energy managementA digital energy management solution plays a key role in achieving energy-efficiency. Digital technologies that help manage energy perform multiple functions. They collect data from energy metering systems and various sensors installed in the building. They analyse this data and present it to help pinpoint trends, reporting and further analytics. They also control electrical installations such as lighting or HVAC air-handling units or chiller plants to optimise the use of energy and enable the user to save peak power and stay within the maximum demand limits.For instance, ABBs Ability™ Energy Manager can save up to 20 per cent of the energy bill through scheduling lighting in temporarily occupied rooms and automatic presence detection with brightness-based control. Creating a time schedule for cooling individual rooms helps drive up to 10 per cent energy savings, while using presence detection to cool those individual rooms helps drive up to 25 per cent energy. Using low energy lighting (LED) can cut energy costs anywhere between 40 and 90 per cent. ABBs Ability Building Manager tool can save up to 25 per cent of the energy used.“The energy savings from implementing both these solutions in Disha (see box for more details), ABB’s corporate office, range between 20 and 25 per cent, and peak at 30 per cent,” shares Kiran Dutt, President, Electrification Business, ABB India. A digital energy management solution in Dr LH Hiranandani Hospital is designed to reduce the energy consumed by the HVAC system by 20 per cent. The solution involved converting the existing constant flow system to a demand-based variable flow system, by replacing three-way chilled water valves with two-way valves and installing variable frequency drives (VFD on the chilled water pumps with a complete chiller plant manager. Essentially, the smart VFD control has driven energy savings in the air-handling unit and dynamic chilled water balancing has reduced the energy consumed by the chilled water pumps while a portal allows the installation to be remotely monitored.“As a result of such energy-efficient measures, we can save construction costs up to nearly 5 per cent, which can be increased once the adoption is on a larger scale,” says Prashanth N, Director - Projects, Hiranandani Group. “Further, we will leverage technologies like artificial intelligence [AI] and machine learning [ML] to constantly monitor, periodically improvise and effectively rectify errors. As a pilot project, we are installing a similar energy conservation system in our eco-friendly hotels like Rodas – An Ecotel and Meluha – The Fern. We opted for an operating cost OPEX (ESCO) model to explore newer technologies and their effectiveness without [an upfront] investment.”For his part, Anshuman Magazine, Chairman & CEO - India, Southeast Asia, Middle East & Africa, CBRE, expects enabling technologies to monitor and enhance the energy performance of buildings to see greater adoption in future.Tapping renewable energyIf a building is expected to generate some or all of the energy it will consume, Khanna points out that while “solar panels are the most common and practicable renewable energy source for a residential or commercial building, it is up to the architect to integrate the solar panels into the design of the building rather than treat them as an add-on to the terrace, and to ensure that the electrical systems are wired to allow the solar panels to be integrated seamlessly.” Further, “solar panels work best when combined with a net metering system that feeds electricity back into the grid,” he continues. “Onsite storage or time-shifting power backup through battery packs is an alternative, but still marginally inefficient.” At Hiranandani Fortune City, the 370,000 units of solar power generated by a 383.91 kWp rooftop solar system on New Castle, a commercial building, is used for lifts and lighting in common areas and water pumps. The excess power generated during the day is fed back to the grid through a net metering arrangement. In future, this will be expanded by an additional 80 kWp rooftop solar system to power common areas of the main receiving substation. “Through this system, we’ve saved 526,304.1 kg of Co2 emissions, the equivalent of planting 15,709 trees,” shares Prashanth.Whereas some buildings can install renewable energy sources onsite to meet some or all of their needs, where this is impractical, buildings must resort to importing renewable energy from offsite to achieve the net-zero energy building criteria. Essentially, a building that fully offsets the use of grid energy through renewable energy sources adheres to the net-zero energy concept.“Our operational portfolio procures over 60 per cent of our annual energy through renewable energy and we’re always looking for opportunities to increase procurement from renewable sources,” says Harleen Oberoi, SVP & Head - Project Management, Tata Realty & Infrastructure. “We employ various strategies including onsite rooftop solar panels and solar light fittings for outdoor areas, as well as offsite wind and solar plants where we have invested and signed long-term PPAs. Our flagship asset, Ramanujan Intellion Park, Chennai, is the first IFC EDGE Zero Carbon certified campus in India with over 98 per cent energy procured through renewable sources. Our operational properties are IFC EDGE Advanced certified, meaning that our buildings use at least 40 per cent less energy than typical buildings.”An existing building can also be retrofitted to become more energy-efficient by using only renewable energy. For instance, the CII-Godrej Green Building Council office underwent deep HVAC retrofits, the deployment of energy-efficiency measures and the installation of bifacial solar PV modules to meet all its energy requirements through renewable energy and move towards becoming a net-zero energy building. The right productsTo maximise energy efficiency, it is vital to select the right products and solutions. One way to evaluate products is to determine the LEED credit points related to Energy and Atmosphere that the products in question can contribute to.  For instance, ABB products and solutions can contribute to six credit points under Enhanced Commissioning, 18 credit points under Optimised Energy Performance, and one credit point each under Advanced Energy Metering and Enhanced Refrigerant Management respectively.Tata Realty & Infrastructure’s energy-efficient buildings feature products like EC motors, highly efficient series counterflow water-cooled chillers, lift regeneration devices, sensor-based efficient LED fittings, etc.The green building premiumAs the demand for energy as well as energy prices grow globally, and government regulations tighten, ‘green’ is sure to grow as a concept.In fact, a recent APAC report by CBRE that examines whether the green premium exists indicates that reducing energy consumption and carbon emissions is the environmental, social and corporate governance (ESG) consideration most likely to impact property value.“Investors and occupiers are most often willing to pay a premium for buildings with onsite renewable energy generation and/or smart technology to monitor and adjust energy usage,” says Magazine. “This is evident in India too, wherein major cities like Delhi-NCR, Mumbai, Bengaluru, Pune, Chennai and Kolkata boast a 34 per cent certified stock of green buildings. In 2022, the certified green buildings organised market size across the top six cities in India was about 270 million sq ft, up by about 46 per cent since 2018.”Indeed, during the Net Zero Buildings Week (observed globally from June 12 to 16), India was declared the country with the most LEED Zero green building projects. A complement to LEED certification, LEED Zero recognises projects that have reached net zero or net positive status in the categories of carbon, energy, water or waste. India has 73 LEED Zero certified projects, close to half of about 150 LEED Zero certifications, outperforming the US and China with 47 (30 per cent) and 15 (10 per cent) certifications respectively. “India’s leadership position in LEED Zero projects reflects its commitment to sustainability and the adoption of innovative green building practices,” says Gopalakrishnan Padmanabhan, Managing Director, Southeast Asia and Middle East, Green Business Certification Inc. (GBCI) India.In India, DLF has the most certifications (45), followed by the ITC Group (15). Haryana and Tamil Nadu lead the way in certifications.What India now needs is for “the effects of strategic ESG policies in the real-estate sector to be monitored and calibrated gradually to build more sustainable structures and for developers to look beyond profits and take action on a plan to protect the environment,” says Magazine.We might add, developers that that are “focused on providing sustainable campuses to clients and bringing down the carbon footprint”, despite the fact that “the cost savings from renewable sources are reducing by the day due to increased capital and operational costs”, to quote Oberoi. How can existing buildings be made energy-efficient? When ABB sought to create a new corporate building within its Peenya campus in Bengaluru, named Disha, it decided to upcycle and repurpose an existing building instead of constructing anew. In using an existing building, “we significantly reduced the environmental impact that a greenfield project of this scale would have generated,” explains Kiran Dutt, President, Electrification Business, ABB India. “Sustainability is a key part of our company’s purpose and of the value we create for our customers, employees and all our stakeholders,” continues Dutt. To take forward that thread, and minimise the carbon footprint of the corporate building, ABB decided to “demonstrate what can be done to make buildings more efficient through the deployment of integrated digital building automation and electrical technology.” Thus, more than 5,000 ABB products were integrated within Disha, and are being monitored and controlled with the help of ABB’s Aspect IBMS (Integrated Building Management Solutions) technology, a unified platform to remotely monitor and control multiple points enabled with sensors from lighting and HVAC to security. This platform has been combined with a cloud-based SaaS solution, ABB Ability™ Building Ecosystem with Active Energy and Asset Manager, and an AI-enabled vehicle management and parking system. Features and functionalities built into the Ability platform are housed in the air circuit breakers. The various energy-saving functionalities built into Disha include AHU scheduling, static pressure VFD modulation, Co2-based VFD modulation, occupant sensing and monitoring, schedulers and calendar events, lux level controls, ambient temperature tuning, automated VRF controlling and duty standby controls. With all this, Disha has achieved around 30 per cent saving on the cost of energy, reckons Dutt. Incidentally, all the energy Disha uses comes from renewable sources and, thus, the building adheres to the net-zero operational carbon concept. “Ideally, we would have preferred to establish our own renewable energy sources but the existing rooftop was occupied by other utility installations,” explains Dutt. “So we are consuming grid energy from renewable sources.” Disha was designed to meet the LEED Gold criteria. So, in what other ways is Disha green? Intelligent fixtures reduce the building’s load on potable water by 55 per cent. With 98 per cent of its waste being recycled, Disha has almost reached its target of zero waste to landfill. The 15-acre campus has a green cover of about 30 per cent, which was preserved during the construction process. Nearly 120 trees, some more than 60 years old, were saved from being felled. A special recycled plastic mix of 6,000 kg, equivalent to 150,000 one-litre plastic bottles, was used to construct the footpath.

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