A passage to Net-Zero HVAC  

Net-zero emissions signify energy-efficient HVAC solutions. Innovations like variable-speed compressors, smart thermostats, and energy recovery systems reduce energy use, emissions, and costs. Transitioning to heat pumps and renewable energy sources cuts carbon output, while low-GWP refrigerants guarantee sustainability. IoT and AI enable real-time monitoring to improve efficiency and minimising environmental impact.

The HVACR industry is the foremost one in achieving net-zero emissions. As the demand for energy-efficient solutions grows, HVAC systems are central to decarbonisation efforts, reducing greenhouse gas emissions and improving energy efficiency. The strategies for sustainable building management focus on the use of variable frequency drives zoned HVAC systems, as well as automation. HVAC systems, which consume 40-60 percent of energy, benefit from automation, with each degree reduction in temperature saving up to 3 percent of energy.

Transitioning to net zero

Manufacturing industries such as cement, steel, and aluminium contributed to India’s carbon emissions, with a reported 108 million tonnes of CO2 released in 2023. To tackle this, Mr. Rajarshi Datta, Director of Sales at Johnson Controls India, suggests implementing efficient HVAC systems that incorporate technologies like heat recovery and variable speed drives to improve operational efficiency and reduce emissions. Additionally, scalable renewable energy solutions such as heat pumps can lower energy consumption, promoting sustainability. Incentivising green innovation and emission reduction in the sector is also essential to achieving long-term environmental goals.

Mr Vivek Kumar, Product Manager- Product Management for Trane Technologies, emphasises that the HVAC sector holds the potential to reduce carbon emissions through the retrofitting of existing buildings. Many older buildings, built 15-20 years ago, often lack the advanced technology and materials available today. Carbon emissions reduction can be achieved by retrofitting these buildings with modern energy-efficient systems. He advocates a focus on public education and awareness to encourage better system design. While systems may be designed for high efficiency, they often fail to meet their intended energy capacity in real-world conditions. Increased awareness is necessary to ensure that HVAC systems are performing as designed, and regular audits can help identify areas where energy consumption can be reduced. Collaboration between various technologies, such as integrating heat pumps or heat recovery machines with traditional cooling systems, can offer additional energy savings.

Another aspect is the type of refrigerant used in HVAC systems. He stresses the importance of adhering to regulations as they evolve concerning the transition from HCFCs to HFCs. And how this transition occurred ahead of schedule in the past. A similar shift is expected with ongoing HFC regulations. Educating the market on sustainable products will help customers make better choices.

Furthermore, refrigerant management plays a vital role in reducing emissions. Proper disposal or recycling of refrigerants is crucial while replacing equipment. If refrigerants with high Global Warming Potential (GWP) get released into the atmosphere, they contribute to long-term environmental damage, remaining in the atmosphere for up to 20 years. The recycling of refrigerants is an area with significant potential for improvement.

Stakeholders have a shared responsibility for energy conservation within buildings. Mr Amit Gulwade, Chief Executive Officer at R. S. Kulkarni HVACR Consulting Engineers, emphasises that architects, designers, installers, and maintenance teams all play essential roles in reducing energy consumption. Radiant systems, for example, can reduce energy use by 30-40 percent compared to traditional air conditioning systems, providing a substantial benefit. Designers can save up to 40 percent of energy by utilising advanced technologies in building systems. Additionally, incorporating natural energy sources such as earth tunnelling, solar power, and wind energy can further decrease energy needs. However, the successful implementation of these systems lies in the hands of the installer, who must ensure that all systems are set properly.

Once the systems are in place, ongoing maintenance is crucial for sustaining energy savings. Since designers and installers are involved, it is the maintenance team’s responsibility that all components continue to function optimally. Proper maintenance ensures that the building operates with its original energy-saving design, a factor in achieving net energy savings. By involving all stakeholders in the process, from design to maintenance, sustainability goals can be achieved.

Retrofitting HVAC systems

Retrofitting buildings with radiant systems, particularly low-mass systems, is an active option as radiant cooling is not the only energy-saving solution, notes Mr Amit Gulwade. In addition to radiant cooling, Variable Frequency Drives (VFDs) impact energy efficiency. A key factor in energy savings is occupant behaviour- raising the temperature by just one degree in a conditioned area can impact energy consumption.

Additionally, technologies like heat recovery can further reduce power consumption. ASHRAE specifications, such as the reducing airflow requirements from 7.5 CFM to 5 CFM, highlight the potential for energy savings. By focusing on internal building parameters and improving energy efficiency, we can move closer to achieving net-zero energy consumption.

Low GWP refrigerant

It is logical to incorporate market-available technologies, including lower GWP (Global Warming Potential) solutions, to provide cost-effective options for customers. Mr Vivek Kumar highlights that retrofitting existing systems with these solutions can lead to slight reductions in energy efficiency. New systems with low-GWP solutions at the factory level ensure higher efficiency, helping them to reduce their Scope 1, Scope 2, and Scope 3 emissions. These reductions play a role in sustainability reporting, as companies disclose their emissions across these three scopes and outline their strategies for reducing them.

The new low-GWP refrigerants lead to an efficiency improvement of five to six times. This helps organisations lower their energy consumption, electrical expenses, and direct emissions. The environmental impact of these refrigerants is minimised because they have a short atmospheric life depending on the specific molecule used. The low-GWP refrigerants with double carbon bonds break down in the atmosphere without trapping heat, reflecting heat away from the Earth’s surface.

Technology to reduce GHG

Improving HVAC energy efficiency is crucial for reducing greenhouse gas (GHG) emissions. Mr. Vivek Kumar emphasises the advancements in compressor technologies, which have replaced the older systems using slide valves in screw compressors. These advancements allow for complete modulation by the Variable Frequency Drive (VFD), removing the need for a slide valve and thus improving overall energy efficiency while significantly reducing GHG emissions. VFDs play a key role in optimising system performance by modulating various components. In older systems, modulation was shared between a VFD and a slide valve. However, with VFDs fully handling modulation, efficiency levels can increase by 25-30 percent, as they offer a broader frequency modulation range from 12 to 60 Hertz, compared to the 35-50 Hertz range of the slide valve.

However, Mr. Vivek Kumar notes that VFDs do not always guarantee energy savings. Their effectiveness is highly dependent on the specific application. For instance, in a data centre where the load remains constant, the savings from VFDs are minimal, especially in coastal areas where the external temperature stays relatively constant throughout the year. In such cases, designing a system for optimal efficiency at full load might offer better energy savings without VFDs. It is essential to consider the application and the variability of internal and external loads when deciding whether to incorporate VFDs.

Further, he discusses the importance of Environmental Product Declaration (EPD) certification, which provides a detailed report on the carbon emissions from a product’s life cycle, from production to disposal. Obtaining an EPD certification is challenging due to the rigorous guidelines manufacturers must follow, but it ensures transparency regarding the environmental impact of a product. Opting for EPD-certified products can help organisations better track and reduce their carbon footprint, as the certification process involves third-party evaluation of emissions across the product’s entire lifecycle. By selecting EPD-certified products, companies can make more informed decisions that support their sustainability goals.

He also emphasises the role of higher-efficiency components in reducing energy consumption. For example, copper and high-efficiency heat exchangers can greatly improve energy savings. A notable innovation is Trane’s patented falling film design, which reduces refrigerant requirements by 35-40 percent compared to conventional designs. This is achieved by increasing the heat transfer area and reducing the refrigerant needed for the same heat removal, thereby improving efficiency and reducing the environmental impact. The use of low GWP (Global Warming Potential) refrigerants further contributes to energy efficiency.

Smart thermostats and controls also play a vital role in energy savings. By providing real-time monitoring and adjusting room temperatures based on comfort needs, these systems help reduce energy consumption. For example, increasing room temperatures from 23°C to 26°C can save 5-6 percent energy without compromising comfort. This reduces carbon emissions and contributes to healthier living conditions.

There is a need for continued research into natural refrigerants and energy efficiency standards. Mr. Amit Gulwade stresses the need for public awareness regarding energy use and carbon neutrality. Achieving carbon neutrality requires setting targets involving the general public in energy-saving efforts. Public awareness and engagement are critical to achieving the momentum needed for widespread adoption of sustainable practices.

Mr. Rajarshi Datta stresses the importance of system design in reducing greenhouse gas emissions. In coastal conditions, for example, using a VFD in a data centre that operates at full load year-round may not be the most efficient solution. Instead, designing systems holistically, considering the entire operational environment, and optimising energy efficiency are key to reducing GHG emissions. He emphasises that emissions reduction requires an overall system design strategy, not just isolated technological solutions.

Operational cost

HVAC systems account for 60 percent of the energy load, so reducing energy consumption directly lowers operational costs and carbon footprint, supporting net-zero goals. Building Management Systems (BMS) have evolved to ensure optimal energy efficiency by balancing CAPEX and OPEX. Post-installation, proper system maintenance is crucial for maximising return on investment, as a well-maintained system performs more efficiently throughout its life cycle, ensuring long-term cost savings and sustainability.

Mr Amit Gulwade emphasises the importance of achieving net-zero energy usage in India by setting clear targets, such as 2040 or 2035. He advocates for implementing energy consumption limits in building approvals, ensuring that buildings do not exceed 0.8 energy usage per capita. A strategic, phased approach is essential for sustainability.

In conclusion

HVAC systems are key to decarbonisation by cutting greenhouse gas emissions and improving efficiency. There is a burgeoning demand for energy-saving solutions. Advances like variable-speed compressors, smart thermostats, and energy recovery-ventilation systems reduce energy consumption and costs. Electrification through heat pumps helps minimise carbon output, while low-GWP, eco-friendly refrigerants support sustainable cooling and storage. Implementing building management systems (BMS) leads to energy efficiency improvements of 10-15 percent, reducing energy consumption and carbon emissions, and contributing to achieving net-zero goals.

Furthermore, IoT and AI technologies enable real-time monitoring and optimisation, improving system efficiency in achieving net-zero emissions through energy efficiency.  Lastly, collaborative efforts between governments, regulatory bodies, and the HVACR industry to achieve global sustainability will create a pathway to net-zero emissions in future.

===============

Mr. Rajarshi Datta, Director, Sales, Johnson Controls India

To reduce emissions and operational efficiencies, efficient HVAC systems using technologies like heat recovery and variable speed drives can be implemented.

Mr. Vivek Kumar, Product Manager- Product Management, Trane Technologies

Releasing high-GWP refrigerants harms the environment for up to 20 years, so, recycling refrigerants has the potential for improvement.

Mr. Amit Gulwade, Chief Executive Officer, R. S. Kulkarni HVACR Consulting Engineers

Solar or wind energy can also reduce energy consumption and, the responsibility of implementing these systems falls on the installer.

Mihir Sanghavi, Managing Partner, Auro Engineering

Achieving net-zero emissions requires a mindset change and a collaborative approach across various stakeholders.