Energy Saving In The HVAC Industry

The Energy Statistics 2015, released by Ministry of Statistics and Programme Implementation, of Government of India, shows the estimated electricity consumption in India during 2013-14 was 882,595 GW. This has grown at the Compound Annual Growth Rate (CAGR) of 8.84 percent between 2005 and 2006 and 2013 and 2014. Out of the total consumption of electricity in 2013-14, domestic households accounted for the 22.5 percent and the commercial sector accounted for 8.72 percent. Electricity consumption in the commercial sector has increased at a much faster pace compared to other sectors during 2005-06 to 2013-14 at a CAGR of 8.82 percent. A large quantity of incremental electricity demand will come from the residential and the commercial sectors in India. Energy demands are expected to triple by 2025 and the need to implement energy efficient technology is on top of the agenda.

Role of HVAC in Energy Efficiency

According to the Indian Society of Heating, Refrigeration and Air Conditioning Engineers (ISHRAE), most commercial buildings have an Energy Performance Index (EPI) of 200 to 400 kWh/sq. m per year. Heating, Ventilating, and Air Conditioning (HVAC) equipment take a major share of electricity bills for residential, commercial and industrial applications, leading to tremendous pressure on energy sources, and ultimately impact the climate. This can be eliminated by deploying energy-efficient measures that are energy saving as well as help in cost cutting. HVAC systems comprise 40 percent of the energy consumed by buildings in India; hence, HVAC remains the primary focus area for energy savings through system upgrades and optimisation.

The International Energy Agency has indicated that energy efficiency is likely to supply more additional energy than oil through to 2030, supporting energy-efficient innovations. The HVAC industry is also eyeing a huge opportunity through energy efficiency for increased scale of business. HVAC systems, when run efficiently, can help buildings achieve a better EPI of 100 to120 kWh/sq. m per year, which makes the buildings energy efficient. Such concepts have brought a paradigm shift in HVAC technologies and trends, where majority of the changes are aimed at energy efficiency and higher energy performance. HVAC systems are now designed not only to meet energy standards but also to meet codes like Energy Conservation Building Codes (ECBC), American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) standards to achieve higher levels of Green building Leadership in Energy and Environmental Design (LEED) rating, etc.

The HVAC industry is also keen on improving its energy efficiency by continuous Research and Development (R&D) to develop products that not only use less energy but also are environment-friendly. The main offender for polluting the environment is the refrigerant used in HVAC systems. New age refrigerants like HFC-32 (R-32) enable products to be made compact, and helps curtail greenhouse gas emissions, thus guaranteeing better energy efficiency.

Redesign and right sizing of chilled water and condenser pumps, deploying high efficiency compressors, demand-based control are some of the recent improvements in existing HVAC plants to increase energy efficiency and performance effectiveness of the plant. Such measures can reduce up to 35 to 50 percent of energy consumption of a commercial HVAC system.

High efficiency chillers, variable speed drives, variable air volume boxes, and dedicated individual control are some of the popular energy efficiency techniques adopted by HVAC industry to achieve higher efficiency. The concept of using Dedicated Outdoor Ventilation (DOAS) and Demand Control Ventilation (DCV) system are now widely used in developed markets to ensure adequate ventilation and to strike a balance between human comfort and energy efficiency. DCV using CO2 Sensors, Dedicated Outdoor Air Systems (DOAS), chilled beams, night pre-cooling, thermal storage system for cooling, displacement ventilation, gas-fired chillers, and control cooling tower fans by sensing ambient wet bulb temperature are few of the important energy conservation measures on HVAC system.

Apart from installation of new energy-efficient solutions, the HVAC industry is also promoting various means and methods to effectively maintain existing systems to avoid degraded energy performance of the equipment. For example, water treatment program for tube cleaning in centrifugal chillers, to avoid formation of scale or iron deposits on the microbe site. Energy saving of 10-25 percent can be achieved if the tube cleanliness is maintained.

Other issues, with respect to centrifugal chillers, such as reduced condenser flow rate, sub-optimal refrigeration levels, oil contamination in refrigerant, leaks in the compressor, etc., when monitored and maintained effectively would result in approximately 3 to 20 percent energy savings.

On the other hand, rooftop units undergo circumstances that cause degraded energy performance, for instance, economizer failure, problems with the sensor, airflow and thermostat control, suboptimal refrigerant charge, etc., which can be checked and adjusted in order to achieve an estimated savings of 5 to 35 percent.

Additionally, it is important to note that whole building integration is one of the key factors influencing the HVAC energy efficiency. Integrated buildings pave way for higher energy efficiency.

Conscious planning and implementation of energy-efficient solutions by the HVAC industry can consistently save up to 40 percent of energy consumed in commercial, residential, and industrial buildings in India.

By 2025, total energy demanded by households and commercial buildings would account for almost 800,000 GW and with energy-efficient HVAC solutions and practices, demand can be downsized by 330,000 GW than business as usual.

This is estimated to save INR 900 billion (based on current cost of power generation), for the economy. Hence, HVAC systems play a very critical role in defining the future of energy efficiency – and are expected to bring a positive and sustainable change in the Indian buildings environment.

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