Small Is Cool

The Indian AC market is moving towards MicroGrooved, smaller diameter copper tube Heat Exchangers, says Shankar Sapaliga, Sr. Advisor- HVAC, ICA India, writng in Thermal Control magazine

The Kigali Amendment to the Montreal Protocol for phase down of Hydro fluorocarbons (HFC) has for the first time, recognized the linkages between refrigerant transition and energy efficiency of air-conditioning equipment within the realm of the Protocol.

India is among the largest and fastest growing markets globally for room air conditioners (RACs) with about six million units sold in 2019. Increased infrastructural development, urbanization, higher standards of living and rising disposable income have all contributed to the heightened demand for air-conditioning.

The Bureau of Energy Efficiency (BEE) had introduced energy efficiency norms for room air conditioners which has resulted in reduction of energy consumption in the residential sector. Star-rated air conditioners have proven to be a total success in the Indian market due to the Government’s mandatory policy.

India is one of the first countries in the world to develop a comprehensive Cooling Action plan which has a long-term vision to address the cooling requirement across sectors and lists out actions which can help reduce the cooling demand.  India Cooling Action Plan was released by the Union Minister of Environment, Forests and Climate Change, Dr. Harsh Vardhan, during March 2019. The plan is aimed at reducing emissions and providing thermal comfort to citizens. The India Cooling Action Plan encourages boosting the domestic air conditioning industry through adaption of latest technology.

International Copper Association India (ICA India) is actively supporting the air conditioning industry towards phase down of potential Global Warming refrigerants, develop energy efficient products, and reduction in material content. One of the major steps by ICA India was to promote smaller diameter MicroGroove copper tube for heat exchanges for the air conditioners. The smaller diameter, inner grooved, copper tube heat exchanger not only has better heat transfer coefficient (HTC) than the larger diameter tubes, but is also more energy efficient and consumes less material, thereby making it more cost effective. 

Smaller diameter copper tubes (MicroGroove) provide higher strength, while keeping the heat exchanger’s weight down and allows for lower refrigerant volume, while saving on material costs. As a refrigerant, CO2 has a very high vapor density, which means that it works very well with smaller diameter tubes because of the minimal pressure drop. Typical operating pressures are 60 bars (i.e., 6 MPa or 870 psi) on the evaporator side, and 130 bars (i.e., 13 MPa or 1885 psi) on the condenser/gas-cooler side

ICA India has collaborated with several Indian OEMs to optimize their existing models with Microgroove heat exchangers. These heat exchangers have proved that there is reduction in material (up to 15%), and refrigerant charge (up to 15%) in the system besides improvement in performance and energy efficiency (SEER). As a result, MicroGroove copper tubes heat exchangers are increasingly being used in air conditioning and refrigeration applications in South Asia. In India, the majority of manufacturers have started using 5 mm MicroGroove copper tube for heat exchangers for room air conditioners.

The Indian market has picked up usage of MicroGroove copper tube heat exchangers, and it is continuing to grow in the Indian HVAC industry. It is true that a decade ago, larger-diameter copper tubes began to lose market share to aluminum.  Although a low point was reached in 2014, the corrosion resistance of copper prevailed, and copper heat exchangers are now recapturing market share. The trend back toward copper has been dramatic in the last five years, as end users of aluminum microchannel experienced many cases of failure and leakage of refrigerant to the atmosphere leading to potential global warming. MicroGroove copper has emerged as an easy-to-maintain, reliable and durable option, well suited for the tropical climate of India.

Truly, MicroGroove is a global phenomenon. The coils are made around the world, in China, Korea, Vietnam, Japan and India; in several EU countries; and in the United States, Canada and Mexico. It is a breakthrough, “game-changing technology” in every sense of that phrase; and it is paving the way to more eco-friendly solutions for human comfort and the cold chain.

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