The “less is more” principle popularized by American inventor R. Buckminster Fuller
is especially apt with respect to coil designs for air-conditioning and refrigeration
appliances. Demands to increase energy efficiency and lower material costs forces
manufacturers to reconsider their coil designs. Also, concerns about the atmosphere
are driving manufacturers to reduce refrigerant volumes and minimize the ozone depletion
potential (ODP) and global warming potential (GWP) of refrigerants.
Copper Tubes are the HVAC Industry Standard for a reason
Condenser and evaporator coils with round copper tubes and aluminum fin have been
a winning combination in the HVAC industry for many years. Manufacturers appreciate
the assembly advantages provided by these components, and technicians find it easy
to join and repair copper tubing in the field. More importantly, this well established
technology has a proven record of durability and a high level of customer satisfaction.
Demands for lower costing, energy efficient, environmentally friendly alternatives
have moved the copper tube industry toward tubing that is smaller in diameter. The
advantages of smaller tubes include higher heat transfer, less refrigerant and smaller
Overall Benefits of Economical, Eco-friendly MicroGroove Copper
Demands for reduced raw materials costs and the use of environmentally friendlier
refrigerants have been the impetus for heat exchanger designs that are based on
smaller diameter copper tubes. Reducing the tube diameter achieves weight and material
cost reductions, increases compatibility with new refrigerants, and increases energy
efficiency, all without compromising quality. In addition, the advantages of using
copper — familiar manufacturing processes, recyclability, sustainability, durability
and corrosion resistance — are maintained. Energy efficiency and reduced overall
system size can be achieved at a lower material cost with smaller diameter tubes.
Smaller tubes result in reduced usage of tube materials, fin materials and refrigerants,
contributing to overall reduction in system cost.
MicroGroove Copper Tubes Equal Increased Heat Transfer
The goal in residential and commercial air conditioner design and manufacture is
to reduce cost and increase energy efficiency. Copper is a means for achieving that
goal. Smaller diameter tubes allow for higher heat transfer efficiency because the
refrigerant flow is closer to the tube wall than it is in larger diameter tubes.
Because smaller diameter tubes can be designed with a higher “heat transfer coefficient,”
they can achieve the same performance as larger diameter tubes with less tube and
MicroGroove Copper Tubes Work Well Under High Pressure
The inherent strength of smaller diameter tubes is an advantage, especially in light
of the higher pressure requirements of modern refrigerants. Although the number
of tubes in an evaporator or condenser is likely to increase with smaller diameter
tubes, potential increases in weight can be offset by more compact coils resulting
from higher heat transfer efficiency.
Fin Designs for MicroGroove Copper Tubes
Fins can be made from aluminum or copper. In either case, less fin material is required
for coils with small diameter copper tubes compared to larger diameter tubes. Since
less fin material is required, copper fins are an attractive alternative fin material,
providing advantages with regard to corrosion resistance.
Manufacturing MicroGroove Copper Tubes
Copper tubes are produced by a number of different processes, but they all allow
efficient and economical production of sizes from very large to very small diameters.
For air conditioning and refrigeration applications, the tubes are provided with
inner surface enhancements to increase the surface area. Rifling or grooving the
inside of the tube helps to mix the refrigerant, homogenizes
The refrigerant temperature across any tube section and improves heat transfer performance.
Reducing the diameter of the tube contributes to the mixing or refrigerant turbulence,
further improving heat transfer. Existing air-conditioner coils comprised of round
copper tubes and aluminum fins (CTAF coils) typically are mechanically assembled
using tube expansion. MicroGroove copper tubes also can be assembled using tube
expansion with minor modifications to the expansion tube.
2013 Air Con Industry Report
Indian room air conditioners market was estimated to be 3.5 mn units in 2013 with
a penetration of 3% in the Indian market. This market is expected to grow by 15%
annually in next few years mainly due to raising income levels, urbanisation, expansion
of modern retail and exclusive company’s outlets. Over the past few years, rural
market has registered impressive growth and is expected to grow by CAGR of 31% from
2006 to 2016 whereas urban market is expected to grow by CAGR 12% during the same
period. Preference for quitter RACs, aesthetic looks and energy efficiency has resulted
in increasing share of split RACs with a market share of 83% in 2013.
Even though the concept of smaller diameter copper tube in heat exchanger is not
new to the Indian industry, OEMs have not yet adopted the concept commercially in
production. ICA has been one of the torch bearer for the 5 mm Microgroove Copper
Tube heat exchangers globally and have worked extensively on the technology with
various universities, consultants and OEM. This has given them access to vast literature
and understanding on the topic. The role of ICAI is to introduce this new technology
to various OEMs in India.
Standard & Labelling in Room Air Conditioners Program
India is presently the sixth-greatest electricity generating country and accounts
for about 4% of the world’s total annual electricity generation. India is also currently
ranked sixth in annual electricity consumption, accounting for about 3.5% of the
world’s total annual electricity consumption. However, per capita consumption of
electricity in India was 673 KWh in 2011 which is just 23% of the world’s average
per capita consumption of electricity.