VRF & Inverter Ductable Air Conditioners

The new VRF (Variable Refrigerant Flow) method of refrigeration can be used in various air-conditioning applications. There are two basic types of VRF system — cooling or heating-only and energy recovery. Cooling or heating only can provide just cooling with the incorporation of a heat pump, cooling or heating to the space — but not both at the same time. The energy-recovery type can, however, provide cooling and heating simultaneously to different parts of the building. This feature has the potential to deliver maximum energy savings. Further, a heat-recovery system can transfer the heat extracted from those spaces requiring cooling to areas demanding heating — resulting in extremely high primary-energy ratios and low operating costs.

The market growth of VRF system is the highest in the cooling industry and has recorded a 14 per cent CAGR.

Voltas has recently introduced inverter ductable air conditioners, which is a low-cost product compared to VRF system, but equally energy efficient. The commercial spaces like showrooms, restaurants, etc. are the identified customers for this product. The refrigerant used in both of the above products (R-410a) has zero ODP and thus, are environment friendly.

Magnetic Bearing Compressor Chillers

The conventional centrifugal compressors use anti-friction sliding bearings. These bearings tend to cause friction between the moving parts with resulting high sound levels and lubrication problems. Thanks to technological advancements made, oil free magnetic bearing compressors are now available in the market. The revolutionary magnetic bearing compressors, the world’s first totally oil-free compressors, are specifically designed for the HVAC industry. The magnetic bearing, variable-speed centrifugal compressors and advanced electronic technologies, enable these compressors (60-150 TR nominal capacity range) to achieve the highest compressor efficiencies for water-cooled, evaporatively cooled and air-cooled HVAC applications.

Voltas has introduced water cooled chillers with this technology. The market is catching up, although high cost, compared to conventional chillers, is the present constraint.

Working Principle

The magnetic bearing compressors’ rotor shafts and impellers, levitate during rotation and float on a magnetic cushion. Two radial and one axial magnetic bearings are employed. Centered rotation is instantaneously self-corrected and maintained. When not powered, the rotor is supported by carbon composite, touchdown bearings designed for many years of use.

Magnetic bearing compressors have outstanding energy savings from digitally controlled, frictionless, two-stage centrifugal compression. This results in significant reductions in operating cost and also environmental emissions associated with electrical energy usage and its generation.

The magnetic bearing compressors are the quietest compressors in the industry. They operate at a sound level of 70 dBA (conversation level) with virtually no vibration. Given normal, background sound levels of plant-room, one literally cannot hear the compressor operate.

Co-generation Vapour Absorption Chillers

Co-generation is the new concept becoming popular due to increasing cost and shortage of grid power. The hot waste exhaust gases and hot water produced by DG sets or Gas Turbines (waste-heat) is used as source of energy for vapour absorption chillers. The chilled water, thus, produced in these chillers is used for air-conditioning purpose. Hence, free cooling, with negligible use of electricity is generated with this technology. With this concept, the efficiency of co-generation vapour absorption machines increases from 30 per cent to 70 per cent.

In some countries abroad, it is becoming the norm to use co-generation concept along with captive power generation plants. It is gaining popularity even in India. Voltas has a complete range of Co-generation Vapour Absorption Machines from 40 TR to 2000 TR capacity.

Geo-Thermal Air Conditioning

Geothermal air-conditioning system is today’s most energy efficient and lowest running cost air-conditioning system in the world. This system totally changes the way air-conditioning or heating of buildings is conceived at the initial design stage.

Geo-thermal air-conditioning systems are considered to be the most efficient air-conditioning systems available till date on this planet. This works on the basic principle that the temperature remains constant below earth throughout the year, irrespective of the temperature above ground. The temperature below earth is generally constant at around 20C to 27C at a depth of 5 to 20 feet below ground level, depending upon the geographical location of the place and its soil condition. Geothermal systems remove the requirement and dependence on mechanical systems such as cooling towers, heating systems, furnaces and boilers etc. This reduces long term maintenance costs. Since all other cooling systems depend on the temperature of ambient air, whose summer temperature can vary from 27C to 50C in tropical climates, the efficiencies of cooling towers and other heat removal systems are grossly affected due to the wide temperature fluctuations. This also increases the requirement of power systems and energy consumption in buildings. Geothermal systems instead, use water or refrigerant which is naturally cooled or heated by the earth, to remove heat from the heat exchangers. Geothermal air conditioning system gives very high thermal efficiency as compared to conventional systems; thus, reducing operating energy costs as well as maintenance costs. These cost reductions have been found to bring about 30 per cent to a phenomenal 60 per cent savings in running costs. Apart from this, this system also provides hot water for all requirements in the building at a negligible extra running cost, removing the need for boilers or solar water heating systems.


The technological advancement in today’s scenario is taking place by keeping in mind hazardous effect on the earth. R&D at Voltas is developing eco-friendly, energy efficient and cost-effective technologies the described in this article for domestic and export market. There is also an increased focus on using waste thermal energy to produce cooling.