With increasing urbanisation and usage of ACs, the efficiency of air-conditioning equipment becomes a requisite.

In the wake of rapid urbanisation, increasing population and scarcity of space, the construction of high-rise buildings in both residential and commercial segment has seen a boom since the last few years. However, making a very tall, high-density building ‘sustainable and green’ involves a plethora of challenges which includes maintaining high indoor air quality, ensuring thermal comfort and making it overall energy efficient.

1Energy consumption for a commercial high-rise building
Partha Sen, General Manager (Department Head – Marketing), Johnson Controls-Hitachi Air Conditioning India Ltd, says, “The heating, ventilation and air conditioning (HVAC) system of any building comprises of a substantial part of its overall energy footprint. This number becomes as high as 40 per cent of the total energy consumption for a commercial high-rise building. All this coupled with the added challenge of ensuring a continuous supply of fresh air and catering to the idea of comfort of hundreds of individuals, all within a building’s envelope, adds to the level of difficulty in creating sustainable and cost-effective high-rise building.”

He adds, “While energy efficiency, environment conservation, green building and smart cities have already become the new buzz words in the global scenario since a long time, the Indian HVAC & R industry elements of which contribute to almost 40 per cent of the total energy consumption in the building, has also started working towards incorporating these into its designs and products.”

2Frequency inverter – the best energy saving solution
Harvinder Bhatia, Managing Director, BITZER India, informs, “BITZER offers an extensive portfolio of energy-efficient products. A great possibility to reduce energy costs offered by the company is frequency inverter-driven solutions. Like this, users can smoothly adjust a compressor’s capacity to meet the actual requirements and save energy. If the motor is controlled by a frequency inverter, the frequency of the starting current and thus the speed of the motor can be adapted to the required compressor power. If less energy is required at certain points in the process, the frequency inverter can adjust the electrical frequency and slow the motor down. This ensures that the engine consumes only the energy that the process needs right now.”

VARIPACK frequency inverters
BITZER’s external VARIPACK frequency inverters offer these advantages and can be intuitively commissioned without any specific knowledge about inverters. They adjust to ideally suit the system’s current cooling requirements, reducing both energy consumption and running costs. The precise coordination of compressor and frequency inverter saves additional energy there by increasing compressor efficiency in full and part-load.

3Air conditioning emerges as one of the key drivers
Anuraaga Chandra, Head – Cooling & Heating Sales, Danfoss India Region, says, “Presently, air conditioning is an integral element of human comfort in an indoor setting. With increasing urbanisation and usage of ACs, the efficiency of air-conditioning equipment becomes a crucial factor and this is largely dependent on how the equipment responds to variations in indoor temperature and the outdoor (ambient) temperature.”
He adds, “While the indoor temperature loads change constantly (where the heat is taken out from), the ambient temperature has daily as well as seasonal variations (where we dissipate the heat that is taken out). To match the continuous load variations, the air conditioning system should be able to adjust to its cooling capacity.”

According to Bureau of Energy Efficiency, it is useful to educate the consumers on pre-setting an optimum indoor air temperature which is healthier, comfortable and also saves cost, energy besides being beneficial to the environment.

4A cost-effective operating strategy to reduce energy consumption
Manish Asawa, Managing Director, Asawa Insulation Pvt Ltd, says, “If you set the thermostat at 18C it will not mean that the air conditioner will cool the room faster than if set at 25C. The thermostat just checks the temperature of the air inside the room and stops the compressor when the temperature reaches the desired level. This means that the compressor will work longer if the temperature is set to a lower level, i.e. it will work more and use more electricity if temperature is set to 18C than if it is set to 25C. This is because it will take less time for air to reach to 25C than 18C as the compressor is working with the same power or wattage.”

5Building insulation: reduces strain on air conditioning systems
Mahesh Kumar, Sr. Manager – Marketing & HVAC Systems, U.P.Twiga Fiberglass Ltd, says, “Efficient air conditioning system is a system of controlling the humidity and temperature as per desired value in a building or vehicle for human comfort at minimum cost. Usually, heating ventilation and air conditioning systems consume nearly 50 per cent to 60 per cent of the total power consumption in any building and thus, offer huge potential and challenge at the same time to reduce the energy consumption by employing various innovative system designs.”

There are different ways to optimise the energy consumption like sealing the duct joints and containing air leakage properly. For optimising the system, heat load calculation should be done correctly otherwise equipment with higher tonnage capacity will be installed that will consume more energy, but it has been analysed that half of the energy we use to heat or cool can simply leak out without insulation. Therefore, maximum energy loss can be reduced by using proper insulation material for enveloping the building, air-conditioning ducts and hot or chilled water pipes etc.

Insulated supply ducts deliver conditioned air into a building saving energy. The intent of energy efficiency codes, as related to duct insulation and sealing, is to keep mechanically warmed or cooled air as close to a constant value or desired temperature. If reduced heat transfer through insulated ducts is accounted for in the heating, ventilating, and air conditioning (HVAC) load calculations, it may even be possible to reduce the size of HVAC equipment.

Kumar says, “Building insulation also plays an important role to reducing strain on air conditioning systems. During summer season, infiltration of outdoor heat into the building can cause the air conditioner to work harder, resulting in higher electricity bill. So, if the building is properly insulated, then it can prevent heat to penetrate inside the building that will reduce the load on air conditioning systems and result into saving of energy and lowers the electricity bill.”

Most advanced, energy-efficient AC and thermal insulation solutions

SET-FREE Kyosho Series and Front Flow Series
In VRF system range, which addresses the architects and HVAC consultants, Hitachi has developed a wide range of air-conditioning system (up to 54HP). Sen from Hitachi, opines, “Our SET-FREE Kyosho Series (Top Flow) and Front Flow Series, offer a holistic approach to air conditioning in modern offices -units that are capable of simultaneously cooling and heating, adapting to the different seasons and various temperature requirements of rooms. In addition to this, we have also introduced SET FREE-Sigma Series this year.” Named after the mathematical symbol “?” which stands for the combined strengths of Johnson Controls and Hitachi VRF technologies, this series has been designed globally for Indian climate and customers. It offers higher energy efficiency, engineered aesthetics, enhanced strengths, compact design, compact cooling and heating. Thus, with least energy wastage, maximal capacity in minimalistic floor space, SET FREE-Sigma Series gives energy efficient performance combined with premium looks.

Centrifugal Chiller Series with R134A refrigerant
For commercial and industrial requirements, Hitachi’s screw (air and water) and Centrifugal Chiller Series with R134A refrigerant offers most energy efficient cooling solutions. Its impressive performance coupled with precise and continuous capacity control technology, user friendly LCD touch panel and high performance compressor, provides cooling with low noise and low vibrations which is ideal for industrial and commercial purposes.

Sen states, “With our three pronged focused strategy of quality, innovation and advance technology keeps us ahead of competition and also helps us in delivering products that not only meet but are beyond the expectations of its end users.”

BITZER CSV series
Bhatia from BITZER says, “The motor technology and electronics of the BITZER CSV series is optimised for air-conditioning systems: The robust engineering of the screw compressor in combination with active monitoring of the application limits optimises the highest operational standard in reliability whilst also providing system operators with an overview of all relevant operating parameters.”

Compact screw compressors with CSV technology are an intelligent form of forward-thinking. They can be used to build highly efficient liquid chillers and heat pumps which fulfil the most diverse kinds of future legal requirements – all over the world. At the same time, these CSV compact screw compressors work with extreme energy efficiency at both full-load and part-load. They can also be quickly and precisely adjusted to changing system requirements. This is carried out by the infinite speed control using the integrated frequency inverter. Two housing sizes are available with five displacement volumes and two Vi ranges: CSVH for air-cooled liquid chillers with higher condensing temperatures and for heat pump operation and CSVW for water-cooled liquid chillers and air-cooled liquid chillers with moderate condensing temperatures.

Fixed speed systems
In a typical air-conditioning system, fixed speed systems are designed to match the peak load of the system, where the system runs at part load capacity most of the time. The difference in part and peak load capacity during the running of the plant directly results in higher energy usage which can be easily addressed by designing it efficiently.

Inverter technology
Energy-efficient capacity modulation is the ideal way to match cooling capacity to cooling demand thereby matching these application requirements. The golden rule that applies here is to match the equipment capacity to the temperature load variation with minimum possible response time. Chandra from Danfoss, says, “With the rapidly changing HVAC market, inverter technology is the most energy efficient technology and is currently revolutionising the way air conditioning systems are being designed and built to meet climate control needs around the world. Therefore, understandably, variable-speed technology gains a competitive advantage.”

Inverter technology ensures better power supply quality, system diagnostics, humidity control, energy savings, accurate temperature control, less noise, process safety and greater comfort.
Danfoss’ most advanced solutions that use various modulation technologies are the multi scroll chiller and the turbocor magnetic oil free compressors which find application in the below areas:

• In comfort cooling, where there exists a need for a stable and accurate temperature and humidity control in areas such as hospitals, IT and telecoms, process cooling.
• In applications such as schools, restaurants and office buildings where it is important that the cooling system can adapt to wide daily shifts in load.
• In process applications such as fermentation, growing tunnels and industrial processes, accurate temperature settings are required to secure production quality.

Choosing the best energy-saving air duct plays a crucial role
The central air conditioning system, which occupies 50 per cent of the total electric energy consumption, is one of the indispensable modern architecture facilities. The central air conditioning system is made up of host equipment and terminal equipment. The electric energy gets converted to wind energy by host equipment; this wind energy is circulated to every air conditioning area by huge ducting systems. Therefore, not only considering energy-saving of host equipment is important, but choosing the best energy-saving air duct is also equally important while designing central air conditioning system. Manish from Asawa says, ” A proper selection of high quality ducting system will bring added energy-saving effect. This effective energy saving can be achieved by using an excellent insulation performance material and no leakage ducting systems.”

For most of the ducting system the most efficient solution would be a system where there is no air leakage as almost 40 per cent of energy efficiency is lost due to air leaks from the systems. To overcome the possibility of leakages in a centralised ducting unit, AIPL has developed a new type of ducting system called as “SMART Pre- Insulated Ducting System” using which one can achieve almost zero leakages.

SMART PIR Ducting system
SMART PIR Ducting system saves electricity with minimum of 10 per cent to 30 per cent per annum, whereas GI life span decreases because of leakage from joints due to corrosion. In fact, traditional air duct adopts socket joint, so wind leakage is inevitable and their actual energy consumption is far more than that of conventional GI Ducting system. Also because of contraction and expansion of GI ducts, corrosion occur which results in air leakages and more energy is therefore required to attain same temperature over a period of time. SMART PIR Ducting Systems are eco friendly, acoustic, moisture resistant, have negligible water absorption, anti-fungal or microbial, are fire retardant, have higher density, fast track installation possible, corrosion resistant, anti-rodent etc and more than 95 per cent closed cell technology which has a long life span with low maintenance.

Glasswool insulation – eco-friendly material for many applications
Glasswool insulation is considered as one of the best materials worldwide because of its application temperature range and varied usages in different applications such as HVAC, building, transport etc. If one see the thermal parameter of Glasswool, its thermal conductivity value which is commonly known as K-value (ability of the material which allows the heat to flow), is lower than other foam-based insulations. With low thermal conductivity value, it offers better R-value. Glasswool comes in low densities too, so even high thickness material (higher R-value) can be easily wrapped over ducts which are not possible with other insulations. There are some materials whose conductivity is quite low in the beginning but gradually increases, so using such insulation also are not worthwhile because for better thermal properties, insulation should have stable thermal parameters. Along with good thermal properties, Glasswool has very good acoustic properties too. It is also the most fire-safe material (non-combustible) and meets almost all fire safety standards.

Kumar from U.P. Twiga says, “Glasswool is one of the green products certified by Indian Green Building Council, Singapore Green Building, GRIHA rated in Criteria 14, 27 and 29 and SVAGRIHA in criterion 5 and FM approved product. Glasswool is most widely renowned eco-friendly material for many applications which is also cost-effective and energy-efficient at the same time.”

Hitachi’s screw (air and water) and Centrifugal Chiller Series with R134A refrigerant offer most energy-efficient cooling solutions.
Partha Sen, General Manager (Department Head – Marketing), Johnson Controls-Hitachi Air Conditioning India Ltd

A great possibility to reduce energy costs offered by BITZER is frequency inverter-driven solutions.
Harvinder Bhatia, Managing Director, BITZER India

Inverter technology is currently revolutionising the way AC systems are being designed and built to meet climate control needs.
Anuraaga Chandra, Head – Cooling & Heating Sales, Danfoss India Region

SMART PIR Ducting system saves electricity with minimum of 10 per cent to 30 per cent per annum, whereas GI life span decreases because of leakage from joints due to corrosion.
Manish Asawa, Managing Director, Asawa Insulation Pvt Ltd

Glasswool is a widely renowned eco-friendly material for many applications which is also cost-effective.
Mahesh Kumar, Sr. Manager – Marketing & HVAC Systems, U.P.Twiga Fiberglass Ltd