ACs heating up your electricity bill? Here’s how that could change

The super-efficient split AC prototypes were among the winners of the Global Cooling Prize—a $3 million challenge announced in 2018 to develop and demonstrate transformative cooling solutions. The prototypes are made using components similar to those in use today. But what sets them apart is how they sense and adjust to real world conditions, said Ankit Kalanki, principal at RMI. They run on more efficient compressors, improved coil design and advanced sensors to achieve target indoor conditions. The units won’t come cheap, but the payback period is estimated to be under four years.

An AC that cuts energy consumption by 60% will be a gamechanger for India. The country is already the world’s fastest-growing AC market and projected to have over 1 billion room units by 2050. That will propel electricity demand for cooling nine-fold compared to 2022, as per the report released last month by RMI, which cautioned that widespread adoption of current AC technology may jeopardize both the electricity grid and national climate goals.

This, in no small way, is because the backbone of cooling technology has not seen a radical reset in more than a century. A few startups, in India and globally, are now working on a mix of technologies to change that. They are trying to marry age-old methods such as evaporative cooling with the latest compressor technology to reduce energy use.

Last year, for instance, Ambiator, a Hyderabad-based startup, started selling a machine it claims “cools like an AC, but costs like a cooler”. The technology takes a leaf from traditional desert coolers, which use evaporative cooling technology. In this rather ancient method, hot air drawn in by a powerful fan passes through a wet cooling pad, supplying fresh and cool air indoors.

Some, such as the Florida-based Blue Frontier, are using desiccants to soak up excess humidity instead of using energy-intensive compressors (studies show that ACs use up to 25% more energy just to manage humidity).

Others, such as the UK-based Barocal, are exploring a brave new world of solid-state cooling, using low-cost organic crystals instead of polluting refrigerant gases.

A business on steroids

A factory floor can be meditative. At a manufacturing unit run by Haier Appliances in Uttar Pradesh’s Greater Noida, hundreds of hands work in silence. Multiple parts of a machine flow in a stream, like fragments of an idea. Copper coils, compressors and blowers pass by on conveyor belts, moulded by human touch. At the end of the assembly line, every two minutes or so, a completed outdoor air conditioning unit pops out, as if by magic.

In one corner of the Haier factory floor, heavy-duty units are tested in a lab, which simulates extreme weather conditions, to ensure that air conditioners (ACs) can still cool a space when outside temperatures touch an unthinkable, skin-scorching 60°C. And that they are able to deliver crisp breeze when the air outside is soaked with moisture.

For manufacturers, the climate crisis is as much a test as it is an opportunity. They have to deliver machines that can function in extreme conditions, at an affordable price point. Last year, when the summer was the warmest on record, residential AC sales surged nearly 30% on-year to touch a record 14 million units. Room AC makers clocked a revenue of around ₹45,000 crore, the highest ever. Sales are estimated to double in four to five years, as the segment is growing by more than 15% annually, top industry executives told Mint. It’s a business on steroids.

In the consumer durables business, ACs are the engine that will drive both volumes and value in future, said N.S. Satish, president of Haier Appliances India. Household AC penetration in India is at sub-10%, compared to nearly 40% for refrigerators. So, there is enormous headroom to grow, assuming every family that owns a refrigerator today will eventually own an AC.

India’s room AC production capacity is estimated to grow by 40% in the next three years, ratings agency Icra said in a report last October. On its part, Haier Appliances, whose parent company is headquartered in Qingdao, China, is expanding its annual production capacity in the country from 1.5 million units currently to 4 million units.

The growing demand for cooling solutions and other consumer durables presents a lucrative opportunity, and large corporations that are not already in the business are looking to get in on the action. Late last week, Bloomberg reported that Bharti Airtel founder Sunil Mittal is in advanced talks to acquire a 49% stake in the Indian unit of Haier, citing people familiar with the matter.

On the flipside, more ACs will strain electricity grids, and increase both energy consumption and greenhouse gas emissions manifold. Also, an ever-increasing number of ACs running for longer hours will worsen the heat island effect in cities—ACs spew out hot air, often 5-10 degrees warmer than the ambient air temperature. When heat trapped by the dense concrete of cities during daytime is released at night, hot air from ACs is an added load, turning them into pockets of heat, relative to the cooler areas around them. Nights will turn uncomfortably warm.

An ever-increasing number of ACs running for longer hours will worsen the heat island effect in cities.

Besides, ACs use chemical refrigerants that are potent greenhouse gases, trapping more heat in the atmosphere than even carbon dioxide. For instance, R-32, a commonly used hydrofluorocarbon refrigerant gas, comes with a global warming potential (GWP) of 675. This means R32 traps 675 times more heat than the same amount of CO2, over a 100-year period. So, even minor gas leaks from ACs have a significant impact.

Driven by discomfort

The business of cooling is driven by discomfort, joked one senior industry executive. Although it was made in jest, the remark is spot on. Last summer, when temperatures breached 50 degrees celsius in many Indian cities, consumers made a beeline to purchase ACs. The pain was so acute that families that did not own a refrigerator or a washing machine queued up for ACs, upending the standard hierarchy of purchase. Despite an early onset in April, the summer has been more bearable this year, though the Met Office has forecast a higher-than-normal number of heatwave days.

“The cooling challenge will intensify as India gets to 30 million ACs by 2030. Technology gains have been incremental so far…what we need is a breakthrough,” said B. Thiagarajan, managing director of Blue Star, a leading brand. While televisions went from being bulky boxes using power-hungry cathode ray tubes to slim LED-variants, air conditioners remain just as bulky as they were decades ago. And the technology driving them hasn’t evolved much.

The cooling challenge will intensify as India gets to 30 million ACs by 2030. Tech gains have been incremental so far…what we need is a breakthrough.
—B. Thiagarajan

The first modern air conditioner was developed in 1902 by Willis Carrier, an engineer, while trying to solve a specific problem: excess humidity damaging magazine pages at a publishing house in Brooklyn, New York. Carrier developed a system that blew air over coils filled with cold water. While excess humidity condensed on the coils, the system also produced cooled air. Within two decades Carrier developed a finer version, a centrifugal compressor, which was widely used to cool air inside movie theatres.

Present-day ACs follow the same scientific principle first used a century ago: using a compressor to repeatedly alter the state of a refrigerant gas. The process follows from a law of thermodynamics: when a liquid converts into a gas, it absorbs heat. Inside ACs, chemical refrigerants evaporate and condense in repeated cycles within a closed system of coils, allowing heat to be transferred and ejected outside, while cooling the air within a room. This is vapour compression technology, and it continues to be the backbone of room AC technology more than a century on.

The process is energy intensive. Despite improvements driven by energy efficiency standards, both globally and in India, a typical split AC still consumes 15-20 times more electricity than a fan.

In short, there is a heavy price to pay for human comfort.

District cooling solutions

Vapour compression technology has reached the theoretical limits of efficiency, argues Chandra Bhushan, chief executive of the Delhi NCR-based climate think tank iFOREST.

“It’s time to switch to hybrid technologies and use green refrigerants with a low global warming potential. We must think beyond individual ownership of ACs and look at centralized solutions like district cooling, which is more energy efficient. But manufacturers will want none of it…that’s the politics of cooling,” adds Bhushan, who is also a member of the refrigeration and air conditioning sectional committee of the Bureau of Indian Standards.

District cooling is a solution where multiple buildings in an area are connected to a centralized system. In this model, large centrifugal chillers produce chilled water, which is piped to buildings for cooling. The process uses water instead of refrigerant gases and can reduce energy use by at least a third.

“Think of it as cooling-as-a-service, like piped gas or electricity supplied to homes. In India, the only notable project is the GIFT city in Gujarat. A regulatory push can hasten adoption in upcoming residential and commercial projects,” said Anju Mary K., head of sustainability at Danfoss India, which offers industry-scale energy solutions.

Globally, district cooling is gaining in popularity, powering iconic buildings such as the Burj Khalifa in Dubai, schools and hotels in Hong Kong, and the Louvre museum in Paris.

Happening now

Is it possible to reduce the energy required for cooling by making devices more efficient? Can a radical shift in the way ACs are built slash energy consumption? Also, is it possible to move to a benign refrigerant, one that is more planet-friendly? These are the questions driving the push to find more energy-efficient solutions.

Since the advent of modern ACs a century ago, compressor technology has undergone some changes. A notable one was moving from fixed-speed to variable-speed compressors (inverter technology) in the early to mid-2000s. Inverter ACs are more energy efficient, by at least 30% or more, compared to those using older generation compressors. However, as the RMI assessment shows, this is not enough.

The good news is that companies around the world are working on alternatives. For instance, Ambiator, the Hyderabad-based company cited earlier, upgraded conventional air cooler technology by adding sensors to regulate water flow and alternate between dry and wet cooling to achieve thermal comfort. Unlike traditional coolers, the Ambiator model exhausts air outdoors. The air circulation prevents the mugginess associated with coolers. And unlike ACs that recirculate air within a space, pushing CO2 levels higher, Ambiator promises a more lung-friendly alternative.

The pitfall is that the machine is a bulky five-tonne capacity unit more suited for commercial spaces. Also, it won’t work within 100 km of India’s coastline, where humidity levels are high. “It still solves for 70% of India, which faces dry-heat conditions. We are now working on a compact residential system combining evaporative cooling with a compressor. The latter will kick in to manage excess humidity while low-energy evaporative cooling will take care of dry heat,” said Jeeten Desai, Ambiator’s founder.

Godrej Appliances showcased a similar technology at the Global Cooling Prize. The Godrej prototype, which was among eight short-listed finalists announced in 2019, uses a hybrid technology integrating vapour compression with advanced evaporative cooling. The prototype used a green, propane-based refrigerant (R290) with negligible global warming potential (224 times lower than R32, to be precise). Godrej is now working towards a commercial launch of this model in the next 2-3 years.

In fact, way back in 2012, Godrej began selling an energy-efficient model with the R290 refrigerant. It sold some 500,000 units before withdrawing it from the market after a few years. Why? “Back then, it was the most energy-efficient model. The market perception was that R290 is highly flammable (it still is). But so are domestic LPG cylinders, which hold 14 kg of inflammable gas—a much higher quantity compared to the refrigerant used in an AC (less than a kg for a 1.5-tonne unit),” said Kamal Nandi, business head and executive vice president at Godrej.

In the near future, when regulations mandate use of green refrigerants, R290 will be the fallback option, Nandi said. Being a signatory to the Kigali amendment to the Montreal Protocol, India will have to phase down polluting HFCs beginning 2032.

Meanwhile, unmindful of the rather technical debate around refrigerants and compressors, a quiet change is underway in India’s hinterland. Annual air-cooler sales are now estimated to be at 18 million units, with branded ones accounting for a third of the market, said Deba Ghoshal, former vice president at Voltas Ltd. Air coolers use a tenth of the energy consumed by ACs and can comfortably cool in dry-heat, low-humidity regions.

“With new cooling-pad technology like honeycomb pads, humidity control sensors, powerful air throw and energy-efficient motors, air coolers are turning out to be a promising and sustainable solution. Families are no longer embarrassed to own one,” said Ghoshal.

To some, air coolers may seem like going back in time. But it’s a sensible choice, being both pocket and planet friendly.