AC firms take the sweat out of temp control

Many AC brands are prepared for the future with default temperature that is higher than what the govt has prescribed

On Tuesday, when Delhi was reeling under the usual monsoon humidity, the city’s power consumption reached a new peak of 7016 MW. There weren’t any major power breakdowns but the demand soared as air conditioners were switched on to arctic temperatures.

A fortnight ago, on June 25, the Bureau of Energy Efficiency (BEE) had issued an advisory asking people to keep the air-conditioning temperature at 24-25 degrees Celsius. “Typically, room temperature is set between 20 and 21 degree Celsius, whereas, as per the comfort chart, it is suggested that the ideal temperature could be maintained at 24-25 degrees,” say the guidelines.

This comfort zone is based on standards worked out by the American Society of Heating, Refrigerating and

Air- Conditioning Engineers, says Abhay Bakre, director general, BEE. “Lower the inside temperature, more is the energy loss since premises in

India have gaps that allow cool air to escape. For instance, if the temperature is set at 21 degrees and outside it is 35-38 degrees, then the cooling loss is more than it is if the temperature is set at 24 degrees.” This explains why in an airplane, which is airtight, even 22 degrees feels overwhelmingly cold.

The bureau estimates that by increasing the room temperature by 1 degree, electricity consumption can be reduced by about 6 per cent. Cranking it up from 20 to 24 degrees implies the potential to cut electricity consumption by about 24 per cent. At an aggregate level, it could lead to potential saving of about 20 billion units (kilowatt per hour) of electricity.

Shashi Aurora, chief executive officer for the Lloyd division of Havells, one of the largest electric appliances company in the country, cites the example of Japan where the government promotes energy conservation by asking all offices to run ACs at 27-28 degrees.

To start with, BEE has put the onus of maintaining 24-25 degree temperature on commercial users themselves. So, people operating cooling systems at commercial buildings, airports, hotels, shopping malls, and offices are required to be suitably trained to maintain the prescribed temperature without adversely affecting the comfort conditions. Simultaneously, managers of commercial buildings have been asked to maintain appropriate humidity and airflow to conserve energy and ensure good health of occupants.

“Any deviation from the guidelines should be considered with the approval of the head of the organisation,” say the guidelines. Currently, the instructions are not mandatory, but the Union power minister RK Singh has indicated that they could be made compulsory in the future.

The government move is part of an ongoing exercise to save electricity. It started with star labelling for electric appliances that was introduced along with Energy Conservation Building Code to reduce demand for space cooling. These were initially advisory but later became mandatory for new products and buildings.

Insulating buildings is one way of keeping energy consumption low for both cooling and heating purposes. Norwegian buildings, for instance, had to follow regulations on thermal insulation since 1949. The Norwegian regulations set limits on net energy demand based on some fixed input parameters, including internal heat gains by equipment and people, hot water use, operating hours, set-point temperatures for heating and cooling, minimum ventilation rates, and default lighting energy. The European Union's main laws for promoting energy conservation are the 2010 Energy Performance of Buildings Directive and the 2012 Energy Efficiency Directive.

The new BEE guidelines for air-conditioners exempt premises where specific ambient conditions are required like food processing units and operation theatres. They are not applicable for winter climatic conditions as well.

Some AC companies already follow a higher default temperature than what is being prescribed. For instance, all Panasonic air-conditioners set 25 degrees as default temperature, which the users can change according to their requirements. “Our current default AC setting supersedes the government’s 24-degree temperature proposal. Over and above this, we have further equipped our new line of Aero Series ACs with iAuto X feature and Econavi Sensors, which reduce energy wastage by up to 65 per cent,” says Gaurav Sah, business head, air conditioner group, Panasonic India.

AUTO-X sensors provide powerful instant cooling through high-powered inverter control using the company’s thermal enhancement technology. Twin flaps in the air-conditioner direct the airflow for fast cooling. The company claims delivering the powerful cooling airflow helps in 35 per cent reduction in the time required to reach the set temperature. ECONAVI Intelligent Sensors, on the other hand, detect “unconscious waste of energy using the human activity sensor and sunlight sensor”. It is able to monitor human location, movements and sunlight intensity. It then automatically adjusts cooling power to save energy.

There is no default temperature, however, for Lloyd’s room ACs . “The consumer chooses the temperature to their liking based on the ambient conditions in the city,” says Aurora. Customers in Delhi may choose to keep it at 22 degrees whereas in Mumbai people may prefer to keep it at 24 degrees. “Even if at the default temperature, the customer would need to have the flexibility of changing it. Hence, it may not be feasible for the government to recommend a default temperature for residential ACs. It can, however, specify a minimum temperature, say at 21-22 degrees,” he adds.

By and large, manufacturers are welcoming of the proposal. Sah says, “(The move) can seemingly help the nation follow on to its robust sustainability goals.” These guidelines, though difficult to implement, could bring in more sobriety to demand in India, where often a sudden change in weather can lead to fluctuations in power consumption. Though India has a subdued growth in power demand of 4-5 per cent on an annual basis and high power demand is in the interest of producers, they are united at least on one mission: that is, to conserve electricity.