Date:21/10/2005 URL: http://www.thehindubusinessline.com/2005/10/21/stories/2005102101211900.htm

Back How to use ACs with energy-efficiency

Our Bureau

Thiruvananthapuram , Oct. 20

ENERGY consumption by air conditioners can be reduced by 30-50 per cent by proper selection, operation and retrofit practices.

Proper sizing, selection, installation, maintenance, and correct use are keys to lowering power costs entailed by an AC, says Mr R. Harikumar, Secretary, Society of Energy Engineers and Managers (SEEM).

SEEM discussed the issue at a two-day residential national workshop on `Energy efficiency in Refrigeration and Air-conditioning' held last week in Munnar. More than 50 senior and middle-level managers from a cross-section of industries and establishments were in attendance. The Indian Renewable Energy Development Agency (IREDA) was a co-sponsor.

It is generally accepted that "the right way" to specify an air conditioner is to calculate the loads and select a piece of equipment that will provide comfort to the customer in a wide variety of conditions. Unfortunately this is rarely practised.

Many a time have ACs been found buzzing away to `cool down' the impact of heavy heat inflow from ceilings, glass facades, room openings and avoidable parasitic loads, but not to the comfort level required by humans and sensitive equipment. On a sunny noon, the temperature under the roof of the top floor could be nearly 48°C. The resultant heat flow into this AC room is significant owing to the large temperature gradient between the AC grill and the roof.

Simple solutions like coating the rooftop with white paint could reduce the heat ingress and thereby power consumption considerably. This can be applied even in the case of non-AC rooms for better living condition.

Computerised system that uses software and sensors are available for automatically detecting and diagnosing problems in commercial air conditioning units and for recommending specific repairs. Absorption-based air conditioning, in the form of large absorption chillers for major commercial-building or industrial applications, is the most cost-effective way of air conditioning when waste heat is available in the facility.

Solar refrigeration is another technology that should be thought of when choosing sustainable development options in developing countries. Establishment of infrastructure required for the production of solar refrigeration units and the setting up of educational programmes and training in the operation and maintenance of solar plants as well as in the design and instrumentation aspects are now identified as priority actions.