Friday, June 14, 2013

Air-Conditioning Options

Air-Conditioning Options

Which is more energy-efficient--central air or window units?

Dear EarthTalk: Now that hot weather is coming, I want to upgrade my home’s A-C. Which are the most energy-saving models and should I go central air or window units?—Jackie Smith, Cary, N.C.

According to the American Council for an Energy Efficient Economy (ACEEE), energy consumption for home air conditioning units accounts for more than eight percent of all the electricity produced in the U.S., at a cost to homeowners of $15 billion annually. Besides the cost, all this cooling leads to annual emissions of about 195 million tons of CO2—or two tons per year for each American home with A/C.

Of course, foregoing A/C entirely is the most energy- and cost-efficient way to go, but some of us need a little cooling for comfort, especially in warmer climates. If A/C is a must, buying the most efficient model is the way to save money and pollute less. Fortunately, a new generation of much more efficient room and central A/C units means that upgrading will likely pay for itself in energy savings within just a few years.

The main factors to consider in choosing a new model are cooling capacity (measured in British Thermal Units, or BTUs) and Energy-Efficiency Ratio, or EER. To determine the correct BTU rating for a given space, multiply the square footage by 10 and then add 4,000. Meanwhile, a given unit’s EER is the ratio of cooling output divided by power consumption—the higher the EER, the more efficient the air conditioner.

According to the U.S. Department of Energy, national appliance standards require room air conditioners to have an EER of 8.0 to 9.8 or more, depending on type and capacity. Units with an EER rating of 10 or above typically qualify for the federal government’s ENERGY STAR label, which appears on especially energy-efficient appliances. Check out the ENERGY STAR website for lists of qualifying A/C models.
The Association of Home Appliance Manufacturers (AHAM) says that the average EER of room A/C units rose 47 percent from 1972 to 1991. To wit, replacing an older room unit with an EER of five with a new model with an EER of 10) would result in a 50 percent energy cost savings associated with A/C.
For More:

Comment by Anumakonda Jagadeesh

Excellent Post.

Mumbai city's recent power load flow pattern, which gives an indication of which gadgets consume more power, indicates that air-conditioners alone guzzle nearly 1,000 MW of the 2,700 MW of power that the city consumes every day.

More than 6 lakh out of Mumbai's 37 lakh residential and commercial consumers have air-conditioners at home; over 1,200 larger establishments use centralised air-conditioners. The first sub-group consumes around 400 MW of power daily and the larger commercial establishments account for 600 MW of power. The city has to buy 400 to 500 MW of power from outside during the day at an average cost of Rs 12 per unit.

There is another problem with Air conditioners both at home and offices: During frequent power cuts(which we had this year) the battery back up is not sufficient to run ACs. So one possible solution for the future is to construct houses and offices with crss ventilation so that roof top heating is reduced. Traditional mud houses in Rajasthan were cooler in summer and warmer in winter.

The Eastgate Centre is a shopping centre and office block in central Harare,Zimbabwe whose architect is Mick Pearce. Designed to be ventilated and cooled by entirely natural means, it was probably the first building in the world to use natural cooling to this level of sophistication. It opened in 1996 on Robert Mugabe Avenue and Second Street, and provides 5,600 m² of retail space, 26,000 m² of office space and parking for 450 cars.

Modernise the traditional – Traditionalise the modern

No comments:

Post a Comment