Efficient AC

There can be a shortage of electrical capacity when everyone in the world has a home conditioner. New electronics may mitigate the problem. Energy efficiency in appliances is becoming a hot topic. Several countries have now enacted legislation aimed at boosting the efficiency of products such as clothes washers, water heaters, and in particular air conditioners. Air conditioners are a special target because they are becoming more popular in Japan, Europe, and emerging countries such as China and India. In the U.S., for example, the Dept. of Energy recently issued energy-efficiency standards for numerous appliance products. Similar initiatives have been in force in Europe and Japan. In this regard, the residential air-conditioning market (about 35 million units manufactured worldwide) is by its nature a "high-impact product" for energy-efficiency programs. An air conditioner must have a SEER of at least 10 to be sold in the U.S. Higher efficiency models have a SEER of 11, 12, 13 or 14. (SEER is Seasonal Energy Efficiency Rating. It is the most commonly used measure of the efficiency of consumer central-airconditioning systems. EER, or Energy Efficiency Rating, is the most commonly used measure of efficiency for commercial air-conditioning systems.) U.S. legislation on air conditioners and heat pumps establishes more stringent minimum efficiency standards that become effective January 23, 2006. These standards are tough to hit without the use of advanced technology and are quite challenging for manufacturers. Without the use of more advanced electronic technology these standards may be potentially impractical. Such technology includes variable-speed drives powering either a standard ac induction or brushless dc compressor. Modern air conditioners incorporate power factor correction (PFC) to meet ever-more stringent efficiency standards. New circuits combine PFC with rectification to help