Every year, Americans' heating and cooling systems produce 300 billion pounds of carbon dioxide [Source: EMagazine]. Fortunately, the European Union outlawed the refrigerants used in some old air conditioners that harm the ozone layer, and they will be illegal in the United States in 2010. But the booming economies of India and China and the accompanying rise in living conditions in those countries now means that millions of people are buying energy-draining, ozone-layer-depleting air-conditioning units. In other words, air conditioning is only making global warming worse, but what can be done to make air conditioning units more efficient? Should more environmentally friendly cooling methods replace all conventional air conditioners? We'll take a look at some options in this section.
A company called Ice Energy manufactures the Ice Bear, a unit designed to work alongside a traditional air conditioner. Like the large system used by Credit Suisse, the Ice Bear is designed to run indoors and at night, when temperatures and energy costs are lower. Ice Bear creates a block of ice at night that cools the refrigerant during the day, rather than running the refrigerant through a condenser (at peak hours) that requires a lot of energy.
Underneath the Jordan Quad Parking Lot at Stanford University, 360 miles of piping run through a four-million-gallon tank of water [Source: Stanford University]. At night, subzero ammonia -- a common refrigerant -- runs through the pipes, freezing the water into giant blocks of ice. The system, which is one of the largest of its kind in the United States, sends cold water from the melting ice throughout Stanford's campus, cooling buildings from noon to 6 p.m. When the facility was first built in the mid-1970s, it skipped the ice stage, instead directly cooling water that was piped through campus. A $22 million renovation -- completed in 1999 -- converted it to its present form, which saves the university a reported $500,000 a year on energy bills.
Evaporative coolers, also known as swamp coolers, are another popular alternative. These coolers don't use refrigerants. Instead, they use the cooling effect of water evaporation to lower air temperature. You've probably experienced the same effect after a game of basketball or a workout session. While you may initially feel hot from exertion, as sweat evaporates from your body, you'll likely start to feel chilly. Evaporative coolers utilize the same principle. They're also light on energy consumption but are often maintenance intensive and require leaving some windows open.
You may be familiar with a variety of other alternatives to traditional air conditioning systems. Opening windows to allow a draft in and using fans are both common cooling methods that aren't energy intensive. Good insulation and situating your house to take advantage of natural wind currents can lessen or eliminate the need for a cooling system, particularly if you live in a moderate climate.
If your home or office already has an air-conditioning system, there are still some things you can do. First, make sure it's a modern unit without any ozone-harming refrigerants. Close all windows when your air conditioner is running, and look into renewable power sources like roof-mounted solar panels. If you have a window-mounted air conditioner, seal the area around it and get an energy-efficient model (if you don't plan to switch to central air). Finally, make sure your home or office central-air conditioner fits the space. If yours is too big, you'll be constantly turning it on and off, wasting energy in the process.
For more information about ice-block cooling systems, making your house more energy efficient and other related topics, please check out the links on the next page.