As the summer heats up, more residents are turning toward the sun for a cool down. By harnessing the sun’s rays, solar panels can be used to generate emission-free electricity to power central air, and solar air conditioning units are gaining popularity for homeowners who aren’t ready to invest in a full rooftop array. Solar awnings can provide shade in those sweltering afternoons, and researchers in San Diego discovered that solar panels can actually cool down the buildings they are installed on.
Air-conditioning puts a great deal of strain on the power grid during the warmer months. Transmission lines carrying power on hot summer days have limited capacity—and that capacity actually decreases when it’s hot, explains Science World Report. When voltages decline, home appliances like air conditioners start underperforming and cause additional strain on the power grid. When maximum demand is exceeded, the resulting brownouts or blackouts that occur during peak hours can leave homes without power at the hottest point of the day.
To keep cool during a blistering summer power outage, more homeowners are turning so solar air conditioning, powered by solar photovoltaics. The U.S. Department of Energy reports that American homeowners spend $11 billion to run their air conditioning each year, releasing 100 million tons of carbon dioxide into the atmosphere. The energy savings from solar air conditioning alone is enough to spark interest, not to mention the environmental benefits.
There are two main types of solar air conditioning units: hybrids and absorption chillers (swamp coolers). Hybrid air conditioning systems are more popular for residential applications and combine solar PV with direct current (DC) to switch between solar power and battery power as necessary. “Many hybrid units also feature heating capacity and include attachments for purifying water and for running additional DC appliances such as ceiling fans and lights,” reveals Fafco Solar. Solar chillers use solar energy to power a fan and motor that cools the air by blowing it over water-saturated material.
Besides saving money from producing your own clean power, solar energy can cut costs by increasing the overall energy efficiency of a house or business building. A team of researchers at the University of California – San Diego engineering school used thermal imaging to discover that roof-mounted solar panels can keep a building 5 degrees cooler during the day than a building without panels. “Talk about positive side-effects,” said engineering professor Jan Kleissl who led the study. The solar panels essentially act as roof shades, absorbing the sun’s rays and reducing the amount of head that reaches the actual rooftop by 38 percent, the study concluded. “The more efficient the panels, the bigger the cooling effect,” Kleissl said.