The world runs on alternating current. Most of the things you have run on the DC. Can we speak the same language?
AC or DC? Should we switch the current?
The direct current has not disappeared. It just went underground.
In 1893, George Westinghouse won the "War of Electricity" against Thomas Edison, a decision that paved the way for electricity to conquer the world. However, it has also caused conflicts that have been growing since then.
Although alternating current is still the main standard transmission method, most power-consuming devices—cars, airplanes, light rail systems, computers, consumer electronics, and almost anything with batteries—actually run on direct current.
"The old telephone system has always worked," Brian Fortenberry, a project manager at the Electric Power Research Institute, cites another DC success story. "Reliability is excellent."
At the same time, the solar panels and fuel cells themselves generate direct current.
In order to solve the problem of mismatch, electricity usually needs to be converted from alternating current to direct current multiple times before being consumed, and vice versa. In the data center, AC power is converted to DC power through an uninterruptible power supply, which converts it back to AC power, and then sends it to the server, where the server converts it back to DC power. Every conversion will result in a loss. Multiple conversions also increase the number of times the power must be stepped from high voltage to low voltage.
In buildings, the direct current of the solar panels becomes alternating current in the inverter, and when it reaches the LED lights, it becomes direct current again. Is your laptop hot? Scrap from AC-DC conversion.
Due to advances in power electronics technology, a lot of power can be saved by suppressing these conversions. Validus DC Systems has created a system that converts AC power to DC power at the entrance of the data center, and then uses DC power throughout the building, effectively transforming the data center into a DC microgrid. General Electric, IBM, and Sun have partnered with the company.
A recent Duke University test showed that the power consumption of DC data centers has been reduced by 15%. Others believe that the potential savings are close to 30%.
According to James Coakley, CEO of Power Loft Services, as an added benefit, building the data center as a DC island reduces the number of necessary components: this improves reliability, reduces costs, and increases the number of computers that can be accommodated in a room. . Design an energy-efficient data center.
"The more devices between the power supply and the computer, the greater the chance of failure," he said.
At the same time, Nextek Power Systems, Panasonic and Sharp and other conglomerates are studying ways to introduce DC power into commercial buildings or homes so that solar panels can directly power appliances or electric vehicles. Downey Liang, director of digital applications, said that a 380-volt DC charger can charge an electric car in 10 minutes. A 220-volt AC charger requires five hours.
Even transcontinental direct current is under construction: more than 145 high-voltage direct current (HVDC) projects are underway in China, Texas and elsewhere to deliver direct current from wind farms to urban DC microgrids.
However, critics pointed out that over time, the efficiency of the power supply has continued to improve. Mixed buildings can also cause potential trouble and confusion for tenants and homeowners. AC is everywhere, which is a big advantage.
But as policy makers and corporate customers seek any possible way to reduce power consumption, going back to the past is very attractive.