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Engineering

Saving Power

New alternative to save power by leaving electrical devices on standby

eduardo cesarEcoenergy’s circuit consumes little power, which helps to reduce power consumption in devices on standby modeeduardo cesar

Little dots of colored light on TVs, DVDs and other electronic devices indicate that they are on standby, ready to go into operation if one just touches the remote control. This is unquestionably convenient, but it could add 15 percent to a home power bill at the end of the month, given that Brazilians consume on average some 200 kilowatt hours (KWh). To cut this spending without having to switch devices off entirely, a group of researchers from GT Gestão e Tecnologia, a technology firm that is part of Prointec, the Municipal Advanced Incubation Program for Electronic Firms in Santa Rita do Sapucaí, state of Minas Gerais, also known as Electronics Valley, developed a device dubbed Ecoenergy that saves as much as 95% of standby consumption and reduces the bill by 15%. “A television set and a cable TV reception device on standby consume about 10 watts an hour,” says Jorge Henrique de Oliveira Sales, a researcher from IFT, the Theoretical Physics Institute of Paulista State University (Unesp) and coordinator of the project who works for GT. “When they are plugged into our Ecoenergy device, power consumption on standby drops to 0.5 watts an hour, or 95% less.”

The reduced consumption is due to the device’s circuit, developed to have extremely low power consumption but high efficiency. “We used controllers and circuits whose power consumption when they are inactive is in the order of microamperes, leaving just what is needed to operate the remote control device,” explains Sales, who is in charge of the theoretical part of the project. Two GT development engineers, Frederico Farias Ferrão and Rodrigo Gaigher, also took part in this research project, which began in January 2008. In October of last year, the project was approved in a public notice from Fapemig, the Research Aid Foundation of the State of Minas Gerais. This notice targeted the development of electronic innovation in the town of Santa Rita do Sapucaí.

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Ecoenergy was designed to be simple. The electronic device’s power cable should be plugged into Ecoenergy and then that is plugged into the socket. Ecoenergy can also have two sockets, for consumers who would like to plug in their TV set and cable TV receiver at the same time, for instance. Ecoenergy comes with a remote control, which switches all sets on and off automatically, without demanding that the user plug them in again. A timer enables one to switch off the devices at four pre-set times every 15 minutes. At the pre-set time, all the devices are switched off, whereas in standby mode they would still consume power. Ecoenergy has a red LED that only shines when the remote control or the timer are activated, which helps to maximize the power consumption reduction.

The firm, which has already submitted its patent request to INPI, the National Institute of Industrial Property, plans to start marketing the product by September of this year. “The end price hasn’t been set yet, but we figure the simplest equipment, with one socket, should be sold for some R$60.00, taxes included,” says engineer Frederico Ferrão. “The consumer will pay off the device over six months, thanks to lower power bills.” At present, the researchers are dedicated to developing a general control for electrical and electronic equipment, a project that has Fapemig support. “From a single point in the house, it will be possible to control several devices,” says Ferrão.

Cable or satellite TV converters are among the main standby power consumption villains. Research conducted last year by Idec, the Brazilian Consumer Advocacy Institute, with seven electronic products firms and four pay-TV firms, indicated consumption of 6.5 to 14 watts an hour for standby TV converters. These small boxes consume virtually the same amount of energy when they are on standby as when they are on. Their little light only goes off if they are unplugged, because they lack buttons that will switch them off entirely. On average, a pay-TV converter uses 9.2 watts on standby and 11.5 watts in operation. The institute simulated converters’ average power consumption over four hours of use. This calculation indicated that standby consumption of just one converter adds up to 6.9 KWh a month. “Such high consumption is due to the way in which the receptor’s circuitry works; even in standby mode, it remains switched on to be able to access TV programs or to get the transmission signal,” says Sales. The Idec research also showed that DVD players, for instance, consumer more energy a month on standby (0.67 KWh) than when they are used (0.51 kWh) two hours a day. As for TV sets, they consume more power when they are on than on standby. An LCD TV consumes 26.57 KWh in operation and 0.29kWh on standby, assuming it is used for four hours a day. The older TV sets with tubes, however, consume about 3 kWh a month on standby.

“The calculation indicating that equipment on standby can account for as much as 15% of one’s power bill at the end of the month is based on a two-person house, with one conventional tube TV set, a cable or parabolic antenna TV receptor, a VCR or DVD player, and one microwave oven,” says Ferrão. “The number of people is also important for the final power bill calculation, because in a home with a lot of people the standby mode consumption percentage may vary, because of the electric shower consumption. Microwave ovens on standby also account for substantial power wastage. Just to keep certain programs running, like the clock and the active touch keypad, a microwave oven has its full display circuit on; this represents, on average, consumption of 30% of all the power it uses in a month to cook or to warm up foods,” says Sales.

The project
Central device for saving power, automation and residential control; Type Aid for Innovation at Local Electrical and Electronic Production Arrangement Firms; Coordinator Jorge Henrique de Oliveira Sales – GT Gestão and Tecnologia; Investment R$ 130,610.00 (Fapemig)

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