Stand by
José Pomílio informs what standby mode can represent
up to 15% of energy consumption in a home

CARLOS TIDEI

Attempts to reduce energy consumption proliferate as discussions about generation alternatives occur. If, on the one hand, it is necessary to define other sources to meet the growing demand, on the other hand, the rational use of energy must be promoted, reducing consumption efficiently, without affecting the quality of services provided by electricity. Replacing incandescent lamps with tubular fluorescent lamps in homes and offices, or mercury lamps with sodium vapor in public lighting, are examples of conservation. The use of compact fluorescent lamps, although they represent a reduction in consumption, present other problems associated with what is called “Electrical Energy Quality”. According to José Antenor Pomílio, professor at the Faculty of Electrical and Computer Engineering (FEEC) at Unicamp and president of the Brazilian Society of Power Electronics (Sobraep), within the context of better use of energy, minimizing stand consumption should be considered. by. When electronic equipment is left on standby, without operating, consumption is very high. Measurements reveal that it corresponds to 10% to 15% of the electricity used in a middle-class home, where there is a clock radio, cordless telephone, microwave oven, stereo, television, computer, VCR, etc.

“To do nothing. The only benefit is the comfort of pressing a remote control. People must realize that this expense represents half of the cut target imposed by the government”, warns the professor. In Japan, where domestic consumption accounts for 50% of the energy generated, 13% of which is standby, legislation was implemented imposing a drastic reduction. The Japanese have many automatic electronic devices and are unlikely to change their habits. The equipment is permanently connected to the network, through the concept of “smart home and building”. Then, the law began to require that devices, after a first stage of stand by, drop to a minimum consumption level, from which they will only react when the remote control is activated. This requires the installation of a circuit the size of a coin in the electronics, with which each of them starts to consume a maximum of 1 watt, compared to 10 to 15 watts spent without this modification. In other words, a drop from 13% to 1%. The technology exists and has already been incorporated into the equipment. “This reveals that there is a global discussion around this issue”, highlights Pomílio.

Tensão - Another controversial measure is the 5% reduction in tension announced by the government. There is no certainty about the reduction in consumption, estimated at 2% by government technicians, based on a model of electrical loads. “How much savings it will actually represent depends on the type of loads fed”, explains the Unicamp specialist. He explains that there are three types of loads: “constant impedance”, such as lamps and showers, for which you should really expect a reduction, as each lamp will be weaker and the shower will heat up less; “constant current”, where the drop will not be so significant; and “constant power” ones, typically household electronic devices and industrial, where, in addition to no savings in consumption, there will be greater loss of energy transmission.

“Electronic equipment works normally when reducing the voltage in the specified range, but the current increases. The increase in current passing through the wiring increases losses. It is a process that goes against the expected result. This increase in consumption is marginal, very small, around 0,1%” says the professor. “Constant impedance” type devices, but with temperature control, such as electric irons, are also unlikely to produce savings with lower voltage. This is because the user will readjust the device to obtain the desired temperature. Savings are obtained on equipment that does not have this control, such as lamps and showers. In the case of showers, people tend to raise the temperature. If it is already hot and there is nothing more to increase, it results in savings.

In the case of refrigerators, which have an automatic restart system when the interior temperature rises, it will have to run longer to carry out the cooling process and possibly increase consumption. The alternative of reducing voltage is used in some regions of the United States during peak hours. At this time, a large part of the load is of the “constant impedance” type (showers and lamps), which leads to savings.