Table of contents:

DC network in the house reduces energy consumption
DC network in the house reduces energy consumption
Video: DC network in the house reduces energy consumption
Video: Kirchhoff's Law, Junction & Loop Rule, Ohm's Law - KCl & KVl Circuit Analysis - Physics 2023, February
Anonim

Our power grid supplies AC with a voltage of 230 volts. However, many domestic devices run internally on direct current and much lower voltages. Losses occur in this way, which is why many experts are now advocating a second power network in the house - a low-voltage DC network.

Table of contents Table of contents DC network in the house reduces energy consumption

  • What is the difference between AC and DC?
  • Advantages of a DC network in the house
  • How do you integrate a DC network?
  • For whom is a DC power source worthwhile?
  • Use of solar power without detours
  • Disadvantages of a direct current network

Table of contents Table of contents DC network in the house reduces energy consumption

  • What is the difference between AC and DC?
  • Advantages of a DC network in the house
  • How do you integrate a DC network?
  • For whom is a DC power source worthwhile?
  • Use of solar power without detours
  • Disadvantages of a direct current network

Photovoltaic systems, electric vehicles and many modern, electronic consumers such as LEDs or computers work with direct current (DC for short). The regular power grid is based on alternating current (short: AC, English: alternating current). A lot of power is lost when converting from AC to DC and vice versa. That is why it may be worthwhile for operators of PC systems in the future to think about a second, parallel network. This means that a significantly larger proportion of solar energy can be used.

What is the difference between AC and DC?

In general, electric current is the directional movement of electrical charge carriers.

Direct current

With direct current, the same amount of charge carriers only moves in one direction. This means that the direction and strength of the current are permanently the same.

Alternating current

As the name suggests here, the direction of the current changes and also the amount of the moving charge changes. However, the current takes a certain amount of time before it can run in the other direction at full power.

Advantages of a DC network in the house

Household appliances such as cell phone chargers, computers, flat screens, telephones, radios or LED lights work internally with DC voltage. With all these consumers, the alternating current from the 230 volt house network must be converted into direct current. For this you need a power supply for conversion. If you integrate a DC network in the house, you can do without these power supplies and connect the devices directly to the DC voltage. Above all, this saves costs because conversion losses are prevented.

Good to know: DC links are also increasingly used in industry. There are even pilot projects in the automotive industry to only supply entire production units with direct current.

How do you integrate a DC network?

To integrate a DC network in the house, you should simply lay a second line network parallel to the 230 V network in the building. That sounds more complex than it is: You only have to split AC and DC at one point in the house network with a voltage converter and can then route the much thinner cables through the same empty conduits and wall slots as conventional power lines - practically there are now 230 V Sockets that additionally provide USB sockets for the DC power supply. However, make sure that they do not have an integrated transformer. Or you can divide your house into several segments: those in which more alternating current is required and those in which you can do without them. This is advisable in the bedroom, for example, since AC fields have a reputation for negatively influencing sleep. If necessary, you can also install a DC network in the house together with the network cables - after all, digital devices are the most important DC consumers.

Gleichstrom-Steckdosen
Gleichstrom-Steckdosen

USB sockets on a DC network use solar power more efficiently.

Photo: Gira

For whom is a DC power source worthwhile?

A network with direct current is particularly suitable for homeowners with their own solar system, an electric vehicle or batteries as energy storage. Because these three elements all run with DC voltage. If you link consumers together through a control system, you can effectively manage consumption internally. If you want to charge your electric car, for example, the system automatically recognizes where the energy for it should come from. For example, if the sun is shining, the car is charging with energy from the solar cells. If it is not enough, the rest of the electricity is obtained from the batteries. Only when these are empty does the system tap into the public AC network. This is done without losses, even if the DC voltages are somewhat different. You also have the option of removing the conventional inverter that converts solar power into AC voltage from such a system, thereby saving further costs.

Elektroauto
Elektroauto

Electric cars can be supplied with direct current.

Photo: iStock / Sven Loeffler

Use of solar power without detours

If you have a photovoltaic panel on the roof and want to operate a computer with it, you have to consider that the direct current from the PV module must first be converted into alternating current. You lose an average of five percent. The power supplies of the computer and the monitor usually run in a partial load range with an efficiency of around 60 percent. In this case, you can only actually use between 50 and 60 percent of the electricity that you generate. If the solar power were fed directly into a DC network, the usable yield would be around 95 percent.

Disadvantages of a direct current network

  • If you want to supply different consumers with electricity using a DC network, you must note that not every device requires the same nominal voltage. For example, a laptop needs 19.5 volts, an answering machine 12 volts and a mobile phone 5 volts - this makes it difficult to find the optimal voltage and has the consequence that often only a part of the power supply units can be saved.
  • Direct current should only flow in the low-voltage range, otherwise the risk of electrical accidents is very high. Because there is no phase change, there is a risk at higher voltages that the conductor cannot be released after contact.
  • In principle, high efficiency gains are possible with a DC network for some devices, but the overall saving is usually not very high, since the largest electricity consumers such as conventional lighting (without LED), electric cooker, instantaneous water heater, refrigerator and freezer are operated with AC voltage.
  • Most devices on the market are (still) designed for alternating current and cannot be easily used in the direct current network with an integrated transformer.

Popular by topic