Indian Institute of Technology Guwahati
Question
Asked 19th Nov, 2013
Why not to use DC power directly for home operation? What are the challenges and/or disadvantages in doing so?
With the increasing awareness of the use of renewable sources especially photovoltaic cells and availability of energy storage devices like batteries and fuel cells even in domestic level and use of electronic devices that run on DC power, I feel like for a standalone power independent house, it eliminates the need of inverter or the power supply in the distribution level itself by the distributed energy sources (DER's) can be done in DC. But there might be challenges within and disadvantages too. Let's discuss the advantages, feasibility along with the disadvantages and challenges in the deployment of such a system.
Most recent answer
Even with advancement in material science we could reach a point when we would be able to make the much smooth and superconductive brushes to reduce brush losses of the brushed DC motor. It would compete with the harmonic and other ac losses of the ac motors and replace them one by one.
Popular answers (1)
Kyoto University
There is no apparatus which need ac anymore in home. Almost all electric apparatus in home are connected to ac power. However, ac power is converting dc in them at their operation. Recent PM motors cannot also be driven directly by ac without converters. It implies dc is enough for these applications. All reason of applying ac are to keep the conventional apparatus in electric power network, and to feed power companies. Multiple conversion will waist energies in the steps. Therefore, in the local area, we had better select dc. The problems remains in isolations and network safety. These will be solved soon. IEEE now starts to write standard for home dc use.
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All Answers (17)
Argonne National Laboratory
The few advantages of using DC power in distribution level for me includes:
Harmonic elimination, no concern regarding power factor correction, relatively simple grounding and lower maintenance cost and increased reliability interms of the elimination of DC-AC converters.
1 Recommendation
Indian Institute of Technology Roorkee
In AC distribution network, using transformer required voltage can be obtained easily. Considerable power loss saving and hence efficiency of distribution could be increased. Most of the home appliance work on AC. Harmonics can be removed by providing simple filters.
DC can use for transmission (long distance )
we cant use in home appliances , we cant design each equipment to work on dc
and it quite to danger than AC .
National Institute of Technology, Durgapur
One of the disadvantage of DC transmission is designing the Protection Switchgear. DC current generally will not have natural zero crossing and because of this forced zero is obtained by using the combination of L-C & R. Though it is not impossible but the circuitry is typical and the same has to be manufactured at voltage levels and implemented. Further, shock hazards are too dangerous in DC.
Indian Institute of Technology Roorkee
Due to higher starting torque of DC series motor, we use DC in traction. As power factor is unity, considerably high power can be transmitted with less power loss so H.V DC is used for long lines. Leakage current due to long line capacitance is eliminated and transmitting efficiency is improved compare to H.V AC.
With solar power generation with storage battery used, low voltage D.C utilization would be more convenient to use efficiently for individual houses in remote.
Indian Institute of Technology (Banaras Hindu University) Varanasi
Due to development of BLDC motors, it is feasible to use low voltage DC power for domestic applications like fans, mixer grinders, washing machines etc. For lighting LED is also affordable. Certain research groups in IIIT Hyderabad seems to be working on this aspect to provide low voltage 70V DC for domestic appliances.
With DC you cannot use transmission of power, because of ohmic loss when it is done at low voltage.
Rajeev Gandhi Memorial College of Engineering and Technology
Due to well existence of AC load home applications such as washing machines, freezers etc, for which DC power can not be adopted....You mean power from renewable energy sources like PV cells or fuel cells need additional equipments such as inverters to feed AC loads..in addition with battery banks.....maintenance of battery banks and elimination of harmonic effect is cumbersome and costly...
Kyoto University
There is no apparatus which need ac anymore in home. Almost all electric apparatus in home are connected to ac power. However, ac power is converting dc in them at their operation. Recent PM motors cannot also be driven directly by ac without converters. It implies dc is enough for these applications. All reason of applying ac are to keep the conventional apparatus in electric power network, and to feed power companies. Multiple conversion will waist energies in the steps. Therefore, in the local area, we had better select dc. The problems remains in isolations and network safety. These will be solved soon. IEEE now starts to write standard for home dc use.
4 Recommendations
École de Technologie Supérieure
Besides an incredible amount of capital already invested in AC-powered devices, from a theoretical standpoint, I suppose that since DC cannot be stepped up or down with the help of transformers, loads would have to work on the voltage that is being supplied and that any residual tension would have to be distributed among resistors and dissipated as heat. Powering high-voltage devices would be impractical.
Indian Institute of Technology (Banaras Hindu University) Varanasi
Current day technology boost-buck converter enables us for minor adjustment of DC voltage for any domestic appliances. Way back in 1889, when Induction motors were invented, before that it was all a DC. Though people were knowing the generation of AC and step up and down of ac voltage through transformer. After 1890, a lot of debate was there in UK (as reported by Prof E R Laithewaite in one of his book), whether to go for AC or DC.
People of that era had chosen the AC because it could be easily stepped up & down and transmitted at higher voltage. Three phase AC were chosen so that mankind could make use of the marvellous invention of three phase induction motor.
Current day technology of PMBL motor is proving an edge over induction motor technology, in terms of size and energy saving. I hope that in coming years many domestic and industrial appliances will have PMBL motors as a main drive component.
2 Recommendations
Dayalbagh Educational Institute Agra
Now a days the utilization of the DC supply in the building home/ industrial is increases day bay day.
2 Recommendations
Dayalbagh Educational Institute Agra
most off the appliances in the homes like computer, TV, CFL, etc are only DC compatible.
1 Recommendation
Dayalbagh Educational Institute Agra
As most of the governments are promoting the renewable energy sources and most of the renewable sources like solar photovoltaic and storage battery bank are DC source. so we can use electricity directly in DC form.
1 Recommendation
Dayalbagh Educational Institute Agra
for more details and advantage of DC system you may follow
Conference Paper DC Power Distribution System for Rural Applications
2 Recommendations
University of Technology Yatanarpon Cyber City
Most of the electrical products for the domestic use are AC.
Aalborg University
The challenge is commercial home appliances. Theoretically it is absolutely possible.
Indian Institute of Technology Guwahati
Even with advancement in material science we could reach a point when we would be able to make the much smooth and superconductive brushes to reduce brush losses of the brushed DC motor. It would compete with the harmonic and other ac losses of the ac motors and replace them one by one.
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