Advantages of DC Power System for Household

ABSTRACT
There is a growing argument that using DC power systems in our homes is
far much better since its more efficient, cost less and more safe to human
beings as compared to AC power system. In this paper data is presented and
analyzed to support the argument. Information referred to is from UK
electricity service sector, and is used to compare the cost of DC power
system with that of AC power system, and a figure of much is saved per year
for using DC is indicated. This paper also focused on how solar panel is linked
to the battery, both AC-coupled and DC-coupled and advantages and
disadvantages of both systems are listed. DC and AC appliances are also
discussed in depth to give a clear picture of what is better when used in our
households. And lastly, safety concerning the use of AC or DC solar system is
highlighted, reasons to believe AC current is more dangerous compared to
DC current is explained leading to a choice to opt for DC solar power system
Discussion of the results and a conclusion of the paper marked the end of
the paper and the objectives of the paper are met and I confidently say DC
power system for household is the way to go
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CONTENTS
0.0 Abstract
.....................................................................................................................
....... ....1
1.0.0 Introduction....................................................
...................................................................3.
2.0.0 Methodology.......................................................
..............................................................3
2.1.0 Storage systems.......................................................
.........................................................3
2.2.0 DC coupled system..........................................................
.................................................3
2.2.1 Advantages of dc coupled system........................................
..........................................4
2.3.0 AC coupled
systems.................................................................................................
........4
2.3.1 Advantages of AC coupled
system.................................................................................4
2.3.2 Disadvantages of AC coupled
system..............................................................................4
2.4 AC or DC
batteries.................................................................................................
................5
2.5 Appliances
...................................................................................................................
..........5
2.5.1 Direct current appliances..................................
...............................................................5
2.5.2 Alternating current appliances..................................................
.....................................6
2.6.0
Wiring.........................................................................................................
........................6
2

2.6.1 DC or AC power
system.....................................................................................................7
2.7.0 Energy
consumption..............................................................................................
............8
2.7.1
Cost............................................................................................................
..........................9
2.8 Safety.............................................................
................................................................ ........9
4.0 Results and discussion..............................................
...........................................................10
5.0
Conclusion...................................................................................................
..........................10
1.0 INTRODUCTION
Direct current always abbreviated as DC was invented by Thomas Edison
way back in 19th century (Teggatz, Chen, Smith & Triune, 2015). DC in a circuit only
flows in one direction since polarity of voltage source is constant and the
direction of flow of the current never changes. The main source of direct
current is the batteries. Alternating current abbreviated as ac, on the other
hand was invented by Nicola Tesla. In AC polarity of the terminals
continuously change from positive to negative, the flow of current is thus
alternating and reverses direction on a certain number of times per second
(Teggatz, Chen, Smith & Triune, 2015). War of current started way back in
1880’s by the inventors Nicola Tesla and Thomas Edison. With Thomas
Edison trying to discredit Tesla’s alternating current. He goes further to
electrocute stray animals to prove ac was dangerous. Today our electricity is
predominantly alternating current but most home appliances such as
computers, LEDs, tv, woofers use direct current.
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2.0 METHODOLOGY
2.2.0 Storage systems
AC or DC coupled?
AC or DC coupling simply refer to the way solar panels are linked or coupled
to the storage system
2.2.1 DC coupled system
For decades this system has been used for off-grid solar installation and
small capacity power systems. In this system (DC coupled) charge controllers
are directly connected to the panels to charge the battery. From the battery,
battery inverters are used to convert the direct current to alternating current
for use by AC appliances in the house (Das & Agarwal, 2015). The arrangement for
this system is as illustrated in the figure below
FIG 1. DC coupled system layout
Solar controller used in our case (household) is a PWM (pulse width
modulation) type which comes with low cost
2.2.1 Advantages of DC-coupled system
 Its highly efficient
 Very low set up cost for small capacity power system
 It is highly suitable for small systems requiring one to two panels
 Its highly efficient in powering DC loads
2.3.0 AC coupled systems-this system (ac coupled) consists of solar
inverter linked to battery charger/inverter or multi-mode inverter to manage
the battery. This system is however less efficient at charging compared DC
coupled approximately 94% (Giuseppe, Laudani, & Mitcheson, 2016). The system is
illustrated by the figure below
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