Comparative Analysis of AC and DC Electrical Energy Systems

This report provides a comprehensive comparison between Alternating Current (AC) and Direct Current (DC) electrical energy systems, analyzing their key differences in terms of cost, safety, and energy consumption. The introduction highlights the historical context of AC and DC, mentioning the contributions of Edison and Tesla and the ensuing "war of currents." The literature review explores the advantages and disadvantages of each system. The report then delves into the working principles of AC and DC, including their generation and flow characteristics. The core of the report focuses on a comparative study based on relevant criteria such as cost (including copper wire, converters, and energy costs), safety (highlighting the dangers associated with each form), energy usage, and energy storage. The analysis includes tables to illustrate cost comparisons and energy consumption percentages in a hybrid house setting. The conclusion summarizes the findings and provides insights into the suitability of each system for different applications, particularly in the context of hybrid renewable energy systems. The report emphasizes that DC is cheaper and more energy-efficient than AC.

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Abstract
Electrical energy is in two major form since its invention, these two forms were basically
invented by different individuals. These includes the Direct current form which was invented by
Daniel Edison and the Alternating Current which was invented by Nikole Tesla. Over many
years since there invention there have been deep discussion which form is better than the other
and should be used extensively. This paper hence will analyzed the key difference of these form
of renewable electrical energy which is produced from several generation planet (hybrid). The
comparison will be on cost (which one is cheaper than the other, safe, i.e which one is more
dangerous than the other, and the energy consumption, i.e in which form is more energy
consumed.

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Table of content
Contents
Abstract............................................................................................................................................2
Table of content...............................................................................................................................3
List of table......................................................................................................................................3
Introduction......................................................................................................................................4
Literature review..............................................................................................................................4
Working and Difference between AC and DC............................................................................6
Alternating Current (AC).........................................................................................................6

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Direct current (DC)..................................................................................................................8
Research questions.........................................................................................................................10
A comparative study based on the relevant criteria...................................................................10
Cost.........................................................................................................................................10
Safety......................................................................................................................................13
Energy usage..........................................................................................................................14
Energy storage........................................................................................................................14
Conclusion.....................................................................................................................................15
List of table
Table 2: Showing Cost of electrical energy and electronic power converters................................9
Table 3: Showing the consumption in a typical hybrid house in percentage................................10
Table 4: Showing the cost comparison between AC and DC in hybrid house..............................11

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Introduction
When the invention of electricity took place up to now there has been several changes
and some of these key changes in the form in which electricity can be for renewable energy.
Today the main and the only ways in which electricity can be are the direct current (DC) and the
alternating current (AC). Current or electricity is the movement of the electrons in a conductor
(always referred to as wires). The key difference between the two is the direction of flow of
electrons. Just from their names in direct current, the electrons will flow in just one direction
while in alternating current the electrons will flow as it keeps on switching directions i.e
sometimes going” backwards” and sometimes going “forward. ”
Literature review
The comparison between which form of electrical power is better and should be adopted
led to cold war between the Direct current guy known as Thomas Edison and the man who
invented AC electricity by the name Nikole Tesla. Everyone has the key advantage of his
invention and the limitation of the other person´s invention (Arrillaga, 2010). For example,
Nikole Tesla claimed that in the transportation of DC power there is a lot of power loss since this
form cannot be transformed ( stepped up or down) while Daniel Edison claimed that AC power
is very dangerous and can cause the death of an individual when in operation due to its operating
frequency.
Edison explained this using a dog which was electrocuted and he liked this to danger this
form may cause to a human being if it is fully adopted. The two were both rights in their context

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and for this, it is better to fully analyse the difference between the two and this will help us to see
which form should be adopted where and why and this may also depend on an individual´s
preference (Bostick, 2013). The two forms of electrical energy are generated from several
renewable energy and transported to hybrid houses. The flow of DC current can be illustrated
using the following diagram;
Figure 1: Showing the current flow in a DC (McNichol, 2011).
And in AC the flow of current can be illustrated using figure 2 below;

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Figure 2: Showing the current flow in AC form (McNichol, 2011).
This paper will for sure help us to analyze if it is true that the usage of DC energy in a household
(with Dc appliances) is far more efficient and economical and safer than using Ac power.
Working and Difference between AC and DC
These two forms of electricity operate in slightly different in terms of the flow of electric current
just as briefed in the introduction.
Alternating Current (AC)
AC is generated by utilizing an alternator. It is made to generate AC inside a field of
magnet, a loop of conductor is rolled, from which actuated current will move in the wire. This is
so due to the wire turns and enters into diverse magnetic polarity periodically, the current and
voltage substitutes within the wire (Arrillaga, 2010). The symbol for the AC source is given in
the figure below;
Figure 3: Sowing AC source (McNichol, 2011).
And the process of generation of the AC power can be summarized using the following diagram;

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Figure 4: Showing waveform during the generation of AC power (McNichol, 2011).
The generated current in most cases is a sine wave but it can be triangular and square
waveforms. The sine wave is in most cases preferred due to its simple calculations and ease in a
generation. These AC waveforms can be easily understood through the use of mathematical
terms.
V(t) = VP Sin (2πft + Ø) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Where V (t) is the function time of voltage, it implies that our voltage will change with
the change in time. VP is the amplitude of the sine wave as illustrated in figure 4 above. It
shows the maximum voltage the sine is able to reach in both directions (positive and negative).
The sin function explains that the voltage is in form of the periodic sine wave and will operate as
a smooth oscillator at 0V. φ shows the phase of the sine wave during the generation (Goodstal,

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2013). The periodic nature of the sine wave always shifts by 360°. When the US is taken as our
reference then the above equation can be rewritten as below for the Root Mean Square value.
V(t) = 170 Sin ( 2π60t ) . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
And the RMS sine wave which is fully labeled is illustrated in the figure below;
Figure 5: Showing RMS sine waveform (McNichol, 2011).
Direct current (DC)
Basically, the main source of Dc is through the batteries, photovoltaic cells, electrochemical.
And the symbol for the DC source is illustrated in the following diagram;

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Figure 6: Showing the DC source (McNichol, 2011).
But of late the use of AC is the most preferred way of generating DC and it is simply
done by the use of diodes in a bridge (bridge rectifier) to change AC form to DC form what in
most cases is known as DC rectification (Weiss, 2010). This process of conversion passes
through several processes like the AC power supply is stepped down to the required voltage and
current. Then the stepped down voltage is passed to a full wave bridge rectifier which consists of
4 diodes (Hemami, 2017). The output of this voltage will have some ripples due to the diodes
employed here hence a filter is employed to help filter out the ripple voltages. The filter consists
of capacitors and inductors. The capacitor is connected in parallel while the inductor is
connected in series to the full wave bridge rectifier. The DC output will hence be a very smooth
voltage which can be used in electronic devices without any problem. The RMS value equation
for the conversion of AC to DC is given below;
RMS= Vp
√ 2 . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Where Vp is the peak voltage.
In hybrid solar system house these two forms of energy are perfectly compared in terms
of cost where in most cases study it is found that Dc is relatively cheaper as compared to AC.

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The case study of this will be done in depth in the research question part. And for the power
consumption in the hybrid solar system house the two forms are also compared in many
researches and study it has always been found that AC power consumption is relatively higher
than the DC for the same power rating of the devices used in the hybrid solar system house
(Newkirk, 2010). And again for the use of these two forms of electrical energy in hybrid solar
system house, it has always been found that AC is more dangerous to use in hybrid solar system
house. As compared to DC form of electrical energy, this will be explained why it is so in the
research question below.
Research questions
A comparative study based on the relevant criteria
Cost
To make a good comparison of these two forms of electricity in terms of cost in the
hybrid house, the cost of copper wire for transmission, cost of converters as well as the energy
required must be known. Economic inflation will be ignored. Under the following conditions,
converter losses we will give the power losses amount in the system (Keljik, 2018). And the
following equations can be written for the price power converters.
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The energy cost has been taken to be equal to 0.15 £/kWh, we consider the power converters
having a power rating of 100-150 W as the power supply dedicated.
Table 1: Showing Cost of electrical energy and electronic power converters
The electrical energy consumption in the hybrid can be projected to be as in table 2 below;
Table 2: Showing the consumption in a typical hybrid house in percentage