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How to Calculate Solar Energy System

Production

1. 1

Understanding Solar Radiation

You may wonder or may have never heard of this term. How does

solar radiation relate to residential solar energy systems, anyway?

These are questions and a topics to be discussed here as we dedicate

this article to explaining and highlighting the benefits of home solar

power.

This article also digs into the details and explains how kilowatts (kwh)are calculated when a solar panel converts sunlight into electricity.

Energy output from solar cells is based upon the total power generated

by your solar array. The content provided here will also walk through

the differences in the construction of solar panels tied together in

parallel versus solar panels connected in series.

2. 2

Figuring Out Average Energy Use

The average American home uses about 25 kWh of electricity per day.

The following example illustrates how to calculate the power

produced by a residential solar energy system. Looking over a solar

radiation grid, we can determine that a residence gets five daylight

hours of solar radiation in one day which is then averaged out over the

entire year.

Solar radiation maps are highlighted on may websites throughout theInternet. You can do a quick search for "solar radiation" to find one.

In any area across the entire United States, they detail out the amount

of sunshine hitting a given location based upon the time of year and

its address.

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3. 3

Calculating the Power from a Solar Energy System

Divide the average kWh per day by the average sun hours per day. For

this example, we take 25 kWh divided by 5 hours of sun per day = 5

kW system This 5 kW system will generate 25 kWhs under optimal

conditions in direct sunlight for 5 hours, or 25 kWh on an average day

with some at peak production and most of the sunlight at less than

optimal angles.

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Energy as it Pertains to Solar Modules

Individual solar modules that are measured in watts have a particular

voltage (around 40 volts) and a particular amperage (around 5 amps).

A solar module with 40 volts and 5 amps is called a 200-watt module,

which means that it has the potential to produce 200 watts of

electricity when in direct sunlight, away from trees or shading, and

clear of snow or debris. Since most electrical components around your

house are only rated for 600 volts DC, it is rare to see a solar array

with a string larger the 15 solar modules. On the other hand, since

inverters need a minimum voltage or pressure to turn them on, you

will seldom have a solar array with a string solar modules with a sizesmaller then 6.

Electrical components, like solar cells, panel modules or batteries, can

be connected in either series or parallel. This makes a big difference

in the total quantities of energy produced from the solar energy

system, as well as the stability of the technology over time. Each solar

module or component has a positive and a negative pole. This is the

same concept as the negative and positive poles you find on batteries

that run your electronic equipment. The way that these ends or polesare tied together makes a large difference.

5. 5

Connecting Solar (PV) Panels in Series

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When you connect residential solar energy systems in series, you

connect the positive (+) pole on one component to the negative (-)

pole on the next. When modules are connected in series, the voltages

are added. Adding voltage together in this fashion creates a long chain

of solar modules all working together, depending upon each other, and

creating a flow of current that increases along the length of the

system.

These modules in series are called Strings. The average string is 8-12

modules so the voltage would be 320 - 480. Unfortunately, we

encounter some negative aspects of of this type of construction.

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Connecting Solar (PV) Panels in Parallel

When you connect solar panels or components in parallel, you

connect the panels so current can travel to your inverter and to your

house via multiple paths. Unlike adding solar modules in series which

increases the volume of current as it goes, the solar panels connected

in parallel has the effective of leaving the current or volume of

electricity passing through the system the same.

Solar panels or strings of solar arrays tied together in parallel are

called parallel systems. Their amps are combined together but thetotal voltage remains the same. Adding amps is like increasing the

volume, the pressure stays the same but the volume goes up. Inverters

can only handle so much volume so you will seldom see more than 1

to 3 strings in parallel; positive ends to positive ends with negative

ends to negative ends.

One of the advantages of parallel connection is that electricity

continues to flow, even though one of the components (or strings) is

damaged. If a system is entirely in series, one damaged componentstops the entire system. You may remember the ever-frustrating

Christmas lights that were connected in series. Often difficult to

trouble shoot, strings of lights connected in series are hard to fix when

one bulb blew out. Now, the modern Christmas lights are connected in

parallel. You are able to determine this easily. There are usually two

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different wires coming in and out of each bulb. You can feel this via

their less frustrating maintenance and operation.

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Options for Residential Solar Energy Systems

In this article, we explained in some detail how solar modules

calculate the power they produce as well as how connecting solar

arrays in series or parallel can have an large impact on energy output

as well as complexity of design. Our next article will cover how sun

angle affects solar energy systems and how to quantify the solar

power produced from the sun.

New solar energy system rentals allow you to upgrade your home tosolar generated electricity with no large system to purchase. You can

rent the solar energy equipment needed to generate up to 100 percent

of your electricity needs. Exciting aspects related to clean, green solar

energy are emerging all around us.