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home solar energy
from Daniel Stouffer


thing you might ask - what is solar radiation and how does it related to solar generated electricity? That is a good question and a topic discussed in our next article in our series dedicated to home solar power. This article, on the other hand, explains how kilowatts are calculated based upon the energy output of your solar array. We will also highlight the difference between solar cells connected in parallel versus in series.

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 the Internet. 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.

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.

Future articles related to solar energy will continue to explain the effects of sun angle, reflection, and refraction on the design, output, and installation of solar panels.

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 size smaller 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. In essence, this is the same way batteries have their negative and positive poles arranged. Take a look at how you but batteries in a flashlight. Same idea here. The manner in which these poles are connected makes a big difference. Connect Solar Panels in Series

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.

Connecting Solar 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 the total 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 component stops 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 different wires coming in and out of each bulb. You can feel this via their less frustrating maintenance and operation.

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 to solar 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.



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home solar energy
from Daniel Stouffer

You are contributing to a cleaner environment by upgrading to solar generated electricity. You are also taking a step toward energy independence when you begin using solar power in your home.

To better understand solar electric systems and how they work, you first need to understand the technical components making up a residential solar energy system.

New solar rental services are emerging that offer solar power in new and simple ways. There are a number of solar panel rental offers now on the market. They offer energy efficiency in your home, better control and tracking of home power, and make a home’s electricity services more reliable, and renewable.

This article explains, defined, and illustrates the parts and pieces going into a residential solar energy unit.

Solar Photovoltaic (PV) Panels

The primary components of a home solar system are the Solar (PV) panels. These panels utilize solar cells to convert sunlight directly into home electricity. A group of solar cells hooked together make a solar panel. A single solar panel can produce 250 watts (w) of electricity when the sun is shining at maximum capacity. The panels then route power through an inverter where a controller determines how to distribute the power throughout your home.

Solar Energy Controller and Inverter

The controller is the device that monitors and manages the distribution of electricity produced by a residential solar energy system. Its capability extends even further by monitoring and managing the flow of energy between the house, the solar (PV) panels & system, and the local utility company. Often these controllers also have the ability to manage secondary storage through the use of batteries for more flexibility and control.

Coupled with the controller is the brains of the operation; the inverter. An inverter is in essence an electronic circuit that converts direct current (DC) to alternating current (AC). An inverter allows the 12 or 24 volt DC power produced from solar panels to supply AC power to operate all of the electrical needs around your house.

Solar Array Mounting and Connection Components

Connection components are made up of electrical wiring and the rail mounting structure. Several solar panels are arranged into a grid, secured by a rail mounting device, and connected together to make a solar (PV) array. Electrical wiring is needed to connect the solar panels to the controller, then to your meter box, and then to your utility company via the existing electricity grid. Little additional solar energy equipment is needed, other than the panels, controller and inverters, wiring, and the roof mounting system.

The mounting rail is another simple structure that secures your solar (PV) array to your roof with the little need to drill holes through your singles. It is constructed with sturdy materials and engineering, allowing for quick assembly of the solar panels.

Rental Options for Residential Solar Energy Systems

Homeowners now have the ability to generate electricity right at home in safe, simple, and environmentally conscious way. Residential solar energy systems convert sunlight (i.e. photons) directly into usable home electricity. Residential solar energy systems, now offered to homeowners on a rental basis, provide a new source of reliable electricity and they enhance electric services without expensive investments in solar purchases.

In a future article, we will continue this series related to residential solar energy systems. We will explain in common terms how to measure the power of the sun. One objection often voiced by homeowners researching home solar power relates to the quality of the sunlight.

Is too cloudy? Is it too foggy? How does snow effect solar cell output? We will show how to calculate your sunlight hours and to determine if your part of the country gets adequate sunlight hours to have a solar system make sense.

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