Home Solar Energy Storage Systems

The standard solar power system used to provide electricity today consists chiefly of two components: PV (photovoltaic) panels and a storage system. The PV (photovoltaic) panels generate the electricity and the storage system stores any excess for later use when there isn’t enough sunlight to power all your needs.

Storage systems usually consist of a large number of batteries stored in a vented, safe location such as a basement or specially constructed room. Batteries are optional but in order to be completely ‘off grid’ some kind of storage system is needed and batteries are almost universally used to power these systems.

There are two basic kinds of batteries used in most systems: lead acid and nickel cadmium.

Lead acid batteries are by far the most common due to their lower cost. They are very similar to lead acid car batteries although there are some interesting differences which are discussed below. The batteries have positive and negative terminals (to which leads are attached) and contain metal plates that connect to the terminals. The plates sit in a chemical solution, typically sulfuric acid.

The chemical reaction between the lead plates inside the housing and the sulphuric acid mix produces electricity. When these substances chemically combine, they generate free electrons that flow through the terminals and down the attached leads to your home outlets. PV (photovoltaic) solar panel-generated electricity drives the chemical reaction backwards, (re)charging the batteries.

The same principles apply in the case of nickel cadmium batteries with some interesting practical differences. NiCad batteries are more expensive than lead acid but the price is justified by the fact that the latter delivers more value. They last much longer than other batteries and discharge more current before they need to be recharged.

Both types are known as deep-cycle batteries. Car batteries supply a lot of current for a short period of time – just long enough to start your car. Then the motor takes over to power the electrical devices – these are shallow cycle batteries. Solar power system batteries however are designed differently because they have to deliver a smaller current over a much longer period of time. These deep cycled devices work during the night when the PV (photovoltaic) panels are not delivering electricity to run the home or charge the batteries.

Charge Controllers

Draining a battery completely (or overcharging it repeatedly) would drastically shorten its lifetime; charge controllers are a device that is part of the system and stops this from happening.

When the battery reaches a certain level; the controller cuts of any drain to prevent the stored charge going below a designed-in level. It also cuts off once the battery reaches a pre-set stored charge level. Most are designed to allow lead acid batteries to discharge no more than 50% of capacity to ensure a long life.

PV (photovoltaic) panels will last for 20 years, but even good batteries may last no more than 10 years, often less. Extending their lifetime of the batteries is a key factor in keeping the overall investment in the system as low as possible.

Heating Your Home With The Sun

The idea of heating your home with the sun is hardly new; humankind has used the sun as a source of essential light and warmth since the dawn of time. However, the methods used even a few generations ago have been completely transformed with the use of modern technology.

Nowadays, modern methods of using solar energy to heat the home go well beyond simple windows.

In the 1920s some municipalities used large storage tanks that were heated by the sun to supply homes with hot water. However, the cost of these applications was too expensive to compete with the much lower unit cost of electricity and gas. Old ideas are often revived however with an added twist and the use of solar power to provide hot water has again been in use for the last thirty years or more.

Nowadays, modern methods of using solar energy to heat the home go well beyond simple windows. Simply allowing sunlight to stream into a window is insufficient as it often leads to areas of the home being too bright. Furthermore this method of using solar power results in hot spots in some areas while others receive too little heat.

Modern solar heating systems however, are designed to redirect solar energy to provide an even, comfortable temperature throughout the house. Some of these systems use water or a salt water mixture. The tubes and channels that contain the liquid sometimes lie in small parabolic mirror-type troughs that concentrate the sun’s rays to raise the water temperature. Many solar water heating systems work this way; the same technology can be adapted to supply heat to a home.

Most water systems are designed to prevent heat from escaping as this means that the water doesn’t have to be continually reheated – thus hot water is available on demand. In home heating systems this idea is reversed and some of the heat is allowed to escape.

In one application, a series of tubes runs under wooden, clay or other flooring materials. The system is designed in such a way as to allow the heat to gradually flow through the flooring and rise up into the air to provide a comfortable interior environment.

Clever designers have taken the idea one step further. They know that water is not the only common fluid in our environment – air is also a fluid (as distinct from a liquid) in scientific terms. What this means is that it has some of the properties of a liquid in that it flows easily. Filling these tubes with air or some other gas makes it possible to absorb and deposit heat where it is needed. More importantly if a leak occurs there is no major damage to the home as the gas is not a liquid.

These systems aren’t as dense as liquid systems which means they are less efficient when it comes to storing heat on the other hand you would not have to endure the cost of major repairs in case something goes wrong. If the system springs a leak, all that is needed is to patch it or replace a small section – a far less expensive operation than replacing flooring or walls after a water leak.

Such problems are not that rare; in climates where the weather becomes quite cold in the winter, the water inside pipes will sometimes freeze and the result is a broken pipe. At the same time there are many cold days where there is a good deal of sunshine that can be used in a solar heating system. These are just a few of the options available for use in the home.

Is Solar Power Worthwhile?

The cost of a solar system to power or heat your home can cost anywhere from a few thousand to $25,000 or more. The wide range of investment required is the result of many factors.

Whatever reasons..for deciding to opt for solar power, they share a common result: safe, clean, low-cost power. And that is something that everyone needs.

The amount of sunlight received in different areas varies considerably; some places like Santa Fe, New Mexico get an average 325 days sunshine a year. Seattle, on the other hand has only 58 clear days, 82 days that are partly cloudy and 226 days that are cloudy. In the first case, a solar system would provide ample electricity most of the year. In the case of somewhere like Seattle the efficiency would be much lower. People living in Seattle would require many more modules to get the needed amount of electricity and it is this that raises the cost.

Costs vary widely, too, irrespective of the area in which you may live. Some homes can be covered with panels for as little as $5,000, though the average cost is often closer to $16,000. Larger homes, obviously, require more panels and usage can also vary. If the home remains connected to the utility company grid the cost is lower since some power is still coming from the grid. In such a case having a battery storage system can easily double the cost.

Costs can be offset by certain factors. Federal programs, for example, provide tax rebates for those who choose to install a solar power system. The usual methods of reimbursement are either through direct payment or lower property taxes. Some states have similar programs of their own.

Different solar power system vendors provide their own discounts throughout the year, either through winter sales or an agreement to match or beat any price from another competitor. As with any product, it is possible to get a good deal, even on quality material. Improvements in manufacturing have lowered the cost of producing the equipment while at the same time increasing its efficiency. A wide variety of PV (photovoltaic) modules, batteries, charge controllers, inverters and other components are available today. Most work on the same principle as each other but like any product some businesses do a better job of manufacturing and marketing than others.

On the other side of the ledger, the cost of electricity from utility companies continues to rise in most areas and there appears to be no end in sight. Rising oil prices, continued heavy regulation of utility companies, the unnecessary death of the nuclear power industry and other factors all contribute to continually rising prices.

All things considered implementing a solar power system is still a worthwhile project. When the job is carried out properly, most people are glad they did. Solar power systems have a long life, are easy to maintain, cost-effective and produce or contribute to minimal pollution.

There is not a single answer to every circumstance, like most things, implementing a solar power system for your home involves trade offs. In the end, only you can decide whether it is worthwhile.

Whatever reasons people have for deciding to opt for solar power, they share a common result: safe, clean, low-cost power. And that is something that everyone needs.

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