DIY Solar Energy: Do-It-Yourself Projects for Around the Home

In the last few decades, solar energy has made giant technical and cost-reduction strides that have now put the technology within reach for the average homeowner. By taking advantage of DIY solar energy (DIY = Do-It-Yourself), you'll be able to help reduce your energy bills while contributing to a cleaner planet.

There are two ways to harness the sun's energy: by collecting solar heat for use in an indoor environment, and by generating electricity to help offset the more polluting forms of power from the utility companies.

DIY Solar Heat

We all know from experience that when sunlight floods into a room through an open window, the trapped air heats up. In tropical locations, solar heating is the only means for heating homes but in more northern climates, using the radiant energy of the sun can help reduce winter heating bills.

The easiest way to gather radiant heat in a home is to open the drapes on south facing windows. Assuming the windows are well insulated (i.e. not drafty), the winter sun will stream into the house and warm whatever objects it strikes. The added warmth will not heat the room entirely on its own but will help offset the primary heating source and reduce heating costs.

However, the ultraviolet light from the sun tends to fades colors, so these other simple do-it-yourself methods may come in handy:

  • Place a portable, dark-color placard (i.e. a spray-painted cardboard sheet) in the window to absorb the sunlight. This will prevent furniture & carpet from the fading but still captures solar heat. Only cover a portion of the window to allow for air-circulation and to let ambient light in the room. The obvious disadvantage of this method is that it's ugly.

  • In winter, change the blinds to a dark color that will absorb the solar radiation. Even inexpensive window shades will help. In the summer, replace them with light-colored blinds to reflect the excess heat outside.

More complicated solar heating strategies that you can do yourself include:

  • Solar Power Pool Heaters - these system require electricity to drive a circulation pump. The flowing water is forced through a large, flat metal surface that's exposed to the sun. The water absorbs the solar energy and is then re-circulated into the pool.

  • Active & Passive Solar Heat Collectors - these systems can be added to the south facing wall or roof of a home to collect heat from the winter sun. They're easier to add to a new home design rather than retrofitting into an existing building.

DIY Solar Energy

For the average homeowner, achieving total energy independence isn't financially feasible due to the initial cost outlay. Complete solar home heating and solar water heating systems cost tens of thousands of dollars and require trained and expensive installation people.

However, small systems can easily be put together to provide AC power for lights and small appliances. The assembly can be constructed out of the following parts which are readily available online or from local hardware stores:

  • Solar Panels - create DC electricity directly from sunlight. They have no moving parts and can last up to 30 years. The more efficient units are rigid, inflexible units that can be fixed mounted or attached to a tracking system. Peak performance is achieved when aligned at a 90 degree angle to the afternoon sun. Units can output up to 150 W for a 3x4 foot panel. There are even solar panel kits available so that you can build your own.

  • Power Inverters - Since most modern appliances run off of 120 V AC power, a power inverter is required to convert the DC electricity into AC current. Three are three types:

    • Square Wave Power Inverter - The voltage of typical AC power is smooth and repetitive like an ocean wave (called a sine wave). Square wave inverters produce a jagged-edge voltage wave that's inefficient and hard on electrical equipment. They may be inexpensive but they're only good for small system loads that are used infrequently.

    • Modified Sine Wave Power Inverter - These middle-of-the-road inverters produce an AC voltage waveform that's somewhat between a square wave and a true sine wave. These units are a little more expensive and are good for moderately-sized, stand-alone systems.

    • True Sine Wave Power Inverter - These inverters produce cleaner power than what is provided by utility companies. These units provide conditioned power that automatically adjusts the AC voltage waveform according to the power load. They are about twice the cost of a modified sine-wave power inverter but will help household appliances last a long time.

  • Charge Controllers (optional) - If reserve power is needed when the sun isn't shining, then batteries are required to store the charge. Charging is controlled by an inexpensive charge controller that prevents over-charging. Look for one that has a maximum power-point tracking (MPPT) circuit which produces the most efficient current-voltage ratio for optimal charging performance.

  • Batteries - These are not your typical car batteries but rather are more expensive, deep cycle units that can withstand the constant charge and discharge cycles of the daily solar charging cycle. Batteries come in 12 V units and can be ganged together to provide 24 V and 48 V strings. Higher voltage strings can be customized for your system to allow for lower electrical losses in the system.

 

 

The hardest part of a do-it-yourself solar energy project is determining the amount of power that is required for your application (See: Calculating Solar Power Needs). If you require power after sunset (or perhaps can't tolerate a 'black-out' when a cloud goes overhead), then consider adding a battery-pack to provide reserve power when the solar panels aren't generating enough electricity.

Precautions

  • Ensure the mounting of the solar panels is fixed and can withstand wind gusts and snow & ice buildup. Secure mounting will help to prevent any damage to the unit and to anything or anyone within its vicinity.

  • Use the appropriate size wire to handle the maximum amount of current. If the wire is too thin, it can become hot and cause a fire. Being too large will add unnecessary expense and electrical loss to the system.

  • Electricity and water don't mix. Ensure all electrical connections are weather proof. An electrician will be able to assist.

  • Batteries can be placed outdoors but should be protected from the elements. Cold batteries hold less charge and produce less current.

Solar energy is plentiful and free, and with a DIY solar energy project, you can customize a system that will tailor fit your exact requirements. Parts are readily available and, for the true handyman, it can be a fun project to design and assemble.

 

 

 


 

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