Homemade Solar Cell

In most 3rd world places, where electricity and other fuel sources are hard to come by, solar oven designs have been used. Not only are they effective in cooking food, but also for water purification in sunny countries like Sudan.

And like other solar technologies, there’s no reason first world countries should not promote solar cooking at home to help save energy. Although cooking may take four times longer than conventional ovens, no electricity or fuel is used – just the power of the sun.

Over time many solar oven designs have been mastered, but they generally fall into three main categories: parabolic solar cookers, panel cookers, and box cookers.

Parabolic Shape:

As the name suggests, a parabolic cooker is made from reflective material that is molded into bowl. This helps it concentrate the sunlight in one area and effectively cook your food. However, this design typically costs more and it’s rigid structure makes it less practical for traveling.

Panel Cooker:

A panel cooker is any cooker made with a series of flat, reflective panels arranged to direct sunlight to a focal point.

The panel shape is not as efficient as the parabolic shape, but it has the advantage of being foldaway, portable, and rather simple to make. These cookers can be found in a number of interesting deigns, but the simplest is by far the one made by folding one of those reflective windscreen blinds.

Box Cooker:

The final shape is the box cooker. The concept behind this solar oven design is very different to the parabolic and panel cookers. Here, the cooker works by absorbing sunlight through perspex, trapping that sunlight and heat in the cooker, and creating more heat as more light streams in.

What makes the box cooker appealing is that is really easy to make – the simplest design requires a cardboard box, a piece of clear glass or plastic, and tin foil – and it can cook a large portion of food at a time.

What I like most about solar oven designs is that they can be put together with simple materials found at home in the course of an afternoon. It’s a fun project to do with your kids, and the shapes you come up with are really limited to your imagination. And do not just think your solar cooker is only good for boiling water or steaming vegetables. People have successfully roasted meat in them and even baked bread. Another pro is that your solar cooker will be outside when used, so it will not cause your whole kitchen to heat up and put strain on your indoor cooling system – another way it helps you to conserve energy.

And if you think that over 75% of American households use their oven or stove on a daily basis – a tremendous amount of energy could be conserved if more of us used solar oven designs during summer.

There really is no excuse for not looking more into solar cooking. With a number of affordable solar cookers and free instructions available on the internet, you owe it to yourself, your kids and the environment to try one out for yourself.

With our current economic melt down and energy prices fluctuating daily, many of us are thinking of installing solar panel power to contribute to our homes’ energy needs, and reduce our power bills.

But when you install solar power, how much do you actually have to generate to say cut your bills by 50%? And what kind of costs will you be looking at?

Here is a simple 4-step formula to help you calculate your home’s solar panel watt requirements and costs:

1 – How Much Power Do You Use Per Day?:

Your first step is to work out the average daily kilowatt hours (kWh) used. This can be done by looking back at your last twelve months power bills, and see how much power used per month, and get the monthly average. This will give you a better estimate of your average power needs by eliminating the effect of the seasons. It is calculated by adding up all 12 bills and dividing the total power used by 12. If you do not have the the past year’s bills, then look at your most recent one.

Then divide your monthly usage by 30 (the average number of days in a month, to get your daily power used.

- Here is an example: Lets say the power used last month was 800 kWh. Your average daily usage would be 800/30 = 26.7 kWh per day.

- Now if you want to only halve your power bill then you need to produce 26.7 / 2 = 13.4 kWh of solar panel watt power per day.

2 – Calculate Total Solar Panel Watt Needs:

Before you can work this out, you need to find out how many usable hours of sunlight your region gets per day. A simple way to find that out is to have a look at an insolation map – there is one available on our website, where the original article was posted.

Once you know your daily sunlight hours, go back to your daily kilowatt hours needed and divide it by the daily sunlight hours, then multiply it by a factor of 1.25 (takes into account energy losses from the solar panel watt wiring, battery , and inverter)

- From the previous example, if you live near California where the average daily usable hours of sunlight is 5.5 hrs, the solar wattage needed is:

13.4 kWh / 5.5hrs x 1.25 = 3.045 kW or 3045 Watts per day.

This means we need solar panels with the capacity to produce at least 3045 Watts of power.

3 – The Cost Of The Panels:

Next you need to work out how much it will cost to buy solar panels that produce at least 3045 Watts. Currently the highest average cost for solar panels in North America is $4.85 a Watt.

- In our example: It will cost us at the most 3045 x 4.85 = $14,768 to install solar panels to halve our power bill. And that’s before wiring, charge controllers, batteries, inverters, and electrician costs.

4 – Offset Tax Credits And Rebates:

Before you think you are going to have to fork out at least $14,768 for only 3045 Watt of solar panel power, you need to consider the effect of government subsidies and incentives.

With the new renewable energy tax credits going into effect from January 1, 2009, and state-side rebates from states such as New York, Connecticut, New Jersey or California, our solar installation costs will be much lower than expected.

- Continuing on from our example: If we lived in California, our state tax incentives would be about 20 % of the investment, and the federal rebates 40% of the remaining cost. So, our solar panels would only end up costing us:

$14,768 – $14,768 x (20%) – $14,768 x (1 – 20%) x 40% = $7,089.

Just remember that this formula is basic way for you to get an idea of what home solar power will cost you. Some things could not be factored in – such as the state or country you live in, the special offers of local solar companies and the cost of the other parts (inverters, charge controllers, batteries, installation fees).

However, from the example, you can see that for Californian to reduce their power bill by half, they would have to buy $14,768 worth of solar panels, costing them $7089 after rebates. A cheaper option would be to learn to source affordable and even free solar cells, and build your own solar panels. This can be done by following a relatively inexpensive step-by-step solar power manual, such as Earth4Energy.